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v8/src/liveedit.cc
mstarzinger@chromium.org f8db2414f2 Deprecate FACTORY helper macro. 
This removes the FACTORY helper macro to avoid accidental TLS access
when using the factory. Most internal code has access to the Isolate by
now whereas tests which are not performance critical still heavily use
TLS access through explicit Isolate::Current() calls.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/16337005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14931 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-06-04 10:30:05 +00:00

2132 lines
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// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "liveedit.h"
#include "code-stubs.h"
#include "compilation-cache.h"
#include "compiler.h"
#include "debug.h"
#include "deoptimizer.h"
#include "global-handles.h"
#include "messages.h"
#include "parser.h"
#include "scopeinfo.h"
#include "scopes.h"
#include "v8memory.h"
namespace v8 {
namespace internal {
#ifdef ENABLE_DEBUGGER_SUPPORT
void SetElementNonStrict(Handle<JSObject> object,
uint32_t index,
Handle<Object> value) {
// Ignore return value from SetElement. It can only be a failure if there
// are element setters causing exceptions and the debugger context has none
// of these.
Handle<Object> no_failure =
JSObject::SetElement(object, index, value, NONE, kNonStrictMode);
ASSERT(!no_failure.is_null());
USE(no_failure);
}
// A simple implementation of dynamic programming algorithm. It solves
// the problem of finding the difference of 2 arrays. It uses a table of results
// of subproblems. Each cell contains a number together with 2-bit flag
// that helps building the chunk list.
class Differencer {
public:
explicit Differencer(Comparator::Input* input)
: input_(input), len1_(input->GetLength1()), len2_(input->GetLength2()) {
buffer_ = NewArray<int>(len1_ * len2_);
}
~Differencer() {
DeleteArray(buffer_);
}
void Initialize() {
int array_size = len1_ * len2_;
for (int i = 0; i < array_size; i++) {
buffer_[i] = kEmptyCellValue;
}
}
// Makes sure that result for the full problem is calculated and stored
// in the table together with flags showing a path through subproblems.
void FillTable() {
CompareUpToTail(0, 0);
}
void SaveResult(Comparator::Output* chunk_writer) {
ResultWriter writer(chunk_writer);
int pos1 = 0;
int pos2 = 0;
while (true) {
if (pos1 < len1_) {
if (pos2 < len2_) {
Direction dir = get_direction(pos1, pos2);
switch (dir) {
case EQ:
writer.eq();
pos1++;
pos2++;
break;
case SKIP1:
writer.skip1(1);
pos1++;
break;
case SKIP2:
case SKIP_ANY:
writer.skip2(1);
pos2++;
break;
default:
UNREACHABLE();
}
} else {
writer.skip1(len1_ - pos1);
break;
}
} else {
if (len2_ != pos2) {
writer.skip2(len2_ - pos2);
}
break;
}
}
writer.close();
}
private:
Comparator::Input* input_;
int* buffer_;
int len1_;
int len2_;
enum Direction {
EQ = 0,
SKIP1,
SKIP2,
SKIP_ANY,
MAX_DIRECTION_FLAG_VALUE = SKIP_ANY
};
// Computes result for a subtask and optionally caches it in the buffer table.
// All results values are shifted to make space for flags in the lower bits.
int CompareUpToTail(int pos1, int pos2) {
if (pos1 < len1_) {
if (pos2 < len2_) {
int cached_res = get_value4(pos1, pos2);
if (cached_res == kEmptyCellValue) {
Direction dir;
int res;
if (input_->Equals(pos1, pos2)) {
res = CompareUpToTail(pos1 + 1, pos2 + 1);
dir = EQ;
} else {
int res1 = CompareUpToTail(pos1 + 1, pos2) +
(1 << kDirectionSizeBits);
int res2 = CompareUpToTail(pos1, pos2 + 1) +
(1 << kDirectionSizeBits);
if (res1 == res2) {
res = res1;
dir = SKIP_ANY;
} else if (res1 < res2) {
res = res1;
dir = SKIP1;
} else {
res = res2;
dir = SKIP2;
}
}
set_value4_and_dir(pos1, pos2, res, dir);
cached_res = res;
}
return cached_res;
} else {
return (len1_ - pos1) << kDirectionSizeBits;
}
} else {
return (len2_ - pos2) << kDirectionSizeBits;
}
}
inline int& get_cell(int i1, int i2) {
return buffer_[i1 + i2 * len1_];
}
// Each cell keeps a value plus direction. Value is multiplied by 4.
void set_value4_and_dir(int i1, int i2, int value4, Direction dir) {
ASSERT((value4 & kDirectionMask) == 0);
get_cell(i1, i2) = value4 | dir;
}
int get_value4(int i1, int i2) {
return get_cell(i1, i2) & (kMaxUInt32 ^ kDirectionMask);
}
Direction get_direction(int i1, int i2) {
return static_cast<Direction>(get_cell(i1, i2) & kDirectionMask);
}
static const int kDirectionSizeBits = 2;
static const int kDirectionMask = (1 << kDirectionSizeBits) - 1;
static const int kEmptyCellValue = -1 << kDirectionSizeBits;
// This method only holds static assert statement (unfortunately you cannot
// place one in class scope).
void StaticAssertHolder() {
STATIC_ASSERT(MAX_DIRECTION_FLAG_VALUE < (1 << kDirectionSizeBits));
}
class ResultWriter {
public:
explicit ResultWriter(Comparator::Output* chunk_writer)
: chunk_writer_(chunk_writer), pos1_(0), pos2_(0),
pos1_begin_(-1), pos2_begin_(-1), has_open_chunk_(false) {
}
void eq() {
FlushChunk();
pos1_++;
pos2_++;
}
void skip1(int len1) {
StartChunk();
pos1_ += len1;
}
void skip2(int len2) {
StartChunk();
pos2_ += len2;
}
void close() {
FlushChunk();
}
private:
Comparator::Output* chunk_writer_;
int pos1_;
int pos2_;
int pos1_begin_;
int pos2_begin_;
bool has_open_chunk_;
void StartChunk() {
if (!has_open_chunk_) {
pos1_begin_ = pos1_;
pos2_begin_ = pos2_;
has_open_chunk_ = true;
}
}
void FlushChunk() {
if (has_open_chunk_) {
chunk_writer_->AddChunk(pos1_begin_, pos2_begin_,
pos1_ - pos1_begin_, pos2_ - pos2_begin_);
has_open_chunk_ = false;
}
}
};
};
void Comparator::CalculateDifference(Comparator::Input* input,
Comparator::Output* result_writer) {
Differencer differencer(input);
differencer.Initialize();
differencer.FillTable();
differencer.SaveResult(result_writer);
}
static 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;
};
static int min(int a, int b) {
return a < b ? a : b;
}
// Finds common prefix and suffix in input. This parts shouldn't take space in
// linear programming table. Enable subranging in input and output.
static 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 = 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 = 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);
}
}
// A helper class that writes chunk numbers into JSArray.
// Each chunk is stored as 3 array elements: (pos1_begin, pos1_end, pos2_end).
class CompareOutputArrayWriter {
public:
explicit CompareOutputArrayWriter(Isolate* isolate)
: array_(isolate->factory()->NewJSArray(10)), current_size_(0) {}
Handle<JSArray> GetResult() {
return array_;
}
void WriteChunk(int char_pos1, int char_pos2, int char_len1, int char_len2) {
Isolate* isolate = array_->GetIsolate();
SetElementNonStrict(array_,
current_size_,
Handle<Object>(Smi::FromInt(char_pos1), isolate));
SetElementNonStrict(array_,
current_size_ + 1,
Handle<Object>(Smi::FromInt(char_pos1 + char_len1),
isolate));
SetElementNonStrict(array_,
current_size_ + 2,
Handle<Object>(Smi::FromInt(char_pos2 + char_len2),
isolate));
current_size_ += 3;
}
private:
Handle<JSArray> array_;
int current_size_;
};
// 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) {
}
virtual int GetLength1() {
return len1_;
}
virtual int GetLength2() {
return len2_;
}
bool Equals(int index1, int index2) {
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 JSArray. Converts substring positions
// to absolute positions.
class TokensCompareOutput : public Comparator::Output {
public:
TokensCompareOutput(CompareOutputArrayWriter* array_writer,
int offset1, int offset2)
: array_writer_(array_writer), offset1_(offset1), offset2_(offset2) {
}
void AddChunk(int pos1, int pos2, int len1, int len2) {
array_writer_->WriteChunk(pos1 + offset1_, pos2 + offset2_, len1, len2);
}
private:
CompareOutputArrayWriter* array_writer_;
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(Handle<String> string)
: ends_array_(CalculateLineEnds(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) {
if (index == 0) {
return 0;
} else {
return 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::cast(ends_array_->get(index))->value() + 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() {
return subrange_len1_;
}
int GetLength2() {
return subrange_len2_;
}
bool Equals(int index1, int index2) {
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) {
subrange_offset1_ = offset;
subrange_len1_ = len;
}
void SetSubrange2(int offset, int len) {
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 JSArray. For each chunk tries to conduct
// a fine-grained nested diff token-wise.
class TokenizingLineArrayCompareOutput : public SubrangableOutput {
public:
TokenizingLineArrayCompareOutput(LineEndsWrapper line_ends1,
LineEndsWrapper line_ends2,
Handle<String> s1, Handle<String> s2)
: array_writer_(s1->GetIsolate()),
line_ends1_(line_ends1), line_ends2_(line_ends2), s1_(s1), s2_(s2),
subrange_offset1_(0), subrange_offset2_(0) {
}
void AddChunk(int line_pos1, int line_pos2, int line_len1, int line_len2) {
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(s1_->GetIsolate());
TokensCompareInput tokens_input(s1_, char_pos1, char_len1,
s2_, char_pos2, char_len2);
TokensCompareOutput tokens_output(&array_writer_, char_pos1,
char_pos2);
Comparator::CalculateDifference(&tokens_input, &tokens_output);
} else {
array_writer_.WriteChunk(char_pos1, char_pos2, char_len1, char_len2);
}
}
void SetSubrange1(int offset, int len) {
subrange_offset1_ = offset;
}
void SetSubrange2(int offset, int len) {
subrange_offset2_ = offset;
}
Handle<JSArray> GetResult() {
return array_writer_.GetResult();
}
private:
static const int CHUNK_LEN_LIMIT = 800;
CompareOutputArrayWriter array_writer_;
LineEndsWrapper line_ends1_;
LineEndsWrapper line_ends2_;
Handle<String> s1_;
Handle<String> s2_;
int subrange_offset1_;
int subrange_offset2_;
};
Handle<JSArray> LiveEdit::CompareStrings(Handle<String> s1,
Handle<String> s2) {
s1 = FlattenGetString(s1);
s2 = FlattenGetString(s2);
LineEndsWrapper line_ends1(s1);
LineEndsWrapper line_ends2(s2);
LineArrayCompareInput input(s1, s2, line_ends1, line_ends2);
TokenizingLineArrayCompareOutput output(line_ends1, line_ends2, s1, s2);
NarrowDownInput(&input, &output);
Comparator::CalculateDifference(&input, &output);
return output.GetResult();
}
static void CompileScriptForTracker(Isolate* isolate, Handle<Script> script) {
// TODO(635): support extensions.
PostponeInterruptsScope postpone(isolate);
// Build AST.
CompilationInfoWithZone info(script);
info.MarkAsGlobal();
// Parse and don't allow skipping lazy functions.
if (Parser::Parse(&info)) {
// Compile the code.
LiveEditFunctionTracker tracker(info.isolate(), info.function());
if (Compiler::MakeCodeForLiveEdit(&info)) {
ASSERT(!info.code().is_null());
tracker.RecordRootFunctionInfo(info.code());
} else {
info.isolate()->StackOverflow();
}
}
}
// Unwraps JSValue object, returning its field "value"
static Handle<Object> UnwrapJSValue(Handle<JSValue> jsValue) {
return Handle<Object>(jsValue->value(), jsValue->GetIsolate());
}
// Wraps any object into a OpaqueReference, that will hide the object
// from JavaScript.
static Handle<JSValue> WrapInJSValue(Handle<Object> object) {
Isolate* isolate = Isolate::Current();
Handle<JSFunction> constructor = isolate->opaque_reference_function();
Handle<JSValue> result =
Handle<JSValue>::cast(isolate->factory()->NewJSObject(constructor));
result->set_value(*object);
return result;
}
static Handle<SharedFunctionInfo> UnwrapSharedFunctionInfoFromJSValue(
Handle<JSValue> jsValue) {
Object* shared = jsValue->value();
CHECK(shared->IsSharedFunctionInfo());
return Handle<SharedFunctionInfo>(SharedFunctionInfo::cast(shared));
}
static int GetArrayLength(Handle<JSArray> array) {
Object* length = array->length();
CHECK(length->IsSmi());
return Smi::cast(length)->value();
}
// Simple helper class that creates more or less typed structures over
// JSArray object. This is an adhoc method of passing structures from C++
// to JavaScript.
template<typename S>
class JSArrayBasedStruct {
public:
static S Create() {
Factory* factory = Isolate::Current()->factory();
Handle<JSArray> array = factory->NewJSArray(S::kSize_);
return S(array);
}
static S cast(Object* object) {
JSArray* array = JSArray::cast(object);
Handle<JSArray> array_handle(array);
return S(array_handle);
}
explicit JSArrayBasedStruct(Handle<JSArray> array) : array_(array) {
}
Handle<JSArray> GetJSArray() {
return array_;
}
Isolate* isolate() const {
return array_->GetIsolate();
}
protected:
void SetField(int field_position, Handle<Object> value) {
SetElementNonStrict(array_, field_position, value);
}
void SetSmiValueField(int field_position, int value) {
SetElementNonStrict(array_,
field_position,
Handle<Smi>(Smi::FromInt(value), isolate()));
}
Object* GetField(int field_position) {
return array_->GetElementNoExceptionThrown(field_position);
}
int GetSmiValueField(int field_position) {
Object* res = GetField(field_position);
CHECK(res->IsSmi());
return Smi::cast(res)->value();
}
private:
Handle<JSArray> array_;
};
// Represents some function compilation details. This structure will be used
// from JavaScript. It contains Code object, which is kept wrapped
// into a BlindReference for sanitizing reasons.
class FunctionInfoWrapper : public JSArrayBasedStruct<FunctionInfoWrapper> {
public:
explicit FunctionInfoWrapper(Handle<JSArray> array)
: JSArrayBasedStruct<FunctionInfoWrapper>(array) {
}
void SetInitialProperties(Handle<String> name, int start_position,
int end_position, int param_num,
int literal_count, int parent_index) {
HandleScope scope(isolate());
this->SetField(kFunctionNameOffset_, name);
this->SetSmiValueField(kStartPositionOffset_, start_position);
this->SetSmiValueField(kEndPositionOffset_, end_position);
this->SetSmiValueField(kParamNumOffset_, param_num);
this->SetSmiValueField(kLiteralNumOffset_, literal_count);
this->SetSmiValueField(kParentIndexOffset_, parent_index);
}
void SetFunctionCode(Handle<Code> function_code,
Handle<Object> code_scope_info) {
Handle<JSValue> code_wrapper = WrapInJSValue(function_code);
this->SetField(kCodeOffset_, code_wrapper);
Handle<JSValue> scope_wrapper = WrapInJSValue(code_scope_info);
this->SetField(kCodeScopeInfoOffset_, scope_wrapper);
}
void SetOuterScopeInfo(Handle<Object> scope_info_array) {
this->SetField(kOuterScopeInfoOffset_, scope_info_array);
}
void SetSharedFunctionInfo(Handle<SharedFunctionInfo> info) {
Handle<JSValue> info_holder = WrapInJSValue(info);
this->SetField(kSharedFunctionInfoOffset_, info_holder);
}
int GetLiteralCount() {
return this->GetSmiValueField(kLiteralNumOffset_);
}
int GetParentIndex() {
return this->GetSmiValueField(kParentIndexOffset_);
}
Handle<Code> GetFunctionCode() {
Object* element = this->GetField(kCodeOffset_);
CHECK(element->IsJSValue());
Handle<JSValue> value_wrapper(JSValue::cast(element));
Handle<Object> raw_result = UnwrapJSValue(value_wrapper);
CHECK(raw_result->IsCode());
return Handle<Code>::cast(raw_result);
}
Handle<Object> GetCodeScopeInfo() {
Object* element = this->GetField(kCodeScopeInfoOffset_);
CHECK(element->IsJSValue());
return UnwrapJSValue(Handle<JSValue>(JSValue::cast(element)));
}
int GetStartPosition() {
return this->GetSmiValueField(kStartPositionOffset_);
}
int GetEndPosition() {
return this->GetSmiValueField(kEndPositionOffset_);
}
private:
static const int kFunctionNameOffset_ = 0;
static const int kStartPositionOffset_ = 1;
static const int kEndPositionOffset_ = 2;
static const int kParamNumOffset_ = 3;
static const int kCodeOffset_ = 4;
static const int kCodeScopeInfoOffset_ = 5;
static const int kOuterScopeInfoOffset_ = 6;
static const int kParentIndexOffset_ = 7;
static const int kSharedFunctionInfoOffset_ = 8;
static const int kLiteralNumOffset_ = 9;
static const int kSize_ = 10;
friend class JSArrayBasedStruct<FunctionInfoWrapper>;
};
// Wraps SharedFunctionInfo along with some of its fields for passing it
// back to JavaScript. SharedFunctionInfo object itself is additionally
// wrapped into BlindReference for sanitizing reasons.
class SharedInfoWrapper : public JSArrayBasedStruct<SharedInfoWrapper> {
public:
static bool IsInstance(Handle<JSArray> array) {
return array->length() == Smi::FromInt(kSize_) &&
array->GetElementNoExceptionThrown(kSharedInfoOffset_)->IsJSValue();
}
explicit SharedInfoWrapper(Handle<JSArray> array)
: JSArrayBasedStruct<SharedInfoWrapper>(array) {
}
void SetProperties(Handle<String> name, int start_position, int end_position,
Handle<SharedFunctionInfo> info) {
HandleScope scope(isolate());
this->SetField(kFunctionNameOffset_, name);
Handle<JSValue> info_holder = WrapInJSValue(info);
this->SetField(kSharedInfoOffset_, info_holder);
this->SetSmiValueField(kStartPositionOffset_, start_position);
this->SetSmiValueField(kEndPositionOffset_, end_position);
}
Handle<SharedFunctionInfo> GetInfo() {
Object* element = this->GetField(kSharedInfoOffset_);
CHECK(element->IsJSValue());
Handle<JSValue> value_wrapper(JSValue::cast(element));
return UnwrapSharedFunctionInfoFromJSValue(value_wrapper);
}
private:
static const int kFunctionNameOffset_ = 0;
static const int kStartPositionOffset_ = 1;
static const int kEndPositionOffset_ = 2;
static const int kSharedInfoOffset_ = 3;
static const int kSize_ = 4;
friend class JSArrayBasedStruct<SharedInfoWrapper>;
};
class FunctionInfoListener {
public:
explicit FunctionInfoListener(Isolate* isolate) {
current_parent_index_ = -1;
len_ = 0;
result_ = isolate->factory()->NewJSArray(10);
}
void FunctionStarted(FunctionLiteral* fun) {
HandleScope scope(isolate());
FunctionInfoWrapper info = FunctionInfoWrapper::Create();
info.SetInitialProperties(fun->name(), fun->start_position(),
fun->end_position(), fun->parameter_count(),
fun->materialized_literal_count(),
current_parent_index_);
current_parent_index_ = len_;
SetElementNonStrict(result_, len_, info.GetJSArray());
len_++;
}
void FunctionDone() {
HandleScope scope(isolate());
FunctionInfoWrapper info =
FunctionInfoWrapper::cast(
result_->GetElementNoExceptionThrown(current_parent_index_));
current_parent_index_ = info.GetParentIndex();
}
// Saves only function code, because for a script function we
// may never create a SharedFunctionInfo object.
void FunctionCode(Handle<Code> function_code) {
FunctionInfoWrapper info =
FunctionInfoWrapper::cast(
result_->GetElementNoExceptionThrown(current_parent_index_));
info.SetFunctionCode(function_code,
Handle<Object>(isolate()->heap()->null_value(),
isolate()));
}
// Saves full information about a function: its code, its scope info
// and a SharedFunctionInfo object.
void FunctionInfo(Handle<SharedFunctionInfo> shared, Scope* scope,
Zone* zone) {
if (!shared->IsSharedFunctionInfo()) {
return;
}
FunctionInfoWrapper info =
FunctionInfoWrapper::cast(
result_->GetElementNoExceptionThrown(current_parent_index_));
info.SetFunctionCode(Handle<Code>(shared->code()),
Handle<Object>(shared->scope_info(), isolate()));
info.SetSharedFunctionInfo(shared);
Handle<Object> scope_info_list(SerializeFunctionScope(scope, zone),
isolate());
info.SetOuterScopeInfo(scope_info_list);
}
Handle<JSArray> GetResult() { return result_; }
private:
Isolate* isolate() const { return result_->GetIsolate(); }
Object* SerializeFunctionScope(Scope* scope, Zone* zone) {
HandleScope handle_scope(isolate());
Handle<JSArray> scope_info_list = isolate()->factory()->NewJSArray(10);
int scope_info_length = 0;
// Saves some description of scope. It stores name and indexes of
// variables in the whole scope chain. Null-named slots delimit
// scopes of this chain.
Scope* outer_scope = scope->outer_scope();
if (outer_scope == NULL) {
return isolate()->heap()->undefined_value();
}
do {
ZoneList<Variable*> stack_list(outer_scope->StackLocalCount(), zone);
ZoneList<Variable*> context_list(outer_scope->ContextLocalCount(), zone);
outer_scope->CollectStackAndContextLocals(&stack_list, &context_list);
context_list.Sort(&Variable::CompareIndex);
for (int i = 0; i < context_list.length(); i++) {
SetElementNonStrict(scope_info_list,
scope_info_length,
context_list[i]->name());
scope_info_length++;
SetElementNonStrict(
scope_info_list,
scope_info_length,
Handle<Smi>(Smi::FromInt(context_list[i]->index()), isolate()));
scope_info_length++;
}
SetElementNonStrict(scope_info_list,
scope_info_length,
Handle<Object>(isolate()->heap()->null_value(),
isolate()));
scope_info_length++;
outer_scope = outer_scope->outer_scope();
} while (outer_scope != NULL);
return *scope_info_list;
}
Handle<JSArray> result_;
int len_;
int current_parent_index_;
};
JSArray* LiveEdit::GatherCompileInfo(Handle<Script> script,
Handle<String> source) {
Isolate* isolate = Isolate::Current();
FunctionInfoListener listener(isolate);
Handle<Object> original_source =
Handle<Object>(script->source(), isolate);
script->set_source(*source);
isolate->set_active_function_info_listener(&listener);
{
// Creating verbose TryCatch from public API is currently the only way to
// force code save location. We do not use this the object directly.
v8::TryCatch try_catch;
try_catch.SetVerbose(true);
// A logical 'try' section.
CompileScriptForTracker(isolate, script);
}
// A logical 'catch' section.
Handle<JSObject> rethrow_exception;
if (isolate->has_pending_exception()) {
Handle<Object> exception(isolate->pending_exception()->ToObjectChecked(),
isolate);
MessageLocation message_location = isolate->GetMessageLocation();
isolate->clear_pending_message();
isolate->clear_pending_exception();
// If possible, copy positions from message object to exception object.
if (exception->IsJSObject() && !message_location.script().is_null()) {
rethrow_exception = Handle<JSObject>::cast(exception);
Factory* factory = isolate->factory();
Handle<String> start_pos_key = factory->InternalizeOneByteString(
STATIC_ASCII_VECTOR("startPosition"));
Handle<String> end_pos_key = factory->InternalizeOneByteString(
STATIC_ASCII_VECTOR("endPosition"));
Handle<String> script_obj_key = factory->InternalizeOneByteString(
STATIC_ASCII_VECTOR("scriptObject"));
Handle<Smi> start_pos(
Smi::FromInt(message_location.start_pos()), isolate);
Handle<Smi> end_pos(Smi::FromInt(message_location.end_pos()), isolate);
Handle<JSValue> script_obj = GetScriptWrapper(message_location.script());
JSReceiver::SetProperty(
rethrow_exception, start_pos_key, start_pos, NONE, kNonStrictMode);
JSReceiver::SetProperty(
rethrow_exception, end_pos_key, end_pos, NONE, kNonStrictMode);
JSReceiver::SetProperty(
rethrow_exception, script_obj_key, script_obj, NONE, kNonStrictMode);
}
}
// A logical 'finally' section.
isolate->set_active_function_info_listener(NULL);
script->set_source(*original_source);
if (rethrow_exception.is_null()) {
return *(listener.GetResult());
} else {
isolate->Throw(*rethrow_exception);
return 0;
}
}
void LiveEdit::WrapSharedFunctionInfos(Handle<JSArray> array) {
HandleScope scope(array->GetIsolate());
int len = GetArrayLength(array);
for (int i = 0; i < len; i++) {
Handle<SharedFunctionInfo> info(
SharedFunctionInfo::cast(array->GetElementNoExceptionThrown(i)));
SharedInfoWrapper info_wrapper = SharedInfoWrapper::Create();
Handle<String> name_handle(String::cast(info->name()));
info_wrapper.SetProperties(name_handle, info->start_position(),
info->end_position(), info);
SetElementNonStrict(array, i, info_wrapper.GetJSArray());
}
}
// Visitor that finds all references to a particular code object,
// including "CODE_TARGET" references in other code objects and replaces
// them on the fly.
class ReplacingVisitor : public ObjectVisitor {
public:
explicit ReplacingVisitor(Code* original, Code* substitution)
: original_(original), substitution_(substitution) {
}
virtual void VisitPointers(Object** start, Object** end) {
for (Object** p = start; p < end; p++) {
if (*p == original_) {
*p = substitution_;
}
}
}
virtual void VisitCodeEntry(Address entry) {
if (Code::GetObjectFromEntryAddress(entry) == original_) {
Address substitution_entry = substitution_->instruction_start();
Memory::Address_at(entry) = substitution_entry;
}
}
virtual void VisitCodeTarget(RelocInfo* rinfo) {
if (RelocInfo::IsCodeTarget(rinfo->rmode()) &&
Code::GetCodeFromTargetAddress(rinfo->target_address()) == original_) {
Address substitution_entry = substitution_->instruction_start();
rinfo->set_target_address(substitution_entry);
}
}
virtual void VisitDebugTarget(RelocInfo* rinfo) {
VisitCodeTarget(rinfo);
}
private:
Code* original_;
Code* substitution_;
};
// Finds all references to original and replaces them with substitution.
static void ReplaceCodeObject(Handle<Code> original,
Handle<Code> substitution) {
// Perform a full GC in order to ensure that we are not in the middle of an
// incremental marking phase when we are replacing the code object.
// Since we are not in an incremental marking phase we can write pointers
// to code objects (that are never in new space) without worrying about
// write barriers.
Heap* heap = original->GetHeap();
heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
"liveedit.cc ReplaceCodeObject");
ASSERT(!heap->InNewSpace(*substitution));
DisallowHeapAllocation no_allocation;
ReplacingVisitor visitor(*original, *substitution);
// Iterate over all roots. Stack frames may have pointer into original code,
// so temporary replace the pointers with offset numbers
// in prologue/epilogue.
heap->IterateRoots(&visitor, VISIT_ALL);
// Now iterate over all pointers of all objects, including code_target
// implicit pointers.
HeapIterator iterator(heap);
for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
obj->Iterate(&visitor);
}
}
// Patch function literals.
// Name 'literals' is a misnomer. Rather it's a cache for complex object
// boilerplates and for a native context. We must clean cached values.
// Additionally we may need to allocate a new array if number of literals
// changed.
class LiteralFixer {
public:
static void PatchLiterals(FunctionInfoWrapper* compile_info_wrapper,
Handle<SharedFunctionInfo> shared_info,
Isolate* isolate) {
int new_literal_count = compile_info_wrapper->GetLiteralCount();
if (new_literal_count > 0) {
new_literal_count += JSFunction::kLiteralsPrefixSize;
}
int old_literal_count = shared_info->num_literals();
if (old_literal_count == new_literal_count) {
// If literal count didn't change, simply go over all functions
// and clear literal arrays.
ClearValuesVisitor visitor;
IterateJSFunctions(*shared_info, &visitor);
} else {
// When literal count changes, we have to create new array instances.
// Since we cannot create instances when iterating heap, we should first
// collect all functions and fix their literal arrays.
Handle<FixedArray> function_instances =
CollectJSFunctions(shared_info, isolate);
for (int i = 0; i < function_instances->length(); i++) {
Handle<JSFunction> fun(JSFunction::cast(function_instances->get(i)));
Handle<FixedArray> old_literals(fun->literals());
Handle<FixedArray> new_literals =
isolate->factory()->NewFixedArray(new_literal_count);
if (new_literal_count > 0) {
Handle<Context> native_context;
if (old_literals->length() >
JSFunction::kLiteralNativeContextIndex) {
native_context = Handle<Context>(
JSFunction::NativeContextFromLiterals(fun->literals()));
} else {
native_context = Handle<Context>(fun->context()->native_context());
}
new_literals->set(JSFunction::kLiteralNativeContextIndex,
*native_context);
}
fun->set_literals(*new_literals);
}
shared_info->set_num_literals(new_literal_count);
}
}
private:
// Iterates all function instances in the HEAP that refers to the
// provided shared_info.
template<typename Visitor>
static void IterateJSFunctions(SharedFunctionInfo* shared_info,
Visitor* visitor) {
DisallowHeapAllocation no_allocation;
HeapIterator iterator(shared_info->GetHeap());
for (HeapObject* obj = iterator.next(); obj != NULL;
obj = iterator.next()) {
if (obj->IsJSFunction()) {
JSFunction* function = JSFunction::cast(obj);
if (function->shared() == shared_info) {
visitor->visit(function);
}
}
}
}
// Finds all instances of JSFunction that refers to the provided shared_info
// and returns array with them.
static Handle<FixedArray> CollectJSFunctions(
Handle<SharedFunctionInfo> shared_info, Isolate* isolate) {
CountVisitor count_visitor;
count_visitor.count = 0;
IterateJSFunctions(*shared_info, &count_visitor);
int size = count_visitor.count;
Handle<FixedArray> result = isolate->factory()->NewFixedArray(size);
if (size > 0) {
CollectVisitor collect_visitor(result);
IterateJSFunctions(*shared_info, &collect_visitor);
}
return result;
}
class ClearValuesVisitor {
public:
void visit(JSFunction* fun) {
FixedArray* literals = fun->literals();
int len = literals->length();
for (int j = JSFunction::kLiteralsPrefixSize; j < len; j++) {
literals->set_undefined(j);
}
}
};
class CountVisitor {
public:
void visit(JSFunction* fun) {
count++;
}
int count;
};
class CollectVisitor {
public:
explicit CollectVisitor(Handle<FixedArray> output)
: m_output(output), m_pos(0) {}
void visit(JSFunction* fun) {
m_output->set(m_pos, fun);
m_pos++;
}
private:
Handle<FixedArray> m_output;
int m_pos;
};
};
// Check whether the code is natural function code (not a lazy-compile stub
// code).
static bool IsJSFunctionCode(Code* code) {
return code->kind() == Code::FUNCTION;
}
// Returns true if an instance of candidate were inlined into function's code.
static bool IsInlined(JSFunction* function, SharedFunctionInfo* candidate) {
DisallowHeapAllocation no_gc;
if (function->code()->kind() != Code::OPTIMIZED_FUNCTION) return false;
DeoptimizationInputData* data =
DeoptimizationInputData::cast(function->code()->deoptimization_data());
if (data == HEAP->empty_fixed_array()) return false;
FixedArray* literals = data->LiteralArray();
int inlined_count = data->InlinedFunctionCount()->value();
for (int i = 0; i < inlined_count; ++i) {
JSFunction* inlined = JSFunction::cast(literals->get(i));
if (inlined->shared() == candidate) return true;
}
return false;
}
class DependentFunctionFilter : public OptimizedFunctionFilter {
public:
explicit DependentFunctionFilter(
SharedFunctionInfo* function_info)
: function_info_(function_info) {}
virtual bool TakeFunction(JSFunction* function) {
return (function->shared() == function_info_ ||
IsInlined(function, function_info_));
}
private:
SharedFunctionInfo* function_info_;
};
static void DeoptimizeDependentFunctions(SharedFunctionInfo* function_info) {
DisallowHeapAllocation no_allocation;
DependentFunctionFilter filter(function_info);
Deoptimizer::DeoptimizeAllFunctionsWith(function_info->GetIsolate(), &filter);
}
MaybeObject* LiveEdit::ReplaceFunctionCode(
Handle<JSArray> new_compile_info_array,
Handle<JSArray> shared_info_array) {
Isolate* isolate = Isolate::Current();
HandleScope scope(isolate);
if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
return isolate->ThrowIllegalOperation();
}
FunctionInfoWrapper compile_info_wrapper(new_compile_info_array);
SharedInfoWrapper shared_info_wrapper(shared_info_array);
Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
isolate->heap()->EnsureHeapIsIterable();
if (IsJSFunctionCode(shared_info->code())) {
Handle<Code> code = compile_info_wrapper.GetFunctionCode();
ReplaceCodeObject(Handle<Code>(shared_info->code()), code);
Handle<Object> code_scope_info = compile_info_wrapper.GetCodeScopeInfo();
if (code_scope_info->IsFixedArray()) {
shared_info->set_scope_info(ScopeInfo::cast(*code_scope_info));
}
}
if (shared_info->debug_info()->IsDebugInfo()) {
Handle<DebugInfo> debug_info(DebugInfo::cast(shared_info->debug_info()));
Handle<Code> new_original_code =
isolate->factory()->CopyCode(compile_info_wrapper.GetFunctionCode());
debug_info->set_original_code(*new_original_code);
}
int start_position = compile_info_wrapper.GetStartPosition();
int end_position = compile_info_wrapper.GetEndPosition();
shared_info->set_start_position(start_position);
shared_info->set_end_position(end_position);
LiteralFixer::PatchLiterals(&compile_info_wrapper, shared_info, isolate);
shared_info->set_construct_stub(
isolate->builtins()->builtin(Builtins::kJSConstructStubGeneric));
DeoptimizeDependentFunctions(*shared_info);
isolate->compilation_cache()->Remove(shared_info);
return isolate->heap()->undefined_value();
}
MaybeObject* LiveEdit::FunctionSourceUpdated(
Handle<JSArray> shared_info_array) {
Isolate* isolate = shared_info_array->GetIsolate();
HandleScope scope(isolate);
if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
return isolate->ThrowIllegalOperation();
}
SharedInfoWrapper shared_info_wrapper(shared_info_array);
Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
DeoptimizeDependentFunctions(*shared_info);
isolate->compilation_cache()->Remove(shared_info);
return isolate->heap()->undefined_value();
}
void LiveEdit::SetFunctionScript(Handle<JSValue> function_wrapper,
Handle<Object> script_handle) {
Handle<SharedFunctionInfo> shared_info =
UnwrapSharedFunctionInfoFromJSValue(function_wrapper);
CHECK(script_handle->IsScript() || script_handle->IsUndefined());
shared_info->set_script(*script_handle);
Isolate::Current()->compilation_cache()->Remove(shared_info);
}
// For a script text change (defined as position_change_array), translates
// position in unchanged text to position in changed text.
// Text change is a set of non-overlapping regions in text, that have changed
// their contents and length. It is specified as array of groups of 3 numbers:
// (change_begin, change_end, change_end_new_position).
// Each group describes a change in text; groups are sorted by change_begin.
// Only position in text beyond any changes may be successfully translated.
// If a positions is inside some region that changed, result is currently
// undefined.
static int TranslatePosition(int original_position,
Handle<JSArray> position_change_array) {
int position_diff = 0;
int array_len = GetArrayLength(position_change_array);
// TODO(635): binary search may be used here
for (int i = 0; i < array_len; i += 3) {
Object* element = position_change_array->GetElementNoExceptionThrown(i);
CHECK(element->IsSmi());
int chunk_start = Smi::cast(element)->value();
if (original_position < chunk_start) {
break;
}
element = position_change_array->GetElementNoExceptionThrown(i + 1);
CHECK(element->IsSmi());
int chunk_end = Smi::cast(element)->value();
// Position mustn't be inside a chunk.
ASSERT(original_position >= chunk_end);
element = position_change_array->GetElementNoExceptionThrown(i + 2);
CHECK(element->IsSmi());
int chunk_changed_end = Smi::cast(element)->value();
position_diff = chunk_changed_end - chunk_end;
}
return original_position + position_diff;
}
// Auto-growing buffer for writing relocation info code section. This buffer
// is a simplified version of buffer from Assembler. Unlike Assembler, this
// class is platform-independent and it works without dealing with instructions.
// As specified by RelocInfo format, the buffer is filled in reversed order:
// from upper to lower addresses.
// It uses NewArray/DeleteArray for memory management.
class RelocInfoBuffer {
public:
RelocInfoBuffer(int buffer_initial_capicity, byte* pc) {
buffer_size_ = buffer_initial_capicity + kBufferGap;
buffer_ = NewArray<byte>(buffer_size_);
reloc_info_writer_.Reposition(buffer_ + buffer_size_, pc);
}
~RelocInfoBuffer() {
DeleteArray(buffer_);
}
// As specified by RelocInfo format, the buffer is filled in reversed order:
// from upper to lower addresses.
void Write(const RelocInfo* rinfo) {
if (buffer_ + kBufferGap >= reloc_info_writer_.pos()) {
Grow();
}
reloc_info_writer_.Write(rinfo);
}
Vector<byte> GetResult() {
// Return the bytes from pos up to end of buffer.
int result_size =
static_cast<int>((buffer_ + buffer_size_) - reloc_info_writer_.pos());
return Vector<byte>(reloc_info_writer_.pos(), result_size);
}
private:
void Grow() {
// Compute new buffer size.
int new_buffer_size;
if (buffer_size_ < 2 * KB) {
new_buffer_size = 4 * KB;
} else {
new_buffer_size = 2 * buffer_size_;
}
// Some internal data structures overflow for very large buffers,
// they must ensure that kMaximalBufferSize is not too large.
if (new_buffer_size > kMaximalBufferSize) {
V8::FatalProcessOutOfMemory("RelocInfoBuffer::GrowBuffer");
}
// Set up new buffer.
byte* new_buffer = NewArray<byte>(new_buffer_size);
// Copy the data.
int curently_used_size =
static_cast<int>(buffer_ + buffer_size_ - reloc_info_writer_.pos());
OS::MemMove(new_buffer + new_buffer_size - curently_used_size,
reloc_info_writer_.pos(), curently_used_size);
reloc_info_writer_.Reposition(
new_buffer + new_buffer_size - curently_used_size,
reloc_info_writer_.last_pc());
DeleteArray(buffer_);
buffer_ = new_buffer;
buffer_size_ = new_buffer_size;
}
RelocInfoWriter reloc_info_writer_;
byte* buffer_;
int buffer_size_;
static const int kBufferGap = RelocInfoWriter::kMaxSize;
static const int kMaximalBufferSize = 512*MB;
};
// Patch positions in code (changes relocation info section) and possibly
// returns new instance of code.
static Handle<Code> PatchPositionsInCode(
Handle<Code> code,
Handle<JSArray> position_change_array) {
Isolate* isolate = code->GetIsolate();
RelocInfoBuffer buffer_writer(code->relocation_size(),
code->instruction_start());
{
DisallowHeapAllocation no_allocation;
for (RelocIterator it(*code); !it.done(); it.next()) {
RelocInfo* rinfo = it.rinfo();
if (RelocInfo::IsPosition(rinfo->rmode())) {
int position = static_cast<int>(rinfo->data());
int new_position = TranslatePosition(position,
position_change_array);
if (position != new_position) {
RelocInfo info_copy(rinfo->pc(), rinfo->rmode(), new_position, NULL);
buffer_writer.Write(&info_copy);
continue;
}
}
if (RelocInfo::IsRealRelocMode(rinfo->rmode())) {
buffer_writer.Write(it.rinfo());
}
}
}
Vector<byte> buffer = buffer_writer.GetResult();
if (buffer.length() == code->relocation_size()) {
// Simply patch relocation area of code.
OS::MemCopy(code->relocation_start(), buffer.start(), buffer.length());
return code;
} else {
// Relocation info section now has different size. We cannot simply
// rewrite it inside code object. Instead we have to create a new
// code object.
Handle<Code> result(isolate->factory()->CopyCode(code, buffer));
return result;
}
}
MaybeObject* LiveEdit::PatchFunctionPositions(
Handle<JSArray> shared_info_array, Handle<JSArray> position_change_array) {
if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
return Isolate::Current()->ThrowIllegalOperation();
}
SharedInfoWrapper shared_info_wrapper(shared_info_array);
Handle<SharedFunctionInfo> info = shared_info_wrapper.GetInfo();
int old_function_start = info->start_position();
int new_function_start = TranslatePosition(old_function_start,
position_change_array);
int new_function_end = TranslatePosition(info->end_position(),
position_change_array);
int new_function_token_pos =
TranslatePosition(info->function_token_position(), position_change_array);
info->set_start_position(new_function_start);
info->set_end_position(new_function_end);
info->set_function_token_position(new_function_token_pos);
HEAP->EnsureHeapIsIterable();
if (IsJSFunctionCode(info->code())) {
// Patch relocation info section of the code.
Handle<Code> patched_code = PatchPositionsInCode(Handle<Code>(info->code()),
position_change_array);
if (*patched_code != info->code()) {
// Replace all references to the code across the heap. In particular,
// some stubs may refer to this code and this code may be being executed
// on stack (it is safe to substitute the code object on stack, because
// we only change the structure of rinfo and leave instructions
// untouched).
ReplaceCodeObject(Handle<Code>(info->code()), patched_code);
}
}
return HEAP->undefined_value();
}
static Handle<Script> CreateScriptCopy(Handle<Script> original) {
Isolate* isolate = original->GetIsolate();
Handle<String> original_source(String::cast(original->source()));
Handle<Script> copy = isolate->factory()->NewScript(original_source);
copy->set_name(original->name());
copy->set_line_offset(original->line_offset());
copy->set_column_offset(original->column_offset());
copy->set_data(original->data());
copy->set_type(original->type());
copy->set_context_data(original->context_data());
copy->set_compilation_type(original->compilation_type());
copy->set_eval_from_shared(original->eval_from_shared());
copy->set_eval_from_instructions_offset(
original->eval_from_instructions_offset());
return copy;
}
Object* LiveEdit::ChangeScriptSource(Handle<Script> original_script,
Handle<String> new_source,
Handle<Object> old_script_name) {
Isolate* isolate = original_script->GetIsolate();
Handle<Object> old_script_object;
if (old_script_name->IsString()) {
Handle<Script> old_script = CreateScriptCopy(original_script);
old_script->set_name(String::cast(*old_script_name));
old_script_object = old_script;
isolate->debugger()->OnAfterCompile(
old_script, Debugger::SEND_WHEN_DEBUGGING);
} else {
old_script_object = isolate->factory()->null_value();
}
original_script->set_source(*new_source);
// Drop line ends so that they will be recalculated.
original_script->set_line_ends(HEAP->undefined_value());
return *old_script_object;
}
void LiveEdit::ReplaceRefToNestedFunction(
Handle<JSValue> parent_function_wrapper,
Handle<JSValue> orig_function_wrapper,
Handle<JSValue> subst_function_wrapper) {
Handle<SharedFunctionInfo> parent_shared =
UnwrapSharedFunctionInfoFromJSValue(parent_function_wrapper);
Handle<SharedFunctionInfo> orig_shared =
UnwrapSharedFunctionInfoFromJSValue(orig_function_wrapper);
Handle<SharedFunctionInfo> subst_shared =
UnwrapSharedFunctionInfoFromJSValue(subst_function_wrapper);
for (RelocIterator it(parent_shared->code()); !it.done(); it.next()) {
if (it.rinfo()->rmode() == RelocInfo::EMBEDDED_OBJECT) {
if (it.rinfo()->target_object() == *orig_shared) {
it.rinfo()->set_target_object(*subst_shared);
}
}
}
}
// Check an activation against list of functions. If there is a function
// that matches, its status in result array is changed to status argument value.
static bool CheckActivation(Handle<JSArray> shared_info_array,
Handle<JSArray> result,
StackFrame* frame,
LiveEdit::FunctionPatchabilityStatus status) {
if (!frame->is_java_script()) return false;
Handle<JSFunction> function(
JSFunction::cast(JavaScriptFrame::cast(frame)->function()));
Isolate* isolate = shared_info_array->GetIsolate();
int len = GetArrayLength(shared_info_array);
for (int i = 0; i < len; i++) {
Object* element = shared_info_array->GetElementNoExceptionThrown(i);
CHECK(element->IsJSValue());
Handle<JSValue> jsvalue(JSValue::cast(element));
Handle<SharedFunctionInfo> shared =
UnwrapSharedFunctionInfoFromJSValue(jsvalue);
if (function->shared() == *shared || IsInlined(*function, *shared)) {
SetElementNonStrict(result, i, Handle<Smi>(Smi::FromInt(status),
isolate));
return true;
}
}
return false;
}
// Iterates over handler chain and removes all elements that are inside
// frames being dropped.
static bool FixTryCatchHandler(StackFrame* top_frame,
StackFrame* bottom_frame) {
Address* pointer_address =
&Memory::Address_at(Isolate::Current()->get_address_from_id(
Isolate::kHandlerAddress));
while (*pointer_address < top_frame->sp()) {
pointer_address = &Memory::Address_at(*pointer_address);
}
Address* above_frame_address = pointer_address;
while (*pointer_address < bottom_frame->fp()) {
pointer_address = &Memory::Address_at(*pointer_address);
}
bool change = *above_frame_address != *pointer_address;
*above_frame_address = *pointer_address;
return change;
}
// Removes specified range of frames from stack. There may be 1 or more
// frames in range. Anyway the bottom frame is restarted rather than dropped,
// and therefore has to be a JavaScript frame.
// Returns error message or NULL.
static const char* DropFrames(Vector<StackFrame*> frames,
int top_frame_index,
int bottom_js_frame_index,
Debug::FrameDropMode* mode,
Object*** restarter_frame_function_pointer) {
if (!Debug::kFrameDropperSupported) {
return "Stack manipulations are not supported in this architecture.";
}
StackFrame* pre_top_frame = frames[top_frame_index - 1];
StackFrame* top_frame = frames[top_frame_index];
StackFrame* bottom_js_frame = frames[bottom_js_frame_index];
ASSERT(bottom_js_frame->is_java_script());
// Check the nature of the top frame.
Isolate* isolate = Isolate::Current();
Code* pre_top_frame_code = pre_top_frame->LookupCode();
bool frame_has_padding;
if (pre_top_frame_code->is_inline_cache_stub() &&
pre_top_frame_code->is_debug_break()) {
// OK, we can drop inline cache calls.
*mode = Debug::FRAME_DROPPED_IN_IC_CALL;
frame_has_padding = Debug::FramePaddingLayout::kIsSupported;
} else if (pre_top_frame_code ==
isolate->debug()->debug_break_slot()) {
// OK, we can drop debug break slot.
*mode = Debug::FRAME_DROPPED_IN_DEBUG_SLOT_CALL;
frame_has_padding = Debug::FramePaddingLayout::kIsSupported;
} else if (pre_top_frame_code ==
isolate->builtins()->builtin(
Builtins::kFrameDropper_LiveEdit)) {
// OK, we can drop our own code.
pre_top_frame = frames[top_frame_index - 2];
top_frame = frames[top_frame_index - 1];
*mode = Debug::CURRENTLY_SET_MODE;
frame_has_padding = false;
} else if (pre_top_frame_code ==
isolate->builtins()->builtin(Builtins::kReturn_DebugBreak)) {
*mode = Debug::FRAME_DROPPED_IN_RETURN_CALL;
frame_has_padding = Debug::FramePaddingLayout::kIsSupported;
} else if (pre_top_frame_code->kind() == Code::STUB &&
pre_top_frame_code->major_key() == CodeStub::CEntry) {
// Entry from our unit tests on 'debugger' statement.
// It's fine, we support this case.
*mode = Debug::FRAME_DROPPED_IN_DIRECT_CALL;
// We don't have a padding from 'debugger' statement call.
// Here the stub is CEntry, it's not debug-only and can't be padded.
// If anyone would complain, a proxy padded stub could be added.
frame_has_padding = false;
} else if (pre_top_frame->type() == StackFrame::ARGUMENTS_ADAPTOR) {
// This must be adaptor that remain from the frame dropping that
// is still on stack. A frame dropper frame must be above it.
ASSERT(frames[top_frame_index - 2]->LookupCode() ==
isolate->builtins()->builtin(Builtins::kFrameDropper_LiveEdit));
pre_top_frame = frames[top_frame_index - 3];
top_frame = frames[top_frame_index - 2];
*mode = Debug::CURRENTLY_SET_MODE;
frame_has_padding = false;
} else {
return "Unknown structure of stack above changing function";
}
Address unused_stack_top = top_frame->sp();
Address unused_stack_bottom = bottom_js_frame->fp()
- Debug::kFrameDropperFrameSize * kPointerSize // Size of the new frame.
+ kPointerSize; // Bigger address end is exclusive.
Address* top_frame_pc_address = top_frame->pc_address();
// top_frame may be damaged below this point. Do not used it.
ASSERT(!(top_frame = NULL));
if (unused_stack_top > unused_stack_bottom) {
if (frame_has_padding) {
int shortage_bytes =
static_cast<int>(unused_stack_top - unused_stack_bottom);
Address padding_start = pre_top_frame->fp() -
Debug::FramePaddingLayout::kFrameBaseSize * kPointerSize;
Address padding_pointer = padding_start;
Smi* padding_object =
Smi::FromInt(Debug::FramePaddingLayout::kPaddingValue);
while (Memory::Object_at(padding_pointer) == padding_object) {
padding_pointer -= kPointerSize;
}
int padding_counter =
Smi::cast(Memory::Object_at(padding_pointer))->value();
if (padding_counter * kPointerSize < shortage_bytes) {
return "Not enough space for frame dropper frame "
"(even with padding frame)";
}
Memory::Object_at(padding_pointer) =
Smi::FromInt(padding_counter - shortage_bytes / kPointerSize);
StackFrame* pre_pre_frame = frames[top_frame_index - 2];
OS::MemMove(padding_start + kPointerSize - shortage_bytes,
padding_start + kPointerSize,
Debug::FramePaddingLayout::kFrameBaseSize * kPointerSize);
pre_top_frame->UpdateFp(pre_top_frame->fp() - shortage_bytes);
pre_pre_frame->SetCallerFp(pre_top_frame->fp());
unused_stack_top -= shortage_bytes;
STATIC_ASSERT(sizeof(Address) == kPointerSize);
top_frame_pc_address -= shortage_bytes / kPointerSize;
} else {
return "Not enough space for frame dropper frame";
}
}
// Committing now. After this point we should return only NULL value.
FixTryCatchHandler(pre_top_frame, bottom_js_frame);
// Make sure FixTryCatchHandler is idempotent.
ASSERT(!FixTryCatchHandler(pre_top_frame, bottom_js_frame));
Handle<Code> code = Isolate::Current()->builtins()->FrameDropper_LiveEdit();
*top_frame_pc_address = code->entry();
pre_top_frame->SetCallerFp(bottom_js_frame->fp());
*restarter_frame_function_pointer =
Debug::SetUpFrameDropperFrame(bottom_js_frame, code);
ASSERT((**restarter_frame_function_pointer)->IsJSFunction());
for (Address a = unused_stack_top;
a < unused_stack_bottom;
a += kPointerSize) {
Memory::Object_at(a) = Smi::FromInt(0);
}
return NULL;
}
static bool IsDropableFrame(StackFrame* frame) {
return !frame->is_exit();
}
// Describes a set of call frames that execute any of listed functions.
// Finding no such frames does not mean error.
class MultipleFunctionTarget {
public:
MultipleFunctionTarget(Handle<JSArray> shared_info_array,
Handle<JSArray> result)
: m_shared_info_array(shared_info_array),
m_result(result) {}
bool MatchActivation(StackFrame* frame,
LiveEdit::FunctionPatchabilityStatus status) {
return CheckActivation(m_shared_info_array, m_result, frame, status);
}
const char* GetNotFoundMessage() {
return NULL;
}
private:
Handle<JSArray> m_shared_info_array;
Handle<JSArray> m_result;
};
// Drops all call frame matched by target and all frames above them.
template<typename TARGET>
static const char* DropActivationsInActiveThreadImpl(
TARGET& target, bool do_drop, Zone* zone) {
Isolate* isolate = Isolate::Current();
Debug* debug = isolate->debug();
ZoneScope scope(zone, DELETE_ON_EXIT);
Vector<StackFrame*> frames = CreateStackMap(isolate, zone);
int top_frame_index = -1;
int frame_index = 0;
for (; frame_index < frames.length(); frame_index++) {
StackFrame* frame = frames[frame_index];
if (frame->id() == debug->break_frame_id()) {
top_frame_index = frame_index;
break;
}
if (target.MatchActivation(
frame, LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {
// We are still above break_frame. It is not a target frame,
// it is a problem.
return "Debugger mark-up on stack is not found";
}
}
if (top_frame_index == -1) {
// We haven't found break frame, but no function is blocking us anyway.
return target.GetNotFoundMessage();
}
bool target_frame_found = false;
int bottom_js_frame_index = top_frame_index;
bool c_code_found = false;
for (; frame_index < frames.length(); frame_index++) {
StackFrame* frame = frames[frame_index];
if (!IsDropableFrame(frame)) {
c_code_found = true;
break;
}
if (target.MatchActivation(
frame, LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {
target_frame_found = true;
bottom_js_frame_index = frame_index;
}
}
if (c_code_found) {
// There is a C frames on stack. Check that there are no target frames
// below them.
for (; frame_index < frames.length(); frame_index++) {
StackFrame* frame = frames[frame_index];
if (frame->is_java_script()) {
if (target.MatchActivation(
frame, LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {
// Cannot drop frame under C frames.
return NULL;
}
}
}
}
if (!do_drop) {
// We are in check-only mode.
return NULL;
}
if (!target_frame_found) {
// Nothing to drop.
return target.GetNotFoundMessage();
}
Debug::FrameDropMode drop_mode = Debug::FRAMES_UNTOUCHED;
Object** restarter_frame_function_pointer = NULL;
const char* error_message = DropFrames(frames, top_frame_index,
bottom_js_frame_index, &drop_mode,
&restarter_frame_function_pointer);
if (error_message != NULL) {
return error_message;
}
// Adjust break_frame after some frames has been dropped.
StackFrame::Id new_id = StackFrame::NO_ID;
for (int i = bottom_js_frame_index + 1; i < frames.length(); i++) {
if (frames[i]->type() == StackFrame::JAVA_SCRIPT) {
new_id = frames[i]->id();
break;
}
}
debug->FramesHaveBeenDropped(new_id, drop_mode,
restarter_frame_function_pointer);
return NULL;
}
// Fills result array with statuses of functions. Modifies the stack
// removing all listed function if possible and if do_drop is true.
static const char* DropActivationsInActiveThread(
Handle<JSArray> shared_info_array, Handle<JSArray> result, bool do_drop,
Zone* zone) {
MultipleFunctionTarget target(shared_info_array, result);
const char* message =
DropActivationsInActiveThreadImpl(target, do_drop, zone);
if (message) {
return message;
}
Isolate* isolate = shared_info_array->GetIsolate();
int array_len = GetArrayLength(shared_info_array);
// Replace "blocked on active" with "replaced on active" status.
for (int i = 0; i < array_len; i++) {
if (result->GetElement(i) ==
Smi::FromInt(LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {
Handle<Object> replaced(
Smi::FromInt(LiveEdit::FUNCTION_REPLACED_ON_ACTIVE_STACK), isolate);
SetElementNonStrict(result, i, replaced);
}
}
return NULL;
}
class InactiveThreadActivationsChecker : public ThreadVisitor {
public:
InactiveThreadActivationsChecker(Handle<JSArray> shared_info_array,
Handle<JSArray> result)
: shared_info_array_(shared_info_array), result_(result),
has_blocked_functions_(false) {
}
void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
for (StackFrameIterator it(isolate, top); !it.done(); it.Advance()) {
has_blocked_functions_ |= CheckActivation(
shared_info_array_, result_, it.frame(),
LiveEdit::FUNCTION_BLOCKED_ON_OTHER_STACK);
}
}
bool HasBlockedFunctions() {
return has_blocked_functions_;
}
private:
Handle<JSArray> shared_info_array_;
Handle<JSArray> result_;
bool has_blocked_functions_;
};
Handle<JSArray> LiveEdit::CheckAndDropActivations(
Handle<JSArray> shared_info_array, bool do_drop, Zone* zone) {
Isolate* isolate = shared_info_array->GetIsolate();
int len = GetArrayLength(shared_info_array);
Handle<JSArray> result = isolate->factory()->NewJSArray(len);
// Fill the default values.
for (int i = 0; i < len; i++) {
SetElementNonStrict(
result,
i,
Handle<Smi>(Smi::FromInt(FUNCTION_AVAILABLE_FOR_PATCH), isolate));
}
// First check inactive threads. Fail if some functions are blocked there.
InactiveThreadActivationsChecker inactive_threads_checker(shared_info_array,
result);
Isolate::Current()->thread_manager()->IterateArchivedThreads(
&inactive_threads_checker);
if (inactive_threads_checker.HasBlockedFunctions()) {
return result;
}
// Try to drop activations from the current stack.
const char* error_message =
DropActivationsInActiveThread(shared_info_array, result, do_drop, zone);
if (error_message != NULL) {
// Add error message as an array extra element.
Vector<const char> vector_message(error_message, StrLength(error_message));
Handle<String> str = isolate->factory()->NewStringFromAscii(vector_message);
SetElementNonStrict(result, len, str);
}
return result;
}
// Describes a single callframe a target. Not finding this frame
// means an error.
class SingleFrameTarget {
public:
explicit SingleFrameTarget(JavaScriptFrame* frame)
: m_frame(frame),
m_saved_status(LiveEdit::FUNCTION_AVAILABLE_FOR_PATCH) {}
bool MatchActivation(StackFrame* frame,
LiveEdit::FunctionPatchabilityStatus status) {
if (frame->fp() == m_frame->fp()) {
m_saved_status = status;
return true;
}
return false;
}
const char* GetNotFoundMessage() {
return "Failed to found requested frame";
}
LiveEdit::FunctionPatchabilityStatus saved_status() {
return m_saved_status;
}
private:
JavaScriptFrame* m_frame;
LiveEdit::FunctionPatchabilityStatus m_saved_status;
};
// Finds a drops required frame and all frames above.
// Returns error message or NULL.
const char* LiveEdit::RestartFrame(JavaScriptFrame* frame, Zone* zone) {
SingleFrameTarget target(frame);
const char* result = DropActivationsInActiveThreadImpl(target, true, zone);
if (result != NULL) {
return result;
}
if (target.saved_status() == LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE) {
return "Function is blocked under native code";
}
return NULL;
}
LiveEditFunctionTracker::LiveEditFunctionTracker(Isolate* isolate,
FunctionLiteral* fun)
: isolate_(isolate) {
if (isolate_->active_function_info_listener() != NULL) {
isolate_->active_function_info_listener()->FunctionStarted(fun);
}
}
LiveEditFunctionTracker::~LiveEditFunctionTracker() {
if (isolate_->active_function_info_listener() != NULL) {
isolate_->active_function_info_listener()->FunctionDone();
}
}
void LiveEditFunctionTracker::RecordFunctionInfo(
Handle<SharedFunctionInfo> info, FunctionLiteral* lit,
Zone* zone) {
if (isolate_->active_function_info_listener() != NULL) {
isolate_->active_function_info_listener()->FunctionInfo(info, lit->scope(),
zone);
}
}
void LiveEditFunctionTracker::RecordRootFunctionInfo(Handle<Code> code) {
isolate_->active_function_info_listener()->FunctionCode(code);
}
bool LiveEditFunctionTracker::IsActive(Isolate* isolate) {
return isolate->active_function_info_listener() != NULL;
}
#else // ENABLE_DEBUGGER_SUPPORT
// This ifdef-else-endif section provides working or stub implementation of
// LiveEditFunctionTracker.
LiveEditFunctionTracker::LiveEditFunctionTracker(Isolate* isolate,
FunctionLiteral* fun) {
}
LiveEditFunctionTracker::~LiveEditFunctionTracker() {
}
void LiveEditFunctionTracker::RecordFunctionInfo(
Handle<SharedFunctionInfo> info, FunctionLiteral* lit,
Zone* zone) {
}
void LiveEditFunctionTracker::RecordRootFunctionInfo(Handle<Code> code) {
}
bool LiveEditFunctionTracker::IsActive(Isolate* isolate) {
return false;
}
#endif // ENABLE_DEBUGGER_SUPPORT
} } // namespace v8::internal
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