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blob: 41523a82aa093775aeecd7ee03323cfe14b11a92 [file] [log] [blame]
// Copyright 2010 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 "compiler.h"
#include "oprofile-agent.h"
#include "scopes.h"
#include "scopeinfo.h"
#include "global-handles.h"
#include "debug.h"
#include "memory.h"
namespace v8 {
namespace internal {
#ifdef ENABLE_DEBUGGER_SUPPORT
// 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) {
static StringInputBuffer buf1;
static StringInputBuffer buf2;
buf1.Reset(*s1);
buf1.Seek(pos1);
buf2.Reset(*s2);
buf2.Seek(pos2);
for (int i = 0; i < len; i++) {
ASSERT(buf1.has_more() && buf2.has_more());
if (buf1.GetNext() != buf2.GetNext()) {
return false;
}
}
return true;
}
// 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 Comparator::Input {
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) {
}
int getLength1() {
return line_ends1_.length();
}
int getLength2() {
return line_ends2_.length();
}
bool equals(int index1, int index2) {
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);
}
private:
Handle<String> s1_;
Handle<String> s2_;
LineEndsWrapper line_ends1_;
LineEndsWrapper line_ends2_;
};
// Stores compare result in JSArray. Each chunk is stored as 3 array elements:
// (pos1_begin, pos1_end, pos2_end).
class LineArrayCompareOutput : public Comparator::Output {
public:
LineArrayCompareOutput(LineEndsWrapper line_ends1, LineEndsWrapper line_ends2)
: array_(Factory::NewJSArray(10)), current_size_(0),
line_ends1_(line_ends1), line_ends2_(line_ends2) {
}
void AddChunk(int line_pos1, int line_pos2, int line_len1, int line_len2) {
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;
SetElement(array_, current_size_, Handle<Object>(Smi::FromInt(char_pos1)));
SetElement(array_, current_size_ + 1,
Handle<Object>(Smi::FromInt(char_pos1 + char_len1)));
SetElement(array_, current_size_ + 2,
Handle<Object>(Smi::FromInt(char_pos2 + char_len2)));
current_size_ += 3;
}
Handle<JSArray> GetResult() {
return array_;
}
private:
Handle<JSArray> array_;
int current_size_;
LineEndsWrapper line_ends1_;
LineEndsWrapper line_ends2_;
};
Handle<JSArray> LiveEdit::CompareStringsLinewise(Handle<String> s1,
Handle<String> s2) {
LineEndsWrapper line_ends1(s1);
LineEndsWrapper line_ends2(s2);
LineArrayCompareInput input(s1, s2, line_ends1, line_ends2);
LineArrayCompareOutput output(line_ends1, line_ends2);
Comparator::CalculateDifference(&input, &output);
return output.GetResult();
}
static void CompileScriptForTracker(Handle<Script> script) {
const bool is_eval = false;
const bool is_global = true;
// TODO(635): support extensions.
Extension* extension = NULL;
PostponeInterruptsScope postpone;
// Only allow non-global compiles for eval.
ASSERT(is_eval || is_global);
// Build AST.
ScriptDataImpl* pre_data = NULL;
FunctionLiteral* lit = MakeAST(is_global, script, extension, pre_data);
// Check for parse errors.
if (lit == NULL) {
ASSERT(Top::has_pending_exception());
return;
}
// Compile the code.
CompilationInfo info(lit, script, is_eval);
LiveEditFunctionTracker tracker(lit);
Handle<Code> code = MakeCodeForLiveEdit(&info);
// Check for stack-overflow exceptions.
if (code.is_null()) {
Top::StackOverflow();
return;
}
tracker.RecordRootFunctionInfo(code);
}
// Unwraps JSValue object, returning its field "value"
static Handle<Object> UnwrapJSValue(Handle<JSValue> jsValue) {
return Handle<Object>(jsValue->value());
}
// Wraps any object into a OpaqueReference, that will hide the object
// from JavaScript.
static Handle<JSValue> WrapInJSValue(Object* object) {
Handle<JSFunction> constructor = Top::opaque_reference_function();
Handle<JSValue> result =
Handle<JSValue>::cast(Factory::NewJSObject(constructor));
result->set_value(object);
return result;
}
// 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() {
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_;
}
protected:
void SetField(int field_position, Handle<Object> value) {
SetElement(array_, field_position, value);
}
void SetSmiValueField(int field_position, int value) {
SetElement(array_, field_position, Handle<Smi>(Smi::FromInt(value)));
}
Object* GetField(int field_position) {
return array_->GetElement(field_position);
}
int GetSmiValueField(int field_position) {
Object* res = GetField(field_position);
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 parent_index) {
HandleScope scope;
this->SetField(kFunctionNameOffset_, name);
this->SetSmiValueField(kStartPositionOffset_, start_position);
this->SetSmiValueField(kEndPositionOffset_, end_position);
this->SetSmiValueField(kParamNumOffset_, param_num);
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 GetParentIndex() {
return this->GetSmiValueField(kParentIndexOffset_);
}
Handle<Code> GetFunctionCode() {
Handle<Object> raw_result = UnwrapJSValue(Handle<JSValue>(
JSValue::cast(this->GetField(kCodeOffset_))));
return Handle<Code>::cast(raw_result);
}
Handle<Object> GetCodeScopeInfo() {
Handle<Object> raw_result = UnwrapJSValue(Handle<JSValue>(
JSValue::cast(this->GetField(kCodeScopeInfoOffset_))));
return raw_result;
}
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 kSize_ = 9;
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->GetElement(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;
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_);
Handle<JSValue> value_wrapper(JSValue::cast(element));
Handle<Object> raw_result = UnwrapJSValue(value_wrapper);
return Handle<SharedFunctionInfo>::cast(raw_result);
}
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:
FunctionInfoListener() {
current_parent_index_ = -1;
len_ = 0;
result_ = Factory::NewJSArray(10);
}
void FunctionStarted(FunctionLiteral* fun) {
HandleScope scope;
FunctionInfoWrapper info = FunctionInfoWrapper::Create();
info.SetInitialProperties(fun->name(), fun->start_position(),
fun->end_position(), fun->num_parameters(),
current_parent_index_);
current_parent_index_ = len_;
SetElement(result_, len_, info.GetJSArray());
len_++;
}
void FunctionDone() {
HandleScope scope;
FunctionInfoWrapper info =
FunctionInfoWrapper::cast(result_->GetElement(current_parent_index_));
current_parent_index_ = info.GetParentIndex();
}
public:
// 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_->GetElement(current_parent_index_));
info.SetFunctionCode(function_code, Handle<Object>(Heap::null_value()));
}
// Saves full information about a function: its code, its scope info
// and a SharedFunctionInfo object.
void FunctionInfo(Handle<SharedFunctionInfo> shared, Scope* scope) {
if (!shared->IsSharedFunctionInfo()) {
return;
}
FunctionInfoWrapper info =
FunctionInfoWrapper::cast(result_->GetElement(current_parent_index_));
info.SetFunctionCode(Handle<Code>(shared->code()),
Handle<Object>(shared->scope_info()));
info.SetSharedFunctionInfo(shared);
Handle<Object> scope_info_list(SerializeFunctionScope(scope));
info.SetOuterScopeInfo(scope_info_list);
}
Handle<JSArray> GetResult() { return result_; }
private:
Object* SerializeFunctionScope(Scope* scope) {
HandleScope handle_scope;
Handle<JSArray> scope_info_list = 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 Heap::undefined_value();
}
do {
ZoneList<Variable*> list(10);
outer_scope->CollectUsedVariables(&list);
int j = 0;
for (int i = 0; i < list.length(); i++) {
Variable* var1 = list[i];
Slot* slot = var1->slot();
if (slot != NULL && slot->type() == Slot::CONTEXT) {
if (j != i) {
list[j] = var1;
}
j++;
}
}
// Sort it.
for (int k = 1; k < j; k++) {
int l = k;
for (int m = k + 1; m < j; m++) {
if (list[l]->slot()->index() > list[m]->slot()->index()) {
l = m;
}
}
list[k] = list[l];
}
for (int i = 0; i < j; i++) {
SetElement(scope_info_list, scope_info_length, list[i]->name());
scope_info_length++;
SetElement(scope_info_list, scope_info_length,
Handle<Smi>(Smi::FromInt(list[i]->slot()->index())));
scope_info_length++;
}
SetElement(scope_info_list, scope_info_length,
Handle<Object>(Heap::null_value()));
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_;
};
static FunctionInfoListener* active_function_info_listener = NULL;
JSArray* LiveEdit::GatherCompileInfo(Handle<Script> script,
Handle<String> source) {
CompilationZoneScope zone_scope(DELETE_ON_EXIT);
FunctionInfoListener listener;
Handle<Object> original_source = Handle<Object>(script->source());
script->set_source(*source);
active_function_info_listener = &listener;
CompileScriptForTracker(script);
active_function_info_listener = NULL;
script->set_source(*original_source);
return *(listener.GetResult());
}
void LiveEdit::WrapSharedFunctionInfos(Handle<JSArray> array) {
HandleScope scope;
int len = Smi::cast(array->length())->value();
for (int i = 0; i < len; i++) {
Handle<SharedFunctionInfo> info(
SharedFunctionInfo::cast(array->GetElement(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);
SetElement(array, i, info_wrapper.GetJSArray());
}
}
// Visitor that collects all references to a particular code object,
// including "CODE_TARGET" references in other code objects.
// It works in context of ZoneScope.
class ReferenceCollectorVisitor : public ObjectVisitor {
public:
explicit ReferenceCollectorVisitor(Code* original)
: original_(original), rvalues_(10), reloc_infos_(10), code_entries_(10) {
}
virtual void VisitPointers(Object** start, Object** end) {
for (Object** p = start; p < end; p++) {
if (*p == original_) {
rvalues_.Add(p);
}
}
}
virtual void VisitCodeEntry(Address entry) {
if (Code::GetObjectFromEntryAddress(entry) == original_) {
code_entries_.Add(entry);
}
}
virtual void VisitCodeTarget(RelocInfo* rinfo) {
if (RelocInfo::IsCodeTarget(rinfo->rmode()) &&
Code::GetCodeFromTargetAddress(rinfo->target_address()) == original_) {
reloc_infos_.Add(*rinfo);
}
}
virtual void VisitDebugTarget(RelocInfo* rinfo) {
VisitCodeTarget(rinfo);
}
// Post-visiting method that iterates over all collected references and
// modifies them.
void Replace(Code* substitution) {
for (int i = 0; i < rvalues_.length(); i++) {
*(rvalues_[i]) = substitution;
}
Address substitution_entry = substitution->instruction_start();
for (int i = 0; i < reloc_infos_.length(); i++) {
reloc_infos_[i].set_target_address(substitution_entry);
}
for (int i = 0; i < code_entries_.length(); i++) {
Address entry = code_entries_[i];
Memory::Address_at(entry) = substitution_entry;
}
}
private:
Code* original_;
ZoneList<Object**> rvalues_;
ZoneList<RelocInfo> reloc_infos_;
ZoneList<Address> code_entries_;
};
// Finds all references to original and replaces them with substitution.
static void ReplaceCodeObject(Code* original, Code* substitution) {
ASSERT(!Heap::InNewSpace(substitution));
AssertNoAllocation no_allocations_please;
// A zone scope for ReferenceCollectorVisitor.
ZoneScope scope(DELETE_ON_EXIT);
ReferenceCollectorVisitor visitor(original);
// Iterate over all roots. Stack frames may have pointer into original code,
// so temporary replace the pointers with offset numbers
// in prologue/epilogue.
{
Heap::IterateStrongRoots(&visitor, VISIT_ALL);
}
// Now iterate over all pointers of all objects, including code_target
// implicit pointers.
HeapIterator iterator;
for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
obj->Iterate(&visitor);
}
visitor.Replace(substitution);
}
// Check whether the code is natural function code (not a lazy-compile stub
// code).
static bool IsJSFunctionCode(Code* code) {
return code->kind() == Code::FUNCTION;
}
Object* LiveEdit::ReplaceFunctionCode(Handle<JSArray> new_compile_info_array,
Handle<JSArray> shared_info_array) {
HandleScope scope;
if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
return Top::ThrowIllegalOperation();
}
FunctionInfoWrapper compile_info_wrapper(new_compile_info_array);
SharedInfoWrapper shared_info_wrapper(shared_info_array);
Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
if (IsJSFunctionCode(shared_info->code())) {
ReplaceCodeObject(shared_info->code(),
*(compile_info_wrapper.GetFunctionCode()));
Handle<Object> code_scope_info = compile_info_wrapper.GetCodeScopeInfo();
if (code_scope_info->IsFixedArray()) {
shared_info->set_scope_info(SerializedScopeInfo::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 =
Factory::CopyCode(compile_info_wrapper.GetFunctionCode());
debug_info->set_original_code(*new_original_code);
}
shared_info->set_start_position(compile_info_wrapper.GetStartPosition());
shared_info->set_end_position(compile_info_wrapper.GetEndPosition());
shared_info->set_construct_stub(
Builtins::builtin(Builtins::JSConstructStubGeneric));
return Heap::undefined_value();
}
// TODO(635): Eval caches its scripts (same text -- same compiled info).
// Make sure we clear such caches.
void LiveEdit::SetFunctionScript(Handle<JSValue> function_wrapper,
Handle<Object> script_handle) {
Handle<SharedFunctionInfo> shared_info =
Handle<SharedFunctionInfo>::cast(UnwrapJSValue(function_wrapper));
shared_info->set_script(*script_handle);
}
// 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 = Smi::cast(position_change_array->length())->value();
// TODO(635): binary search may be used here
for (int i = 0; i < array_len; i += 3) {
int chunk_start =
Smi::cast(position_change_array->GetElement(i))->value();
if (original_position < chunk_start) {
break;
}
int chunk_end =
Smi::cast(position_change_array->GetElement(i + 1))->value();
// Position mustn't be inside a chunk.
ASSERT(original_position >= chunk_end);
int chunk_changed_end =
Smi::cast(position_change_array->GetElement(i + 2))->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");
}
// Setup 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());
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) {
RelocInfoBuffer buffer_writer(code->relocation_size(),
code->instruction_start());
{
AssertNoAllocation no_allocations_please;
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);
buffer_writer.Write(&info_copy);
continue;
}
}
buffer_writer.Write(it.rinfo());
}
}
Vector<byte> buffer = buffer_writer.GetResult();
if (buffer.length() == code->relocation_size()) {
// Simply patch relocation area of code.
memcpy(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(Factory::CopyCode(code, buffer));
return result;
}
}
Object* LiveEdit::PatchFunctionPositions(
Handle<JSArray> shared_info_array, Handle<JSArray> position_change_array) {
if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
return Top::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);
info->set_start_position(new_function_start);
info->set_end_position(TranslatePosition(info->end_position(),
position_change_array));
info->set_function_token_position(
TranslatePosition(info->function_token_position(),
position_change_array));
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(info->code(), *patched_code);
}
}
return Heap::undefined_value();
}
static Handle<Script> CreateScriptCopy(Handle<Script> original) {
Handle<String> original_source(String::cast(original->source()));
Handle<Script> copy = 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) {
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;
Debugger::OnAfterCompile(old_script, Debugger::SEND_WHEN_DEBUGGING);
} else {
old_script_object = Handle<Object>(Heap::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 =
Handle<SharedFunctionInfo>::cast(UnwrapJSValue(parent_function_wrapper));
Handle<SharedFunctionInfo> orig_shared =
Handle<SharedFunctionInfo>::cast(UnwrapJSValue(orig_function_wrapper));
Handle<SharedFunctionInfo> subst_shared =
Handle<SharedFunctionInfo>::cast(UnwrapJSValue(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;
}
int len = Smi::cast(shared_info_array->length())->value();
for (int i = 0; i < len; i++) {
JSValue* wrapper = JSValue::cast(shared_info_array->GetElement(i));
Handle<SharedFunctionInfo> shared(
SharedFunctionInfo::cast(wrapper->value()));
if (frame->code() == shared->code()) {
SetElement(result, i, Handle<Smi>(Smi::FromInt(status)));
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(Top::get_address_from_id(Top::k_handler_address));
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.
if (pre_top_frame->code()->is_inline_cache_stub() &&
pre_top_frame->code()->ic_state() == DEBUG_BREAK) {
// OK, we can drop inline cache calls.
*mode = Debug::FRAME_DROPPED_IN_IC_CALL;
} else if (pre_top_frame->code() == Debug::debug_break_slot()) {
// OK, we can drop debug break slot.
*mode = Debug::FRAME_DROPPED_IN_DEBUG_SLOT_CALL;
} else if (pre_top_frame->code() ==
Builtins::builtin(Builtins::FrameDropper_LiveEdit)) {
// OK, we can drop our own code.
*mode = Debug::FRAME_DROPPED_IN_DIRECT_CALL;
} else if (pre_top_frame->code()->kind() == Code::STUB &&
pre_top_frame->code()->major_key()) {
// Entry from our unit tests, it's fine, we support this case.
*mode = Debug::FRAME_DROPPED_IN_DIRECT_CALL;
} 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.
if (unused_stack_top > unused_stack_bottom) {
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(Builtins::builtin(Builtins::FrameDropper_LiveEdit));
top_frame->set_pc(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();
}
// 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) {
ZoneScope scope(DELETE_ON_EXIT);
Vector<StackFrame*> frames = CreateStackMap();
int array_len = Smi::cast(shared_info_array->length())->value();
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 (CheckActivation(shared_info_array, result, 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 NULL;
}
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 (CheckActivation(shared_info_array, result, 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 (CheckActivation(shared_info_array, result, 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 NULL;
}
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);
// 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));
SetElement(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(ThreadLocalTop* top) {
for (StackFrameIterator it(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) {
int len = Smi::cast(shared_info_array->length())->value();
Handle<JSArray> result = Factory::NewJSArray(len);
// Fill the default values.
for (int i = 0; i < len; i++) {
SetElement(result, i,
Handle<Smi>(Smi::FromInt(FUNCTION_AVAILABLE_FOR_PATCH)));
}
// First check inactive threads. Fail if some functions are blocked there.
InactiveThreadActivationsChecker inactive_threads_checker(shared_info_array,
result);
ThreadManager::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);
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 = Factory::NewStringFromAscii(vector_message);
SetElement(result, len, str);
}
return result;
}
LiveEditFunctionTracker::LiveEditFunctionTracker(FunctionLiteral* fun) {
if (active_function_info_listener != NULL) {
active_function_info_listener->FunctionStarted(fun);
}
}
LiveEditFunctionTracker::~LiveEditFunctionTracker() {
if (active_function_info_listener != NULL) {
active_function_info_listener->FunctionDone();
}
}
void LiveEditFunctionTracker::RecordFunctionInfo(
Handle<SharedFunctionInfo> info, FunctionLiteral* lit) {
if (active_function_info_listener != NULL) {
active_function_info_listener->FunctionInfo(info, lit->scope());
}
}
void LiveEditFunctionTracker::RecordRootFunctionInfo(Handle<Code> code) {
active_function_info_listener->FunctionCode(code);
}
bool LiveEditFunctionTracker::IsActive() {
return active_function_info_listener != NULL;
}
#else // ENABLE_DEBUGGER_SUPPORT
// This ifdef-else-endif section provides working or stub implementation of
// LiveEditFunctionTracker.
LiveEditFunctionTracker::LiveEditFunctionTracker(FunctionLiteral* fun) {
}
LiveEditFunctionTracker::~LiveEditFunctionTracker() {
}
void LiveEditFunctionTracker::RecordFunctionInfo(
Handle<SharedFunctionInfo> info, FunctionLiteral* lit) {
}
void LiveEditFunctionTracker::RecordRootFunctionInfo(Handle<Code> code) {
}
bool LiveEditFunctionTracker::IsActive() {
return false;
}
#endif // ENABLE_DEBUGGER_SUPPORT
} } // namespace v8::internal