blob: 382b14ee189b8e8f343dfe187fdec7cc504cdb52 [file] [log] [blame]
// Copyright 2012 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/parsing/parser.h"
#include <algorithm>
#include <memory>
#include "src/ast/ast-function-literal-id-reindexer.h"
#include "src/ast/ast-traversal-visitor.h"
#include "src/ast/ast.h"
#include "src/bailout-reason.h"
#include "src/base/platform/platform.h"
#include "src/char-predicates-inl.h"
#include "src/compiler-dispatcher/compiler-dispatcher.h"
#include "src/conversions-inl.h"
#include "src/log.h"
#include "src/messages.h"
#include "src/objects/scope-info.h"
#include "src/parsing/duplicate-finder.h"
#include "src/parsing/expression-scope-reparenter.h"
#include "src/parsing/parse-info.h"
#include "src/parsing/rewriter.h"
#include "src/runtime/runtime.h"
#include "src/string-stream.h"
#include "src/tracing/trace-event.h"
namespace v8 {
namespace internal {
// Helper for putting parts of the parse results into a temporary zone when
// parsing inner function bodies.
class DiscardableZoneScope {
public:
DiscardableZoneScope(Parser* parser, Zone* temp_zone, bool use_temp_zone)
: fni_(parser->ast_value_factory_, temp_zone),
parser_(parser),
prev_fni_(parser->fni_),
prev_zone_(parser->zone_),
prev_allow_lazy_(parser->allow_lazy_),
prev_temp_zoned_(parser->temp_zoned_) {
if (use_temp_zone) {
DCHECK(!parser_->temp_zoned_);
parser_->allow_lazy_ = false;
parser_->temp_zoned_ = true;
parser_->fni_ = &fni_;
parser_->zone_ = temp_zone;
parser_->factory()->set_zone(temp_zone);
if (parser_->reusable_preparser_ != nullptr) {
parser_->reusable_preparser_->zone_ = temp_zone;
parser_->reusable_preparser_->factory()->set_zone(temp_zone);
}
}
}
void Reset() {
parser_->fni_ = prev_fni_;
parser_->zone_ = prev_zone_;
parser_->factory()->set_zone(prev_zone_);
parser_->allow_lazy_ = prev_allow_lazy_;
parser_->temp_zoned_ = prev_temp_zoned_;
if (parser_->reusable_preparser_ != nullptr) {
parser_->reusable_preparser_->zone_ = prev_zone_;
parser_->reusable_preparser_->factory()->set_zone(prev_zone_);
}
}
~DiscardableZoneScope() { Reset(); }
private:
FuncNameInferrer fni_;
Parser* parser_;
FuncNameInferrer* prev_fni_;
Zone* prev_zone_;
bool prev_allow_lazy_;
bool prev_temp_zoned_;
DISALLOW_COPY_AND_ASSIGN(DiscardableZoneScope);
};
FunctionLiteral* Parser::DefaultConstructor(const AstRawString* name,
bool call_super, int pos,
int end_pos) {
int expected_property_count = -1;
const int parameter_count = 0;
FunctionKind kind = call_super ? FunctionKind::kDefaultDerivedConstructor
: FunctionKind::kDefaultBaseConstructor;
DeclarationScope* function_scope = NewFunctionScope(kind);
SetLanguageMode(function_scope, LanguageMode::kStrict);
// Set start and end position to the same value
function_scope->set_start_position(pos);
function_scope->set_end_position(pos);
ZonePtrList<Statement>* body = nullptr;
{
FunctionState function_state(&function_state_, &scope_, function_scope);
body = new (zone()) ZonePtrList<Statement>(call_super ? 2 : 1, zone());
if (call_super) {
// Create a SuperCallReference and handle in BytecodeGenerator.
auto constructor_args_name = ast_value_factory()->empty_string();
bool is_duplicate;
bool is_rest = true;
bool is_optional = false;
Variable* constructor_args = function_scope->DeclareParameter(
constructor_args_name, VariableMode::kTemporary, is_optional, is_rest,
&is_duplicate, ast_value_factory(), pos);
ZonePtrList<Expression>* args =
new (zone()) ZonePtrList<Expression>(1, zone());
Spread* spread_args = factory()->NewSpread(
factory()->NewVariableProxy(constructor_args), pos, pos);
args->Add(spread_args, zone());
Expression* super_call_ref = NewSuperCallReference(pos);
Expression* call = factory()->NewCall(super_call_ref, args, pos);
body->Add(factory()->NewReturnStatement(call, pos), zone());
}
expected_property_count = function_state.expected_property_count();
}
FunctionLiteral* function_literal = factory()->NewFunctionLiteral(
name, function_scope, body, expected_property_count, parameter_count,
parameter_count, FunctionLiteral::kNoDuplicateParameters,
FunctionLiteral::kAnonymousExpression, default_eager_compile_hint(), pos,
true, GetNextFunctionLiteralId());
return function_literal;
}
// ----------------------------------------------------------------------------
// The CHECK_OK macro is a convenient macro to enforce error
// handling for functions that may fail (by returning !*ok).
//
// CAUTION: This macro appends extra statements after a call,
// thus it must never be used where only a single statement
// is correct (e.g. an if statement branch w/o braces)!
#define CHECK_OK_VALUE(x) ok); \
if (!*ok) return x; \
((void)0
#define DUMMY ) // to make indentation work
#undef DUMMY
#define CHECK_OK CHECK_OK_VALUE(nullptr)
#define CHECK_OK_VOID CHECK_OK_VALUE(this->Void())
#define CHECK_FAILED /**/); \
if (failed_) return nullptr; \
((void)0
#define DUMMY ) // to make indentation work
#undef DUMMY
// ----------------------------------------------------------------------------
// Implementation of Parser
bool Parser::ShortcutNumericLiteralBinaryExpression(Expression** x,
Expression* y,
Token::Value op, int pos) {
if ((*x)->IsNumberLiteral() && y->IsNumberLiteral()) {
double x_val = (*x)->AsLiteral()->AsNumber();
double y_val = y->AsLiteral()->AsNumber();
switch (op) {
case Token::ADD:
*x = factory()->NewNumberLiteral(x_val + y_val, pos);
return true;
case Token::SUB:
*x = factory()->NewNumberLiteral(x_val - y_val, pos);
return true;
case Token::MUL:
*x = factory()->NewNumberLiteral(x_val * y_val, pos);
return true;
case Token::DIV:
*x = factory()->NewNumberLiteral(x_val / y_val, pos);
return true;
case Token::BIT_OR: {
int value = DoubleToInt32(x_val) | DoubleToInt32(y_val);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::BIT_AND: {
int value = DoubleToInt32(x_val) & DoubleToInt32(y_val);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::BIT_XOR: {
int value = DoubleToInt32(x_val) ^ DoubleToInt32(y_val);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::SHL: {
int value = DoubleToInt32(x_val) << (DoubleToInt32(y_val) & 0x1F);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::SHR: {
uint32_t shift = DoubleToInt32(y_val) & 0x1F;
uint32_t value = DoubleToUint32(x_val) >> shift;
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::SAR: {
uint32_t shift = DoubleToInt32(y_val) & 0x1F;
int value = ArithmeticShiftRight(DoubleToInt32(x_val), shift);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::EXP: {
double value = Pow(x_val, y_val);
int int_value = static_cast<int>(value);
*x = factory()->NewNumberLiteral(
int_value == value && value != -0.0 ? int_value : value, pos);
return true;
}
default:
break;
}
}
return false;
}
bool Parser::CollapseNaryExpression(Expression** x, Expression* y,
Token::Value op, int pos,
const SourceRange& range) {
// Filter out unsupported ops.
if (!Token::IsBinaryOp(op) || op == Token::EXP) return false;
// Convert *x into an nary operation with the given op, returning false if
// this is not possible.
NaryOperation* nary = nullptr;
if ((*x)->IsBinaryOperation()) {
BinaryOperation* binop = (*x)->AsBinaryOperation();
if (binop->op() != op) return false;
nary = factory()->NewNaryOperation(op, binop->left(), 2);
nary->AddSubsequent(binop->right(), binop->position());
ConvertBinaryToNaryOperationSourceRange(binop, nary);
*x = nary;
} else if ((*x)->IsNaryOperation()) {
nary = (*x)->AsNaryOperation();
if (nary->op() != op) return false;
} else {
return false;
}
// Append our current expression to the nary operation.
// TODO(leszeks): Do some literal collapsing here if we're appending Smi or
// String literals.
nary->AddSubsequent(y, pos);
AppendNaryOperationSourceRange(nary, range);
return true;
}
Expression* Parser::BuildUnaryExpression(Expression* expression,
Token::Value op, int pos) {
DCHECK_NOT_NULL(expression);
const Literal* literal = expression->AsLiteral();
if (literal != nullptr) {
if (op == Token::NOT) {
// Convert the literal to a boolean condition and negate it.
return factory()->NewBooleanLiteral(literal->ToBooleanIsFalse(), pos);
} else if (literal->IsNumberLiteral()) {
// Compute some expressions involving only number literals.
double value = literal->AsNumber();
switch (op) {
case Token::ADD:
return expression;
case Token::SUB:
return factory()->NewNumberLiteral(-value, pos);
case Token::BIT_NOT:
return factory()->NewNumberLiteral(~DoubleToInt32(value), pos);
default:
break;
}
}
}
return factory()->NewUnaryOperation(op, expression, pos);
}
Expression* Parser::NewThrowError(Runtime::FunctionId id,
MessageTemplate::Template message,
const AstRawString* arg, int pos) {
ZonePtrList<Expression>* args =
new (zone()) ZonePtrList<Expression>(2, zone());
args->Add(factory()->NewSmiLiteral(message, pos), zone());
args->Add(factory()->NewStringLiteral(arg, pos), zone());
CallRuntime* call_constructor = factory()->NewCallRuntime(id, args, pos);
return factory()->NewThrow(call_constructor, pos);
}
Expression* Parser::NewSuperPropertyReference(int pos) {
// this_function[home_object_symbol]
VariableProxy* this_function_proxy =
NewUnresolved(ast_value_factory()->this_function_string(), pos);
Expression* home_object_symbol_literal = factory()->NewSymbolLiteral(
AstSymbol::kHomeObjectSymbol, kNoSourcePosition);
Expression* home_object = factory()->NewProperty(
this_function_proxy, home_object_symbol_literal, pos);
return factory()->NewSuperPropertyReference(
ThisExpression(pos)->AsVariableProxy(), home_object, pos);
}
Expression* Parser::NewSuperCallReference(int pos) {
VariableProxy* new_target_proxy =
NewUnresolved(ast_value_factory()->new_target_string(), pos);
VariableProxy* this_function_proxy =
NewUnresolved(ast_value_factory()->this_function_string(), pos);
return factory()->NewSuperCallReference(
ThisExpression(pos)->AsVariableProxy(), new_target_proxy,
this_function_proxy, pos);
}
Expression* Parser::NewTargetExpression(int pos) {
auto proxy = NewUnresolved(ast_value_factory()->new_target_string(), pos);
proxy->set_is_new_target();
return proxy;
}
Expression* Parser::ImportMetaExpression(int pos) {
return factory()->NewCallRuntime(
Runtime::kInlineGetImportMetaObject,
new (zone()) ZonePtrList<Expression>(0, zone()), pos);
}
Literal* Parser::ExpressionFromLiteral(Token::Value token, int pos) {
switch (token) {
case Token::NULL_LITERAL:
return factory()->NewNullLiteral(pos);
case Token::TRUE_LITERAL:
return factory()->NewBooleanLiteral(true, pos);
case Token::FALSE_LITERAL:
return factory()->NewBooleanLiteral(false, pos);
case Token::SMI: {
uint32_t value = scanner()->smi_value();
return factory()->NewSmiLiteral(value, pos);
}
case Token::NUMBER: {
double value = scanner()->DoubleValue();
return factory()->NewNumberLiteral(value, pos);
}
case Token::BIGINT:
return factory()->NewBigIntLiteral(
AstBigInt(scanner()->CurrentLiteralAsCString(zone())), pos);
default:
DCHECK(false);
}
return nullptr;
}
Expression* Parser::NewV8Intrinsic(const AstRawString* name,
ZonePtrList<Expression>* args, int pos,
bool* ok) {
if (extension_ != nullptr) {
// The extension structures are only accessible while parsing the
// very first time, not when reparsing because of lazy compilation.
GetClosureScope()->ForceEagerCompilation();
}
DCHECK(name->is_one_byte());
const Runtime::Function* function =
Runtime::FunctionForName(name->raw_data(), name->length());
if (function != nullptr) {
// Check for possible name clash.
DCHECK_EQ(Context::kNotFound,
Context::IntrinsicIndexForName(name->raw_data(), name->length()));
// Check for built-in IS_VAR macro.
if (function->function_id == Runtime::kIS_VAR) {
DCHECK_EQ(Runtime::RUNTIME, function->intrinsic_type);
// %IS_VAR(x) evaluates to x if x is a variable,
// leads to a parse error otherwise. Could be implemented as an
// inline function %_IS_VAR(x) to eliminate this special case.
if (args->length() == 1 && args->at(0)->AsVariableProxy() != nullptr) {
return args->at(0);
} else {
ReportMessage(MessageTemplate::kNotIsvar);
*ok = false;
return nullptr;
}
}
// Check that the expected number of arguments are being passed.
if (function->nargs != -1 && function->nargs != args->length()) {
ReportMessage(MessageTemplate::kRuntimeWrongNumArgs);
*ok = false;
return nullptr;
}
return factory()->NewCallRuntime(function, args, pos);
}
int context_index =
Context::IntrinsicIndexForName(name->raw_data(), name->length());
// Check that the function is defined.
if (context_index == Context::kNotFound) {
ReportMessage(MessageTemplate::kNotDefined, name);
*ok = false;
return nullptr;
}
return factory()->NewCallRuntime(context_index, args, pos);
}
Parser::Parser(ParseInfo* info)
: ParserBase<Parser>(info->zone(), &scanner_, info->stack_limit(),
info->extension(), info->GetOrCreateAstValueFactory(),
info->pending_error_handler(),
info->runtime_call_stats(), info->logger(),
info->script().is_null() ? -1 : info->script()->id(),
info->is_module(), true),
scanner_(info->unicode_cache()),
reusable_preparser_(nullptr),
mode_(PARSE_EAGERLY), // Lazy mode must be set explicitly.
source_range_map_(info->source_range_map()),
target_stack_(nullptr),
total_preparse_skipped_(0),
temp_zoned_(false),
consumed_preparsed_scope_data_(info->consumed_preparsed_scope_data()),
parameters_end_pos_(info->parameters_end_pos()) {
// Even though we were passed ParseInfo, we should not store it in
// Parser - this makes sure that Isolate is not accidentally accessed via
// ParseInfo during background parsing.
DCHECK_NOT_NULL(info->character_stream());
// Determine if functions can be lazily compiled. This is necessary to
// allow some of our builtin JS files to be lazily compiled. These
// builtins cannot be handled lazily by the parser, since we have to know
// if a function uses the special natives syntax, which is something the
// parser records.
// If the debugger requests compilation for break points, we cannot be
// aggressive about lazy compilation, because it might trigger compilation
// of functions without an outer context when setting a breakpoint through
// Debug::FindSharedFunctionInfoInScript
// We also compile eagerly for kProduceExhaustiveCodeCache.
bool can_compile_lazily = FLAG_lazy && !info->is_eager();
set_default_eager_compile_hint(can_compile_lazily
? FunctionLiteral::kShouldLazyCompile
: FunctionLiteral::kShouldEagerCompile);
allow_lazy_ = FLAG_lazy && info->allow_lazy_parsing() && !info->is_native() &&
info->extension() == nullptr && can_compile_lazily;
set_allow_natives(FLAG_allow_natives_syntax || info->is_native());
set_allow_harmony_do_expressions(FLAG_harmony_do_expressions);
set_allow_harmony_public_fields(FLAG_harmony_public_fields);
set_allow_harmony_static_fields(FLAG_harmony_static_fields);
set_allow_harmony_dynamic_import(FLAG_harmony_dynamic_import);
set_allow_harmony_import_meta(FLAG_harmony_import_meta);
set_allow_harmony_bigint(FLAG_harmony_bigint);
set_allow_harmony_numeric_separator(FLAG_harmony_numeric_separator);
set_allow_harmony_private_fields(FLAG_harmony_private_fields);
for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
++feature) {
use_counts_[feature] = 0;
}
}
void Parser::DeserializeScopeChain(
Isolate* isolate, ParseInfo* info,
MaybeHandle<ScopeInfo> maybe_outer_scope_info) {
// TODO(wingo): Add an outer SCRIPT_SCOPE corresponding to the native
// context, which will have the "this" binding for script scopes.
DeclarationScope* script_scope = NewScriptScope();
info->set_script_scope(script_scope);
Scope* scope = script_scope;
Handle<ScopeInfo> outer_scope_info;
if (maybe_outer_scope_info.ToHandle(&outer_scope_info)) {
DCHECK(ThreadId::Current().Equals(isolate->thread_id()));
scope = Scope::DeserializeScopeChain(
isolate, zone(), *outer_scope_info, script_scope, ast_value_factory(),
Scope::DeserializationMode::kScopesOnly);
}
original_scope_ = scope;
}
namespace {
void MaybeResetCharacterStream(ParseInfo* info, FunctionLiteral* literal) {
// Don't reset the character stream if there is an asm.js module since it will
// be used again by the asm-parser.
if (!FLAG_stress_validate_asm &&
(literal == nullptr || !literal->scope()->ContainsAsmModule())) {
info->ResetCharacterStream();
}
}
} // namespace
FunctionLiteral* Parser::ParseProgram(Isolate* isolate, ParseInfo* info) {
// TODO(bmeurer): We temporarily need to pass allow_nesting = true here,
// see comment for HistogramTimerScope class.
// It's OK to use the Isolate & counters here, since this function is only
// called in the main thread.
DCHECK(parsing_on_main_thread_);
RuntimeCallTimerScope runtime_timer(
runtime_call_stats_, info->is_eval()
? RuntimeCallCounterId::kParseEval
: RuntimeCallCounterId::kParseProgram);
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.ParseProgram");
base::ElapsedTimer timer;
if (V8_UNLIKELY(FLAG_log_function_events)) timer.Start();
fni_ = new (zone()) FuncNameInferrer(ast_value_factory(), zone());
// Initialize parser state.
DeserializeScopeChain(isolate, info, info->maybe_outer_scope_info());
auto stream =
static_cast<CharacterStream<uint16_t>*>(info->character_stream());
scanner_.Initialize(stream, info->is_module());
FunctionLiteral* result = DoParseProgram(isolate, info);
MaybeResetCharacterStream(info, result);
HandleSourceURLComments(isolate, info->script());
if (V8_UNLIKELY(FLAG_log_function_events) && result != nullptr) {
double ms = timer.Elapsed().InMillisecondsF();
const char* event_name = "parse-eval";
Script* script = *info->script();
int start = -1;
int end = -1;
if (!info->is_eval()) {
event_name = "parse-script";
start = 0;
end = String::cast(script->source())->length();
}
LOG(isolate,
FunctionEvent(event_name, script->id(), ms, start, end, "", 0));
}
return result;
}
FunctionLiteral* Parser::DoParseProgram(Isolate* isolate, ParseInfo* info) {
// Note that this function can be called from the main thread or from a
// background thread. We should not access anything Isolate / heap dependent
// via ParseInfo, and also not pass it forward. If not on the main thread
// isolate will be nullptr.
DCHECK_EQ(parsing_on_main_thread_, isolate != nullptr);
DCHECK_NULL(scope_);
DCHECK_NULL(target_stack_);
ParsingModeScope mode(this, allow_lazy_ ? PARSE_LAZILY : PARSE_EAGERLY);
ResetFunctionLiteralId();
DCHECK(info->function_literal_id() == FunctionLiteral::kIdTypeTopLevel ||
info->function_literal_id() == FunctionLiteral::kIdTypeInvalid);
FunctionLiteral* result = nullptr;
{
Scope* outer = original_scope_;
DCHECK_NOT_NULL(outer);
if (info->is_eval()) {
outer = NewEvalScope(outer);
} else if (parsing_module_) {
DCHECK_EQ(outer, info->script_scope());
outer = NewModuleScope(info->script_scope());
}
DeclarationScope* scope = outer->AsDeclarationScope();
scope->set_start_position(0);
FunctionState function_state(&function_state_, &scope_, scope);
ZonePtrList<Statement>* body =
new (zone()) ZonePtrList<Statement>(16, zone());
bool ok = true;
int beg_pos = scanner()->location().beg_pos;
if (parsing_module_) {
DCHECK(info->is_module());
// Declare the special module parameter.
auto name = ast_value_factory()->empty_string();
bool is_duplicate = false;
bool is_rest = false;
bool is_optional = false;
auto var = scope->DeclareParameter(name, VariableMode::kVar, is_optional,
is_rest, &is_duplicate,
ast_value_factory(), beg_pos);
DCHECK(!is_duplicate);
var->AllocateTo(VariableLocation::PARAMETER, 0);
PrepareGeneratorVariables();
Expression* initial_yield =
BuildInitialYield(kNoSourcePosition, kGeneratorFunction);
body->Add(
factory()->NewExpressionStatement(initial_yield, kNoSourcePosition),
zone());
ParseModuleItemList(body, &ok);
ok = ok && module()->Validate(this->scope()->AsModuleScope(),
pending_error_handler(), zone());
} else if (info->is_wrapped_as_function()) {
ParseWrapped(isolate, info, body, scope, zone(), &ok);
} else {
// Don't count the mode in the use counters--give the program a chance
// to enable script-wide strict mode below.
this->scope()->SetLanguageMode(info->language_mode());
ParseStatementList(body, Token::EOS, &ok);
}
// The parser will peek but not consume EOS. Our scope logically goes all
// the way to the EOS, though.
scope->set_end_position(scanner()->peek_location().beg_pos);
if (ok && is_strict(language_mode())) {
CheckStrictOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
}
if (ok && is_sloppy(language_mode())) {
// TODO(littledan): Function bindings on the global object that modify
// pre-existing bindings should be made writable, enumerable and
// nonconfigurable if possible, whereas this code will leave attributes
// unchanged if the property already exists.
InsertSloppyBlockFunctionVarBindings(scope);
}
if (ok) {
CheckConflictingVarDeclarations(scope, &ok);
}
if (ok && info->parse_restriction() == ONLY_SINGLE_FUNCTION_LITERAL) {
if (body->length() != 1 ||
!body->at(0)->IsExpressionStatement() ||
!body->at(0)->AsExpressionStatement()->
expression()->IsFunctionLiteral()) {
ReportMessage(MessageTemplate::kSingleFunctionLiteral);
ok = false;
}
}
if (ok) {
RewriteDestructuringAssignments();
int parameter_count = parsing_module_ ? 1 : 0;
result = factory()->NewScriptOrEvalFunctionLiteral(
scope, body, function_state.expected_property_count(),
parameter_count);
result->set_suspend_count(function_state.suspend_count());
}
}
info->set_max_function_literal_id(GetLastFunctionLiteralId());
// Make sure the target stack is empty.
DCHECK_NULL(target_stack_);
return result;
}
ZonePtrList<const AstRawString>* Parser::PrepareWrappedArguments(
Isolate* isolate, ParseInfo* info, Zone* zone) {
DCHECK(parsing_on_main_thread_);
DCHECK_NOT_NULL(isolate);
Handle<FixedArray> arguments(info->script()->wrapped_arguments(), isolate);
int arguments_length = arguments->length();
ZonePtrList<const AstRawString>* arguments_for_wrapped_function =
new (zone) ZonePtrList<const AstRawString>(arguments_length, zone);
for (int i = 0; i < arguments_length; i++) {
const AstRawString* argument_string = ast_value_factory()->GetString(
Handle<String>(String::cast(arguments->get(i)), isolate));
arguments_for_wrapped_function->Add(argument_string, zone);
}
return arguments_for_wrapped_function;
}
void Parser::ParseWrapped(Isolate* isolate, ParseInfo* info,
ZonePtrList<Statement>* body,
DeclarationScope* outer_scope, Zone* zone, bool* ok) {
DCHECK_EQ(parsing_on_main_thread_, isolate != nullptr);
DCHECK(info->is_wrapped_as_function());
ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
// Set function and block state for the outer eval scope.
DCHECK(outer_scope->is_eval_scope());
FunctionState function_state(&function_state_, &scope_, outer_scope);
const AstRawString* function_name = nullptr;
Scanner::Location location(0, 0);
ZonePtrList<const AstRawString>* arguments_for_wrapped_function =
PrepareWrappedArguments(isolate, info, zone);
FunctionLiteral* function_literal = ParseFunctionLiteral(
function_name, location, kSkipFunctionNameCheck, kNormalFunction,
kNoSourcePosition, FunctionLiteral::kWrapped, LanguageMode::kSloppy,
arguments_for_wrapped_function, CHECK_OK_VOID);
Statement* return_statement = factory()->NewReturnStatement(
function_literal, kNoSourcePosition, kNoSourcePosition);
body->Add(return_statement, zone);
}
FunctionLiteral* Parser::ParseFunction(Isolate* isolate, ParseInfo* info,
Handle<SharedFunctionInfo> shared_info) {
// It's OK to use the Isolate & counters here, since this function is only
// called in the main thread.
DCHECK(parsing_on_main_thread_);
RuntimeCallTimerScope runtime_timer(runtime_call_stats_,
RuntimeCallCounterId::kParseFunction);
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.ParseFunction");
base::ElapsedTimer timer;
if (V8_UNLIKELY(FLAG_log_function_events)) timer.Start();
DeserializeScopeChain(isolate, info, info->maybe_outer_scope_info());
DCHECK_EQ(factory()->zone(), info->zone());
// Initialize parser state.
Handle<String> name(shared_info->Name(), isolate);
info->set_function_name(ast_value_factory()->GetString(name));
auto stream =
static_cast<CharacterStream<uint16_t>*>(info->character_stream());
scanner_.Initialize(stream, info->is_module());
FunctionLiteral* result =
DoParseFunction(isolate, info, info->function_name());
MaybeResetCharacterStream(info, result);
if (result != nullptr) {
Handle<String> inferred_name(shared_info->inferred_name(), isolate);
result->set_inferred_name(inferred_name);
}
if (V8_UNLIKELY(FLAG_log_function_events) && result != nullptr) {
double ms = timer.Elapsed().InMillisecondsF();
// We need to make sure that the debug-name is available.
ast_value_factory()->Internalize(isolate);
DeclarationScope* function_scope = result->scope();
std::unique_ptr<char[]> function_name = result->GetDebugName();
LOG(isolate,
FunctionEvent("parse-function", info->script()->id(), ms,
function_scope->start_position(),
function_scope->end_position(), function_name.get(),
strlen(function_name.get())));
}
return result;
}
static FunctionLiteral::FunctionType ComputeFunctionType(ParseInfo* info) {
if (info->is_wrapped_as_function()) {
return FunctionLiteral::kWrapped;
} else if (info->is_declaration()) {
return FunctionLiteral::kDeclaration;
} else if (info->is_named_expression()) {
return FunctionLiteral::kNamedExpression;
} else if (IsConciseMethod(info->function_kind()) ||
IsAccessorFunction(info->function_kind())) {
return FunctionLiteral::kAccessorOrMethod;
}
return FunctionLiteral::kAnonymousExpression;
}
FunctionLiteral* Parser::DoParseFunction(Isolate* isolate, ParseInfo* info,
const AstRawString* raw_name) {
DCHECK_EQ(parsing_on_main_thread_, isolate != nullptr);
DCHECK_NOT_NULL(raw_name);
DCHECK_NULL(scope_);
DCHECK_NULL(target_stack_);
DCHECK(ast_value_factory());
fni_ = new (zone()) FuncNameInferrer(ast_value_factory(), zone());
fni_->PushEnclosingName(raw_name);
ResetFunctionLiteralId();
DCHECK_LT(0, info->function_literal_id());
SkipFunctionLiterals(info->function_literal_id() - 1);
ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
// Place holder for the result.
FunctionLiteral* result = nullptr;
{
// Parse the function literal.
Scope* outer = original_scope_;
DeclarationScope* outer_function = outer->GetClosureScope();
DCHECK(outer);
FunctionState function_state(&function_state_, &scope_, outer_function);
BlockState block_state(&scope_, outer);
DCHECK(is_sloppy(outer->language_mode()) ||
is_strict(info->language_mode()));
FunctionLiteral::FunctionType function_type = ComputeFunctionType(info);
FunctionKind kind = info->function_kind();
bool ok = true;
if (IsArrowFunction(kind)) {
if (IsAsyncFunction(kind)) {
DCHECK(!scanner()->HasAnyLineTerminatorAfterNext());
if (!Check(Token::ASYNC)) {
CHECK(stack_overflow());
return nullptr;
}
if (!(peek_any_identifier() || peek() == Token::LPAREN)) {
CHECK(stack_overflow());
return nullptr;
}
}
// TODO(adamk): We should construct this scope from the ScopeInfo.
DeclarationScope* scope = NewFunctionScope(kind);
// This bit only needs to be explicitly set because we're
// not passing the ScopeInfo to the Scope constructor.
SetLanguageMode(scope, info->language_mode());
scope->set_start_position(info->start_position());
ExpressionClassifier formals_classifier(this);
ParserFormalParameters formals(scope);
// The outer FunctionState should not contain destructuring assignments.
DCHECK_EQ(0,
function_state.destructuring_assignments_to_rewrite().size());
{
// Parsing patterns as variable reference expression creates
// NewUnresolved references in current scope. Enter arrow function
// scope for formal parameter parsing.
BlockState block_state(&scope_, scope);
if (Check(Token::LPAREN)) {
// '(' StrictFormalParameters ')'
ParseFormalParameterList(&formals, &ok);
if (ok) ok = Check(Token::RPAREN);
} else {
// BindingIdentifier
ParseFormalParameter(&formals, &ok);
if (ok) {
DeclareFormalParameters(formals.scope, formals.params,
formals.is_simple);
}
}
}
if (ok) {
if (GetLastFunctionLiteralId() != info->function_literal_id() - 1) {
// If there were FunctionLiterals in the parameters, we need to
// renumber them to shift down so the next function literal id for
// the arrow function is the one requested.
AstFunctionLiteralIdReindexer reindexer(
stack_limit_,
(info->function_literal_id() - 1) - GetLastFunctionLiteralId());
for (auto p : formals.params) {
if (p->pattern != nullptr) reindexer.Reindex(p->pattern);
if (p->initializer != nullptr) reindexer.Reindex(p->initializer);
}
ResetFunctionLiteralId();
SkipFunctionLiterals(info->function_literal_id() - 1);
}
// Pass `accept_IN=true` to ParseArrowFunctionLiteral --- This should
// not be observable, or else the preparser would have failed.
const bool accept_IN = true;
// Any destructuring assignments in the current FunctionState
// actually belong to the arrow function itself.
const int rewritable_length = 0;
Expression* expression = ParseArrowFunctionLiteral(
accept_IN, formals, rewritable_length, &ok);
if (ok) {
// Scanning must end at the same position that was recorded
// previously. If not, parsing has been interrupted due to a stack
// overflow, at which point the partially parsed arrow function
// concise body happens to be a valid expression. This is a problem
// only for arrow functions with single expression bodies, since there
// is no end token such as "}" for normal functions.
if (scanner()->location().end_pos == info->end_position()) {
// The pre-parser saw an arrow function here, so the full parser
// must produce a FunctionLiteral.
DCHECK(expression->IsFunctionLiteral());
result = expression->AsFunctionLiteral();
} else {
ok = false;
}
}
}
} else if (IsDefaultConstructor(kind)) {
DCHECK_EQ(scope(), outer);
result = DefaultConstructor(raw_name, IsDerivedConstructor(kind),
info->start_position(), info->end_position());
} else {
ZonePtrList<const AstRawString>* arguments_for_wrapped_function =
info->is_wrapped_as_function()
? PrepareWrappedArguments(isolate, info, zone())
: nullptr;
result = ParseFunctionLiteral(
raw_name, Scanner::Location::invalid(), kSkipFunctionNameCheck, kind,
kNoSourcePosition, function_type, info->language_mode(),
arguments_for_wrapped_function, &ok);
}
if (ok) {
result->set_requires_instance_fields_initializer(
info->requires_instance_fields_initializer());
}
// Make sure the results agree.
DCHECK(ok == (result != nullptr));
}
// Make sure the target stack is empty.
DCHECK_NULL(target_stack_);
DCHECK_IMPLIES(result,
info->function_literal_id() == result->function_literal_id());
return result;
}
Statement* Parser::ParseModuleItem(bool* ok) {
// ecma262/#prod-ModuleItem
// ModuleItem :
// ImportDeclaration
// ExportDeclaration
// StatementListItem
Token::Value next = peek();
if (next == Token::EXPORT) {
return ParseExportDeclaration(ok);
}
if (next == Token::IMPORT) {
// We must be careful not to parse a dynamic import expression as an import
// declaration. Same for import.meta expressions.
Token::Value peek_ahead = PeekAhead();
if ((!allow_harmony_dynamic_import() || peek_ahead != Token::LPAREN) &&
(!allow_harmony_import_meta() || peek_ahead != Token::PERIOD)) {
ParseImportDeclaration(CHECK_OK);
return factory()->NewEmptyStatement(kNoSourcePosition);
}
}
return ParseStatementListItem(ok);
}
void Parser::ParseModuleItemList(ZonePtrList<Statement>* body, bool* ok) {
// ecma262/#prod-Module
// Module :
// ModuleBody?
//
// ecma262/#prod-ModuleItemList
// ModuleBody :
// ModuleItem*
DCHECK(scope()->is_module_scope());
while (peek() != Token::EOS) {
Statement* stat = ParseModuleItem(CHECK_OK_VOID);
if (stat && !stat->IsEmpty()) {
body->Add(stat, zone());
}
}
}
const AstRawString* Parser::ParseModuleSpecifier(bool* ok) {
// ModuleSpecifier :
// StringLiteral
Expect(Token::STRING, CHECK_OK);
return GetSymbol();
}
ZoneChunkList<Parser::ExportClauseData>* Parser::ParseExportClause(
Scanner::Location* reserved_loc, bool* ok) {
// ExportClause :
// '{' '}'
// '{' ExportsList '}'
// '{' ExportsList ',' '}'
//
// ExportsList :
// ExportSpecifier
// ExportsList ',' ExportSpecifier
//
// ExportSpecifier :
// IdentifierName
// IdentifierName 'as' IdentifierName
ZoneChunkList<ExportClauseData>* export_data =
new (zone()) ZoneChunkList<ExportClauseData>(zone());
Expect(Token::LBRACE, CHECK_OK);
Token::Value name_tok;
while ((name_tok = peek()) != Token::RBRACE) {
// Keep track of the first reserved word encountered in case our
// caller needs to report an error.
if (!reserved_loc->IsValid() &&
!Token::IsIdentifier(name_tok, LanguageMode::kStrict, false,
parsing_module_)) {
*reserved_loc = scanner()->location();
}
const AstRawString* local_name = ParseIdentifierName(CHECK_OK);
const AstRawString* export_name = nullptr;
Scanner::Location location = scanner()->location();
if (CheckContextualKeyword(Token::AS)) {
export_name = ParseIdentifierName(CHECK_OK);
// Set the location to the whole "a as b" string, so that it makes sense
// both for errors due to "a" and for errors due to "b".
location.end_pos = scanner()->location().end_pos;
}
if (export_name == nullptr) {
export_name = local_name;
}
export_data->push_back({export_name, local_name, location});
if (peek() == Token::RBRACE) break;
Expect(Token::COMMA, CHECK_OK);
}
Expect(Token::RBRACE, CHECK_OK);
return export_data;
}
ZonePtrList<const Parser::NamedImport>* Parser::ParseNamedImports(int pos,
bool* ok) {
// NamedImports :
// '{' '}'
// '{' ImportsList '}'
// '{' ImportsList ',' '}'
//
// ImportsList :
// ImportSpecifier
// ImportsList ',' ImportSpecifier
//
// ImportSpecifier :
// BindingIdentifier
// IdentifierName 'as' BindingIdentifier
Expect(Token::LBRACE, CHECK_OK);
auto result = new (zone()) ZonePtrList<const NamedImport>(1, zone());
while (peek() != Token::RBRACE) {
const AstRawString* import_name = ParseIdentifierName(CHECK_OK);
const AstRawString* local_name = import_name;
Scanner::Location location = scanner()->location();
// In the presence of 'as', the left-side of the 'as' can
// be any IdentifierName. But without 'as', it must be a valid
// BindingIdentifier.
if (CheckContextualKeyword(Token::AS)) {
local_name = ParseIdentifierName(CHECK_OK);
}
if (!Token::IsIdentifier(scanner()->current_token(), LanguageMode::kStrict,
false, parsing_module_)) {
*ok = false;
ReportMessage(MessageTemplate::kUnexpectedReserved);
return nullptr;
} else if (IsEvalOrArguments(local_name)) {
*ok = false;
ReportMessage(MessageTemplate::kStrictEvalArguments);
return nullptr;
}
DeclareVariable(local_name, VariableMode::kConst, kNeedsInitialization,
position(), CHECK_OK);
NamedImport* import =
new (zone()) NamedImport(import_name, local_name, location);
result->Add(import, zone());
if (peek() == Token::RBRACE) break;
Expect(Token::COMMA, CHECK_OK);
}
Expect(Token::RBRACE, CHECK_OK);
return result;
}
void Parser::ParseImportDeclaration(bool* ok) {
// ImportDeclaration :
// 'import' ImportClause 'from' ModuleSpecifier ';'
// 'import' ModuleSpecifier ';'
//
// ImportClause :
// ImportedDefaultBinding
// NameSpaceImport
// NamedImports
// ImportedDefaultBinding ',' NameSpaceImport
// ImportedDefaultBinding ',' NamedImports
//
// NameSpaceImport :
// '*' 'as' ImportedBinding
int pos = peek_position();
Expect(Token::IMPORT, CHECK_OK_VOID);
Token::Value tok = peek();
// 'import' ModuleSpecifier ';'
if (tok == Token::STRING) {
Scanner::Location specifier_loc = scanner()->peek_location();
const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK_VOID);
ExpectSemicolon(CHECK_OK_VOID);
module()->AddEmptyImport(module_specifier, specifier_loc);
return;
}
// Parse ImportedDefaultBinding if present.
const AstRawString* import_default_binding = nullptr;
Scanner::Location import_default_binding_loc;
if (tok != Token::MUL && tok != Token::LBRACE) {
import_default_binding =
ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK_VOID);
import_default_binding_loc = scanner()->location();
DeclareVariable(import_default_binding, VariableMode::kConst,
kNeedsInitialization, pos, CHECK_OK_VOID);
}
// Parse NameSpaceImport or NamedImports if present.
const AstRawString* module_namespace_binding = nullptr;
Scanner::Location module_namespace_binding_loc;
const ZonePtrList<const NamedImport>* named_imports = nullptr;
if (import_default_binding == nullptr || Check(Token::COMMA)) {
switch (peek()) {
case Token::MUL: {
Consume(Token::MUL);
ExpectContextualKeyword(Token::AS, CHECK_OK_VOID);
module_namespace_binding =
ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK_VOID);
module_namespace_binding_loc = scanner()->location();
DeclareVariable(module_namespace_binding, VariableMode::kConst,
kCreatedInitialized, pos, CHECK_OK_VOID);
break;
}
case Token::LBRACE:
named_imports = ParseNamedImports(pos, CHECK_OK_VOID);
break;
default:
*ok = false;
ReportUnexpectedToken(scanner()->current_token());
return;
}
}
ExpectContextualKeyword(Token::FROM, CHECK_OK_VOID);
Scanner::Location specifier_loc = scanner()->peek_location();
const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK_VOID);
ExpectSemicolon(CHECK_OK_VOID);
// Now that we have all the information, we can make the appropriate
// declarations.
// TODO(neis): Would prefer to call DeclareVariable for each case below rather
// than above and in ParseNamedImports, but then a possible error message
// would point to the wrong location. Maybe have a DeclareAt version of
// Declare that takes a location?
if (module_namespace_binding != nullptr) {
module()->AddStarImport(module_namespace_binding, module_specifier,
module_namespace_binding_loc, specifier_loc,
zone());
}
if (import_default_binding != nullptr) {
module()->AddImport(ast_value_factory()->default_string(),
import_default_binding, module_specifier,
import_default_binding_loc, specifier_loc, zone());
}
if (named_imports != nullptr) {
if (named_imports->length() == 0) {
module()->AddEmptyImport(module_specifier, specifier_loc);
} else {
for (int i = 0; i < named_imports->length(); ++i) {
const NamedImport* import = named_imports->at(i);
module()->AddImport(import->import_name, import->local_name,
module_specifier, import->location, specifier_loc,
zone());
}
}
}
}
Statement* Parser::ParseExportDefault(bool* ok) {
// Supports the following productions, starting after the 'default' token:
// 'export' 'default' HoistableDeclaration
// 'export' 'default' ClassDeclaration
// 'export' 'default' AssignmentExpression[In] ';'
Expect(Token::DEFAULT, CHECK_OK);
Scanner::Location default_loc = scanner()->location();
ZonePtrList<const AstRawString> local_names(1, zone());
Statement* result = nullptr;
switch (peek()) {
case Token::FUNCTION:
result = ParseHoistableDeclaration(&local_names, true, CHECK_OK);
break;
case Token::CLASS:
Consume(Token::CLASS);
result = ParseClassDeclaration(&local_names, true, CHECK_OK);
break;
case Token::ASYNC:
if (PeekAhead() == Token::FUNCTION &&
!scanner()->HasAnyLineTerminatorAfterNext()) {
Consume(Token::ASYNC);
result = ParseAsyncFunctionDeclaration(&local_names, true, CHECK_OK);
break;
}
V8_FALLTHROUGH;
default: {
int pos = position();
ExpressionClassifier classifier(this);
Expression* value = ParseAssignmentExpression(true, CHECK_OK);
ValidateExpression(CHECK_OK);
SetFunctionName(value, ast_value_factory()->default_string());
const AstRawString* local_name =
ast_value_factory()->star_default_star_string();
local_names.Add(local_name, zone());
// It's fine to declare this as VariableMode::kConst because the user has
// no way of writing to it.
Declaration* decl =
DeclareVariable(local_name, VariableMode::kConst, pos, CHECK_OK);
decl->proxy()->var()->set_initializer_position(position());
Assignment* assignment = factory()->NewAssignment(
Token::INIT, decl->proxy(), value, kNoSourcePosition);
result = IgnoreCompletion(
factory()->NewExpressionStatement(assignment, kNoSourcePosition));
ExpectSemicolon(CHECK_OK);
break;
}
}
DCHECK_EQ(local_names.length(), 1);
module()->AddExport(local_names.first(),
ast_value_factory()->default_string(), default_loc,
zone());
DCHECK_NOT_NULL(result);
return result;
}
Statement* Parser::ParseExportDeclaration(bool* ok) {
// ExportDeclaration:
// 'export' '*' 'from' ModuleSpecifier ';'
// 'export' ExportClause ('from' ModuleSpecifier)? ';'
// 'export' VariableStatement
// 'export' Declaration
// 'export' 'default' ... (handled in ParseExportDefault)
Expect(Token::EXPORT, CHECK_OK);
int pos = position();
Statement* result = nullptr;
ZonePtrList<const AstRawString> names(1, zone());
Scanner::Location loc = scanner()->peek_location();
switch (peek()) {
case Token::DEFAULT:
return ParseExportDefault(ok);
case Token::MUL: {
Consume(Token::MUL);
loc = scanner()->location();
ExpectContextualKeyword(Token::FROM, CHECK_OK);
Scanner::Location specifier_loc = scanner()->peek_location();
const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK);
ExpectSemicolon(CHECK_OK);
module()->AddStarExport(module_specifier, loc, specifier_loc, zone());
return factory()->NewEmptyStatement(pos);
}
case Token::LBRACE: {
// There are two cases here:
//
// 'export' ExportClause ';'
// and
// 'export' ExportClause FromClause ';'
//
// In the first case, the exported identifiers in ExportClause must
// not be reserved words, while in the latter they may be. We
// pass in a location that gets filled with the first reserved word
// encountered, and then throw a SyntaxError if we are in the
// non-FromClause case.
Scanner::Location reserved_loc = Scanner::Location::invalid();
ZoneChunkList<ExportClauseData>* export_data =
ParseExportClause(&reserved_loc, CHECK_OK);
const AstRawString* module_specifier = nullptr;
Scanner::Location specifier_loc;
if (CheckContextualKeyword(Token::FROM)) {
specifier_loc = scanner()->peek_location();
module_specifier = ParseModuleSpecifier(CHECK_OK);
} else if (reserved_loc.IsValid()) {
// No FromClause, so reserved words are invalid in ExportClause.
*ok = false;
ReportMessageAt(reserved_loc, MessageTemplate::kUnexpectedReserved);
return nullptr;
}
ExpectSemicolon(CHECK_OK);
if (module_specifier == nullptr) {
for (const ExportClauseData& data : *export_data) {
module()->AddExport(data.local_name, data.export_name, data.location,
zone());
}
} else if (export_data->is_empty()) {
module()->AddEmptyImport(module_specifier, specifier_loc);
} else {
for (const ExportClauseData& data : *export_data) {
module()->AddExport(data.local_name, data.export_name,
module_specifier, data.location, specifier_loc,
zone());
}
}
return factory()->NewEmptyStatement(pos);
}
case Token::FUNCTION:
result = ParseHoistableDeclaration(&names, false, CHECK_OK);
break;
case Token::CLASS:
Consume(Token::CLASS);
result = ParseClassDeclaration(&names, false, CHECK_OK);
break;
case Token::VAR:
case Token::LET:
case Token::CONST:
result = ParseVariableStatement(kStatementListItem, &names, CHECK_OK);
break;
case Token::ASYNC:
// TODO(neis): Why don't we have the same check here as in
// ParseStatementListItem?
Consume(Token::ASYNC);
result = ParseAsyncFunctionDeclaration(&names, false, CHECK_OK);
break;
default:
*ok = false;
ReportUnexpectedToken(scanner()->current_token());
return nullptr;
}
loc.end_pos = scanner()->location().end_pos;
ModuleDescriptor* descriptor = module();
for (int i = 0; i < names.length(); ++i) {
descriptor->AddExport(names[i], names[i], loc, zone());
}
DCHECK_NOT_NULL(result);
return result;
}
VariableProxy* Parser::NewUnresolved(const AstRawString* name, int begin_pos,
VariableKind kind) {
return scope()->NewUnresolved(factory(), name, begin_pos, kind);
}
VariableProxy* Parser::NewUnresolved(const AstRawString* name) {
return scope()->NewUnresolved(factory(), name, scanner()->location().beg_pos);
}
Declaration* Parser::DeclareVariable(const AstRawString* name,
VariableMode mode, int pos, bool* ok) {
return DeclareVariable(name, mode, Variable::DefaultInitializationFlag(mode),
pos, ok);
}
Declaration* Parser::DeclareVariable(const AstRawString* name,
VariableMode mode, InitializationFlag init,
int pos, bool* ok) {
DCHECK_NOT_NULL(name);
VariableProxy* proxy = factory()->NewVariableProxy(
name, NORMAL_VARIABLE, scanner()->location().beg_pos);
Declaration* declaration;
if (mode == VariableMode::kVar && !scope()->is_declaration_scope()) {
DCHECK(scope()->is_block_scope() || scope()->is_with_scope());
declaration = factory()->NewNestedVariableDeclaration(proxy, scope(), pos);
} else {
declaration = factory()->NewVariableDeclaration(proxy, pos);
}
Declare(declaration, DeclarationDescriptor::NORMAL, mode, init, ok, nullptr,
scanner()->location().end_pos);
if (!*ok) return nullptr;
return declaration;
}
Variable* Parser::Declare(Declaration* declaration,
DeclarationDescriptor::Kind declaration_kind,
VariableMode mode, InitializationFlag init, bool* ok,
Scope* scope, int var_end_pos) {
if (scope == nullptr) {
scope = this->scope();
}
bool sloppy_mode_block_scope_function_redefinition = false;
Variable* variable = scope->DeclareVariable(
declaration, mode, init, &sloppy_mode_block_scope_function_redefinition,
ok);
if (!*ok) {
// If we only have the start position of a proxy, we can't highlight the
// whole variable name. Pretend its length is 1 so that we highlight at
// least the first character.
Scanner::Location loc(declaration->proxy()->position(),
var_end_pos != kNoSourcePosition
? var_end_pos
: declaration->proxy()->position() + 1);
if (declaration_kind == DeclarationDescriptor::PARAMETER) {
ReportMessageAt(loc, MessageTemplate::kParamDupe);
} else {
ReportMessageAt(loc, MessageTemplate::kVarRedeclaration,
declaration->proxy()->raw_name());
}
return nullptr;
}
if (sloppy_mode_block_scope_function_redefinition) {
++use_counts_[v8::Isolate::kSloppyModeBlockScopedFunctionRedefinition];
}
return variable;
}
Block* Parser::BuildInitializationBlock(
DeclarationParsingResult* parsing_result,
ZonePtrList<const AstRawString>* names, bool* ok) {
Block* result = factory()->NewBlock(1, true);
for (auto declaration : parsing_result->declarations) {
DeclareAndInitializeVariables(result, &(parsing_result->descriptor),
&declaration, names, CHECK_OK);
}
return result;
}
Statement* Parser::DeclareFunction(const AstRawString* variable_name,
FunctionLiteral* function, VariableMode mode,
int pos, bool is_sloppy_block_function,
ZonePtrList<const AstRawString>* names,
bool* ok) {
VariableProxy* proxy =
factory()->NewVariableProxy(variable_name, NORMAL_VARIABLE, pos);
Declaration* declaration =
factory()->NewFunctionDeclaration(proxy, function, pos);
Declare(declaration, DeclarationDescriptor::NORMAL, mode, kCreatedInitialized,
CHECK_OK);
if (names) names->Add(variable_name, zone());
if (is_sloppy_block_function) {
SloppyBlockFunctionStatement* statement =
factory()->NewSloppyBlockFunctionStatement();
GetDeclarationScope()->DeclareSloppyBlockFunction(variable_name, scope(),
statement);
return statement;
}
return factory()->NewEmptyStatement(kNoSourcePosition);
}
Statement* Parser::DeclareClass(const AstRawString* variable_name,
Expression* value,
ZonePtrList<const AstRawString>* names,
int class_token_pos, int end_pos, bool* ok) {
Declaration* decl = DeclareVariable(variable_name, VariableMode::kLet,
class_token_pos, CHECK_OK);
decl->proxy()->var()->set_initializer_position(end_pos);
if (names) names->Add(variable_name, zone());
Assignment* assignment = factory()->NewAssignment(Token::INIT, decl->proxy(),
value, class_token_pos);
return IgnoreCompletion(
factory()->NewExpressionStatement(assignment, kNoSourcePosition));
}
Statement* Parser::DeclareNative(const AstRawString* name, int pos, bool* ok) {
// Make sure that the function containing the native declaration
// isn't lazily compiled. The extension structures are only
// accessible while parsing the first time not when reparsing
// because of lazy compilation.
GetClosureScope()->ForceEagerCompilation();
// TODO(1240846): It's weird that native function declarations are
// introduced dynamically when we meet their declarations, whereas
// other functions are set up when entering the surrounding scope.
Declaration* decl = DeclareVariable(name, VariableMode::kVar, pos, CHECK_OK);
NativeFunctionLiteral* lit =
factory()->NewNativeFunctionLiteral(name, extension_, kNoSourcePosition);
return factory()->NewExpressionStatement(
factory()->NewAssignment(Token::INIT, decl->proxy(), lit,
kNoSourcePosition),
pos);
}
void Parser::DeclareLabel(ZonePtrList<const AstRawString>** labels,
ZonePtrList<const AstRawString>** own_labels,
VariableProxy* var, bool* ok) {
DCHECK(IsIdentifier(var));
const AstRawString* label = var->raw_name();
// TODO(1240780): We don't check for redeclaration of labels
// during preparsing since keeping track of the set of active
// labels requires nontrivial changes to the way scopes are
// structured. However, these are probably changes we want to
// make later anyway so we should go back and fix this then.
if (ContainsLabel(*labels, label) || TargetStackContainsLabel(label)) {
ReportMessage(MessageTemplate::kLabelRedeclaration, label);
*ok = false;
return;
}
// Add {label} to both {labels} and {own_labels}.
if (*labels == nullptr) {
DCHECK_NULL(*own_labels);
*labels = new (zone()) ZonePtrList<const AstRawString>(1, zone());
*own_labels = new (zone()) ZonePtrList<const AstRawString>(1, zone());
} else {
if (*own_labels == nullptr) {
*own_labels = new (zone()) ZonePtrList<const AstRawString>(1, zone());
}
}
(*labels)->Add(label, zone());
(*own_labels)->Add(label, zone());
// Remove the "ghost" variable that turned out to be a label
// from the top scope. This way, we don't try to resolve it
// during the scope processing.
scope()->RemoveUnresolved(var);
}
bool Parser::ContainsLabel(ZonePtrList<const AstRawString>* labels,
const AstRawString* label) {
DCHECK_NOT_NULL(label);
if (labels != nullptr) {
for (int i = labels->length(); i-- > 0;) {
if (labels->at(i) == label) return true;
}
}
return false;
}
Block* Parser::IgnoreCompletion(Statement* statement) {
Block* block = factory()->NewBlock(1, true);
block->statements()->Add(statement, zone());
return block;
}
Expression* Parser::RewriteReturn(Expression* return_value, int pos) {
if (IsDerivedConstructor(function_state_->kind())) {
// For subclass constructors we need to return this in case of undefined;
// other primitive values trigger an exception in the ConstructStub.
//
// return expr;
//
// Is rewritten as:
//
// return (temp = expr) === undefined ? this : temp;
// temp = expr
Variable* temp = NewTemporary(ast_value_factory()->empty_string());
Assignment* assign = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(temp), return_value, pos);
// temp === undefined
Expression* is_undefined = factory()->NewCompareOperation(
Token::EQ_STRICT, assign,
factory()->NewUndefinedLiteral(kNoSourcePosition), pos);
// is_undefined ? this : temp
return_value =
factory()->NewConditional(is_undefined, ThisExpression(pos),
factory()->NewVariableProxy(temp), pos);
}
return return_value;
}
Expression* Parser::RewriteDoExpression(Block* body, int pos, bool* ok) {
Variable* result = NewTemporary(ast_value_factory()->dot_result_string());
DoExpression* expr = factory()->NewDoExpression(body, result, pos);
if (!Rewriter::Rewrite(this, GetClosureScope(), expr, ast_value_factory())) {
*ok = false;
return nullptr;
}
return expr;
}
Statement* Parser::RewriteSwitchStatement(SwitchStatement* switch_statement,
Scope* scope) {
// In order to get the CaseClauses to execute in their own lexical scope,
// but without requiring downstream code to have special scope handling
// code for switch statements, desugar into blocks as follows:
// { // To group the statements--harmless to evaluate Expression in scope
// .tag_variable = Expression;
// { // To give CaseClauses a scope
// switch (.tag_variable) { CaseClause* }
// }
// }
DCHECK_NOT_NULL(scope);
DCHECK(scope->is_block_scope());
DCHECK_GE(switch_statement->position(), scope->start_position());
DCHECK_LT(switch_statement->position(), scope->end_position());
Block* switch_block = factory()->NewBlock(2, false);
Expression* tag = switch_statement->tag();
Variable* tag_variable =
NewTemporary(ast_value_factory()->dot_switch_tag_string());
Assignment* tag_assign = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(tag_variable), tag,
tag->position());
// Wrap with IgnoreCompletion so the tag isn't returned as the completion
// value, in case the switch statements don't have a value.
Statement* tag_statement = IgnoreCompletion(
factory()->NewExpressionStatement(tag_assign, kNoSourcePosition));
switch_block->statements()->Add(tag_statement, zone());
switch_statement->set_tag(factory()->NewVariableProxy(tag_variable));
Block* cases_block = factory()->NewBlock(1, false);
cases_block->statements()->Add(switch_statement, zone());
cases_block->set_scope(scope);
switch_block->statements()->Add(cases_block, zone());
return switch_block;
}
void Parser::RewriteCatchPattern(CatchInfo* catch_info, bool* ok) {
if (catch_info->name == nullptr) {
DCHECK_NOT_NULL(catch_info->pattern);
catch_info->name = ast_value_factory()->dot_catch_string();
}
Variable* catch_variable =
catch_info->scope->DeclareLocal(catch_info->name, VariableMode::kVar);
if (catch_info->pattern != nullptr) {
DeclarationDescriptor descriptor;
descriptor.declaration_kind = DeclarationDescriptor::NORMAL;
descriptor.scope = scope();
descriptor.mode = VariableMode::kLet;
descriptor.declaration_pos = catch_info->pattern->position();
descriptor.initialization_pos = catch_info->pattern->position();
// Initializer position for variables declared by the pattern.
const int initializer_position = position();
DeclarationParsingResult::Declaration decl(
catch_info->pattern, initializer_position,
factory()->NewVariableProxy(catch_variable));
catch_info->init_block = factory()->NewBlock(8, true);
DeclareAndInitializeVariables(catch_info->init_block, &descriptor, &decl,
&catch_info->bound_names, ok);
} else {
catch_info->bound_names.Add(catch_info->name, zone());
}
}
void Parser::ValidateCatchBlock(const CatchInfo& catch_info, bool* ok) {
// Check for `catch(e) { let e; }` and similar errors.
Scope* inner_block_scope = catch_info.inner_block->scope();
if (inner_block_scope != nullptr) {
Declaration* decl = inner_block_scope->CheckLexDeclarationsConflictingWith(
catch_info.bound_names);
if (decl != nullptr) {
const AstRawString* name = decl->proxy()->raw_name();
int position = decl->proxy()->position();
Scanner::Location location =
position == kNoSourcePosition
? Scanner::Location::invalid()
: Scanner::Location(position, position + 1);
ReportMessageAt(location, MessageTemplate::kVarRedeclaration, name);
*ok = false;
}
}
}
Statement* Parser::RewriteTryStatement(Block* try_block, Block* catch_block,
const SourceRange& catch_range,
Block* finally_block,
const SourceRange& finally_range,
const CatchInfo& catch_info, int pos) {
// Simplify the AST nodes by converting:
// 'try B0 catch B1 finally B2'
// to:
// 'try { try B0 catch B1 } finally B2'
if (catch_block != nullptr && finally_block != nullptr) {
// If we have both, create an inner try/catch.
TryCatchStatement* statement;
statement = factory()->NewTryCatchStatement(try_block, catch_info.scope,
catch_block, kNoSourcePosition);
RecordTryCatchStatementSourceRange(statement, catch_range);
try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(statement, zone());
catch_block = nullptr; // Clear to indicate it's been handled.
}
if (catch_block != nullptr) {
DCHECK_NULL(finally_block);
TryCatchStatement* stmt = factory()->NewTryCatchStatement(
try_block, catch_info.scope, catch_block, pos);
RecordTryCatchStatementSourceRange(stmt, catch_range);
return stmt;
} else {
DCHECK_NOT_NULL(finally_block);
TryFinallyStatement* stmt =
factory()->NewTryFinallyStatement(try_block, finally_block, pos);
RecordTryFinallyStatementSourceRange(stmt, finally_range);
return stmt;
}
}
void Parser::ParseAndRewriteGeneratorFunctionBody(int pos, FunctionKind kind,
ZonePtrList<Statement>* body,
bool* ok) {
// For ES6 Generators, we just prepend the initial yield.
Expression* initial_yield = BuildInitialYield(pos, kind);
body->Add(factory()->NewExpressionStatement(initial_yield, kNoSourcePosition),
zone());
ParseStatementList(body, Token::RBRACE, ok);
}
void Parser::ParseAndRewriteAsyncGeneratorFunctionBody(
int pos, FunctionKind kind, ZonePtrList<Statement>* body, bool* ok) {
// For ES2017 Async Generators, we produce:
//
// try {
// InitialYield;
// ...body...;
// return undefined; // See comment below
// } 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.
DCHECK(IsAsyncGeneratorFunction(kind));
Block* try_block = factory()->NewBlock(3, false);
Expression* initial_yield = BuildInitialYield(pos, kind);
try_block->statements()->Add(
factory()->NewExpressionStatement(initial_yield, kNoSourcePosition),
zone());
ParseStatementList(try_block->statements(), Token::RBRACE, ok);
if (!*ok) return;
// Don't create iterator result for async generators, as the resume methods
// will create it.
// TODO(leszeks): This will create another suspend point, which is unnecessary
// if there is already an unconditional return in the body.
Statement* final_return = BuildReturnStatement(
factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition);
try_block->statements()->Add(final_return, zone());
// For AsyncGenerators, a top-level catch block will reject the Promise.
Scope* catch_scope = NewHiddenCatchScope();
ZonePtrList<Expression>* reject_args =
new (zone()) ZonePtrList<Expression>(2, zone());
reject_args->Add(factory()->NewVariableProxy(
function_state_->scope()->generator_object_var()),
zone());
reject_args->Add(factory()->NewVariableProxy(catch_scope->catch_variable()),
zone());
Expression* reject_call = factory()->NewCallRuntime(
Runtime::kInlineAsyncGeneratorReject, reject_args, kNoSourcePosition);
Block* catch_block = IgnoreCompletion(
factory()->NewReturnStatement(reject_call, kNoSourcePosition));
TryStatement* try_catch = factory()->NewTryCatchStatementForAsyncAwait(
try_block, catch_scope, catch_block, kNoSourcePosition);
try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(try_catch, zone());
Block* finally_block = factory()->NewBlock(1, false);
ZonePtrList<Expression>* close_args =
new (zone()) ZonePtrList<Expression>(1, zone());
VariableProxy* call_proxy = factory()->NewVariableProxy(
function_state_->scope()->generator_object_var());
close_args->Add(call_proxy, zone());
Expression* close_call = factory()->NewCallRuntime(
Runtime::kInlineGeneratorClose, close_args, kNoSourcePosition);
finally_block->statements()->Add(
factory()->NewExpressionStatement(close_call, kNoSourcePosition), zone());
body->Add(factory()->NewTryFinallyStatement(try_block, finally_block,
kNoSourcePosition),
zone());
}
void Parser::DeclareFunctionNameVar(const AstRawString* function_name,
FunctionLiteral::FunctionType function_type,
DeclarationScope* function_scope) {
if (function_type == FunctionLiteral::kNamedExpression &&
function_scope->LookupLocal(function_name) == nullptr) {
DCHECK_EQ(function_scope, scope());
function_scope->DeclareFunctionVar(function_name);
}
}
// [if (IteratorType == kNormal)]
// !%_IsJSReceiver(result = iterator.next()) &&
// %ThrowIteratorResultNotAnObject(result)
// [else if (IteratorType == kAsync)]
// !%_IsJSReceiver(result = Await(iterator.next())) &&
// %ThrowIteratorResultNotAnObject(result)
// [endif]
Expression* Parser::BuildIteratorNextResult(VariableProxy* iterator,
VariableProxy* next,
Variable* result, IteratorType type,
int pos) {
Expression* next_property = factory()->NewResolvedProperty(iterator, next);
ZonePtrList<Expression>* next_arguments =
new (zone()) ZonePtrList<Expression>(0, zone());
Expression* next_call =
factory()->NewCall(next_property, next_arguments, kNoSourcePosition);
if (type == IteratorType::kAsync) {
function_state_->AddSuspend();
next_call = factory()->NewAwait(next_call, pos);
}
Expression* result_proxy = factory()->NewVariableProxy(result);
Expression* left =
factory()->NewAssignment(Token::ASSIGN, result_proxy, next_call, pos);
// %_IsJSReceiver(...)
ZonePtrList<Expression>* is_spec_object_args =
new (zone()) ZonePtrList<Expression>(1, zone());
is_spec_object_args->Add(left, zone());
Expression* is_spec_object_call = factory()->NewCallRuntime(
Runtime::kInlineIsJSReceiver, is_spec_object_args, pos);
// %ThrowIteratorResultNotAnObject(result)
Expression* result_proxy_again = factory()->NewVariableProxy(result);
ZonePtrList<Expression>* throw_arguments =
new (zone()) ZonePtrList<Expression>(1, zone());
throw_arguments->Add(result_proxy_again, zone());
Expression* throw_call = factory()->NewCallRuntime(
Runtime::kThrowIteratorResultNotAnObject, throw_arguments, pos);
return factory()->NewBinaryOperation(
Token::AND,
factory()->NewUnaryOperation(Token::NOT, is_spec_object_call, pos),
throw_call, pos);
}
Statement* Parser::InitializeForEachStatement(ForEachStatement* stmt,
Expression* each,
Expression* subject,
Statement* body) {
ForOfStatement* for_of = stmt->AsForOfStatement();
if (for_of != nullptr) {
const bool finalize = true;
return InitializeForOfStatement(for_of, each, subject, body, finalize,
IteratorType::kNormal, each->position());
} else {
if (each->IsArrayLiteral() || each->IsObjectLiteral()) {
Variable* temp = NewTemporary(ast_value_factory()->empty_string());
VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
Expression* assign_each =
RewriteDestructuringAssignment(factory()->NewAssignment(
Token::ASSIGN, each, temp_proxy, kNoSourcePosition));
auto block = factory()->NewBlock(2, false);
block->statements()->Add(
factory()->NewExpressionStatement(assign_each, kNoSourcePosition),
zone());
block->statements()->Add(body, zone());
body = block;
each = factory()->NewVariableProxy(temp);
}
MarkExpressionAsAssigned(each);
stmt->AsForInStatement()->Initialize(each, subject, body);
}
return stmt;
}
// Special case for legacy for
//
// for (var x = initializer in enumerable) body
//
// An initialization block of the form
//
// {
// x = initializer;
// }
//
// is returned in this case. It has reserved space for two statements,
// so that (later on during parsing), the equivalent of
//
// for (x in enumerable) body
//
// is added as a second statement to it.
Block* Parser::RewriteForVarInLegacy(const ForInfo& for_info) {
const DeclarationParsingResult::Declaration& decl =
for_info.parsing_result.declarations[0];
if (!IsLexicalVariableMode(for_info.parsing_result.descriptor.mode) &&
decl.pattern->IsVariableProxy() && decl.initializer != nullptr) {
++use_counts_[v8::Isolate::kForInInitializer];
const AstRawString* name = decl.pattern->AsVariableProxy()->raw_name();
VariableProxy* single_var = NewUnresolved(name);
Block* init_block = factory()->NewBlock(2, true);
init_block->statements()->Add(
factory()->NewExpressionStatement(
factory()->NewAssignment(Token::ASSIGN, single_var,
decl.initializer, kNoSourcePosition),
kNoSourcePosition),
zone());
return init_block;
}
return nullptr;
}
// Rewrite a for-in/of statement of the form
//
// for (let/const/var x in/of e) b
//
// into
//
// {
// var temp;
// for (temp in/of e) {
// let/const/var x = temp;
// b;
// }
// let x; // for TDZ
// }
void Parser::DesugarBindingInForEachStatement(ForInfo* for_info,
Block** body_block,
Expression** each_variable,
bool* ok) {
DCHECK_EQ(1, for_info->parsing_result.declarations.size());
DeclarationParsingResult::Declaration& decl =
for_info->parsing_result.declarations[0];
Variable* temp = NewTemporary(ast_value_factory()->dot_for_string());
auto each_initialization_block = factory()->NewBlock(1, true);
{
auto descriptor = for_info->parsing_result.descriptor;
descriptor.declaration_pos = kNoSourcePosition;
descriptor.initialization_pos = kNoSourcePosition;
descriptor.scope = scope();
decl.initializer = factory()->NewVariableProxy(temp);
bool is_for_var_of =
for_info->mode == ForEachStatement::ITERATE &&
for_info->parsing_result.descriptor.mode == VariableMode::kVar;
bool collect_names =
IsLexicalVariableMode(for_info->parsing_result.descriptor.mode) ||
is_for_var_of;
DeclareAndInitializeVariables(
each_initialization_block, &descriptor, &decl,
collect_names ? &for_info->bound_names : nullptr, CHECK_OK_VOID);
// Annex B.3.5 prohibits the form
// `try {} catch(e) { for (var e of {}); }`
// So if we are parsing a statement like `for (var ... of ...)`
// we need to walk up the scope chain and look for catch scopes
// which have a simple binding, then compare their binding against
// all of the names declared in the init of the for-of we're
// parsing.
if (is_for_var_of) {
Scope* catch_scope = scope();
while (catch_scope != nullptr && !catch_scope->is_declaration_scope()) {
if (catch_scope->is_catch_scope()) {
auto name = catch_scope->catch_variable()->raw_name();
// If it's a simple binding and the name is declared in the for loop.
if (name != ast_value_factory()->dot_catch_string() &&
for_info->bound_names.Contains(name)) {
ReportMessageAt(for_info->parsing_result.bindings_loc,
MessageTemplate::kVarRedeclaration, name);
*ok = false;
return;
}
}
catch_scope = catch_scope->outer_scope();
}
}
}
*body_block = factory()->NewBlock(3, false);
(*body_block)->statements()->Add(each_initialization_block, zone());
*each_variable = factory()->NewVariableProxy(temp, for_info->position);
}
// Create a TDZ for any lexically-bound names in for in/of statements.
Block* Parser::CreateForEachStatementTDZ(Block* init_block,
const ForInfo& for_info, bool* ok) {
if (IsLexicalVariableMode(for_info.parsing_result.descriptor.mode)) {
DCHECK_NULL(init_block);
init_block = factory()->NewBlock(1, false);
for (int i = 0; i < for_info.bound_names.length(); ++i) {
// TODO(adamk): This needs to be some sort of special
// INTERNAL variable that's invisible to the debugger
// but visible to everything else.
Declaration* tdz_decl =
DeclareVariable(for_info.bound_names[i], VariableMode::kLet,
kNoSourcePosition, CHECK_OK);
tdz_decl->proxy()->var()->set_initializer_position(position());
}
}
return init_block;
}
Statement* Parser::InitializeForOfStatement(
ForOfStatement* for_of, Expression* each, Expression* iterable,
Statement* body, bool finalize, IteratorType type, int next_result_pos) {
// Create the auxiliary expressions needed for iterating over the iterable,
// and initialize the given ForOfStatement with them.
// If finalize is true, also instrument the loop with code that performs the
// proper ES6 iterator finalization. In that case, the result is not
// immediately a ForOfStatement.
const int nopos = kNoSourcePosition;
auto avfactory = ast_value_factory();
Variable* iterator = NewTemporary(avfactory->dot_iterator_string());
Variable* next = NewTemporary(avfactory->empty_string());
Variable* result = NewTemporary(avfactory->dot_result_string());
Variable* completion = NewTemporary(avfactory->empty_string());
// iterator = GetIterator(iterable, type)
Expression* assign_iterator;
{
assign_iterator = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(iterator),
factory()->NewGetIterator(iterable, type, iterable->position()),
iterable->position());
}
Expression* assign_next;
{
assign_next = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(next),
factory()->NewProperty(factory()->NewVariableProxy(iterator),
factory()->NewStringLiteral(
avfactory->next_string(), kNoSourcePosition),
kNoSourcePosition),
kNoSourcePosition);
}
// [if (IteratorType == kNormal)]
// !%_IsJSReceiver(result = iterator.next()) &&
// %ThrowIteratorResultNotAnObject(result)
// [else if (IteratorType == kAsync)]
// !%_IsJSReceiver(result = Await(iterator.next())) &&
// %ThrowIteratorResultNotAnObject(result)
// [endif]
Expression* next_result;
{
VariableProxy* iterator_proxy = factory()->NewVariableProxy(iterator);
VariableProxy* next_proxy = factory()->NewVariableProxy(next);
next_result = BuildIteratorNextResult(iterator_proxy, next_proxy, result,
type, next_result_pos);
}
// result.done
Expression* result_done;
{
Expression* done_literal = factory()->NewStringLiteral(
ast_value_factory()->done_string(), kNoSourcePosition);
Expression* result_proxy = factory()->NewVariableProxy(result);
result_done =
factory()->NewProperty(result_proxy, done_literal, kNoSourcePosition);
}
// result.value
Expression* result_value;
{
Expression* value_literal =
factory()->NewStringLiteral(avfactory->value_string(), nopos);
Expression* result_proxy = factory()->NewVariableProxy(result);
result_value = factory()->NewProperty(result_proxy, value_literal, nopos);
}
// {{tmp = #result_value, completion = kAbruptCompletion, tmp}}
// Expression* result_value (gets overwritten)
if (finalize) {
Variable* tmp = NewTemporary(avfactory->empty_string());
Expression* save_result = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(tmp), result_value, nopos);
Expression* set_completion_abrupt = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(completion),
factory()->NewSmiLiteral(Parser::kAbruptCompletion, nopos), nopos);
result_value = factory()->NewBinaryOperation(Token::COMMA, save_result,
set_completion_abrupt, nopos);
result_value = factory()->NewBinaryOperation(
Token::COMMA, result_value, factory()->NewVariableProxy(tmp), nopos);
}
// each = #result_value;
Expression* assign_each;
{
assign_each =
factory()->NewAssignment(Token::ASSIGN, each, result_value, nopos);
if (each->IsArrayLiteral() || each->IsObjectLiteral()) {
assign_each = RewriteDestructuringAssignment(assign_each->AsAssignment());
}
}
// {{completion = kNormalCompletion;}}
Statement* set_completion_normal;
if (finalize) {
Expression* proxy = factory()->NewVariableProxy(completion);
Expression* assignment = factory()->NewAssignment(
Token::ASSIGN, proxy,
factory()->NewSmiLiteral(Parser::kNormalCompletion, nopos), nopos);
set_completion_normal =
IgnoreCompletion(factory()->NewExpressionStatement(assignment, nopos));
}
// { #loop-body; #set_completion_normal }
// Statement* body (gets overwritten)
if (finalize) {
Block* block = factory()->NewBlock(2, false);
block->statements()->Add(body, zone());
block->statements()->Add(set_completion_normal, zone());
body = block;
}
for_of->Initialize(body, iterator, assign_iterator, assign_next, next_result,
result_done, assign_each);
return finalize ? FinalizeForOfStatement(for_of, completion, type, nopos)
: for_of;
}
Statement* Parser::DesugarLexicalBindingsInForStatement(
ForStatement* loop, Statement* init, Expression* cond, Statement* next,
Statement* body, Scope* inner_scope, const ForInfo& for_info, bool* ok) {
// ES6 13.7.4.8 specifies that on each loop iteration the let variables are
// copied into a new environment. Moreover, the "next" statement must be
// evaluated not in the environment of the just completed iteration but in
// that of the upcoming one. We achieve this with the following desugaring.
// Extra care is needed to preserve the completion value of the original loop.
//
// We are given a for statement of the form
//
// labels: for (let/const x = i; cond; next) body
//
// and rewrite it as follows. Here we write {{ ... }} for init-blocks, ie.,
// blocks whose ignore_completion_value_ flag is set.
//
// {
// let/const x = i;
// temp_x = x;
// first = 1;
// undefined;
// outer: for (;;) {
// let/const x = temp_x;
// {{ if (first == 1) {
// first = 0;
// } else {
// next;
// }
// flag = 1;
// if (!cond) break;
// }}
// labels: for (; flag == 1; flag = 0, temp_x = x) {
// body
// }
// {{ if (flag == 1) // Body used break.
// break;
// }}
// }
// }
DCHECK_GT(for_info.bound_names.length(), 0);
ZonePtrList<Variable> temps(for_info.bound_names.length(), zone());
Block* outer_block =
factory()->NewBlock(for_info.bound_names.length() + 4, false);
// Add statement: let/const x = i.
outer_block->statements()->Add(init, zone());
const AstRawString* temp_name = ast_value_factory()->dot_for_string();
// For each lexical variable x:
// make statement: temp_x = x.
for (int i = 0; i < for_info.bound_names.length(); i++) {
VariableProxy* proxy = NewUnresolved(for_info.bound_names[i]);
Variable* temp = NewTemporary(temp_name);
VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
Assignment* assignment = factory()->NewAssignment(Token::ASSIGN, temp_proxy,
proxy, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
outer_block->statements()->Add(assignment_statement, zone());
temps.Add(temp, zone());
}
Variable* first = nullptr;
// Make statement: first = 1.
if (next) {
first = NewTemporary(temp_name);
VariableProxy* first_proxy = factory()->NewVariableProxy(first);
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, first_proxy, const1, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
outer_block->statements()->Add(assignment_statement, zone());
}
// make statement: undefined;
outer_block->statements()->Add(
factory()->NewExpressionStatement(
factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition),
zone());
// Make statement: outer: for (;;)
// Note that we don't actually create the label, or set this loop up as an
// explicit break target, instead handing it directly to those nodes that
// need to know about it. This should be safe because we don't run any code
// in this function that looks up break targets.
ForStatement* outer_loop =
factory()->NewForStatement(nullptr, nullptr, kNoSourcePosition);
outer_block->statements()->Add(outer_loop, zone());
outer_block->set_scope(scope());
Block* inner_block = factory()->NewBlock(3, false);
{
BlockState block_state(&scope_, inner_scope);
Block* ignore_completion_block =
factory()->NewBlock(for_info.bound_names.length() + 3, true);
ZonePtrList<Variable> inner_vars(for_info.bound_names.length(), zone());
// For each let variable x:
// make statement: let/const x = temp_x.
for (int i = 0; i < for_info.bound_names.length(); i++) {
Declaration* decl = DeclareVariable(
for_info.bound_names[i], for_info.parsing_result.descriptor.mode,
kNoSourcePosition, CHECK_OK);
inner_vars.Add(decl->proxy()->var(), zone());
VariableProxy* temp_proxy = factory()->NewVariableProxy(temps.at(i));
Assignment* assignment = factory()->NewAssignment(
Token::INIT, decl->proxy(), temp_proxy, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
int declaration_pos = for_info.parsing_result.descriptor.declaration_pos;
DCHECK_NE(declaration_pos, kNoSourcePosition);
decl->proxy()->var()->set_initializer_position(declaration_pos);
ignore_completion_block->statements()->Add(assignment_statement, zone());
}
// Make statement: if (first == 1) { first = 0; } else { next; }
if (next) {
DCHECK(first);
Expression* compare = nullptr;
// Make compare expression: first == 1.
{
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
VariableProxy* first_proxy = factory()->NewVariableProxy(first);
compare = factory()->NewCompareOperation(Token::EQ, first_proxy, const1,
kNoSourcePosition);
}
Statement* clear_first = nullptr;
// Make statement: first = 0.
{
VariableProxy* first_proxy = factory()->NewVariableProxy(first);
Expression* const0 = factory()->NewSmiLiteral(0, kNoSourcePosition);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, first_proxy, const0, kNoSourcePosition);
clear_first =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
}
Statement* clear_first_or_next = factory()->NewIfStatement(
compare, clear_first, next, kNoSourcePosition);
ignore_completion_block->statements()->Add(clear_first_or_next, zone());
}
Variable* flag = NewTemporary(temp_name);
// Make statement: flag = 1.
{
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, flag_proxy, const1, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
ignore_completion_block->statements()->Add(assignment_statement, zone());
}
// Make statement: if (!cond) break.
if (cond) {
Statement* stop =
factory()->NewBreakStatement(outer_loop, kNoSourcePosition);
Statement* noop = factory()->NewEmptyStatement(kNoSourcePosition);
ignore_completion_block->statements()->Add(
factory()->NewIfStatement(cond, noop, stop, cond->position()),
zone());
}
inner_block->statements()->Add(ignore_completion_block, zone());
// Make cond expression for main loop: flag == 1.
Expression* flag_cond = nullptr;
{
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
flag_cond = factory()->NewCompareOperation(Token::EQ, flag_proxy, const1,
kNoSourcePosition);
}
// Create chain of expressions "flag = 0, temp_x = x, ..."
Statement* compound_next_statement = nullptr;
{
Expression* compound_next = nullptr;
// Make expression: flag = 0.
{
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
Expression* const0 = factory()->NewSmiLiteral(0, kNoSourcePosition);
compound_next = factory()->NewAssignment(Token::ASSIGN, flag_proxy,
const0, kNoSourcePosition);
}
// Make the comma-separated list of temp_x = x assignments.
int inner_var_proxy_pos = scanner()->location().beg_pos;
for (int i = 0; i < for_info.bound_names.length(); i++) {
VariableProxy* temp_proxy = factory()->NewVariableProxy(temps.at(i));
VariableProxy* proxy =
factory()->NewVariableProxy(inner_vars.at(i), inner_var_proxy_pos);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, temp_proxy, proxy, kNoSourcePosition);
compound_next = factory()->NewBinaryOperation(
Token::COMMA, compound_next, assignment, kNoSourcePosition);
}
compound_next_statement =
factory()->NewExpressionStatement(compound_next, kNoSourcePosition);
}
// Make statement: labels: for (; flag == 1; flag = 0, temp_x = x)
// Note that we re-use the original loop node, which retains its labels
// and ensures that any break or continue statements in body point to
// the right place.
loop->Initialize(nullptr, flag_cond, compound_next_statement, body);
inner_block->statements()->Add(loop, zone());
// Make statement: {{if (flag == 1) break;}}
{
Expression* compare = nullptr;
// Make compare expresion: flag == 1.
{
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
compare = factory()->NewCompareOperation(Token::EQ, flag_proxy, const1,
kNoSourcePosition);
}
Statement* stop =
factory()->NewBreakStatement(outer_loop, kNoSourcePosition);
Statement* empty = factory()->NewEmptyStatement(kNoSourcePosition);
Statement* if_flag_break =
factory()->NewIfStatement(compare, stop, empty, kNoSourcePosition);
inner_block->statements()->Add(IgnoreCompletion(if_flag_break), zone());
}
inner_block->set_scope(inner_scope);
}
outer_loop->Initialize(nullptr, nullptr, nullptr, inner_block);
return outer_block;
}
void Parser::AddArrowFunctionFormalParameters(
ParserFormalParameters* parameters, Expression* expr, int end_pos,
bool* ok) {
// ArrowFunctionFormals ::
// Nary(Token::COMMA, VariableProxy*, Tail)
// Binary(Token::COMMA, NonTailArrowFunctionFormals, Tail)
// Tail
// NonTailArrowFunctionFormals ::
// Binary(Token::COMMA, NonTailArrowFunctionFormals, VariableProxy)
// VariableProxy
// Tail ::
// VariableProxy
// Spread(VariableProxy)
//
// We need to visit the parameters in left-to-right order
//
// For the Nary case, we simply visit the parameters in a loop.
if (expr->IsNaryOperation()) {
NaryOperation* nary = expr->AsNaryOperation();
// The classifier has already run, so we know that the expression is a valid
// arrow function formals production.
DCHECK_EQ(nary->op(), Token::COMMA);
// Each op position is the end position of the *previous* expr, with the
// second (i.e. first "subsequent") op position being the end position of
// the first child expression.
Expression* next = nary->first();
for (size_t i = 0; i < nary->subsequent_length(); ++i) {
AddArrowFunctionFormalParameters(
parameters, next, nary->subsequent_op_position(i), CHECK_OK_VOID);
next = nary->subsequent(i);
}
AddArrowFunctionFormalParameters(parameters, next, end_pos, CHECK_OK_VOID);
return;
}
// For the binary case, we recurse on the left-hand side of binary comma
// expressions.
if (expr->IsBinaryOperation()) {
BinaryOperation* binop = expr->AsBinaryOperation();
// The classifier has already run, so we know that the expression is a valid
// arrow function formals production.
DCHECK_EQ(binop->op(), Token::COMMA);
Expression* left = binop->left();
Expression* right = binop->right();
int comma_pos = binop->position();
AddArrowFunctionFormalParameters(parameters, left, comma_pos,
CHECK_OK_VOID);
// LHS of comma expression should be unparenthesized.
expr = right;
}
// Only the right-most expression may be a rest parameter.
DCHECK(!parameters->has_rest);
bool is_rest = expr->IsSpread();
if (is_rest) {
expr = expr->AsSpread()->expression();
parameters->has_rest = true;
}
DCHECK_IMPLIES(parameters->is_simple, !is_rest);
DCHECK_IMPLIES(parameters->is_simple, expr->IsVariableProxy());
Expression* initializer = nullptr;
if (expr->IsAssignment()) {
if (expr->IsRewritableExpression()) {
// This expression was parsed as a possible destructuring assignment.
// Mark it as already-rewritten to avoid an unnecessary visit later.
expr->AsRewritableExpression()->set_rewritten();
}
Assignment* assignment = expr->AsAssignment();
DCHECK(!assignment->IsCompoundAssignment());
initializer = assignment->value();
expr = assignment->target();
}
AddFormalParameter(parameters, expr, initializer,
end_pos, is_rest);
}
void Parser::DeclareArrowFunctionFormalParameters(
ParserFormalParameters* parameters, Expression* expr,
const Scanner::Location& params_loc, Scanner::Location* duplicate_loc,
bool* ok) {
if (expr->IsEmptyParentheses()) return;
AddArrowFunctionFormalParameters(parameters, expr, params_loc.end_pos,
CHECK_OK_VOID);
if (parameters->arity > Code::kMaxArguments) {
ReportMessageAt(params_loc, MessageTemplate::kMalformedArrowFunParamList);
*ok = false;
return;
}
bool has_duplicate = false;
DeclareFormalParameters(parameters->scope, parameters->params,
parameters->is_simple, &has_duplicate);
if (has_duplicate) {
*duplicate_loc = scanner()->location();
}
DCHECK_EQ(parameters->is_simple, parameters->scope->has_simple_parameters());
}
void Parser::PrepareGeneratorVariables() {
// Calling a generator returns a generator object. That object is stored
// in a temporary variable, a definition that is used by "yield"
// expressions.
function_state_->scope()->DeclareGeneratorObjectVar(
ast_value_factory()->dot_generator_object_string());
}
FunctionLiteral* Parser::ParseFunctionLiteral(
const AstRawString* function_name, Scanner::Location function_name_location,
FunctionNameValidity function_name_validity, FunctionKind kind,
int function_token_pos, FunctionLiteral::FunctionType function_type,
LanguageMode language_mode,
ZonePtrList<const AstRawString>* arguments_for_wrapped_function, bool* ok) {
// Function ::
// '(' FormalParameterList? ')' '{' FunctionBody '}'
//
// Getter ::
// '(' ')' '{' FunctionBody '}'
//
// Setter ::
// '(' PropertySetParameterList ')' '{' FunctionBody '}'
bool is_wrapped = function_type == FunctionLiteral::kWrapped;
DCHECK_EQ(is_wrapped, arguments_for_wrapped_function != nullptr);
int pos = function_token_pos == kNoSourcePosition ? peek_position()
: function_token_pos;
DCHECK_NE(kNoSourcePosition, pos);
// Anonymous functions were passed either the empty symbol or a null
// handle as the function name. Remember if we were passed a non-empty
// handle to decide whether to invoke function name inference.
bool should_infer_name = function_name == nullptr;
// We want a non-null handle as the function name by default. We will handle
// the "function does not have a shared name" case later.
if (should_infer_name) {
function_name = ast_value_factory()->empty_string();
}
FunctionLiteral::EagerCompileHint eager_compile_hint =
function_state_->next_function_is_likely_called() || is_wrapped
? FunctionLiteral::kShouldEagerCompile
: default_eager_compile_hint();
// Determine if the function can be parsed lazily. Lazy parsing is
// different from lazy compilation; we need to parse more eagerly than we
// compile.
// We can only parse lazily if we also compile lazily. The heuristics for lazy
// compilation are:
// - It must not have been prohibited by the caller to Parse (some callers
// need a full AST).
// - The outer scope must allow lazy compilation of inner functions.
// - The function mustn't be a function expression with an open parenthesis
// before; we consider that a hint that the function will be called
// immediately, and it would be a waste of time to make it lazily
// compiled.
// These are all things we can know at this point, without looking at the
// function itself.
// We separate between lazy parsing top level functions and lazy parsing inner
// functions, because the latter needs to do more work. In particular, we need
// to track unresolved variables to distinguish between these cases:
// (function foo() {
// bar = function() { return 1; }
// })();
// and
// (function foo() {
// var a = 1;