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// Copyright 2011 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "bootstrapper.h"
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#include "scopeinfo.h"
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Context* Context::declaration_context() {
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Context* current = this;
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while (!current->IsFunctionContext() && !current->IsGlobalContext()) {
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current = current->previous();
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ASSERT(current->closure() == closure());
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JSBuiltinsObject* Context::builtins() {
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GlobalObject* object = global();
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if (object->IsJSGlobalObject()) {
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return JSGlobalObject::cast(object)->builtins();
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ASSERT(object->IsJSBuiltinsObject());
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return JSBuiltinsObject::cast(object);
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Context* Context::global_context() {
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// Fast case: the global object for this context has been set. In
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// that case, the global object has a direct pointer to the global
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if (global()->IsGlobalObject()) {
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return global()->global_context();
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// During bootstrapping, the global object might not be set and we
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// have to search the context chain to find the global context.
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ASSERT(Isolate::Current()->bootstrapper()->IsActive());
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Context* current = this;
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while (!current->IsGlobalContext()) {
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JSFunction* closure = JSFunction::cast(current->closure());
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current = Context::cast(closure->context());
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JSObject* Context::global_proxy() {
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return global_context()->global_proxy_object();
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void Context::set_global_proxy(JSObject* object) {
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global_context()->set_global_proxy_object(object);
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Handle<Object> Context::Lookup(Handle<String> name,
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ContextLookupFlags flags,
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PropertyAttributes* attributes,
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BindingFlags* binding_flags) {
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Isolate* isolate = GetIsolate();
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Handle<Context> context(this, isolate);
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bool follow_context_chain = (flags & FOLLOW_CONTEXT_CHAIN) != 0;
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*binding_flags = MISSING_BINDING;
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if (FLAG_trace_contexts) {
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PrintF("Context::Lookup(");
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if (FLAG_trace_contexts) {
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PrintF(" - looking in context %p", reinterpret_cast<void*>(*context));
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if (context->IsGlobalContext()) PrintF(" (global context)");
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// 1. Check global objects, subjects of with, and extension objects.
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if (context->IsGlobalContext() ||
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context->IsWithContext() ||
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(context->IsFunctionContext() && context->has_extension())) {
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Handle<JSObject> object(JSObject::cast(context->extension()), isolate);
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// Context extension objects needs to behave as if they have no
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// prototype. So even if we want to follow prototype chains, we need
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// to only do a local lookup for context extension objects.
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if ((flags & FOLLOW_PROTOTYPE_CHAIN) == 0 ||
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object->IsJSContextExtensionObject()) {
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*attributes = object->GetLocalPropertyAttribute(*name);
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*attributes = object->GetPropertyAttribute(*name);
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if (*attributes != ABSENT) {
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if (FLAG_trace_contexts) {
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PrintF("=> found property in context object %p\n",
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reinterpret_cast<void*>(*object));
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// 2. Check the context proper if it has slots.
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if (context->IsFunctionContext() || context->IsBlockContext()) {
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// Use serialized scope information of functions and blocks to search
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// for the context index.
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Handle<ScopeInfo> scope_info;
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if (context->IsFunctionContext()) {
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scope_info = Handle<ScopeInfo>(
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context->closure()->shared()->scope_info(), isolate);
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scope_info = Handle<ScopeInfo>(
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ScopeInfo::cast(context->extension()), isolate);
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InitializationFlag init_flag;
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int slot_index = scope_info->ContextSlotIndex(*name, &mode, &init_flag);
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ASSERT(slot_index < 0 || slot_index >= MIN_CONTEXT_SLOTS);
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if (slot_index >= 0) {
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if (FLAG_trace_contexts) {
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PrintF("=> found local in context slot %d (mode = %d)\n",
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// Note: Fixed context slots are statically allocated by the compiler.
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// Statically allocated variables always have a statically known mode,
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// which is the mode with which they were declared when added to the
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// scope. Thus, the DYNAMIC mode (which corresponds to dynamically
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// declared variables that were introduced through declaration nodes)
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// must not appear here.
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case INTERNAL: // Fall through.
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*binding_flags = MUTABLE_IS_INITIALIZED;
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*binding_flags = (init_flag == kNeedsInitialization)
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? MUTABLE_CHECK_INITIALIZED : MUTABLE_IS_INITIALIZED;
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*attributes = READ_ONLY;
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*binding_flags = (init_flag == kNeedsInitialization)
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? IMMUTABLE_CHECK_INITIALIZED : IMMUTABLE_IS_INITIALIZED;
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*attributes = READ_ONLY;
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*binding_flags = (init_flag == kNeedsInitialization)
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? IMMUTABLE_CHECK_INITIALIZED_HARMONY :
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IMMUTABLE_IS_INITIALIZED_HARMONY;
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// Check the slot corresponding to the intermediate context holding
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// only the function name variable.
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if (follow_context_chain && context->IsFunctionContext()) {
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int function_index = scope_info->FunctionContextSlotIndex(*name, &mode);
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if (function_index >= 0) {
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if (FLAG_trace_contexts) {
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PrintF("=> found intermediate function in context slot %d\n",
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*index = function_index;
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*attributes = READ_ONLY;
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ASSERT(mode == CONST || mode == CONST_HARMONY);
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*binding_flags = (mode == CONST)
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? IMMUTABLE_IS_INITIALIZED : IMMUTABLE_IS_INITIALIZED_HARMONY;
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} else if (context->IsCatchContext()) {
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// Catch contexts have the variable name in the extension slot.
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if (name->Equals(String::cast(context->extension()))) {
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if (FLAG_trace_contexts) {
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PrintF("=> found in catch context\n");
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*index = Context::THROWN_OBJECT_INDEX;
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*binding_flags = MUTABLE_IS_INITIALIZED;
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// 3. Prepare to continue with the previous (next outermost) context.
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if (context->IsGlobalContext()) {
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follow_context_chain = false;
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context = Handle<Context>(context->previous(), isolate);
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} while (follow_context_chain);
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if (FLAG_trace_contexts) {
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PrintF("=> no property/slot found\n");
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return Handle<Object>::null();
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void Context::AddOptimizedFunction(JSFunction* function) {
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ASSERT(IsGlobalContext());
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if (FLAG_enable_slow_asserts) {
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Object* element = get(OPTIMIZED_FUNCTIONS_LIST);
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while (!element->IsUndefined()) {
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CHECK(element != function);
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element = JSFunction::cast(element)->next_function_link();
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CHECK(function->next_function_link()->IsUndefined());
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// Check that the context belongs to the weak global contexts list.
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Object* context = GetHeap()->global_contexts_list();
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while (!context->IsUndefined()) {
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if (context == this) {
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context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
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function->set_next_function_link(get(OPTIMIZED_FUNCTIONS_LIST));
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set(OPTIMIZED_FUNCTIONS_LIST, function);
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void Context::RemoveOptimizedFunction(JSFunction* function) {
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ASSERT(IsGlobalContext());
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Object* element = get(OPTIMIZED_FUNCTIONS_LIST);
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JSFunction* prev = NULL;
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while (!element->IsUndefined()) {
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JSFunction* element_function = JSFunction::cast(element);
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ASSERT(element_function->next_function_link()->IsUndefined() ||
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element_function->next_function_link()->IsJSFunction());
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if (element_function == function) {
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set(OPTIMIZED_FUNCTIONS_LIST, element_function->next_function_link());
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prev->set_next_function_link(element_function->next_function_link());
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element_function->set_next_function_link(GetHeap()->undefined_value());
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prev = element_function;
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element = element_function->next_function_link();
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Object* Context::OptimizedFunctionsListHead() {
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ASSERT(IsGlobalContext());
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return get(OPTIMIZED_FUNCTIONS_LIST);
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void Context::ClearOptimizedFunctions() {
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set(OPTIMIZED_FUNCTIONS_LIST, GetHeap()->undefined_value());
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bool Context::IsBootstrappingOrValidParentContext(
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Object* object, Context* child) {
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// During bootstrapping we allow all objects to pass as
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// contexts. This is necessary to fix circular dependencies.
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if (Isolate::Current()->bootstrapper()->IsActive()) return true;
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if (!object->IsContext()) return false;
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Context* context = Context::cast(object);
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return context->IsGlobalContext() || context->IsModuleContext() ||
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!child->IsModuleContext();
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bool Context::IsBootstrappingOrGlobalObject(Object* object) {
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// During bootstrapping we allow all objects to pass as global
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// objects. This is necessary to fix circular dependencies.
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Isolate* isolate = Isolate::Current();
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return isolate->heap()->gc_state() != Heap::NOT_IN_GC ||
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isolate->bootstrapper()->IsActive() ||
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object->IsGlobalObject();
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} } // namespace v8::internal