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scopes.cc
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scopes.cc
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// Copyright 2012 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/ast/scopes.h"
#include <set>
#include "src/ast/ast.h"
#include "src/base/logging.h"
#include "src/base/optional.h"
#include "src/builtins/accessors.h"
#include "src/common/message-template.h"
#include "src/heap/local-factory-inl.h"
#include "src/logging/runtime-call-stats-scope.h"
#include "src/objects/scope-info.h"
#include "src/objects/string-inl.h"
#include "src/objects/string-set.h"
#include "src/parsing/parse-info.h"
#include "src/parsing/parser.h"
#include "src/parsing/preparse-data.h"
#include "src/zone/zone.h"
namespace v8 {
namespace internal {
// ----------------------------------------------------------------------------
// Implementation of LocalsMap
//
// Note: We are storing the handle locations as key values in the hash map.
// When inserting a new variable via Declare(), we rely on the fact that
// the handle location remains alive for the duration of that variable
// use. Because a Variable holding a handle with the same location exists
// this is ensured.
static_assert(sizeof(VariableMap) == (sizeof(void*) + 2 * sizeof(uint32_t) +
sizeof(ZoneAllocationPolicy)),
"Empty base optimization didn't kick in for VariableMap");
VariableMap::VariableMap(Zone* zone)
: ZoneHashMap(8, ZoneAllocationPolicy(zone)) {}
VariableMap::VariableMap(const VariableMap& other, Zone* zone)
: ZoneHashMap(other, ZoneAllocationPolicy(zone)) {}
Variable* VariableMap::Declare(Zone* zone, Scope* scope,
const AstRawString* name, VariableMode mode,
VariableKind kind,
InitializationFlag initialization_flag,
MaybeAssignedFlag maybe_assigned_flag,
IsStaticFlag is_static_flag, bool* was_added) {
DCHECK_EQ(zone, allocator().zone());
// AstRawStrings are unambiguous, i.e., the same string is always represented
// by the same AstRawString*.
// FIXME(marja): fix the type of Lookup.
Entry* p = ZoneHashMap::LookupOrInsert(const_cast<AstRawString*>(name),
name->Hash());
*was_added = p->value == nullptr;
if (*was_added) {
// The variable has not been declared yet -> insert it.
DCHECK_EQ(name, p->key);
Variable* variable =
zone->New<Variable>(scope, name, mode, kind, initialization_flag,
maybe_assigned_flag, is_static_flag);
p->value = variable;
}
return reinterpret_cast<Variable*>(p->value);
}
void VariableMap::Remove(Variable* var) {
const AstRawString* name = var->raw_name();
ZoneHashMap::Remove(const_cast<AstRawString*>(name), name->Hash());
}
void VariableMap::Add(Variable* var) {
const AstRawString* name = var->raw_name();
Entry* p = ZoneHashMap::LookupOrInsert(const_cast<AstRawString*>(name),
name->Hash());
DCHECK_NULL(p->value);
DCHECK_EQ(name, p->key);
p->value = var;
}
Variable* VariableMap::Lookup(const AstRawString* name) {
Entry* p = ZoneHashMap::Lookup(const_cast<AstRawString*>(name), name->Hash());
if (p != nullptr) {
DCHECK(reinterpret_cast<const AstRawString*>(p->key) == name);
DCHECK_NOT_NULL(p->value);
return reinterpret_cast<Variable*>(p->value);
}
return nullptr;
}
// ----------------------------------------------------------------------------
// Implementation of Scope
Scope::Scope(Zone* zone)
: outer_scope_(nullptr), variables_(zone), scope_type_(SCRIPT_SCOPE) {
SetDefaults();
}
Scope::Scope(Zone* zone, Scope* outer_scope, ScopeType scope_type)
: outer_scope_(outer_scope), variables_(zone), scope_type_(scope_type) {
DCHECK_NE(SCRIPT_SCOPE, scope_type);
SetDefaults();
set_language_mode(outer_scope->language_mode());
private_name_lookup_skips_outer_class_ =
outer_scope->is_class_scope() &&
outer_scope->AsClassScope()->IsParsingHeritage();
outer_scope_->AddInnerScope(this);
}
Variable* Scope::DeclareHomeObjectVariable(AstValueFactory* ast_value_factory) {
bool was_added;
Variable* home_object_variable = Declare(
zone(), ast_value_factory->dot_home_object_string(), VariableMode::kConst,
NORMAL_VARIABLE, InitializationFlag::kCreatedInitialized,
MaybeAssignedFlag::kNotAssigned, &was_added);
DCHECK(was_added);
home_object_variable->set_is_used();
home_object_variable->ForceContextAllocation();
return home_object_variable;
}
Variable* Scope::DeclareStaticHomeObjectVariable(
AstValueFactory* ast_value_factory) {
bool was_added;
Variable* static_home_object_variable =
Declare(zone(), ast_value_factory->dot_static_home_object_string(),
VariableMode::kConst, NORMAL_VARIABLE,
InitializationFlag::kCreatedInitialized,
MaybeAssignedFlag::kNotAssigned, &was_added);
DCHECK(was_added);
static_home_object_variable->set_is_used();
static_home_object_variable->ForceContextAllocation();
return static_home_object_variable;
}
DeclarationScope::DeclarationScope(Zone* zone,
AstValueFactory* ast_value_factory,
REPLMode repl_mode)
: Scope(zone),
function_kind_(repl_mode == REPLMode::kYes
? FunctionKind::kAsyncFunction
: FunctionKind::kNormalFunction),
params_(4, zone) {
DCHECK_EQ(scope_type_, SCRIPT_SCOPE);
SetDefaults();
is_repl_mode_scope_ = repl_mode == REPLMode::kYes;
receiver_ = DeclareDynamicGlobal(ast_value_factory->this_string(),
THIS_VARIABLE, this);
}
DeclarationScope::DeclarationScope(Zone* zone, Scope* outer_scope,
ScopeType scope_type,
FunctionKind function_kind)
: Scope(zone, outer_scope, scope_type),
function_kind_(function_kind),
params_(4, zone) {
DCHECK_NE(scope_type, SCRIPT_SCOPE);
SetDefaults();
}
ModuleScope::ModuleScope(DeclarationScope* script_scope,
AstValueFactory* avfactory)
: DeclarationScope(avfactory->single_parse_zone(), script_scope,
MODULE_SCOPE, FunctionKind::kModule),
module_descriptor_(
avfactory->single_parse_zone()->New<SourceTextModuleDescriptor>(
avfactory->single_parse_zone())) {
set_language_mode(LanguageMode::kStrict);
DeclareThis(avfactory);
}
ModuleScope::ModuleScope(Handle<ScopeInfo> scope_info,
AstValueFactory* avfactory)
: DeclarationScope(avfactory->single_parse_zone(), MODULE_SCOPE, avfactory,
scope_info),
module_descriptor_(nullptr) {
set_language_mode(LanguageMode::kStrict);
}
ClassScope::ClassScope(Zone* zone, Scope* outer_scope, bool is_anonymous)
: Scope(zone, outer_scope, CLASS_SCOPE),
rare_data_and_is_parsing_heritage_(nullptr),
is_anonymous_class_(is_anonymous) {
set_language_mode(LanguageMode::kStrict);
}
template <typename IsolateT>
ClassScope::ClassScope(IsolateT* isolate, Zone* zone,
AstValueFactory* ast_value_factory,
Handle<ScopeInfo> scope_info)
: Scope(zone, CLASS_SCOPE, ast_value_factory, scope_info),
rare_data_and_is_parsing_heritage_(nullptr) {
set_language_mode(LanguageMode::kStrict);
if (scope_info->ClassScopeHasPrivateBrand()) {
Variable* brand =
LookupInScopeInfo(ast_value_factory->dot_brand_string(), this);
DCHECK_NOT_NULL(brand);
EnsureRareData()->brand = brand;
}
// If the class variable is context-allocated and its index is
// saved for deserialization, deserialize it.
if (scope_info->HasSavedClassVariable()) {
String name;
int index;
std::tie(name, index) = scope_info->SavedClassVariable();
DCHECK_EQ(scope_info->ContextLocalMode(index), VariableMode::kConst);
DCHECK_EQ(scope_info->ContextLocalInitFlag(index),
InitializationFlag::kNeedsInitialization);
DCHECK_EQ(scope_info->ContextLocalMaybeAssignedFlag(index),
MaybeAssignedFlag::kMaybeAssigned);
Variable* var = DeclareClassVariable(
ast_value_factory,
ast_value_factory->GetString(name,
SharedStringAccessGuardIfNeeded(isolate)),
kNoSourcePosition);
var->AllocateTo(VariableLocation::CONTEXT,
Context::MIN_CONTEXT_SLOTS + index);
}
DCHECK(scope_info->HasPositionInfo());
set_start_position(scope_info->StartPosition());
set_end_position(scope_info->EndPosition());
}
template ClassScope::ClassScope(Isolate* isolate, Zone* zone,
AstValueFactory* ast_value_factory,
Handle<ScopeInfo> scope_info);
template ClassScope::ClassScope(LocalIsolate* isolate, Zone* zone,
AstValueFactory* ast_value_factory,
Handle<ScopeInfo> scope_info);
Scope::Scope(Zone* zone, ScopeType scope_type,
AstValueFactory* ast_value_factory, Handle<ScopeInfo> scope_info)
: outer_scope_(nullptr),
variables_(zone),
scope_info_(scope_info),
scope_type_(scope_type) {
DCHECK(!scope_info.is_null());
SetDefaults();
#ifdef DEBUG
already_resolved_ = true;
#endif
set_language_mode(scope_info->language_mode());
DCHECK_EQ(ContextHeaderLength(), num_heap_slots_);
private_name_lookup_skips_outer_class_ =
scope_info->PrivateNameLookupSkipsOuterClass();
// We don't really need to use the preparsed scope data; this is just to
// shorten the recursion in SetMustUsePreparseData.
must_use_preparsed_scope_data_ = true;
if (scope_type == BLOCK_SCOPE) {
// Set is_block_scope_for_object_literal_ based on the existence of the home
// object variable (we don't store it explicitly).
DCHECK_NOT_NULL(ast_value_factory);
int home_object_index = scope_info->ContextSlotIndex(
ast_value_factory->dot_home_object_string()->string());
DCHECK_IMPLIES(home_object_index >= 0,
scope_type == CLASS_SCOPE || scope_type == BLOCK_SCOPE);
if (home_object_index >= 0) {
is_block_scope_for_object_literal_ = true;
}
}
}
DeclarationScope::DeclarationScope(Zone* zone, ScopeType scope_type,
AstValueFactory* ast_value_factory,
Handle<ScopeInfo> scope_info)
: Scope(zone, scope_type, ast_value_factory, scope_info),
function_kind_(scope_info->function_kind()),
params_(0, zone) {
DCHECK_NE(scope_type, SCRIPT_SCOPE);
SetDefaults();
if (scope_info->SloppyEvalCanExtendVars()) {
DCHECK(!is_eval_scope());
sloppy_eval_can_extend_vars_ = true;
}
if (scope_info->ClassScopeHasPrivateBrand()) {
DCHECK(IsClassConstructor(function_kind()));
class_scope_has_private_brand_ = true;
}
}
Scope::Scope(Zone* zone, const AstRawString* catch_variable_name,
MaybeAssignedFlag maybe_assigned, Handle<ScopeInfo> scope_info)
: outer_scope_(nullptr),
variables_(zone),
scope_info_(scope_info),
scope_type_(CATCH_SCOPE) {
SetDefaults();
#ifdef DEBUG
already_resolved_ = true;
#endif
// Cache the catch variable, even though it's also available via the
// scope_info, as the parser expects that a catch scope always has the catch
// variable as first and only variable.
bool was_added;
Variable* variable =
Declare(zone, catch_variable_name, VariableMode::kVar, NORMAL_VARIABLE,
kCreatedInitialized, maybe_assigned, &was_added);
DCHECK(was_added);
AllocateHeapSlot(variable);
}
void DeclarationScope::SetDefaults() {
is_declaration_scope_ = true;
has_simple_parameters_ = true;
#if V8_ENABLE_WEBASSEMBLY
is_asm_module_ = false;
#endif // V8_ENABLE_WEBASSEMBLY
force_eager_compilation_ = false;
has_arguments_parameter_ = false;
uses_super_property_ = false;
has_checked_syntax_ = false;
has_this_reference_ = false;
has_this_declaration_ =
(is_function_scope() && !is_arrow_scope()) || is_module_scope();
needs_private_name_context_chain_recalc_ = false;
has_rest_ = false;
receiver_ = nullptr;
new_target_ = nullptr;
function_ = nullptr;
arguments_ = nullptr;
rare_data_ = nullptr;
should_eager_compile_ = false;
was_lazily_parsed_ = false;
is_skipped_function_ = false;
preparse_data_builder_ = nullptr;
class_scope_has_private_brand_ = false;
#ifdef DEBUG
DeclarationScope* outer_declaration_scope =
outer_scope_ ? outer_scope_->GetDeclarationScope() : nullptr;
is_being_lazily_parsed_ =
outer_declaration_scope ? outer_declaration_scope->is_being_lazily_parsed_
: false;
#endif
}
void Scope::SetDefaults() {
#ifdef DEBUG
scope_name_ = nullptr;
already_resolved_ = false;
needs_migration_ = false;
#endif
inner_scope_ = nullptr;
sibling_ = nullptr;
unresolved_list_.Clear();
start_position_ = kNoSourcePosition;
end_position_ = kNoSourcePosition;
calls_eval_ = false;
sloppy_eval_can_extend_vars_ = false;
scope_nonlinear_ = false;
is_hidden_ = false;
is_debug_evaluate_scope_ = false;
inner_scope_calls_eval_ = false;
force_context_allocation_for_parameters_ = false;
is_declaration_scope_ = false;
private_name_lookup_skips_outer_class_ = false;
must_use_preparsed_scope_data_ = false;
is_repl_mode_scope_ = false;
deserialized_scope_uses_external_cache_ = false;
needs_home_object_ = false;
is_block_scope_for_object_literal_ = false;
num_stack_slots_ = 0;
num_heap_slots_ = ContextHeaderLength();
set_language_mode(LanguageMode::kSloppy);
}
bool Scope::HasSimpleParameters() {
DeclarationScope* scope = GetClosureScope();
return !scope->is_function_scope() || scope->has_simple_parameters();
}
void DeclarationScope::set_should_eager_compile() {
should_eager_compile_ = !was_lazily_parsed_;
}
#if V8_ENABLE_WEBASSEMBLY
void DeclarationScope::set_is_asm_module() { is_asm_module_ = true; }
bool Scope::IsAsmModule() const {
return is_function_scope() && AsDeclarationScope()->is_asm_module();
}
bool Scope::ContainsAsmModule() const {
if (IsAsmModule()) return true;
// Check inner scopes recursively
for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
// Don't check inner functions which won't be eagerly compiled.
if (!scope->is_function_scope() ||
scope->AsDeclarationScope()->ShouldEagerCompile()) {
if (scope->ContainsAsmModule()) return true;
}
}
return false;
}
#endif // V8_ENABLE_WEBASSEMBLY
template <typename IsolateT>
Scope* Scope::DeserializeScopeChain(IsolateT* isolate, Zone* zone,
ScopeInfo scope_info,
DeclarationScope* script_scope,
AstValueFactory* ast_value_factory,
DeserializationMode deserialization_mode) {
// Reconstruct the outer scope chain from a closure's context chain.
Scope* current_scope = nullptr;
Scope* innermost_scope = nullptr;
Scope* outer_scope = nullptr;
bool cache_scope_found = false;
while (!scope_info.is_null()) {
if (scope_info.scope_type() == WITH_SCOPE) {
if (scope_info.IsDebugEvaluateScope()) {
outer_scope =
zone->New<DeclarationScope>(zone, FUNCTION_SCOPE, ast_value_factory,
handle(scope_info, isolate));
outer_scope->set_is_debug_evaluate_scope();
} else {
// For scope analysis, debug-evaluate is equivalent to a with scope.
outer_scope = zone->New<Scope>(zone, WITH_SCOPE, ast_value_factory,
handle(scope_info, isolate));
}
} else if (scope_info.scope_type() == SCRIPT_SCOPE) {
// If we reach a script scope, it's the outermost scope. Install the
// scope info of this script context onto the existing script scope to
// avoid nesting script scopes.
if (deserialization_mode == DeserializationMode::kIncludingVariables) {
script_scope->SetScriptScopeInfo(handle(scope_info, isolate));
}
if (scope_info.IsReplModeScope()) script_scope->set_is_repl_mode_scope();
DCHECK(!scope_info.HasOuterScopeInfo());
break;
} else if (scope_info.scope_type() == FUNCTION_SCOPE) {
outer_scope = zone->New<DeclarationScope>(
zone, FUNCTION_SCOPE, ast_value_factory, handle(scope_info, isolate));
#if V8_ENABLE_WEBASSEMBLY
if (scope_info.IsAsmModule()) {
outer_scope->AsDeclarationScope()->set_is_asm_module();
}
#endif // V8_ENABLE_WEBASSEMBLY
} else if (scope_info.scope_type() == EVAL_SCOPE) {
outer_scope = zone->New<DeclarationScope>(
zone, EVAL_SCOPE, ast_value_factory, handle(scope_info, isolate));
} else if (scope_info.scope_type() == CLASS_SCOPE) {
outer_scope = zone->New<ClassScope>(isolate, zone, ast_value_factory,
handle(scope_info, isolate));
} else if (scope_info.scope_type() == BLOCK_SCOPE) {
if (scope_info.is_declaration_scope()) {
outer_scope = zone->New<DeclarationScope>(
zone, BLOCK_SCOPE, ast_value_factory, handle(scope_info, isolate));
} else {
outer_scope = zone->New<Scope>(zone, BLOCK_SCOPE, ast_value_factory,
handle(scope_info, isolate));
}
} else if (scope_info.scope_type() == MODULE_SCOPE) {
outer_scope = zone->New<ModuleScope>(handle(scope_info, isolate),
ast_value_factory);
} else {
DCHECK_EQ(scope_info.scope_type(), CATCH_SCOPE);
DCHECK_EQ(scope_info.ContextLocalCount(), 1);
DCHECK_EQ(scope_info.ContextLocalMode(0), VariableMode::kVar);
DCHECK_EQ(scope_info.ContextLocalInitFlag(0), kCreatedInitialized);
DCHECK(scope_info.HasInlinedLocalNames());
String name = scope_info.ContextInlinedLocalName(0);
MaybeAssignedFlag maybe_assigned =
scope_info.ContextLocalMaybeAssignedFlag(0);
outer_scope =
zone->New<Scope>(zone,
ast_value_factory->GetString(
name, SharedStringAccessGuardIfNeeded(isolate)),
maybe_assigned, handle(scope_info, isolate));
}
if (deserialization_mode == DeserializationMode::kScopesOnly) {
outer_scope->scope_info_ = Handle<ScopeInfo>::null();
}
if (cache_scope_found) {
outer_scope->set_deserialized_scope_uses_external_cache();
} else {
DCHECK(!cache_scope_found);
cache_scope_found =
outer_scope->is_declaration_scope() && !outer_scope->is_eval_scope();
}
if (current_scope != nullptr) {
outer_scope->AddInnerScope(current_scope);
}
current_scope = outer_scope;
if (innermost_scope == nullptr) innermost_scope = current_scope;
scope_info = scope_info.HasOuterScopeInfo() ? scope_info.OuterScopeInfo()
: ScopeInfo();
}
if (deserialization_mode == DeserializationMode::kIncludingVariables) {
SetScriptScopeInfo(isolate, script_scope);
}
if (innermost_scope == nullptr) return script_scope;
script_scope->AddInnerScope(current_scope);
return innermost_scope;
}
template <typename IsolateT>
void Scope::SetScriptScopeInfo(IsolateT* isolate,
DeclarationScope* script_scope) {
if (script_scope->scope_info_.is_null()) {
script_scope->SetScriptScopeInfo(
ReadOnlyRoots(isolate).global_this_binding_scope_info_handle());
}
}
template EXPORT_TEMPLATE_DEFINE(
V8_EXPORT_PRIVATE) void Scope::SetScriptScopeInfo(Isolate* isolate,
DeclarationScope*
script_scope);
template EXPORT_TEMPLATE_DEFINE(
V8_EXPORT_PRIVATE) void Scope::SetScriptScopeInfo(LocalIsolate* isolate,
DeclarationScope*
script_scope);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
Scope* Scope::DeserializeScopeChain(
Isolate* isolate, Zone* zone, ScopeInfo scope_info,
DeclarationScope* script_scope, AstValueFactory* ast_value_factory,
DeserializationMode deserialization_mode);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE)
Scope* Scope::DeserializeScopeChain(
LocalIsolate* isolate, Zone* zone, ScopeInfo scope_info,
DeclarationScope* script_scope, AstValueFactory* ast_value_factory,
DeserializationMode deserialization_mode);
#ifdef DEBUG
bool Scope::IsReparsedMemberInitializerScope() const {
return is_declaration_scope() &&
IsClassMembersInitializerFunction(
AsDeclarationScope()->function_kind()) &&
outer_scope()->AsClassScope()->is_reparsed_class_scope();
}
#endif
DeclarationScope* Scope::AsDeclarationScope() {
DCHECK(is_declaration_scope());
return static_cast<DeclarationScope*>(this);
}
const DeclarationScope* Scope::AsDeclarationScope() const {
DCHECK(is_declaration_scope());
return static_cast<const DeclarationScope*>(this);
}
ModuleScope* Scope::AsModuleScope() {
DCHECK(is_module_scope());
return static_cast<ModuleScope*>(this);
}
const ModuleScope* Scope::AsModuleScope() const {
DCHECK(is_module_scope());
return static_cast<const ModuleScope*>(this);
}
ClassScope* Scope::AsClassScope() {
DCHECK(is_class_scope());
return static_cast<ClassScope*>(this);
}
const ClassScope* Scope::AsClassScope() const {
DCHECK(is_class_scope());
return static_cast<const ClassScope*>(this);
}
void DeclarationScope::DeclareSloppyBlockFunction(
SloppyBlockFunctionStatement* sloppy_block_function) {
sloppy_block_functions_.Add(sloppy_block_function);
}
void DeclarationScope::HoistSloppyBlockFunctions(AstNodeFactory* factory) {
DCHECK(is_sloppy(language_mode()));
DCHECK(is_function_scope() || is_eval_scope() || is_script_scope() ||
(is_block_scope() && outer_scope()->is_function_scope()));
DCHECK(HasSimpleParameters() || is_block_scope() || is_being_lazily_parsed_);
DCHECK_EQ(factory == nullptr, is_being_lazily_parsed_);
if (sloppy_block_functions_.is_empty()) return;
// In case of complex parameters the current scope is the body scope and the
// parameters are stored in the outer scope.
Scope* parameter_scope = HasSimpleParameters() ? this : outer_scope_;
DCHECK(parameter_scope->is_function_scope() || is_eval_scope() ||
is_script_scope());
DeclarationScope* decl_scope = GetNonEvalDeclarationScope();
Scope* outer_scope = decl_scope->outer_scope();
// For each variable which is used as a function declaration in a sloppy
// block,
for (SloppyBlockFunctionStatement* sloppy_block_function :
sloppy_block_functions_) {
const AstRawString* name = sloppy_block_function->name();
// If the variable wouldn't conflict with a lexical declaration
// or parameter,
// Check if there's a conflict with a parameter.
Variable* maybe_parameter = parameter_scope->LookupLocal(name);
if (maybe_parameter != nullptr && maybe_parameter->is_parameter()) {
continue;
}
// Check if there's a conflict with a lexical declaration
Scope* query_scope = sloppy_block_function->scope()->outer_scope();
bool should_hoist = true;
// It is not sufficient to just do a Lookup on query_scope: for
// example, that does not prevent hoisting of the function in
// `{ let e; try {} catch (e) { function e(){} } }`
//
// Don't use a generic cache scope, as the cache scope would be the outer
// scope and we terminate the iteration there anyway.
do {
Variable* var = query_scope->LookupInScopeOrScopeInfo(name, query_scope);
if (var != nullptr && IsLexicalVariableMode(var->mode())) {
should_hoist = false;
break;
}
query_scope = query_scope->outer_scope();
} while (query_scope != outer_scope);
if (!should_hoist) continue;
if (factory) {
DCHECK(!is_being_lazily_parsed_);
int pos = sloppy_block_function->position();
bool ok = true;
bool was_added;
auto declaration = factory->NewVariableDeclaration(pos);
// Based on the preceding checks, it doesn't matter what we pass as
// sloppy_mode_block_scope_function_redefinition.
Variable* var = DeclareVariable(
declaration, name, pos, VariableMode::kVar, NORMAL_VARIABLE,
Variable::DefaultInitializationFlag(VariableMode::kVar), &was_added,
nullptr, &ok);
DCHECK(ok);
VariableProxy* source =
factory->NewVariableProxy(sloppy_block_function->var());
VariableProxy* target = factory->NewVariableProxy(var);
Assignment* assignment = factory->NewAssignment(
sloppy_block_function->init(), target, source, pos);
assignment->set_lookup_hoisting_mode(LookupHoistingMode::kLegacySloppy);
Statement* statement = factory->NewExpressionStatement(assignment, pos);
sloppy_block_function->set_statement(statement);
} else {
DCHECK(is_being_lazily_parsed_);
bool was_added;
Variable* var = DeclareVariableName(name, VariableMode::kVar, &was_added);
if (sloppy_block_function->init() == Token::ASSIGN) {
var->SetMaybeAssigned();
}
}
}
}
bool DeclarationScope::Analyze(ParseInfo* info) {
RCS_SCOPE(info->runtime_call_stats(),
RuntimeCallCounterId::kCompileScopeAnalysis,
RuntimeCallStats::kThreadSpecific);
DCHECK_NOT_NULL(info->literal());
DeclarationScope* scope = info->literal()->scope();
base::Optional<AllowHandleDereference> allow_deref;
#ifdef DEBUG
if (scope->outer_scope() && !scope->outer_scope()->scope_info_.is_null()) {
allow_deref.emplace();
}
#endif
if (scope->is_eval_scope() && is_sloppy(scope->language_mode())) {
AstNodeFactory factory(info->ast_value_factory(), info->zone());
scope->HoistSloppyBlockFunctions(&factory);
}
// We are compiling one of four cases:
// 1) top-level code,
// 2) a function/eval/module on the top-level
// 4) a class member initializer function scope
// 3) 4 function/eval in a scope that was already resolved.
DCHECK(scope->is_script_scope() || scope->outer_scope()->is_script_scope() ||
scope->IsReparsedMemberInitializerScope() ||
scope->outer_scope()->already_resolved_);
// The outer scope is never lazy.
scope->set_should_eager_compile();
if (scope->must_use_preparsed_scope_data_) {
DCHECK_EQ(scope->scope_type_, ScopeType::FUNCTION_SCOPE);
allow_deref.emplace();
info->consumed_preparse_data()->RestoreScopeAllocationData(
scope, info->ast_value_factory(), info->zone());
}
if (!scope->AllocateVariables(info)) return false;
scope->GetScriptScope()->RewriteReplGlobalVariables();
#ifdef DEBUG
if (FLAG_print_scopes) {
PrintF("Global scope:\n");
scope->Print();
}
scope->CheckScopePositions();
scope->CheckZones();
#endif
return true;
}
void DeclarationScope::DeclareThis(AstValueFactory* ast_value_factory) {
DCHECK(has_this_declaration());
bool derived_constructor = IsDerivedConstructor(function_kind_);
receiver_ = zone()->New<Variable>(
this, ast_value_factory->this_string(),
derived_constructor ? VariableMode::kConst : VariableMode::kVar,
THIS_VARIABLE,
derived_constructor ? kNeedsInitialization : kCreatedInitialized,
kNotAssigned);
locals_.Add(receiver_);
}
void DeclarationScope::DeclareArguments(AstValueFactory* ast_value_factory) {
DCHECK(is_function_scope());
DCHECK(!is_arrow_scope());
// Because when arguments_ is not nullptr, we already declared
// "arguments exotic object" to add it into parameters before
// impl()->InsertShadowingVarBindingInitializers, so here
// only declare "arguments exotic object" when arguments_
// is nullptr
if (arguments_ != nullptr) {
return;
}
// Declare 'arguments' variable which exists in all non arrow functions. Note
// that it might never be accessed, in which case it won't be allocated during
// variable allocation.
bool was_added = false;
arguments_ =
Declare(zone(), ast_value_factory->arguments_string(), VariableMode::kVar,
NORMAL_VARIABLE, kCreatedInitialized, kNotAssigned, &was_added);
// According to ES#sec-functiondeclarationinstantiation step 18
// we should set argumentsObjectNeeded to false if has lexical
// declared arguments only when hasParameterExpressions is false
if (!was_added && IsLexicalVariableMode(arguments_->mode()) &&
has_simple_parameters_) {
// Check if there's lexically declared variable named arguments to avoid
// redeclaration. See ES#sec-functiondeclarationinstantiation, step 20.
arguments_ = nullptr;
}
}
void DeclarationScope::DeclareDefaultFunctionVariables(
AstValueFactory* ast_value_factory) {
DCHECK(is_function_scope());
DCHECK(!is_arrow_scope());
DeclareThis(ast_value_factory);
bool was_added;
new_target_ = Declare(zone(), ast_value_factory->new_target_string(),
VariableMode::kConst, NORMAL_VARIABLE,
kCreatedInitialized, kNotAssigned, &was_added);
DCHECK(was_added);
if (IsConciseMethod(function_kind_) || IsClassConstructor(function_kind_) ||
IsAccessorFunction(function_kind_)) {
EnsureRareData()->this_function = Declare(
zone(), ast_value_factory->this_function_string(), VariableMode::kConst,
NORMAL_VARIABLE, kCreatedInitialized, kNotAssigned, &was_added);
DCHECK(was_added);
}
}
Variable* DeclarationScope::DeclareFunctionVar(const AstRawString* name,
Scope* cache) {
DCHECK(is_function_scope());
DCHECK_NULL(function_);
if (cache == nullptr) cache = this;
DCHECK(this->IsOuterScopeOf(cache));
DCHECK_NULL(cache->variables_.Lookup(name));
VariableKind kind = is_sloppy(language_mode()) ? SLOPPY_FUNCTION_NAME_VARIABLE
: NORMAL_VARIABLE;
function_ = zone()->New<Variable>(this, name, VariableMode::kConst, kind,
kCreatedInitialized);
if (sloppy_eval_can_extend_vars()) {
cache->NonLocal(name, VariableMode::kDynamic);
} else {
cache->variables_.Add(function_);
}
return function_;
}
Variable* DeclarationScope::DeclareGeneratorObjectVar(
const AstRawString* name) {
DCHECK(is_function_scope() || is_module_scope() || is_repl_mode_scope());
DCHECK_NULL(generator_object_var());
Variable* result = EnsureRareData()->generator_object =
NewTemporary(name, kNotAssigned);
result->set_is_used();
return result;
}
Scope* Scope::FinalizeBlockScope() {
DCHECK(is_block_scope());
#ifdef DEBUG
DCHECK_NE(sibling_, this);
#endif
if (variables_.occupancy() > 0 ||
(is_declaration_scope() &&
AsDeclarationScope()->sloppy_eval_can_extend_vars())) {
return this;
}
DCHECK(!is_class_scope());
// Remove this scope from outer scope.
outer_scope()->RemoveInnerScope(this);
// Reparent inner scopes.
if (inner_scope_ != nullptr) {
Scope* scope = inner_scope_;
scope->outer_scope_ = outer_scope();
while (scope->sibling_ != nullptr) {
scope = scope->sibling_;
scope->outer_scope_ = outer_scope();
}
scope->sibling_ = outer_scope()->inner_scope_;
outer_scope()->inner_scope_ = inner_scope_;
inner_scope_ = nullptr;
}
// Move unresolved variables
if (!unresolved_list_.is_empty()) {
outer_scope()->unresolved_list_.Prepend(std::move(unresolved_list_));
unresolved_list_.Clear();
}
if (inner_scope_calls_eval_) outer_scope()->inner_scope_calls_eval_ = true;
// No need to propagate sloppy_eval_can_extend_vars_, since if it was relevant
// to this scope we would have had to bail out at the top.
DCHECK(!is_declaration_scope() ||
!AsDeclarationScope()->sloppy_eval_can_extend_vars());
// This block does not need a context.
num_heap_slots_ = 0;
// Mark scope as removed by making it its own sibling.
#ifdef DEBUG
sibling_ = this;
#endif
return nullptr;
}
void DeclarationScope::AddLocal(Variable* var) {
DCHECK(!already_resolved_);
// Temporaries are only placed in ClosureScopes.
DCHECK_EQ(GetClosureScope(), this);
locals_.Add(var);
}
void Scope::Snapshot::Reparent(DeclarationScope* new_parent) {
DCHECK_EQ(new_parent, outer_scope_->inner_scope_);
DCHECK_EQ(new_parent->outer_scope_, outer_scope_);
DCHECK_EQ(new_parent, new_parent->GetClosureScope());
DCHECK_NULL(new_parent->inner_scope_);
DCHECK(new_parent->unresolved_list_.is_empty());
Scope* inner_scope = new_parent->sibling_;
if (inner_scope != top_inner_scope_) {
for (; inner_scope->sibling() != top_inner_scope_;
inner_scope = inner_scope->sibling()) {
inner_scope->outer_scope_ = new_parent;
if (inner_scope->inner_scope_calls_eval_) {
new_parent->inner_scope_calls_eval_ = true;
}
DCHECK_NE(inner_scope, new_parent);
}
inner_scope->outer_scope_ = new_parent;
if (inner_scope->inner_scope_calls_eval_) {
new_parent->inner_scope_calls_eval_ = true;
}
new_parent->inner_scope_ = new_parent->sibling_;
inner_scope->sibling_ = nullptr;
// Reset the sibling rather than the inner_scope_ since we
// want to keep new_parent there.
new_parent->sibling_ = top_inner_scope_;
}
new_parent->unresolved_list_.MoveTail(&outer_scope_->unresolved_list_,
top_unresolved_);
// Move temporaries allocated for complex parameter initializers.
DeclarationScope* outer_closure = outer_scope_->GetClosureScope();
for (auto it = top_local_; it != outer_closure->locals()->end(); ++it) {
Variable* local = *it;
DCHECK_EQ(VariableMode::kTemporary, local->mode());
DCHECK_EQ(local->scope(), local->scope()->GetClosureScope());
DCHECK_NE(local->scope(), new_parent);
local->set_scope(new_parent);
}
new_parent->locals_.MoveTail(outer_closure->locals(), top_local_);
outer_closure->locals_.Rewind(top_local_);
// Move eval calls since Snapshot's creation into new_parent.
if (outer_scope_->calls_eval_) {
new_parent->RecordEvalCall();
declaration_scope_->sloppy_eval_can_extend_vars_ = false;
}
}
void Scope::ReplaceOuterScope(Scope* outer) {
DCHECK_NOT_NULL(outer);
DCHECK_NOT_NULL(outer_scope_);
DCHECK(!already_resolved_);
outer_scope_->RemoveInnerScope(this);
outer->AddInnerScope(this);
outer_scope_ = outer;
}
Variable* Scope::LookupInScopeInfo(const AstRawString* name, Scope* cache) {
DCHECK(!scope_info_.is_null());
DCHECK(this->IsOuterScopeOf(cache));
DCHECK(!cache->deserialized_scope_uses_external_cache());
// The case where where the cache can be another scope is when the cache scope
// is the last scope that doesn't use an external cache.
DCHECK_IMPLIES(
cache != this,
cache->outer_scope()->deserialized_scope_uses_external_cache());
DCHECK_NULL(cache->variables_.Lookup(name));
DisallowGarbageCollection no_gc;
String name_handle = *name->string();
ScopeInfo scope_info = *scope_info_;
// The Scope is backed up by ScopeInfo. This means it cannot operate in a
// heap-independent mode, and all strings must be internalized immediately. So
// it's ok to get the Handle<String> here.
bool found = false;
VariableLocation location;
int index;
VariableLookupResult lookup_result;
{
location = VariableLocation::CONTEXT;
index = scope_info.ContextSlotIndex(name->string(), &lookup_result);
found = index >= 0;
}
if (!found && is_module_scope()) {
location = VariableLocation::MODULE;
index = scope_info.ModuleIndex(name_handle, &lookup_result.mode,
&lookup_result.init_flag,
&lookup_result.maybe_assigned_flag);
found = index != 0;
}
if (!found) {
index = scope_info.FunctionContextSlotIndex(name_handle);
if (index < 0) return nullptr; // Nowhere found.
Variable* var = AsDeclarationScope()->DeclareFunctionVar(name, cache);
DCHECK_EQ(VariableMode::kConst, var->mode());
var->AllocateTo(VariableLocation::CONTEXT, index);
return cache->variables_.Lookup(name);
}
if (!is_module_scope()) {
DCHECK_NE(index, scope_info.ReceiverContextSlotIndex());
}
bool was_added;
Variable* var = cache->variables_.Declare(
zone(), this, name, lookup_result.mode, NORMAL_VARIABLE,
lookup_result.init_flag, lookup_result.maybe_assigned_flag,
IsStaticFlag::kNotStatic, &was_added);
DCHECK(was_added);