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chromium / v8 / v8 / refs/heads/canary / . / src / interpreter / bytecode-generator.cc
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// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/interpreter/bytecode-generator.h"
#include <map>
#include <optional>
#include <unordered_map>
#include <unordered_set>
#include "include/v8-extension.h"
#include "src/api/api-inl.h"
#include "src/ast/ast-source-ranges.h"
#include "src/ast/ast.h"
#include "src/ast/scopes.h"
#include "src/builtins/builtins-constructor.h"
#include "src/codegen/compiler.h"
#include "src/codegen/unoptimized-compilation-info.h"
#include "src/common/globals.h"
#include "src/compiler-dispatcher/lazy-compile-dispatcher.h"
#include "src/heap/parked-scope.h"
#include "src/interpreter/bytecode-array-builder.h"
#include "src/interpreter/bytecode-flags-and-tokens.h"
#include "src/interpreter/bytecode-jump-table.h"
#include "src/interpreter/bytecode-label.h"
#include "src/interpreter/bytecode-register-allocator.h"
#include "src/interpreter/bytecode-register-optimizer.h"
#include "src/interpreter/bytecode-register.h"
#include "src/interpreter/control-flow-builders.h"
#include "src/logging/local-logger.h"
#include "src/logging/log.h"
#include "src/numbers/conversions.h"
#include "src/objects/debug-objects.h"
#include "src/objects/js-disposable-stack.h"
#include "src/objects/objects.h"
#include "src/objects/smi.h"
#include "src/objects/template-objects.h"
#include "src/parsing/parse-info.h"
#include "src/parsing/token.h"
#include "src/utils/ostreams.h"
namespace v8 {
namespace internal {
namespace interpreter {
// Scoped class tracking context objects created by the visitor. Represents
// mutations of the context chain within the function body, allowing pushing and
// popping of the current {context_register} during visitation.
class V8_NODISCARD BytecodeGenerator::ContextScope {
public:
ContextScope(BytecodeGenerator* generator, Scope* scope,
Register outer_context_reg = Register())
: generator_(generator),
scope_(scope),
outer_(generator_->execution_context()),
register_(Register::current_context()),
depth_(0) {
DCHECK(scope->NeedsContext() || outer_ == nullptr);
if (outer_) {
depth_ = outer_->depth_ + 1;
// Push the outer context into a new context register.
if (!outer_context_reg.is_valid()) {
outer_context_reg = generator_->register_allocator()->NewRegister();
}
outer_->set_register(outer_context_reg);
generator_->builder()->PushContext(outer_context_reg);
}
generator_->set_execution_context(this);
}
~ContextScope() {
if (outer_) {
DCHECK_EQ(register_.index(), Register::current_context().index());
generator_->builder()->PopContext(outer_->reg());
outer_->set_register(register_);
}
generator_->set_execution_context(outer_);
}
ContextScope(const ContextScope&) = delete;
ContextScope& operator=(const ContextScope&) = delete;
// Returns the depth of the given |scope| for the current execution context.
int ContextChainDepth(Scope* scope) {
return scope_->ContextChainLength(scope);
}
// Returns the execution context at |depth| in the current context chain if it
// is a function local execution context, otherwise returns nullptr.
ContextScope* Previous(int depth) {
if (depth > depth_) {
return nullptr;
}
ContextScope* previous = this;
for (int i = depth; i > 0; --i) {
previous = previous->outer_;
}
return previous;
}
Register reg() const { return register_; }
private:
const BytecodeArrayBuilder* builder() const { return generator_->builder(); }
void set_register(Register reg) { register_ = reg; }
BytecodeGenerator* generator_;
Scope* scope_;
ContextScope* outer_;
Register register_;
int depth_;
};
// Scoped class for tracking control statements entered by the
// visitor.
class V8_NODISCARD BytecodeGenerator::ControlScope {
public:
explicit ControlScope(BytecodeGenerator* generator)
: generator_(generator),
outer_(generator->execution_control()),
context_(generator->execution_context()) {
generator_->set_execution_control(this);
}
~ControlScope() { generator_->set_execution_control(outer()); }
ControlScope(const ControlScope&) = delete;
ControlScope& operator=(const ControlScope&) = delete;
void Break(Statement* stmt) {
PerformCommand(CMD_BREAK, stmt, kNoSourcePosition);
}
void Continue(Statement* stmt) {
PerformCommand(CMD_CONTINUE, stmt, kNoSourcePosition);
}
void ReturnAccumulator(int source_position) {
PerformCommand(CMD_RETURN, nullptr, source_position);
}
void AsyncReturnAccumulator(int source_position) {
PerformCommand(CMD_ASYNC_RETURN, nullptr, source_position);
}
class DeferredCommands;
protected:
enum Command {
CMD_BREAK,
CMD_CONTINUE,
CMD_RETURN,
CMD_ASYNC_RETURN,
CMD_RETHROW
};
static constexpr bool CommandUsesAccumulator(Command command) {
return command != CMD_BREAK && command != CMD_CONTINUE;
}
void PerformCommand(Command command, Statement* statement,
int source_position);
virtual bool Execute(Command command, Statement* statement,
int source_position) = 0;
// Helper to pop the context chain to a depth expected by this control scope.
// Note that it is the responsibility of each individual {Execute} method to
// trigger this when commands are handled and control-flow continues locally.
void PopContextToExpectedDepth();
BytecodeGenerator* generator() const { return generator_; }
ControlScope* outer() const { return outer_; }
ContextScope* context() const { return context_; }
private:
BytecodeGenerator* generator_;
ControlScope* outer_;
ContextScope* context_;
};
// Helper class for a try-finally control scope. It can record intercepted
// control-flow commands that cause entry into a finally-block, and re-apply
// them after again leaving that block. Special tokens are used to identify
// paths going through the finally-block to dispatch after leaving the block.
class V8_NODISCARD BytecodeGenerator::ControlScope::DeferredCommands final {
public:
DeferredCommands(BytecodeGenerator* generator, Register token_register,
Register result_register, Register message_register)
: generator_(generator),
deferred_(generator->zone()),
token_register_(token_register),
result_register_(result_register),
message_register_(message_register),
return_token_(-1),
async_return_token_(-1),
fallthrough_from_try_block_needed_(false) {
// There's always a rethrow path.
// TODO(leszeks): We could decouple deferred_ index and token to allow us
// to still push this lazily.
static_assert(
static_cast<int>(TryFinallyContinuationToken::kRethrowToken) == 0);
deferred_.push_back(
{CMD_RETHROW, nullptr,
static_cast<int>(TryFinallyContinuationToken::kRethrowToken)});
}
// One recorded control-flow command.
struct Entry {
Command command; // The command type being applied on this path.
Statement* statement; // The target statement for the command or {nullptr}.
int token; // A token identifying this particular path.
};
// Records a control-flow command while entering the finally-block. This also
// generates a new dispatch token that identifies one particular path. This
// expects the result to be in the accumulator.
void RecordCommand(Command command, Statement* statement) {
int token = GetTokenForCommand(command, statement);
DCHECK_LT(token, deferred_.size());
DCHECK_EQ(deferred_[token].command, command);
DCHECK_EQ(deferred_[token].statement, statement);
DCHECK_EQ(deferred_[token].token, token);
if (CommandUsesAccumulator(command)) {
builder()->StoreAccumulatorInRegister(result_register_);
}
builder()->LoadLiteral(Smi::FromInt(token));
builder()->StoreAccumulatorInRegister(token_register_);
if (!CommandUsesAccumulator(command)) {
// If we're not saving the accumulator in the result register, shove a
// harmless value there instead so that it is still considered "killed" in
// the liveness analysis. Normally we would LdaUndefined first, but the
// Smi token value is just as good, and by reusing it we save a bytecode.
builder()->StoreAccumulatorInRegister(result_register_);
}
if (command == CMD_RETHROW) {
// Clear message object as we enter the catch block. It will be restored
// if we rethrow.
builder()->LoadTheHole().SetPendingMessage().StoreAccumulatorInRegister(
message_register_);
}
}
// Records the dispatch token to be used to identify the re-throw path when
// the finally-block has been entered through the exception handler. This
// expects the exception to be in the accumulator.
void RecordHandlerReThrowPath() {
// The accumulator contains the exception object.
RecordCommand(CMD_RETHROW, nullptr);
}
// Records the dispatch token to be used to identify the implicit fall-through
// path at the end of a try-block into the corresponding finally-block.
void RecordFallThroughPath() {
fallthrough_from_try_block_needed_ = true;
builder()->LoadLiteral(Smi::FromInt(
static_cast<int>(TryFinallyContinuationToken::kFallthroughToken)));
builder()->StoreAccumulatorInRegister(token_register_);
// Since we're not saving the accumulator in the result register, shove a
// harmless value there instead so that it is still considered "killed" in
// the liveness analysis. Normally we would LdaUndefined first, but the Smi
// token value is just as good, and by reusing it we save a bytecode.
builder()->StoreAccumulatorInRegister(result_register_);
}
void ApplyDeferredCommand(const Entry& entry) {
if (entry.command == CMD_RETHROW) {
// Pending message object is restored on exit.
builder()
->LoadAccumulatorWithRegister(message_register_)
.SetPendingMessage();
}
if (CommandUsesAccumulator(entry.command)) {
builder()->LoadAccumulatorWithRegister(result_register_);
}
execution_control()->PerformCommand(entry.command, entry.statement,
kNoSourcePosition);
}
// Applies all recorded control-flow commands after the finally-block again.
// This generates a dynamic dispatch on the token from the entry point.
void ApplyDeferredCommands() {
if (deferred_.empty()) return;
BytecodeLabel fall_through_from_try_block;
if (deferred_.size() == 1) {
// For a single entry, just jump to the fallthrough if we don't match the
// entry token.
const Entry& entry = deferred_[0];
if (fallthrough_from_try_block_needed_) {
builder()
->LoadLiteral(Smi::FromInt(entry.token))
.CompareReference(token_register_)
.JumpIfFalse(ToBooleanMode::kAlreadyBoolean,
&fall_through_from_try_block);
}
ApplyDeferredCommand(entry);
} else {
// For multiple entries, build a jump table and switch on the token,
// jumping to the fallthrough if none of them match.
//
// If fallthrough from the try block is not needed, generate a jump table
// with one (1) fewer entries and reuse the fallthrough path for the final
// entry.
const int jump_table_base_value =
fallthrough_from_try_block_needed_ ? 0 : 1;
const int jump_table_size =
static_cast<int>(deferred_.size() - jump_table_base_value);
if (jump_table_size == 1) {
DCHECK_EQ(2, deferred_.size());
BytecodeLabel fall_through_to_final_entry;
const Entry& first_entry = deferred_[0];
const Entry& final_entry = deferred_[1];
builder()
->LoadLiteral(Smi::FromInt(first_entry.token))
.CompareReference(token_register_)
.JumpIfFalse(ToBooleanMode::kAlreadyBoolean,
&fall_through_to_final_entry);
ApplyDeferredCommand(first_entry);
builder()->Bind(&fall_through_to_final_entry);
ApplyDeferredCommand(final_entry);
} else {
BytecodeJumpTable* jump_table = builder()->AllocateJumpTable(
jump_table_size, jump_table_base_value);
builder()
->LoadAccumulatorWithRegister(token_register_)
.SwitchOnSmiNoFeedback(jump_table);
const Entry& first_entry = deferred_.front();
if (fallthrough_from_try_block_needed_) {
builder()->Jump(&fall_through_from_try_block);
builder()->Bind(jump_table, first_entry.token);
}
ApplyDeferredCommand(first_entry);
for (const Entry& entry : base::IterateWithoutFirst(deferred_)) {
builder()->Bind(jump_table, entry.token);
ApplyDeferredCommand(entry);
}
}
}
if (fallthrough_from_try_block_needed_) {
builder()->Bind(&fall_through_from_try_block);
}
}
BytecodeArrayBuilder* builder() { return generator_->builder(); }
ControlScope* execution_control() { return generator_->execution_control(); }
private:
int GetTokenForCommand(Command command, Statement* statement) {
switch (command) {
case CMD_RETURN:
return GetReturnToken();
case CMD_ASYNC_RETURN:
return GetAsyncReturnToken();
case CMD_RETHROW:
return static_cast<int>(TryFinallyContinuationToken::kRethrowToken);
default:
// TODO(leszeks): We could also search for entries with the same
// command and statement.
return GetNewTokenForCommand(command, statement);
}
}
int GetReturnToken() {
if (return_token_ == -1) {
return_token_ = GetNewTokenForCommand(CMD_RETURN, nullptr);
}
return return_token_;
}
int GetAsyncReturnToken() {
if (async_return_token_ == -1) {
async_return_token_ = GetNewTokenForCommand(CMD_ASYNC_RETURN, nullptr);
}
return async_return_token_;
}
int GetNewTokenForCommand(Command command, Statement* statement) {
int token = static_cast<int>(deferred_.size());
deferred_.push_back({command, statement, token});
return token;
}
BytecodeGenerator* generator_;
ZoneVector<Entry> deferred_;
Register token_register_;
Register result_register_;
Register message_register_;
// Tokens for commands that don't need a statement.
int return_token_;
int async_return_token_;
// Whether a fallthrough is possible.
bool fallthrough_from_try_block_needed_;
};
// Scoped class for dealing with control flow reaching the function level.
class BytecodeGenerator::ControlScopeForTopLevel final
: public BytecodeGenerator::ControlScope {
public:
explicit ControlScopeForTopLevel(BytecodeGenerator* generator)
: ControlScope(generator) {}
protected:
bool Execute(Command command, Statement* statement,
int source_position) override {
switch (command) {
case CMD_BREAK: // We should never see break/continue in top-level.
case CMD_CONTINUE:
UNREACHABLE();
case CMD_RETURN:
// No need to pop contexts, execution leaves the method body.
generator()->BuildReturn(source_position);
return true;
case CMD_ASYNC_RETURN:
// No need to pop contexts, execution leaves the method body.
generator()->BuildAsyncReturn(source_position);
return true;
case CMD_RETHROW:
// No need to pop contexts, execution leaves the method body.
generator()->BuildReThrow();
return true;
}
return false;
}
};
// Scoped class for enabling break inside blocks and switch blocks.
class BytecodeGenerator::ControlScopeForBreakable final
: public BytecodeGenerator::ControlScope {
public:
ControlScopeForBreakable(BytecodeGenerator* generator,
BreakableStatement* statement,
BreakableControlFlowBuilder* control_builder)
: ControlScope(generator),
statement_(statement),
control_builder_(control_builder) {}
protected:
bool Execute(Command command, Statement* statement,
int source_position) override {
if (statement != statement_) return false;
switch (command) {
case CMD_BREAK:
PopContextToExpectedDepth();
control_builder_->Break();
return true;
case CMD_CONTINUE:
case CMD_RETURN:
case CMD_ASYNC_RETURN:
case CMD_RETHROW:
break;
}
return false;
}
private:
Statement* statement_;
BreakableControlFlowBuilder* control_builder_;
};
// Scoped class for enabling 'break' and 'continue' in iteration
// constructs, e.g. do...while, while..., for...
class BytecodeGenerator::ControlScopeForIteration final
: public BytecodeGenerator::ControlScope {
public:
ControlScopeForIteration(BytecodeGenerator* generator,
IterationStatement* statement,
LoopBuilder* loop_builder)
: ControlScope(generator),
statement_(statement),
loop_builder_(loop_builder) {}
protected:
bool Execute(Command command, Statement* statement,
int source_position) override {
if (statement != statement_) return false;
switch (command) {
case CMD_BREAK:
PopContextToExpectedDepth();
loop_builder_->Break();
return true;
case CMD_CONTINUE:
PopContextToExpectedDepth();
loop_builder_->Continue();
return true;
case CMD_RETURN:
case CMD_ASYNC_RETURN:
case CMD_RETHROW:
break;
}
return false;
}
private:
Statement* statement_;
LoopBuilder* loop_builder_;
};
// Scoped class for enabling 'throw' in try-catch constructs.
class BytecodeGenerator::ControlScopeForTryCatch final
: public BytecodeGenerator::ControlScope {
public:
ControlScopeForTryCatch(BytecodeGenerator* generator,
TryCatchBuilder* try_catch_builder)
: ControlScope(generator) {}
protected:
bool Execute(Command command, Statement* statement,
int source_position) override {
switch (command) {
case CMD_BREAK:
case CMD_CONTINUE:
case CMD_RETURN:
case CMD_ASYNC_RETURN:
break;
case CMD_RETHROW:
// No need to pop contexts, execution re-enters the method body via the
// stack unwinding mechanism which itself restores contexts correctly.
generator()->BuildReThrow();
return true;
}
return false;
}
};
// Scoped class for enabling control flow through try-finally constructs.
class BytecodeGenerator::ControlScopeForTryFinally final
: public BytecodeGenerator::ControlScope {
public:
ControlScopeForTryFinally(BytecodeGenerator* generator,
TryFinallyBuilder* try_finally_builder,
DeferredCommands* commands)
: ControlScope(generator),
try_finally_builder_(try_finally_builder),
commands_(commands) {}
protected:
bool Execute(Command command, Statement* statement,
int source_position) override {
switch (command) {
case CMD_BREAK:
case CMD_CONTINUE:
case CMD_RETURN:
case CMD_ASYNC_RETURN:
case CMD_RETHROW:
PopContextToExpectedDepth();
// We don't record source_position here since we don't generate return
// bytecode right here and will generate it later as part of finally
// block. Each return bytecode generated in finally block will get own
// return source position from corresponded return statement or we'll
// use end of function if no return statement is presented.
commands_->RecordCommand(command, statement);
try_finally_builder_->LeaveTry();
return true;
}
return false;
}
private:
TryFinallyBuilder* try_finally_builder_;
DeferredCommands* commands_;
};
// Scoped class for collecting 'return' statements in a derived constructor.
// Derived constructors can only return undefined or objects, and this check
// must occur right before return (e.g., after `finally` blocks execute).
class BytecodeGenerator::ControlScopeForDerivedConstructor final
: public BytecodeGenerator::ControlScope {
public:
ControlScopeForDerivedConstructor(BytecodeGenerator* generator,
Register result_register,
BytecodeLabels* check_return_value_labels)
: ControlScope(generator),
result_register_(result_register),
check_return_value_labels_(check_return_value_labels) {}
protected:
bool Execute(Command command, Statement* statement,
int source_position) override {
// Constructors are never async.
DCHECK_NE(CMD_ASYNC_RETURN, command);
if (command == CMD_RETURN) {
PopContextToExpectedDepth();
generator()->builder()->SetStatementPosition(source_position);
generator()->builder()->StoreAccumulatorInRegister(result_register_);
generator()->builder()->Jump(check_return_value_labels_->New());
return true;
}
return false;
}
private:
Register result_register_;
BytecodeLabels* check_return_value_labels_;
};
// Allocate and fetch the coverage indices tracking NaryLogical Expressions.
class BytecodeGenerator::NaryCodeCoverageSlots {
public:
NaryCodeCoverageSlots(BytecodeGenerator* generator, NaryOperation* expr)
: generator_(generator) {
if (generator_->block_coverage_builder_ == nullptr) return;
for (size_t i = 0; i < expr->subsequent_length(); i++) {
coverage_slots_.push_back(
generator_->AllocateNaryBlockCoverageSlotIfEnabled(expr, i));
}
}
int GetSlotFor(size_t subsequent_expr_index) const {
if (generator_->block_coverage_builder_ == nullptr) {
return BlockCoverageBuilder::kNoCoverageArraySlot;
}
DCHECK(coverage_slots_.size() > subsequent_expr_index);
return coverage_slots_[subsequent_expr_index];
}
private:
BytecodeGenerator* generator_;
std::vector<int> coverage_slots_;
};
void BytecodeGenerator::ControlScope::PerformCommand(Command command,
Statement* statement,
int source_position) {
ControlScope* current = this;
do {
if (current->Execute(command, statement, source_position)) {
return;
}
current = current->outer();
} while (current != nullptr);
UNREACHABLE();
}
void BytecodeGenerator::ControlScope::PopContextToExpectedDepth() {
// Pop context to the expected depth. Note that this can in fact pop multiple
// contexts at once because the {PopContext} bytecode takes a saved register.
if (generator()->execution_context() != context()) {
generator()->builder()->PopContext(context()->reg());
}
}
class V8_NODISCARD BytecodeGenerator::RegisterAllocationScope final {
public:
explicit RegisterAllocationScope(BytecodeGenerator* generator)
: generator_(generator),
outer_next_register_index_(
generator->register_allocator()->next_register_index()) {}
~RegisterAllocationScope() {
generator_->register_allocator()->ReleaseRegisters(
outer_next_register_index_);
}
RegisterAllocationScope(const RegisterAllocationScope&) = delete;
RegisterAllocationScope& operator=(const RegisterAllocationScope&) = delete;
BytecodeGenerator* generator() const { return generator_; }
private:
BytecodeGenerator* generator_;
int outer_next_register_index_;
};
class V8_NODISCARD BytecodeGenerator::AccumulatorPreservingScope final {
public:
explicit AccumulatorPreservingScope(BytecodeGenerator* generator,
AccumulatorPreservingMode mode)
: generator_(generator) {
if (mode == AccumulatorPreservingMode::kPreserve) {
saved_accumulator_register_ =
generator_->register_allocator()->NewRegister();
generator_->builder()->StoreAccumulatorInRegister(
saved_accumulator_register_);
}
}
~AccumulatorPreservingScope() {
if (saved_accumulator_register_.is_valid()) {
generator_->builder()->LoadAccumulatorWithRegister(
saved_accumulator_register_);
}
}
AccumulatorPreservingScope(const AccumulatorPreservingScope&) = delete;
AccumulatorPreservingScope& operator=(const AccumulatorPreservingScope&) =
delete;
private:
BytecodeGenerator* generator_;
Register saved_accumulator_register_;
};
// Scoped base class for determining how the result of an expression will be
// used.
class V8_NODISCARD BytecodeGenerator::ExpressionResultScope {
public:
enum Kind : uint8_t {
// Evaluated for its side effects.
kEffect,
// Evaluated for its value (and side effects).
kValue,
kValueAsPropertyKey,
// Evaluated for control flow (and side effects).
kTest,
};
ExpressionResultScope(BytecodeGenerator* generator, Kind kind)
: outer_(generator->execution_result()),
allocator_(generator),
kind_(kind),
type_hint_(TypeHint::kUnknown) {
generator->set_execution_result(this);
}
~ExpressionResultScope() {
allocator_.generator()->set_execution_result(outer_);
}
ExpressionResultScope(const ExpressionResultScope&) = delete;
ExpressionResultScope& operator=(const ExpressionResultScope&) = delete;
bool IsEffect() const { return kind_ == kEffect; }
bool IsValue() const { return kind_ == kValue; }
bool IsValueAsPropertyKey() const { return kind_ == kValueAsPropertyKey; }
bool IsTest() const { return kind_ == kTest; }
TestResultScope* AsTest() {
DCHECK(IsTest());
return reinterpret_cast<TestResultScope*>(this);
}
// Specify expression always returns a Boolean result value.
void SetResultIsBoolean() {
DCHECK_EQ(type_hint_, TypeHint::kUnknown);
type_hint_ = TypeHint::kBoolean;
}
void SetResultIsString() {
DCHECK_EQ(type_hint_, TypeHint::kUnknown);
type_hint_ = TypeHint::kString;
}
void SetResultIsInternalizedString() {
DCHECK_EQ(type_hint_, TypeHint::kUnknown);
type_hint_ = TypeHint::kInternalizedString;
}
TypeHint type_hint() const { return type_hint_; }
private:
ExpressionResultScope* outer_;
RegisterAllocationScope allocator_;
Kind kind_;
TypeHint type_hint_;
};
// Scoped class used when the result of the current expression is not
// expected to produce a result.
class BytecodeGenerator::EffectResultScope final
: public ExpressionResultScope {
public:
explicit EffectResultScope(BytecodeGenerator* generator)
: ExpressionResultScope(generator, kEffect) {}
};
// Scoped class used when the result of the current expression to be
// evaluated should go into the interpreter's accumulator.
class V8_NODISCARD BytecodeGenerator::ValueResultScope final
: public ExpressionResultScope {
public:
explicit ValueResultScope(BytecodeGenerator* generator)
: ValueResultScope(generator, kValue) {}
ValueResultScope(BytecodeGenerator* generator, Kind kind)
: ExpressionResultScope(generator, kind) {
DCHECK(kind == kValue || kind == kValueAsPropertyKey);
}
};
// Scoped class used when the result of the current expression to be
// evaluated is only tested with jumps to two branches.
class V8_NODISCARD BytecodeGenerator::TestResultScope final
: public ExpressionResultScope {
public:
TestResultScope(BytecodeGenerator* generator, BytecodeLabels* then_labels,
BytecodeLabels* else_labels, TestFallthrough fallthrough)
: ExpressionResultScope(generator, kTest),
result_consumed_by_test_(false),
fallthrough_(fallthrough),
then_labels_(then_labels),
else_labels_(else_labels) {}
TestResultScope(const TestResultScope&) = delete;
TestResultScope& operator=(const TestResultScope&) = delete;
// Used when code special cases for TestResultScope and consumes any
// possible value by testing and jumping to a then/else label.
void SetResultConsumedByTest() { result_consumed_by_test_ = true; }
bool result_consumed_by_test() { return result_consumed_by_test_; }
// Inverts the control flow of the operation, swapping the then and else
// labels and the fallthrough.
void InvertControlFlow() {
std::swap(then_labels_, else_labels_);
fallthrough_ = inverted_fallthrough();
}
BytecodeLabel* NewThenLabel() { return then_labels_->New(); }
BytecodeLabel* NewElseLabel() { return else_labels_->New(); }
BytecodeLabels* then_labels() const { return then_labels_; }
BytecodeLabels* else_labels() const { return else_labels_; }
void set_then_labels(BytecodeLabels* then_labels) {
then_labels_ = then_labels;
}
void set_else_labels(BytecodeLabels* else_labels) {
else_labels_ = else_labels;
}
TestFallthrough fallthrough() const { return fallthrough_; }
TestFallthrough inverted_fallthrough() const {
switch (fallthrough_) {
case TestFallthrough::kThen:
return TestFallthrough::kElse;
case TestFallthrough::kElse:
return TestFallthrough::kThen;
default:
return TestFallthrough::kNone;
}
}
void set_fallthrough(TestFallthrough fallthrough) {
fallthrough_ = fallthrough;
}
private:
bool result_consumed_by_test_;
TestFallthrough fallthrough_;
BytecodeLabels* then_labels_;
BytecodeLabels* else_labels_;
};
// Used to build a list of toplevel declaration data.
class BytecodeGenerator::TopLevelDeclarationsBuilder final : public ZoneObject {
public:
template <typename IsolateT>
Handle<FixedArray> AllocateDeclarations(UnoptimizedCompilationInfo* info,
BytecodeGenerator* generator,
Handle<Script> script,
IsolateT* isolate) {
DCHECK(has_constant_pool_entry_);
Handle<FixedArray> data =
isolate->factory()->NewFixedArray(entry_slots_, AllocationType::kOld);
int array_index = 0;
if (info->scope()->is_module_scope()) {
for (Declaration* decl : *info->scope()->declarations()) {
Variable* var = decl->var();
if (!var->is_used()) continue;
if (var->location() != VariableLocation::MODULE) continue;
#ifdef DEBUG
int start = array_index;
#endif
if (decl->IsFunctionDeclaration()) {
FunctionLiteral* f = static_cast<FunctionDeclaration*>(decl)->fun();
DirectHandle<SharedFunctionInfo> sfi(
Compiler::GetSharedFunctionInfo(f, script, isolate));
// Return a null handle if any initial values can't be created. Caller
// will set stack overflow.
if (sfi.is_null()) return Handle<FixedArray>();
data->set(array_index++, *sfi);
int literal_index = generator->GetCachedCreateClosureSlot(f);
data->set(array_index++, Smi::FromInt(literal_index));
DCHECK(var->IsExport());
data->set(array_index++, Smi::FromInt(var->index()));
DCHECK_EQ(start + kModuleFunctionDeclarationSize, array_index);
} else if (var->IsExport() && var->binding_needs_init()) {
data->set(array_index++, Smi::FromInt(var->index()));
DCHECK_EQ(start + kModuleVariableDeclarationSize, array_index);
}
}
} else {
for (Declaration* decl : *info->scope()->declarations()) {
Variable* var = decl->var();
if (!var->is_used()) continue;
if (var->location() != VariableLocation::UNALLOCATED) continue;
#ifdef DEBUG
int start = array_index;
#endif
if (decl->IsVariableDeclaration()) {
data->set(array_index++, *var->raw_name()->string());
DCHECK_EQ(start + kGlobalVariableDeclarationSize, array_index);
} else {
FunctionLiteral* f = static_cast<FunctionDeclaration*>(decl)->fun();
DirectHandle<SharedFunctionInfo> sfi(
Compiler::GetSharedFunctionInfo(f, script, isolate));
// Return a null handle if any initial values can't be created. Caller
// will set stack overflow.
if (sfi.is_null()) return Handle<FixedArray>();
data->set(array_index++, *sfi);
int literal_index = generator->GetCachedCreateClosureSlot(f);
data->set(array_index++, Smi::FromInt(literal_index));
DCHECK_EQ(start + kGlobalFunctionDeclarationSize, array_index);
}
}
}
DCHECK_EQ(array_index, data->length());
return data;
}
size_t constant_pool_entry() {
DCHECK(has_constant_pool_entry_);
return constant_pool_entry_;
}
void set_constant_pool_entry(size_t constant_pool_entry) {
DCHECK(has_top_level_declaration());
DCHECK(!has_constant_pool_entry_);
constant_pool_entry_ = constant_pool_entry;
has_constant_pool_entry_ = true;
}
void record_global_variable_declaration() {
entry_slots_ += kGlobalVariableDeclarationSize;
}
void record_global_function_declaration() {
entry_slots_ += kGlobalFunctionDeclarationSize;
}
void record_module_variable_declaration() {
entry_slots_ += kModuleVariableDeclarationSize;
}
void record_module_function_declaration() {
entry_slots_ += kModuleFunctionDeclarationSize;
}
bool has_top_level_declaration() { return entry_slots_ > 0; }
bool processed() { return processed_; }
void mark_processed() { processed_ = true; }
private:
const int kGlobalVariableDeclarationSize = 1;
const int kGlobalFunctionDeclarationSize = 2;
const int kModuleVariableDeclarationSize = 1;
const int kModuleFunctionDeclarationSize = 3;
size_t constant_pool_entry_ = 0;
int entry_slots_ = 0;
bool has_constant_pool_entry_ = false;
bool processed_ = false;
};
class V8_NODISCARD BytecodeGenerator::CurrentScope final {
public:
CurrentScope(BytecodeGenerator* generator, Scope* scope)
: generator_(generator), outer_scope_(generator->current_scope()) {
if (scope != nullptr) {
DCHECK_EQ(outer_scope_, scope->outer_scope());
generator_->set_current_scope(scope);
}
}
~CurrentScope() {
if (outer_scope_ != generator_->current_scope()) {
generator_->set_current_scope(outer_scope_);
}
}
CurrentScope(const CurrentScope&) = delete;
CurrentScope& operator=(const CurrentScope&) = delete;
private:
BytecodeGenerator* generator_;
Scope* outer_scope_;
};
class V8_NODISCARD BytecodeGenerator::MultipleEntryBlockContextScope {
public:
MultipleEntryBlockContextScope(BytecodeGenerator* generator, Scope* scope)
: generator_(generator), scope_(scope), is_in_scope_(false) {
if (scope) {
inner_context_ = generator->register_allocator()->NewRegister();
outer_context_ = generator->register_allocator()->NewRegister();
generator->BuildNewLocalBlockContext(scope_);
generator->builder()->StoreAccumulatorInRegister(inner_context_);
}
}
void SetEnteredIf(bool condition) {
RegisterAllocationScope register_scope(generator_);
if (condition && scope_ != nullptr && !is_in_scope_) {
EnterScope();
} else if (!condition && is_in_scope_) {
ExitScope();
}
}
~MultipleEntryBlockContextScope() { DCHECK(!is_in_scope_); }
MultipleEntryBlockContextScope(const MultipleEntryBlockContextScope&) =
delete;
MultipleEntryBlockContextScope& operator=(
const MultipleEntryBlockContextScope&) = delete;
private:
void EnterScope() {
DCHECK(inner_context_.is_valid());
DCHECK(outer_context_.is_valid());
DCHECK(!is_in_scope_);
generator_->builder()->LoadAccumulatorWithRegister(inner_context_);
current_scope_.emplace(generator_, scope_);
context_scope_.emplace(generator_, scope_, outer_context_);
is_in_scope_ = true;
}
void ExitScope() {
DCHECK(inner_context_.is_valid());
DCHECK(outer_context_.is_valid());
DCHECK(is_in_scope_);
context_scope_ = std::nullopt;
current_scope_ = std::nullopt;
is_in_scope_ = false;
}
BytecodeGenerator* generator_;
Scope* scope_;
Register inner_context_;
Register outer_context_;
bool is_in_scope_;
std::optional<CurrentScope> current_scope_;
std::optional<ContextScope> context_scope_;
};
class BytecodeGenerator::FeedbackSlotCache : public ZoneObject {
public:
enum class SlotKind {
kStoreGlobalSloppy,
kStoreGlobalStrict,
kSetNamedStrict,
kSetNamedSloppy,
kLoadProperty,
kLoadSuperProperty,
kLoadGlobalNotInsideTypeof,
kLoadGlobalInsideTypeof,
kClosureFeedbackCell
};
explicit FeedbackSlotCache(Zone* zone) : map_(zone) {}
void Put(SlotKind slot_kind, Variable* variable, int slot_index) {
PutImpl(slot_kind, 0, variable, slot_index);
}
void Put(SlotKind slot_kind, AstNode* node, int slot_index) {
PutImpl(slot_kind, 0, node, slot_index);
}
void Put(SlotKind slot_kind, int variable_index, const AstRawString* name,
int slot_index) {
PutImpl(slot_kind, variable_index, name, slot_index);
}
void Put(SlotKind slot_kind, const AstRawString* name, int slot_index) {
PutImpl(slot_kind, 0, name, slot_index);
}
int Get(SlotKind slot_kind, Variable* variable) const {
return GetImpl(slot_kind, 0, variable);
}
int Get(SlotKind slot_kind, AstNode* node) const {
return GetImpl(slot_kind, 0, node);
}
int Get(SlotKind slot_kind, int variable_index,
const AstRawString* name) const {
return GetImpl(slot_kind, variable_index, name);
}
int Get(SlotKind slot_kind, const AstRawString* name) const {
return GetImpl(slot_kind, 0, name);
}
private:
using Key = std::tuple<SlotKind, int, const void*>;
void PutImpl(SlotKind slot_kind, int index, const void* node,
int slot_index) {
Key key = std::make_tuple(slot_kind, index, node);
auto entry = std::make_pair(key, slot_index);
map_.insert(entry);
}
int GetImpl(SlotKind slot_kind, int index, const void* node) const {
Key key = std::make_tuple(slot_kind, index, node);
auto iter = map_.find(key);
if (iter != map_.end()) {
return iter->second;
}
return -1;
}
ZoneMap<Key, int> map_;
};
// Scoped class to help elide hole checks within a conditionally executed basic
// block. Each conditionally executed basic block must have a scope to emit
// hole checks correctly.
//
// The duration of the scope must correspond to a basic block. Numbered
// Variables (see Variable::HoleCheckBitmap) are remembered in the bitmap when
// the first hole check is emitted. Subsequent hole checks are elided.
//
// On scope exit, the hole check state at construction time is restored.
class V8_NODISCARD BytecodeGenerator::HoleCheckElisionScope {
public:
explicit HoleCheckElisionScope(BytecodeGenerator* bytecode_generator)
: HoleCheckElisionScope(&bytecode_generator->hole_check_bitmap_) {}
~HoleCheckElisionScope() { *bitmap_ = prev_bitmap_value_; }
protected:
explicit HoleCheckElisionScope(Variable::HoleCheckBitmap* bitmap)
: bitmap_(bitmap), prev_bitmap_value_(*bitmap) {}
Variable::HoleCheckBitmap* bitmap_;
Variable::HoleCheckBitmap prev_bitmap_value_;
};
// Scoped class to help elide hole checks within control flow that branch and
// merge.
//
// Each such control flow construct (e.g., if-else, ternary expressions) must
// have a scope to emit hole checks correctly. Additionally, each branch must
// have a Branch.
//
// The Merge or MergeIf method must be called to merge variables that have been
// hole-checked along every branch are marked as no longer needing a hole check.
//
// Example:
//
// HoleCheckElisionMergeScope merge_elider(this);
// {
// HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
// Visit(then_branch);
// }
// {
// HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
// Visit(else_branch);
// }
// merge_elider.Merge();
//
// Conversely, it is incorrect to use this class for control flow constructs
// that do not merge (e.g., if without else). HoleCheckElisionScope should be
// used for those cases.
class V8_NODISCARD BytecodeGenerator::HoleCheckElisionMergeScope final {
public:
explicit HoleCheckElisionMergeScope(BytecodeGenerator* bytecode_generator)
: bitmap_(&bytecode_generator->hole_check_bitmap_) {}
~HoleCheckElisionMergeScope() {
// Did you forget to call Merge or MergeIf?
DCHECK(merge_called_);
}
void Merge() {
DCHECK_NE(UINT64_MAX, merge_value_);
*bitmap_ = merge_value_;
#ifdef DEBUG
merge_called_ = true;
#endif
}
void MergeIf(bool cond) {
if (cond) Merge();
#ifdef DEBUG
merge_called_ = true;
#endif
}
class V8_NODISCARD Branch final : public HoleCheckElisionScope {
public:
explicit Branch(HoleCheckElisionMergeScope& merge_into)
: HoleCheckElisionScope(merge_into.bitmap_),
merge_into_bitmap_(&merge_into.merge_value_) {}
~Branch() { *merge_into_bitmap_ &= *bitmap_; }
private:
Variable::HoleCheckBitmap* merge_into_bitmap_;
};
private:
Variable::HoleCheckBitmap* bitmap_;
Variable::HoleCheckBitmap merge_value_ = UINT64_MAX;
#ifdef DEBUG
bool merge_called_ = false;
#endif
};
class BytecodeGenerator::IteratorRecord final {
public:
IteratorRecord(Register object_register, Register next_register,
IteratorType type = IteratorType::kNormal)
: type_(type), object_(object_register), next_(next_register) {
DCHECK(object_.is_valid() && next_.is_valid());
}
inline IteratorType type() const { return type_; }
inline Register object() const { return object_; }
inline Register next() const { return next_; }
private:
IteratorType type_;
Register object_;
Register next_;
};
class V8_NODISCARD BytecodeGenerator::OptionalChainNullLabelScope final {
public:
explicit OptionalChainNullLabelScope(BytecodeGenerator* bytecode_generator)
: bytecode_generator_(bytecode_generator),
labels_(bytecode_generator->zone()) {
prev_ = bytecode_generator_->optional_chaining_null_labels_;
bytecode_generator_->optional_chaining_null_labels_ = &labels_;
}
~OptionalChainNullLabelScope() {
bytecode_generator_->optional_chaining_null_labels_ = prev_;
}
BytecodeLabels* labels() { return &labels_; }
private:
BytecodeGenerator* bytecode_generator_;
BytecodeLabels labels_;
BytecodeLabels* prev_;
};
// LoopScope delimits the scope of {loop}, from its header to its final jump.
// It should be constructed iff a (conceptual) back edge should be produced. In
// the case of creating a LoopBuilder but never emitting the loop, it is valid
// to skip the creation of LoopScope.
class V8_NODISCARD BytecodeGenerator::LoopScope final {
public:
explicit LoopScope(BytecodeGenerator* bytecode_generator, LoopBuilder* loop)
: bytecode_generator_(bytecode_generator),
parent_loop_scope_(bytecode_generator_->current_loop_scope()),
loop_builder_(loop) {
loop_builder_->LoopHeader();
bytecode_generator_->set_current_loop_scope(this);
bytecode_generator_->loop_depth_++;
}
~LoopScope() {
bytecode_generator_->loop_depth_--;
bytecode_generator_->set_current_loop_scope(parent_loop_scope_);
DCHECK_GE(bytecode_generator_->loop_depth_, 0);
loop_builder_->JumpToHeader(
bytecode_generator_->loop_depth_,
parent_loop_scope_ ? parent_loop_scope_->loop_builder_ : nullptr);
}
private:
BytecodeGenerator* const bytecode_generator_;
LoopScope* const parent_loop_scope_;
LoopBuilder* const loop_builder_;
};
class V8_NODISCARD BytecodeGenerator::ForInScope final {
public:
explicit ForInScope(BytecodeGenerator* bytecode_generator,
ForInStatement* stmt, Register enum_index,
Register cache_type)
: bytecode_generator_(bytecode_generator),
parent_for_in_scope_(bytecode_generator_->current_for_in_scope()),
each_var_(nullptr),
enum_index_(enum_index),
cache_type_(cache_type) {
if (v8_flags.enable_enumerated_keyed_access_bytecode) {
Expression* each = stmt->each();
if (each->IsVariableProxy()) {
Variable* each_var = each->AsVariableProxy()->var();
if (each_var->IsStackLocal()) {
each_var_ = each_var;
bytecode_generator_->SetVariableInRegister(
each_var_,
bytecode_generator_->builder()->Local(each_var_->index()));
}
}
bytecode_generator_->set_current_for_in_scope(this);
}
}
~ForInScope() {
if (v8_flags.enable_enumerated_keyed_access_bytecode) {
bytecode_generator_->set_current_for_in_scope(parent_for_in_scope_);
}
}
// Get corresponding {ForInScope} for a given {each} variable.
ForInScope* GetForInScope(Variable* each) {
DCHECK(v8_flags.enable_enumerated_keyed_access_bytecode);
ForInScope* scope = this;
do {
if (each == scope->each_var_) break;
scope = scope->parent_for_in_scope_;
} while (scope != nullptr);
return scope;
}
Register enum_index() { return enum_index_; }
Register cache_type() { return cache_type_; }
private:
BytecodeGenerator* const bytecode_generator_;
ForInScope* const parent_for_in_scope_;
Variable* each_var_;
Register enum_index_;
Register cache_type_;
};
class V8_NODISCARD BytecodeGenerator::DisposablesStackScope final {
public:
explicit DisposablesStackScope(BytecodeGenerator* bytecode_generator)
: bytecode_generator_(bytecode_generator),
prev_disposables_stack_(
bytecode_generator_->current_disposables_stack_) {
bytecode_generator_->set_current_disposables_stack(
bytecode_generator->register_allocator()->NewRegister());
bytecode_generator->builder()->CallRuntime(
Runtime::kInitializeDisposableStack);
bytecode_generator->builder()->StoreAccumulatorInRegister(
bytecode_generator_->current_disposables_stack());
}
~DisposablesStackScope() {
bytecode_generator_->set_current_disposables_stack(prev_disposables_stack_);
}
private:
BytecodeGenerator* const bytecode_generator_;
Register prev_disposables_stack_;
};
namespace {
template <typename PropertyT>
struct Accessors : public ZoneObject {
Accessors() : getter(nullptr), setter(nullptr) {}
PropertyT* getter;
PropertyT* setter;
};
// A map from property names to getter/setter pairs allocated in the zone that
// also provides a way of accessing the pairs in the order they were first
// added so that the generated bytecode is always the same.
template <typename PropertyT>
class AccessorTable
: public base::TemplateHashMap<Literal, Accessors<PropertyT>,
bool (*)(void*, void*),
ZoneAllocationPolicy> {
public:
explicit AccessorTable(Zone* zone)
: base::TemplateHashMap<Literal, Accessors<PropertyT>,
bool (*)(void*, void*), ZoneAllocationPolicy>(
Literal::Match, ZoneAllocationPolicy(zone)),
zone_(zone) {}
Accessors<PropertyT>* LookupOrInsert(Literal* key) {
auto it = this->find(key, true);
if (it->second == nullptr) {
it->second = zone_->New<Accessors<PropertyT>>();
ordered_accessors_.push_back({key, it->second});
}
return it->second;
}
const std::vector<std::pair<Literal*, Accessors<PropertyT>*>>&
ordered_accessors() {
return ordered_accessors_;
}
private:
std::vector<std::pair<Literal*, Accessors<PropertyT>*>> ordered_accessors_;
Zone* zone_;
};
} // namespace
#ifdef DEBUG
static bool IsInEagerLiterals(
FunctionLiteral* literal,
const std::vector<FunctionLiteral*>& eager_literals) {
for (FunctionLiteral* eager_literal : eager_literals) {
if (literal == eager_literal) return true;
}
return false;
}
#endif // DEBUG
BytecodeGenerator::BytecodeGenerator(
LocalIsolate* local_isolate, Zone* compile_zone,
UnoptimizedCompilationInfo* info,
const AstStringConstants* ast_string_constants,
std::vector<FunctionLiteral*>* eager_inner_literals, Handle<Script> script)
: local_isolate_(local_isolate),
zone_(compile_zone),
builder_(zone(), info->num_parameters_including_this(),
info->scope()->num_stack_slots(), info->feedback_vector_spec(),
info->SourcePositionRecordingMode()),
info_(info),
ast_string_constants_(ast_string_constants),
closure_scope_(info->scope()),
current_scope_(info->scope()),
eager_inner_literals_(eager_inner_literals),
script_(script),
feedback_slot_cache_(zone()->New<FeedbackSlotCache>(zone())),
top_level_builder_(zone()->New<TopLevelDeclarationsBuilder>()),
block_coverage_builder_(nullptr),
function_literals_(0, zone()),
native_function_literals_(0, zone()),
object_literals_(0, zone()),
array_literals_(0, zone()),
class_literals_(0, zone()),
template_objects_(0, zone()),
vars_in_hole_check_bitmap_(0, zone()),
eval_calls_(0, zone()),
execution_control_(nullptr),
execution_context_(nullptr),
execution_result_(nullptr),
incoming_new_target_or_generator_(),
current_disposables_stack_(),
optional_chaining_null_labels_(nullptr),
dummy_feedback_slot_(feedback_spec(), FeedbackSlotKind::kCompareOp),
generator_jump_table_(nullptr),
suspend_count_(0),
loop_depth_(0),
hole_check_bitmap_(0),
current_loop_scope_(nullptr),
current_for_in_scope_(nullptr),
catch_prediction_(HandlerTable::UNCAUGHT) {
DCHECK_EQ(closure_scope(), closure_scope()->GetClosureScope());
if (info->has_source_range_map()) {
block_coverage_builder_ = zone()->New<BlockCoverageBuilder>(
zone(), builder(), info->source_range_map());
}
}
namespace {
template <typename Isolate>
struct NullContextScopeHelper;
template <>
struct NullContextScopeHelper<Isolate> {
using Type = NullContextScope;
};
template <>
struct NullContextScopeHelper<LocalIsolate> {
class V8_NODISCARD DummyNullContextScope {
public:
explicit DummyNullContextScope(LocalIsolate*) {}
};
using Type = DummyNullContextScope;
};
template <typename Isolate>
using NullContextScopeFor = typename NullContextScopeHelper<Isolate>::Type;
} // namespace
template <typename IsolateT>
Handle<BytecodeArray> BytecodeGenerator::FinalizeBytecode(
IsolateT* isolate, Handle<Script> script) {
DCHECK_EQ(ThreadId::Current(), isolate->thread_id());
#ifdef DEBUG
// Unoptimized compilation should be context-independent. Verify that we don't
// access the native context by nulling it out during finalization.
NullContextScopeFor<IsolateT> null_context_scope(isolate);
#endif
AllocateDeferredConstants(isolate, script);
if (block_coverage_builder_) {
Handle<CoverageInfo> coverage_info =
isolate->factory()->NewCoverageInfo(block_coverage_builder_->slots());
info()->set_coverage_info(coverage_info);
if (v8_flags.trace_block_coverage) {
StdoutStream os;
coverage_info->CoverageInfoPrint(os, info()->literal()->GetDebugName());
}
}
if (HasStackOverflow()) return Handle<BytecodeArray>();
Handle<BytecodeArray> bytecode_array = builder()->ToBytecodeArray(isolate);
if (incoming_new_target_or_generator_.is_valid()) {
bytecode_array->set_incoming_new_target_or_generator_register(
incoming_new_target_or_generator_);
}
return bytecode_array;
}
template Handle<BytecodeArray> BytecodeGenerator::FinalizeBytecode(
Isolate* isolate, Handle<Script> script);
template Handle<BytecodeArray> BytecodeGenerator::FinalizeBytecode(
LocalIsolate* isolate, Handle<Script> script);
template <typename IsolateT>
DirectHandle<TrustedByteArray> BytecodeGenerator::FinalizeSourcePositionTable(
IsolateT* isolate) {
DCHECK_EQ(ThreadId::Current(), isolate->thread_id());
#ifdef DEBUG
// Unoptimized compilation should be context-independent. Verify that we don't
// access the native context by nulling it out during finalization.
NullContextScopeFor<IsolateT> null_context_scope(isolate);
#endif
DirectHandle<TrustedByteArray> source_position_table =
builder()->ToSourcePositionTable(isolate);
LOG_CODE_EVENT(isolate,
CodeLinePosInfoRecordEvent(
info_->bytecode_array()->GetFirstBytecodeAddress(),
*source_position_table, JitCodeEvent::BYTE_CODE));
return source_position_table;
}
template DirectHandle<TrustedByteArray>
BytecodeGenerator::FinalizeSourcePositionTable(Isolate* isolate);
template DirectHandle<TrustedByteArray>
BytecodeGenerator::FinalizeSourcePositionTable(LocalIsolate* isolate);
#ifdef DEBUG
int BytecodeGenerator::CheckBytecodeMatches(Tagged<BytecodeArray> bytecode) {
return builder()->CheckBytecodeMatches(bytecode);
}
#endif
template <typename IsolateT>
void BytecodeGenerator::AllocateDeferredConstants(IsolateT* isolate,
Handle<Script> script) {
if (top_level_builder()->has_top_level_declaration()) {
// Build global declaration pair array.
Handle<FixedArray> declarations = top_level_builder()->AllocateDeclarations(
info(), this, script, isolate);
if (declarations.is_null()) return SetStackOverflow();
builder()->SetDeferredConstantPoolEntry(
top_level_builder()->constant_pool_entry(), declarations);
}
// Find or build shared function infos.
for (std::pair<FunctionLiteral*, size_t> literal : function_literals_) {
FunctionLiteral* expr = literal.first;
DirectHandle<SharedFunctionInfo> shared_info =
Compiler::GetSharedFunctionInfo(expr, script, isolate);
if (shared_info.is_null()) return SetStackOverflow();
builder()->SetDeferredConstantPoolEntry(
literal.second, indirect_handle(shared_info, isolate));
}
// Find or build shared function infos for the native function templates.
for (std::pair<NativeFunctionLiteral*, size_t> literal :
native_function_literals_) {
// This should only happen for main-thread compilations.
DCHECK((std::is_same_v<Isolate, v8::internal::Isolate>));
NativeFunctionLiteral* expr = literal.first;
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
// Compute the function template for the native function.
v8::Local<v8::FunctionTemplate> info =
expr->extension()->GetNativeFunctionTemplate(
v8_isolate, Utils::ToLocal(expr->name()));
DCHECK(!info.IsEmpty());
Handle<SharedFunctionInfo> shared_info =
FunctionTemplateInfo::GetOrCreateSharedFunctionInfo(
isolate, Utils::OpenDirectHandle(*info), expr->name());
DCHECK(!shared_info.is_null());
builder()->SetDeferredConstantPoolEntry(literal.second, shared_info);
}
for (std::pair<Call*, Scope*> call : eval_calls_) {
script->infos()->set(call.first->eval_scope_info_index(),
MakeWeak(*call.second->scope_info()));
}
// Build object literal constant properties
for (std::pair<ObjectLiteralBoilerplateBuilder*, size_t> literal :
object_literals_) {
ObjectLiteralBoilerplateBuilder* object_literal_builder = literal.first;
if (object_literal_builder->properties_count() > 0) {
// If constant properties is an empty fixed array, we've already added it
// to the constant pool when visiting the object literal.
Handle<ObjectBoilerplateDescription> constant_properties =
object_literal_builder->GetOrBuildBoilerplateDescription(isolate);
builder()->SetDeferredConstantPoolEntry(literal.second,
constant_properties);
}
}
// Build array literal constant elements
for (std::pair<ArrayLiteralBoilerplateBuilder*, size_t> literal :
array_literals_) {
ArrayLiteralBoilerplateBuilder* array_literal_builder = literal.first;
Handle<ArrayBoilerplateDescription> constant_elements =
array_literal_builder->GetOrBuildBoilerplateDescription(isolate);
builder()->SetDeferredConstantPoolEntry(literal.second, constant_elements);
}
// Build class literal boilerplates.
for (std::pair<ClassLiteral*, size_t> literal : class_literals_) {
ClassLiteral* class_literal = literal.first;
Handle<ClassBoilerplate> class_boilerplate =
ClassBoilerplate::New(isolate, class_literal, AllocationType::kOld);
builder()->SetDeferredConstantPoolEntry(literal.second, class_boilerplate);
}
// Build template literals.
for (std::pair<GetTemplateObject*, size_t> literal : template_objects_) {
GetTemplateObject* get_template_object = literal.first;
Handle<TemplateObjectDescription> description =
get_template_object->GetOrBuildDescription(isolate);
builder()->SetDeferredConstantPoolEntry(literal.second, description);
}
}
template void BytecodeGenerator::AllocateDeferredConstants(
Isolate* isolate, Handle<Script> script);
template void BytecodeGenerator::AllocateDeferredConstants(
LocalIsolate* isolate, Handle<Script> script);
namespace {
bool NeedsContextInitialization(DeclarationScope* scope) {
return scope->NeedsContext() && !scope->is_script_scope() &&
!scope->is_module_scope();
}
} // namespace
void BytecodeGenerator::GenerateBytecode(uintptr_t stack_limit) {
InitializeAstVisitor(stack_limit);
if (v8_flags.stress_lazy_compilation && local_isolate_->is_main_thread() &&
!local_isolate_->AsIsolate()->bootstrapper()->IsActive()) {
// Trigger stack overflow with 1/stress_lazy_compilation probability.
// Do this only for the main thread compilations because querying random
// numbers from background threads will make the random values dependent
// on the thread scheduling and thus non-deterministic.
stack_overflow_ = local_isolate_->fuzzer_rng()->NextInt(
v8_flags.stress_lazy_compilation) == 0;
}
// Initialize the incoming context.
ContextScope incoming_context(this, closure_scope());
// Initialize control scope.
ControlScopeForTopLevel control(this);
RegisterAllocationScope register_scope(this);
AllocateTopLevelRegisters();
builder()->EmitFunctionStartSourcePosition(
info()->literal()->start_position());
if (info()->literal()->CanSuspend()) {
BuildGeneratorPrologue();
}
if (NeedsContextInitialization(closure_scope())) {
// Push a new inner context scope for the function.
BuildNewLocalActivationContext();
ContextScope local_function_context(this, closure_scope());
BuildLocalActivationContextInitialization();
GenerateBytecodeBody();
} else {
GenerateBytecodeBody();
}
// Reset variables with hole check bitmap indices for subsequent compilations
// in the same parsing zone.
for (Variable* var : vars_in_hole_check_bitmap_) {
var->ResetHoleCheckBitmapIndex();
}
// Check that we are not falling off the end.
DCHECK(builder()->RemainderOfBlockIsDead());
}
void BytecodeGenerator::GenerateBytecodeBody() {
GenerateBodyPrologue();
if (IsBaseConstructor(function_kind())) {
GenerateBaseConstructorBody();
} else if (function_kind() == FunctionKind::kDerivedConstructor) {
GenerateDerivedConstructorBody();
} else if (IsAsyncFunction(function_kind()) ||
IsModuleWithTopLevelAwait(function_kind())) {
if (IsAsyncGeneratorFunction(function_kind())) {
GenerateAsyncGeneratorFunctionBody();
} else {
GenerateAsyncFunctionBody();
}
} else {
GenerateBodyStatements();
}
}
void BytecodeGenerator::GenerateBodyPrologue() {
// Build the arguments object if it is used.
VisitArgumentsObject(closure_scope()->arguments());
// Build rest arguments array if it is used.
Variable* rest_parameter = closure_scope()->rest_parameter();
VisitRestArgumentsArray(rest_parameter);
// Build assignment to the function name or {.this_function}
// variables if used.
VisitThisFunctionVariable(closure_scope()->function_var());
VisitThisFunctionVariable(closure_scope()->this_function_var());
// Build assignment to {new.target} variable if it is used.
VisitNewTargetVariable(closure_scope()->new_target_var());
// Create a generator object if necessary and initialize the
// {.generator_object} variable.
FunctionLiteral* literal = info()->literal();
if (IsResumableFunction(literal->kind())) {
BuildGeneratorObjectVariableInitialization();
}
// Emit tracing call if requested to do so.
if (v8_flags.trace) builder()->CallRuntime(Runtime::kTraceEnter);
// Increment the function-scope block coverage counter.
BuildIncrementBlockCoverageCounterIfEnabled(literal, SourceRangeKind::kBody);
// Visit declarations within the function scope.
if (closure_scope()->is_script_scope()) {
VisitGlobalDeclarations(closure_scope()->declarations());
} else if (closure_scope()->is_module_scope()) {
VisitModuleDeclarations(closure_scope()->declarations());
} else {
VisitDeclarations(closure_scope()->declarations());
}
// Emit initializing assignments for module namespace imports (if any).
VisitModuleNamespaceImports();
}
void BytecodeGenerator::GenerateBaseConstructorBody() {
DCHECK(IsBaseConstructor(function_kind()));
FunctionLiteral* literal = info()->literal();
// The derived constructor case is handled in VisitCallSuper.
if (literal->class_scope_has_private_brand()) {
ClassScope* scope = info()->scope()->outer_scope()->AsClassScope();
DCHECK_NOT_NULL(scope->brand());
BuildPrivateBrandInitialization(builder()->Receiver(), scope->brand());
}
if (literal->requires_instance_members_initializer()) {
BuildInstanceMemberInitialization(Register::function_closure(),
builder()->Receiver());
}
GenerateBodyStatements();
}
void BytecodeGenerator::GenerateDerivedConstructorBody() {
DCHECK_EQ(FunctionKind::kDerivedConstructor, function_kind());
FunctionLiteral* literal = info()->literal();
// Per spec, derived constructors can only return undefined or an object;
// other primitives trigger an exception in ConstructStub.
//
// Since the receiver is popped by the callee, derived constructors return
// <this> if the original return value was undefined.
//
// Also per spec, this return value check is done after all user code (e.g.,
// finally blocks) are executed. For example, the following code does not
// throw.
//
// class C extends class {} {
// constructor() {
// try { throw 42; }
// catch(e) { return; }
// finally { super(); }
// }
// }
// new C();
//
// This check is implemented by jumping to the check instead of emitting a
// return bytecode in-place inside derived constructors.
//
// Note that default derived constructors do not need this check as they
// just forward a super call.
BytecodeLabels check_return_value(zone());
Register result = register_allocator()->NewRegister();
ControlScopeForDerivedConstructor control(this, result, &check_return_value);
{
HoleCheckElisionScope elider(this);
GenerateBodyStatementsWithoutImplicitFinalReturn();
}
if (check_return_value.empty()) {
if (!builder()->RemainderOfBlockIsDead()) {
BuildThisVariableLoad();
BuildReturn(literal->return_position());
}
} else {
BytecodeLabels return_this(zone());
if (!builder()->RemainderOfBlockIsDead()) {
builder()->Jump(return_this.New());
}
check_return_value.Bind(builder());
builder()->LoadAccumulatorWithRegister(result);
builder()->JumpIfUndefined(return_this.New());
BuildReturn(literal->return_position());
{
return_this.Bind(builder());
BuildThisVariableLoad();
BuildReturn(literal->return_position());
}
}
}
void BytecodeGenerator::GenerateAsyncFunctionBody() {
DCHECK((IsAsyncFunction(function_kind()) &&
!IsAsyncGeneratorFunction(function_kind())) ||
IsModuleWithTopLevelAwait(function_kind()));
// Async functions always return promises. Return values fulfill that promise,
// while synchronously thrown exceptions reject that promise. This is handled
// by surrounding the body statements in a try-catch block as follows:
//
// try {
// <inner_block>
// } catch (.catch) {
// return %_AsyncFunctionReject(.generator_object, .catch);
// }
FunctionLiteral* literal = info()->literal();
HandlerTable::CatchPrediction outer_catch_prediction = catch_prediction();
// When compiling a REPL script, use UNCAUGHT_ASYNC_AWAIT to preserve the
// pending message so DevTools can inspect it.
set_catch_prediction(literal->scope()->is_repl_mode_scope()
? HandlerTable::UNCAUGHT_ASYNC_AWAIT
: HandlerTable::ASYNC_AWAIT);
BuildTryCatch(
[&]() {
GenerateBodyStatements();
set_catch_prediction(outer_catch_prediction);
},
[&](Register context) {
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(generator_object(), args[0])
.StoreAccumulatorInRegister(args[1]); // exception
if (!literal->scope()->is_repl_mode_scope()) {
builder()->LoadTheHole().SetPendingMessage();
}
builder()->CallRuntime(Runtime::kInlineAsyncFunctionReject, args);
// TODO(358404372): Should this return have a statement position?
// Without one it is not possible to apply a debugger breakpoint.
BuildReturn(kNoSourcePosition);
},
catch_prediction());
}
void BytecodeGenerator::GenerateAsyncGeneratorFunctionBody() {
DCHECK(IsAsyncGeneratorFunction(function_kind()));
set_catch_prediction(HandlerTable::ASYNC_AWAIT);
// For ES2017 Async Generators, we produce:
//
// try {
// InitialYield;
// ...body...;
// } catch (.catch) {
// %AsyncGeneratorReject(generator, .catch);
// } finally {
// %_GeneratorClose(generator);
// }
//
// - InitialYield yields the actual generator object.
// - Any return statement inside the body will have its argument wrapped
// in an iterator result object with a "done" property set to `true`.
// - If the generator terminates for whatever reason, we must close it.
// Hence the finally clause.
// - BytecodeGenerator performs special handling for ReturnStatements in
// async generator functions, resolving the appropriate Promise with an
// "done" iterator result object containing a Promise-unwrapped value.
// In async generator functions, when parameters are not simple,
// a parameter initialization block will be added as the first block to the
// AST. Since this block can throw synchronously, it should not be wrapped
// in the following try-finally. We visit this block outside the try-finally
// and remove it from the AST.
int start = 0;
ZonePtrList<Statement>* statements = info()->literal()->body();
Statement* stmt = statements->at(0);
if (stmt->IsBlock()) {
Block* block = static_cast<Block*>(statements->at(0));
if (block->is_initialization_block_for_parameters()) {
VisitBlockDeclarationsAndStatements(block);
start = 1;
}
}
BuildTryFinally(
[&]() {
BuildTryCatch(
[&]() { GenerateBodyStatements(start); },
[&](Register context) {
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(generator_object(), args[0])
.StoreAccumulatorInRegister(args[1]) // exception
.LoadTheHole()
.SetPendingMessage()
.CallRuntime(Runtime::kInlineAsyncGeneratorReject, args);
execution_control()->ReturnAccumulator(kNoSourcePosition);
},
catch_prediction());
},
[&](Register body_continuation_token, Register body_continuation_result,
Register message) {
RegisterAllocationScope register_scope(this);
Register arg = register_allocator()->NewRegister();
builder()
->MoveRegister(generator_object(), arg)
.CallRuntime(Runtime::kInlineGeneratorClose, arg);
},
catch_prediction());
}
void BytecodeGenerator::GenerateBodyStatements(int start) {
GenerateBodyStatementsWithoutImplicitFinalReturn(start);
// Emit an implicit return instruction in case control flow can fall off the
// end of the function without an explicit return being present on all paths.
//
// ControlScope is used instead of building the Return bytecode directly, as
// the entire body is wrapped in a try-finally block for async generators.
if (!builder()->RemainderOfBlockIsDead()) {
builder()->LoadUndefined();
const int pos = info()->literal()->return_position();
if (IsAsyncFunction(function_kind()) ||
IsModuleWithTopLevelAwait(function_kind())) {
execution_control()->AsyncReturnAccumulator(pos);
} else {
execution_control()->ReturnAccumulator(pos);
}
}
}
void BytecodeGenerator::GenerateBodyStatementsWithoutImplicitFinalReturn(
int start) {
ZonePtrList<Statement>* body = info()->literal()->body();
if (v8_flags.js_explicit_resource_management && closure_scope() != nullptr &&
(closure_scope()->has_using_declaration() ||
closure_scope()->has_await_using_declaration())) {
BuildDisposeScope([&]() { VisitStatements(body, start); },
closure_scope()->has_await_using_declaration());
} else {
VisitStatements(body, start);
}
}
void BytecodeGenerator::AllocateTopLevelRegisters() {
if (IsResumableFunction(info()->literal()->kind())) {
// Either directly use generator_object_var or allocate a new register for
// the incoming generator object.
Variable* generator_object_var = closure_scope()->generator_object_var();
if (generator_object_var->location() == VariableLocation::LOCAL) {
incoming_new_target_or_generator_ =
GetRegisterForLocalVariable(generator_object_var);
} else {
incoming_new_target_or_generator_ = register_allocator()->NewRegister();
}
} else if (closure_scope()->new_target_var()) {
// Either directly use new_target_var or allocate a new register for
// the incoming new target object.
Variable* new_target_var = closure_scope()->new_target_var();
if (new_target_var->location() == VariableLocation::LOCAL) {
incoming_new_target_or_generator_ =
GetRegisterForLocalVariable(new_target_var);
} else {
incoming_new_target_or_generator_ = register_allocator()->NewRegister();
}
}
}
void BytecodeGenerator::BuildGeneratorPrologue() {
DCHECK_GT(info()->literal()->suspend_count(), 0);
generator_jump_table_ =
builder()->AllocateJumpTable(info()->literal()->suspend_count(), 0);
// If the generator is not undefined, this is a resume, so perform state
// dispatch.
builder()->SwitchOnGeneratorState(generator_object(), generator_jump_table_);
// Otherwise, fall-through to the ordinary function prologue, after which we
// will run into the generator object creation and other extra code inserted
// by the parser.
}
void BytecodeGenerator::VisitBlock(Block* stmt) {
// Visit declarations and statements.
CurrentScope current_scope(this, stmt->scope());
if (stmt->scope() != nullptr && stmt->scope()->NeedsContext()) {
BuildNewLocalBlockContext(stmt->scope());
ContextScope scope(this, stmt->scope());
VisitBlockMaybeDispose(stmt);
} else {
VisitBlockMaybeDispose(stmt);
}
}
void BytecodeGenerator::VisitBlockMaybeDispose(Block* stmt) {
if (v8_flags.js_explicit_resource_management && stmt->scope() != nullptr &&
(stmt->scope()->has_using_declaration() ||
stmt->scope()->has_await_using_declaration())) {
BuildDisposeScope([&]() { VisitBlockDeclarationsAndStatements(stmt); },
stmt->scope()->has_await_using_declaration());
} else {
VisitBlockDeclarationsAndStatements(stmt);
}
}
void BytecodeGenerator::VisitBlockDeclarationsAndStatements(Block* stmt) {
BlockBuilder block_builder(builder(), block_coverage_builder_, stmt);
ControlScopeForBreakable execution_control(this, stmt, &block_builder);
if (stmt->scope() != nullptr) {
VisitDeclarations(stmt->scope()->declarations());
}
if (V8_UNLIKELY(stmt->is_breakable())) {
// Loathsome labeled blocks can be the target of break statements, which
// causes unconditional blocks to act conditionally, and therefore to
// require their own elision scope.
//
// lbl: {
// if (cond) break lbl;
// x;
// }
// x; <-- Cannot elide TDZ check
HoleCheckElisionScope elider(this);
VisitStatements(stmt->statements());
} else {
VisitStatements(stmt->statements());
}
}
void BytecodeGenerator::VisitVariableDeclaration(VariableDeclaration* decl) {
Variable* variable = decl->var();
// Unused variables don't need to be visited.
if (!variable->is_used()) return;
switch (variable->location()) {
case VariableLocation::UNALLOCATED:
case VariableLocation::MODULE:
UNREACHABLE();
case VariableLocation::LOCAL:
if (variable->binding_needs_init()) {
Register destination(builder()->Local(variable->index()));
builder()->LoadTheHole().StoreAccumulatorInRegister(destination);
}
break;
case VariableLocation::PARAMETER:
if (variable->binding_needs_init()) {
Register destination(builder()->Parameter(variable->index()));
builder()->LoadTheHole().StoreAccumulatorInRegister(destination);
}
break;
case VariableLocation::REPL_GLOBAL:
// REPL let's are stored in script contexts. They get initialized
// with the hole the same way as normal context allocated variables.
case VariableLocation::CONTEXT:
if (variable->binding_needs_init()) {
DCHECK_EQ(0, execution_context()->ContextChainDepth(variable->scope()));
builder()->LoadTheHole().StoreContextSlot(execution_context()->reg(),
variable, 0);
}
break;
case VariableLocation::LOOKUP: {
DCHECK_EQ(VariableMode::kDynamic, variable->mode());
DCHECK(!variable->binding_needs_init());
Register name = register_allocator()->NewRegister();
builder()
->LoadLiteral(variable->raw_name())
.StoreAccumulatorInRegister(name)
.CallRuntime(Runtime::kDeclareEvalVar, name);
break;
}
}
}
void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
Variable* variable = decl->var();
DCHECK(variable->mode() == VariableMode::kLet ||
variable->mode() == VariableMode::kVar ||
variable->mode() == VariableMode::kDynamic);
// Unused variables don't need to be visited.
if (!variable->is_used()) return;
switch (variable->location()) {
case VariableLocation::UNALLOCATED:
case VariableLocation::MODULE:
UNREACHABLE();
case VariableLocation::PARAMETER:
case VariableLocation::LOCAL: {
VisitFunctionLiteral(decl->fun());
BuildVariableAssignment(variable, Token::kInit, HoleCheckMode::kElided);
break;
}
case VariableLocation::REPL_GLOBAL:
case VariableLocation::CONTEXT: {
DCHECK_EQ(0, execution_context()->ContextChainDepth(variable->scope()));
VisitFunctionLiteral(decl->fun());
builder()->StoreContextSlot(execution_context()->reg(), variable, 0);
break;
}
case VariableLocation::LOOKUP: {
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->LoadLiteral(variable->raw_name())
.StoreAccumulatorInRegister(args[0]);
VisitFunctionLiteral(decl->fun());
builder()->StoreAccumulatorInRegister(args[1]).CallRuntime(
Runtime::kDeclareEvalFunction, args);
break;
}
}
DCHECK_IMPLIES(
eager_inner_literals_ != nullptr && decl->fun()->ShouldEagerCompile(),
IsInEagerLiterals(decl->fun(), *eager_inner_literals_));
}
void BytecodeGenerator::VisitModuleNamespaceImports() {
if (!closure_scope()->is_module_scope()) return;
RegisterAllocationScope register_scope(this);
Register module_request = register_allocator()->NewRegister();
SourceTextModuleDescriptor* descriptor =
closure_scope()->AsModuleScope()->module();
for (auto entry : descriptor->namespace_imports()) {
builder()
->LoadLiteral(Smi::FromInt(entry->module_request))
.StoreAccumulatorInRegister(module_request)
.CallRuntime(Runtime::kGetModuleNamespace, module_request);
Variable* var = closure_scope()->LookupInModule(entry->local_name);
BuildVariableAssignment(var, Token::kInit, HoleCheckMode::kElided);
}
}
void BytecodeGenerator::BuildDeclareCall(Runtime::FunctionId id) {
if (!top_level_builder()->has_top_level_declaration()) return;
DCHECK(!top_level_builder()->processed());
top_level_builder()->set_constant_pool_entry(
builder()->AllocateDeferredConstantPoolEntry());
// Emit code to declare globals.
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->LoadConstantPoolEntry(top_level_builder()->constant_pool_entry())
.StoreAccumulatorInRegister(args[0])
.MoveRegister(Register::function_closure(), args[1])
.CallRuntime(id, args);
top_level_builder()->mark_processed();
}
void BytecodeGenerator::VisitModuleDeclarations(Declaration::List* decls) {
RegisterAllocationScope register_scope(this);
for (Declaration* decl : *decls) {
Variable* var = decl->var();
if (!var->is_used()) continue;
if (var->location() == VariableLocation::MODULE) {
if (decl->IsFunctionDeclaration()) {
DCHECK(var->IsExport());
FunctionDeclaration* f = static_cast<FunctionDeclaration*>(decl);
AddToEagerLiteralsIfEager(f->fun());
top_level_builder()->record_module_function_declaration();
} else if (var->IsExport() && var->binding_needs_init()) {
DCHECK(decl->IsVariableDeclaration());
top_level_builder()->record_module_variable_declaration();
}
} else {
RegisterAllocationScope inner_register_scope(this);
Visit(decl);
}
}
BuildDeclareCall(Runtime::kDeclareModuleExports);
}
void BytecodeGenerator::VisitGlobalDeclarations(Declaration::List* decls) {
RegisterAllocationScope register_scope(this);
for (Declaration* decl : *decls) {
Variable* var = decl->var();
DCHECK(var->is_used());
if (var->location() == VariableLocation::UNALLOCATED) {
// var or function.
if (decl->IsFunctionDeclaration()) {
top_level_builder()->record_global_function_declaration();
FunctionDeclaration* f = static_cast<FunctionDeclaration*>(decl);
AddToEagerLiteralsIfEager(f->fun());
} else {
top_level_builder()->record_global_variable_declaration();
}
} else {
// let or const. Handled in NewScriptContext.
DCHECK(decl->IsVariableDeclaration());
DCHECK(IsLexicalVariableMode(var->mode()));
}
}
BuildDeclareCall(Runtime::kDeclareGlobals);
}
void BytecodeGenerator::VisitDeclarations(Declaration::List* declarations) {
for (Declaration* decl : *declarations) {
RegisterAllocationScope register_scope(this);
Visit(decl);
}
}
void BytecodeGenerator::VisitStatements(
const ZonePtrList<Statement>* statements, int start) {
for (int i = start; i < statements->length(); i++) {
// Allocate an outer register allocations scope for the statement.
RegisterAllocationScope allocation_scope(this);
Statement* stmt = statements->at(i);
Visit(stmt);
if (builder()->RemainderOfBlockIsDead()) break;
}
}
void BytecodeGenerator::VisitExpressionStatement(ExpressionStatement* stmt) {
builder()->SetStatementPosition(stmt);
VisitForEffect(stmt->expression());
}
void BytecodeGenerator::VisitEmptyStatement(EmptyStatement* stmt) {}
void BytecodeGenerator::VisitIfStatement(IfStatement* stmt) {
ConditionalControlFlowBuilder conditional_builder(
builder(), block_coverage_builder_, stmt);
builder()->SetStatementPosition(stmt);
if (stmt->condition()->ToBooleanIsTrue()) {
// Generate then block unconditionally as always true.
conditional_builder.Then();
Visit(stmt->then_statement());
} else if (stmt->condition()->ToBooleanIsFalse()) {
// Generate else block unconditionally if it exists.
if (stmt->HasElseStatement()) {
conditional_builder.Else();
Visit(stmt->else_statement());
}
} else {
// TODO(oth): If then statement is BreakStatement or
// ContinueStatement we can reduce number of generated
// jump/jump_ifs here. See BasicLoops test.
VisitForTest(stmt->condition(), conditional_builder.then_labels(),
conditional_builder.else_labels(), TestFallthrough::kThen);
HoleCheckElisionMergeScope merge_elider(this);
{
HoleCheckElisionMergeScope::Branch branch(merge_elider);
conditional_builder.Then();
Visit(stmt->then_statement());
}
{
HoleCheckElisionMergeScope::Branch branch(merge_elider);
if (stmt->HasElseStatement()) {
conditional_builder.JumpToEnd();
conditional_builder.Else();
Visit(stmt->else_statement());
}
}
merge_elider.Merge();
}
}
void BytecodeGenerator::VisitSloppyBlockFunctionStatement(
SloppyBlockFunctionStatement* stmt) {
Visit(stmt->statement());
}
void BytecodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
AllocateBlockCoverageSlotIfEnabled(stmt, SourceRangeKind::kContinuation);
builder()->SetStatementPosition(stmt);
execution_control()->Continue(stmt->target());
}
void BytecodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
AllocateBlockCoverageSlotIfEnabled(stmt, SourceRangeKind::kContinuation);
builder()->SetStatementPosition(stmt);
execution_control()->Break(stmt->target());
}
void BytecodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
AllocateBlockCoverageSlotIfEnabled(stmt, SourceRangeKind::kContinuation);
builder()->SetStatementPosition(stmt);
VisitForAccumulatorValue(stmt->expression());
int return_position = stmt->end_position();
if (return_position == ReturnStatement::kFunctionLiteralReturnPosition) {
return_position = info()->literal()->return_position();
}
if (stmt->is_async_return()) {
execution_control()->AsyncReturnAccumulator(return_position);
} else {
execution_control()->ReturnAccumulator(return_position);
}
}
void BytecodeGenerator::VisitWithStatement(WithStatement* stmt) {
builder()->SetStatementPosition(stmt);
VisitForAccumulatorValue(stmt->expression());
BuildNewLocalWithContext(stmt->scope());
VisitInScope(stmt->statement(), stmt->scope());
}
namespace {
bool IsSmiLiteralSwitchCaseValue(Expression* expr) {
if (expr->IsSmiLiteral() ||
(expr->IsLiteral() && expr->AsLiteral()->IsNumber() &&
expr->AsLiteral()->AsNumber() == 0.0)) {
return true;
#ifdef DEBUG
} else if (expr->IsLiteral() && expr->AsLiteral()->IsNumber()) {
DCHECK(!IsSmiDouble(expr->AsLiteral()->AsNumber()));
#endif
}
return false;
}
// Precondition: we called IsSmiLiteral to check this.
inline int ReduceToSmiSwitchCaseValue(Expression* expr) {
if (V8_LIKELY(expr->IsSmiLiteral())) {
return expr->AsLiteral()->AsSmiLiteral().value();
} else {
// Only the zero case is possible otherwise.
DCHECK(expr->IsLiteral() && expr->AsLiteral()->IsNumber() &&
expr->AsLiteral()->AsNumber() == -0.0);
return 0;
}
}
// Is the range of Smi's small enough relative to number of cases?
inline bool IsSpreadAcceptable(int spread, int ncases) {
return spread < v8_flags.switch_table_spread_threshold * ncases;
}
struct SwitchInfo {
static const int kDefaultNotFound = -1;
std::map<int, CaseClause*> covered_cases;
int default_case;
SwitchInfo() { default_case = kDefaultNotFound; }
bool DefaultExists() { return default_case != kDefaultNotFound; }
bool CaseExists(int j) {
return covered_cases.find(j) != covered_cases.end();
}
bool CaseExists(Expression* expr) {
return IsSmiLiteralSwitchCaseValue(expr)
? CaseExists(ReduceToSmiSwitchCaseValue(expr))
: false;
}
CaseClause* GetClause(int j) { return covered_cases[j]; }
bool IsDuplicate(CaseClause* clause) {
return IsSmiLiteralSwitchCaseValue(clause->label()) &&
CaseExists(clause->label()) &&
clause != GetClause(ReduceToSmiSwitchCaseValue(clause->label()));
}
int MinCase() {
return covered_cases.empty() ? INT_MAX : covered_cases.begin()->first;
}
int MaxCase() {
return covered_cases.empty() ? INT_MIN : covered_cases.rbegin()->first;
}
void Print() {
std::cout << "Covered_cases: " << '\n';
for (auto iter = covered_cases.begin(); iter != covered_cases.end();
++iter) {
std::cout << iter->first << "->" << iter->second << '\n';
}
std::cout << "Default_case: " << default_case << '\n';
}
};
// Checks whether we should use a jump table to implement a switch operation.
bool IsSwitchOptimizable(SwitchStatement* stmt, SwitchInfo* info) {
ZonePtrList<CaseClause>* cases = stmt->cases();
for (int i = 0; i < cases->length(); ++i) {
CaseClause* clause = cases->at(i);
if (clause->is_default()) {
continue;
} else if (!(clause->label()->IsLiteral())) {
// Don't consider Smi cases after a non-literal, because we
// need to evaluate the non-literal.
break;
} else if (IsSmiLiteralSwitchCaseValue(clause->label())) {
int value = ReduceToSmiSwitchCaseValue(clause->label());
info->covered_cases.insert({value, clause});
}
}
// GCC also jump-table optimizes switch statements with 6 cases or more.
if (static_cast<int>(info->covered_cases.size()) >=
v8_flags.switch_table_min_cases) {
// Due to case spread will be used as the size of jump-table,
// we need to check if it doesn't overflow by casting its
// min and max bounds to int64_t, and calculate if the difference is less
// than or equal to INT_MAX.
int64_t min = static_cast<int64_t>(info->MinCase());
int64_t max = static_cast<int64_t>(info->MaxCase());
int64_t spread = max - min + 1;
DCHECK_GT(spread, 0);
// Check if casted spread is acceptable and doesn't overflow.
if (spread <= INT_MAX &&
IsSpreadAcceptable(static_cast<int>(spread), cases->length())) {
return true;
}
}
// Invariant- covered_cases has all cases and only cases that will go in the
// jump table.
info->covered_cases.clear();
return false;
}
} // namespace
// This adds a jump table optimization for switch statements with Smi cases.
// If there are 5+ non-duplicate Smi clauses, and they are sufficiently compact,
// we generate a jump table. In the fall-through path, we put the compare-jumps
// for the non-Smi cases.
// e.g.
//
// switch(x){
// case -0: out = 10;
// case 1: out = 11; break;
// case 0: out = 12; break;
// case 2: out = 13;
// case 3: out = 14; break;
// case 0.5: out = 15; break;
// case 4: out = 16;
// case y: out = 17;
// case 5: out = 18;
// default: out = 19; break;
// }
// becomes this pseudo-bytecode:
// lda x
// star r1
// test_type number
// jump_if_false @fallthrough
// ldar r1
// test_greater_than_or_equal_to smi_min
// jump_if_false @fallthrough
// ldar r1
// test_less_than_or_equal_to smi_max
// jump_if_false @fallthrough
// ldar r1
// bitwise_or 0
// star r2
// test_strict_equal r1
// jump_if_false @fallthrough
// ldar r2
// switch_on_smi {1: @case_1, 2: @case_2, 3: @case_3, 4: @case_4}
// @fallthrough:
// jump_if_strict_equal -0.0 @case_minus_0.0
// jump_if_strict_equal 0.5 @case_0.5
// jump_if_strict_equal y @case_y
// jump_if_strict_equal 5 @case_5
// jump @default
// @case_minus_0.0:
// <out = 10>
// @case_1
// <out = 11, break>
// @case_0:
// <out = 12, break>
// @case_2:
// <out = 13>
// @case_3:
// <out = 14, break>
// @case_0.5:
// <out = 15, break>
// @case_4:
// <out = 16>
// @case_y:
// <out = 17>
// @case_5:
// <out = 18>
// @default:
// <out = 19, break>
void BytecodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
// We need this scope because we visit for register values. We have to
// maintain an execution result scope where registers can be allocated.
ZonePtrList<CaseClause>* clauses = stmt->cases();
SwitchInfo info;
BytecodeJumpTable* jump_table = nullptr;
bool use_jump_table = IsSwitchOptimizable(stmt, &info);
// N_comp_cases is number of cases we will generate comparison jumps for.
// Note we ignore duplicate cases, since they are very unlikely.
int n_comp_cases = clauses->length();
if (use_jump_table) {
n_comp_cases -= static_cast<int>(info.covered_cases.size());
jump_table = builder()->AllocateJumpTable(
info.MaxCase() - info.MinCase() + 1, info.MinCase());
}
// Are we still using any if-else bytecodes to evaluate the switch?
bool use_jumps = n_comp_cases != 0;
// Does the comparison for non-jump table jumps need an elision scope?
bool jump_comparison_needs_hole_check_elision_scope = false;
SwitchBuilder switch_builder(builder(), block_coverage_builder_, stmt,
n_comp_cases, jump_table);
ControlScopeForBreakable scope(this, stmt, &switch_builder);
builder()->SetStatementPosition(stmt);
VisitForAccumulatorValue(stmt->tag());
if (use_jump_table) {
// Release temps so that they can be reused in clauses.
RegisterAllocationScope allocation_scope(this);
// This also fills empty slots in jump table.
Register r2 = register_allocator()->NewRegister();
Register r1 = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(r1);
builder()->CompareTypeOf(TestTypeOfFlags::LiteralFlag::kNumber);
switch_builder.JumpToFallThroughIfFalse();
builder()->LoadAccumulatorWithRegister(r1);
// TODO(leszeks): Note these are duplicated range checks with the
// SwitchOnSmi handler for the most part.
builder()->LoadLiteral(Smi::kMinValue);
builder()->StoreAccumulatorInRegister(r2);
builder()->CompareOperation(
Token::kGreaterThanEq, r1,
feedback_index(feedback_spec()->AddCompareICSlot()));
switch_builder.JumpToFallThroughIfFalse();
builder()->LoadAccumulatorWithRegister(r1);
builder()->LoadLiteral(Smi::kMaxValue);
builder()->StoreAccumulatorInRegister(r2);
builder()->CompareOperation(
Token::kLessThanEq, r1,
feedback_index(feedback_spec()->AddCompareICSlot()));
switch_builder.JumpToFallThroughIfFalse();
builder()->LoadAccumulatorWithRegister(r1);
builder()->BinaryOperationSmiLiteral(
Token::kBitOr, Smi::FromInt(0),
feedback_index(feedback_spec()->AddBinaryOpICSlot()));
builder()->StoreAccumulatorInRegister(r2);
builder()->CompareOperation(
Token::kEqStrict, r1,
feedback_index(feedback_spec()->AddCompareICSlot()));
switch_builder.JumpToFallThroughIfFalse();
builder()->LoadAccumulatorWithRegister(r2);
switch_builder.EmitJumpTableIfExists(info.MinCase(), info.MaxCase(),
info.covered_cases);
if (use_jumps) {
// When using a jump table, the first jump comparison is conditionally
// executed if the discriminant wasn't matched by anything in the jump
// table, and so needs its own elision scope.
jump_comparison_needs_hole_check_elision_scope = true;
builder()->LoadAccumulatorWithRegister(r1);
}
}
int case_compare_ctr = 0;
#ifdef DEBUG
std::unordered_map<int, int> case_ctr_checker;
#endif
if (use_jumps) {
Register tag_holder = register_allocator()->NewRegister();
FeedbackSlot slot = clauses->length() > 0
? feedback_spec()->AddCompareICSlot()
: FeedbackSlot::Invalid();
builder()->StoreAccumulatorInRegister(tag_holder);
{
// The comparisons linearly dominate, so no need to open a new elision
// scope for each one.
std::optional<HoleCheckElisionScope> elider;
for (int i = 0; i < clauses->length(); ++i) {
CaseClause* clause = clauses->at(i);
if (clause->is_default()) {
info.default_case = i;
} else if (!info.CaseExists(clause->label())) {
if (jump_comparison_needs_hole_check_elision_scope && !elider) {
elider.emplace(this);
}
// Perform label comparison as if via '===' with tag.
VisitForAccumulatorValue(clause->label());
builder()->CompareOperation(Token::kEqStrict, tag_holder,
feedback_index(slot));
#ifdef DEBUG
case_ctr_checker[i] = case_compare_ctr;
#endif
switch_builder.JumpToCaseIfTrue(ToBooleanMode::kAlreadyBoolean,
case_compare_ctr++);
// The second and subsequent non-default comparisons are always
// conditionally executed, and need an elision scope.
jump_comparison_needs_hole_check_elision_scope = true;
}
}
}
register_allocator()->ReleaseRegister(tag_holder);
}
// For fall-throughs after comparisons (or out-of-range/non-Smi's for jump
// tables).
if (info.DefaultExists()) {
switch_builder.JumpToDefault();
} else {
switch_builder.Break();
}
// It is only correct to merge hole check states if there is a default clause,
// as otherwise it's unknown if the switch is exhaustive.
HoleCheckElisionMergeScope merge_elider(this);
case_compare_ctr = 0;
for (int i = 0; i < clauses->length(); ++i) {
CaseClause* clause = clauses->at(i);
if (i != info.default_case) {
if (!info.IsDuplicate(clause)) {
bool use_table = use_jump_table && info.CaseExists(clause->label());
if (!use_table) {
// Guarantee that we should generate compare/jump if no table.
#ifdef DEBUG
DCHECK(case_ctr_checker[i] == case_compare_ctr);
#endif
switch_builder.BindCaseTargetForCompareJump(case_compare_ctr++,
clause);
} else {
// Use jump table if this is not a duplicate label.
switch_builder.BindCaseTargetForJumpTable(
ReduceToSmiSwitchCaseValue(clause->label()), clause);
}
}
} else {
switch_builder.BindDefault(clause);
}
// Regardless, generate code (in case of fall throughs).
HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
VisitStatements(clause->statements());
}
merge_elider.MergeIf(info.DefaultExists());
}
template <typename TryBodyFunc, typename CatchBodyFunc>
void BytecodeGenerator::BuildTryCatch(
TryBodyFunc try_body_func, CatchBodyFunc catch_body_func,
HandlerTable::CatchPrediction catch_prediction,
TryCatchStatement* stmt_for_coverage) {
if (builder()->RemainderOfBlockIsDead()) return;
TryCatchBuilder try_control_builder(
builder(),
stmt_for_coverage == nullptr ? nullptr : block_coverage_builder_,
stmt_for_coverage, catch_prediction);
// Preserve the context in a dedicated register, so that it can be restored
// when the handler is entered by the stack-unwinding machinery.
// TODO(ignition): Be smarter about register allocation.
Register context = register_allocator()->NewRegister();
builder()->MoveRegister(Register::current_context(), context);
// Evaluate the try-block inside a control scope. This simulates a handler
// that is intercepting 'throw' control commands.
try_control_builder.BeginTry(context);
HoleCheckElisionMergeScope merge_elider(this);
{
ControlScopeForTryCatch scope(this, &try_control_builder);
// The try-block itself, even though unconditionally executed, can throw
// basically at any point, and so must be treated as conditional from the
// perspective of the hole check elision analysis.
//
// try { x } catch (e) { }
// use(x); <-- Still requires a TDZ check
//
// However, if both the try-block and the catch-block emit a hole check,
// subsequent TDZ checks can be elided.
//
// try { x; } catch (e) { x; }
// use(x); <-- TDZ check can be elided
HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
try_body_func();
}
try_control_builder.EndTry();
{
HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
catch_body_func(context);
}
merge_elider.Merge();
try_control_builder.EndCatch();
}
template <typename TryBodyFunc, typename FinallyBodyFunc>
void BytecodeGenerator::BuildTryFinally(
TryBodyFunc try_body_func, FinallyBodyFunc finally_body_func,
HandlerTable::CatchPrediction catch_prediction,
TryFinallyStatement* stmt_for_coverage) {
if (builder()->RemainderOfBlockIsDead()) return;
// We can't know whether the finally block will override ("catch") an
// exception thrown in the try block, so we just adopt the outer prediction.
TryFinallyBuilder try_control_builder(
builder(),
stmt_for_coverage == nullptr ? nullptr : block_coverage_builder_,
stmt_for_coverage, catch_prediction);
// We keep a record of all paths that enter the finally-block to be able to
// dispatch to the correct continuation point after the statements in the
// finally-block have been evaluated.
//
// The try-finally construct can enter the finally-block in three ways:
// 1. By exiting the try-block normally, falling through at the end.
// 2. By exiting the try-block with a function-local control flow transfer
// (i.e. through break/continue/return statements).
// 3. By exiting the try-block with a thrown exception.
//
// The result register semantics depend on how the block was entered:
// - ReturnStatement: It represents the return value being returned.
// - ThrowStatement: It represents the exception being thrown.
// - BreakStatement/ContinueStatement: Undefined and not used.
// - Falling through into finally-block: Undefined and not used.
Register token = register_allocator()->NewRegister();
Register result = register_allocator()->NewRegister();
Register message = register_allocator()->NewRegister();
builder()->LoadTheHole().StoreAccumulatorInRegister(message);
ControlScope::DeferredCommands commands(this, token, result, message);
// Preserve the context in a dedicated register, so that it can be restored
// when the handler is entered by the stack-unwinding machinery.
// TODO(ignition): Be smarter about register allocation.
Register context = register_allocator()->NewRegister();
builder()->MoveRegister(Register::current_context(), context);
// Evaluate the try-block inside a control scope. This simulates a handler
// that is intercepting all control commands.
try_control_builder.BeginTry(context);
{
ControlScopeForTryFinally scope(this, &try_control_builder, &commands);
// The try-block itself, even though unconditionally executed, can throw
// basically at any point, and so must be treated as conditional from the
// perspective of the hole check elision analysis.
HoleCheckElisionScope elider(this);
try_body_func();
}
try_control_builder.EndTry();
// Record fall-through and exception cases.
if (!builder()->RemainderOfBlockIsDead()) {
commands.RecordFallThroughPath();
}
try_control_builder.LeaveTry();
try_control_builder.BeginHandler();
commands.RecordHandlerReThrowPath();
try_control_builder.BeginFinally();
// Evaluate the finally-block.
finally_body_func(token, result, message);
try_control_builder.EndFinally();
// Dynamic dispatch after the finally-block.
commands.ApplyDeferredCommands();
}
template <typename WrappedFunc>
void BytecodeGenerator::BuildDisposeScope(WrappedFunc wrapped_func,
bool has_await_using) {
RegisterAllocationScope allocation_scope(this);
DisposablesStackScope disposables_stack_scope(this);
if (has_await_using) {
set_catch_prediction(info()->scope()->is_repl_mode_scope()
? HandlerTable::UNCAUGHT_ASYNC_AWAIT
: HandlerTable::ASYNC_AWAIT);
}
BuildTryFinally(
// Try block
[&]() { wrapped_func(); },
// Finally block
[&](Register body_continuation_token, Register body_continuation_result,
Register message) {
if (has_await_using) {
Register result_register = register_allocator()->NewRegister();
Register disposable_stack_register =
register_allocator()->NewRegister();
builder()->MoveRegister(current_disposables_stack(),
disposable_stack_register);
LoopBuilder loop_builder(builder(), nullptr, nullptr,
feedback_spec());
LoopScope loop_scope(this, &loop_builder);
{
RegisterAllocationScope allocation_scope(this);
RegisterList args = register_allocator()->NewRegisterList(5);
builder()
->MoveRegister(disposable_stack_register, args[0])
.MoveRegister(body_continuation_token, args[1])
.MoveRegister(body_continuation_result, args[2])
.MoveRegister(message, args[3])
.LoadLiteral(Smi::FromEnum(
DisposableStackResourcesType::kAtLeastOneAsync))
.StoreAccumulatorInRegister(args[4]);
builder()->CallRuntime(Runtime::kDisposeDisposableStack, args);
}
builder()
->StoreAccumulatorInRegister(result_register)
.LoadTrue()
.CompareReference(result_register);
loop_builder.BreakIfTrue(ToBooleanMode::kConvertToBoolean);
builder()->LoadAccumulatorWithRegister(result_register);
BuildTryCatch(
[&]() { BuildAwait(); },
[&](Register context) {
RegisterList args = register_allocator()->NewRegisterList(3);
builder()
->MoveRegister(current_disposables_stack(), args[0])
.StoreAccumulatorInRegister(args[1]) // exception
.LoadTheHole()
.SetPendingMessage()
.StoreAccumulatorInRegister(args[2])
.CallRuntime(
Runtime::kHandleExceptionsInDisposeDisposableStack,
args);
builder()->StoreAccumulatorInRegister(
disposable_stack_register);
},
catch_prediction());
loop_builder.BindContinueTarget();
} else {
RegisterList args = register_allocator()->NewRegisterList(5);
builder()
->MoveRegister(current_disposables_stack(), args[0])
.MoveRegister(body_continuation_token, args[1])
.MoveRegister(body_continuation_result, args[2])
.MoveRegister(message, args[3])
.LoadLiteral(
Smi::FromEnum(DisposableStackResourcesType::kAllSync))
.StoreAccumulatorInRegister(args[4]);
builder()->CallRuntime(Runtime::kDisposeDisposableStack, args);
}
},
catch_prediction());
}
void BytecodeGenerator::VisitIterationBody(IterationStatement* stmt,
LoopBuilder* loop_builder) {
loop_builder->LoopBody();
ControlScopeForIteration execution_control(this, stmt, loop_builder);
Visit(stmt->body());
loop_builder->BindContinueTarget();
}
void BytecodeGenerator::VisitIterationBodyInHoleCheckElisionScope(
IterationStatement* stmt, LoopBuilder* loop_builder) {
HoleCheckElisionScope elider(this);
VisitIterationBody(stmt, loop_builder);
}
void BytecodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
LoopBuilder loop_builder(builder(), block_coverage_builder_, stmt,
feedback_spec());
if (stmt->cond()->ToBooleanIsFalse()) {
// Since we know that the condition is false, we don't create a loop.
// Therefore, we don't create a LoopScope (and thus we don't create a header
// and a JumpToHeader). However, we still need to iterate once through the
// body.
VisitIterationBodyInHoleCheckElisionScope(stmt, &loop_builder);
} else if (stmt->cond()->ToBooleanIsTrue()) {
LoopScope loop_scope(this, &loop_builder);
VisitIterationBodyInHoleCheckElisionScope(stmt, &loop_builder);
} else {
LoopScope loop_scope(this, &loop_builder);
VisitIterationBodyInHoleCheckElisionScope(stmt, &loop_builder);
builder()->SetExpressionAsStatementPosition(stmt->cond());
BytecodeLabels loop_backbranch(zone());
if (!loop_builder.break_labels()->empty()) {
// The test may be conditionally executed if there was a break statement
// inside the loop body, and therefore requires its own elision scope.
HoleCheckElisionScope elider(this);
VisitForTest(stmt->cond(), &loop_backbranch, loop_builder.break_labels(),
TestFallthrough::kThen);
} else {
VisitForTest(stmt->cond(), &loop_backbranch, loop_builder.break_labels(),
TestFallthrough::kThen);
}
loop_backbranch.Bind(builder());
}
}
void BytecodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
LoopBuilder loop_builder(builder(), block_coverage_builder_, stmt,
feedback_spec());
if (stmt->cond()->ToBooleanIsFalse()) {
// If the condition is false there is no need to generate the loop.
return;
}
LoopScope loop_scope(this, &loop_builder);
if (!stmt->cond()->ToBooleanIsTrue()) {
builder()->SetExpressionAsStatementPosition(stmt->cond());
BytecodeLabels loop_body(zone());
VisitForTest(stmt->cond(), &loop_body, loop_builder.break_labels(),
TestFallthrough::kThen);
loop_body.Bind(builder());
}
VisitIterationBodyInHoleCheckElisionScope(stmt, &loop_builder);
}
void BytecodeGenerator::VisitForStatement(ForStatement* stmt) {
if (stmt->init() != nullptr) {
Visit(stmt->init());
}
LoopBuilder loop_builder(builder(), block_coverage_builder_, stmt,
feedback_spec());
if (stmt->cond() && stmt->cond()->ToBooleanIsFalse()) {
// If the condition is known to be false there is no need to generate
// body, next or condition blocks. Init block should be generated.
return;
}
LoopScope loop_scope(this, &loop_builder);
if (stmt->cond() && !stmt->cond()->ToBooleanIsTrue()) {
builder()->SetExpressionAsStatementPosition(stmt->cond());
BytecodeLabels loop_body(zone());
VisitForTest(stmt->cond(), &loop_body, loop_builder.break_labels(),
TestFallthrough::kThen);
loop_body.Bind(builder());
}
// C-style for loops' textual order differs from dominator order.
//
// for (INIT; TEST; NEXT) BODY
// REST
//
// has the dominator order of
//
// INIT dominates TEST dominates BODY dominates NEXT
// and
// INIT dominates TEST dominates REST
//
// INIT and TEST are always evaluated and so do not have their own
// HoleCheckElisionScope. BODY, like all iteration bodies, can contain control
// flow like breaks or continues, has its own HoleCheckElisionScope. NEXT is
// therefore conditionally evaluated and also so has its own
// HoleCheckElisionScope.
HoleCheckElisionScope elider(this);
VisitIterationBody(stmt, &loop_builder);
if (stmt->next() != nullptr) {
builder()->SetStatementPosition(stmt->next());
Visit(stmt->next());
}
}
void BytecodeGenerator::VisitForInStatement(ForInStatement* stmt) {
if (stmt->subject()->IsNullLiteral() ||
stmt->subject()->IsUndefinedLiteral()) {
// ForIn generates lots of code, skip if it wouldn't produce any effects.
return;
}
BytecodeLabel subject_undefined_label;
FeedbackSlot slot = feedback_spec()->AddForInSlot();
// Prepare the state for executing ForIn.
builder()->SetExpressionAsStatementPosition(stmt->subject());
{
CurrentScope current_scope(this, stmt->subject_scope());
VisitForAccumulatorValue(stmt->subject());
}
builder()->JumpIfUndefinedOrNull(&subject_undefined_label);
Register receiver = register_allocator()->NewRegister();
builder()->ToObject(receiver);
// Used as kRegTriple and kRegPair in ForInPrepare and ForInNext.
RegisterList triple = register_allocator()->NewRegisterList(3);
Register cache_length = triple[2];
builder()->ForInEnumerate(receiver);
builder()->ForInPrepare(triple, feedback_index(slot));
// Set up loop counter
Register index = register_allocator()->NewRegister();
builder()->LoadLiteral(Smi::zero());
builder()->StoreAccumulatorInRegister(index);
// The loop
{
LoopBuilder loop_builder(builder(), block_coverage_builder_, stmt,
feedback_spec());
LoopScope loop_scope(this, &loop_builder);
HoleCheckElisionScope elider(this);
builder()->SetExpressionAsStatementPosition(stmt->each());
loop_builder.BreakIfForInDone(index, cache_length);
builder()->ForInNext(receiver, index, triple.Truncate(2),
feedback_index(slot));
loop_builder.ContinueIfUndefined();
// Assign accumulator value to the 'each' target.
{
EffectResultScope scope(this);
// Make sure to preserve the accumulator across the PrepareAssignmentLhs
// call.
AssignmentLhsData lhs_data = PrepareAssignmentLhs(
stmt->each(), AccumulatorPreservingMode::kPreserve);
builder()->SetExpressionPosition(stmt->each());
BuildAssignment(lhs_data, Token::kAssign, LookupHoistingMode::kNormal);
}
{
Register cache_type = triple[0];
ForInScope scope(this, stmt, index, cache_type);
VisitIterationBody(stmt, &loop_builder);
builder()->ForInStep(index);
}
}
builder()->Bind(&subject_undefined_label);
}
// Desugar a for-of statement into an application of the iteration protocol.
//
// for (EACH of SUBJECT) BODY
//
// becomes
//
// iterator = %GetIterator(SUBJECT)
// try {
//
// loop {
// // Make sure we are considered 'done' if .next(), .done or .value fail.
// done = true
// value = iterator.next()
// if (value.done) break;
// value = value.value
// done = false
//
// EACH = value
// BODY
// }
// done = true
//
// } catch(e) {
// iteration_continuation = RETHROW
// } finally {
// %FinalizeIteration(iterator, done, iteration_continuation)
// }
void BytecodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
EffectResultScope effect_scope(this);
builder()->SetExpressionAsStatementPosition(stmt->subject());
{
CurrentScope current_scope(this, stmt->subject_scope());
VisitForAccumulatorValue(stmt->subject());
}
// Store the iterator in a dedicated register so that it can be closed on
// exit, and the 'done' value in a dedicated register so that it can be
// changed and accessed independently of the iteration result.
IteratorRecord iterator = BuildGetIteratorRecord(stmt->type());
Register done = register_allocator()->NewRegister();
builder()->LoadFalse();
builder()->StoreAccumulatorInRegister(done);
BuildTryFinally(
// Try block.
[&]() {
LoopBuilder loop_builder(builder(), block_coverage_builder_, stmt,
feedback_spec());
LoopScope loop_scope(this, &loop_builder);
// This doesn't need a HoleCheckElisionScope because BuildTryFinally
// already makes one for try blocks.
builder()->LoadTrue().StoreAccumulatorInRegister(done);
{
RegisterAllocationScope allocation_scope(this);
Register next_result = register_allocator()->NewRegister();
// Call the iterator's .next() method. Break from the loop if the
// `done` property is truthy, otherwise load the value from the
// iterator result and append the argument.
builder()->SetExpressionAsStatementPosition(stmt->each());
BuildIteratorNext(iterator, next_result);
builder()->LoadNamedProperty(
next_result, ast_string_constants()->done_string(),
feedback_index(feedback_spec()->AddLoadICSlot()));
loop_builder.BreakIfTrue(ToBooleanMode::kConvertToBoolean);
builder()
// value = value.value
->LoadNamedProperty(
next_result, ast_string_constants()->value_string(),
feedback_index(feedback_spec()->AddLoadICSlot()));
// done = false, before the assignment to each happens, so that done
// is false if the assignment throws.
builder()
->StoreAccumulatorInRegister(next_result)
.LoadFalse()
.StoreAccumulatorInRegister(done);
// Assign to the 'each' target.
AssignmentLhsData lhs_data = PrepareAssignmentLhs(stmt->each());
builder()->LoadAccumulatorWithRegister(next_result);
BuildAssignment(lhs_data, Token::kAssign,
LookupHoistingMode::kNormal);
}
VisitIterationBody(stmt, &loop_builder);
},
// Finally block.
[&](Register iteration_continuation_token,
Register iteration_continuation_result, Register message) {
// Finish the iteration in the finally block.
BuildFinalizeIteration(iterator, done, iteration_continuation_token);
},
catch_prediction());
}
void BytecodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
// Update catch prediction tracking. The updated catch_prediction value lasts
// until the end of the try_block in the AST node, and does not apply to the
// catch_block.
HandlerTable::CatchPrediction outer_catch_prediction = catch_prediction();
set_catch_prediction(stmt->GetCatchPrediction(outer_catch_prediction));
BuildTryCatch(
// Try body.
[&]() {
Visit(stmt->try_block());
set_catch_prediction(outer_catch_prediction);
},
// Catch body.
[&](Register context) {
if (stmt->scope()) {
// Create a catch scope that binds the exception.
BuildNewLocalCatchContext(stmt->scope());
builder()->StoreAccumulatorInRegister(context);
}
// If requested, clear message object as we enter the catch block.
if (stmt->ShouldClearException(outer_catch_prediction)) {
builder()->LoadTheHole().SetPendingMessage();
}
// Load the catch context into the accumulator.
builder()->LoadAccumulatorWithRegister(context);
// Evaluate the catch-block.
if (stmt->scope()) {
VisitInScope(stmt->catch_block(), stmt->scope());
} else {
VisitBlock(stmt->catch_block());
}
},
catch_prediction(), stmt);
}
void BytecodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
BuildTryFinally(
// Try block.
[&]() { Visit(stmt->try_block()); },
// Finally block.
[&](Register body_continuation_token, Register body_continuation_result,
Register message) { Visit(stmt->finally_block()); },
catch_prediction(), stmt);
}
void BytecodeGenerator::VisitDebuggerStatement(DebuggerStatement* stmt) {
builder()->SetStatementPosition(stmt);
builder()->Debugger();
}
void BytecodeGenerator::VisitFunctionLiteral(FunctionLiteral* expr) {
CHECK_LT(info_->literal()->function_literal_id(),
expr->function_literal_id());
DCHECK_EQ(expr->scope()->outer_scope(), current_scope());
uint8_t flags = CreateClosureFlags::Encode(
expr->pretenure(), closure_scope()->is_function_scope(),
info()->flags().might_always_turbofan());
size_t entry = builder()->AllocateDeferredConstantPoolEntry();
builder()->CreateClosure(entry, GetCachedCreateClosureSlot(expr), flags);
function_literals_.push_back(std::make_pair(expr, entry));
AddToEagerLiteralsIfEager(expr);
}
void BytecodeGenerator::AddToEagerLiteralsIfEager(FunctionLiteral* literal) {
// Only parallel compile when there's a script (not the case for source
// position collection).
if (!script_.is_null() && literal->should_parallel_compile()) {
// If we should normally be eagerly compiling this function, we must be here
// because of post_parallel_compile_tasks_for_eager_toplevel.
DCHECK_IMPLIES(
literal->ShouldEagerCompile(),
info()->flags().post_parallel_compile_tasks_for_eager_toplevel());
// There exists a lazy compile dispatcher.
DCHECK(info()->dispatcher());
// There exists a cloneable character stream.
DCHECK(info()->character_stream()->can_be_cloned_for_parallel_access());
UnparkedScopeIfOnBackground scope(local_isolate_);
// If there doesn't already exist a SharedFunctionInfo for this function,
// then create one and enqueue it. Otherwise, we're reparsing (e.g. for the
// debugger, source position collection, call printing, recompile after
// flushing, etc.) and don't want to over-compile.
DirectHandle<SharedFunctionInfo> shared_info =
Compiler::GetSharedFunctionInfo(literal, script_, local_isolate_);
if (!shared_info->is_compiled()) {
info()->dispatcher()->Enqueue(
local_isolate_, indirect_handle(shared_info, local_isolate_),
info()->character_stream()->Clone());
}
} else if (eager_inner_literals_ && literal->ShouldEagerCompile()) {
DCHECK(!IsInEagerLiterals(literal, *eager_inner_literals_));
DCHECK(!literal->should_parallel_compile());
eager_inner_literals_->push_back(literal);
}
}
void BytecodeGenerator::BuildClassLiteral(ClassLiteral* expr, Register name) {
size_t class_boilerplate_entry =
builder()->AllocateDeferredConstantPoolEntry();
class_literals_.push_back(std::make_pair(expr, class_boilerplate_entry));
VisitDeclarations(expr->scope()->declarations());
Register class_constructor = register_allocator()->NewRegister();
// Create the class brand symbol and store it on the context during class
// evaluation. This will be stored in the instance later in the constructor.
// We do this early so that invalid access to private methods or accessors
// in computed property keys throw.
if (expr->scope()->brand() != nullptr) {
Register brand = register_allocator()->NewRegister();
const AstRawString* class_name =
expr->scope()->class_variable() != nullptr
? expr->scope()->class_variable()->raw_name()
: ast_string_constants()->anonymous_string();
builder()
->LoadLiteral(class_name)
.StoreAccumulatorInRegister(brand)
.CallRuntime(Runtime::kCreatePrivateBrandSymbol, brand);
register_allocator()->ReleaseRegister(brand);
BuildVariableAssignment(expr->scope()->brand(), Token::kInit,
HoleCheckMode::kElided);
}
AccessorTable<ClassLiteral::Property> private_accessors(zone());
for (int i = 0; i < expr->private_members()->length(); i++) {
ClassLiteral::Property* property = expr->private_members()->at(i);
DCHECK(property->is_private());
switch (property->kind()) {
case ClassLiteral::Property::FIELD: {
// Initialize the private field variables early.
// Create the private name symbols for fields during class
// evaluation and store them on the context. These will be
// used as keys later during instance or static initialization.
RegisterAllocationScope private_name_register_scope(this);
Register private_name = register_allocator()->NewRegister();
VisitForRegisterValue(property->key(), private_name);
builder()
->LoadLiteral(property->key()->AsLiteral()->AsRawPropertyName())
.StoreAccumulatorInRegister(private_name)
.CallRuntime(Runtime::kCreatePrivateNameSymbol, private_name);
DCHECK_NOT_NULL(property->private_name_var());
BuildVariableAssignment(property->private_name_var(), Token::kInit,
HoleCheckMode::kElided);
break;
}
case ClassLiteral::Property::METHOD: {
RegisterAllocationScope register_scope(this);
VisitForAccumulatorValue(property->value());
BuildVariableAssignment(property->private_name_var(), Token::kInit,
HoleCheckMode::kElided);
break;
}
// Collect private accessors into a table to merge the creation of
// those closures later.
case ClassLiteral::Property::GETTER: {
Literal* key = property->key()->AsLiteral();
DCHECK_NULL(private_accessors.LookupOrInsert(key)->getter);
private_accessors.LookupOrInsert(key)->getter = property;
break;
}
case ClassLiteral::Property::SETTER: {
Literal* key = property->key()->AsLiteral();
DCHECK_NULL(private_accessors.LookupOrInsert(key)->setter);
private_accessors.LookupOrInsert(key)->setter = property;
break;
}
case ClassLiteral::Property::AUTO_ACCESSOR: {
Literal* key = property->key()->AsLiteral();
RegisterAllocationScope private_name_register_scope(this);
Register accessor_storage_private_name =
register_allocator()->NewRegister();
Variable* accessor_storage_private_name_var =
property->auto_accessor_info()
->accessor_storage_name_proxy()
->var();
// We reuse the already internalized
// ".accessor-storage-<accessor_number>" strings that were defined in
// the parser instead of the "<name>accessor storage" string from the
// spec. The downsides are that is that these are the property names
// that will show up in devtools and in error messages.
// Additionally, a property can share a name with the corresponding
// property of their parent class, i.e. for classes defined as
// "class C {accessor x}" and "class D extends C {accessor y}",
// if "d = new D()", then d.x and d.y will share the name
// ".accessor-storage-0", (but a different private symbol).
// TODO(42202709): Get to a resolution on how to handle this naming
// issue before shipping the feature.
builder()
->LoadLiteral(accessor_storage_private_name_var->raw_name())
.StoreAccumulatorInRegister(accessor_storage_private_name)
.CallRuntime(Runtime::kCreatePrivateNameSymbol,
accessor_storage_private_name);
BuildVariableAssignment(accessor_storage_private_name_var, Token::kInit,
HoleCheckMode::kElided);
auto* accessor_pair = private_accessors.LookupOrInsert(key);
DCHECK_NULL(accessor_pair->getter);
accessor_pair->getter = property;
DCHECK_NULL(accessor_pair->setter);
accessor_pair->setter = property;
break;
}
default:
UNREACHABLE();
}
}
{
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewGrowableRegisterList();
Register class_boilerplate = register_allocator()->GrowRegisterList(&args);
Register class_constructor_in_args =
register_allocator()->GrowRegisterList(&args);
Register super_class = register_allocator()->GrowRegisterList(&args);
DCHECK_EQ(ClassBoilerplate::kFirstDynamicArgumentIndex,
args.register_count());
VisitForAccumulatorValueOrTheHole(expr->extends());
builder()->StoreAccumulatorInRegister(super_class);
VisitFunctionLiteral(expr->constructor());
builder()
->StoreAccumulatorInRegister(class_constructor)
.MoveRegister(class_constructor, class_constructor_in_args)
.LoadConstantPoolEntry(class_boilerplate_entry)
.StoreAccumulatorInRegister(class_boilerplate);
// Create computed names and method values nodes to store into the literal.
for (int i = 0; i < expr->public_members()->length(); i++) {
ClassLiteral::Property* property = expr->public_members()->at(i);
if (property->is_computed_name()) {
Register key = register_allocator()->GrowRegisterList(&args);
builder()->SetExpressionAsStatementPosition(property->key());
BuildLoadPropertyKey(property, key);
if (property->is_static()) {
// The static prototype property is read only. We handle the non
// computed property name case in the parser. Since this is the only
// case where we need to check for an own read only property we
// special case this so we do not need to do this for every property.
FeedbackSlot slot = GetDummyCompareICSlot();
BytecodeLabel done;
builder()
->LoadLiteral(ast_string_constants()->prototype_string())
.CompareOperation(Token::kEqStrict, key, feedback_index(slot))
.JumpIfFalse(ToBooleanMode::kAlreadyBoolean, &done)
.CallRuntime(Runtime::kThrowStaticPrototypeError)
.Bind(&done);
}
if (property->kind() == ClassLiteral::Property::FIELD) {
DCHECK(!property->is_private());
// Initialize field's name variable with the computed name.
DCHECK_NOT_NULL(property->computed_name_var());
builder()->LoadAccumulatorWithRegister(key);
BuildVariableAssignment(property->computed_name_var(), Token::kInit,
HoleCheckMode::kElided);
}
}
DCHECK(!property->is_private());
if (property->kind() == ClassLiteral::Property::FIELD) {
// We don't compute field's value here, but instead do it in the
// initializer function.
continue;
}
if (property->kind() == ClassLiteral::Property::AUTO_ACCESSOR) {
{
RegisterAllocationScope private_name_register_scope(this);
Register name_register = register_allocator()->NewRegister();
Variable* accessor_storage_private_name_var =
property->auto_accessor_info()
->accessor_storage_name_proxy()
->var();
builder()
->LoadLiteral(accessor_storage_private_name_var->raw_name())
.StoreAccumulatorInRegister(name_register)
.CallRuntime(Runtime::kCreatePrivateNameSymbol, name_register);
BuildVariableAssignment(accessor_storage_private_name_var,
Token::kInit, HoleCheckMode::kElided);
}
Register getter = register_allocator()->GrowRegisterList(&args);
Register setter = register_allocator()->GrowRegisterList(&args);
AutoAccessorInfo* auto_accessor_info = property->auto_accessor_info();
VisitForRegisterValue(auto_accessor_info->generated_getter(), getter);
VisitForRegisterValue(auto_accessor_info->generated_setter(), setter);
continue;
}
Register value = register_allocator()->GrowRegisterList(&args);
VisitForRegisterValue(property->value(), value);
}
builder()->CallRuntime(Runtime::kDefineClass, args);
}
// Assign to the home object variable. Accumulator already contains the
// prototype.
Variable* home_object_variable = expr->home_object();
if (home_object_variable != nullptr) {
DCHECK(home_object_variable->is_used());
DCHECK(home_object_variable->IsContextSlot());
BuildVariableAssignment(home_object_variable, Token::kInit,
HoleCheckMode::kElided);
}
Variable* static_home_object_variable = expr->static_home_object();
if (static_home_object_variable != nullptr) {
DCHECK(static_home_object_variable->is_used());
DCHECK(static_home_object_variable->IsContextSlot());
builder()->LoadAccumulatorWithRegister(class_constructor);
BuildVariableAssignment(static_home_object_variable, Token::kInit,
HoleCheckMode::kElided);
}
// Assign to class variable.
Variable* class_variable = expr->scope()->class_variable();
if (class_variable != nullptr && class_variable->is_used()) {
DCHECK(class_variable->IsStackLocal() || class_variable->IsContextSlot());
builder()->LoadAccumulatorWithRegister(class_constructor);
BuildVariableAssignment(class_variable, Token::kInit,
HoleCheckMode::kElided);
}
// Define private accessors, using only a single call to the runtime for
// each pair of corresponding getters and setters, in the order the first
// component is declared.
for (auto accessors : private_accessors.ordered_accessors()) {
RegisterAllocationScope inner_register_scope(this);
RegisterList accessors_reg = register_allocator()->NewRegisterList(2);
ClassLiteral::Property* getter = accessors.second->getter;
ClassLiteral::Property* setter = accessors.second->setter;
Variable* accessor_pair_var;
if (getter && getter->kind() == ClassLiteral::Property::AUTO_ACCESSOR) {
DCHECK_EQ(setter, getter);
AutoAccessorInfo* auto_accessor_info = getter->auto_accessor_info();
VisitForRegisterValue(auto_accessor_info->generated_getter(),
accessors_reg[0]);
VisitForRegisterValue(auto_accessor_info->generated_setter(),
accessors_reg[1]);
accessor_pair_var =
auto_accessor_info->property_private_name_proxy()->var();
} else {
VisitLiteralAccessor(getter, accessors_reg[0]);
VisitLiteralAccessor(setter, accessors_reg[1]);
accessor_pair_var = getter != nullptr ? getter->private_name_var()
: setter->private_name_var();
}
builder()->CallRuntime(Runtime::kCreatePrivateAccessors, accessors_reg);
DCHECK_NOT_NULL(accessor_pair_var);
BuildVariableAssignment(accessor_pair_var, Token::kInit,
HoleCheckMode::kElided);
}
if (expr->instance_members_initializer_function() != nullptr) {
VisitForAccumulatorValue(expr->instance_members_initializer_function());
FeedbackSlot slot = feedback_spec()->AddStoreICSlot(language_mode());
builder()
->StoreClassFieldsInitializer(class_constructor, feedback_index(slot))
.LoadAccumulatorWithRegister(class_constructor);
}
if (expr->static_initializer() != nullptr) {
// TODO(gsathya): This can be optimized away to be a part of the
// class boilerplate in the future. The name argument can be
// passed to the DefineClass runtime function and have it set
// there.
// TODO(v8:13451): Alternatively, port SetFunctionName to an ic so that we
// can replace the runtime call to a dedicate bytecode here.
if (name.is_valid()) {
RegisterAllocationScope inner_register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(class_constructor, args[0])
.MoveRegister(name, args[1])
.CallRuntime(Runtime::kSetFunctionName, args);
}
RegisterAllocationScope inner_register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(1);
Register initializer = VisitForRegisterValue(expr->static_initializer());
builder()
->MoveRegister(class_constructor, args[0])
.CallProperty(initializer, args,
feedback_index(feedback_spec()->AddCallICSlot()));
}
builder()->LoadAccumulatorWithRegister(class_constructor);
}
void BytecodeGenerator::VisitClassLiteral(ClassLiteral* expr) {
VisitClassLiteral(expr, Register::invalid_value());
}
void BytecodeGenerator::VisitClassLiteral(ClassLiteral* expr, Register name) {
CurrentScope current_scope(this, expr->scope());
DCHECK_NOT_NULL(expr->scope());
if (expr->scope()->NeedsContext()) {
// Make sure to associate the source position for the class
// after the block context is created. Otherwise we have a mismatch
// between the scope and the context, where we already are in a
// block context for the class, but not yet in the class scope. Only do
// this if the current source position is inside the class scope though.
// For example:
// * `var x = class {};` will break on `class` which is inside
// the class scope, so we expect the BlockContext to be pushed.
//
// * `new class x {};` will break on `new` which is outside the
// class scope, so we expect the BlockContext to not be pushed yet.
std::optional<BytecodeSourceInfo> source_info =
builder()->MaybePopSourcePosition(expr->scope()->start_position());
BuildNewLocalBlockContext(expr->scope());
ContextScope scope(this, expr->scope());
if (source_info) builder()->PushSourcePosition(*source_info);
BuildClassLiteral(expr, name);
} else {
BuildClassLiteral(expr, name);
}
}
void BytecodeGenerator::BuildClassProperty(ClassLiteral::Property* property) {
RegisterAllocationScope register_scope(this);
Register key;
// Private methods are not initialized in BuildClassProperty.
DCHECK_IMPLIES(property->is_private(),
property->kind() == ClassLiteral::Property::FIELD ||
property->is_auto_accessor());
builder()->SetExpressionPosition(property->key());
bool is_literal_store =
property->key()->IsPropertyName() && !property->is_computed_name() &&
!property->is_private() && !property->is_auto_accessor();
if (!is_literal_store) {
key = register_allocator()->NewRegister();
if (property->is_auto_accessor()) {
Variable* var =
property->auto_accessor_info()->accessor_storage_name_proxy()->var();
DCHECK_NOT_NULL(var);
BuildVariableLoad(var, HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(key);
} else if (property->is_computed_name()) {
DCHECK_EQ(property->kind(), ClassLiteral::Property::FIELD);
DCHECK(!property->is_private());
Variable* var = property->computed_name_var();
DCHECK_NOT_NULL(var);
// The computed name is already evaluated and stored in a variable at
// class definition time.
BuildVariableLoad(var, HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(key);
} else if (property->is_private()) {
Variable* private_name_var = property->private_name_var();
DCHECK_NOT_NULL(private_name_var);
BuildVariableLoad(private_name_var, HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(key);
} else {
VisitForRegisterValue(property->key(), key);
}
}
builder()->SetExpressionAsStatementPosition(property->value());
if (is_literal_store) {
VisitForAccumulatorValue(property->value());
FeedbackSlot slot = feedback_spec()->AddDefineNamedOwnICSlot();
builder()->DefineNamedOwnProperty(
builder()->Receiver(),
property->key()->AsLiteral()->AsRawPropertyName(),
feedback_index(slot));
} else {
DefineKeyedOwnPropertyFlags flags = DefineKeyedOwnPropertyFlag::kNoFlags;
if (property->NeedsSetFunctionName()) {
// Static class fields require the name property to be set on
// the class, meaning we can't wait until the
// DefineKeyedOwnProperty call later to set the name.
if (property->value()->IsClassLiteral() &&
property->value()->AsClassLiteral()->static_initializer() !=
nullptr) {
VisitClassLiteral(property->value()->AsClassLiteral(), key);
} else {
VisitForAccumulatorValue(property->value());
flags |= DefineKeyedOwnPropertyFlag::kSetFunctionName;
}
} else {
VisitForAccumulatorValue(property->value());
}
FeedbackSlot slot = feedback_spec()->AddDefineKeyedOwnICSlot();
builder()->DefineKeyedOwnProperty(builder()->Receiver(), key, flags,
feedback_index(slot));
}
}
void BytecodeGenerator::VisitInitializeClassMembersStatement(
InitializeClassMembersStatement* stmt) {
for (int i = 0; i < stmt->fields()->length(); i++) {
BuildClassProperty(stmt->fields()->at(i));
}
}
void BytecodeGenerator::VisitInitializeClassStaticElementsStatement(
InitializeClassStaticElementsStatement* stmt) {
for (int i = 0; i < stmt->elements()->length(); i++) {
ClassLiteral::StaticElement* element = stmt->elements()->at(i);
switch (element->kind()) {
case ClassLiteral::StaticElement::PROPERTY:
BuildClassProperty(element->property());
break;
case ClassLiteral::StaticElement::STATIC_BLOCK:
VisitBlock(element->static_block());
break;
}
}
}
void BytecodeGenerator::VisitAutoAccessorGetterBody(
AutoAccessorGetterBody* stmt) {
BuildVariableLoad(stmt->name_proxy()->var(), HoleCheckMode::kElided);
builder()->LoadKeyedProperty(
builder()->Receiver(),
feedback_index(feedback_spec()->AddKeyedLoadICSlot()));
BuildReturn(stmt->position());
}
void BytecodeGenerator::VisitAutoAccessorSetterBody(
AutoAccessorSetterBody* stmt) {
Register key = register_allocator()->NewRegister();
Register value = builder()->Parameter(0);
FeedbackSlot slot = feedback_spec()->AddKeyedStoreICSlot(language_mode());
BuildVariableLoad(stmt->name_proxy()->var(), HoleCheckMode::kElided);
builder()
->StoreAccumulatorInRegister(key)
.LoadAccumulatorWithRegister(value)
.SetKeyedProperty(builder()->Receiver(), key, feedback_index(slot),
language_mode());
}
void BytecodeGenerator::BuildInvalidPropertyAccess(MessageTemplate tmpl,
Property* property) {
RegisterAllocationScope register_scope(this);
const AstRawString* name = property->key()->AsVariableProxy()->raw_name();
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->LoadLiteral(Smi::FromEnum(tmpl))
.StoreAccumulatorInRegister(args[0])
.LoadLiteral(name)
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kNewTypeError, args)
.Throw();
}
void BytecodeGenerator::BuildPrivateBrandInitialization(Register receiver,
Variable* brand) {
BuildVariableLoad(brand, HoleCheckMode::kElided);
int depth = execution_context()->ContextChainDepth(brand->scope());
ContextScope* class_context = execution_context()->Previous(depth);
if (class_context) {
Register brand_reg = register_allocator()->NewRegister();
FeedbackSlot slot = feedback_spec()->AddDefineKeyedOwnICSlot();
builder()
->StoreAccumulatorInRegister(brand_reg)
.LoadAccumulatorWithRegister(class_context->reg())
.DefineKeyedOwnProperty(receiver, brand_reg,
DefineKeyedOwnPropertyFlag::kNoFlags,
feedback_index(slot));
} else {
// We are in the slow case where super() is called from a nested
// arrow function or an eval(), so the class scope context isn't
// tracked in a context register in the stack, and we have to
// walk the context chain from the runtime to find it.
DCHECK_NE(info()->literal()->scope()->outer_scope(), brand->scope());
RegisterList brand_args = register_allocator()->NewRegisterList(4);
builder()
->StoreAccumulatorInRegister(brand_args[1])
.MoveRegister(receiver, brand_args[0])
.MoveRegister(execution_context()->reg(), brand_args[2])
.LoadLiteral(Smi::FromInt(depth))
.StoreAccumulatorInRegister(brand_args[3])
.CallRuntime(Runtime::kAddPrivateBrand, brand_args);
}
}
void BytecodeGenerator::BuildInstanceMemberInitialization(Register constructor,
Register instance) {
RegisterList args = register_allocator()->NewRegisterList(1);
Register initializer = register_allocator()->NewRegister();
FeedbackSlot slot = feedback_spec()->AddLoadICSlot();
BytecodeLabel done;
builder()
->LoadClassFieldsInitializer(constructor, feedback_index(slot))
// TODO(gsathya): This jump can be elided for the base
// constructor and derived constructor. This is only required
// when called from an arrow function.
.JumpIfUndefined(&done)
.StoreAccumulatorInRegister(initializer)
.MoveRegister(instance, args[0])
.CallProperty(initializer, args,
feedback_index(feedback_spec()->AddCallICSlot()))
.Bind(&done);
}
void BytecodeGenerator::VisitNativeFunctionLiteral(
NativeFunctionLiteral* expr) {
size_t entry = builder()->AllocateDeferredConstantPoolEntry();
// Native functions don't use argument adaption and so have the special
// kDontAdaptArgumentsSentinel as their parameter count.
int index = feedback_spec()->AddCreateClosureParameterCount(
kDontAdaptArgumentsSentinel);
uint8_t flags = CreateClosureFlags::Encode(false, false, false);
builder()->CreateClosure(entry, index, flags);
native_function_literals_.push_back(std::make_pair(expr, entry));
}
void BytecodeGenerator::VisitConditionalChain(ConditionalChain* expr) {
ConditionalChainControlFlowBuilder conditional_builder(
builder(), block_coverage_builder_, expr,
expr->conditional_chain_length());
HoleCheckElisionMergeScope merge_elider(this);
{
bool should_visit_else_expression = true;
HoleCheckElisionScope elider(this);
for (size_t i = 0; i < expr->conditional_chain_length(); ++i) {
if (expr->condition_at(i)->ToBooleanIsTrue()) {
// Generate then block unconditionally as always true.
should_visit_else_expression = false;
HoleCheckElisionMergeScope::Branch branch(merge_elider);
conditional_builder.ThenAt(i);
VisitForAccumulatorValue(expr->then_expression_at(i));
break;
} else if (expr->condition_at(i)->ToBooleanIsFalse()) {
// Generate else block unconditionally by skipping the then block.
HoleCheckElisionMergeScope::Branch branch(merge_elider);
conditional_builder.ElseAt(i);
} else {
VisitForTest(
expr->condition_at(i), conditional_builder.then_labels_at(i),
conditional_builder.else_labels_at(i), TestFallthrough::kThen);
{
HoleCheckElisionMergeScope::Branch branch(merge_elider);
conditional_builder.ThenAt(i);
VisitForAccumulatorValue(expr->then_expression_at(i));
}
conditional_builder.JumpToEnd();
{
HoleCheckElisionMergeScope::Branch branch(merge_elider);
conditional_builder.ElseAt(i);
}
}
}
if (should_visit_else_expression) {
VisitForAccumulatorValue(expr->else_expression());
}
}
merge_elider.Merge();
}
void BytecodeGenerator::VisitConditional(Conditional* expr) {
ConditionalControlFlowBuilder conditional_builder(
builder(), block_coverage_builder_, expr);
if (expr->condition()->ToBooleanIsTrue()) {
// Generate then block unconditionally as always true.
conditional_builder.Then();
VisitForAccumulatorValue(expr->then_expression());
} else if (expr->condition()->ToBooleanIsFalse()) {
// Generate else block unconditionally if it exists.
conditional_builder.Else();
VisitForAccumulatorValue(expr->else_expression());
} else {
VisitForTest(expr->condition(), conditional_builder.then_labels(),
conditional_builder.else_labels(), TestFallthrough::kThen);
HoleCheckElisionMergeScope merge_elider(this);
conditional_builder.Then();
{
HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
VisitForAccumulatorValue(expr->then_expression());
}
conditional_builder.JumpToEnd();
conditional_builder.Else();
{
HoleCheckElisionMergeScope::Branch branch_elider(merge_elider);
VisitForAccumulatorValue(expr->else_expression());
}
merge_elider.Merge();
}
}
void BytecodeGenerator::VisitLiteral(Literal* expr) {
if (execution_result()->IsEffect()) return;
switch (expr->type()) {
case Literal::kSmi:
builder()->LoadLiteral(expr->AsSmiLiteral());
break;
case Literal::kHeapNumber:
builder()->LoadLiteral(expr->AsNumber());
break;
case Literal::kUndefined:
builder()->LoadUndefined();
break;
case Literal::kBoolean:
builder()->LoadBoolean(expr->ToBooleanIsTrue());
execution_result()->SetResultIsBoolean();
break;
case Literal::kNull:
builder()->LoadNull();
break;
case Literal::kTheHole:
builder()->LoadTheHole();
break;
case Literal::kString:
builder()->LoadLiteral(expr->AsRawString());
execution_result()->SetResultIsInternalizedString();
break;
case Literal::kConsString:
builder()->LoadLiteral(expr->AsConsString());
break;
case Literal::kBigInt:
builder()->LoadLiteral(expr->AsBigInt());
break;
}
}
void BytecodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
// Materialize a regular expression literal.
builder()->CreateRegExpLiteral(
expr->raw_pattern(), feedback_index(feedback_spec()->AddLiteralSlot()),
expr->flags());
}
void BytecodeGenerator::BuildCreateObjectLiteral(Register literal,
uint8_t flags, size_t entry) {
// TODO(cbruni): Directly generate runtime call for literals we cannot
// optimize once the CreateShallowObjectLiteral stub is in sync with the TF
// optimizations.
int literal_index = feedback_index(feedback_spec()->AddLiteralSlot());
builder()
->CreateObjectLiteral(entry, literal_index, flags)
.StoreAccumulatorInRegister(literal);
}
void BytecodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
expr->builder()->InitDepthAndFlags();
// Fast path for the empty object literal which doesn't need an
// AllocationSite.
if (expr->builder()->IsEmptyObjectLiteral()) {
DCHECK(expr->builder()->IsFastCloningSupported());
builder()->CreateEmptyObjectLiteral();
return;
}
Variable* home_object = expr->home_object();
if (home_object != nullptr) {
DCHECK(home_object->is_used());
DCHECK(home_object->IsContextSlot());
}
MultipleEntryBlockContextScope object_literal_context_scope(
this, home_object ? home_object->scope() : nullptr);
// Deep-copy the literal boilerplate.
uint8_t flags = CreateObjectLiteralFlags::Encode(
expr->builder()->ComputeFlags(),
expr->builder()->IsFastCloningSupported());
Register literal = register_allocator()->NewRegister();
// Create literal object.
int property_index = 0;
bool clone_object_spread =
expr->properties()->first()->kind() == ObjectLiteral::Property::SPREAD;
if (clone_object_spread) {
// Avoid the slow path for spreads in the following common cases:
// 1) `let obj = { ...source }`
// 2) `let obj = { ...source, override: 1 }`
// 3) `let obj = { ...source, ...overrides }`
RegisterAllocationScope register_scope(this);
Expression* property = expr->properties()->first()->value();
Register from_value = VisitForRegisterValue(property);
int clone_index = feedback_index(feedback_spec()->AddCloneObjectSlot());
builder()->CloneObject(from_value, flags, clone_index);
builder()->StoreAccumulatorInRegister(literal);
property_index++;
} else {
size_t entry;
// If constant properties is an empty fixed array, use a cached empty fixed
// array to ensure it's only added to the constant pool once.
if (expr->builder()->properties_count() == 0) {
entry = builder()->EmptyObjectBoilerplateDescriptionConstantPoolEntry();
} else {
entry = builder()->AllocateDeferredConstantPoolEntry();
object_literals_.push_back(std::make_pair(expr->builder(), entry));
}
BuildCreateObjectLiteral(literal, flags, entry);
}
// Store computed values into the literal.
AccessorTable<ObjectLiteral::Property> accessor_table(zone());
for (; property_index < expr->properties()->length(); property_index++) {
ObjectLiteral::Property* property = expr->properties()->at(property_index);
if (property->is_computed_name()) break;
if (!clone_object_spread && property->IsCompileTimeValue()) continue;
RegisterAllocationScope inner_register_scope(this);
Literal* key = property->key()->AsLiteral();
switch (property->kind()) {
case ObjectLiteral::Property::SPREAD:
UNREACHABLE();
case ObjectLiteral::Property::CONSTANT:
case ObjectLiteral::Property::MATERIALIZED_LITERAL:
DCHECK(clone_object_spread || !property->value()->IsCompileTimeValue());
[[fallthrough]];
case ObjectLiteral::Property::COMPUTED: {
// It is safe to use [[Put]] here because the boilerplate already
// contains computed properties with an uninitialized value.
Register key_reg;
if (key->IsStringLiteral()) {
DCHECK(key->IsPropertyName());
} else {
key_reg = register_allocator()->NewRegister();
builder()->SetExpressionPosition(property->key());
VisitForRegisterValue(property->key(), key_reg);
}
object_literal_context_scope.SetEnteredIf(
property->value()->IsConciseMethodDefinition());
builder()->SetExpressionPosition(property->value());
if (property->emit_store()) {
VisitForAccumulatorValue(property->value());
if (key->IsStringLiteral()) {
FeedbackSlot slot = feedback_spec()->AddDefineNamedOwnICSlot();
builder()->DefineNamedOwnProperty(literal, key->AsRawPropertyName(),
feedback_index(slot));
} else {
FeedbackSlot slot = feedback_spec()->AddDefineKeyedOwnICSlot();
builder()->DefineKeyedOwnProperty(
literal, key_reg, DefineKeyedOwnPropertyFlag::kNoFlags,
feedback_index(slot));
}
} else {
VisitForEffect(property->value());
}
break;
}
case ObjectLiteral::Property::PROTOTYPE: {
// __proto__:null is handled by CreateObjectLiteral.
if (property->IsNullPrototype()) break;
DCHECK(property->emit_store());
DCHECK(!property->NeedsSetFunctionName());
RegisterList args = register_allocator()->NewRegisterList(2);
builder()->MoveRegister(literal, args[0]);
object_literal_context_scope.SetEnteredIf(false);
builder()->SetExpressionPosition(property->value());
VisitForRegisterValue(property->value(), args[1]);
builder()->CallRuntime(Runtime::kInternalSetPrototype, args);
break;
}
case ObjectLiteral::Property::GETTER:
if (property->emit_store()) {
accessor_table.LookupOrInsert(key)->getter = property;
}
break;
case ObjectLiteral::Property::SETTER:
if (property->emit_store()) {
accessor_table.LookupOrInsert(key)->setter = property;
}
break;
}
}
// Define accessors, using only a single call to the runtime for each pair
// of corresponding getters and setters.
object_literal_context_scope.SetEnteredIf(true);
for (auto accessors : accessor_table.ordered_accessors()) {
RegisterAllocationScope inner_register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(5);
builder()->MoveRegister(literal, args[0]);
VisitForRegisterValue(accessors.first, args[1]);
VisitLiteralAccessor(accessors.second->getter, args[2]);
VisitLiteralAccessor(accessors.second->setter, args[3]);
builder()
->LoadLiteral(Smi::FromInt(NONE))
.StoreAccumulatorInRegister(args[4])
.CallRuntime(Runtime::kDefineAccessorPropertyUnchecked, args);
}
// Object literals have two parts. The "static" part on the left contains no
// computed property names, and so we can compute its map ahead of time; see
// Runtime_CreateObjectLiteralBoilerplate. The second "dynamic" part starts
// with the first computed property name and continues with all properties to
// its right. All the code from above initializes the static component of the
// object literal, and arranges for the map of the result to reflect the
// static order in which the keys appear. For the dynamic properties, we
// compile them into a series of "SetOwnProperty" runtime calls. This will
// preserve insertion order.
for (; property_index < expr->properties()->length(); property_index++) {
ObjectLiteral::Property* property = expr->properties()->at(property_index);
RegisterAllocationScope inner_register_scope(this);
bool should_be_in_object_literal_scope =
(property->value()->IsConciseMethodDefinition() ||
property->value()->IsAccessorFunctionDefinition());
if (property->IsPrototype()) {
// __proto__:null is handled by CreateObjectLiteral.
if (property->IsNullPrototype()) continue;
DCHECK(property->emit_store());
DCHECK(!property->NeedsSetFunctionName());
RegisterList args = register_allocator()->NewRegisterList(2);
builder()->MoveRegister(literal, args[0]);
DCHECK(!should_be_in_object_literal_scope);
object_literal_context_scope.SetEnteredIf(false);
builder()->SetExpressionPosition(property->value());
VisitForRegisterValue(property->value(), args[1]);
builder()->CallRuntime(Runtime::kInternalSetPrototype, args);
continue;
}
switch (property->kind()) {
case ObjectLiteral::Property::CONSTANT:
case ObjectLiteral::Property::COMPUTED:
case ObjectLiteral::Property::MATERIALIZED_LITERAL: {
// Computed property keys don't belong to the object literal scope (even
// if they're syntactically inside it).
if (property->is_computed_name()) {
object_literal_context_scope.SetEnteredIf(false);
}
Register key = register_allocator()->NewRegister();
BuildLoadPropertyKey(property, key);
object_literal_context_scope.SetEnteredIf(
should_be_in_object_literal_scope);
builder()->SetExpressionPosition(property->value());
DefineKeyedOwnPropertyInLiteralFlags data_property_flags =
DefineKeyedOwnPropertyInLiteralFlag::kNoFlags;
if (property->NeedsSetFunctionName()) {
// Static class fields require the name property to be set on
// the class, meaning we can't wait until the
// DefineKeyedOwnPropertyInLiteral call later to set the name.
if (property->value()->IsClassLiteral() &&
property->value()->AsClassLiteral()->static_initializer() !=
nullptr) {
VisitClassLiteral(property->value()->AsClassLiteral(), key);
} else {
data_property_flags |=
DefineKeyedOwnPropertyInLiteralFlag::kSetFunctionName;
VisitForAccumulatorValue(property->value());
}
} else {
VisitForAccumulatorValue(property->value());
}
FeedbackSlot slot =
feedback_spec()->AddDefineKeyedOwnPropertyInLiteralICSlot();
builder()->DefineKeyedOwnPropertyInLiteral(
literal, key, data_property_flags, feedback_index(slot));
break;
}
case ObjectLiteral::Property::GETTER:
case ObjectLiteral::Property::SETTER: {
// Computed property keys don't belong to the object literal scope (even
// if they're syntactically inside it).
if (property->is_computed_name()) {
object_literal_context_scope.SetEnteredIf(false);
}
RegisterList args = register_allocator()->NewRegisterList(4);
builder()->MoveRegister(literal, args[0]);
BuildLoadPropertyKey(property, args[1]);
DCHECK(should_be_in_object_literal_scope);
object_literal_context_scope.SetEnteredIf(true);
builder()->SetExpressionPosition(property->value());
VisitForRegisterValue(property->value(), args[2]);
builder()
->LoadLiteral(Smi::FromInt(NONE))
.StoreAccumulatorInRegister(args[3]);
Runtime::FunctionId function_id =
property->kind() == ObjectLiteral::Property::GETTER
? Runtime::kDefineGetterPropertyUnchecked
: Runtime::kDefineSetterPropertyUnchecked;
builder()->CallRuntime(function_id, args);
break;
}
case ObjectLiteral::Property::SPREAD: {
// TODO(olivf, chrome:1204540) This can be slower than the Babel
// translation. Should we compile this to a copying loop in bytecode?
RegisterList args = register_allocator()->NewRegisterList(2);
builder()->MoveRegister(literal, args[0]);
builder()->SetExpressionPosition(property->value());
object_literal_context_scope.SetEnteredIf(false);
VisitForRegisterValue(property->value(), args[1]);
builder()->CallRuntime(Runtime::kInlineCopyDataProperties, args);
break;
}
case ObjectLiteral::Property::PROTOTYPE:
UNREACHABLE(); // Handled specially above.
}
}
if (home_object != nullptr) {
object_literal_context_scope.SetEnteredIf(true);
builder()->LoadAccumulatorWithRegister(literal);
BuildVariableAssignment(home_object, Token::kInit, HoleCheckMode::kElided);
}
// Make sure to exit the scope before materialising the value into the
// accumulator, to prevent the context scope from clobbering it.
object_literal_context_scope.SetEnteredIf(false);
builder()->LoadAccumulatorWithRegister(literal);
}
// Fill an array with values from an iterator, starting at a given index. It is
// guaranteed that the loop will only terminate if the iterator is exhausted, or
// if one of iterator.next(), value.done, or value.value fail.
//
// In pseudocode:
//
// loop {
// value = iterator.next()
// if (value.done) break;
// value = value.value
// array[index++] = value
// }
void BytecodeGenerator::BuildFillArrayWithIterator(
IteratorRecord iterator, Register array, Register index, Register value,
FeedbackSlot next_value_slot, FeedbackSlot next_done_slot,
FeedbackSlot index_slot, FeedbackSlot element_slot) {
DCHECK(array.is_valid());
DCHECK(index.is_valid());
DCHECK(value.is_valid());
LoopBuilder loop_builder(builder(), nullptr, nullptr, feedback_spec());
LoopScope loop_scope(this, &loop_builder);
// Call the iterator's .next() method. Break from the loop if the `done`
// property is truthy, otherwise load the value from the iterator result and
// append the argument.
BuildIteratorNext(iterator, value);
builder()->LoadNamedProperty(
value, ast_string_constants()->done_string(),
feedback_index(feedback_spec()->AddLoadICSlot()));
loop_builder.BreakIfTrue(ToBooleanMode::kConvertToBoolean);
loop_builder.LoopBody();
builder()
// value = value.value
->LoadNamedProperty(value, ast_string_constants()->value_string(),
feedback_index(next_value_slot))
// array[index] = value
.StoreInArrayLiteral(array, index, feedback_index(element_slot))
// index++
.LoadAccumulatorWithRegister(index)
.UnaryOperation(Token::kInc, feedback_index(index_slot))
.StoreAccumulatorInRegister(index);
loop_builder.BindContinueTarget();
}
void BytecodeGenerator::BuildCreateArrayLiteral(
const ZonePtrList<Expression>* elements, ArrayLiteral* expr) {
RegisterAllocationScope register_scope(this);
// Make this the first register allocated so that it has a chance of aliasing
// the next register allocated after returning from this function.
Register array = register_allocator()->NewRegister();
Register index = register_allocator()->NewRegister();
SharedFeedbackSlot element_slot(feedback_spec(),
FeedbackSlotKind::kStoreInArrayLiteral);
ZonePtrList<Expression>::const_iterator current = elements->begin();
ZonePtrList<Expression>::const_iterator end = elements->end();
bool is_empty = elements->is_empty();
if (!is_empty && (*current)->IsSpread()) {
// If we have a leading spread, use CreateArrayFromIterable to create
// an array from it and then add the remaining components to that array.
VisitForAccumulatorValue(*current);
builder()->SetExpressionPosition((*current)->AsSpread()->expression());
builder()->CreateArrayFromIterable().StoreAccumulatorInRegister(array);
if (++current != end) {
// If there are remaining elements, prepare the index register that is
// used for adding those elements. The next index is the length of the
// newly created array.
auto length = ast_string_constants()->length_string();
int length_load_slot = feedback_index(feedback_spec()->AddLoadICSlot());
builder()
->LoadNamedProperty(array, length, length_load_slot)
.StoreAccumulatorInRegister(index);
}
} else {
// There are some elements before the first (if any) spread, and we can
// use a boilerplate when creating the initial array from those elements.
// First, allocate a constant pool entry for the boilerplate that will
// be created during finalization, and will contain all the constant
// elements before the first spread. This also handle the empty array case
// and one-shot optimization.
ArrayLiteralBoilerplateBuilder* array_literal_builder = nullptr;
if (expr != nullptr) {
array_literal_builder = expr->builder();
} else {
DCHECK(!elements->is_empty());
// get first_spread_index
int first_spread_index = -1;
for (auto iter = elements->begin(); iter != elements->end(); iter++) {
if ((*iter)->IsSpread()) {
first_spread_index = static_cast<int>(iter - elements->begin());
break;
}
}
array_literal_builder = zone()->New<ArrayLiteralBoilerplateBuilder>(
elements, first_spread_index);
array_literal_builder->InitDepthAndFlags();
}
DCHECK(array_literal_builder != nullptr);
uint8_t flags = CreateArrayLiteralFlags::Encode(
array_literal_builder->IsFastCloningSupported(),
array_literal_builder->ComputeFlags());
if (is_empty) {
// Empty array literal fast-path.
int literal_index = feedback_index(feedback_spec()->AddLiteralSlot());
DCHECK(array_literal_builder->IsFastCloningSupported());
builder()->CreateEmptyArrayLiteral(literal_index);
} else {
// Create array literal from boilerplate.
size_t entry = builder()->AllocateDeferredConstantPoolEntry();
array_literals_.push_back(std::make_pair(array_literal_builder, entry));
int literal_index = feedback_index(feedback_spec()->AddLiteralSlot());
builder()->CreateArrayLiteral(entry, literal_index, flags);
}
builder()->StoreAccumulatorInRegister(array);
ZonePtrList<Expression>::const_iterator first_spread_or_end =
array_literal_builder->first_spread_index() >= 0
? current + array_literal_builder->first_spread_index()
: end;
// Insert the missing non-constant elements, up until the first spread
// index, into the initial array (the remaining elements will be inserted
// below).
DCHECK_EQ(current, elements->begin());
int array_index = 0;
for (; current != first_spread_or_end; ++current, array_index++) {
Expression* subexpr = *current;
DCHECK(!subexpr->IsSpread());
// Skip the constants.
if (subexpr->IsCompileTimeValue()) continue;
builder()
->LoadLiteral(Smi::FromInt(array_index))
.StoreAccumulatorInRegister(index);
VisitForAccumulatorValue(subexpr);
builder()->StoreInArrayLiteral(array, index,
feedback_index(element_slot.Get()));
}
if (current != end) {
// If there are remaining elements, prepare the index register
// to store the next element, which comes from the first spread.
builder()
->LoadLiteral(Smi::FromInt(array_index))
.StoreAccumulatorInRegister(index);
}
}
// Now build insertions for the remaining elements from current to end.
SharedFeedbackSlot index_slot(feedback_spec(), FeedbackSlotKind::kBinaryOp);
SharedFeedbackSlot length_slot(
feedback_spec(), feedback_spec()->GetStoreICSlot(LanguageMode::kStrict));
for (; current != end; ++current) {
Expression* subexpr = *current;
if (subexpr->IsSpread()) {
RegisterAllocationScope scope(this);
builder()->SetExpressionPosition(subexpr->AsSpread()->expression());
VisitForAccumulatorValue(subexpr->AsSpread()->expression());
builder()->SetExpressionPosition(subexpr->AsSpread()->expression());
IteratorRecord iterator = BuildGetIteratorRecord(IteratorType::kNormal);
Register value = register_allocator()->NewRegister();
FeedbackSlot next_value_load_slot = feedback_spec()->AddLoadICSlot();
FeedbackSlot next_done_load_slot = feedback_spec()->AddLoadICSlot();
FeedbackSlot real_index_slot = index_slot.Get();
FeedbackSlot real_element_slot = element_slot.Get();
BuildFillArrayWithIterator(iterator, array, index, value,
next_value_load_slot, next_done_load_slot,
real_index_slot, real_element_slot);
} else if (!subexpr->IsTheHoleLiteral()) {
// literal[index++] = subexpr
VisitForAccumulatorValue(subexpr);
builder()
->StoreInArrayLiteral(array, index,
feedback_index(element_slot.Get()))
.LoadAccumulatorWithRegister(index);
// Only increase the index if we are not the last element.
if (current + 1 != end) {
builder()
->UnaryOperation(Token::kInc, feedback_index(index_slot.Get()))
.StoreAccumulatorInRegister(index);
}
} else {
// literal.length = ++index
// length_slot is only used when there are holes.
auto length = ast_string_constants()->length_string();
builder()
->LoadAccumulatorWithRegister(index)
.UnaryOperation(Token::kInc, feedback_index(index_slot.Get()))
.StoreAccumulatorInRegister(index)
.SetNamedProperty(array, length, feedback_index(length_slot.Get()),
LanguageMode::kStrict);
}
}
builder()->LoadAccumulatorWithRegister(array);
}
void BytecodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
expr->builder()->InitDepthAndFlags();
BuildCreateArrayLiteral(expr->values(), expr);
}
void BytecodeGenerator::VisitVariableProxy(VariableProxy* proxy) {
builder()->SetExpressionPosition(proxy);
BuildVariableLoad(proxy->var(), proxy->hole_check_mode());
}
bool BytecodeGenerator::IsVariableInRegister(Variable* var, Register reg) {
BytecodeRegisterOptimizer* optimizer = builder()->GetRegisterOptimizer();
if (optimizer) {
return optimizer->IsVariableInRegister(var, reg);
}
return false;
}
void BytecodeGenerator::SetVariableInRegister(Variable* var, Register reg) {
BytecodeRegisterOptimizer* optimizer = builder()->GetRegisterOptimizer();
if (optimizer) {
optimizer->SetVariableInRegister(var, reg);
}
}
Variable* BytecodeGenerator::GetPotentialVariableInAccumulator() {
BytecodeRegisterOptimizer* optimizer = builder()->GetRegisterOptimizer();
if (optimizer) {
return optimizer->GetPotentialVariableInAccumulator();
}
return nullptr;
}
void BytecodeGenerator::BuildVariableLoad(Variable* variable,
HoleCheckMode hole_check_mode,
TypeofMode typeof_mode) {
switch (variable->location()) {
case VariableLocation::LOCAL: {
Register source(builder()->Local(variable->index()));
// We need to load the variable into the accumulator, even when in a
// VisitForRegisterScope, in order to avoid register aliasing if
// subsequent expressions assign to the same variable.
builder()->LoadAccumulatorWithRegister(source);
if (VariableNeedsHoleCheckInCurrentBlock(variable, hole_check_mode)) {
BuildThrowIfHole(variable);
}
break;
}
case VariableLocation::PARAMETER: {
Register source;
if (variable->IsReceiver()) {
source = builder()->Receiver();
} else {
source = builder()->Parameter(variable->index());
}
// We need to load the variable into the accumulator, even when in a
// VisitForRegisterScope, in order to avoid register aliasing if
// subsequent expressions assign to the same variable.
builder()->LoadAccumulatorWithRegister(source);
if (VariableNeedsHoleCheckInCurrentBlock(variable, hole_check_mode)) {
BuildThrowIfHole(variable);
}
break;
}
case VariableLocation::UNALLOCATED: {
// The global identifier "undefined" is immutable. Everything
// else could be reassigned. For performance, we do a pointer comparison
// rather than checking if the raw_name is really "undefined".
if (variable->raw_name() == ast_string_constants()->undefined_string()) {
builder()->LoadUndefined();
} else {
FeedbackSlot slot = GetCachedLoadGlobalICSlot(typeof_mode, variable);
builder()->LoadGlobal(variable->raw_name(), feedback_index(slot),
typeof_mode);
}
break;
}
case VariableLocation::CONTEXT: {
int depth = execution_context()->ContextChainDepth(variable->scope());
ContextScope* context = execution_context()->Previous(depth);
Register context_reg;
if (context) {
context_reg = context->reg();
depth = 0;
} else {
context_reg = execution_context()->reg();
}
BytecodeArrayBuilder::ContextSlotMutability immutable =
(variable->maybe_assigned() == kNotAssigned)
? BytecodeArrayBuilder::kImmutableSlot
: BytecodeArrayBuilder::kMutableSlot;
Register acc = Register::virtual_accumulator();
if (immutable == BytecodeArrayBuilder::kImmutableSlot &&
IsVariableInRegister(variable, acc)) {
return;
}
builder()->LoadContextSlot(context_reg, variable, depth, immutable);
if (VariableNeedsHoleCheckInCurrentBlock(variable, hole_check_mode)) {
BuildThrowIfHole(variable);
}
if (immutable == BytecodeArrayBuilder::kImmutableSlot) {
SetVariableInRegister(variable, acc);
}
break;
}
case VariableLocation::LOOKUP: {
switch (variable->mode()) {
case VariableMode::kDynamicLocal: {
Variable* local_variable = variable->local_if_not_shadowed();
int depth =
execution_context()->ContextChainDepth(local_variable->scope());
ContextMode context_mode =
(local_variable->scope()->has_context_cells()
? ContextMode::kHasContextCells
: ContextMode::kNoContextCells);
builder()->LoadLookupContextSlot(variable->raw_name(), typeof_mode,
context_mode,
local_variable->index(), depth);
if (VariableNeedsHoleCheckInCurrentBlock(local_variable,
hole_check_mode)) {
BuildThrowIfHole(local_variable);
}
break;
}
case VariableMode::kDynamicGlobal: {
int depth =
current_scope()->ContextChainLengthUntilOutermostSloppyEval();
// TODO(1008414): Add back caching here when bug is fixed properly.
FeedbackSlot slot = feedback_spec()->AddLoadGlobalICSlot(typeof_mode);
builder()->LoadLookupGlobalSlot(variable->raw_name(), typeof_mode,
feedback_index(slot), depth);
break;
}
default: {
// Normally, private names should not be looked up dynamically,
// but we make an exception in debug-evaluate, in that case the
// lookup will be done in %SetPrivateMember() and %GetPrivateMember()
// calls, not here.
DCHECK(!variable->raw_name()->IsPrivateName());
builder()->LoadLookupSlot(variable->raw_name(), typeof_mode);
break;
}
}
break;
}
case VariableLocation::MODULE: {
int depth = execution_context()->ContextChainDepth(variable->scope());
builder()->LoadModuleVariable(variable->index(), depth);
if (VariableNeedsHoleCheckInCurrentBlock(variable, hole_check_mode)) {
BuildThrowIfHole(variable);
}
break;
}
case VariableLocation::REPL_GLOBAL: {
DCHECK(variable->IsReplGlobal());
FeedbackSlot slot = GetCachedLoadGlobalICSlot(typeof_mode, variable);
builder()->LoadGlobal(variable->raw_name(), feedback_index(slot),
typeof_mode);
break;
}
}
}
void BytecodeGenerator::BuildVariableLoadForAccumulatorValue(
Variable* variable, HoleCheckMode hole_check_mode, TypeofMode typeof_mode) {
ValueResultScope accumulator_result(this);
BuildVariableLoad(variable, hole_check_mode, typeof_mode);
}
void BytecodeGenerator::BuildReturn(int source_position) {
if (v8_flags.trace) {
RegisterAllocationScope register_scope(this);
Register result = register_allocator()->NewRegister();
// Runtime returns {result} value, preserving accumulator.
builder()->StoreAccumulatorInRegister(result).CallRuntime(
Runtime::kTraceExit, result);
}
builder()->SetStatementPosition(source_position);
builder()->Return();
}
void BytecodeGenerator::BuildAsyncReturn(int source_position) {
RegisterAllocationScope register_scope(this);
if (IsAsyncGeneratorFunction(info()->literal()->kind())) {
RegisterList args = register_allocator()->NewRegisterList(3);
builder()
->MoveRegister(generator_object(), args[0]) // generator
.StoreAccumulatorInRegister(args[1]) // value
.LoadTrue()
.StoreAccumulatorInRegister(args[2]) // done
.CallRuntime(Runtime::kInlineAsyncGeneratorResolve, args);
} else {
DCHECK(IsAsyncFunction(info()->literal()->kind()) ||
IsModuleWithTopLevelAwait(info()->literal()->kind()));
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(generator_object(), args[0]) // generator
.StoreAccumulatorInRegister(args[1]) // value
.CallRuntime(Runtime::kInlineAsyncFunctionResolve, args);
}
BuildReturn(source_position);
}
void BytecodeGenerator::BuildReThrow() { builder()->ReThrow(); }
void BytecodeGenerator::RememberHoleCheckInCurrentBlock(Variable* variable) {
if (!v8_flags.ignition_elide_redundant_tdz_checks) return;
// The first N-1 variables that need hole checks may be cached in a bitmap to
// elide subsequent hole checks in the same basic block, where N is
// Variable::kHoleCheckBitmapBits.
//
// This numbering is done during bytecode generation instead of scope analysis
// for 2 reasons:
//
// 1. There may be multiple eagerly compiled inner functions during a single
// run of scope analysis, so a global numbering will result in fewer variables
// with cacheable hole checks.
//
// 2. Compiler::CollectSourcePositions reparses functions and checks that the
// recompiled bytecode is identical. Therefore the numbering must be kept
// identical regardless of whether a function is eagerly compiled as part of
// an outer compilation or recompiled during source position collection. The
// simplest way to guarantee identical numbering is to scope it to the
// compilation instead of scope analysis.
variable->RememberHoleCheckInBitmap(hole_check_bitmap_,
vars_in_hole_check_bitmap_);
}
void BytecodeGenerator::BuildThrowIfHole(Variable* variable) {
if (variable->is_this()) {
DCHECK(variable->mode() == VariableMode::kConst);
builder()->ThrowSuperNotCalledIfHole();
} else {
builder()->ThrowReferenceErrorIfHole(variable->raw_name());
}
RememberHoleCheckInCurrentBlock(variable);
}
bool BytecodeGenerator::VariableNeedsHoleCheckInCurrentBlock(
Variable* variable, HoleCheckMode hole_check_mode) {
return hole_check_mode == HoleCheckMode::kRequired &&
!variable->HasRememberedHoleCheck(hole_check_bitmap_);
}
bool BytecodeGenerator::VariableNeedsHoleCheckInCurrentBlockForAssignment(
Variable* variable, Token::Value op, HoleCheckMode hole_check_mode) {
return VariableNeedsHoleCheckInCurrentBlock(variable, hole_check_mode) ||
(variable->is_this() && variable->mode() == VariableMode::kConst &&
op == Token::kInit);
}
void BytecodeGenerator::BuildHoleCheckForVariableAssignment(Variable* variable,
Token::Value op) {
DCHECK(!IsPrivateMethodOrAccessorVariableMode(variable->mode()));
DCHECK(VariableNeedsHoleCheckInCurrentBlockForAssignment(
variable, op, HoleCheckMode::kRequired));
if (variable->is_this()) {
DCHECK(variable->mode() == VariableMode::kConst && op == Token::kInit);
// Perform an initialization check for 'this'. 'this' variable is the
// only variable able to trigger bind operations outside the TDZ
// via 'super' calls.
//
// Do not remember the hole check because this bytecode throws if 'this' is
// *not* the hole, i.e. the opposite of the TDZ hole check.
builder()->ThrowSuperAlreadyCalledIfNotHole();
} else {
// Perform an initialization check for let/const declared variables.
// E.g. let x = (x = 20); is not allowed.
DCHECK(IsLexicalVariableMode(variable->mode()));
BuildThrowIfHole(variable);
}
}
void BytecodeGenerator::AddDisposableValue(VariableMode mode) {
if (mode == VariableMode::kUsing) {
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(current_disposables_stack(), args[0])
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kAddDisposableValue, args);
} else if (mode == VariableMode::kAwaitUsing) {
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(current_disposables_stack(), args[0])
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kAddAsyncDisposableValue, args);
}
}
void BytecodeGenerator::BuildVariableAssignment(
Variable* variable, Token::Value op, HoleCheckMode hole_check_mode,
LookupHoistingMode lookup_hoisting_mode) {
VariableMode mode = variable->mode();
RegisterAllocationScope assignment_register_scope(this);
switch (variable->location()) {
case VariableLocation::PARAMETER:
case VariableLocation::LOCAL: {
Register destination;
if (VariableLocation::PARAMETER == variable->location()) {
if (variable->IsReceiver()) {
destination = builder()->Receiver();
} else {
destination = builder()->Parameter(variable->index());
}
} else {
destination = builder()->Local(variable->index());
}
if (VariableNeedsHoleCheckInCurrentBlockForAssignment(variable, op,
hole_check_mode)) {
// Load destination to check for hole.
Register value_temp = register_allocator()->NewRegister();
builder()
->StoreAccumulatorInRegister(value_temp)
.LoadAccumulatorWithRegister(destination);
BuildHoleCheckForVariableAssignment(variable, op);
builder()->LoadAccumulatorWithRegister(value_temp);
}
if ((mode != VariableMode::kConst && mode != VariableMode::kUsing &&
mode != VariableMode::kAwaitUsing) ||
op == Token::kInit) {
if (op == Token::kInit) {
if (variable->HasHoleCheckUseInSameClosureScope()) {
// After initializing a variable it won't be the hole anymore, so
// elide subsequent checks.
RememberHoleCheckInCurrentBlock(variable);
}
AddDisposableValue(mode);
}
builder()->StoreAccumulatorInRegister(destination);
} else if (variable->throw_on_const_assignment(language_mode()) &&
mode == VariableMode::kConst) {
builder()->CallRuntime(Runtime::kThrowConstAssignError);
} else if (variable->throw_on_const_assignment(language_mode()) &&
mode == VariableMode::kUsing) {
builder()->CallRuntime(Runtime::kThrowUsingAssignError);
}
break;
}
case VariableLocation::UNALLOCATED: {
BuildStoreGlobal(variable);
break;
}
case VariableLocation::CONTEXT: {
int depth = execution_context()->ContextChainDepth(variable->scope());
ContextScope* context = execution_context()->Previous(depth);
Register context_reg;
if (context) {
context_reg = context->reg();
depth = 0;
} else {
context_reg = execution_context()->reg();
}
if (VariableNeedsHoleCheckInCurrentBlockForAssignment(variable, op,
hole_check_mode)) {
// Load destination to check for hole.
Register value_temp = register_allocator()->NewRegister();
builder()
->StoreAccumulatorInRegister(value_temp)
.LoadContextSlot(context_reg, variable, depth,
BytecodeArrayBuilder::kMutableSlot);
BuildHoleCheckForVariableAssignment(variable, op);
builder()->LoadAccumulatorWithRegister(value_temp);
}
if ((mode != VariableMode::kConst && mode != VariableMode::kUsing &&
mode != VariableMode::kAwaitUsing) ||
op == Token::kInit) {
if (op == Token::kInit) {
if (variable->HasHoleCheckUseInSameClosureScope()) {
// After initializing a variable it won't be the hole anymore, so
// elide subsequent checks.
RememberHoleCheckInCurrentBlock(variable);
}
AddDisposableValue(mode);
}
builder()->StoreContextSlot(context_reg, variable, depth);
} else if (variable->throw_on_const_assignment(language_mode())) {
builder()->CallRuntime(Runtime::kThrowConstAssignError);
}
break;
}
case VariableLocation::LOOKUP: {
builder()->StoreLookupSlot(variable->raw_name(), language_mode(),
lookup_hoisting_mode);
break;
}
case VariableLocation::MODULE: {
DCHECK(IsDeclaredVariableMode(mode));
if (mode == VariableMode::kConst && op != Token::kInit) {
builder()->CallRuntime(Runtime::kThrowConstAssignError);
break;
}
// If we don't throw above, we know that we're dealing with an
// export because imports are const and we do not generate initializing
// assignments for them.
DCHECK(variable->IsExport());
int depth = execution_context()->ContextChainDepth(variable->scope());
if (VariableNeedsHoleCheckInCurrentBlockForAssignment(variable, op,
hole_check_mode)) {
Register value_temp = register_allocator()->NewRegister();
builder()
->StoreAccumulatorInRegister(value_temp)
.LoadModuleVariable(variable->index(), depth);
BuildHoleCheckForVariableAssignment(variable, op);
builder()->LoadAccumulatorWithRegister(value_temp);
}
builder()->StoreModuleVariable(variable->index(), depth);
break;
}
case VariableLocation::REPL_GLOBAL: {
// A let or const declaration like 'let x = 7' is effectively translated
// to:
// <top of the script>:
// ScriptContext.x = TheHole;
// ...
// <where the actual 'let' is>:
// ScriptContextTable.x = 7; // no hole check
//
// The ScriptContext slot for 'x' that we store to here is not
// necessarily the ScriptContext of this script, but rather the
// first ScriptContext that has a slot for name 'x'.
DCHECK(variable->IsReplGlobal());
if (op == Token::kInit) {
RegisterList store_args = register_allocator()->NewRegisterList(2);
builder()
->StoreAccumulatorInRegister(store_args[1])
.LoadLiteral(variable->raw_name())
.StoreAccumulatorInRegister(store_args[0]);
builder()->CallRuntime(
Runtime::kStoreGlobalNoHoleCheckForReplLetOrConst, store_args);
} else {
if (mode == VariableMode::kConst) {
builder()->CallRuntime(Runtime::kThrowConstAssignError);
} else {
BuildStoreGlobal(variable);
}
}
break;
}
}
}
void BytecodeGenerator::BuildLoadNamedProperty(const Expression* object_expr,
Register object,
const AstRawString* name) {
FeedbackSlot slot = GetCachedLoadICSlot(object_expr, name);
builder()->LoadNamedProperty(object, name, feedback_index(slot));
}
void BytecodeGenerator::BuildSetNamedProperty(const Expression* object_expr,
Register object,
const AstRawString* name) {
Register value;
if (!execution_result()->IsEffect()) {
value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
}
FeedbackSlot slot = GetCachedStoreICSlot(object_expr, name);
builder()->SetNamedProperty(object, name, feedback_index(slot),
language_mode());
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
}
void BytecodeGenerator::BuildStoreGlobal(Variable* variable) {
Register value;
if (!execution_result()->IsEffect()) {
value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
}
FeedbackSlot slot = GetCachedStoreGlobalICSlot(language_mode(), variable);
builder()->StoreGlobal(variable->raw_name(), feedback_index(slot));
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
}
void BytecodeGenerator::BuildLoadKeyedProperty(Register object,
FeedbackSlot slot) {
if (v8_flags.enable_enumerated_keyed_access_bytecode &&
current_for_in_scope() != nullptr) {
Variable* key = GetPotentialVariableInAccumulator();
if (key != nullptr) {
ForInScope* scope = current_for_in_scope()->GetForInScope(key);
if (scope != nullptr) {
Register enum_index = scope->enum_index();
Register cache_type = scope->cache_type();
builder()->LoadEnumeratedKeyedProperty(object, enum_index, cache_type,
feedback_index(slot));
return;
}
}
}
builder()->LoadKeyedProperty(object, feedback_index(slot));
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::NonProperty(Expression* expr) {
return AssignmentLhsData(NON_PROPERTY, expr, RegisterList(), Register(),
Register(), nullptr, nullptr);
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::NamedProperty(Expression* object_expr,
Register object,
const AstRawString* name) {
return AssignmentLhsData(NAMED_PROPERTY, nullptr, RegisterList(), object,
Register(), object_expr, name);
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::KeyedProperty(Register object,
Register key) {
return AssignmentLhsData(KEYED_PROPERTY, nullptr, RegisterList(), object, key,
nullptr, nullptr);
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::NamedSuperProperty(
RegisterList super_property_args) {
return AssignmentLhsData(NAMED_SUPER_PROPERTY, nullptr, super_property_args,
Register(), Register(), nullptr, nullptr);
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::PrivateMethodOrAccessor(
AssignType type, Property* property, Register object, Register key) {
return AssignmentLhsData(type, property, RegisterList(), object, key, nullptr,
nullptr);
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::PrivateDebugEvaluate(AssignType type,
Property* property,
Register object) {
return AssignmentLhsData(type, property, RegisterList(), object, Register(),
nullptr, nullptr);
}
// static
BytecodeGenerator::AssignmentLhsData
BytecodeGenerator::AssignmentLhsData::KeyedSuperProperty(
RegisterList super_property_args) {
return AssignmentLhsData(KEYED_SUPER_PROPERTY, nullptr, super_property_args,
Register(), Register(), nullptr, nullptr);
}
BytecodeGenerator::AssignmentLhsData BytecodeGenerator::PrepareAssignmentLhs(
Expression* lhs, AccumulatorPreservingMode accumulator_preserving_mode) {
// Left-hand side can only be a property, a global or a variable slot.
Property* property = lhs->AsProperty();
AssignType assign_type = Property::GetAssignType(property);
// Evaluate LHS expression.
switch (assign_type) {
case NON_PROPERTY:
return AssignmentLhsData::NonProperty(lhs);
case NAMED_PROPERTY: {
AccumulatorPreservingScope scope(this, accumulator_preserving_mode);
Register object = VisitForRegisterValue(property->obj());
const AstRawString* name =
property->key()->AsLiteral()->AsRawPropertyName();
return AssignmentLhsData::NamedProperty(property->obj(), object, name);
}
case KEYED_PROPERTY: {
AccumulatorPreservingScope scope(this, accumulator_preserving_mode);
Register object = VisitForRegisterValue(property->obj());
Register key = VisitForRegisterValue(property->key());
return AssignmentLhsData::KeyedProperty(object, key);
}
case PRIVATE_METHOD:
case PRIVATE_GETTER_ONLY:
case PRIVATE_SETTER_ONLY:
case PRIVATE_GETTER_AND_SETTER: {
DCHECK(!property->IsSuperAccess());
AccumulatorPreservingScope scope(this, accumulator_preserving_mode);
Register object = VisitForRegisterValue(property->obj());
Register key = VisitForRegisterValue(property->key());
return AssignmentLhsData::PrivateMethodOrAccessor(assign_type, property,
object, key);
}
case PRIVATE_DEBUG_DYNAMIC: {
AccumulatorPreservingScope scope(this, accumulator_preserving_mode);
Register object = VisitForRegisterValue(property->obj());
// Do not visit the key here, instead we will look them up at run time.
return AssignmentLhsData::PrivateDebugEvaluate(assign_type, property,
object);
}
case NAMED_SUPER_PROPERTY: {
AccumulatorPreservingScope scope(this, accumulator_preserving_mode);
RegisterList super_property_args =
register_allocator()->NewRegisterList(4);
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(super_property_args[0]);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(super_property_args[1]);
builder()
->LoadLiteral(property->key()->AsLiteral()->AsRawPropertyName())
.StoreAccumulatorInRegister(super_property_args[2]);
return AssignmentLhsData::NamedSuperProperty(super_property_args);
}
case KEYED_SUPER_PROPERTY: {
AccumulatorPreservingScope scope(this, accumulator_preserving_mode);
RegisterList super_property_args =
register_allocator()->NewRegisterList(4);
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(super_property_args[0]);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(super_property_args[1]);
VisitForRegisterValue(property->key(), super_property_args[2]);
return AssignmentLhsData::KeyedSuperProperty(super_property_args);
}
}
UNREACHABLE();
}
// Build the iteration finalizer called in the finally block of an iteration
// protocol execution. This closes the iterator if needed, and suppresses any
// exception it throws if necessary, including the exception when the return
// method is not callable.
//
// In pseudo-code, this builds:
//
// if (!done) {
// try {
// let method = iterator.return
// if (method !== null && method !== undefined) {
// let return_val = method.call(iterator)
// if (!%IsObject(return_val)) throw TypeError
// }
// } catch (e) {
// if (iteration_continuation != RETHROW)
// rethrow e
// }
// }
//
// For async iterators, iterator.close() becomes await iterator.close().
void BytecodeGenerator::BuildFinalizeIteration(
IteratorRecord iterator, Register done,
Register iteration_continuation_token) {
RegisterAllocationScope register_scope(this);
BytecodeLabels iterator_is_done(zone());
// if (!done) {
builder()->LoadAccumulatorWithRegister(done).JumpIfTrue(
ToBooleanMode::kConvertToBoolean, iterator_is_done.New());
{
RegisterAllocationScope inner_register_scope(this);
BuildTryCatch(
// try {
// let method = iterator.return
// if (method !== null && method !== undefined) {
// let return_val = method.call(iterator)
// if (!%IsObject(return_val)) throw TypeError
// }
// }
[&]() {
Register method = register_allocator()->NewRegister();
builder()
->LoadNamedProperty(
iterator.object(), ast_string_constants()->return_string(),
feedback_index(feedback_spec()->AddLoadICSlot()))
.JumpIfUndefinedOrNull(iterator_is_done.New())
.StoreAccumulatorInRegister(method);
RegisterList args(iterator.object());
builder()->CallProperty(
method, args, feedback_index(feedback_spec()->AddCallICSlot()));
if (iterator.type() == IteratorType::kAsync) {
BuildAwait();
}
builder()->JumpIfJSReceiver(iterator_is_done.New());
{
// Throw this exception inside the try block so that it is
// suppressed by the iteration continuation if necessary.
RegisterAllocationScope register_scope(this);
Register return_result = register_allocator()->NewRegister();
builder()
->StoreAccumulatorInRegister(return_result)
.CallRuntime(Runtime::kThrowIteratorResultNotAnObject,
return_result);
}
},
// catch (e) {
// if (iteration_continuation != RETHROW)
// rethrow e
// }
[&](Register context) {
// Reuse context register to store the exception.
Register close_exception = context;
builder()->StoreAccumulatorInRegister(close_exception);
BytecodeLabel suppress_close_exception;
builder()
->LoadLiteral(Smi::FromInt(
static_cast<int>(TryFinallyContinuationToken::kRethrowToken)))
.CompareReference(iteration_continuation_token)
.JumpIfTrue(ToBooleanMode::kAlreadyBoolean,
&suppress_close_exception)
.LoadAccumulatorWithRegister(close_exception)
.ReThrow()
.Bind(&suppress_close_exception);
},
catch_prediction());
}
iterator_is_done.Bind(builder());
}
// Get the default value of a destructuring target. Will mutate the
// destructuring target expression if there is a default value.
//
// For
// a = b
// in
// let {a = b} = c
// returns b and mutates the input into a.
Expression* BytecodeGenerator::GetDestructuringDefaultValue(
Expression** target) {
Expression* default_value = nullptr;
if ((*target)->IsAssignment()) {
Assignment* default_init = (*target)->AsAssignment();
DCHECK_EQ(default_init->op(), Token::kAssign);
default_value = default_init->value();
*target = default_init->target();
DCHECK((*target)->IsValidReferenceExpression() || (*target)->IsPattern());
}
return default_value;
}
// Convert a destructuring assignment to an array literal into a sequence of
// iterator accesses into the value being assigned (in the accumulator).
//
// [a().x, ...b] = accumulator
//
// becomes
//
// iterator = %GetIterator(accumulator)
// try {
//
// // Individual assignments read off the value from iterator.next() This gets
// // repeated per destructuring element.
// if (!done) {
// // Make sure we are considered 'done' if .next(), .done or .value fail.
// done = true
// var next_result = iterator.next()
// var tmp_done = next_result.done
// if (!tmp_done) {
// value = next_result.value
// done = false
// }
// }
// if (done)
// value = undefined
// a().x = value
//
// // A spread receives the remaining items in the iterator.
// var array = []
// var index = 0
// %FillArrayWithIterator(iterator, array, index, done)
// done = true
// b = array
//
// } catch(e) {
// iteration_continuation = RETHROW
// } finally {
// %FinalizeIteration(iterator, done, iteration_continuation)
// }
void BytecodeGenerator::BuildDestructuringArrayAssignment(
ArrayLiteral* pattern, Token::Value op,
LookupHoistingMode lookup_hoisting_mode) {
RegisterAllocationScope scope(this);
Register value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
// Store the iterator in a dedicated register so that it can be closed on
// exit, and the 'done' value in a dedicated register so that it can be
// changed and accessed independently of the iteration result.
IteratorRecord iterator = BuildGetIteratorRecord(IteratorType::kNormal);
Register done = register_allocator()->NewRegister();
builder()->LoadFalse();
builder()->StoreAccumulatorInRegister(done);
BuildTryFinally(
// Try block.
[&]() {
Register next_result = register_allocator()->NewRegister();
FeedbackSlot next_value_load_slot = feedback_spec()->AddLoadICSlot();
FeedbackSlot next_done_load_slot = feedback_spec()->AddLoadICSlot();
Spread* spread = nullptr;
for (Expression* target : *pattern->values()) {
if (target->IsSpread()) {
spread = target->AsSpread();
break;
}
Expression* default_value = GetDestructuringDefaultValue(&target);
builder()->SetExpressionPosition(target);
AssignmentLhsData lhs_data = PrepareAssignmentLhs(target);
// if (!done) {
// // Make sure we are considered done if .next(), .done or .value
// // fail.
// done = true
// var next_result = iterator.next()
// var tmp_done = next_result.done
// if (!tmp_done) {
// value = next_result.value
// done = false
// }
// }
// if (done)
// value = undefined
BytecodeLabels is_done(zone());
builder()->LoadAccumulatorWithRegister(done);
builder()->JumpIfTrue(ToBooleanMode::kConvertToBoolean,
is_done.New());
builder()->LoadTrue().StoreAccumulatorInRegister(done);
BuildIteratorNext(iterator, next_result);
builder()
->LoadNamedProperty(next_result,
ast_string_constants()->done_string(),
feedback_index(next_done_load_slot))
.JumpIfTrue(ToBooleanMode::kConvertToBoolean, is_done.New());
// Only do the assignment if this is not a hole (i.e. 'elided').
if (!target->IsTheHoleLiteral()) {
builder()
->LoadNamedProperty(next_result,
ast_string_constants()->value_string(),
feedback_index(next_value_load_slot))
.StoreAccumulatorInRegister(next_result)
.LoadFalse()
.StoreAccumulatorInRegister(done)
.LoadAccumulatorWithRegister(next_result);
// [<pattern> = <init>] = <value>
// becomes (roughly)
// temp = <value>.next();
// <pattern> = temp === undefined ? <init> : temp;
BytecodeLabel do_assignment;
if (default_value) {
builder()->JumpIfNotUndefined(&do_assignment);
// Since done == true => temp == undefined, jump directly to using
// the default value for that case.
is_done.Bind(builder());
VisitInHoleCheckElisionScopeForAccumulatorValue(default_value);
} else {
builder()->Jump(&do_assignment);
is_done.Bind(builder());
builder()->LoadUndefined();
}
builder()->Bind(&do_assignment);
BuildAssignment(lhs_data, op, lookup_hoisting_mode);
} else {
builder()->LoadFalse().StoreAccumulatorInRegister(done);
DCHECK_EQ(lhs_data.assign_type(), NON_PROPERTY);
is_done.Bind(builder());
}
}
if (spread) {
RegisterAllocationScope scope(this);
BytecodeLabel is_done;
// A spread is turned into a loop over the remainer of the iterator.
Expression* target = spread->expression();
builder()->SetExpressionPosition(spread);
AssignmentLhsData lhs_data = PrepareAssignmentLhs(target);
// var array = [];
Register array = register_allocator()->NewRegister();
builder()->CreateEmptyArrayLiteral(
feedback_index(feedback_spec()->AddLiteralSlot()));
builder()->StoreAccumulatorInRegister(array);
// If done, jump to assigning empty array
builder()->LoadAccumulatorWithRegister(done);
builder()->JumpIfTrue(ToBooleanMode::kConvertToBoolean, &is_done);
// var index = 0;
Register index = register_allocator()->NewRegister();
builder()->LoadLiteral(Smi::zero());
builder()->StoreAccumulatorInRegister(index);
// Set done to true, since it's guaranteed to be true by the time the
// array fill completes.
builder()->LoadTrue().StoreAccumulatorInRegister(done);
// Fill the array with the iterator.
FeedbackSlot element_slot =
feedback_spec()->AddStoreInArrayLiteralICSlot();
FeedbackSlot index_slot = feedback_spec()->AddBinaryOpICSlot();
BuildFillArrayWithIterator(iterator, array, index, next_result,
next_value_load_slot, next_done_load_slot,
index_slot, element_slot);
builder()->Bind(&is_done);
// Assign the array to the LHS.
builder()->LoadAccumulatorWithRegister(array);
BuildAssignment(lhs_data, op, lookup_hoisting_mode);
}
},
// Finally block.
[&](Register iteration_continuation_token,
Register iteration_continuation_result, Register message) {
// Finish the iteration in the finally block.
BuildFinalizeIteration(iterator, done, iteration_continuation_token);
},
HandlerTable::UNCAUGHT);
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
}
// Convert a destructuring assignment to an object literal into a sequence of
// property accesses into the value being assigned (in the accumulator).
//
// { y, [x++]: a(), ...b.c } = value
//
// becomes
//
// var rest_runtime_callargs = new Array(3);
// rest_runtime_callargs[0] = value;
//
// rest_runtime_callargs[1] = "y";
// y = value.y;
//
// var temp1 = %ToName(x++);
// rest_runtime_callargs[2] = temp1;
// a() = value[temp1];
//
// b.c =
// %CopyDataPropertiesWithExcludedPropertiesOnStack.call(rest_runtime_callargs);
void BytecodeGenerator::BuildDestructuringObjectAssignment(
ObjectLiteral* pattern, Token::Value op,
LookupHoistingMode lookup_hoisting_mode) {
RegisterAllocationScope register_scope(this);
// Store the assignment value in a register.
Register value;
RegisterList rest_runtime_callargs;
if (pattern->builder()->has_rest_property()) {
rest_runtime_callargs =
register_allocator()->NewRegisterList(pattern->properties()->length());
value = rest_runtime_callargs[0];
} else {
value = register_allocator()->NewRegister();
}
builder()->StoreAccumulatorInRegister(value);
// if (value === null || value === undefined)
// throw new TypeError(kNonCoercible);
//
// Since the first property access on null/undefined will also trigger a
// TypeError, we can elide this check. The exception is when there are no
// properties and no rest property (this is an empty literal), or when the
// first property is a computed name and accessing it can have side effects.
//
// TODO(leszeks): Also eliminate this check if the value is known to be
// non-null (e.g. an object literal).
if (pattern->properties()->is_empty() ||
(pattern->properties()->at(0)->is_computed_name() &&
pattern->properties()->at(0)->kind() != ObjectLiteralProperty::SPREAD)) {
BytecodeLabel is_null_or_undefined, not_null_or_undefined;
builder()
->JumpIfUndefinedOrNull(&is_null_or_undefined)
.Jump(&not_null_or_undefined);
{
builder()->Bind(&is_null_or_undefined);
builder()->SetExpressionPosition(pattern);
builder()->CallRuntime(Runtime::kThrowPatternAssignmentNonCoercible,
value);
}
builder()->Bind(&not_null_or_undefined);
}
int i = 0;
for (ObjectLiteralProperty* pattern_property : *pattern->properties()) {
RegisterAllocationScope inner_register_scope(this);
// The key of the pattern becomes the key into the RHS value, and the value
// of the pattern becomes the target of the assignment.
//
// e.g. { a: b } = o becomes b = o.a
Expression* pattern_key = pattern_property->key();
Expression* target = pattern_property->value();
Expression* default_value = GetDestructuringDefaultValue(&target);
builder()->SetExpressionPosition(target);
// Calculate this property's key into the assignment RHS value, additionally
// storing the key for rest_runtime_callargs if needed.
//
// The RHS is accessed using the key either by LoadNamedProperty (if
// value_name is valid) or by LoadKeyedProperty (otherwise).
const AstRawString* value_name = nullptr;
Register value_key;
if (pattern_property->kind() != ObjectLiteralProperty::Kind::SPREAD) {
if (pattern_key->IsPropertyName()) {
value_name = pattern_key->AsLiteral()->AsRawPropertyName();
}
if (pattern->builder()->has_rest_property() || !value_name) {
if (pattern->builder()->has_rest_property()) {
value_key = rest_runtime_callargs[i + 1];
} else {
value_key = register_allocator()->NewRegister();
}
if (pattern_property->is_computed_name()) {
// { [a()]: b().x } = c
// becomes
// var tmp = a()
// b().x = c[tmp]
DCHECK(!pattern_key->IsPropertyName() ||
!pattern_key->IsNumberLiteral());
VisitForAccumulatorValue(pattern_key);
builder()->ToName().StoreAccumulatorInRegister(value_key);
} else {
// We only need the key for non-computed properties when it is numeric
// or is being saved for the rest_runtime_callargs.
DCHECK(pattern_key->IsNumberLiteral() ||
(pattern->builder()->has_rest_property() &&
pattern_key->IsPropertyName()));
VisitForRegisterValue(pattern_key, value_key);
}
}
}
AssignmentLhsData lhs_data = PrepareAssignmentLhs(target);
// Get the value from the RHS.
if (pattern_property->kind() == ObjectLiteralProperty::Kind::SPREAD) {
DCHECK_EQ(i, pattern->properties()->length() - 1);
DCHECK(!value_key.is_valid());
DCHECK_NULL(value_name);
builder()->CallRuntime(
Runtime::kInlineCopyDataPropertiesWithExcludedPropertiesOnStack,
rest_runtime_callargs);
} else if (value_name) {
builder()->LoadNamedProperty(
value, value_name, feedback_index(feedback_spec()->AddLoadICSlot()));
} else {
DCHECK(value_key.is_valid());
builder()->LoadAccumulatorWithRegister(value_key).LoadKeyedProperty(
value, feedback_index(feedback_spec()->AddKeyedLoadICSlot()));
}
// {<pattern> = <init>} = <value>
// becomes
// temp = <value>;
// <pattern> = temp === undefined ? <init> : temp;
if (default_value) {
BytecodeLabel value_not_undefined;
builder()->JumpIfNotUndefined(&value_not_undefined);
VisitInHoleCheckElisionScopeForAccumulatorValue(default_value);
builder()->Bind(&value_not_undefined);
}
BuildAssignment(lhs_data, op, lookup_hoisting_mode);
i++;
}
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
}
void BytecodeGenerator::BuildAssignment(
const AssignmentLhsData& lhs_data, Token::Value op,
LookupHoistingMode lookup_hoisting_mode) {
// Assign the value to the LHS.
switch (lhs_data.assign_type()) {
case NON_PROPERTY: {
if (ObjectLiteral* pattern_as_object =
lhs_data.expr()->AsObjectLiteral()) {
// Split object literals into destructuring.
BuildDestructuringObjectAssignment(pattern_as_object, op,
lookup_hoisting_mode);
} else if (ArrayLiteral* pattern_as_array =
lhs_data.expr()->AsArrayLiteral()) {
// Split object literals into destructuring.
BuildDestructuringArrayAssignment(pattern_as_array, op,
lookup_hoisting_mode);
} else {
DCHECK(lhs_data.expr()->IsVariableProxy());
VariableProxy* proxy = lhs_data.expr()->AsVariableProxy();
BuildVariableAssignment(proxy->var(), op, proxy->hole_check_mode(),
lookup_hoisting_mode);
}
break;
}
case NAMED_PROPERTY: {
BuildSetNamedProperty(lhs_data.object_expr(), lhs_data.object(),
lhs_data.name());
break;
}
case KEYED_PROPERTY: {
FeedbackSlot slot = feedback_spec()->AddKeyedStoreICSlot(language_mode());
Register value;
if (!execution_result()->IsEffect()) {
value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
}
builder()->SetKeyedProperty(lhs_data.object(), lhs_data.key(),
feedback_index(slot), language_mode());
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
break;
}
case NAMED_SUPER_PROPERTY: {
builder()
->StoreAccumulatorInRegister(lhs_data.super_property_args()[3])
.CallRuntime(Runtime::kStoreToSuper, lhs_data.super_property_args());
break;
}
case KEYED_SUPER_PROPERTY: {
builder()
->StoreAccumulatorInRegister(lhs_data.super_property_args()[3])
.CallRuntime(Runtime::kStoreKeyedToSuper,
lhs_data.super_property_args());
break;
}
case PRIVATE_METHOD: {
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateBrandCheck(property, lhs_data.object());
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateMethodWrite,
lhs_data.expr()->AsProperty());
break;
}
case PRIVATE_GETTER_ONLY: {
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateBrandCheck(property, lhs_data.object());
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateSetterAccess,
lhs_data.expr()->AsProperty());
break;
}
case PRIVATE_SETTER_ONLY:
case PRIVATE_GETTER_AND_SETTER: {
Register value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateBrandCheck(property, lhs_data.object());
BuildPrivateSetterAccess(lhs_data.object(), lhs_data.key(), value);
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
break;
}
case PRIVATE_DEBUG_DYNAMIC: {
Register value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateDebugDynamicSet(property, lhs_data.object(), value);
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
break;
}
}
}
void BytecodeGenerator::VisitAssignment(Assignment* expr) {
AssignmentLhsData lhs_data = PrepareAssignmentLhs(expr->target());
VisitForAccumulatorValue(expr->value());
builder()->SetExpressionPosition(expr);
BuildAssignment(lhs_data, expr->op(), expr->lookup_hoisting_mode());
}
void BytecodeGenerator::VisitCompoundAssignment(CompoundAssignment* expr) {
AssignmentLhsData lhs_data = PrepareAssignmentLhs(expr->target());
// Evaluate the value and potentially handle compound assignments by loading
// the left-hand side value and performing a binary operation.
switch (lhs_data.assign_type()) {
case NON_PROPERTY: {
VariableProxy* proxy = expr->target()->AsVariableProxy();
BuildVariableLoad(proxy->var(), proxy->hole_check_mode());
break;
}
case NAMED_PROPERTY: {
BuildLoadNamedProperty(lhs_data.object_expr(), lhs_data.object(),
lhs_data.name());
break;
}
case KEYED_PROPERTY: {
FeedbackSlot slot = feedback_spec()->AddKeyedLoadICSlot();
builder()->LoadAccumulatorWithRegister(lhs_data.key());
BuildLoadKeyedProperty(lhs_data.object(), slot);
break;
}
case NAMED_SUPER_PROPERTY: {
builder()->CallRuntime(Runtime::kLoadFromSuper,
lhs_data.super_property_args().Truncate(3));
break;
}
case KEYED_SUPER_PROPERTY: {
builder()->CallRuntime(Runtime::kLoadKeyedFromSuper,
lhs_data.super_property_args().Truncate(3));
break;
}
// BuildAssignment() will throw an error about the private method being
// read-only.
case PRIVATE_METHOD: {
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateBrandCheck(property, lhs_data.object());
builder()->LoadAccumulatorWithRegister(lhs_data.key());
break;
}
// For read-only properties, BuildAssignment() will throw an error about
// the missing setter.
case PRIVATE_GETTER_ONLY:
case PRIVATE_GETTER_AND_SETTER: {
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateBrandCheck(property, lhs_data.object());
BuildPrivateGetterAccess(lhs_data.object(), lhs_data.key());
break;
}
case PRIVATE_SETTER_ONLY: {
// The property access is invalid, but if the brand check fails too, we
// need to return the error from the brand check.
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateBrandCheck(property, lhs_data.object());
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateGetterAccess,
lhs_data.expr()->AsProperty());
break;
}
case PRIVATE_DEBUG_DYNAMIC: {
Property* property = lhs_data.expr()->AsProperty();
BuildPrivateDebugDynamicGet(property, lhs_data.object());
break;
}
}
BinaryOperation* binop = expr->binary_operation();
FeedbackSlot slot = feedback_spec()->AddBinaryOpICSlot();
BytecodeLabel short_circuit;
if (binop->op() == Token::kNullish) {
BytecodeLabel nullish;
builder()
->JumpIfUndefinedOrNull(&nullish)
.Jump(&short_circuit)
.Bind(&nullish);
VisitInHoleCheckElisionScopeForAccumulatorValue(expr->value());
} else if (binop->op() == Token::kOr) {
builder()->JumpIfTrue(ToBooleanMode::kConvertToBoolean, &short_circuit);
VisitInHoleCheckElisionScopeForAccumulatorValue(expr->value());
} else if (binop->op() == Token::kAnd) {
builder()->JumpIfFalse(ToBooleanMode::kConvertToBoolean, &short_circuit);
VisitInHoleCheckElisionScopeForAccumulatorValue(expr->value());
} else if (expr->value()->IsSmiLiteral()) {
builder()->BinaryOperationSmiLiteral(
binop->op(), expr->value()->AsLiteral()->AsSmiLiteral(),
feedback_index(slot));
} else {
Register old_value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(old_value);
VisitForAccumulatorValue(expr->value());
builder()->BinaryOperation(binop->op(), old_value, feedback_index(slot));
}
builder()->SetExpressionPosition(expr);
BuildAssignment(lhs_data, expr->op(), expr->lookup_hoisting_mode());
builder()->Bind(&short_circuit);
}
// Suspends the generator to resume at the next suspend_id, with output stored
// in the accumulator. When the generator is resumed, the sent value is loaded
// in the accumulator.
void BytecodeGenerator::BuildSuspendPoint(int position) {
// Because we eliminate jump targets in dead code, we also eliminate resumes
// when the suspend is not emitted because otherwise the below call to Bind
// would start a new basic block and the code would be considered alive.
if (builder()->RemainderOfBlockIsDead()) {
return;
}
const int suspend_id = suspend_count_++;
RegisterList registers = register_allocator()->AllLiveRegisters();
// Save context, registers, and state. This bytecode then returns the value
// in the accumulator.
builder()->SetExpressionPosition(position);
builder()->SuspendGenerator(generator_object(), registers, suspend_id);
// Upon resume, we continue here.
builder()->Bind(generator_jump_table_, suspend_id);
// Clobbers all registers and sets the accumulator to the
// [[input_or_debug_pos]] slot of the generator object.
builder()->ResumeGenerator(generator_object(), registers);
}
void BytecodeGenerator::VisitYield(Yield* expr) {
builder()->SetExpressionPosition(expr);
VisitForAccumulatorValue(expr->expression());
bool is_async = IsAsyncGeneratorFunction(function_kind());
// If this is not the first yield
if (suspend_count_ > 0) {
if (is_async) {
// AsyncGenerator yields (with the exception of the initial yield)
// delegate work to the AsyncGeneratorYieldWithAwait stub, which Awaits
// the operand and on success, wraps the value in an IteratorResult.
//
// In the spec the Await is a separate operation, but they are combined
// here to reduce bytecode size.
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(generator_object(), args[0]) // generator
.StoreAccumulatorInRegister(args[1]) // value
.CallRuntime(Runtime::kInlineAsyncGeneratorYieldWithAwait, args);
} else {
// Generator yields (with the exception of the initial yield) wrap the
// value into IteratorResult.
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->StoreAccumulatorInRegister(args[0]) // value
.LoadFalse()
.StoreAccumulatorInRegister(args[1]) // done
.CallRuntime(Runtime::kInlineCreateIterResultObject, args);
}
}
BuildSuspendPoint(expr->position());
// At this point, the generator has been resumed, with the received value in
// the accumulator.
// TODO(caitp): remove once yield* desugaring for async generators is handled
// in BytecodeGenerator.
if (expr->on_abrupt_resume() == Yield::kNoControl) {
DCHECK(is_async);
return;
}
Register input = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(input).CallRuntime(
Runtime::kInlineGeneratorGetResumeMode, generator_object());
// Now dispatch on resume mode.
static_assert(JSGeneratorObject::kNext + 1 == JSGeneratorObject::kReturn);
static_assert(JSGeneratorObject::kReturn + 1 == JSGeneratorObject::kThrow);
BytecodeJumpTable* jump_table =
builder()->AllocateJumpTable(is_async ? 3 : 2, JSGeneratorObject::kNext);
builder()->SwitchOnSmiNoFeedback(jump_table);
if (is_async) {
// Resume with rethrow (switch fallthrough).
// This case is only necessary in async generators.
builder()->SetExpressionPosition(expr);
builder()->LoadAccumulatorWithRegister(input);
builder()->ReThrow();
// Add label for kThrow (next case).
builder()->Bind(jump_table, JSGeneratorObject::kThrow);
}
{
// Resume with throw (switch fallthrough in sync case).
// TODO(leszeks): Add a debug-only check that the accumulator is
// JSGeneratorObject::kThrow.
builder()->SetExpressionPosition(expr);
builder()->LoadAccumulatorWithRegister(input);
builder()->Throw();
}
{
// Resume with return.
builder()->Bind(jump_table, JSGeneratorObject::kReturn);
builder()->LoadAccumulatorWithRegister(input);
if (is_async) {
execution_control()->AsyncReturnAccumulator(kNoSourcePosition);
} else {
execution_control()->ReturnAccumulator(kNoSourcePosition);
}
}
{
// Resume with next.
builder()->Bind(jump_table, JSGeneratorObject::kNext);
BuildIncrementBlockCoverageCounterIfEnabled(expr,
SourceRangeKind::kContinuation);
builder()->LoadAccumulatorWithRegister(input);
}
}
// Desugaring of (yield* iterable)
//
// do {
// const kNext = 0;
// const kReturn = 1;
// const kThrow = 2;
//
// let output; // uninitialized
//
// let iteratorRecord = GetIterator(iterable);
// let iterator = iteratorRecord.[[Iterator]];
// let next = iteratorRecord.[[NextMethod]];
// let input = undefined;
// let resumeMode = kNext;
//
// while (true) {
// // From the generator to the iterator:
// // Forward input according to resumeMode and obtain output.
// switch (resumeMode) {
// case kNext:
// output = next.[[Call]](iterator, « »);;
// break;
// case kReturn:
// let iteratorReturn = iterator.return;
// if (IS_NULL_OR_UNDEFINED(iteratorReturn)) {
// if (IS_ASYNC_GENERATOR) input = await input;
// return input;
// }
// output = iteratorReturn.[[Call]](iterator, «input»);
// break;
// case kThrow:
// let iteratorThrow = iterator.throw;
// if (IS_NULL_OR_UNDEFINED(iteratorThrow)) {
// let iteratorReturn = iterator.return;
// if (!IS_NULL_OR_UNDEFINED(iteratorReturn)) {
// output = iteratorReturn.[[Call]](iterator, « »);
// if (IS_ASYNC_GENERATOR) output = await output;
// if (!IS_RECEIVER(output)) %ThrowIterResultNotAnObject(output);
// }
// throw MakeTypeError(kThrowMethodMissing);
// }
// output = iteratorThrow.[[Call]](iterator, «input»);
// break;
// }
//
// if (IS_ASYNC_GENERATOR) output = await output;
// if (!IS_RECEIVER(output)) %ThrowIterResultNotAnObject(output);
// if (output.done) break;
//
// // From the generator to its user:
// // Forward output, receive new input, and determine resume mode.
// if (IS_ASYNC_GENERATOR) {
// // Resolve the promise for the current AsyncGeneratorRequest.
// %_AsyncGeneratorResolve(output.value, /* done = */ false)
// }
// input = Suspend(output);
// resumeMode = %GeneratorGetResumeMode();
// }
//
// if (resumeMode === kReturn) {
// return output.value;
// }
// output.value
// }
void BytecodeGenerator::VisitYieldStar(YieldStar* expr) {
Register output = register_allocator()->NewRegister();
Register resume_mode = register_allocator()->NewRegister();
IteratorType iterator_type = IsAsyncGeneratorFunction(function_kind())
? IteratorType::kAsync
: IteratorType::kNormal;
{
RegisterAllocationScope register_scope(this);
RegisterList iterator_and_input = register_allocator()->NewRegisterList(2);
VisitForAccumulatorValue(expr->expression());
IteratorRecord iterator = BuildGetIteratorRecord(
register_allocator()->NewRegister() /* next method */,
iterator_and_input[0], iterator_type);
Register input = iterator_and_input[1];
builder()->LoadUndefined().StoreAccumulatorInRegister(input);
builder()
->LoadLiteral(Smi::FromInt(JSGeneratorObject::kNext))
.StoreAccumulatorInRegister(resume_mode);
{
// This loop builder does not construct counters as the loop is not
// visible to the user, and we therefore neither pass the block coverage
// builder nor the expression.
//
// In addition to the normal suspend for yield*, a yield* in an async
// generator has 2 additional suspends:
// - One for awaiting the iterator result of closing the generator when
// resumed with a "throw" completion, and a throw method is not
// present on the delegated iterator
// - One for awaiting the iterator result yielded by the delegated
// iterator
LoopBuilder loop_builder(builder(), nullptr, nullptr, feedback_spec());
LoopScope loop_scope(this, &loop_builder);
{
BytecodeLabels after_switch(zone());
BytecodeJumpTable* switch_jump_table =
builder()->AllocateJumpTable(2, 1);
builder()
->LoadAccumulatorWithRegister(resume_mode)
.SwitchOnSmiNoFeedback(switch_jump_table);
// Fallthrough to default case.
// TODO(ignition): Add debug code to check that {resume_mode} really is
// {JSGeneratorObject::kNext} in this case.
static_assert(JSGeneratorObject::kNext == 0);
{
FeedbackSlot slot = feedback_spec()->AddCallICSlot();
builder()->CallProperty(iterator.next(), iterator_and_input,
feedback_index(slot));
builder()->Jump(after_switch.New());
}
static_assert(JSGeneratorObject::kReturn == 1);
builder()->Bind(switch_jump_table, JSGeneratorObject::kReturn);
{
const AstRawString* return_string =
ast_string_constants()->return_string();
BytecodeLabels no_return_method(zone());
BuildCallIteratorMethod(iterator.object(), return_string,
iterator_and_input, after_switch.New(),
&no_return_method);
no_return_method.Bind(builder());
builder()->LoadAccumulatorWithRegister(input);
if (iterator_type == IteratorType::kAsync) {
// Await input.
BuildAwait(expr->position());
execution_control()->AsyncReturnAccumulator(kNoSourcePosition);
} else {
execution_control()->ReturnAccumulator(kNoSourcePosition);
}
}
static_assert(JSGeneratorObject::kThrow == 2);
builder()->Bind(switch_jump_table, JSGeneratorObject::kThrow);
{
const AstRawString* throw_string =
ast_string_constants()->throw_string();
BytecodeLabels no_throw_method(zone());
BuildCallIteratorMethod(iterator.object(), throw_string,
iterator_and_input, after_switch.New(),
&no_throw_method);
// If there is no "throw" method, perform IteratorClose, and finally
// throw a TypeError.
no_throw_method.Bind(builder());
BuildIteratorClose(iterator, expr);
builder()->CallRuntime(Runtime::kThrowThrowMethodMissing);
}
after_switch.Bind(builder());
}
if (iterator_type == IteratorType::kAsync) {
// Await the result of the method invocation.
BuildAwait(expr->position());
}
// Check that output is an object.
BytecodeLabel check_if_done;
builder()
->StoreAccumulatorInRegister(output)
.JumpIfJSReceiver(&check_if_done)
.CallRuntime(Runtime::kThrowIteratorResultNotAnObject, output);
builder()->Bind(&check_if_done);
// Break once output.done is true.
builder()->LoadNamedProperty(
output, ast_string_constants()->done_string(),
feedback_index(feedback_spec()->AddLoadICSlot()));
loop_builder.BreakIfTrue(ToBooleanMode::kConvertToBoolean);
// Suspend the current generator.
if (iterator_type == IteratorType::kNormal) {
builder()->LoadAccumulatorWithRegister(output);
} else {
RegisterAllocationScope inner_register_scope(this);
DCHECK_EQ(iterator_type, IteratorType::kAsync);
// If generatorKind is async, perform
// AsyncGeneratorResolve(output.value, /* done = */ false), which will
// resolve the current AsyncGeneratorRequest's promise with
// output.value.
builder()->LoadNamedProperty(
output, ast_string_constants()->value_string(),
feedback_index(feedback_spec()->AddLoadICSlot()));
RegisterList args = register_allocator()->NewRegisterList(3);
builder()
->MoveRegister(generator_object(), args[0]) // generator
.StoreAccumulatorInRegister(args[1]) // value
.LoadFalse()
.StoreAccumulatorInRegister(args[2]) // done
.CallRuntime(Runtime::kInlineAsyncGeneratorResolve, args);
}
BuildSuspendPoint(expr->position());
builder()->StoreAccumulatorInRegister(input);
builder()
->CallRuntime(Runtime::kInlineGeneratorGetResumeMode,
generator_object())
.StoreAccumulatorInRegister(resume_mode);
loop_builder.BindContinueTarget();
}
}
// Decide if we trigger a return or if the yield* expression should just
// produce a value.
BytecodeLabel completion_is_output_value;
Register output_value = register_allocator()->NewRegister();
builder()
->LoadNamedProperty(output, ast_string_constants()->value_string(),
feedback_index(feedback_spec()->AddLoadICSlot()))
.StoreAccumulatorInRegister(output_value)
.LoadLiteral(Smi::FromInt(JSGeneratorObject::kReturn))
.CompareReference(resume_mode)
.JumpIfFalse(ToBooleanMode::kAlreadyBoolean, &completion_is_output_value)
.LoadAccumulatorWithRegister(output_value);
if (iterator_type == IteratorType::kAsync) {
execution_control()->AsyncReturnAccumulator(kNoSourcePosition);
} else {
execution_control()->ReturnAccumulator(kNoSourcePosition);
}
builder()->Bind(&completion_is_output_value);
BuildIncrementBlockCoverageCounterIfEnabled(expr,
SourceRangeKind::kContinuation);
builder()->LoadAccumulatorWithRegister(output_value);
}
void BytecodeGenerator::BuildAwait(int position) {
// Rather than HandlerTable::UNCAUGHT, async functions use
// HandlerTable::ASYNC_AWAIT to communicate that top-level exceptions are
// transformed into promise rejections. This is necessary to prevent emitting
// multiple debug events for the same uncaught exception. There is no point
// in the body of an async function where catch prediction is
// HandlerTable::UNCAUGHT.
DCHECK(catch_prediction() != HandlerTable::UNCAUGHT ||
info()->scope()->is_repl_mode_scope());
{
// Await(operand) and suspend.
RegisterAllocationScope register_scope(this);
Runtime::FunctionId await_intrinsic_id;
if (IsAsyncGeneratorFunction(function_kind())) {
await_intrinsic_id = Runtime::kInlineAsyncGeneratorAwait;
} else {
await_intrinsic_id = Runtime::kInlineAsyncFunctionAwait;
}
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->MoveRegister(generator_object(), args[0])
.StoreAccumulatorInRegister(args[1])
.CallRuntime(await_intrinsic_id, args);
}
BuildSuspendPoint(position);
Register input = register_allocator()->NewRegister();
Register resume_mode = register_allocator()->NewRegister();
// Now dispatch on resume mode.
BytecodeLabel resume_next;
builder()
->StoreAccumulatorInRegister(input)
.CallRuntime(Runtime::kInlineGeneratorGetResumeMode, generator_object())
.StoreAccumulatorInRegister(resume_mode)
.LoadLiteral(Smi::FromInt(JSGeneratorObject::kNext))
.CompareReference(resume_mode)
.JumpIfTrue(ToBooleanMode::kAlreadyBoolean, &resume_next);
// Resume with "throw" completion (rethrow the received value).
// TODO(leszeks): Add a debug-only check that the accumulator is
// JSGeneratorObject::kThrow.
builder()->LoadAccumulatorWithRegister(input).ReThrow();
// Resume with next.
builder()->Bind(&resume_next);
builder()->LoadAccumulatorWithRegister(input);
}
void BytecodeGenerator::VisitAwait(Await* expr) {
builder()->SetExpressionPosition(expr);
VisitForAccumulatorValue(expr->expression());
BuildAwait(expr->position());
BuildIncrementBlockCoverageCounterIfEnabled(expr,
SourceRangeKind::kContinuation);
}
void BytecodeGenerator::VisitThrow(Throw* expr) {
AllocateBlockCoverageSlotIfEnabled(expr, SourceRangeKind::kContinuation);
VisitForAccumulatorValue(expr->exception());
builder()->SetExpressionPosition(expr);
builder()->Throw();
}
void BytecodeGenerator::VisitPropertyLoad(Register obj, Property* property) {
if (property->is_optional_chain_link()) {
DCHECK_NOT_NULL(optional_chaining_null_labels_);
int right_range =
AllocateBlockCoverageSlotIfEnabled(property, SourceRangeKind::kRight);
builder()->LoadAccumulatorWithRegister(obj).JumpIfUndefinedOrNull(
optional_chaining_null_labels_->New());
BuildIncrementBlockCoverageCounterIfEnabled(right_range);
}
AssignType property_kind = Property::GetAssignType(property);
switch (property_kind) {
case NON_PROPERTY:
UNREACHABLE();
case NAMED_PROPERTY: {
builder()->SetExpressionPosition(property);
const AstRawString* name =
property->key()->AsLiteral()->AsRawPropertyName();
BuildLoadNamedProperty(property->obj(), obj, name);
break;
}
case KEYED_PROPERTY: {
VisitForAccumulatorValueAsPropertyKey(property->key());
builder()->SetExpressionPosition(property);
BuildLoadKeyedProperty(obj, feedback_spec()->AddKeyedLoadICSlot());
break;
}
case NAMED_SUPER_PROPERTY:
VisitNamedSuperPropertyLoad(property, Register::invalid_value());
break;
case KEYED_SUPER_PROPERTY:
VisitKeyedSuperPropertyLoad(property, Register::invalid_value());
break;
case PRIVATE_SETTER_ONLY: {
BuildPrivateBrandCheck(property, obj);
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateGetterAccess,
property);
break;
}
case PRIVATE_GETTER_ONLY:
case PRIVATE_GETTER_AND_SETTER: {
Register key = VisitForRegisterValue(property->key());
BuildPrivateBrandCheck(property, obj);
BuildPrivateGetterAccess(obj, key);
break;
}
case PRIVATE_METHOD: {
BuildPrivateBrandCheck(property, obj);
// In the case of private methods, property->key() is the function to be
// loaded (stored in a context slot), so load this directly.
VisitForAccumulatorValue(property->key());
break;
}
case PRIVATE_DEBUG_DYNAMIC: {
BuildPrivateDebugDynamicGet(property, obj);
break;
}
}
}
void BytecodeGenerator::BuildPrivateDebugDynamicGet(Property* property,
Register obj) {
RegisterAllocationScope scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
Variable* private_name = property->key()->AsVariableProxy()->var();
builder()
->MoveRegister(obj, args[0])
.LoadLiteral(private_name->raw_name())
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kGetPrivateMember, args);
}
void BytecodeGenerator::BuildPrivateDebugDynamicSet(Property* property,
Register obj,
Register value) {
RegisterAllocationScope scope(this);
RegisterList args = register_allocator()->NewRegisterList(3);
Variable* private_name = property->key()->AsVariableProxy()->var();
builder()
->MoveRegister(obj, args[0])
.LoadLiteral(private_name->raw_name())
.StoreAccumulatorInRegister(args[1])
.MoveRegister(value, args[2])
.CallRuntime(Runtime::kSetPrivateMember, args);
}
void BytecodeGenerator::BuildPrivateGetterAccess(Register object,
Register accessor_pair) {
RegisterAllocationScope scope(this);
Register accessor = register_allocator()->NewRegister();
RegisterList args = register_allocator()->NewRegisterList(1);
builder()
->CallRuntime(Runtime::kLoadPrivateGetter, accessor_pair)
.StoreAccumulatorInRegister(accessor)
.MoveRegister(object, args[0])
.CallProperty(accessor, args,
feedback_index(feedback_spec()->AddCallICSlot()));
}
void BytecodeGenerator::BuildPrivateSetterAccess(Register object,
Register accessor_pair,
Register value) {
RegisterAllocationScope scope(this);
Register accessor = register_allocator()->NewRegister();
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->CallRuntime(Runtime::kLoadPrivateSetter, accessor_pair)
.StoreAccumulatorInRegister(accessor)
.MoveRegister(object, args[0])
.MoveRegister(value, args[1])
.CallProperty(accessor, args,
feedback_index(feedback_spec()->AddCallICSlot()));
}
void BytecodeGenerator::BuildPrivateMethodIn(Variable* private_name,
Expression* object_expression) {
DCHECK(IsPrivateMethodOrAccessorVariableMode(private_name->mode()));
ClassScope* scope = private_name->scope()->AsClassScope();
if (private_name->is_static()) {
// For static private methods, "#privatemethod in ..." only returns true for
// the class constructor.
if (scope->class_variable() == nullptr) {
// Can only happen via the debugger. See comment in
// BuildPrivateBrandCheck.
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->LoadLiteral(Smi::FromEnum(
MessageTemplate::
kInvalidUnusedPrivateStaticMethodAccessedByDebugger))
.StoreAccumulatorInRegister(args[0])
.LoadLiteral(private_name->raw_name())
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kNewError, args)
.Throw();
} else {
VisitForAccumulatorValue(object_expression);
Register object = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(object);
BytecodeLabel is_object;
builder()->JumpIfJSReceiver(&is_object);
RegisterList args = register_allocator()->NewRegisterList(3);
builder()
->StoreAccumulatorInRegister(args[2])
.LoadLiteral(Smi::FromEnum(MessageTemplate::kInvalidInOperatorUse))
.StoreAccumulatorInRegister(args[0])
.LoadLiteral(private_name->raw_name())
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kNewTypeError, args)
.Throw();
builder()->Bind(&is_object);
BuildVariableLoadForAccumulatorValue(scope->class_variable(),
HoleCheckMode::kElided);
builder()->CompareReference(object);
}
} else {
BuildVariableLoadForAccumulatorValue(scope->brand(),
HoleCheckMode::kElided);
Register brand = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(brand);
VisitForAccumulatorValue(object_expression);
builder()->SetExpressionPosition(object_expression);
FeedbackSlot slot = feedback_spec()->AddKeyedHasICSlot();
builder()->CompareOperation(Token::kIn, brand, feedback_index(slot));
execution_result()->SetResultIsBoolean();
}
}
void BytecodeGenerator::BuildPrivateBrandCheck(Property* property,
Register object) {
Variable* private_name = property->key()->AsVariableProxy()->var();
DCHECK(IsPrivateMethodOrAccessorVariableMode(private_name->mode()));
ClassScope* scope = private_name->scope()->AsClassScope();
builder()->SetExpressionPosition(property);
if (private_name->is_static()) {
// For static private methods, the only valid receiver is the class.
// Load the class constructor.
if (scope->class_variable() == nullptr) {
// If the static private method has not been used used in source
// code (either explicitly or through the presence of eval), but is
// accessed by the debugger at runtime, reference to the class variable
// is not available since it was not be context-allocated. Therefore we
// can't build a branch check, and throw an ReferenceError as if the
// method was optimized away.
// TODO(joyee): get a reference to the class constructor through
// something other than scope->class_variable() in this scenario.
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->LoadLiteral(Smi::FromEnum(
MessageTemplate::
kInvalidUnusedPrivateStaticMethodAccessedByDebugger))
.StoreAccumulatorInRegister(args[0])
.LoadLiteral(private_name->raw_name())
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kNewError, args)
.Throw();
} else {
BuildVariableLoadForAccumulatorValue(scope->class_variable(),
HoleCheckMode::kElided);
BytecodeLabel return_check;
builder()->CompareReference(object).JumpIfTrue(
ToBooleanMode::kAlreadyBoolean, &return_check);
const AstRawString* name = scope->class_variable()->raw_name();
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
builder()
->LoadLiteral(
Smi::FromEnum(MessageTemplate::kInvalidPrivateBrandStatic))
.StoreAccumulatorInRegister(args[0])
.LoadLiteral(name)
.StoreAccumulatorInRegister(args[1])
.CallRuntime(Runtime::kNewTypeError, args)
.Throw();
builder()->Bind(&return_check);
}
} else {
BuildVariableLoadForAccumulatorValue(scope->brand(),
HoleCheckMode::kElided);
builder()->LoadKeyedProperty(
object, feedback_index(feedback_spec()->AddKeyedLoadICSlot()));
}
}
void BytecodeGenerator::VisitPropertyLoadForRegister(Register obj,
Property* expr,
Register destination) {
ValueResultScope result_scope(this);
VisitPropertyLoad(obj, expr);
builder()->StoreAccumulatorInRegister(destination);
}
void BytecodeGenerator::VisitNamedSuperPropertyLoad(Property* property,
Register opt_receiver_out) {
RegisterAllocationScope register_scope(this);
if (v8_flags.super_ic) {
Register receiver = register_allocator()->NewRegister();
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(receiver);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->SetExpressionPosition(property);
auto name = property->key()->AsLiteral()->AsRawPropertyName();
FeedbackSlot slot = GetCachedLoadSuperICSlot(name);
builder()->LoadNamedPropertyFromSuper(receiver, name, feedback_index(slot));
if (opt_receiver_out.is_valid()) {
builder()->MoveRegister(receiver, opt_receiver_out);
}
} else {
RegisterList args = register_allocator()->NewRegisterList(3);
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(args[0]);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(args[1]);
builder()->SetExpressionPosition(property);
builder()
->LoadLiteral(property->key()->AsLiteral()->AsRawPropertyName())
.StoreAccumulatorInRegister(args[2])
.CallRuntime(Runtime::kLoadFromSuper, args);
if (opt_receiver_out.is_valid()) {
builder()->MoveRegister(args[0], opt_receiver_out);
}
}
}
void BytecodeGenerator::VisitKeyedSuperPropertyLoad(Property* property,
Register opt_receiver_out) {
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(3);
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(args[0]);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(args[1]);
VisitForRegisterValue(property->key(), args[2]);
builder()->SetExpressionPosition(property);
builder()->CallRuntime(Runtime::kLoadKeyedFromSuper, args);
if (opt_receiver_out.is_valid()) {
builder()->MoveRegister(args[0], opt_receiver_out);
}
}
template <typename ExpressionFunc>
void BytecodeGenerator::BuildOptionalChain(ExpressionFunc expression_func) {
BytecodeLabel done;
OptionalChainNullLabelScope label_scope(this);
// Use the same scope for the entire optional chain, as links earlier in the
// chain dominate later links, linearly.
HoleCheckElisionScope elider(this);
expression_func();
builder()->Jump(&done);
label_scope.labels()->Bind(builder());
builder()->LoadUndefined();
builder()->Bind(&done);
}
void BytecodeGenerator::VisitOptionalChain(OptionalChain* expr) {
BuildOptionalChain([&]() { VisitForAccumulatorValue(expr->expression()); });
}
void BytecodeGenerator::VisitProperty(Property* expr) {
AssignType property_kind = Property::GetAssignType(expr);
if (property_kind != NAMED_SUPER_PROPERTY &&
property_kind != KEYED_SUPER_PROPERTY) {
Register obj = VisitForRegisterValue(expr->obj());
VisitPropertyLoad(obj, expr);
} else {
VisitPropertyLoad(Register::invalid_value(), expr);
}
}
void BytecodeGenerator::VisitArguments(const ZonePtrList<Expression>* args,
RegisterList* arg_regs) {
// Visit arguments.
builder()->UpdateMaxArguments(static_cast<uint16_t>(args->length()));
for (int i = 0; i < static_cast<int>(args->length()); i++) {
VisitAndPushIntoRegisterList(args->at(i), arg_regs);
}
}
void BytecodeGenerator::VisitCall(Call* expr) {
Expression* callee_expr = expr->expression();
Call::CallType call_type = expr->GetCallType();
if (call_type == Call::SUPER_CALL) {
return VisitCallSuper(expr);
}
// We compile the call differently depending on the presence of spreads and
// their positions.
//
// If there is only one spread and it is the final argument, there is a
// special CallWithSpread bytecode.
//
// If there is a non-final spread, we rewrite calls like
// callee(1, ...x, 2)
// to
// %reflect_apply(callee, receiver, [1, ...x, 2])
const Call::SpreadPosition spread_position = expr->spread_position();
// Grow the args list as we visit receiver / arguments to avoid allocating all
// the registers up-front. Otherwise these registers are unavailable during
// receiver / argument visiting and we can end up with memory leaks due to
// registers keeping objects alive.
RegisterList args = register_allocator()->NewGrowableRegisterList();
// The callee is the first register in args for ease of calling %reflect_apply
// if we have a non-final spread. For all other cases it is popped from args
// before emitting the call below.
Register callee = register_allocator()->GrowRegisterList(&args);
bool implicit_undefined_receiver = false;
// TODO(petermarshall): We have a lot of call bytecodes that are very similar,
// see if we can reduce the number by adding a separate argument which
// specifies the call type (e.g., property, spread, tailcall, etc.).
// Prepare the callee and the receiver to the function call. This depends on
// the semantics of the underlying call type.
switch (call_type) {
case Call::NAMED_PROPERTY_CALL:
case Call::KEYED_PROPERTY_CALL:
case Call::PRIVATE_CALL: {
Property* property = callee_expr->AsProperty();
VisitAndPushIntoRegisterList(property->obj(), &args);
VisitPropertyLoadForRegister(args.last_register(), property, callee);
break;
}
case Call::GLOBAL_CALL: {
// Receiver is undefined for global calls.
if (spread_position == Call::kNoSpread) {
implicit_undefined_receiver = true;
} else {
// TODO(leszeks): There's no special bytecode for tail calls or spread
// calls with an undefined receiver, so just push undefined ourselves.
BuildPushUndefinedIntoRegisterList(&args);
}
// Load callee as a global variable.
VariableProxy* proxy = callee_expr->AsVariableProxy();
BuildVariableLoadForAccumulatorValue(proxy->var(),
proxy->hole_check_mode());
builder()->StoreAccumulatorInRegister(callee);
break;
}
case Call::WITH_CALL: {
Register receiver = register_allocator()->GrowRegisterList(&args);
DCHECK(callee_expr->AsVariableProxy()->var()->IsLookupSlot());
{
RegisterAllocationScope inner_register_scope(this);
Register name = register_allocator()->NewRegister();
// Call %LoadLookupSlotForCall to get the callee and receiver.
RegisterList result_pair = register_allocator()->NewRegisterList(2);
Variable* variable = callee_expr->AsVariableProxy()->var();
builder()
->LoadLiteral(variable->raw_name())
.StoreAccumulatorInRegister(name)
.CallRuntimeForPair(Runtime::kLoadLookupSlotForCall, name,
result_pair)
.MoveRegister(result_pair[0], callee)
.MoveRegister(result_pair[1], receiver);
}
break;
}
case Call::OTHER_CALL: {
// Receiver is undefined for other calls.
if (spread_position == Call::kNoSpread) {
implicit_undefined_receiver = true;
} else {
// TODO(leszeks): There's no special bytecode for tail calls or spread
// calls with an undefined receiver, so just push undefined ourselves.
BuildPushUndefinedIntoRegisterList(&args);
}
VisitForRegisterValue(callee_expr, callee);
break;
}
case Call::NAMED_SUPER_PROPERTY_CALL: {
Register receiver = register_allocator()->GrowRegisterList(&args);
Property* property = callee_expr->AsProperty();
VisitNamedSuperPropertyLoad(property, receiver);
builder()->StoreAccumulatorInRegister(callee);
break;
}
case Call::KEYED_SUPER_PROPERTY_CALL: {
Register receiver = register_allocator()->GrowRegisterList(&args);
Property* property = callee_expr->AsProperty();
VisitKeyedSuperPropertyLoad(property, receiver);
builder()->StoreAccumulatorInRegister(callee);
break;
}
case Call::NAMED_OPTIONAL_CHAIN_PROPERTY_CALL:
case Call::KEYED_OPTIONAL_CHAIN_PROPERTY_CALL:
case Call::PRIVATE_OPTIONAL_CHAIN_CALL: {
OptionalChain* chain = callee_expr->AsOptionalChain();
Property* property = chain->expression()->AsProperty();
BuildOptionalChain([&]() {
VisitAndPushIntoRegisterList(property->obj(), &args);
VisitPropertyLoad(args.last_register(), property);
});
builder()->StoreAccumulatorInRegister(callee);
break;
}
case Call::SUPER_CALL:
UNREACHABLE();
}
if (expr->is_optional_chain_link()) {
DCHECK_NOT_NULL(optional_chaining_null_labels_);
int right_range =
AllocateBlockCoverageSlotIfEnabled(expr, SourceRangeKind::kRight);
builder()->LoadAccumulatorWithRegister(callee).JumpIfUndefinedOrNull(
optional_chaining_null_labels_->New());
BuildIncrementBlockCoverageCounterIfEnabled(right_range);
}
int receiver_arg_count = -1;
if (spread_position == Call::kHasNonFinalSpread) {
// If we're building %reflect_apply, build the array literal and put it in
// the 3rd argument.
DCHECK(!implicit_undefined_receiver);
DCHECK_EQ(args.register_count(), 2);
BuildCreateArrayLiteral(expr->arguments(), nullptr);
builder()->StoreAccumulatorInRegister(
register_allocator()->GrowRegisterList(&args));
} else {
// If we're not building %reflect_apply and don't need to build an array
// literal, pop the callee and evaluate all arguments to the function call
// and store in sequential args registers.
args = args.PopLeft();
VisitArguments(expr->arguments(), &args);
receiver_arg_count = implicit_undefined_receiver ? 0 : 1;
CHECK_EQ(receiver_arg_count + expr->arguments()->length(),
args.register_count());
}
// Resolve callee for a potential direct eval call. This block will mutate the
// callee value.
if (expr->is_possibly_eval() && expr->arguments()->length() > 0) {
RegisterAllocationScope inner_register_scope(this);
RegisterList runtime_call_args = register_allocator()->NewRegisterList(6);
// Set up arguments for ResolvePossiblyDirectEval by copying callee, source
// strings and function closure, and loading language and
// position.
// Move the first arg.
if (spread_position == Call::kHasNonFinalSpread) {
int feedback_slot_index =
feedback_index(feedback_spec()->AddKeyedLoadICSlot());
Register args_array = args[2];
builder()
->LoadLiteral(Smi::FromInt(0))
.LoadKeyedProperty(args_array, feedback_slot_index)
.StoreAccumulatorInRegister(runtime_call_args[1]);
} else {
// FIXME(v8:5690): Support final spreads for eval.
DCHECK_GE(receiver_arg_count, 0);
builder()->MoveRegister(args[receiver_arg_count], runtime_call_args[1]);
}
Scope* scope_with_context = current_scope();
if (!scope_with_context->NeedsContext()) {
scope_with_context = scope_with_context->GetOuterScopeWithContext();
}
if (scope_with_context) {
eval_calls_.emplace_back(expr, scope_with_context);
}
builder()
->MoveRegister(callee, runtime_call_args[0])
.MoveRegister(Register::function_closure(), runtime_call_args[2])
.LoadLiteral(Smi::FromEnum(language_mode()))
.StoreAccumulatorInRegister(runtime_call_args[3])
.LoadLiteral(Smi::FromInt(expr->eval_scope_info_index()))
.StoreAccumulatorInRegister(runtime_call_args[4])
.LoadLiteral(Smi::FromInt(expr->position()))
.StoreAccumulatorInRegister(runtime_call_args[5]);
// Call ResolvePossiblyDirectEval and modify the callee.
builder()
->CallRuntime(Runtime::kResolvePossiblyDirectEval, runtime_call_args)
.StoreAccumulatorInRegister(callee);
}
builder()->SetExpressionPosition(expr);
if (spread_position == Call::kHasFinalSpread) {
DCHECK(!implicit_undefined_receiver);
builder()->CallWithSpread(callee, args,
feedback_index(feedback_spec()->AddCallICSlot()));
} else if (spread_position == Call::kHasNonFinalSpread) {
builder()->CallJSRuntime(Context::REFLECT_APPLY_INDEX, args);
} else if (call_type == Call::NAMED_PROPERTY_CALL ||
call_type == Call::KEYED_PROPERTY_CALL) {
DCHECK(!implicit_undefined_receiver);
builder()->CallProperty(callee, args,
feedback_index(feedback_spec()->AddCallICSlot()));
} else if (implicit_undefined_receiver) {
builder()->CallUndefinedReceiver(
callee, args, feedback_index(feedback_spec()->AddCallICSlot()));
} else {
builder()->CallAnyReceiver(
callee, args, feedback_index(feedback_spec()->AddCallICSlot()));
}
}
void BytecodeGenerator::VisitCallSuper(Call* expr) {
RegisterAllocationScope register_scope(this);
SuperCallReference* super = expr->expression()->AsSuperCallReference();
const ZonePtrList<Expression>* args = expr->arguments();
// We compile the super call differently depending on the presence of spreads
// and their positions.
//
// If there is only one spread and it is the final argument, there is a
// special ConstructWithSpread bytecode.
//
// It there is a non-final spread, we rewrite something like
// super(1, ...x, 2)
// to
// %reflect_construct(constructor, [1, ...x, 2], new_target)
//
// That is, we implement (non-last-arg) spreads in super calls via our
// mechanism for spreads in array literals.
const Call::SpreadPosition spread_position = expr->spread_position();
// Prepare the constructor to the super call.
Register this_function = VisitForRegisterValue(super->this_function_var());
// This register will initially hold the constructor, then afterward it will
// hold the instance -- the lifetimes of the two don't need to overlap, and
// this way FindNonDefaultConstructorOrConstruct can choose to write either
// the instance or the constructor into the same register.
Register constructor_then_instance = register_allocator()->NewRegister();
BytecodeLabel super_ctor_call_done;
if (spread_position == Call::kHasNonFinalSpread) {
RegisterAllocationScope inner_register_scope(this);
RegisterList construct_args(constructor_then_instance);
const Register& constructor = constructor_then_instance;
// Generate the array containing all arguments.
BuildCreateArrayLiteral(args, nullptr);
Register args_array =
register_allocator()->GrowRegisterList(&construct_args);
builder()->StoreAccumulatorInRegister(args_array);
Register new_target =
register_allocator()->GrowRegisterList(&construct_args);
VisitForRegisterValue(super->new_target_var(), new_target);
BuildGetAndCheckSuperConstructor(this_function, new_target, constructor,
&super_ctor_call_done);
// Now pass that array to %reflect_construct.
builder()->CallJSRuntime(Context::REFLECT_CONSTRUCT_INDEX, construct_args);
} else {
RegisterAllocationScope inner_register_scope(this);
RegisterList args_regs = register_allocator()->NewGrowableRegisterList();
VisitArguments(args, &args_regs);
// The new target is loaded into the new_target register from the
// {new.target} variable.
Register new_target = register_allocator()->NewRegister();
VisitForRegisterValue(super->new_target_var(), new_target);
const Register& constructor = constructor_then_instance;
BuildGetAndCheckSuperConstructor(this_function, new_target, constructor,
&super_ctor_call_done);
builder()->LoadAccumulatorWithRegister(new_target);
builder()->SetExpressionPosition(expr);
int feedback_slot_index = feedback_index(feedback_spec()->AddCallICSlot());
if (spread_position == Call::kHasFinalSpread) {
builder()->ConstructWithSpread(constructor, args_regs,
feedback_slot_index);
} else {
DCHECK_EQ(spread_position, Call::kNoSpread);
// Call construct.
// TODO(turbofan): For now we do gather feedback on super constructor
// calls, utilizing the existing machinery to inline the actual call
// target and the JSCreate for the implicit receiver allocation. This
// is not an ideal solution for super constructor calls, but it gets
// the job done for now. In the long run we might want to revisit this
// and come up with a better way.
builder()->Construct(constructor, args_regs, feedback_slot_index);
}
}
// From here onwards, constructor_then_instance will hold the instance.
const Register& instance = constructor_then_instance;
builder()->StoreAccumulatorInRegister(instance);
builder()->Bind(&super_ctor_call_done);
BuildInstanceInitializationAfterSuperCall(this_function, instance);
builder()->LoadAccumulatorWithRegister(instance);
}
void BytecodeGenerator::BuildInstanceInitializationAfterSuperCall(
Register this_function, Register instance) {
// Explicit calls to the super constructor using super() perform an
// implicit binding assignment to the 'this' variable.
//
// Default constructors don't need have to do the assignment because
// 'this' isn't accessed in default constructors.
if (!IsDefaultConstructor(info()->literal()->kind())) {
Variable* var = closure_scope()->GetReceiverScope()->receiver();
builder()->LoadAccumulatorWithRegister(instance);
BuildVariableAssignment(var, Token::kInit, HoleCheckMode::kRequired);
}
// The constructor scope always needs ScopeInfo, so we are certain that
// the first constructor scope found in the outer scope chain is the
// scope that we are looking for for this super() call.
// Note that this doesn't necessarily mean that the constructor needs
// a context, if it doesn't this would get handled specially in
// BuildPrivateBrandInitialization().
DeclarationScope* constructor_scope = info()->scope()->GetConstructorScope();
// We can rely on the class_scope_has_private_brand bit to tell if the
// constructor needs private brand initialization, and if that's
// the case we are certain that its outer class scope requires a context to
// keep the brand variable, so we can just get the brand variable
// from the outer scope.
if (constructor_scope->class_scope_has_private_brand()) {
DCHECK(constructor_scope->outer_scope()->is_class_scope());
ClassScope* class_scope = constructor_scope->outer_scope()->AsClassScope();
DCHECK_NOT_NULL(class_scope->brand());
Variable* brand = class_scope->brand();
BuildPrivateBrandInitialization(instance, brand);
}
// The derived constructor has the correct bit set always, so we
// don't emit code to load and call the initializer if not
// required.
//
// For the arrow function or eval case, we always emit code to load
// and call the initializer.
//
// TODO(gsathya): In the future, we could tag nested arrow functions
// or eval with the correct bit so that we do the load conditionally
// if required.
if (info()->literal()->requires_instance_members_initializer() ||
!IsDerivedConstructor(info()->literal()->kind())) {
BuildInstanceMemberInitialization(this_function, instance);
}
}
void BytecodeGenerator::BuildGetAndCheckSuperConstructor(
Register this_function, Register new_target, Register constructor,
BytecodeLabel* super_ctor_call_done) {
bool omit_super_ctor = v8_flags.omit_default_ctors &&
IsDerivedConstructor(info()->literal()->kind());
if (omit_super_ctor) {
BuildSuperCallOptimization(this_function, new_target, constructor,
super_ctor_call_done);
} else {
builder()
->LoadAccumulatorWithRegister(this_function)
.GetSuperConstructor(constructor);
}
// Check if the constructor is in fact a constructor.
builder()->ThrowIfNotSuperConstructor(constructor);
}
void BytecodeGenerator::BuildSuperCallOptimization(
Register this_function, Register new_target,
Register constructor_then_instance, BytecodeLabel* super_ctor_call_done) {
DCHECK(v8_flags.omit_default_ctors);
RegisterList output = register_allocator()->NewRegisterList(2);
builder()->FindNonDefaultConstructorOrConstruct(this_function, new_target,
output);
builder()->MoveRegister(output[1], constructor_then_instance);
builder()->LoadAccumulatorWithRegister(output[0]).JumpIfTrue(
ToBooleanMode::kAlreadyBoolean, super_ctor_call_done);
}
void BytecodeGenerator::VisitCallNew(CallNew* expr) {
RegisterList args = register_allocator()->NewGrowableRegisterList();
// Load the constructor. It's in the first register in args for ease of
// calling %reflect_construct if we have a non-final spread. For all other
// cases it is popped before emitting the construct below.
VisitAndPushIntoRegisterList(expr->expression(), &args);
// We compile the new differently depending on the presence of spreads and
// their positions.
//
// If there is only one spread and it is the final argument, there is a
// special ConstructWithSpread bytecode.
//
// If there is a non-final spread, we rewrite calls like
// new ctor(1, ...x, 2)
// to
// %reflect_construct(ctor, [1, ...x, 2])
const CallNew::SpreadPosition spread_position = expr->spread_position();
if (spread_position == CallNew::kHasNonFinalSpread) {
BuildCreateArrayLiteral(expr->arguments(), nullptr);
builder()->SetExpressionPosition(expr);
builder()
->StoreAccumulatorInRegister(
register_allocator()->GrowRegisterList(&args))
.CallJSRuntime(Context::REFLECT_CONSTRUCT_INDEX, args);
return;
}
Register constructor = args.first_register();
args = args.PopLeft();
VisitArguments(expr->arguments(), &args);
// The accumulator holds new target which is the same as the
// constructor for CallNew.
builder()->SetExpressionPosition(expr);
builder()->LoadAccumulatorWithRegister(constructor);
int feedback_slot_index = feedback_index(feedback_spec()->AddCallICSlot());
if (spread_position == CallNew::kHasFinalSpread) {
builder()->ConstructWithSpread(constructor, args, feedback_slot_index);
} else {
DCHECK_EQ(spread_position, CallNew::kNoSpread);
builder()->Construct(constructor, args, feedback_slot_index);
}
}
void BytecodeGenerator::VisitSuperCallForwardArgs(SuperCallForwardArgs* expr) {
RegisterAllocationScope register_scope(this);
SuperCallReference* super = expr->expression();
Register this_function = VisitForRegisterValue(super->this_function_var());
Register new_target = VisitForRegisterValue(super->new_target_var());
// This register initially holds the constructor, then the instance.
Register constructor_then_instance = register_allocator()->NewRegister();
BytecodeLabel super_ctor_call_done;
{
const Register& constructor = constructor_then_instance;
BuildGetAndCheckSuperConstructor(this_function, new_target, constructor,
&super_ctor_call_done);
builder()->LoadAccumulatorWithRegister(new_target);
builder()->SetExpressionPosition(expr);
int feedback_slot_index = feedback_index(feedback_spec()->AddCallICSlot());
builder()->ConstructForwardAllArgs(constructor, feedback_slot_index);
}
// From here onwards, constructor_then_instance holds the instance.
const Register& instance = constructor_then_instance;
builder()->StoreAccumulatorInRegister(instance);
builder()->Bind(&super_ctor_call_done);
BuildInstanceInitializationAfterSuperCall(this_function, instance);
builder()->LoadAccumulatorWithRegister(instance);
}
void BytecodeGenerator::VisitCallRuntime(CallRuntime* expr) {
// Evaluate all arguments to the runtime call.
RegisterList args = register_allocator()->NewGrowableRegisterList();
VisitArguments(expr->arguments(), &args);
Runtime::FunctionId function_id = expr->function()->function_id;
builder()->CallRuntime(function_id, args);
}
void BytecodeGenerator::VisitVoid(UnaryOperation* expr) {
VisitForEffect(expr->expression());
builder()->LoadUndefined();
}
void BytecodeGenerator::VisitForTypeOfValue(Expression* expr) {
if (expr->IsVariableProxy()) {
// Typeof does not throw a reference error on global variables, hence we
// perform a non-contextual load in case the operand is a variable proxy.
VariableProxy* proxy = expr->AsVariableProxy();
BuildVariableLoadForAccumulatorValue(proxy->var(), proxy->hole_check_mode(),
TypeofMode::kInside);
} else {
VisitForAccumulatorValue(expr);
}
}
void BytecodeGenerator::VisitTypeOf(UnaryOperation* expr) {
VisitForTypeOfValue(expr->expression());
builder()->TypeOf(feedback_index(feedback_spec()->AddTypeOfSlot()));
execution_result()->SetResultIsInternalizedString();
}
void BytecodeGenerator::VisitNot(UnaryOperation* expr) {
if (execution_result()->IsEffect()) {
VisitForEffect(expr->expression());
} else if (execution_result()->IsTest()) {
// No actual logical negation happening, we just swap the control flow, by
// swapping the target labels and the fallthrough branch, and visit in the
// same test result context.
TestResultScope* test_result = execution_result()->AsTest();
test_result->InvertControlFlow();
VisitInSameTestExecutionScope(expr->expression());
} else {
UnaryOperation* unary_op = expr->expression()->AsUnaryOperation();
if (unary_op && unary_op->op() == Token::kNot) {
// Shortcut repeated nots, to capture the `!!foo` pattern for converting
// expressions to booleans.
TypeHint type_hint = VisitForAccumulatorValue(unary_op->expression());
builder()->ToBoolean(ToBooleanModeFromTypeHint(type_hint));
} else {
TypeHint type_hint = VisitForAccumulatorValue(expr->expression());
builder()->LogicalNot(ToBooleanModeFromTypeHint(type_hint));
}
// Always returns a boolean value.
execution_result()->SetResultIsBoolean();
}
}
void BytecodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
switch (expr->op()) {
case Token::kNot:
VisitNot(expr);
break;
case Token::kTypeOf:
VisitTypeOf(expr);
break;
case Token::kVoid:
VisitVoid(expr);
break;
case Token::kDelete:
VisitDelete(expr);
break;
case Token::kAdd:
case Token::kSub:
case Token::kBitNot:
VisitForAccumulatorValue(expr->expression());
builder()->SetExpressionPosition(expr);
builder()->UnaryOperation(
expr->op(), feedback_index(feedback_spec()->AddBinaryOpICSlot()));
break;
default:
UNREACHABLE();
}
}
void BytecodeGenerator::VisitDelete(UnaryOperation* unary) {
Expression* expr = unary->expression();
if (expr->IsProperty()) {
// Delete of an object property is allowed both in sloppy
// and strict modes.
Property* property = expr->AsProperty();
DCHECK(!property->IsPrivateReference());
if (property->IsSuperAccess()) {
// Delete of super access is not allowed.
VisitForEffect(property->key());
builder()->CallRuntime(Runtime::kThrowUnsupportedSuperError);
} else {
Register object = VisitForRegisterValue(property->obj());
VisitForAccumulatorValue(property->key());
builder()->Delete(object, language_mode());
}
} else if (expr->IsOptionalChain()) {
Expression* expr_inner = expr->AsOptionalChain()->expression();
if (expr_inner->IsProperty()) {
Property* property = expr_inner->AsProperty();
DCHECK(!property->IsPrivateReference());
BytecodeLabel done;
OptionalChainNullLabelScope label_scope(this);
VisitForAccumulatorValue(property->obj());
if (property->is_optional_chain_link()) {
int right_range = AllocateBlockCoverageSlotIfEnabled(
property, SourceRangeKind::kRight);
builder()->JumpIfUndefinedOrNull(label_scope.labels()->New());
BuildIncrementBlockCoverageCounterIfEnabled(right_range);
}
Register object = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(object);
if (property->is_optional_chain_link()) {
VisitInHoleCheckElisionScopeForAccumulatorValue(property->key());
} else {
VisitForAccumulatorValue(property->key());
}
builder()->Delete(object, language_mode());
builder()->Jump(&done);
label_scope.labels()->Bind(builder());
builder()->LoadTrue();
builder()->Bind(&done);
} else {
VisitForEffect(expr);
builder()->LoadTrue();
}
} else if (expr->IsVariableProxy() &&
!expr->AsVariableProxy()->is_new_target()) {
// Delete of an unqualified identifier is allowed in sloppy mode but is
// not allowed in strict mode.
DCHECK(is_sloppy(language_mode()));
Variable* variable = expr->AsVariableProxy()->var();
switch (variable->location()) {
case VariableLocation::PARAMETER:
case VariableLocation::LOCAL:
case VariableLocation::CONTEXT:
case VariableLocation::REPL_GLOBAL: {
// Deleting local var/let/const, context variables, and arguments
// does not have any effect.
builder()->LoadFalse();
break;
}
case VariableLocation::UNALLOCATED:
// TODO(adamk): Falling through to the runtime results in correct
// behavior, but does unnecessary context-walking (since scope
// analysis has already proven that the variable doesn't exist in
// any non-global scope). Consider adding a DeleteGlobal bytecode
// that knows how to deal with ScriptContexts as well as global
// object properties.
case VariableLocation::LOOKUP: {
Register name_reg = register_allocator()->NewRegister();
builder()
->LoadLiteral(variable->raw_name())
.StoreAccumulatorInRegister(name_reg)
.CallRuntime(Runtime::kDeleteLookupSlot, name_reg);
break;
}
case VariableLocation::MODULE:
// Modules are always in strict mode and unqualified identifiers are not
// allowed in strict mode.
UNREACHABLE();
}
} else {
// Delete of an unresolvable reference, new.target, and this returns true.
VisitForEffect(expr);
builder()->LoadTrue();
}
}
void BytecodeGenerator::VisitCountOperation(CountOperation* expr) {
DCHECK(expr->expression()->IsValidReferenceExpression());
// Left-hand side can only be a property, a global or a variable slot.
Property* property = expr->expression()->AsProperty();
AssignType assign_type = Property::GetAssignType(property);
bool is_postfix = expr->is_postfix() && !execution_result()->IsEffect();
// Evaluate LHS expression and get old value.
Register object, key, old_value;
RegisterList super_property_args;
const AstRawString* name;
switch (assign_type) {
case NON_PROPERTY: {
VariableProxy* proxy = expr->expression()->AsVariableProxy();
BuildVariableLoadForAccumulatorValue(proxy->var(),
proxy->hole_check_mode());
break;
}
case NAMED_PROPERTY: {
object = VisitForRegisterValue(property->obj());
name = property->key()->AsLiteral()->AsRawPropertyName();
builder()->LoadNamedProperty(
object, name,
feedback_index(GetCachedLoadICSlot(property->obj(), name)));
break;
}
case KEYED_PROPERTY: {
object = VisitForRegisterValue(property->obj());
// Use visit for accumulator here since we need the key in the accumulator
// for the LoadKeyedProperty.
key = register_allocator()->NewRegister();
VisitForAccumulatorValue(property->key());
builder()->StoreAccumulatorInRegister(key).LoadKeyedProperty(
object, feedback_index(feedback_spec()->AddKeyedLoadICSlot()));
break;
}
case NAMED_SUPER_PROPERTY: {
super_property_args = register_allocator()->NewRegisterList(4);
RegisterList load_super_args = super_property_args.Truncate(3);
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(load_super_args[0]);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(load_super_args[1]);
builder()
->LoadLiteral(property->key()->AsLiteral()->AsRawPropertyName())
.StoreAccumulatorInRegister(load_super_args[2])
.CallRuntime(Runtime::kLoadFromSuper, load_super_args);
break;
}
case KEYED_SUPER_PROPERTY: {
super_property_args = register_allocator()->NewRegisterList(4);
RegisterList load_super_args = super_property_args.Truncate(3);
BuildThisVariableLoad();
builder()->StoreAccumulatorInRegister(load_super_args[0]);
BuildVariableLoad(
property->obj()->AsSuperPropertyReference()->home_object()->var(),
HoleCheckMode::kElided);
builder()->StoreAccumulatorInRegister(load_super_args[1]);
VisitForRegisterValue(property->key(), load_super_args[2]);
builder()->CallRuntime(Runtime::kLoadKeyedFromSuper, load_super_args);
break;
}
case PRIVATE_METHOD: {
object = VisitForRegisterValue(property->obj());
BuildPrivateBrandCheck(property, object);
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateMethodWrite,
property);
return;
}
case PRIVATE_GETTER_ONLY: {
object = VisitForRegisterValue(property->obj());
BuildPrivateBrandCheck(property, object);
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateSetterAccess,
property);
return;
}
case PRIVATE_SETTER_ONLY: {
object = VisitForRegisterValue(property->obj());
BuildPrivateBrandCheck(property, object);
BuildInvalidPropertyAccess(MessageTemplate::kInvalidPrivateGetterAccess,
property);
return;
}
case PRIVATE_GETTER_AND_SETTER: {
object = VisitForRegisterValue(property->obj());
key = VisitForRegisterValue(property->key());
BuildPrivateBrandCheck(property, object);
BuildPrivateGetterAccess(object, key);
break;
}
case PRIVATE_DEBUG_DYNAMIC: {
object = VisitForRegisterValue(property->obj());
BuildPrivateDebugDynamicGet(property, object);
break;
}
}
// Save result for postfix expressions.
FeedbackSlot count_slot = feedback_spec()->AddBinaryOpICSlot();
if (is_postfix) {
old_value = register_allocator()->NewRegister();
// Convert old value into a number before saving it.
// TODO(ignition): Think about adding proper PostInc/PostDec bytecodes
// instead of this ToNumeric + Inc/Dec dance.
builder()
->ToNumeric(feedback_index(count_slot))
.StoreAccumulatorInRegister(old_value);
}
// Perform +1/-1 operation.
builder()->UnaryOperation(expr->op(), feedback_index(count_slot));
// Store the value.
builder()->SetExpressionPosition(expr);
switch (assign_type) {
case NON_PROPERTY: {
VariableProxy* proxy = expr->expression()->AsVariableProxy();
BuildVariableAssignment(proxy->var(), expr->op(),
proxy->hole_check_mode());
break;
}
case NAMED_PROPERTY: {
FeedbackSlot slot = GetCachedStoreICSlot(property->obj(), name);
Register value;
if (!execution_result()->IsEffect()) {
value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
}
builder()->SetNamedProperty(object, name, feedback_index(slot),
language_mode());
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
break;
}
case KEYED_PROPERTY: {
FeedbackSlot slot = feedback_spec()->AddKeyedStoreICSlot(language_mode());
Register value;
if (!execution_result()->IsEffect()) {
value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
}
builder()->SetKeyedProperty(object, key, feedback_index(slot),
language_mode());
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
break;
}
case NAMED_SUPER_PROPERTY: {
builder()
->StoreAccumulatorInRegister(super_property_args[3])
.CallRuntime(Runtime::kStoreToSuper, super_property_args);
break;
}
case KEYED_SUPER_PROPERTY: {
builder()
->StoreAccumulatorInRegister(super_property_args[3])
.CallRuntime(Runtime::kStoreKeyedToSuper, super_property_args);
break;
}
case PRIVATE_SETTER_ONLY:
case PRIVATE_GETTER_ONLY:
case PRIVATE_METHOD: {
UNREACHABLE();
}
case PRIVATE_GETTER_AND_SETTER: {
Register value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
BuildPrivateSetterAccess(object, key, value);
if (!execution_result()->IsEffect()) {
builder()->LoadAccumulatorWithRegister(value);
}
break;
}
case PRIVATE_DEBUG_DYNAMIC: {
Register value = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(value);
BuildPrivateDebugDynamicSet(property, object, value);
break;
}
}
// Restore old value for postfix expressions.
if (is_postfix) {
builder()->LoadAccumulatorWithRegister(old_value);
}
}
void BytecodeGenerator::VisitBinaryOperation(BinaryOperation* binop) {
switch (binop->op()) {
case Token::kComma:
VisitCommaExpression(binop);
break;
case Token::kOr:
VisitLogicalOrExpression(binop);
break;
case Token::kAnd:
VisitLogicalAndExpression(binop);
break;
case Token::kNullish:
VisitNullishExpression(binop);
break;
default:
VisitArithmeticExpression(binop);
break;
}
}
void BytecodeGenerator::VisitNaryOperation(NaryOperation* expr) {
switch (expr->op()) {
case Token::kComma:
VisitNaryCommaExpression(expr);
break;
case Token::kOr:
VisitNaryLogicalOrExpression(expr);
break;
case Token::kAnd:
VisitNaryLogicalAndExpression(expr);
break;
case Token::kNullish:
VisitNaryNullishExpression(expr);
break;
default:
VisitNaryArithmeticExpression(expr);
break;
}
}
void BytecodeGenerator::BuildLiteralCompareNil(
Token::Value op, BytecodeArrayBuilder::NilValue nil) {
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
switch (test_result->fallthrough()) {
case TestFallthrough::kThen:
builder()->JumpIfNotNil(test_result->NewElseLabel(), op, nil);
break;
case TestFallthrough::kElse:
builder()->JumpIfNil(test_result->NewThenLabel(), op, nil);
break;
case TestFallthrough::kNone:
builder()
->JumpIfNil(test_result->NewThenLabel(), op, nil)
.Jump(test_result->NewElseLabel());
}
test_result->SetResultConsumedByTest();
} else {
builder()->CompareNil(op, nil);
}
}
void BytecodeGenerator::BuildLiteralStrictCompareBoolean(Literal* literal) {
DCHECK(literal->IsBooleanLiteral());
Register result = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(result);
builder()->LoadBoolean(literal->AsBooleanLiteral());
builder()->CompareReference(result);
}
bool BytecodeGenerator::IsLocalVariableWithInternalizedStringHint(
Expression* expr) {
VariableProxy* proxy = expr->AsVariableProxy();
return proxy != nullptr && proxy->is_resolved() &&
proxy->var()->IsStackLocal() &&
GetTypeHintForLocalVariable(proxy->var()) ==
TypeHint::kInternalizedString;
}
static bool IsTypeof(Expression* expr) {
UnaryOperation* maybe_unary = expr->AsUnaryOperation();
return maybe_unary != nullptr && maybe_unary->op() == Token::kTypeOf;
}
static bool IsCharU(const AstRawString* str) {
return str->length() == 1 && str->FirstCharacter() == 'u';
}
static bool IsLiteralCompareTypeof(CompareOperation* expr,
Expression** sub_expr,
TestTypeOfFlags::LiteralFlag* flag,
const AstStringConstants* ast_constants) {
if (IsTypeof(expr->left()) && expr->right()->IsStringLiteral()) {
Literal* right_lit = expr->right()->AsLiteral();
if (Token::IsEqualityOp(expr->op())) {
// typeof(x) === 'string'
*flag = TestTypeOfFlags::GetFlagForLiteral(ast_constants, right_lit);
} else if (expr->op() == Token::kGreaterThan &&
IsCharU(right_lit->AsRawString())) {
// typeof(x) > 'u'
// Minifier may convert `typeof(x) === 'undefined'` to this form,
// since `undefined` is the only valid value that is greater than 'u'.
// Check the test OnlyUndefinedGreaterThanU in bytecodes-unittest.cc
*flag = TestTypeOfFlags::LiteralFlag::kUndefined;
} else {
return false;
}
*sub_expr = expr->left()->AsUnaryOperation()->expression();
return true;
}
if (IsTypeof(expr->right()) && expr->left()->IsStringLiteral()) {
Literal* left_lit = expr->left()->AsLiteral();
if (Token::IsEqualityOp(expr->op())) {
// 'string' === typeof(x)
*flag = TestTypeOfFlags::GetFlagForLiteral(ast_constants, left_lit);
} else if (expr->op() == Token::kLessThan &&
IsCharU(left_lit->AsRawString())) {
// 'u' < typeof(x)
*flag = TestTypeOfFlags::LiteralFlag::kUndefined;
} else {
return false;
}
*sub_expr = expr->right()->AsUnaryOperation()->expression();
return true;
}
return false;
}
void BytecodeGenerator::VisitCompareOperation(CompareOperation* expr) {
Expression* sub_expr;
Literal* literal;
TestTypeOfFlags::LiteralFlag flag;
if (IsLiteralCompareTypeof(expr, &sub_expr, &flag, ast_string_constants())) {
// Emit a fast literal comparison for expressions of the form:
// typeof(x) === 'string'.
VisitForTypeOfValue(sub_expr);
builder()->SetExpressionPosition(expr);
if (flag == TestTypeOfFlags::LiteralFlag::kOther) {
builder()->LoadFalse();
} else {
builder()->CompareTypeOf(flag);
}
} else if (expr->IsLiteralStrictCompareBoolean(&sub_expr, &literal)) {
DCHECK(expr->op() == Token::kEqStrict);
VisitForAccumulatorValue(sub_expr);
builder()->SetExpressionPosition(expr);
BuildLiteralStrictCompareBoolean(literal);
} else if (expr->IsLiteralCompareUndefined(&sub_expr)) {
VisitForAccumulatorValue(sub_expr);
builder()->SetExpressionPosition(expr);
BuildLiteralCompareNil(expr->op(), BytecodeArrayBuilder::kUndefinedValue);
} else if (expr->IsLiteralCompareNull(&sub_expr)) {
VisitForAccumulatorValue(sub_expr);
builder()->SetExpressionPosition(expr);
BuildLiteralCompareNil(expr->op(), BytecodeArrayBuilder::kNullValue);
} else if (expr->IsLiteralCompareEqualVariable(&sub_expr, &literal) &&
IsLocalVariableWithInternalizedStringHint(sub_expr)) {
builder()->LoadLiteral(literal->AsRawString());
builder()->CompareReference(
GetRegisterForLocalVariable(sub_expr->AsVariableProxy()->var()));
} else {
if (expr->op() == Token::kIn && expr->left()->IsPrivateName()) {
Variable* var = expr->left()->AsVariableProxy()->var();
if (IsPrivateMethodOrAccessorVariableMode(var->mode())) {
BuildPrivateMethodIn(var, expr->right());
return;
}
// For private fields, the code below does the right thing.
}
Register lhs = VisitForRegisterValue(expr->left());
VisitForAccumulatorValue(expr->right());
builder()->SetExpressionPosition(expr);
FeedbackSlot slot;
if (expr->op() == Token::kIn) {
slot = feedback_spec()->AddKeyedHasICSlot();
} else if (expr->op() == Token::kInstanceOf) {
slot = feedback_spec()->AddInstanceOfSlot();
} else {
slot = feedback_spec()->AddCompareICSlot();
}
builder()->CompareOperation(expr->op(), lhs, feedback_index(slot));
}
// Always returns a boolean value.
execution_result()->SetResultIsBoolean();
}
void BytecodeGenerator::VisitArithmeticExpression(BinaryOperation* expr) {
FeedbackSlot slot;
// We special-case string concatenation when the result is used as a property
// key. In this case, we know it will eventually be internalized and it's
// better to do so early.
//
// For now, we handle only the specialized situation in which lhs is a string
// constant.
// TODO(jgruber): Generalize. ConsString literals, rhs-as-literal,
// property-key but no string-literal, string-literal but no property-key.
const bool emit_add_lhs_is_string_constant_internalize =
expr->op() == Token::kAdd && execution_result()->IsValueAsPropertyKey() &&
expr->left()->IsLiteral() && expr->left()->AsLiteral()->IsRawString() &&
v8_flags.cache_property_key_string_adds;
if (emit_add_lhs_is_string_constant_internalize) {
slot = feedback_spec()->AddStringAddAndInternalizeICSlot();
} else {
slot = feedback_spec()->AddBinaryOpICSlot();
}
Expression* subexpr;
Tagged<Smi> literal;
if (expr->IsSmiLiteralOperation(&subexpr, &literal)) {
TypeHint type_hint = VisitForAccumulatorValue(subexpr);
builder()->SetExpressionPosition(expr);
builder()->BinaryOperationSmiLiteral(expr->op(), literal,
feedback_index(slot));
if (expr->op() == Token::kAdd && IsStringTypeHint(type_hint)) {
execution_result()->SetResultIsString();
}
} else {
TypeHint lhs_type = VisitForAccumulatorValue(expr->left());
Register lhs = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(lhs);
TypeHint rhs_type = VisitForAccumulatorValue(expr->right());
if (expr->op() == Token::kAdd &&
(IsStringTypeHint(lhs_type) || IsStringTypeHint(rhs_type))) {
execution_result()->SetResultIsString();
}
if (emit_add_lhs_is_string_constant_internalize) {
DCHECK(IsStringTypeHint(lhs_type));
builder()->SetExpressionPosition(expr);
builder()->Add_LhsIsStringConstant_Internalize(expr->op(), lhs,
feedback_index(slot));
} else {
builder()->SetExpressionPosition(expr);
builder()->BinaryOperation(expr->op(), lhs, feedback_index(slot));
}
}
}
void BytecodeGenerator::VisitNaryArithmeticExpression(NaryOperation* expr) {
// TODO(leszeks): Add support for lhs smi in commutative ops.
TypeHint type_hint = VisitForAccumulatorValue(expr->first());
for (size_t i = 0; i < expr->subsequent_length(); ++i) {
RegisterAllocationScope register_scope(this);
if (expr->subsequent(i)->IsSmiLiteral()) {
builder()->SetExpressionPosition(expr->subsequent_op_position(i));
builder()->BinaryOperationSmiLiteral(
expr->op(), expr->subsequent(i)->AsLiteral()->AsSmiLiteral(),
feedback_index(feedback_spec()->AddBinaryOpICSlot()));
} else {
Register lhs = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(lhs);
TypeHint rhs_hint = VisitForAccumulatorValue(expr->subsequent(i));
if (IsStringTypeHint(rhs_hint)) type_hint = TypeHint::kString;
builder()->SetExpressionPosition(expr->subsequent_op_position(i));
builder()->BinaryOperation(
expr->op(), lhs,
feedback_index(feedback_spec()->AddBinaryOpICSlot()));
}
}
if (IsStringTypeHint(type_hint) && expr->op() == Token::kAdd) {
// If any operand of an ADD is a String, a String is produced.
execution_result()->SetResultIsString();
}
}
// Note: the actual spreading is performed by the surrounding expression's
// visitor.
void BytecodeGenerator::VisitSpread(Spread* expr) { Visit(expr->expression()); }
void BytecodeGenerator::VisitEmptyParentheses(EmptyParentheses* expr) {
UNREACHABLE();
}
void BytecodeGenerator::VisitImportCallExpression(ImportCallExpression* expr) {
const int register_count = expr->import_options() ? 4 : 3;
// args is a list of [ function_closure, specifier, phase, import_options ].
RegisterList args = register_allocator()->NewRegisterList(register_count);
builder()->MoveRegister(Register::function_closure(), args[0]);
VisitForRegisterValue(expr->specifier(), args[1]);
builder()
->LoadLiteral(Smi::FromInt(static_cast<int>(expr->phase())))
.StoreAccumulatorInRegister(args[2]);
if (expr->import_options()) {
VisitForRegisterValue(expr->import_options(), args[3]);
}
builder()->CallRuntime(Runtime::kDynamicImportCall, args);
}
void BytecodeGenerator::BuildGetIterator(IteratorType hint) {
if (hint == IteratorType::kAsync) {
RegisterAllocationScope scope(this);
Register obj = register_allocator()->NewRegister();
Register method = register_allocator()->NewRegister();
// Set method to GetMethod(obj, @@asyncIterator)
builder()->StoreAccumulatorInRegister(obj).LoadAsyncIteratorProperty(
obj, feedback_index(feedback_spec()->AddLoadICSlot()));
BytecodeLabel async_iterator_undefined, done;
builder()->JumpIfUndefinedOrNull(&async_iterator_undefined);
// Let iterator be Call(method, obj)
builder()->StoreAccumulatorInRegister(method).CallProperty(
method, RegisterList(obj),
feedback_index(feedback_spec()->AddCallICSlot()));
// If Type(iterator) is not Object, throw a TypeError exception.
builder()->JumpIfJSReceiver(&done);
builder()->CallRuntime(Runtime::kThrowSymbolAsyncIteratorInvalid);
builder()->Bind(&async_iterator_undefined);
// If method is undefined,
// Let syncMethod be GetMethod(obj, @@iterator)
builder()
->LoadIteratorProperty(obj,
feedback_index(feedback_spec()->AddLoadICSlot()))
.StoreAccumulatorInRegister(method);
// Let syncIterator be Call(syncMethod, obj)
builder()->CallProperty(method, RegisterList(obj),
feedback_index(feedback_spec()->AddCallICSlot()));
// Return CreateAsyncFromSyncIterator(syncIterator)
// alias `method` register as it's no longer used
Register sync_iter = method;
builder()->StoreAccumulatorInRegister(sync_iter).CallRuntime(
Runtime::kInlineCreateAsyncFromSyncIterator, sync_iter);
builder()->Bind(&done);
} else {
{
RegisterAllocationScope scope(this);
Register obj = register_allocator()->NewRegister();
int load_feedback_index =
feedback_index(feedback_spec()->AddLoadICSlot());
int call_feedback_index =
feedback_index(feedback_spec()->AddCallICSlot());
// Let method be GetMethod(obj, @@iterator) and
// iterator be Call(method, obj). If iterator is
// not JSReceiver, then throw TypeError.
builder()->StoreAccumulatorInRegister(obj).GetIterator(
obj, load_feedback_index, call_feedback_index);
}
}
}
// Returns an IteratorRecord which is valid for the lifetime of the current
// register_allocation_scope.
BytecodeGenerator::IteratorRecord BytecodeGenerator::BuildGetIteratorRecord(
Register next, Register object, IteratorType hint) {
DCHECK(next.is_valid() && object.is_valid());
BuildGetIterator(hint);
builder()
->StoreAccumulatorInRegister(object)
.LoadNamedProperty(object, ast_string_constants()->next_string(),
feedback_index(feedback_spec()->AddLoadICSlot()))
.StoreAccumulatorInRegister(next);
return IteratorRecord(object, next, hint);
}
BytecodeGenerator::IteratorRecord BytecodeGenerator::BuildGetIteratorRecord(
IteratorType hint) {
Register next = register_allocator()->NewRegister();
Register object = register_allocator()->NewRegister();
return BuildGetIteratorRecord(next, object, hint);
}
void BytecodeGenerator::BuildIteratorNext(const IteratorRecord& iterator,
Register next_result) {
DCHECK(next_result.is_valid());
builder()->CallProperty(iterator.next(), RegisterList(iterator.object()),
feedback_index(feedback_spec()->AddCallICSlot()));
if (iterator.type() == IteratorType::kAsync) {
BuildAwait();
}
BytecodeLabel is_object;
builder()
->StoreAccumulatorInRegister(next_result)
.JumpIfJSReceiver(&is_object)
.CallRuntime(Runtime::kThrowIteratorResultNotAnObject, next_result)
.Bind(&is_object);
}
void BytecodeGenerator::BuildCallIteratorMethod(Register iterator,
const AstRawString* method_name,
RegisterList receiver_and_args,
BytecodeLabel* if_called,
BytecodeLabels* if_notcalled) {
RegisterAllocationScope register_scope(this);
Register method = register_allocator()->NewRegister();
FeedbackSlot slot = feedback_spec()->AddLoadICSlot();
builder()
->LoadNamedProperty(iterator, method_name, feedback_index(slot))
.JumpIfUndefinedOrNull(if_notcalled->New())
.StoreAccumulatorInRegister(method)
.CallProperty(method, receiver_and_args,
feedback_index(feedback_spec()->AddCallICSlot()))
.Jump(if_called);
}
void BytecodeGenerator::BuildIteratorClose(const IteratorRecord& iterator,
Expression* expr) {
RegisterAllocationScope register_scope(this);
BytecodeLabels done(zone());
BytecodeLabel if_called;
RegisterList args = RegisterList(iterator.object());
BuildCallIteratorMethod(iterator.object(),
ast_string_constants()->return_string(), args,
&if_called, &done);
builder()->Bind(&if_called);
if (iterator.type() == IteratorType::kAsync) {
DCHECK_NOT_NULL(expr);
BuildAwait(expr->position());
}
builder()->JumpIfJSReceiver(done.New());
{
RegisterAllocationScope inner_register_scope(this);
Register return_result = register_allocator()->NewRegister();
builder()
->StoreAccumulatorInRegister(return_result)
.CallRuntime(Runtime::kThrowIteratorResultNotAnObject, return_result);
}
done.Bind(builder());
}
void BytecodeGenerator::VisitGetTemplateObject(GetTemplateObject* expr) {
builder()->SetExpressionPosition(expr);
size_t entry = builder()->AllocateDeferredConstantPoolEntry();
template_objects_.push_back(std::make_pair(expr, entry));
FeedbackSlot literal_slot = feedback_spec()->AddLiteralSlot();
builder()->GetTemplateObject(entry, feedback_index(literal_slot));
}
void BytecodeGenerator::VisitTemplateLiteral(TemplateLiteral* expr) {
const ZonePtrList<const AstRawString>& parts = *expr->string_parts();
const ZonePtrList<Expression>& substitutions = *expr->substitutions();
// Template strings with no substitutions are turned into StringLiterals.
DCHECK_GT(substitutions.length(), 0);
DCHECK_EQ(parts.length(), substitutions.length() + 1);
// Generate string concatenation
// TODO(caitp): Don't generate feedback slot if it's not used --- introduce
// a simple, concise, reusable mechanism to lazily create reusable slots.
FeedbackSlot slot = feedback_spec()->AddBinaryOpICSlot();
Register last_part = register_allocator()->NewRegister();
bool last_part_valid = false;
builder()->SetExpressionPosition(expr);
for (int i = 0; i < substitutions.length(); ++i) {
if (i != 0) {
builder()->StoreAccumulatorInRegister(last_part);
last_part_valid = true;
}
if (!parts[i]->IsEmpty()) {
builder()->LoadLiteral(parts[i]);
if (last_part_valid) {
builder()->BinaryOperation(Token::kAdd, last_part,
feedback_index(slot));
}
builder()->StoreAccumulatorInRegister(last_part);
last_part_valid = true;
}
TypeHint type_hint = VisitForAccumulatorValue(substitutions[i]);
if (!IsStringTypeHint(type_hint)) {
builder()->ToString();
}
if (last_part_valid) {
builder()->BinaryOperation(Token::kAdd, last_part, feedback_index(slot));
}
last_part_valid = false;
}
if (!parts.last()->IsEmpty()) {
builder()->StoreAccumulatorInRegister(last_part);
builder()->LoadLiteral(parts.last());
builder()->BinaryOperation(Token::kAdd, last_part, feedback_index(slot));
}
}
void BytecodeGenerator::BuildThisVariableLoad() {
DeclarationScope* receiver_scope = closure_scope()->GetReceiverScope();
Variable* var = receiver_scope->receiver();
// TODO(littledan): implement 'this' hole check elimination.
HoleCheckMode hole_check_mode =
IsDerivedConstructor(receiver_scope->function_kind())
? HoleCheckMode::kRequired
: HoleCheckMode::kElided;
BuildVariableLoad(var, hole_check_mode);
}
void BytecodeGenerator::VisitThisExpression(ThisExpression* expr) {
BuildThisVariableLoad();
}
void BytecodeGenerator::VisitSuperCallReference(SuperCallReference* expr) {
// Handled by VisitCall().
UNREACHABLE();
}
void BytecodeGenerator::VisitSuperPropertyReference(
SuperPropertyReference* expr) {
// Handled by VisitAssignment(), VisitCall(), VisitDelete() and
// VisitPropertyLoad().
UNREACHABLE();
}
void BytecodeGenerator::VisitCommaExpression(BinaryOperation* binop) {
VisitForEffect(binop->left());
builder()->SetExpressionAsStatementPosition(binop->right());
Visit(binop->right());
}
void BytecodeGenerator::VisitNaryCommaExpression(NaryOperation* expr) {
DCHECK_GT(expr->subsequent_length(), 0);
VisitForEffect(expr->first());
for (size_t i = 0; i < expr->subsequent_length() - 1; ++i) {
builder()->SetExpressionAsStatementPosition(expr->subsequent(i));
VisitForEffect(expr->subsequent(i));
}
builder()->SetExpressionAsStatementPosition(
expr->subsequent(expr->subsequent_length() - 1));
Visit(expr->subsequent(expr->subsequent_length() - 1));
}
void BytecodeGenerator::VisitLogicalTestSubExpression(
Token::Value token, Expression* expr, BytecodeLabels* then_labels,
BytecodeLabels* else_labels, int coverage_slot) {
DCHECK(token == Token::kOr || token == Token::kAnd ||
token == Token::kNullish);
BytecodeLabels test_next(zone());
if (token == Token::kOr) {
VisitForTest(expr, then_labels, &test_next, TestFallthrough::kElse);
} else if (token == Token::kAnd) {
VisitForTest(expr, &test_next, else_labels, TestFallthrough::kThen);
} else {
DCHECK_EQ(Token::kNullish, token);
VisitForNullishTest(expr, then_labels, &test_next, else_labels);
}
test_next.Bind(builder());
BuildIncrementBlockCoverageCounterIfEnabled(coverage_slot);
}
void BytecodeGenerator::VisitLogicalTest(Token::Value token, Expression* left,
Expression* right,
int right_coverage_slot) {
DCHECK(token == Token::kOr || token == Token::kAnd ||
token == Token::kNullish);
TestResultScope* test_result = execution_result()->AsTest();
BytecodeLabels* then_labels = test_result->then_labels();
BytecodeLabels* else_labels = test_result->else_labels();
TestFallthrough fallthrough = test_result->fallthrough();
VisitLogicalTestSubExpression(token, left, then_labels, else_labels,
right_coverage_slot);
// The last test has the same then, else and fallthrough as the parent test.
HoleCheckElisionScope elider(this);
VisitForTest(right, then_labels, else_labels, fallthrough);
}
void BytecodeGenerator::VisitNaryLogicalTest(
Token::Value token, NaryOperation* expr,
const NaryCodeCoverageSlots* coverage_slots) {
DCHECK(token == Token::kOr || token == Token::kAnd ||
token == Token::kNullish);
DCHECK_GT(expr->subsequent_length(), 0);
TestResultScope* test_result = execution_result()->AsTest();
BytecodeLabels* then_labels = test_result->then_labels();
BytecodeLabels* else_labels = test_result->else_labels();
TestFallthrough fallthrough = test_result->fallthrough();
VisitLogicalTestSubExpression(token, expr->first(), then_labels, else_labels,
coverage_slots->GetSlotFor(0));
HoleCheckElisionScope elider(this);
for (size_t i = 0; i < expr->subsequent_length() - 1; ++i) {
VisitLogicalTestSubExpression(token, expr->subsequent(i), then_labels,
else_labels,
coverage_slots->GetSlotFor(i + 1));
}
// The last test has the same then, else and fallthrough as the parent test.
VisitForTest(expr->subsequent(expr->subsequent_length() - 1), then_labels,
else_labels, fallthrough);
}
bool BytecodeGenerator::VisitLogicalOrSubExpression(Expression* expr,
BytecodeLabels* end_labels,
int coverage_slot) {
if (expr->ToBooleanIsTrue()) {
VisitForAccumulatorValue(expr);
end_labels->Bind(builder());
return true;
} else if (!expr->ToBooleanIsFalse()) {
TypeHint type_hint = VisitForAccumulatorValue(expr);
builder()->JumpIfTrue(ToBooleanModeFromTypeHint(type_hint),
end_labels->New());
}
BuildIncrementBlockCoverageCounterIfEnabled(coverage_slot);
return false;
}
bool BytecodeGenerator::VisitLogicalAndSubExpression(Expression* expr,
BytecodeLabels* end_labels,
int coverage_slot) {
if (expr->ToBooleanIsFalse()) {
VisitForAccumulatorValue(expr);
end_labels->Bind(builder());
return true;
} else if (!expr->ToBooleanIsTrue()) {
TypeHint type_hint = VisitForAccumulatorValue(expr);
builder()->JumpIfFalse(ToBooleanModeFromTypeHint(type_hint),
end_labels->New());
}
BuildIncrementBlockCoverageCounterIfEnabled(coverage_slot);
return false;
}
bool BytecodeGenerator::VisitNullishSubExpression(Expression* expr,
BytecodeLabels* end_labels,
int coverage_slot) {
if (expr->IsLiteralButNotNullOrUndefined()) {
VisitForAccumulatorValue(expr);
end_labels->Bind(builder());
return true;
} else if (!expr->IsNullOrUndefinedLiteral()) {
VisitForAccumulatorValue(expr);
BytecodeLabel is_null_or_undefined;
builder()
->JumpIfUndefinedOrNull(&is_null_or_undefined)
.Jump(end_labels->New());
builder()->Bind(&is_null_or_undefined);
}
BuildIncrementBlockCoverageCounterIfEnabled(coverage_slot);
return false;
}
void BytecodeGenerator::VisitLogicalOrExpression(BinaryOperation* binop) {
Expression* left = binop->left();
Expression* right = binop->right();
int right_coverage_slot =
AllocateBlockCoverageSlotIfEnabled(binop, SourceRangeKind::kRight);
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
if (left->ToBooleanIsTrue()) {
builder()->Jump(test_result->NewThenLabel());
} else if (left->ToBooleanIsFalse() && right->ToBooleanIsFalse()) {
BuildIncrementBlockCoverageCounterIfEnabled(right_coverage_slot);
builder()->Jump(test_result->NewElseLabel());
} else {
VisitLogicalTest(Token::kOr, left, right, right_coverage_slot);
}
test_result->SetResultConsumedByTest();
} else {
BytecodeLabels end_labels(zone());
if (VisitLogicalOrSubExpression(left, &end_labels, right_coverage_slot)) {
return;
}
VisitInHoleCheckElisionScopeForAccumulatorValue(right);
end_labels.Bind(builder());
}
}
void BytecodeGenerator::VisitNaryLogicalOrExpression(NaryOperation* expr) {
Expression* first = expr->first();
DCHECK_GT(expr->subsequent_length(), 0);
NaryCodeCoverageSlots coverage_slots(this, expr);
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
if (first->ToBooleanIsTrue()) {
builder()->Jump(test_result->NewThenLabel());
} else {
VisitNaryLogicalTest(Token::kOr, expr, &coverage_slots);
}
test_result->SetResultConsumedByTest();
} else {
BytecodeLabels end_labels(zone());
if (VisitLogicalOrSubExpression(first, &end_labels,
coverage_slots.GetSlotFor(0))) {
return;
}
HoleCheckElisionScope elider(this);
for (size_t i = 0; i < expr->subsequent_length() - 1; ++i) {
if (VisitLogicalOrSubExpression(expr->subsequent(i), &end_labels,
coverage_slots.GetSlotFor(i + 1))) {
return;
}
}
// We have to visit the last value even if it's true, because we need its
// actual value.
VisitForAccumulatorValue(expr->subsequent(expr->subsequent_length() - 1));
end_labels.Bind(builder());
}
}
void BytecodeGenerator::VisitLogicalAndExpression(BinaryOperation* binop) {
Expression* left = binop->left();
Expression* right = binop->right();
int right_coverage_slot =
AllocateBlockCoverageSlotIfEnabled(binop, SourceRangeKind::kRight);
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
if (left->ToBooleanIsFalse()) {
builder()->Jump(test_result->NewElseLabel());
} else if (left->ToBooleanIsTrue() && right->ToBooleanIsTrue()) {
BuildIncrementBlockCoverageCounterIfEnabled(right_coverage_slot);
builder()->Jump(test_result->NewThenLabel());
} else {
VisitLogicalTest(Token::kAnd, left, right, right_coverage_slot);
}
test_result->SetResultConsumedByTest();
} else {
BytecodeLabels end_labels(zone());
if (VisitLogicalAndSubExpression(left, &end_labels, right_coverage_slot)) {
return;
}
VisitInHoleCheckElisionScopeForAccumulatorValue(right);
end_labels.Bind(builder());
}
}
void BytecodeGenerator::VisitNaryLogicalAndExpression(NaryOperation* expr) {
Expression* first = expr->first();
DCHECK_GT(expr->subsequent_length(), 0);
NaryCodeCoverageSlots coverage_slots(this, expr);
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
if (first->ToBooleanIsFalse()) {
builder()->Jump(test_result->NewElseLabel());
} else {
VisitNaryLogicalTest(Token::kAnd, expr, &coverage_slots);
}
test_result->SetResultConsumedByTest();
} else {
BytecodeLabels end_labels(zone());
if (VisitLogicalAndSubExpression(first, &end_labels,
coverage_slots.GetSlotFor(0))) {
return;
}
HoleCheckElisionScope elider(this);
for (size_t i = 0; i < expr->subsequent_length() - 1; ++i) {
if (VisitLogicalAndSubExpression(expr->subsequent(i), &end_labels,
coverage_slots.GetSlotFor(i + 1))) {
return;
}
}
// We have to visit the last value even if it's false, because we need its
// actual value.
VisitForAccumulatorValue(expr->subsequent(expr->subsequent_length() - 1));
end_labels.Bind(builder());
}
}
void BytecodeGenerator::VisitNullishExpression(BinaryOperation* binop) {
Expression* left = binop->left();
Expression* right = binop->right();
int right_coverage_slot =
AllocateBlockCoverageSlotIfEnabled(binop, SourceRangeKind::kRight);
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
if (left->IsLiteralButNotNullOrUndefined() && left->ToBooleanIsTrue()) {
builder()->Jump(test_result->NewThenLabel());
} else if (left->IsNullOrUndefinedLiteral() &&
right->IsNullOrUndefinedLiteral()) {
BuildIncrementBlockCoverageCounterIfEnabled(right_coverage_slot);
builder()->Jump(test_result->NewElseLabel());
} else {
VisitLogicalTest(Token::kNullish, left, right, right_coverage_slot);
}
test_result->SetResultConsumedByTest();
} else {
BytecodeLabels end_labels(zone());
if (VisitNullishSubExpression(left, &end_labels, right_coverage_slot)) {
return;
}
VisitInHoleCheckElisionScopeForAccumulatorValue(right);
end_labels.Bind(builder());
}
}
void BytecodeGenerator::VisitNaryNullishExpression(NaryOperation* expr) {
Expression* first = expr->first();
DCHECK_GT(expr->subsequent_length(), 0);
NaryCodeCoverageSlots coverage_slots(this, expr);
if (execution_result()->IsTest()) {
TestResultScope* test_result = execution_result()->AsTest();
if (first->IsLiteralButNotNullOrUndefined() && first->ToBooleanIsTrue()) {
builder()->Jump(test_result->NewThenLabel());
} else {
VisitNaryLogicalTest(Token::kNullish, expr, &coverage_slots);
}
test_result->SetResultConsumedByTest();
} else {
BytecodeLabels end_labels(zone());
if (VisitNullishSubExpression(first, &end_labels,
coverage_slots.GetSlotFor(0))) {
return;
}
HoleCheckElisionScope elider(this);
for (size_t i = 0; i < expr->subsequent_length() - 1; ++i) {
if (VisitNullishSubExpression(expr->subsequent(i), &end_labels,
coverage_slots.GetSlotFor(i + 1))) {
return;
}
}
// We have to visit the last value even if it's nullish, because we need its
// actual value.
VisitForAccumulatorValue(expr->subsequent(expr->subsequent_length() - 1));
end_labels.Bind(builder());
}
}
void BytecodeGenerator::BuildNewLocalActivationContext() {
ValueResultScope value_execution_result(this);
Scope* scope = closure_scope();
DCHECK_EQ(current_scope(), closure_scope());
// Create the appropriate context.
DCHECK(scope->is_function_scope() || scope->is_eval_scope());
int slot_count = scope->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
if (slot_count <= ConstructorBuiltins::MaximumFunctionContextSlots()) {
switch (scope->scope_type()) {
case EVAL_SCOPE:
builder()->CreateEvalContext(scope, slot_count);
break;
case FUNCTION_SCOPE:
builder()->CreateFunctionContext(scope, slot_count);
break;
default:
UNREACHABLE();
}
} else {
Register arg = register_allocator()->NewRegister();
builder()->LoadLiteral(scope).StoreAccumulatorInRegister(arg).CallRuntime(
Runtime::kNewFunctionContext, arg);
register_allocator()->ReleaseRegister(arg);
}
}
void BytecodeGenerator::BuildLocalActivationContextInitialization() {
DeclarationScope* scope = closure_scope();
if (scope->has_this_declaration() && scope->receiver()->IsContextSlot()) {
Variable* variable = scope->receiver();
Register receiver(builder()->Receiver());
// Context variable (at bottom of the context chain).
DCHECK_EQ(0, scope->ContextChainLength(variable->scope()));
builder()->LoadAccumulatorWithRegister(receiver).StoreContextSlot(
execution_context()->reg(), variable, 0);
}
// Copy parameters into context if necessary.
int num_parameters = scope->num_parameters();
for (int i = 0; i < num_parameters; i++) {
Variable* variable = scope->parameter(i);
if (!variable->IsContextSlot()) continue;
Register parameter(builder()->Parameter(i));
// Context variable (at bottom of the context chain).
DCHECK_EQ(0, scope->ContextChainLength(variable->scope()));
builder()->LoadAccumulatorWithRegister(parameter).StoreContextSlot(
execution_context()->reg(), variable, 0);
}
}
void BytecodeGenerator::BuildNewLocalBlockContext(Scope* scope) {
ValueResultScope value_execution_result(this);
DCHECK(scope->is_block_scope());
builder()->CreateBlockContext(scope);
}
void BytecodeGenerator::BuildNewLocalWithContext(Scope* scope) {
ValueResultScope value_execution_result(this);
Register extension_object = register_allocator()->NewRegister();
builder()->ToObject(extension_object);
builder()->CreateWithContext(extension_object, scope);
register_allocator()->ReleaseRegister(extension_object);
}
void BytecodeGenerator::BuildNewLocalCatchContext(Scope* scope) {
ValueResultScope value_execution_result(this);
DCHECK(scope->catch_variable()->IsContextSlot());
Register exception = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(exception);
builder()->CreateCatchContext(exception, scope);
register_allocator()->ReleaseRegister(exception);
}
void BytecodeGenerator::VisitLiteralAccessor(LiteralProperty* property,
Register value_out) {
if (property == nullptr) {
builder()->LoadNull().StoreAccumulatorInRegister(value_out);
} else {
VisitForRegisterValue(property->value(), value_out);
}
}
void BytecodeGenerator::VisitArgumentsObject(Variable* variable) {
if (variable == nullptr) return;
DCHECK(variable->IsContextSlot() || variable->IsStackAllocated());
// Allocate and initialize a new arguments object and assign to the
// {arguments} variable.
builder()->CreateArguments(closure_scope()->GetArgumentsType());
BuildVariableAssignment(variable, Token::kAssign, HoleCheckMode::kElided);
}
void BytecodeGenerator::VisitRestArgumentsArray(Variable* rest) {
if (rest == nullptr) return;
// Allocate and initialize a new rest parameter and assign to the {rest}
// variable.
builder()->CreateArguments(CreateArgumentsType::kRestParameter);
DCHECK(rest->IsContextSlot() || rest->IsStackAllocated());
BuildVariableAssignment(rest, Token::kAssign, HoleCheckMode::kElided);
}
void BytecodeGenerator::VisitThisFunctionVariable(Variable* variable) {
if (variable == nullptr) return;
// Store the closure we were called with in the given variable.
builder()->LoadAccumulatorWithRegister(Register::function_closure());
BuildVariableAssignment(variable, Token::kInit, HoleCheckMode::kElided);
}
void BytecodeGenerator::VisitNewTargetVariable(Variable* variable) {
if (variable == nullptr) return;
// The generator resume trampoline abuses the new.target register
// to pass in the generator object. In ordinary calls, new.target is always
// undefined because generator functions are non-constructible, so don't
// assign anything to the new.target variable.
if (IsResumableFunction(info()->literal()->kind())) return;
if (variable->location() == VariableLocation::LOCAL) {
// The new.target register was already assigned by entry trampoline.
DCHECK_EQ(incoming_new_target().index(),
GetRegisterForLocalVariable(variable).index());
return;
}
// Store the new target we were called with in the given variable.
builder()->LoadAccumulatorWithRegister(incoming_new_target());
BuildVariableAssignment(variable, Token::kInit, HoleCheckMode::kElided);
}
void BytecodeGenerator::BuildGeneratorObjectVariableInitialization() {
DCHECK(IsResumableFunction(info()->literal()->kind()));
Variable* generator_object_var = closure_scope()->generator_object_var();
RegisterAllocationScope register_scope(this);
RegisterList args = register_allocator()->NewRegisterList(2);
Runtime::FunctionId function_id =
((IsAsyncFunction(info()->literal()->kind()) &&
!IsAsyncGeneratorFunction(info()->literal()->kind())) ||
IsModuleWithTopLevelAwait(info()->literal()->kind()))
? Runtime::kInlineAsyncFunctionEnter
: Runtime::kInlineCreateJSGeneratorObject;
builder()
->MoveRegister(Register::function_closure(), args[0])
.MoveRegister(builder()->Receiver(), args[1])
.CallRuntime(function_id, args)
.StoreAccumulatorInRegister(generator_object());
if (generator_object_var->location() == VariableLocation::LOCAL) {
// The generator object register is already set to the variable's local
// register.
DCHECK_EQ(generator_object().index(),
GetRegisterForLocalVariable(generator_object_var).index());
} else {
BuildVariableAssignment(generator_object_var, Token::kInit,
HoleCheckMode::kElided);
}
}
void BytecodeGenerator::BuildPushUndefinedIntoRegisterList(
RegisterList* reg_list) {
Register reg = register_allocator()->GrowRegisterList(reg_list);
builder()->LoadUndefined().StoreAccumulatorInRegister(reg);
}
void BytecodeGenerator::BuildLoadPropertyKey(LiteralProperty* property,
Register out_reg) {
if (property->key()->IsStringLiteral()) {
builder()
->LoadLiteral(property->key()->AsLiteral()->AsRawString())
.StoreAccumulatorInRegister(out_reg);
} else {
VisitForAccumulatorValue(property->key());
builder()->ToName().StoreAccumulatorInRegister(out_reg);
}
}
int BytecodeGenerator::AllocateBlockCoverageSlotIfEnabled(
AstNode* node, SourceRangeKind kind) {
return (block_coverage_builder_ == nullptr)
? BlockCoverageBuilder::kNoCoverageArraySlot
: block_coverage_builder_->AllocateBlockCoverageSlot(node, kind);
}
int BytecodeGenerator::AllocateNaryBlockCoverageSlotIfEnabled(
NaryOperation* node, size_t index) {
return (block_coverage_builder_ == nullptr)
? BlockCoverageBuilder::kNoCoverageArraySlot
: block_coverage_builder_->AllocateNaryBlockCoverageSlot(node,
index);
}
int BytecodeGenerator::AllocateConditionalChainBlockCoverageSlotIfEnabled(
ConditionalChain* node, SourceRangeKind kind, size_t index) {
return (block_coverage_builder_ == nullptr)
? BlockCoverageBuilder::kNoCoverageArraySlot
: block_coverage_builder_
->AllocateConditionalChainBlockCoverageSlot(node, kind,
index);
}
void BytecodeGenerator::BuildIncrementBlockCoverageCounterIfEnabled(
AstNode* node, SourceRangeKind kind) {
if (block_coverage_builder_ == nullptr) return;
block_coverage_builder_->IncrementBlockCounter(node, kind);
}
void BytecodeGenerator::BuildIncrementBlockCoverageCounterIfEnabled(
int coverage_array_slot) {
if (block_coverage_builder_ != nullptr) {
block_coverage_builder_->IncrementBlockCounter(coverage_array_slot);
}
}
// Visits the expression |expr| and places the result in the accumulator.
BytecodeGenerator::TypeHint BytecodeGenerator::VisitForAccumulatorValue(
Expression* expr) {
ValueResultScope accumulator_scope(this);
return VisitForAccumulatorValueImpl(expr, &accumulator_scope);
}
BytecodeGenerator::TypeHint
BytecodeGenerator::VisitForAccumulatorValueAsPropertyKey(Expression* expr) {
ValueResultScope accumulator_scope(this,
ValueResultScope::kValueAsPropertyKey);
return VisitForAccumulatorValueImpl(expr, &accumulator_scope);
}
BytecodeGenerator::TypeHint BytecodeGenerator::VisitForAccumulatorValueImpl(
Expression* expr, ValueResultScope* accumulator_scope) {
Visit(expr);
// Record the type hint for the result of current expression in accumulator.
const TypeHint type_hint = accumulator_scope->type_hint();
BytecodeRegisterOptimizer* optimizer = builder()->GetRegisterOptimizer();
if (optimizer && type_hint != TypeHint::kUnknown) {
optimizer->SetTypeHintForAccumulator(type_hint);
}
return type_hint;
}
void BytecodeGenerator::VisitForAccumulatorValueOrTheHole(Expression* expr) {
if (expr == nullptr) {
builder()->LoadTheHole();
} else {
VisitForAccumulatorValue(expr);
}
}
// Visits the expression |expr| and discards the result.
void BytecodeGenerator::VisitForEffect(Expression* expr) {
EffectResultScope effect_scope(this);
Visit(expr);
}
// Visits the expression |expr| and returns the register containing
// the expression result.
Register BytecodeGenerator::VisitForRegisterValue(Expression* expr) {
VisitForAccumulatorValue(expr);
Register result = register_allocator()->NewRegister();
builder()->StoreAccumulatorInRegister(result);
return result;
}
// Visits the expression |expr| and stores the expression result in
// |destination|.
void BytecodeGenerator::VisitForRegisterValue(Expression* expr,
Register destination) {
ValueResultScope register_scope(this);
Visit(expr);
builder()->StoreAccumulatorInRegister(destination);
}
// Visits the expression |expr| and pushes the result into a new register
// added to the end of |reg_list|.
void BytecodeGenerator::VisitAndPushIntoRegisterList(Expression* expr,
RegisterList* reg_list) {
{
ValueResultScope register_scope(this);
Visit(expr);
}
// Grow the register list after visiting the expression to avoid reserving
// the register across the expression evaluation, which could cause memory
// leaks for deep expressions due to dead objects being kept alive by pointers
// in registers.
Register destination = register_allocator()->GrowRegisterList(reg_list);
builder()->StoreAccumulatorInRegister(destination);
}
void BytecodeGenerator::BuildTest(ToBooleanMode mode,
BytecodeLabels* then_labels,
BytecodeLabels* else_labels,
TestFallthrough fallthrough) {
switch (fallthrough) {
case TestFallthrough::kThen:
builder()->JumpIfFalse(mode, else_labels->New());
break;
case TestFallthrough::kElse:
builder()->JumpIfTrue(mode, then_labels->New());
break;
case TestFallthrough::kNone:
builder()->JumpIfTrue(mode, then_labels->New());
builder()->Jump(else_labels->New());
break;
}
}
// Visits the expression |expr| for testing its boolean value and jumping to the
// |then| or |other| label depending on value and short-circuit semantics
void BytecodeGenerator::VisitForTest(Expression* expr,
BytecodeLabels* then_labels,
BytecodeLabels* else_labels,
TestFallthrough fallthrough) {
bool result_consumed;
TypeHint type_hint;
{
// To make sure that all temporary registers are returned before generating
// jumps below, we ensure that the result scope is deleted before doing so.
// Dead registers might be materialized otherwise.
TestResultScope test_result(this, then_labels, else_labels, fallthrough);
Visit(expr);
result_consumed = test_result.result_consumed_by_test();
type_hint = test_result.type_hint();
// Labels and fallthrough might have been mutated, so update based on
// TestResultScope.
then_labels = test_result.then_labels();
else_labels = test_result.else_labels();
fallthrough = test_result.fallthrough();
}
if (!result_consumed) {
BuildTest(ToBooleanModeFromTypeHint(type_hint), then_labels, else_labels,
fallthrough);
}
}
// Visits the expression |expr| for testing its nullish value and jumping to the
// |then| or |other| label depending on value and short-circuit semantics
void BytecodeGenerator::VisitForNullishTest(Expression* expr,
BytecodeLabels* then_labels,
BytecodeLabels* test_next_labels,
BytecodeLabels* else_labels) {
// Nullish short circuits on undefined or null, otherwise we fall back to
// BuildTest with no fallthrough.
// TODO(joshualitt): We should do this in a TestResultScope.
TypeHint type_hint = VisitForAccumulatorValue(expr);
ToBooleanMode mode = ToBooleanModeFromTypeHint(type_hint);
// Skip the nullish shortcircuit if we already have a boolean.
if (mode != ToBooleanMode::kAlreadyBoolean) {
builder()->JumpIfUndefinedOrNull(test_next_labels->New());
}
BuildTest(mode, then_labels, else_labels, TestFallthrough::kNone);
}
void BytecodeGenerator::VisitInSameTestExecutionScope(Expression* expr) {
DCHECK(execution_result()->IsTest());
{
RegisterAllocationScope reg_scope(this);
Visit(expr);
}
if (!execution_result()->AsTest()->result_consumed_by_test()) {
TestResultScope* result_scope = execution_result()->AsTest();
BuildTest(ToBooleanModeFromTypeHint(result_scope->type_hint()),
result_scope->then_labels(), result_scope->else_labels(),
result_scope->fallthrough());
result_scope->SetResultConsumedByTest();
}
}
void BytecodeGenerator::VisitInScope(Statement* stmt, Scope* scope) {
DCHECK(scope->declarations()->is_empty());
CurrentScope current_scope(this, scope);
ContextScope context_scope(this, scope);
Visit(stmt);
}
template <typename T>
void BytecodeGenerator::VisitInHoleCheckElisionScope(T* node) {
HoleCheckElisionScope elider(this);
Visit(node);
}
BytecodeGenerator::TypeHint
BytecodeGenerator::VisitInHoleCheckElisionScopeForAccumulatorValue(
Expression* expr) {
HoleCheckElisionScope elider(this);
return VisitForAccumulatorValue(expr);
}
Register BytecodeGenerator::GetRegisterForLocalVariable(Variable* variable) {
DCHECK_EQ(VariableLocation::LOCAL, variable->location());
return builder()->Local(variable->index());
}
BytecodeGenerator::TypeHint BytecodeGenerator::GetTypeHintForLocalVariable(
Variable* variable) {
BytecodeRegisterOptimizer* optimizer = builder()->GetRegisterOptimizer();
if (optimizer) {
Register reg = GetRegisterForLocalVariable(variable);
return optimizer->GetTypeHint(reg);
}
return TypeHint::kAny;
}
FunctionKind BytecodeGenerator::function_kind() const {
return info()->literal()->kind();
}
LanguageMode BytecodeGenerator::language_mode() const {
return current_scope()->language_mode();
}
Register BytecodeGenerator::incoming_new_target() const {
DCHECK(!IsResumableFunction(info()->literal()->kind()));
SBXCHECK(incoming_new_target_or_generator_.is_valid());
return incoming_new_target_or_generator_;
}
Register BytecodeGenerator::generator_object() const {
DCHECK(IsResumableFunction(info()->literal()->kind()));
SBXCHECK(incoming_new_target_or_generator_.is_valid());
return incoming_new_target_or_generator_;
}
FeedbackVectorSpec* BytecodeGenerator::feedback_spec() {
return info()->feedback_vector_spec();
}
int BytecodeGenerator::feedback_index(FeedbackSlot slot) const {
DCHECK(!slot.IsInvalid());
return FeedbackVector::GetIndex(slot);
}
FeedbackSlot BytecodeGenerator::GetCachedLoadGlobalICSlot(
TypeofMode typeof_mode, Variable* variable) {
FeedbackSlotCache::SlotKind slot_kind =
typeof_mode == TypeofMode::kInside
? FeedbackSlotCache::SlotKind::kLoadGlobalInsideTypeof
: FeedbackSlotCache::SlotKind::kLoadGlobalNotInsideTypeof;
FeedbackSlot slot(feedback_slot_cache()->Get(slot_kind, variable));
if (!slot.IsInvalid()) {
return slot;
}
slot = feedback_spec()->AddLoadGlobalICSlot(typeof_mode);
feedback_slot_cache()->Put(slot_kind, variable, feedback_index(slot));
return slot;
}
FeedbackSlot BytecodeGenerator::GetCachedStoreGlobalICSlot(
LanguageMode language_mode, Variable* variable) {
FeedbackSlotCache::SlotKind slot_kind =
is_strict(language_mode)
? FeedbackSlotCache::SlotKind::kStoreGlobalStrict
: FeedbackSlotCache::SlotKind::kStoreGlobalSloppy;
FeedbackSlot slot(feedback_slot_cache()->Get(slot_kind, variable));
if (!slot.IsInvalid()) {
return slot;
}
slot = feedback_spec()->AddStoreGlobalICSlot(language_mode);
feedback_slot_cache()->Put(slot_kind, variable, feedback_index(slot));
return slot;
}
FeedbackSlot BytecodeGenerator::GetCachedLoadICSlot(const Expression* expr,
const AstRawString* name) {
DCHECK(!expr->IsSuperPropertyReference());
if (!v8_flags.ignition_share_named_property_feedback) {
return feedback_spec()->AddLoadICSlot();
}
FeedbackSlotCache::SlotKind slot_kind =
FeedbackSlotCache::SlotKind::kLoadProperty;
if (!expr->IsVariableProxy()) {
return feedback_spec()->AddLoadICSlot();
}
const VariableProxy* proxy = expr->AsVariableProxy();
FeedbackSlot slot(
feedback_slot_cache()->Get(slot_kind, proxy->var()->index(), name));
if (!slot.IsInvalid()) {
return slot;
}
slot = feedback_spec()->AddLoadICSlot();
feedback_slot_cache()->Put(slot_kind, proxy->var()->index(), name,
feedback_index(slot));
return slot;
}
FeedbackSlot BytecodeGenerator::GetCachedLoadSuperICSlot(
const AstRawString* name) {
if (!v8_flags.ignition_share_named_property_feedback) {
return feedback_spec()->AddLoadICSlot();
}
FeedbackSlotCache::SlotKind slot_kind =
FeedbackSlotCache::SlotKind::kLoadSuperProperty;
FeedbackSlot slot(feedback_slot_cache()->Get(slot_kind, name));
if (!slot.IsInvalid()) {
return slot;
}
slot = feedback_spec()->AddLoadICSlot();
feedback_slot_cache()->Put(slot_kind, name, feedback_index(slot));
return slot;
}
FeedbackSlot BytecodeGenerator::GetCachedStoreICSlot(const Expression* expr,
const AstRawString* name) {
if (!v8_flags.ignition_share_named_property_feedback) {
return feedback_spec()->AddStoreICSlot(language_mode());
}
FeedbackSlotCache::SlotKind slot_kind =
is_strict(language_mode()) ? FeedbackSlotCache::SlotKind::kSetNamedStrict
: FeedbackSlotCache::SlotKind::kSetNamedSloppy;
if (!expr->IsVariableProxy()) {
return feedback_spec()->AddStoreICSlot(language_mode());
}
const VariableProxy* proxy = expr->AsVariableProxy();
FeedbackSlot slot(
feedback_slot_cache()->Get(slot_kind, proxy->var()->index(), name));
if (!slot.IsInvalid()) {
return slot;
}
slot = feedback_spec()->AddStoreICSlot(language_mode());
feedback_slot_cache()->Put(slot_kind, proxy->var()->index(), name,
feedback_index(slot));
return slot;
}
int BytecodeGenerator::GetCachedCreateClosureSlot(FunctionLiteral* literal) {
FeedbackSlotCache::SlotKind slot_kind =
FeedbackSlotCache::SlotKind::kClosureFeedbackCell;
int index = feedback_slot_cache()->Get(slot_kind, literal);
if (index != -1) {
return index;
}
index = feedback_spec()->AddCreateClosureParameterCount(
JSParameterCount(literal->parameter_count()));
feedback_slot_cache()->Put(slot_kind, literal, index);
return index;
}
FeedbackSlot BytecodeGenerator::GetDummyCompareICSlot() {
return dummy_feedback_slot_.Get();
}
} // namespace interpreter
} // namespace internal
} // namespace v8