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// Copyright 2006-2008 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 "accessors.h"
#include "ast.h"
#include "deoptimizer.h"
#include "execution.h"
#include "factory.h"
#include "safepoint-table.h"
#include "scopeinfo.h"
#include "top.h"
namespace v8 {
namespace internal {
template <class C>
static C* FindInPrototypeChain(Object* obj, bool* found_it) {
ASSERT(!*found_it);
while (!Is<C>(obj)) {
if (obj == Heap::null_value()) return NULL;
obj = obj->GetPrototype();
}
*found_it = true;
return C::cast(obj);
}
// Entry point that never should be called.
MaybeObject* Accessors::IllegalSetter(JSObject*, Object*, void*) {
UNREACHABLE();
return NULL;
}
Object* Accessors::IllegalGetAccessor(Object* object, void*) {
UNREACHABLE();
return object;
}
MaybeObject* Accessors::ReadOnlySetAccessor(JSObject*, Object* value, void*) {
// According to ECMA-262, section 8.6.2.2, page 28, setting
// read-only properties must be silently ignored.
return value;
}
//
// Accessors::ArrayLength
//
MaybeObject* Accessors::ArrayGetLength(Object* object, void*) {
// Traverse the prototype chain until we reach an array.
bool found_it = false;
JSArray* holder = FindInPrototypeChain<JSArray>(object, &found_it);
if (!found_it) return Smi::FromInt(0);
return holder->length();
}
// The helper function will 'flatten' Number objects.
Object* Accessors::FlattenNumber(Object* value) {
if (value->IsNumber() || !value->IsJSValue()) return value;
JSValue* wrapper = JSValue::cast(value);
ASSERT(
Top::context()->global_context()->number_function()->has_initial_map());
Map* number_map =
Top::context()->global_context()->number_function()->initial_map();
if (wrapper->map() == number_map) return wrapper->value();
return value;
}
MaybeObject* Accessors::ArraySetLength(JSObject* object, Object* value, void*) {
value = FlattenNumber(value);
// Need to call methods that may trigger GC.
HandleScope scope;
// Protect raw pointers.
Handle<JSObject> object_handle(object);
Handle<Object> value_handle(value);
bool has_exception;
Handle<Object> uint32_v = Execution::ToUint32(value_handle, &has_exception);
if (has_exception) return Failure::Exception();
Handle<Object> number_v = Execution::ToNumber(value_handle, &has_exception);
if (has_exception) return Failure::Exception();
// Restore raw pointers,
object = *object_handle;
value = *value_handle;
if (uint32_v->Number() == number_v->Number()) {
if (object->IsJSArray()) {
return JSArray::cast(object)->SetElementsLength(*uint32_v);
} else {
// This means one of the object's prototypes is a JSArray and
// the object does not have a 'length' property.
// Calling SetProperty causes an infinite loop.
return object->SetLocalPropertyIgnoreAttributes(Heap::length_symbol(),
value, NONE);
}
}
return Top::Throw(*Factory::NewRangeError("invalid_array_length",
HandleVector<Object>(NULL, 0)));
}
const AccessorDescriptor Accessors::ArrayLength = {
ArrayGetLength,
ArraySetLength,
0
};
//
// Accessors::StringLength
//
MaybeObject* Accessors::StringGetLength(Object* object, void*) {
Object* value = object;
if (object->IsJSValue()) value = JSValue::cast(object)->value();
if (value->IsString()) return Smi::FromInt(String::cast(value)->length());
// If object is not a string we return 0 to be compatible with WebKit.
// Note: Firefox returns the length of ToString(object).
return Smi::FromInt(0);
}
const AccessorDescriptor Accessors::StringLength = {
StringGetLength,
IllegalSetter,
0
};
//
// Accessors::ScriptSource
//
MaybeObject* Accessors::ScriptGetSource(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->source();
}
const AccessorDescriptor Accessors::ScriptSource = {
ScriptGetSource,
IllegalSetter,
0
};
//
// Accessors::ScriptName
//
MaybeObject* Accessors::ScriptGetName(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->name();
}
const AccessorDescriptor Accessors::ScriptName = {
ScriptGetName,
IllegalSetter,
0
};
//
// Accessors::ScriptId
//
MaybeObject* Accessors::ScriptGetId(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->id();
}
const AccessorDescriptor Accessors::ScriptId = {
ScriptGetId,
IllegalSetter,
0
};
//
// Accessors::ScriptLineOffset
//
MaybeObject* Accessors::ScriptGetLineOffset(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->line_offset();
}
const AccessorDescriptor Accessors::ScriptLineOffset = {
ScriptGetLineOffset,
IllegalSetter,
0
};
//
// Accessors::ScriptColumnOffset
//
MaybeObject* Accessors::ScriptGetColumnOffset(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->column_offset();
}
const AccessorDescriptor Accessors::ScriptColumnOffset = {
ScriptGetColumnOffset,
IllegalSetter,
0
};
//
// Accessors::ScriptData
//
MaybeObject* Accessors::ScriptGetData(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->data();
}
const AccessorDescriptor Accessors::ScriptData = {
ScriptGetData,
IllegalSetter,
0
};
//
// Accessors::ScriptType
//
MaybeObject* Accessors::ScriptGetType(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->type();
}
const AccessorDescriptor Accessors::ScriptType = {
ScriptGetType,
IllegalSetter,
0
};
//
// Accessors::ScriptCompilationType
//
MaybeObject* Accessors::ScriptGetCompilationType(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->compilation_type();
}
const AccessorDescriptor Accessors::ScriptCompilationType = {
ScriptGetCompilationType,
IllegalSetter,
0
};
//
// Accessors::ScriptGetLineEnds
//
MaybeObject* Accessors::ScriptGetLineEnds(Object* object, void*) {
HandleScope scope;
Handle<Script> script(Script::cast(JSValue::cast(object)->value()));
InitScriptLineEnds(script);
ASSERT(script->line_ends()->IsFixedArray());
Handle<FixedArray> line_ends(FixedArray::cast(script->line_ends()));
// We do not want anyone to modify this array from JS.
ASSERT(*line_ends == Heap::empty_fixed_array() ||
line_ends->map() == Heap::fixed_cow_array_map());
Handle<JSArray> js_array = Factory::NewJSArrayWithElements(line_ends);
return *js_array;
}
const AccessorDescriptor Accessors::ScriptLineEnds = {
ScriptGetLineEnds,
IllegalSetter,
0
};
//
// Accessors::ScriptGetContextData
//
MaybeObject* Accessors::ScriptGetContextData(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
return Script::cast(script)->context_data();
}
const AccessorDescriptor Accessors::ScriptContextData = {
ScriptGetContextData,
IllegalSetter,
0
};
//
// Accessors::ScriptGetEvalFromScript
//
MaybeObject* Accessors::ScriptGetEvalFromScript(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
if (!Script::cast(script)->eval_from_shared()->IsUndefined()) {
Handle<SharedFunctionInfo> eval_from_shared(
SharedFunctionInfo::cast(Script::cast(script)->eval_from_shared()));
if (eval_from_shared->script()->IsScript()) {
Handle<Script> eval_from_script(Script::cast(eval_from_shared->script()));
return *GetScriptWrapper(eval_from_script);
}
}
return Heap::undefined_value();
}
const AccessorDescriptor Accessors::ScriptEvalFromScript = {
ScriptGetEvalFromScript,
IllegalSetter,
0
};
//
// Accessors::ScriptGetEvalFromScriptPosition
//
MaybeObject* Accessors::ScriptGetEvalFromScriptPosition(Object* object, void*) {
HandleScope scope;
Handle<Script> script(Script::cast(JSValue::cast(object)->value()));
// If this is not a script compiled through eval there is no eval position.
int compilation_type = Smi::cast(script->compilation_type())->value();
if (compilation_type != Script::COMPILATION_TYPE_EVAL) {
return Heap::undefined_value();
}
// Get the function from where eval was called and find the source position
// from the instruction offset.
Handle<Code> code(SharedFunctionInfo::cast(
script->eval_from_shared())->code());
return Smi::FromInt(code->SourcePosition(code->instruction_start() +
script->eval_from_instructions_offset()->value()));
}
const AccessorDescriptor Accessors::ScriptEvalFromScriptPosition = {
ScriptGetEvalFromScriptPosition,
IllegalSetter,
0
};
//
// Accessors::ScriptGetEvalFromFunctionName
//
MaybeObject* Accessors::ScriptGetEvalFromFunctionName(Object* object, void*) {
Object* script = JSValue::cast(object)->value();
Handle<SharedFunctionInfo> shared(SharedFunctionInfo::cast(
Script::cast(script)->eval_from_shared()));
// Find the name of the function calling eval.
if (!shared->name()->IsUndefined()) {
return shared->name();
} else {
return shared->inferred_name();
}
}
const AccessorDescriptor Accessors::ScriptEvalFromFunctionName = {
ScriptGetEvalFromFunctionName,
IllegalSetter,
0
};
//
// Accessors::FunctionPrototype
//
MaybeObject* Accessors::FunctionGetPrototype(Object* object, void*) {
bool found_it = false;
JSFunction* function = FindInPrototypeChain<JSFunction>(object, &found_it);
if (!found_it) return Heap::undefined_value();
while (!function->should_have_prototype()) {
found_it = false;
function = FindInPrototypeChain<JSFunction>(object->GetPrototype(),
&found_it);
// There has to be one because we hit the getter.
ASSERT(found_it);
}
if (!function->has_prototype()) {
Object* prototype;
{ MaybeObject* maybe_prototype = Heap::AllocateFunctionPrototype(function);
if (!maybe_prototype->ToObject(&prototype)) return maybe_prototype;
}
Object* result;
{ MaybeObject* maybe_result = function->SetPrototype(prototype);
if (!maybe_result->ToObject(&result)) return maybe_result;
}
}
return function->prototype();
}
MaybeObject* Accessors::FunctionSetPrototype(JSObject* object,
Object* value,
void*) {
bool found_it = false;
JSFunction* function = FindInPrototypeChain<JSFunction>(object, &found_it);
if (!found_it) return Heap::undefined_value();
if (!function->should_have_prototype()) {
// Since we hit this accessor, object will have no prototype property.
return object->SetLocalPropertyIgnoreAttributes(Heap::prototype_symbol(),
value,
NONE);
}
if (function->has_initial_map()) {
// If the function has allocated the initial map
// replace it with a copy containing the new prototype.
Object* new_map;
{ MaybeObject* maybe_new_map =
function->initial_map()->CopyDropTransitions();
if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
}
function->set_initial_map(Map::cast(new_map));
}
Object* prototype;
{ MaybeObject* maybe_prototype = function->SetPrototype(value);
if (!maybe_prototype->ToObject(&prototype)) return maybe_prototype;
}
ASSERT(function->prototype() == value);
return function;
}
const AccessorDescriptor Accessors::FunctionPrototype = {
FunctionGetPrototype,
FunctionSetPrototype,
0
};
//
// Accessors::FunctionLength
//
MaybeObject* Accessors::FunctionGetLength(Object* object, void*) {
bool found_it = false;
JSFunction* function = FindInPrototypeChain<JSFunction>(object, &found_it);
if (!found_it) return Smi::FromInt(0);
// Check if already compiled.
if (!function->shared()->is_compiled()) {
// If the function isn't compiled yet, the length is not computed
// correctly yet. Compile it now and return the right length.
HandleScope scope;
Handle<JSFunction> handle(function);
if (!CompileLazy(handle, KEEP_EXCEPTION)) return Failure::Exception();
return Smi::FromInt(handle->shared()->length());
} else {
return Smi::FromInt(function->shared()->length());
}
}
const AccessorDescriptor Accessors::FunctionLength = {
FunctionGetLength,
ReadOnlySetAccessor,
0
};
//
// Accessors::FunctionName
//
MaybeObject* Accessors::FunctionGetName(Object* object, void*) {
bool found_it = false;
JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
if (!found_it) return Heap::undefined_value();
return holder->shared()->name();
}
const AccessorDescriptor Accessors::FunctionName = {
FunctionGetName,
ReadOnlySetAccessor,
0
};
//
// Accessors::FunctionArguments
//
static Address SlotAddress(JavaScriptFrame* frame, int slot_index) {
if (slot_index >= 0) {
const int offset = JavaScriptFrameConstants::kLocal0Offset;
return frame->fp() + offset - (slot_index * kPointerSize);
} else {
const int offset = JavaScriptFrameConstants::kReceiverOffset;
return frame->caller_sp() + offset + (slot_index * kPointerSize);
}
}
// We can't intermix stack decoding and allocations because
// deoptimization infrastracture is not GC safe.
// Thus we build a temporary structure in malloced space.
class SlotRef BASE_EMBEDDED {
public:
enum SlotRepresentation {
UNKNOWN,
TAGGED,
INT32,
DOUBLE,
LITERAL
};
SlotRef()
: addr_(NULL), representation_(UNKNOWN) { }
SlotRef(Address addr, SlotRepresentation representation)
: addr_(addr), representation_(representation) { }
explicit SlotRef(Object* literal)
: literal_(literal), representation_(LITERAL) { }
Handle<Object> GetValue() {
switch (representation_) {
case TAGGED:
return Handle<Object>(Memory::Object_at(addr_));
case INT32: {
int value = Memory::int32_at(addr_);
if (Smi::IsValid(value)) {
return Handle<Object>(Smi::FromInt(value));
} else {
return Factory::NewNumberFromInt(value);
}
}
case DOUBLE: {
double value = Memory::double_at(addr_);
return Factory::NewNumber(value);
}
case LITERAL:
return literal_;
default:
UNREACHABLE();
return Handle<Object>::null();
}
}
private:
Address addr_;
Handle<Object> literal_;
SlotRepresentation representation_;
};
static SlotRef ComputeSlotForNextArgument(TranslationIterator* iterator,
DeoptimizationInputData* data,
JavaScriptFrame* frame) {
Translation::Opcode opcode =
static_cast<Translation::Opcode>(iterator->Next());
switch (opcode) {
case Translation::BEGIN:
case Translation::FRAME:
// Peeled off before getting here.
break;
case Translation::ARGUMENTS_OBJECT:
// This can be only emitted for local slots not for argument slots.
break;
case Translation::REGISTER:
case Translation::INT32_REGISTER:
case Translation::DOUBLE_REGISTER:
case Translation::DUPLICATE:
// We are at safepoint which corresponds to call. All registers are
// saved by caller so there would be no live registers at this
// point. Thus these translation commands should not be used.
break;
case Translation::STACK_SLOT: {
int slot_index = iterator->Next();
Address slot_addr = SlotAddress(frame, slot_index);
return SlotRef(slot_addr, SlotRef::TAGGED);
}
case Translation::INT32_STACK_SLOT: {
int slot_index = iterator->Next();
Address slot_addr = SlotAddress(frame, slot_index);
return SlotRef(slot_addr, SlotRef::INT32);
}
case Translation::DOUBLE_STACK_SLOT: {
int slot_index = iterator->Next();
Address slot_addr = SlotAddress(frame, slot_index);
return SlotRef(slot_addr, SlotRef::DOUBLE);
}
case Translation::LITERAL: {
int literal_index = iterator->Next();
return SlotRef(data->LiteralArray()->get(literal_index));
}
}
UNREACHABLE();
return SlotRef();
}
static void ComputeSlotMappingForArguments(JavaScriptFrame* frame,
int inlined_frame_index,
Vector<SlotRef>* args_slots) {
AssertNoAllocation no_gc;
int deopt_index = AstNode::kNoNumber;
DeoptimizationInputData* data =
static_cast<OptimizedFrame*>(frame)->GetDeoptimizationData(&deopt_index);
TranslationIterator it(data->TranslationByteArray(),
data->TranslationIndex(deopt_index)->value());
Translation::Opcode opcode = static_cast<Translation::Opcode>(it.Next());
ASSERT(opcode == Translation::BEGIN);
int frame_count = it.Next();
USE(frame_count);
ASSERT(frame_count > inlined_frame_index);
int frames_to_skip = inlined_frame_index;
while (true) {
opcode = static_cast<Translation::Opcode>(it.Next());
// Skip over operands to advance to the next opcode.
it.Skip(Translation::NumberOfOperandsFor(opcode));
if (opcode == Translation::FRAME) {
if (frames_to_skip == 0) {
// We reached the frame corresponding to the inlined function
// in question. Process the translation commands for the
// arguments.
//
// Skip the translation command for the receiver.
it.Skip(Translation::NumberOfOperandsFor(
static_cast<Translation::Opcode>(it.Next())));
// Compute slots for arguments.
for (int i = 0; i < args_slots->length(); ++i) {
(*args_slots)[i] = ComputeSlotForNextArgument(&it, data, frame);
}
return;
}
frames_to_skip--;
}
}
UNREACHABLE();
}
static MaybeObject* ConstructArgumentsObjectForInlinedFunction(
JavaScriptFrame* frame,
Handle<JSFunction> inlined_function,
int inlined_frame_index) {
int args_count = inlined_function->shared()->formal_parameter_count();
ScopedVector<SlotRef> args_slots(args_count);
ComputeSlotMappingForArguments(frame, inlined_frame_index, &args_slots);
Handle<JSObject> arguments =
Factory::NewArgumentsObject(inlined_function, args_count);
Handle<FixedArray> array = Factory::NewFixedArray(args_count);
for (int i = 0; i < args_count; ++i) {
Handle<Object> value = args_slots[i].GetValue();
array->set(i, *value);
}
arguments->set_elements(*array);
// Return the freshly allocated arguments object.
return *arguments;
}
MaybeObject* Accessors::FunctionGetArguments(Object* object, void*) {
HandleScope scope;
bool found_it = false;
JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
if (!found_it) return Heap::undefined_value();
Handle<JSFunction> function(holder);
// Find the top invocation of the function by traversing frames.
List<JSFunction*> functions(2);
for (JavaScriptFrameIterator it; !it.done(); it.Advance()) {
JavaScriptFrame* frame = it.frame();
frame->GetFunctions(&functions);
for (int i = functions.length() - 1; i >= 0; i--) {
// Skip all frames that aren't invocations of the given function.
if (functions[i] != *function) continue;
if (i > 0) {
// The function in question was inlined. Inlined functions have the
// correct number of arguments and no allocated arguments object, so
// we can construct a fresh one by interpreting the function's
// deoptimization input data.
return ConstructArgumentsObjectForInlinedFunction(frame, function, i);
}
if (!frame->is_optimized()) {
// If there is an arguments variable in the stack, we return that.
Handle<SerializedScopeInfo> info(function->shared()->scope_info());
int index = info->StackSlotIndex(Heap::arguments_symbol());
if (index >= 0) {
Handle<Object> arguments(frame->GetExpression(index));
if (!arguments->IsArgumentsMarker()) return *arguments;
}
}
// If there is no arguments variable in the stack or we have an
// optimized frame, we find the frame that holds the actual arguments
// passed to the function.
it.AdvanceToArgumentsFrame();
frame = it.frame();
// Get the number of arguments and construct an arguments object
// mirror for the right frame.
const int length = frame->GetProvidedParametersCount();
Handle<JSObject> arguments = Factory::NewArgumentsObject(function,
length);
Handle<FixedArray> array = Factory::NewFixedArray(length);
// Copy the parameters to the arguments object.
ASSERT(array->length() == length);
for (int i = 0; i < length; i++) array->set(i, frame->GetParameter(i));
arguments->set_elements(*array);
// Return the freshly allocated arguments object.
return *arguments;
}
functions.Rewind(0);
}
// No frame corresponding to the given function found. Return null.
return Heap::null_value();
}
const AccessorDescriptor Accessors::FunctionArguments = {
FunctionGetArguments,
ReadOnlySetAccessor,
0
};
//
// Accessors::FunctionCaller
//
MaybeObject* Accessors::FunctionGetCaller(Object* object, void*) {
HandleScope scope;
AssertNoAllocation no_alloc;
bool found_it = false;
JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
if (!found_it) return Heap::undefined_value();
Handle<JSFunction> function(holder);
List<JSFunction*> functions(2);
for (JavaScriptFrameIterator it; !it.done(); it.Advance()) {
JavaScriptFrame* frame = it.frame();
frame->GetFunctions(&functions);
for (int i = functions.length() - 1; i >= 0; i--) {
if (functions[i] == *function) {
// Once we have found the frame, we need to go to the caller
// frame. This may require skipping through a number of top-level
// frames, e.g. frames for scripts not functions.
if (i > 0) {
ASSERT(!functions[i - 1]->shared()->is_toplevel());
return functions[i - 1];
} else {
for (it.Advance(); !it.done(); it.Advance()) {
frame = it.frame();
functions.Rewind(0);
frame->GetFunctions(&functions);
if (!functions.last()->shared()->is_toplevel()) {
return functions.last();
}
ASSERT(functions.length() == 1);
}
if (it.done()) return Heap::null_value();
break;
}
}
}
functions.Rewind(0);
}
// No frame corresponding to the given function found. Return null.
return Heap::null_value();
}
const AccessorDescriptor Accessors::FunctionCaller = {
FunctionGetCaller,
ReadOnlySetAccessor,
0
};
//
// Accessors::ObjectPrototype
//
MaybeObject* Accessors::ObjectGetPrototype(Object* receiver, void*) {
Object* current = receiver->GetPrototype();
while (current->IsJSObject() &&
JSObject::cast(current)->map()->is_hidden_prototype()) {
current = current->GetPrototype();
}
return current;
}
MaybeObject* Accessors::ObjectSetPrototype(JSObject* receiver,
Object* value,
void*) {
const bool skip_hidden_prototypes = true;
// To be consistent with other Set functions, return the value.
return receiver->SetPrototype(value, skip_hidden_prototypes);
}
const AccessorDescriptor Accessors::ObjectPrototype = {
ObjectGetPrototype,
ObjectSetPrototype,
0
};
} } // namespace v8::internal