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chromium / v8 / v8 / refs/heads/main / . / src / debug / liveedit.cc
blob: e31d7850d4670f92619ae390ac536557ae7e54e1 [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/debug/liveedit.h"
#include "src/api/api-inl.h"
#include "src/ast/ast-traversal-visitor.h"
#include "src/ast/ast.h"
#include "src/ast/scopes.h"
#include "src/codegen/compilation-cache.h"
#include "src/codegen/compiler.h"
#include "src/codegen/source-position-table.h"
#include "src/common/globals.h"
#include "src/debug/debug-interface.h"
#include "src/debug/debug-stack-trace-iterator.h"
#include "src/debug/debug.h"
#include "src/debug/liveedit-diff.h"
#include "src/execution/frames-inl.h"
#include "src/execution/v8threads.h"
#include "src/logging/log.h"
#include "src/objects/js-generator-inl.h"
#include "src/objects/js-objects.h"
#include "src/objects/objects-inl.h"
#include "src/parsing/parse-info.h"
#include "src/parsing/parsing.h"
namespace v8 {
namespace internal {
namespace {
bool CompareSubstrings(Handle<String> s1, int pos1, Handle<String> s2, int pos2,
int len) {
for (int i = 0; i < len; i++) {
if (s1->Get(i + pos1) != s2->Get(i + pos2)) return false;
}
return true;
}
// Additional to Input interface. Lets switch Input range to subrange.
// More elegant way would be to wrap one Input as another Input object
// and translate positions there, but that would cost us additional virtual
// call per comparison.
class SubrangableInput : public Comparator::Input {
public:
virtual void SetSubrange1(int offset, int len) = 0;
virtual void SetSubrange2(int offset, int len) = 0;
};
class SubrangableOutput : public Comparator::Output {
public:
virtual void SetSubrange1(int offset, int len) = 0;
virtual void SetSubrange2(int offset, int len) = 0;
};
// Finds common prefix and suffix in input. This parts shouldn't take space in
// linear programming table. Enable subranging in input and output.
void NarrowDownInput(SubrangableInput* input, SubrangableOutput* output) {
const int len1 = input->GetLength1();
const int len2 = input->GetLength2();
int common_prefix_len;
int common_suffix_len;
{
common_prefix_len = 0;
int prefix_limit = std::min(len1, len2);
while (common_prefix_len < prefix_limit &&
input->Equals(common_prefix_len, common_prefix_len)) {
common_prefix_len++;
}
common_suffix_len = 0;
int suffix_limit =
std::min(len1 - common_prefix_len, len2 - common_prefix_len);
while (common_suffix_len < suffix_limit &&
input->Equals(len1 - common_suffix_len - 1,
len2 - common_suffix_len - 1)) {
common_suffix_len++;
}
}
if (common_prefix_len > 0 || common_suffix_len > 0) {
int new_len1 = len1 - common_suffix_len - common_prefix_len;
int new_len2 = len2 - common_suffix_len - common_prefix_len;
input->SetSubrange1(common_prefix_len, new_len1);
input->SetSubrange2(common_prefix_len, new_len2);
output->SetSubrange1(common_prefix_len, new_len1);
output->SetSubrange2(common_prefix_len, new_len2);
}
}
// Represents 2 strings as 2 arrays of tokens.
// TODO(LiveEdit): Currently it's actually an array of charactres.
// Make array of tokens instead.
class TokensCompareInput : public Comparator::Input {
public:
TokensCompareInput(Handle<String> s1, int offset1, int len1,
Handle<String> s2, int offset2, int len2)
: s1_(s1), offset1_(offset1), len1_(len1),
s2_(s2), offset2_(offset2), len2_(len2) {
}
int GetLength1() override { return len1_; }
int GetLength2() override { return len2_; }
bool Equals(int index1, int index2) override {
return s1_->Get(offset1_ + index1) == s2_->Get(offset2_ + index2);
}
private:
Handle<String> s1_;
int offset1_;
int len1_;
Handle<String> s2_;
int offset2_;
int len2_;
};
// Stores compare result in std::vector. Converts substring positions
// to absolute positions.
class TokensCompareOutput : public Comparator::Output {
public:
TokensCompareOutput(int offset1, int offset2,
std::vector<SourceChangeRange>* output)
: output_(output), offset1_(offset1), offset2_(offset2) {}
void AddChunk(int pos1, int pos2, int len1, int len2) override {
output_->emplace_back(
SourceChangeRange{pos1 + offset1_, pos1 + len1 + offset1_,
pos2 + offset2_, pos2 + offset2_ + len2});
}
private:
std::vector<SourceChangeRange>* output_;
int offset1_;
int offset2_;
};
// Wraps raw n-elements line_ends array as a list of n+1 lines. The last line
// never has terminating new line character.
class LineEndsWrapper {
public:
explicit LineEndsWrapper(Isolate* isolate, Handle<String> string)
: ends_array_(String::CalculateLineEnds(isolate, string, false)),
string_len_(string->length()) {}
int length() {
return ends_array_->length() + 1;
}
// Returns start for any line including start of the imaginary line after
// the last line.
int GetLineStart(int index) { return index == 0 ? 0 : GetLineEnd(index - 1); }
int GetLineEnd(int index) {
if (index == ends_array_->length()) {
// End of the last line is always an end of the whole string.
// If the string ends with a new line character, the last line is an
// empty string after this character.
return string_len_;
} else {
return GetPosAfterNewLine(index);
}
}
private:
Handle<FixedArray> ends_array_;
int string_len_;
int GetPosAfterNewLine(int index) {
return Smi::ToInt(ends_array_->get(index)) + 1;
}
};
// Represents 2 strings as 2 arrays of lines.
class LineArrayCompareInput : public SubrangableInput {
public:
LineArrayCompareInput(Handle<String> s1, Handle<String> s2,
LineEndsWrapper line_ends1, LineEndsWrapper line_ends2)
: s1_(s1), s2_(s2), line_ends1_(line_ends1),
line_ends2_(line_ends2),
subrange_offset1_(0), subrange_offset2_(0),
subrange_len1_(line_ends1_.length()),
subrange_len2_(line_ends2_.length()) {
}
int GetLength1() override { return subrange_len1_; }
int GetLength2() override { return subrange_len2_; }
bool Equals(int index1, int index2) override {
index1 += subrange_offset1_;
index2 += subrange_offset2_;
int line_start1 = line_ends1_.GetLineStart(index1);
int line_start2 = line_ends2_.GetLineStart(index2);
int line_end1 = line_ends1_.GetLineEnd(index1);
int line_end2 = line_ends2_.GetLineEnd(index2);
int len1 = line_end1 - line_start1;
int len2 = line_end2 - line_start2;
if (len1 != len2) {
return false;
}
return CompareSubstrings(s1_, line_start1, s2_, line_start2,
len1);
}
void SetSubrange1(int offset, int len) override {
subrange_offset1_ = offset;
subrange_len1_ = len;
}
void SetSubrange2(int offset, int len) override {
subrange_offset2_ = offset;
subrange_len2_ = len;
}
private:
Handle<String> s1_;
Handle<String> s2_;
LineEndsWrapper line_ends1_;
LineEndsWrapper line_ends2_;
int subrange_offset1_;
int subrange_offset2_;
int subrange_len1_;
int subrange_len2_;
};
// Stores compare result in std::vector. For each chunk tries to conduct
// a fine-grained nested diff token-wise.
class TokenizingLineArrayCompareOutput : public SubrangableOutput {
public:
TokenizingLineArrayCompareOutput(Isolate* isolate, LineEndsWrapper line_ends1,
LineEndsWrapper line_ends2,
Handle<String> s1, Handle<String> s2,
std::vector<SourceChangeRange>* output)
: isolate_(isolate),
line_ends1_(line_ends1),
line_ends2_(line_ends2),
s1_(s1),
s2_(s2),
subrange_offset1_(0),
subrange_offset2_(0),
output_(output) {}
void AddChunk(int line_pos1, int line_pos2, int line_len1,
int line_len2) override {
line_pos1 += subrange_offset1_;
line_pos2 += subrange_offset2_;
int char_pos1 = line_ends1_.GetLineStart(line_pos1);
int char_pos2 = line_ends2_.GetLineStart(line_pos2);
int char_len1 = line_ends1_.GetLineStart(line_pos1 + line_len1) - char_pos1;
int char_len2 = line_ends2_.GetLineStart(line_pos2 + line_len2) - char_pos2;
if (char_len1 < CHUNK_LEN_LIMIT && char_len2 < CHUNK_LEN_LIMIT) {
// Chunk is small enough to conduct a nested token-level diff.
HandleScope subTaskScope(isolate_);
TokensCompareInput tokens_input(s1_, char_pos1, char_len1,
s2_, char_pos2, char_len2);
TokensCompareOutput tokens_output(char_pos1, char_pos2, output_);
Comparator::CalculateDifference(&tokens_input, &tokens_output);
} else {
output_->emplace_back(SourceChangeRange{
char_pos1, char_pos1 + char_len1, char_pos2, char_pos2 + char_len2});
}
}
void SetSubrange1(int offset, int len) override {
subrange_offset1_ = offset;
}
void SetSubrange2(int offset, int len) override {
subrange_offset2_ = offset;
}
private:
static const int CHUNK_LEN_LIMIT = 800;
Isolate* isolate_;
LineEndsWrapper line_ends1_;
LineEndsWrapper line_ends2_;
Handle<String> s1_;
Handle<String> s2_;
int subrange_offset1_;
int subrange_offset2_;
std::vector<SourceChangeRange>* output_;
};
struct SourcePositionEvent {
enum Type { LITERAL_STARTS, LITERAL_ENDS, DIFF_STARTS, DIFF_ENDS };
int position;
Type type;
union {
FunctionLiteral* literal;
int pos_diff;
};
SourcePositionEvent(FunctionLiteral* literal, bool is_start)
: position(is_start ? literal->start_position()
: literal->end_position()),
type(is_start ? LITERAL_STARTS : LITERAL_ENDS),
literal(literal) {}
SourcePositionEvent(const SourceChangeRange& change, bool is_start)
: position(is_start ? change.start_position : change.end_position),
type(is_start ? DIFF_STARTS : DIFF_ENDS),
pos_diff((change.new_end_position - change.new_start_position) -
(change.end_position - change.start_position)) {}
static bool LessThan(const SourcePositionEvent& a,
const SourcePositionEvent& b) {
if (a.position != b.position) return a.position < b.position;
if (a.type != b.type) return a.type < b.type;
if (a.type == LITERAL_STARTS && b.type == LITERAL_STARTS) {
// If the literals start in the same position, we want the one with the
// furthest (i.e. largest) end position to be first.
if (a.literal->end_position() != b.literal->end_position()) {
return a.literal->end_position() > b.literal->end_position();
}
// If they also end in the same position, we want the first in order of
// literal ids to be first.
return a.literal->function_literal_id() <
b.literal->function_literal_id();
} else if (a.type == LITERAL_ENDS && b.type == LITERAL_ENDS) {
// If the literals end in the same position, we want the one with the
// nearest (i.e. largest) start position to be first.
if (a.literal->start_position() != b.literal->start_position()) {
return a.literal->start_position() > b.literal->start_position();
}
// If they also end in the same position, we want the last in order of
// literal ids to be first.
return a.literal->function_literal_id() >
b.literal->function_literal_id();
} else {
return a.pos_diff < b.pos_diff;
}
}
};
struct FunctionLiteralChange {
// If any of start/end position is kNoSourcePosition, this literal is
// considered damaged and will not be mapped and edited at all.
int new_start_position;
int new_end_position;
bool has_changes;
FunctionLiteral* outer_literal;
explicit FunctionLiteralChange(int new_start_position, FunctionLiteral* outer)
: new_start_position(new_start_position),
new_end_position(kNoSourcePosition),
has_changes(false),
outer_literal(outer) {}
};
using FunctionLiteralChanges =
std::unordered_map<FunctionLiteral*, FunctionLiteralChange>;
void CalculateFunctionLiteralChanges(
const std::vector<FunctionLiteral*>& literals,
const std::vector<SourceChangeRange>& diffs,
FunctionLiteralChanges* result) {
std::vector<SourcePositionEvent> events;
events.reserve(literals.size() * 2 + diffs.size() * 2);
for (FunctionLiteral* literal : literals) {
events.emplace_back(literal, true);
events.emplace_back(literal, false);
}
for (const SourceChangeRange& diff : diffs) {
events.emplace_back(diff, true);
events.emplace_back(diff, false);
}
std::sort(events.begin(), events.end(), SourcePositionEvent::LessThan);
bool inside_diff = false;
int delta = 0;
std::stack<std::pair<FunctionLiteral*, FunctionLiteralChange>> literal_stack;
for (const SourcePositionEvent& event : events) {
switch (event.type) {
case SourcePositionEvent::DIFF_ENDS:
DCHECK(inside_diff);
inside_diff = false;
delta += event.pos_diff;
break;
case SourcePositionEvent::LITERAL_ENDS: {
DCHECK_EQ(literal_stack.top().first, event.literal);
FunctionLiteralChange& change = literal_stack.top().second;
change.new_end_position = inside_diff
? kNoSourcePosition
: event.literal->end_position() + delta;
result->insert(literal_stack.top());
literal_stack.pop();
break;
}
case SourcePositionEvent::LITERAL_STARTS:
literal_stack.push(std::make_pair(
event.literal,
FunctionLiteralChange(
inside_diff ? kNoSourcePosition
: event.literal->start_position() + delta,
literal_stack.empty() ? nullptr : literal_stack.top().first)));
break;
case SourcePositionEvent::DIFF_STARTS:
DCHECK(!inside_diff);
inside_diff = true;
if (!literal_stack.empty()) {
// Note that outer literal has not necessarily changed, unless the
// diff goes past the end of this literal. In this case, we'll mark
// this function as damaged and parent as changed later in
// MapLiterals.
literal_stack.top().second.has_changes = true;
}
break;
}
}
}
// Function which has not changed itself, but if any variable in its
// outer context has been added/removed, we must consider this function
// as damaged and not update references to it.
// This is because old compiled function has hardcoded references to
// it's outer context.
bool HasChangedScope(FunctionLiteral* a, FunctionLiteral* b) {
Scope* scope_a = a->scope()->outer_scope();
Scope* scope_b = b->scope()->outer_scope();
while (scope_a && scope_b) {
std::unordered_map<int, Handle<String>> vars;
for (Variable* var : *scope_a->locals()) {
if (!var->IsContextSlot()) continue;
vars[var->index()] = var->name();
}
for (Variable* var : *scope_b->locals()) {
if (!var->IsContextSlot()) continue;
auto it = vars.find(var->index());
if (it == vars.end()) return true;
if (*it->second != *var->name()) return true;
}
scope_a = scope_a->outer_scope();
scope_b = scope_b->outer_scope();
}
return scope_a != scope_b;
}
enum ChangeState { UNCHANGED, CHANGED, DAMAGED };
using LiteralMap = std::unordered_map<FunctionLiteral*, FunctionLiteral*>;
void MapLiterals(const FunctionLiteralChanges& changes,
const std::vector<FunctionLiteral*>& new_literals,
LiteralMap* unchanged, LiteralMap* changed) {
// Track the top-level script function separately as it can overlap fully with
// another function, e.g. the script "()=>42".
const std::pair<int, int> kTopLevelMarker = std::make_pair(-1, -1);
std::map<std::pair<int, int>, FunctionLiteral*> position_to_new_literal;
for (FunctionLiteral* literal : new_literals) {
DCHECK(literal->start_position() != kNoSourcePosition);
DCHECK(literal->end_position() != kNoSourcePosition);
std::pair<int, int> key =
literal->function_literal_id() == kFunctionLiteralIdTopLevel
? kTopLevelMarker
: std::make_pair(literal->start_position(),
literal->end_position());
// Make sure there are no duplicate keys.
DCHECK_EQ(position_to_new_literal.find(key), position_to_new_literal.end());
position_to_new_literal[key] = literal;
}
LiteralMap mappings;
std::unordered_map<FunctionLiteral*, ChangeState> change_state;
for (const auto& change_pair : changes) {
FunctionLiteral* literal = change_pair.first;
const FunctionLiteralChange& change = change_pair.second;
std::pair<int, int> key =
literal->function_literal_id() == kFunctionLiteralIdTopLevel
? kTopLevelMarker
: std::make_pair(change.new_start_position,
change.new_end_position);
auto it = position_to_new_literal.find(key);
if (it == position_to_new_literal.end() ||
HasChangedScope(literal, it->second)) {
change_state[literal] = ChangeState::DAMAGED;
if (!change.outer_literal) continue;
if (change_state[change.outer_literal] != ChangeState::DAMAGED) {
change_state[change.outer_literal] = ChangeState::CHANGED;
}
} else {
mappings[literal] = it->second;
if (change_state.find(literal) == change_state.end()) {
change_state[literal] =
change.has_changes ? ChangeState::CHANGED : ChangeState::UNCHANGED;
}
}
}
for (const auto& mapping : mappings) {
if (change_state[mapping.first] == ChangeState::UNCHANGED) {
(*unchanged)[mapping.first] = mapping.second;
} else if (change_state[mapping.first] == ChangeState::CHANGED) {
(*changed)[mapping.first] = mapping.second;
}
}
}
class CollectFunctionLiterals final
: public AstTraversalVisitor<CollectFunctionLiterals> {
public:
CollectFunctionLiterals(Isolate* isolate, AstNode* root)
: AstTraversalVisitor<CollectFunctionLiterals>(isolate, root) {}
void VisitFunctionLiteral(FunctionLiteral* lit) {
AstTraversalVisitor::VisitFunctionLiteral(lit);
literals_->push_back(lit);
}
void Run(std::vector<FunctionLiteral*>* literals) {
literals_ = literals;
AstTraversalVisitor::Run();
literals_ = nullptr;
}
private:
std::vector<FunctionLiteral*>* literals_;
};
bool ParseScript(Isolate* isolate, Handle<Script> script, ParseInfo* parse_info,
MaybeHandle<ScopeInfo> outer_scope_info, bool compile_as_well,
std::vector<FunctionLiteral*>* literals,
debug::LiveEditResult* result) {
v8::TryCatch try_catch(reinterpret_cast<v8::Isolate*>(isolate));
Handle<SharedFunctionInfo> shared;
bool success = false;
if (compile_as_well) {
success = Compiler::CompileForLiveEdit(parse_info, script, outer_scope_info,
isolate)
.ToHandle(&shared);
} else {
success =
parsing::ParseProgram(parse_info, script, outer_scope_info, isolate,
parsing::ReportStatisticsMode::kYes);
if (!success) {
// Throw the parser error.
parse_info->pending_error_handler()->PrepareErrors(
isolate, parse_info->ast_value_factory());
parse_info->pending_error_handler()->ReportErrors(isolate, script);
}
}
if (!success) {
DCHECK(try_catch.HasCaught());
result->message = try_catch.Message()->Get();
i::Handle<i::JSMessageObject> msg = Utils::OpenHandle(*try_catch.Message());
i::JSMessageObject::EnsureSourcePositionsAvailable(isolate, msg);
result->line_number = msg->GetLineNumber();
result->column_number = msg->GetColumnNumber();
result->status = debug::LiveEditResult::COMPILE_ERROR;
return false;
}
CollectFunctionLiterals(isolate, parse_info->literal()).Run(literals);
return true;
}
struct FunctionData {
explicit FunctionData(FunctionLiteral* literal)
: literal(literal), stack_position(NOT_ON_STACK) {}
FunctionLiteral* literal;
MaybeHandle<SharedFunctionInfo> shared;
std::vector<Handle<JSFunction>> js_functions;
std::vector<Handle<JSGeneratorObject>> running_generators;
// In case of multiple functions with different stack position, the latest
// one (in the order below) is used, since it is the most restrictive.
// This is important only for functions to be restarted.
enum StackPosition { NOT_ON_STACK, ON_TOP_ONLY, ON_STACK };
StackPosition stack_position;
};
class FunctionDataMap : public ThreadVisitor {
public:
void AddInterestingLiteral(int script_id, FunctionLiteral* literal) {
map_.emplace(GetFuncId(script_id, literal), FunctionData{literal});
}
bool Lookup(Tagged<SharedFunctionInfo> sfi, FunctionData** data) {
int start_position = sfi->StartPosition();
if (!IsScript(sfi->script()) || start_position == -1) {
return false;
}
Tagged<Script> script = Script::cast(sfi->script());
return Lookup(GetFuncId(script->id(), sfi), data);
}
bool Lookup(Handle<Script> script, FunctionLiteral* literal,
FunctionData** data) {
return Lookup(GetFuncId(script->id(), literal), data);
}
void Fill(Isolate* isolate) {
{
HeapObjectIterator iterator(isolate->heap(),
HeapObjectIterator::kFilterUnreachable);
for (Tagged<HeapObject> obj = iterator.Next(); !obj.is_null();
obj = iterator.Next()) {
if (IsSharedFunctionInfo(obj)) {
Tagged<SharedFunctionInfo> sfi = SharedFunctionInfo::cast(obj);
FunctionData* data = nullptr;
if (!Lookup(sfi, &data)) continue;
data->shared = handle(sfi, isolate);
} else if (IsJSFunction(obj)) {
Tagged<JSFunction> js_function = JSFunction::cast(obj);
Tagged<SharedFunctionInfo> sfi = js_function->shared();
FunctionData* data = nullptr;
if (!Lookup(sfi, &data)) continue;
data->js_functions.emplace_back(js_function, isolate);
} else if (IsJSGeneratorObject(obj)) {
Tagged<JSGeneratorObject> gen = JSGeneratorObject::cast(obj);
if (gen->is_closed()) continue;
Tagged<SharedFunctionInfo> sfi = gen->function()->shared();
FunctionData* data = nullptr;
if (!Lookup(sfi, &data)) continue;
data->running_generators.emplace_back(gen, isolate);
}
}
}
// Visit the current thread stack.
VisitCurrentThread(isolate);
// Visit the stacks of all archived threads.
isolate->thread_manager()->IterateArchivedThreads(this);
}
private:
// Unique id for a function: script_id + start_position, where start_position
// is special cased to -1 for top-level so that it does not overlap with a
// function whose start position is 0.
using FuncId = std::pair<int, int>;
FuncId GetFuncId(int script_id, FunctionLiteral* literal) {
int start_position = literal->start_position();
if (literal->function_literal_id() == 0) {
// This is the top-level script function literal, so special case its
// start position
DCHECK_EQ(start_position, 0);
start_position = -1;
}
return FuncId(script_id, start_position);
}
FuncId GetFuncId(int script_id, Tagged<SharedFunctionInfo> sfi) {
DCHECK_EQ(script_id, Script::cast(sfi->script())->id());
int start_position = sfi->StartPosition();
DCHECK_NE(start_position, -1);
if (sfi->is_toplevel()) {
// This is the top-level function, so special case its start position
DCHECK_EQ(start_position, 0);
start_position = -1;
}
return FuncId(script_id, start_position);
}
bool Lookup(FuncId id, FunctionData** data) {
auto it = map_.find(id);
if (it == map_.end()) return false;
*data = &it->second;
return true;
}
void VisitThread(Isolate* isolate, ThreadLocalTop* top) override {
for (JavaScriptStackFrameIterator it(isolate, top); !it.done();
it.Advance()) {
std::vector<Handle<SharedFunctionInfo>> sfis;
it.frame()->GetFunctions(&sfis);
for (auto& sfi : sfis) {
FunctionData* data = nullptr;
if (!Lookup(*sfi, &data)) continue;
data->stack_position = FunctionData::ON_STACK;
}
}
}
void VisitCurrentThread(Isolate* isolate) {
// We allow live editing the function that's currently top-of-stack. But
// only if no activation of that function is anywhere else on the stack.
bool is_top = true;
for (DebugStackTraceIterator it(isolate, /* index */ 0); !it.Done();
it.Advance(), is_top = false) {
auto sfi = it.GetSharedFunctionInfo();
if (sfi.is_null()) continue;
FunctionData* data = nullptr;
if (!Lookup(*sfi, &data)) continue;
// ON_TOP_ONLY will only be set on the first iteration (and if the frame
// can be restarted). Further activations will change the ON_TOP_ONLY to
// ON_STACK and prevent the live edit from happening.
data->stack_position = is_top && it.CanBeRestarted()
? FunctionData::ON_TOP_ONLY
: FunctionData::ON_STACK;
}
}
std::map<FuncId, FunctionData> map_;
};
bool CanPatchScript(const LiteralMap& changed, Handle<Script> script,
Handle<Script> new_script,
FunctionDataMap& function_data_map,
bool allow_top_frame_live_editing,
debug::LiveEditResult* result) {
for (const auto& mapping : changed) {
FunctionData* data = nullptr;
function_data_map.Lookup(script, mapping.first, &data);
FunctionData* new_data = nullptr;
function_data_map.Lookup(new_script, mapping.second, &new_data);
Handle<SharedFunctionInfo> sfi;
if (!data->shared.ToHandle(&sfi)) {
continue;
} else if (IsModule(sfi->kind())) {
DCHECK(script->origin_options().IsModule() && sfi->is_toplevel());
result->status =
debug::LiveEditResult::BLOCKED_BY_TOP_LEVEL_ES_MODULE_CHANGE;
return false;
} else if (data->stack_position == FunctionData::ON_STACK) {
result->status = debug::LiveEditResult::BLOCKED_BY_ACTIVE_FUNCTION;
return false;
} else if (!data->running_generators.empty()) {
result->status = debug::LiveEditResult::BLOCKED_BY_RUNNING_GENERATOR;
return false;
} else if (data->stack_position == FunctionData::ON_TOP_ONLY) {
if (!allow_top_frame_live_editing) {
result->status = debug::LiveEditResult::BLOCKED_BY_ACTIVE_FUNCTION;
return false;
}
result->restart_top_frame_required = true;
}
}
return true;
}
void TranslateSourcePositionTable(Isolate* isolate, Handle<BytecodeArray> code,
const std::vector<SourceChangeRange>& diffs) {
Zone zone(isolate->allocator(), ZONE_NAME);
SourcePositionTableBuilder builder(&zone);
Handle<TrustedByteArray> source_position_table(code->SourcePositionTable(),
isolate);
for (SourcePositionTableIterator iterator(*source_position_table);
!iterator.done(); iterator.Advance()) {
SourcePosition position = iterator.source_position();
position.SetScriptOffset(
LiveEdit::TranslatePosition(diffs, position.ScriptOffset()));
builder.AddPosition(iterator.code_offset(), position,
iterator.is_statement());
}
Handle<TrustedByteArray> new_source_position_table(
builder.ToSourcePositionTable(isolate));
code->set_source_position_table(*new_source_position_table, kReleaseStore);
LOG_CODE_EVENT(isolate,
CodeLinePosInfoRecordEvent(code->GetFirstBytecodeAddress(),
*new_source_position_table,
JitCodeEvent::BYTE_CODE));
}
void UpdatePositions(Isolate* isolate, Handle<SharedFunctionInfo> sfi,
FunctionLiteral* new_function,
const std::vector<SourceChangeRange>& diffs) {
sfi->UpdateFromFunctionLiteralForLiveEdit(new_function);
if (sfi->HasBytecodeArray()) {
TranslateSourcePositionTable(
isolate, handle(sfi->GetBytecodeArray(isolate), isolate), diffs);
}
}
#ifdef DEBUG
Tagged<ScopeInfo> FindOuterScopeInfoFromScriptSfi(Isolate* isolate,
Handle<Script> script) {
// We take some SFI from the script and walk outwards until we find the
// EVAL_SCOPE. Then we do the same search as `DetermineOuterScopeInfo` and
// check that we found the same ScopeInfo.
SharedFunctionInfo::ScriptIterator it(isolate, *script);
Tagged<ScopeInfo> other_scope_info;
for (Tagged<SharedFunctionInfo> sfi = it.Next(); !sfi.is_null();
sfi = it.Next()) {
if (!sfi->scope_info()->IsEmpty()) {
other_scope_info = sfi->scope_info();
break;
}
}
if (other_scope_info.is_null()) return other_scope_info;
while (!other_scope_info->IsEmpty() &&
other_scope_info->scope_type() != EVAL_SCOPE &&
other_scope_info->HasOuterScopeInfo()) {
other_scope_info = other_scope_info->OuterScopeInfo();
}
// This function is only called when we found a ScopeInfo candidate, so
// technically the EVAL_SCOPE must have an outer_scope_info. But, the GC can
// clean up some ScopeInfos it thinks are no longer needed. Abort the check
// in that case.
if (!other_scope_info->HasOuterScopeInfo()) return ScopeInfo();
DCHECK_EQ(other_scope_info->scope_type(), EVAL_SCOPE);
other_scope_info = other_scope_info->OuterScopeInfo();
while (!other_scope_info->IsEmpty() && !other_scope_info->HasContext() &&
other_scope_info->HasOuterScopeInfo()) {
other_scope_info = other_scope_info->OuterScopeInfo();
}
return other_scope_info;
}
#endif
// For sloppy eval we need to know the ScopeInfo the eval was compiled in and
// re-use it when we compile the new version of the script.
MaybeHandle<ScopeInfo> DetermineOuterScopeInfo(Isolate* isolate,
Handle<Script> script) {
if (!script->has_eval_from_shared()) return kNullMaybeHandle;
DCHECK_EQ(script->compilation_type(), Script::CompilationType::kEval);
Tagged<ScopeInfo> scope_info = script->eval_from_shared()->scope_info();
// Sloppy eval compiles use the ScopeInfo of the context. Let's find it.
while (!scope_info->IsEmpty()) {
if (scope_info->HasContext()) {
#ifdef DEBUG
Tagged<ScopeInfo> other_scope_info =
FindOuterScopeInfoFromScriptSfi(isolate, script);
DCHECK_IMPLIES(!other_scope_info.is_null(),
scope_info == other_scope_info);
#endif
return handle(scope_info, isolate);
} else if (!scope_info->HasOuterScopeInfo()) {
break;
}
scope_info = scope_info->OuterScopeInfo();
}
return kNullMaybeHandle;
}
} // anonymous namespace
void LiveEdit::PatchScript(Isolate* isolate, Handle<Script> script,
Handle<String> new_source, bool preview,
bool allow_top_frame_live_editing,
debug::LiveEditResult* result) {
std::vector<SourceChangeRange> diffs;
LiveEdit::CompareStrings(isolate,
handle(String::cast(script->source()), isolate),
new_source, &diffs);
if (diffs.empty()) {
result->status = debug::LiveEditResult::OK;
return;
}
ReusableUnoptimizedCompileState reusable_state(isolate);
UnoptimizedCompileState compile_state;
UnoptimizedCompileFlags flags =
UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
flags.set_is_eager(true);
flags.set_is_reparse(true);
ParseInfo parse_info(isolate, flags, &compile_state, &reusable_state);
MaybeHandle<ScopeInfo> outer_scope_info =
DetermineOuterScopeInfo(isolate, script);
std::vector<FunctionLiteral*> literals;
if (!ParseScript(isolate, script, &parse_info, outer_scope_info, false,
&literals, result))
return;
Handle<Script> new_script =
isolate->factory()->CloneScript(script, new_source);
UnoptimizedCompileState new_compile_state;
UnoptimizedCompileFlags new_flags =
UnoptimizedCompileFlags::ForScriptCompile(isolate, *new_script);
new_flags.set_is_eager(true);
ParseInfo new_parse_info(isolate, new_flags, &new_compile_state,
&reusable_state);
std::vector<FunctionLiteral*> new_literals;
if (!ParseScript(isolate, new_script, &new_parse_info, outer_scope_info, true,
&new_literals, result)) {
return;
}
FunctionLiteralChanges literal_changes;
CalculateFunctionLiteralChanges(literals, diffs, &literal_changes);
LiteralMap changed;
LiteralMap unchanged;
MapLiterals(literal_changes, new_literals, &unchanged, &changed);
FunctionDataMap function_data_map;
for (const auto& mapping : changed) {
function_data_map.AddInterestingLiteral(script->id(), mapping.first);
function_data_map.AddInterestingLiteral(new_script->id(), mapping.second);
}
for (const auto& mapping : unchanged) {
function_data_map.AddInterestingLiteral(script->id(), mapping.first);
}
function_data_map.Fill(isolate);
if (!CanPatchScript(changed, script, new_script, function_data_map,
allow_top_frame_live_editing, result)) {
return;
}
if (preview) {
result->status = debug::LiveEditResult::OK;
return;
}
// Patching a script means that the bytecode on the stack may no longer
// correspond to the bytecode of the JSFunction for that frame. As a result
// it is no longer safe to flush bytecode since we might flush the new
// bytecode for a JSFunction that is on the stack with an old bytecode, which
// breaks the invariant that any JSFunction active on the stack is compiled.
isolate->set_disable_bytecode_flushing(true);
std::map<int, int> start_position_to_unchanged_id;
for (const auto& mapping : unchanged) {
FunctionData* data = nullptr;
if (!function_data_map.Lookup(script, mapping.first, &data)) continue;
Handle<SharedFunctionInfo> sfi;
if (!data->shared.ToHandle(&sfi)) continue;
DCHECK_EQ(sfi->script(), *script);
isolate->compilation_cache()->Remove(sfi);
isolate->debug()->DeoptimizeFunction(sfi);
if (base::Optional<Tagged<DebugInfo>> di = sfi->TryGetDebugInfo(isolate)) {
Handle<DebugInfo> debug_info(di.value(), isolate);
isolate->debug()->RemoveBreakInfoAndMaybeFree(debug_info);
}
SharedFunctionInfo::EnsureSourcePositionsAvailable(isolate, sfi);
UpdatePositions(isolate, sfi, mapping.second, diffs);
sfi->set_script(*new_script, kReleaseStore);
sfi->set_function_literal_id(mapping.second->function_literal_id());
new_script->shared_function_infos()->set(
mapping.second->function_literal_id(), MakeWeak(*sfi));
DCHECK_EQ(sfi->function_literal_id(),
mapping.second->function_literal_id());
// Save the new start_position -> id mapping, so that we can recover it when
// iterating over changed functions' constant pools.
start_position_to_unchanged_id[mapping.second->start_position()] =
mapping.second->function_literal_id();
if (sfi->HasUncompiledDataWithPreparseData()) {
sfi->ClearPreparseData();
}
for (auto& js_function : data->js_functions) {
js_function->set_raw_feedback_cell(
*isolate->factory()->many_closures_cell());
if (!js_function->is_compiled(isolate)) continue;
IsCompiledScope is_compiled_scope(
js_function->shared()->is_compiled_scope(isolate));
JSFunction::EnsureFeedbackVector(isolate, js_function,
&is_compiled_scope);
}
if (!sfi->HasBytecodeArray()) continue;
Tagged<TrustedFixedArray> constants =
sfi->GetBytecodeArray(isolate)->constant_pool();
for (int i = 0; i < constants->length(); ++i) {
if (!IsSharedFunctionInfo(constants->get(i))) continue;
data = nullptr;
if (!function_data_map.Lookup(SharedFunctionInfo::cast(constants->get(i)),
&data)) {
continue;
}
auto change_it = changed.find(data->literal);
if (change_it == changed.end()) continue;
if (!function_data_map.Lookup(new_script, change_it->second, &data)) {
continue;
}
Handle<SharedFunctionInfo> new_sfi;
if (!data->shared.ToHandle(&new_sfi)) continue;
constants->set(i, *new_sfi);
}
}
for (const auto& mapping : changed) {
FunctionData* data = nullptr;
if (!function_data_map.Lookup(new_script, mapping.second, &data)) continue;
Handle<SharedFunctionInfo> new_sfi;
// In most cases the new FunctionLiteral should also have an SFI, but there
// are some exceptions. E.g the compiler doesn't create SFIs for
// inner functions that are never referenced.
if (!data->shared.ToHandle(&new_sfi)) continue;
DCHECK_EQ(new_sfi->script(), *new_script);
if (!function_data_map.Lookup(script, mapping.first, &data)) continue;
Handle<SharedFunctionInfo> sfi;
if (!data->shared.ToHandle(&sfi)) continue;
isolate->debug()->DeoptimizeFunction(sfi);
isolate->compilation_cache()->Remove(sfi);
for (auto& js_function : data->js_functions) {
js_function->set_shared(*new_sfi);
js_function->set_code(js_function->shared()->GetCode(isolate));
js_function->set_raw_feedback_cell(
*isolate->factory()->many_closures_cell());
if (!js_function->is_compiled(isolate)) continue;
IsCompiledScope is_compiled_scope(
js_function->shared()->is_compiled_scope(isolate));
JSFunction::EnsureFeedbackVector(isolate, js_function,
&is_compiled_scope);
}
}
SharedFunctionInfo::ScriptIterator it(isolate, *new_script);
for (Tagged<SharedFunctionInfo> sfi = it.Next(); !sfi.is_null();
sfi = it.Next()) {
if (!sfi->HasBytecodeArray()) continue;
Tagged<TrustedFixedArray> constants =
sfi->GetBytecodeArray(isolate)->constant_pool();
for (int i = 0; i < constants->length(); ++i) {
if (!IsSharedFunctionInfo(constants->get(i))) continue;
Tagged<SharedFunctionInfo> inner_sfi =
SharedFunctionInfo::cast(constants->get(i));
// See if there is a mapping from this function's start position to a
// unchanged function's id.
auto unchanged_it =
start_position_to_unchanged_id.find(inner_sfi->StartPosition());
if (unchanged_it == start_position_to_unchanged_id.end()) continue;
// Grab that function id from the new script's SFI list, which should have
// already been updated in in the unchanged pass.
Tagged<SharedFunctionInfo> old_unchanged_inner_sfi =
SharedFunctionInfo::cast(new_script->shared_function_infos()
->get(unchanged_it->second)
.GetHeapObject());
if (old_unchanged_inner_sfi == inner_sfi) continue;
DCHECK_NE(old_unchanged_inner_sfi, inner_sfi);
// Now some sanity checks. Make sure that the unchanged SFI has already
// been processed and patched to be on the new script ...
DCHECK_EQ(old_unchanged_inner_sfi->script(), *new_script);
constants->set(i, old_unchanged_inner_sfi);
}
}
#ifdef DEBUG
{
// Check that all the functions in the new script are valid, that their
// function literals match what is expected, and that start positions are
// unique.
DisallowGarbageCollection no_gc;
SharedFunctionInfo::ScriptIterator script_it(isolate, *new_script);
std::set<int> start_positions;
for (Tagged<SharedFunctionInfo> sfi = script_it.Next(); !sfi.is_null();
sfi = script_it.Next()) {
DCHECK_EQ(sfi->script(), *new_script);
DCHECK_EQ(sfi->function_literal_id(), script_it.CurrentIndex());
// Don't check the start position of the top-level function, as it can
// overlap with a function in the script.
if (sfi->is_toplevel()) {
DCHECK_EQ(start_positions.find(sfi->StartPosition()),
start_positions.end());
start_positions.insert(sfi->StartPosition());
}
if (!sfi->HasBytecodeArray()) continue;
// Check that all the functions in this function's constant pool are also
// on the new script, and that their id matches their index in the new
// scripts function list.
Tagged<TrustedFixedArray> constants =
sfi->GetBytecodeArray(isolate)->constant_pool();
for (int i = 0; i < constants->length(); ++i) {
if (!IsSharedFunctionInfo(constants->get(i))) continue;
Tagged<SharedFunctionInfo> inner_sfi =
SharedFunctionInfo::cast(constants->get(i));
DCHECK_EQ(inner_sfi->script(), *new_script);
DCHECK_EQ(inner_sfi, new_script->shared_function_infos()
->get(inner_sfi->function_literal_id())
.GetHeapObject());
}
}
}
#endif
int script_id = script->id();
script->set_id(new_script->id());
new_script->set_id(script_id);
result->status = debug::LiveEditResult::OK;
result->script = ToApiHandle<v8::debug::Script>(new_script);
}
void LiveEdit::CompareStrings(Isolate* isolate, Handle<String> s1,
Handle<String> s2,
std::vector<SourceChangeRange>* diffs) {
s1 = String::Flatten(isolate, s1);
s2 = String::Flatten(isolate, s2);
LineEndsWrapper line_ends1(isolate, s1);
LineEndsWrapper line_ends2(isolate, s2);
LineArrayCompareInput input(s1, s2, line_ends1, line_ends2);
TokenizingLineArrayCompareOutput output(isolate, line_ends1, line_ends2, s1,
s2, diffs);
NarrowDownInput(&input, &output);
Comparator::CalculateDifference(&input, &output);
}
int LiveEdit::TranslatePosition(const std::vector<SourceChangeRange>& diffs,
int position) {
auto it = std::lower_bound(diffs.begin(), diffs.end(), position,
[](const SourceChangeRange& change, int position) {
return change.end_position < position;
});
if (it != diffs.end() && position == it->end_position) {
return it->new_end_position;
}
if (it == diffs.begin()) return position;
DCHECK(it == diffs.end() || position <= it->start_position);
it = std::prev(it);
return position + (it->new_end_position - it->end_position);
}
} // namespace internal
} // namespace v8