| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/contexts.h" |
| |
| #include "src/ast/modules.h" |
| #include "src/bootstrapper.h" |
| #include "src/debug/debug.h" |
| #include "src/isolate-inl.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| Handle<ScriptContextTable> ScriptContextTable::Extend( |
| Handle<ScriptContextTable> table, Handle<Context> script_context) { |
| Handle<ScriptContextTable> result; |
| int used = table->used(); |
| int length = table->length(); |
| CHECK(used >= 0 && length > 0 && used < length); |
| if (used + kFirstContextSlotIndex == length) { |
| CHECK(length < Smi::kMaxValue / 2); |
| Isolate* isolate = table->GetIsolate(); |
| Handle<FixedArray> copy = |
| isolate->factory()->CopyFixedArrayAndGrow(table, length); |
| copy->set_map(isolate->heap()->script_context_table_map()); |
| result = Handle<ScriptContextTable>::cast(copy); |
| } else { |
| result = table; |
| } |
| result->set_used(used + 1); |
| |
| DCHECK(script_context->IsScriptContext()); |
| result->set(used + kFirstContextSlotIndex, *script_context); |
| return result; |
| } |
| |
| |
| bool ScriptContextTable::Lookup(Handle<ScriptContextTable> table, |
| Handle<String> name, LookupResult* result) { |
| for (int i = 0; i < table->used(); i++) { |
| Handle<Context> context = GetContext(table, i); |
| DCHECK(context->IsScriptContext()); |
| Handle<ScopeInfo> scope_info(context->scope_info()); |
| int slot_index = ScopeInfo::ContextSlotIndex( |
| scope_info, name, &result->mode, &result->init_flag, |
| &result->maybe_assigned_flag); |
| |
| if (slot_index >= 0) { |
| result->context_index = i; |
| result->slot_index = slot_index; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| bool Context::is_declaration_context() { |
| if (IsFunctionContext() || IsNativeContext() || IsScriptContext() || |
| IsModuleContext()) { |
| return true; |
| } |
| if (IsEvalContext()) |
| return closure()->shared()->language_mode() == LanguageMode::kStrict; |
| if (!IsBlockContext()) return false; |
| Object* ext = extension(); |
| // If we have the special extension, we immediately know it must be a |
| // declaration scope. That's just a small performance shortcut. |
| return ext->IsContextExtension() || |
| ScopeInfo::cast(ext)->is_declaration_scope(); |
| } |
| |
| |
| Context* Context::declaration_context() { |
| Context* current = this; |
| while (!current->is_declaration_context()) { |
| current = current->previous(); |
| } |
| return current; |
| } |
| |
| Context* Context::closure_context() { |
| Context* current = this; |
| while (!current->IsFunctionContext() && !current->IsScriptContext() && |
| !current->IsModuleContext() && !current->IsNativeContext() && |
| !current->IsEvalContext()) { |
| current = current->previous(); |
| DCHECK(current->closure() == closure()); |
| } |
| return current; |
| } |
| |
| JSObject* Context::extension_object() { |
| DCHECK(IsNativeContext() || IsFunctionContext() || IsBlockContext() || |
| IsEvalContext()); |
| HeapObject* object = extension(); |
| if (object->IsTheHole(GetIsolate())) return nullptr; |
| if (IsBlockContext()) { |
| if (!object->IsContextExtension()) return nullptr; |
| object = JSObject::cast(ContextExtension::cast(object)->extension()); |
| } |
| DCHECK(object->IsJSContextExtensionObject() || |
| (IsNativeContext() && object->IsJSGlobalObject())); |
| return JSObject::cast(object); |
| } |
| |
| JSReceiver* Context::extension_receiver() { |
| DCHECK(IsNativeContext() || IsWithContext() || IsEvalContext() || |
| IsFunctionContext() || IsBlockContext()); |
| return IsWithContext() ? JSReceiver::cast( |
| ContextExtension::cast(extension())->extension()) |
| : extension_object(); |
| } |
| |
| ScopeInfo* Context::scope_info() { |
| DCHECK(!IsNativeContext()); |
| if (IsFunctionContext() || IsModuleContext() || IsEvalContext()) { |
| return closure()->shared()->scope_info(); |
| } |
| HeapObject* object = extension(); |
| if (object->IsContextExtension()) { |
| DCHECK(IsBlockContext() || IsCatchContext() || IsWithContext() || |
| IsDebugEvaluateContext()); |
| object = ContextExtension::cast(object)->scope_info(); |
| } |
| return ScopeInfo::cast(object); |
| } |
| |
| Module* Context::module() { |
| Context* current = this; |
| while (!current->IsModuleContext()) { |
| current = current->previous(); |
| } |
| return Module::cast(current->extension()); |
| } |
| |
| String* Context::catch_name() { |
| DCHECK(IsCatchContext()); |
| return String::cast(ContextExtension::cast(extension())->extension()); |
| } |
| |
| |
| JSGlobalObject* Context::global_object() { |
| return JSGlobalObject::cast(native_context()->extension()); |
| } |
| |
| |
| Context* Context::script_context() { |
| Context* current = this; |
| while (!current->IsScriptContext()) { |
| current = current->previous(); |
| } |
| return current; |
| } |
| |
| |
| JSObject* Context::global_proxy() { |
| return native_context()->global_proxy_object(); |
| } |
| |
| |
| void Context::set_global_proxy(JSObject* object) { |
| native_context()->set_global_proxy_object(object); |
| } |
| |
| |
| /** |
| * Lookups a property in an object environment, taking the unscopables into |
| * account. This is used For HasBinding spec algorithms for ObjectEnvironment. |
| */ |
| static Maybe<bool> UnscopableLookup(LookupIterator* it) { |
| Isolate* isolate = it->isolate(); |
| |
| Maybe<bool> found = JSReceiver::HasProperty(it); |
| if (found.IsNothing() || !found.FromJust()) return found; |
| |
| Handle<Object> unscopables; |
| ASSIGN_RETURN_ON_EXCEPTION_VALUE( |
| isolate, unscopables, |
| JSReceiver::GetProperty(Handle<JSReceiver>::cast(it->GetReceiver()), |
| isolate->factory()->unscopables_symbol()), |
| Nothing<bool>()); |
| if (!unscopables->IsJSReceiver()) return Just(true); |
| Handle<Object> blacklist; |
| ASSIGN_RETURN_ON_EXCEPTION_VALUE( |
| isolate, blacklist, |
| JSReceiver::GetProperty(Handle<JSReceiver>::cast(unscopables), |
| it->name()), |
| Nothing<bool>()); |
| return Just(!blacklist->BooleanValue()); |
| } |
| |
| static PropertyAttributes GetAttributesForMode(VariableMode mode) { |
| DCHECK(IsDeclaredVariableMode(mode)); |
| return mode == CONST ? READ_ONLY : NONE; |
| } |
| |
| Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags, |
| int* index, PropertyAttributes* attributes, |
| InitializationFlag* init_flag, |
| VariableMode* variable_mode, |
| bool* is_sloppy_function_name) { |
| Isolate* isolate = GetIsolate(); |
| Handle<Context> context(this, isolate); |
| |
| bool follow_context_chain = (flags & FOLLOW_CONTEXT_CHAIN) != 0; |
| bool failed_whitelist = false; |
| *index = kNotFound; |
| *attributes = ABSENT; |
| *init_flag = kCreatedInitialized; |
| *variable_mode = VAR; |
| if (is_sloppy_function_name != nullptr) { |
| *is_sloppy_function_name = false; |
| } |
| |
| if (FLAG_trace_contexts) { |
| PrintF("Context::Lookup("); |
| name->ShortPrint(); |
| PrintF(")\n"); |
| } |
| |
| do { |
| if (FLAG_trace_contexts) { |
| PrintF(" - looking in context %p", reinterpret_cast<void*>(*context)); |
| if (context->IsScriptContext()) PrintF(" (script context)"); |
| if (context->IsNativeContext()) PrintF(" (native context)"); |
| PrintF("\n"); |
| } |
| |
| // 1. Check global objects, subjects of with, and extension objects. |
| DCHECK_IMPLIES(context->IsEvalContext(), |
| context->extension()->IsTheHole(isolate)); |
| if ((context->IsNativeContext() || |
| (context->IsWithContext() && ((flags & SKIP_WITH_CONTEXT) == 0)) || |
| context->IsFunctionContext() || context->IsBlockContext()) && |
| context->extension_receiver() != nullptr) { |
| Handle<JSReceiver> object(context->extension_receiver()); |
| |
| if (context->IsNativeContext()) { |
| if (FLAG_trace_contexts) { |
| PrintF(" - trying other script contexts\n"); |
| } |
| // Try other script contexts. |
| Handle<ScriptContextTable> script_contexts( |
| context->global_object()->native_context()->script_context_table()); |
| ScriptContextTable::LookupResult r; |
| if (ScriptContextTable::Lookup(script_contexts, name, &r)) { |
| if (FLAG_trace_contexts) { |
| Handle<Context> c = ScriptContextTable::GetContext(script_contexts, |
| r.context_index); |
| PrintF("=> found property in script context %d: %p\n", |
| r.context_index, reinterpret_cast<void*>(*c)); |
| } |
| *index = r.slot_index; |
| *variable_mode = r.mode; |
| *init_flag = r.init_flag; |
| *attributes = GetAttributesForMode(r.mode); |
| return ScriptContextTable::GetContext(script_contexts, |
| r.context_index); |
| } |
| } |
| |
| // Context extension objects needs to behave as if they have no |
| // prototype. So even if we want to follow prototype chains, we need |
| // to only do a local lookup for context extension objects. |
| Maybe<PropertyAttributes> maybe = Nothing<PropertyAttributes>(); |
| if ((flags & FOLLOW_PROTOTYPE_CHAIN) == 0 || |
| object->IsJSContextExtensionObject()) { |
| maybe = JSReceiver::GetOwnPropertyAttributes(object, name); |
| } else if (context->IsWithContext()) { |
| // A with context will never bind "this", but debug-eval may look into |
| // a with context when resolving "this". Other synthetic variables such |
| // as new.target may be resolved as DYNAMIC_LOCAL due to bug v8:5405 , |
| // skipping them here serves as a workaround until a more thorough |
| // fix can be applied. |
| // TODO(v8:5405): Replace this check with a DCHECK when resolution of |
| // of synthetic variables does not go through this code path. |
| if (ScopeInfo::VariableIsSynthetic(*name)) { |
| maybe = Just(ABSENT); |
| } else { |
| LookupIterator it(object, name, object); |
| Maybe<bool> found = UnscopableLookup(&it); |
| if (found.IsNothing()) { |
| maybe = Nothing<PropertyAttributes>(); |
| } else { |
| // Luckily, consumers of |maybe| only care whether the property |
| // was absent or not, so we can return a dummy |NONE| value |
| // for its attributes when it was present. |
| maybe = Just(found.FromJust() ? NONE : ABSENT); |
| } |
| } |
| } else { |
| maybe = JSReceiver::GetPropertyAttributes(object, name); |
| } |
| |
| if (maybe.IsNothing()) return Handle<Object>(); |
| DCHECK(!isolate->has_pending_exception()); |
| *attributes = maybe.FromJust(); |
| |
| if (maybe.FromJust() != ABSENT) { |
| if (FLAG_trace_contexts) { |
| PrintF("=> found property in context object %p\n", |
| reinterpret_cast<void*>(*object)); |
| } |
| return object; |
| } |
| } |
| |
| // 2. Check the context proper if it has slots. |
| if (context->IsFunctionContext() || context->IsBlockContext() || |
| context->IsScriptContext() || context->IsEvalContext() || |
| context->IsModuleContext()) { |
| // Use serialized scope information of functions and blocks to search |
| // for the context index. |
| Handle<ScopeInfo> scope_info(context->scope_info()); |
| VariableMode mode; |
| InitializationFlag flag; |
| MaybeAssignedFlag maybe_assigned_flag; |
| int slot_index = ScopeInfo::ContextSlotIndex(scope_info, name, &mode, |
| &flag, &maybe_assigned_flag); |
| DCHECK(slot_index < 0 || slot_index >= MIN_CONTEXT_SLOTS); |
| if (slot_index >= 0) { |
| if (FLAG_trace_contexts) { |
| PrintF("=> found local in context slot %d (mode = %d)\n", |
| slot_index, mode); |
| } |
| *index = slot_index; |
| *variable_mode = mode; |
| *init_flag = flag; |
| *attributes = GetAttributesForMode(mode); |
| return context; |
| } |
| |
| // Check the slot corresponding to the intermediate context holding |
| // only the function name variable. It's conceptually (and spec-wise) |
| // in an outer scope of the function's declaration scope. |
| if (follow_context_chain && (flags & STOP_AT_DECLARATION_SCOPE) == 0 && |
| context->IsFunctionContext()) { |
| int function_index = scope_info->FunctionContextSlotIndex(*name); |
| if (function_index >= 0) { |
| if (FLAG_trace_contexts) { |
| PrintF("=> found intermediate function in context slot %d\n", |
| function_index); |
| } |
| *index = function_index; |
| *attributes = READ_ONLY; |
| *init_flag = kCreatedInitialized; |
| *variable_mode = CONST; |
| if (is_sloppy_function_name != nullptr && |
| is_sloppy(scope_info->language_mode())) { |
| *is_sloppy_function_name = true; |
| } |
| return context; |
| } |
| } |
| |
| // Lookup variable in module imports and exports. |
| if (context->IsModuleContext()) { |
| VariableMode mode; |
| InitializationFlag flag; |
| MaybeAssignedFlag maybe_assigned_flag; |
| int cell_index = |
| scope_info->ModuleIndex(name, &mode, &flag, &maybe_assigned_flag); |
| if (cell_index != 0) { |
| if (FLAG_trace_contexts) { |
| PrintF("=> found in module imports or exports\n"); |
| } |
| *index = cell_index; |
| *variable_mode = mode; |
| *init_flag = flag; |
| *attributes = ModuleDescriptor::GetCellIndexKind(cell_index) == |
| ModuleDescriptor::kExport |
| ? GetAttributesForMode(mode) |
| : READ_ONLY; |
| return handle(context->module(), isolate); |
| } |
| } |
| } else if (context->IsCatchContext()) { |
| // Catch contexts have the variable name in the extension slot. |
| if (String::Equals(name, handle(context->catch_name()))) { |
| if (FLAG_trace_contexts) { |
| PrintF("=> found in catch context\n"); |
| } |
| *index = Context::THROWN_OBJECT_INDEX; |
| *attributes = NONE; |
| *init_flag = kCreatedInitialized; |
| *variable_mode = VAR; |
| return context; |
| } |
| } else if (context->IsDebugEvaluateContext()) { |
| // Check materialized locals. |
| Object* ext = context->get(EXTENSION_INDEX); |
| if (ext->IsContextExtension()) { |
| Object* obj = ContextExtension::cast(ext)->extension(); |
| if (obj->IsJSReceiver()) { |
| Handle<JSReceiver> extension(JSReceiver::cast(obj)); |
| LookupIterator it(extension, name, extension); |
| Maybe<bool> found = JSReceiver::HasProperty(&it); |
| if (found.FromMaybe(false)) { |
| *attributes = NONE; |
| return extension; |
| } |
| } |
| } |
| // Check the original context, but do not follow its context chain. |
| Object* obj = context->get(WRAPPED_CONTEXT_INDEX); |
| if (obj->IsContext()) { |
| Handle<Object> result = |
| Context::cast(obj)->Lookup(name, DONT_FOLLOW_CHAINS, index, |
| attributes, init_flag, variable_mode); |
| if (!result.is_null()) return result; |
| } |
| // Check whitelist. Names that do not pass whitelist shall only resolve |
| // to with, script or native contexts up the context chain. |
| obj = context->get(WHITE_LIST_INDEX); |
| if (obj->IsStringSet()) { |
| failed_whitelist = failed_whitelist || !StringSet::cast(obj)->Has(name); |
| } |
| } |
| |
| // 3. Prepare to continue with the previous (next outermost) context. |
| if (context->IsNativeContext() || |
| ((flags & STOP_AT_DECLARATION_SCOPE) != 0 && |
| context->is_declaration_context())) { |
| follow_context_chain = false; |
| } else { |
| do { |
| context = Handle<Context>(context->previous(), isolate); |
| // If we come across a whitelist context, and the name is not |
| // whitelisted, then only consider with, script, module or native |
| // contexts. |
| } while (failed_whitelist && !context->IsScriptContext() && |
| !context->IsNativeContext() && !context->IsWithContext() && |
| !context->IsModuleContext()); |
| } |
| } while (follow_context_chain); |
| |
| if (FLAG_trace_contexts) { |
| PrintF("=> no property/slot found\n"); |
| } |
| return Handle<Object>::null(); |
| } |
| |
| |
| void Context::AddOptimizedCode(Code* code) { |
| DCHECK(IsNativeContext()); |
| DCHECK(code->kind() == Code::OPTIMIZED_FUNCTION); |
| DCHECK(code->next_code_link()->IsUndefined(GetIsolate())); |
| code->set_next_code_link(get(OPTIMIZED_CODE_LIST)); |
| set(OPTIMIZED_CODE_LIST, code, UPDATE_WEAK_WRITE_BARRIER); |
| } |
| |
| |
| void Context::SetOptimizedCodeListHead(Object* head) { |
| DCHECK(IsNativeContext()); |
| set(OPTIMIZED_CODE_LIST, head, UPDATE_WEAK_WRITE_BARRIER); |
| } |
| |
| |
| Object* Context::OptimizedCodeListHead() { |
| DCHECK(IsNativeContext()); |
| return get(OPTIMIZED_CODE_LIST); |
| } |
| |
| |
| void Context::SetDeoptimizedCodeListHead(Object* head) { |
| DCHECK(IsNativeContext()); |
| set(DEOPTIMIZED_CODE_LIST, head, UPDATE_WEAK_WRITE_BARRIER); |
| } |
| |
| |
| Object* Context::DeoptimizedCodeListHead() { |
| DCHECK(IsNativeContext()); |
| return get(DEOPTIMIZED_CODE_LIST); |
| } |
| |
| |
| Handle<Object> Context::ErrorMessageForCodeGenerationFromStrings() { |
| Isolate* isolate = GetIsolate(); |
| Handle<Object> result(error_message_for_code_gen_from_strings(), isolate); |
| if (!result->IsUndefined(isolate)) return result; |
| return isolate->factory()->NewStringFromStaticChars( |
| "Code generation from strings disallowed for this context"); |
| } |
| |
| |
| #define COMPARE_NAME(index, type, name) \ |
| if (string->IsOneByteEqualTo(STATIC_CHAR_VECTOR(#name))) return index; |
| |
| int Context::ImportedFieldIndexForName(Handle<String> string) { |
| NATIVE_CONTEXT_IMPORTED_FIELDS(COMPARE_NAME) |
| return kNotFound; |
| } |
| |
| |
| int Context::IntrinsicIndexForName(Handle<String> string) { |
| NATIVE_CONTEXT_INTRINSIC_FUNCTIONS(COMPARE_NAME); |
| return kNotFound; |
| } |
| |
| #undef COMPARE_NAME |
| |
| #define COMPARE_NAME(index, type, name) \ |
| if (strncmp(string, #name, length) == 0) return index; |
| |
| int Context::IntrinsicIndexForName(const unsigned char* unsigned_string, |
| int length) { |
| const char* string = reinterpret_cast<const char*>(unsigned_string); |
| NATIVE_CONTEXT_INTRINSIC_FUNCTIONS(COMPARE_NAME); |
| return kNotFound; |
| } |
| |
| #undef COMPARE_NAME |
| |
| #ifdef DEBUG |
| |
| bool Context::IsBootstrappingOrNativeContext(Isolate* isolate, Object* object) { |
| // During bootstrapping we allow all objects to pass as global |
| // objects. This is necessary to fix circular dependencies. |
| return isolate->heap()->gc_state() != Heap::NOT_IN_GC || |
| isolate->bootstrapper()->IsActive() || object->IsNativeContext(); |
| } |
| |
| |
| bool Context::IsBootstrappingOrValidParentContext( |
| Object* object, Context* child) { |
| // During bootstrapping we allow all objects to pass as |
| // contexts. This is necessary to fix circular dependencies. |
| if (child->GetIsolate()->bootstrapper()->IsActive()) return true; |
| if (!object->IsContext()) return false; |
| Context* context = Context::cast(object); |
| return context->IsNativeContext() || context->IsScriptContext() || |
| context->IsModuleContext() || !child->IsModuleContext(); |
| } |
| |
| #endif |
| |
| void Context::ResetErrorsThrown() { |
| DCHECK(IsNativeContext()); |
| set_errors_thrown(Smi::FromInt(0)); |
| } |
| |
| void Context::IncrementErrorsThrown() { |
| DCHECK(IsNativeContext()); |
| |
| int previous_value = errors_thrown()->value(); |
| set_errors_thrown(Smi::FromInt(previous_value + 1)); |
| } |
| |
| |
| int Context::GetErrorsThrown() { return errors_thrown()->value(); } |
| |
| } // namespace internal |
| } // namespace v8 |
