// 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/init/bootstrapper.h"
#include "src/logging/counters.h"
#include "src/objects/module-inl.h"
#include "src/objects/objects-inl.h"
#include "src/objects/scope-info.h"
#include "src/objects/string-set-inl.h"
#include "src/parsing/parse-info.h"
#include "src/parsing/parser.h"
#include "src/parsing/preparse-data.h"
#include "src/zone/zone-list-inl.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 ? kAsyncFunction
: 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->zone(), script_scope, MODULE_SCOPE, kModule),
module_descriptor_(avfactory->zone()->New<SourceTextModuleDescriptor>(
avfactory->zone())) {
set_language_mode(LanguageMode::kStrict);
DeclareThis(avfactory);
}
ModuleScope::ModuleScope(Isolate* isolate, Handle<ScopeInfo> scope_info,
AstValueFactory* avfactory)
: DeclarationScope(avfactory->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);
}
ClassScope::ClassScope(Isolate* 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->HasClassBrand()) {
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->HasSavedClassVariableIndex()) {
int index = scope_info->SavedClassVariableContextLocalIndex();
DCHECK_GE(index, 0);
DCHECK_LT(index, scope_info->ContextLocalCount());
String name = scope_info->ContextLocalName(index);
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(handle(name, isolate)),
kNoSourcePosition);
var->AllocateTo(VariableLocation::CONTEXT,
Context::MIN_CONTEXT_SLOTS + index);
}
}
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 existince of the home
// object variable (we don't store it explicitly).
VariableLookupResult lookup_result;
DCHECK_NOT_NULL(ast_value_factory);
int home_object_index = ScopeInfo::ContextSlotIndex(
*scope_info, *(ast_value_factory->dot_home_object_string()->string()),
&lookup_result);
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;
}
}
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;
#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
Scope* Scope::DeserializeScopeChain(Isolate* 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>(isolate, 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);
String name = scope_info.ContextLocalName(0);
MaybeAssignedFlag maybe_assigned =
scope_info.ContextLocalMaybeAssignedFlag(0);
outer_scope = zone->New<Scope>(
zone, ast_value_factory->GetString(handle(name, 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 &&
script_scope->scope_info_.is_null()) {
script_scope->SetScriptScopeInfo(
ReadOnlyRoots(isolate).global_this_binding_scope_info_handle());
}
if (innermost_scope == nullptr) return script_scope;
script_scope->AddInnerScope(current_scope);
return innermost_scope;
}
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();
Variable* var = nullptr;
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 {
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
// 3) a function/eval in a scope that was already resolved.
DCHECK(scope->is_script_scope() || scope->outer_scope()->is_script_scope() ||
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);
}
void DeclarationScope::DeclareArguments(AstValueFactory* ast_value_factory) {
DCHECK(is_function_scope());
DCHECK(!is_arrow_scope());
// 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;
arguments_ =
Declare(zone(), ast_value_factory->arguments_string(), VariableMode::kVar,
NORMAL_VARIABLE, kCreatedInitialized, kNotAssigned, &was_added);
if (!was_added && IsLexicalVariableMode(arguments_->mode())) {
// 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(!IsCleared());
DCHECK_EQ(new_parent, outer_scope_and_calls_eval_.GetPointer()->inner_scope_);
DCHECK_EQ(new_parent->outer_scope_, outer_scope_and_calls_eval_.GetPointer());
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_;
}
Scope* outer_scope_ = outer_scope_and_calls_eval_.GetPointer();
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_and_calls_eval_->calls_eval_) {
new_parent->RecordDeclarationScopeEvalCall();
new_parent->inner_scope_calls_eval_ = true;
}
// We are in the arrow function case. The calls eval we may have recorded
// is intended for the inner scope and we should simply restore the
// original "calls eval" flag of the outer scope.
RestoreEvalFlag();
Clear();
}
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 =
ScopeInfo::ContextSlotIndex(scope_info, name_handle, &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);
var->AllocateTo(location, index);
return var;
}
Variable* DeclarationScope::DeclareParameter(const AstRawString* name,
VariableMode mode,
bool is_optional, bool is_rest,
AstValueFactory* ast_value_factory,
int position) {
DCHECK(!already_resolved_);
DCHECK(is_function_scope() || is_module_scope());
DCHECK(!has_rest_);
DCHECK(!is_optional || !is_rest);
DCHECK(!is_being_lazily_parsed_);
DCHECK(!was_lazily_parsed_);
Variable* var;
if (mode == VariableMode::kTemporary) {
var = NewTemporary(name);
} else {
var = LookupLocal(name);
DCHECK_EQ(mode, VariableMode::kVar);
DCHECK(var->is_parameter());
}
has_rest_ = is_rest;
var->set_initializer_position(position);
params_.Add(var, zone());
if (!is_rest) ++num_parameters_;
if (name == ast_value_factory->arguments_string()) {
has_arguments_parameter_ = true;
}
// Params are automatically marked as used to make sure that the debugger and
// function.arguments sees them.
// TODO(verwaest): Reevaluate whether we always need to do this, since
// strict-mode function.arguments does not make the arguments available.
var->set_is_used();
return var;
}
void DeclarationScope::RecordParameter(bool is_rest) {
DCHECK(!already_resolved_);
DCHECK(is_function_scope() || is_module_scope());
DCHECK(is_being_lazily_parsed_);
DCHECK(!has_rest_);
has_rest_ = is_rest;
if (!is_rest) ++num_parameters_;
}
Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
VariableKind kind, bool* was_added,
InitializationFlag init_flag) {
DCHECK(!already_resolved_);
// Private methods should be declared with ClassScope::DeclarePrivateName()
DCHECK(!IsPrivateMethodOrAccessorVariableMode(mode));
// This function handles VariableMode::kVar, VariableMode::kLet, and
// VariableMode::kConst modes. VariableMode::kDynamic variables are
// introduced during variable allocation, and VariableMode::kTemporary
// variables are allocated via NewTemporary().
DCHECK(IsDeclaredVariableMode(mode));
DCHECK_IMPLIES(GetDeclarationScope()->is_being_lazily_parsed(),
mode == VariableMode::kVar || mode == VariableMode::kLet ||
mode == VariableMode::kConst);
DCHECK(!GetDeclarationScope()->was_lazily_parsed());
Variable* var =
Declare(zone(), name, mode, kind, init_flag, kNotAssigned, was_added);
// Pessimistically assume that top-level variables will be assigned and used.
//
// Top-level variables in a script can be accessed by other scripts or even
// become global properties. While this does not apply to top-level variables
// in a module (assuming they are not exported), we must still mark these as
// assigned because they might be accessed by a lazily parsed top-level
// function, which, for efficiency, we preparse without variable tracking.
if (is_script_scope() || is_module_scope()) {
if (mode != VariableMode::kConst) var->SetMaybeAssigned();
var->set_is_used();
}
return var;
}
Variable* Scope::DeclareVariable(
Declaration* declaration, const AstRawString* name, int pos,
VariableMode mode, VariableKind kind, InitializationFlag init,
bool* was_added, bool* sloppy_mode_block_scope_function_redefinition,
bool* ok) {
// Private methods should be declared with ClassScope::DeclarePrivateName()
DCHECK(!IsPrivateMethodOrAccessorVariableMode(mode));
DCHECK(IsDeclaredVariableMode(mode));
DCHECK(!already_resolved_);
DCHECK(!GetDeclarationScope()->is_being_lazily_parsed());
DCHECK(!GetDeclarationScope()->was_lazily_parsed());
if (mode == VariableMode::kVar && !is_declaration_scope()) {
return GetDeclarationScope()->DeclareVariable(
declaration, name, pos, mode, kind, init, was_added,
sloppy_mode_block_scope_function_redefinition, ok);
}
DCHECK(!is_catch_scope());
DCHECK(!is_with_scope());
DCHECK(is_declaration_scope() ||
(IsLexicalVariableMode(mode) && is_block_scope()));
DCHECK_NOT_NULL(name);
Variable* var = LookupLocal(name);
// Declare the variable in the declaration scope.
*was_added = var == nullptr;
if (V8_LIKELY(*was_added)) {
if (V8_UNLIKELY(is_eval_scope() && is_sloppy(language_mode()) &&
mode == VariableMode::kVar)) {
// In a var binding in a sloppy direct eval, pollute the enclosing scope
// with this new binding by doing the following:
// The proxy is bound to a lookup variable to force a dynamic declaration
// using the DeclareEvalVar or DeclareEvalFunction runtime functions.
DCHECK_EQ(NORMAL_VARIABLE, kind);
var = NonLocal(name, VariableMode::kDynamic);
// Mark the var as used in case anyone outside the eval wants to use it.
var->set_is_used();
} else {
// Declare the name.
var = DeclareLocal(name, mode, kind, was_added, init);
DCHECK(*was_added);
}
} else {
var->SetMaybeAssigned();
if (V8_UNLIKELY(IsLexicalVariableMode(mode) ||
IsLexicalVariableMode(var->mode()))) {
// The name was declared in this scope before; check for conflicting
// re-declarations. We have a conflict if either of the declarations is
// not a var (in script scope, we also have to ignore legacy const for
// compatibility). There is similar code in runtime.cc in the Declare
// functions. The function CheckConflictingVarDeclarations checks for
// var and let bindings from different scopes whereas this is a check
// for conflicting declarations within the same scope. This check also
// covers the special case
//
// function () { let x; { var x; } }
//
// because the var declaration is hoisted to the function scope where
// 'x' is already bound.
//
// In harmony we treat re-declarations as early errors. See ES5 16 for a
// definition of early errors.
//
// Allow duplicate function decls for web compat, see bug 4693.
*ok = var->is_sloppy_block_function() &&
kind == SLOPPY_BLOCK_FUNCTION_VARIABLE;
*sloppy_mode_block_scope_function_redefinition = *ok;
}
}
DCHECK_NOT_NULL(var);
// We add a declaration node for every declaration. The compiler
// will only generate code if necessary. In particular, declarations
// for inner local variables that do not represent functions won't
// result in any generated code.
//
// This will lead to multiple declaration nodes for the
// same variable if it is declared several times. This is not a
// semantic issue, but it may be a performance issue since it may
// lead to repeated DeclareEvalVar or DeclareEvalFunction calls.
decls_.Add(declaration);
declaration->set_var(var);
return var;
}
Variable* Scope::DeclareVariableName(const AstRawString* name,
VariableMode mode, bool* was_added,
VariableKind kind) {
DCHECK(IsDeclaredVariableMode(mode));
DCHECK(!already_resolved_);
DCHECK(GetDeclarationScope()->is_being_lazily_parsed());
// Private methods should be declared with ClassScope::DeclarePrivateName()
DCHECK(!IsPrivateMethodOrAccessorVariableMode(mode));
if (mode == VariableMode::kVar && !is_declaration_scope()) {
return GetDeclarationScope()->DeclareVariableName(name, mode, was_added,
kind);
}
DCHECK(!is_with_scope());
DCHECK(!is_eval_scope());
DCHECK(is_declaration_scope() || IsLexicalVariableMode(mode));
DCHECK(scope_info_.is_null());
// Declare the variable in the declaration scope.
Variable* var = DeclareLocal(name, mode, kind, was_added);
if (!*was_added) {
if (IsLexicalVariableMode(mode) || IsLexicalVariableMode(var->mode())) {
if (!var->is_sloppy_block_function() ||
kind != SLOPPY_BLOCK_FUNCTION_VARIABLE) {
// Duplicate functions are allowed in the sloppy mode, but if this is
// not a function declaration, it's an error. This is an error PreParser
// hasn't previously detected.
return nullptr;
}
// Sloppy block function redefinition.
}
var->SetMaybeAssigned();
}
var->set_is_used();
return var;
}
Variable* Scope::DeclareCatchVariableName(const AstRawString* name) {
DCHECK(!already_resolved_);
DCHECK(is_catch_scope());
DCHECK(scope_info_.is_null());
bool was_added;
Variable* result = Declare(zone(), name, VariableMode::kVar, NORMAL_VARIABLE,
kCreatedInitialized, kNotAssigned, &was_added);
DCHECK(was_added);
return result;
}
void Scope::AddUnresolved(VariableProxy* proxy) {
DCHECK(!already_resolved_);
DCHECK(!proxy->is_resolved());
unresolved_list_.Add(proxy);
}
Variable* DeclarationScope::DeclareDynamicGlobal(const AstRawString* name,
VariableKind kind,
Scope* cache) {
DCHECK(is_script_scope());
bool was_added;
return cache->variables_.Declare(
zone(), this, name, VariableMode::kDynamicGlobal, kind,
kCreatedInitialized, kNotAssigned, IsStaticFlag::kNotStatic, &was_added);
// TODO(neis): Mark variable as maybe-assigned?
}
bool Scope::RemoveUnresolved(VariableProxy* var) {
return unresolved_list_.Remove(var);
}
void Scope::DeleteUnresolved(VariableProxy* var) {
DCHECK(unresolved_list_.Contains(var));
var->mark_removed_from_unresolved();
}
Variable* Scope::NewTemporary(const AstRawString* name) {
return NewTemporary(name, kMaybeAssigned);
}
Variable* Scope::NewTemporary(const AstRawString* name,
MaybeAssignedFlag maybe_assigned) {
DeclarationScope* scope = GetClosureScope();
Variable* var = zone()->New<Variable>(scope, name, VariableMode::kTemporary,
NORMAL_VARIABLE, kCreatedInitialized);
scope->AddLocal(var);
if (maybe_assigned == kMaybeAssigned) var->SetMaybeAssigned();
return var;
}
Declaration* DeclarationScope::CheckConflictingVarDeclarations(
bool* allowed_catch_binding_var_redeclaration) {
if (has_checked_syntax_) return nullptr;
for (Declaration* decl : decls_) {
// Lexical vs lexical conflicts within the same scope have already been
// captured in Parser::Declare. The only conflicts we still need to check
// are lexical vs nested var.
if (decl->IsVariableDeclaration() &&
decl->AsVariableDeclaration()->AsNested() != nullptr) {
Scope* current = decl->AsVariableDeclaration()->AsNested()->scope();
DCHECK(decl->var()->mode() == VariableMode::kVar ||
decl->var()->mode() == VariableMode::kDynamic);
// Iterate through all scopes until the declaration scope.
do {
// There is a conflict if there exists a non-VAR binding.
Variable* other_var = current->LookupLocal(decl->var()->raw_name());
if (current->is_catch_scope()) {
*allowed_catch_binding_var_redeclaration |= other_var != nullptr;
current = current->outer_scope();
continue;
}
if (other_var != nullptr) {
DCHECK(IsLexicalVariableMode(other_var->mode()));
return decl;
}
current = current->outer_scope();
} while (current != this);
}
}
if (V8_LIKELY(!is_eval_scope())) return nullptr;
if (!is_sloppy(language_mode())) return nullptr;
// Var declarations in sloppy eval are hoisted to the first non-eval
// declaration scope. Check for conflicts between the eval scope that
// declaration scope.
Scope* end = outer_scope()->GetNonEvalDeclarationScope()->outer_scope();
for (Declaration* decl : decls_) {
if (IsLexicalVariableMode(decl->var()->mode())) continue;
Scope* current = outer_scope_;
// Iterate through all scopes until and including the declaration scope.
do {
// There is a conflict if there exists a non-VAR binding up to the
// declaration scope in which this sloppy-eval runs.
//
// Use the current scope as the cache, since the general cache would be
// the end scope.
Variable* other_var =
current->LookupInScopeOrScopeInfo(decl->var()->raw_name(), current);
if (other_var != nullptr && !current->is_catch_scope()) {
// If this is a VAR, then we know that it doesn't conflict with
// anything, so we can't conflict with anything either. The one
// exception is the binding variable in catch scopes, which is handled
// by the if above.
if (!IsLexicalVariableMode(other_var->mode())) break;
return decl;
}
current = current->outer_scope();
} while (current != end);
}
return nullptr;
}
const AstRawString* Scope::FindVariableDeclaredIn(Scope* scope,
VariableMode mode_limit) {
const VariableMap& variables = scope->variables_;
for (ZoneHashMap::Entry* p = variables.Start(); p != nullptr;
p = variables.Next(p)) {
const AstRawString* name = static_cast<const AstRawString*>(p->key);
Variable* var = LookupLocal(name);
if (var != nullptr && var->mode() <= mode_limit) return name;
}
return nullptr;
}
void DeclarationScope::DeserializeReceiver(AstValueFactory* ast_value_factory) {
if (is_script_scope()) {
DCHECK_NOT_NULL(receiver_);
return;
}
DCHECK(has_this_declaration());
DeclareThis(ast_value_factory);
if (is_debug_evaluate_scope()) {
receiver_->AllocateTo(VariableLocation::LOOKUP, -1);
} else {
receiver_->AllocateTo(VariableLocation::CONTEXT,
scope_info_->ReceiverContextSlotIndex());
}
}
bool DeclarationScope::AllocateVariables(ParseInfo* info) {
// Module variables must be allocated before variable resolution
// to ensure that UpdateNeedsHoleCheck() can detect import variables.
if (is_module_scope()) AsModuleScope()->AllocateModuleVariables();
PrivateNameScopeIterator private_name_scope_iter(this);
if (!private_name_scope_iter.Done() &&
!private_name_scope_iter.GetScope()->ResolvePrivateNames(info)) {
DCHECK(info->pending_error_handler()->has_pending_error());
return false;
}
if (!ResolveVariablesRecursively(info->scope())) {
DCHECK(info->pending_error_handler()->has_pending_error());
return false;
}
// Don't allocate variables of preparsed scopes.
if (!was_lazily_parsed()) AllocateVariablesRecursively();
return true;
}
bool Scope::HasThisReference() const {
if (is_declaration_scope() && AsDeclarationScope()->has_this_reference()) {
return true;
}
for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
if (!scope->is_declaration_scope() ||
!scope->AsDeclarationScope()->has_this_declaration()) {
if (scope->HasThisReference()) return true;
}
}
return false;
}
bool Scope::AllowsLazyParsingWithoutUnresolvedVariables(
const Scope* outer) const {
// If none of the outer scopes need to decide whether to context allocate
// specific variables, we can preparse inner functions without unresolved
// variables. Otherwise we need to find unresolved variables to force context
// allocation of the matching declarations. We can stop at the outer scope for
// the parse, since context allocation of those variables is already
// guaranteed to be correct.
for (const Scope* s = this; s != outer; s = s->outer_scope_) {
// Eval forces context allocation on all outer scopes, so we don't need to
// look at those scopes. Sloppy eval makes top-level non-lexical variables
// dynamic, whereas strict-mode requires context allocation.
if (s->is_eval_scope()) return is_sloppy(s->language_mode());
// Catch scopes force context allocation of all variables.
if (s->is_catch_scope()) continue;
// With scopes do not introduce variables that need allocation.
if (s->is_with_scope()) continue;
DCHECK(s->is_module_scope() || s->is_block_scope() ||
s->is_function_scope());
return false;
}
return true;
}
bool DeclarationScope::AllowsLazyCompilation() const {
// Functions which force eager compilation and class member initializer
// functions are not lazily compilable.
return !force_eager_compilation_ &&
!IsClassMembersInitializerFunction(function_kind());
}
int Scope::ContextChainLength(Scope* scope) const {
int n = 0;
for (const Scope* s = this; s != scope; s = s->outer_scope_) {
DCHECK_NOT_NULL(s); // scope must be in the scope chain
if (s->NeedsContext()) n++;
}
return n;
}
int Scope::ContextChainLengthUntilOutermostSloppyEval() const {
int result = 0;
int length = 0;
for (const Scope* s = this; s != nullptr; s = s->outer_scope()) {
if (!s->NeedsContext()) continue;
length++;
if (s->is_declaration_scope() &&
s->AsDeclarationScope()->sloppy_eval_can_extend_vars()) {
result = length;
}
}
return result;
}
DeclarationScope* Scope::GetDeclarationScope() {
Scope* scope = this;
while (!scope->is_declaration_scope()) {
scope = scope->outer_scope();
}
return scope->AsDeclarationScope();
}
DeclarationScope* Scope::GetNonEvalDeclarationScope() {
Scope* scope = this;
while (!scope->is_declaration_scope() || scope->is_eval_scope()) {
scope = scope->outer_scope();
}
return scope->AsDeclarationScope();
}
const DeclarationScope* Scope::GetClosureScope() const {
const Scope* scope = this;
while (!scope->is_declaration_scope() || scope->is_block_scope()) {
scope = scope->outer_scope();
}
return scope->AsDeclarationScope();
}
DeclarationScope* Scope::GetClosureScope() {
Scope* scope = this;
while (!scope->is_declaration_scope() || scope->is_block_scope()) {
scope = scope->outer_scope();
}
return scope->AsDeclarationScope();
}
bool Scope::NeedsScopeInfo() const {
DCHECK(!already_resolved_);
DCHECK(GetClosureScope()->ShouldEagerCompile());
// The debugger expects all functions to have scope infos.
// TODO(jochen|yangguo): Remove this requirement.
if (is_function_scope()) return true;
return NeedsContext();
}
bool Scope::ShouldBanArguments() {
return GetReceiverScope()->should_ban_arguments();
}
DeclarationScope* Scope::GetReceiverScope() {
Scope* scope = this;
while (!scope->is_declaration_scope() ||
(!scope->is_script_scope() &&
!scope->AsDeclarationScope()->has_this_declaration())) {
scope = scope->outer_scope();
}
return scope->AsDeclarationScope();
}
Scope* Scope::GetHomeObjectScope() {
Scope* scope = this;
while (scope != nullptr && !scope->is_home_object_scope()) {
if (scope->is_function_scope()) {
FunctionKind function_kind = scope->AsDeclarationScope()->function_kind();
// "super" in arrow functions binds outside the arrow function. But if we
// find a function which doesn't bind "super" (is not a method etc.) and
// not an arrow function, we know "super" here doesn't bind anywhere and
// we can return nullptr.
if (!IsArrowFunction(function_kind) && !BindsSuper(function_kind)) {
return nullptr;
}
}
if (scope->private_name_lookup_skips_outer_class()) {
DCHECK(scope->outer_scope()->is_class_scope());
scope = scope->outer_scope()->outer_scope();
} else {
scope = scope->outer_scope();
}
}
return scope;
}
DeclarationScope* Scope::GetScriptScope() {
Scope* scope = this;
while (!scope->is_script_scope()) {
scope = scope->outer_scope();
}
return scope->AsDeclarationScope();
}
Scope* Scope::GetOuterScopeWithContext() {
Scope* scope = outer_scope_;
while (scope && !scope->NeedsContext()) {
scope = scope->outer_scope();
}
return scope;
}
namespace {
bool WasLazilyParsed(Scope* scope) {
return scope->is_declaration_scope() &&
scope->AsDeclarationScope()->was_lazily_parsed();
}
} // namespace
template <typename FunctionType>
void Scope::ForEach(FunctionType callback) {
Scope* scope = this;
while (true) {
Iteration iteration = callback(scope);
// Try to descend into inner scopes first.
if ((iteration == Iteration::kDescend) && scope->inner_scope_ != nullptr) {
scope = scope->inner_scope_;
} else {
// Find the next outer scope with a sibling.
while (scope->sibling_ == nullptr) {
if (scope == this) return;
scope = scope->outer_scope_;
}
if (scope == this) return;
scope = scope->sibling_;
}
}
}
bool Scope::IsOuterScopeOf(Scope* other) const {
Scope* scope = other;
while (scope) {
if (scope == this) return true;
scope = scope->outer_scope();
}
return false;
}
void Scope::CollectNonLocals(DeclarationScope* max_outer_scope,
Isolate* isolate, Handle<StringSet>* non_locals) {
this->ForEach([max_outer_scope, isolate, non_locals](Scope* scope) {
// Module variables must be allocated before variable resolution
// to ensure that UpdateNeedsHoleCheck() can detect import variables.
if (scope->is_module_scope()) {
scope->AsModuleScope()->AllocateModuleVariables();
}
// Lazy parsed declaration scopes are already partially analyzed. If there
// are unresolved references remaining, they just need to be resolved in
// outer scopes.
Scope* lookup = WasLazilyParsed(scope) ? scope->outer_scope() : scope;
for (VariableProxy* proxy : scope->unresolved_list_) {
DCHECK(!proxy->is_resolved());
Variable* var =
Lookup<kParsedScope>(proxy, lookup, max_outer_scope->outer_scope());
if (var == nullptr) {
*non_locals = StringSet::Add(isolate, *non_locals, proxy->name());
} else {
// In this case we need to leave scopes in a way that they can be
// allocated. If we resolved variables from lazy parsed scopes, we need
// to context allocate the var.
scope->ResolveTo(proxy, var);
if (!var->is_dynamic() && lookup != scope)
var->ForceContextAllocation();
}
}
// Clear unresolved_list_ as it's in an inconsistent state.
scope->unresolved_list_.Clear();
return Iteration::kDescend;
});
}
void Scope::AnalyzePartially(DeclarationScope* max_outer_scope,
AstNodeFactory* ast_node_factory,
UnresolvedList* new_unresolved_list,
bool maybe_in_arrowhead) {
this->ForEach([max_outer_scope, ast_node_factory, new_unresolved_list,
maybe_in_arrowhead](Scope* scope) {
DCHECK_IMPLIES(scope->is_declaration_scope(),
!scope->AsDeclarationScope()->was_lazily_parsed());
for (VariableProxy* proxy = scope->unresolved_list_.first();
proxy != nullptr; proxy = proxy->next_unresolved()) {
if (proxy->is_removed_from_unresolved()) continue;
DCHECK(!proxy->is_resolved());
Variable* var =
Lookup<kParsedScope>(proxy, scope, max_outer_scope->outer_scope());
if (var == nullptr) {
// Don't copy unresolved references to the script scope, unless it's a
// reference to a private name or method. In that case keep it so we
// can fail later.
if (!max_outer_scope->outer_scope()->is_script_scope() ||
maybe_in_arrowhead) {
VariableProxy* copy = ast_node_factory->CopyVariableProxy(proxy);
new_unresolved_list->Add(copy);
}
} else {
var->set_is_used();
if (proxy->is_assigned()) var->SetMaybeAssigned();
}
}
// Clear unresolved_list_ as it's in an inconsistent state.
scope->unresolved_list_.Clear();
return Iteration::kDescend;
});
}
Handle<StringSet> DeclarationScope::CollectNonLocals(
Isolate* isolate, Handle<StringSet> non_locals) {
Scope::CollectNonLocals(this, isolate, &non_locals);
return non_locals;
}
void DeclarationScope::ResetAfterPreparsing(AstValueFactory* ast_value_factory,
bool aborted) {
DCHECK(is_function_scope());
// Reset all non-trivial members.
params_.DropAndClear();
decls_.Clear();
locals_.Clear();
inner_scope_ = nullptr;
unresolved_list_.Clear();
sloppy_block_functions_.Clear();
rare_data_ = nullptr;
has_rest_ = false;
function_ = nullptr;
DCHECK_NE(zone(), ast_value_factory->zone());
// Make sure this scope and zone aren't used for allocation anymore.
{
// Get the zone, while variables_ is still valid
Zone* zone = this->zone();
variables_.Invalidate();
zone->ReleaseMemory();
}
if (aborted) {
// Prepare scope for use in the outer zone.
variables_ = VariableMap(ast_value_factory->zone());
if (!IsArrowFunction(function_kind_)) {
has_simple_parameters_ = true;
DeclareDefaultFunctionVariables(ast_value_factory);
}
}
#ifdef DEBUG
needs_migration_ = false;
is_being_lazily_parsed_ = false;
#endif
was_lazily_parsed_ = !aborted;
}
bool Scope::IsSkippableFunctionScope() {
// Lazy non-arrow function scopes are skippable. Lazy functions are exactly
// those Scopes which have their own PreparseDataBuilder object. This
// logic ensures that the scope allocation data is consistent with the
// skippable function data (both agree on where the lazy function boundaries
// are).
if (!is_function_scope()) return false;
DeclarationScope* declaration_scope = AsDeclarationScope();
return !declaration_scope->is_arrow_scope() &&
declaration_scope->preparse_data_builder() != nullptr;
}
void Scope::SavePreparseData(Parser* parser) {
this->ForEach([parser](Scope* scope) {
if (scope->IsSkippableFunctionScope()) {
scope->AsDeclarationScope()->SavePreparseDataForDeclarationScope(parser);
}
return Iteration::kDescend;
});
}
void DeclarationScope::SavePreparseDataForDeclarationScope(Parser* parser) {
if (preparse_data_builder_ == nullptr) return;
preparse_data_builder_->SaveScopeAllocationData(this, parser);
}
void DeclarationScope::AnalyzePartially(Parser* parser,
AstNodeFactory* ast_node_factory,
bool maybe_in_arrowhead) {
DCHECK(!force_eager_compilation_);
UnresolvedList new_unresolved_list;
if (!IsArrowFunction(function_kind_) &&
(!outer_scope_->is_script_scope() || maybe_in_arrowhead ||
(preparse_data_builder_ != nullptr &&
preparse_data_builder_->HasInnerFunctions()))) {
// Try to resolve unresolved variables for this Scope and migrate those
// which cannot be resolved inside. It doesn't make sense to try to resolve
// them in the outer Scopes here, because they are incomplete.
Scope::AnalyzePartially(this, ast_node_factory, &new_unresolved_list,
maybe_in_arrowhead);
// Migrate function_ to the right Zone.
if (function_ != nullptr) {
function_ = ast_node_factory->CopyVariable(function_);
}
SavePreparseData(parser);
}
#ifdef DEBUG
if (FLAG_print_scopes) {
PrintF("Inner function scope:\n");
Print();
}
#endif
ResetAfterPreparsing(ast_node_factory->ast_value_factory(), false);
unresolved_list_ = std::move(new_unresolved_list);
}
void DeclarationScope::RewriteReplGlobalVariables() {
DCHECK(is_script_scope());
if (!is_repl_mode_scope()) return;
for (VariableMap::Entry* p = variables_.Start(); p != nullptr;
p = variables_.Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
var->RewriteLocationForRepl();
}
}
#ifdef DEBUG
namespace {
const char* Header(ScopeType scope_type, FunctionKind function_kind,
bool is_declaration_scope) {
switch (scope_type) {
case EVAL_SCOPE: return "eval";
case FUNCTION_SCOPE:
if (IsGeneratorFunction(function_kind)) return "function*";
if (IsAsyncFunction(function_kind)) return "async function";
if (IsArrowFunction(function_kind)) return "arrow";
return "function";
case MODULE_SCOPE: return "module";
case SCRIPT_SCOPE: return "global";
case CATCH_SCOPE: return "catch";
case BLOCK_SCOPE: return is_declaration_scope ? "varblock" : "block";
case CLASS_SCOPE:
return "class";
case WITH_SCOPE: return "with";
}
UNREACHABLE();
}
void Indent(int n, const char* str) { PrintF("%*s%s", n, "", str); }
void PrintName(const AstRawString* name) {
PrintF("%.*s", name->length(), name->raw_data());
}
void PrintLocation(Variable* var) {
switch (var->location()) {
case VariableLocation::UNALLOCATED:
break;
case VariableLocation::PARAMETER:
PrintF("parameter[%d]", var->index());
break;
case VariableLocation::LOCAL:
PrintF("local[%d]", var->index());
break;
case VariableLocation::CONTEXT:
PrintF("context[%d]", var->index());
break;
case VariableLocation::LOOKUP:
PrintF("lookup");
break;
case VariableLocation::MODULE:
PrintF("module");
break;
case VariableLocation::REPL_GLOBAL:
PrintF("repl global[%d]", var->index());
break;
}
}
void PrintVar(int indent, Variable* var) {
Indent(indent, VariableMode2String(var->mode()));
PrintF(" ");
if (var->raw_name()->IsEmpty())
PrintF(".%p", reinterpret_cast<void*>(var));
else
PrintName(var->raw_name());
PrintF("; // (%p) ", reinterpret_cast<void*>(var));
PrintLocation(var);
bool comma = !var->IsUnallocated();
if (var->has_forced_context_allocation()) {
if (comma) PrintF(", ");
PrintF("forced context allocation");
comma = true;
}
if (var->maybe_assigned() == kNotAssigned) {
if (comma) PrintF(", ");
PrintF("never assigned");
comma = true;
}
if (var->initialization_flag() == kNeedsInitialization &&
!var->binding_needs_init()) {
if (comma) PrintF(", ");
PrintF("hole initialization elided");
}
PrintF("\n");
}
void PrintMap(int indent, const char* label, VariableMap* map, bool locals,
Variable* function_var) {
bool printed_label = false;
for (VariableMap::Entry* p = map->Start(); p != nullptr; p = map->Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
if (var == function_var) continue;
bool local = !IsDynamicVariableMode(var->mode());
if ((locals ? local : !local) &&
(var->is_used() || !var->IsUnallocated())) {
if (!printed_label) {
Indent(indent, label);
printed_label = true;
}
PrintVar(indent, var);
}
}
}
} // anonymous namespace
void DeclarationScope::PrintParameters() {
PrintF(" (");
for (int i = 0; i < params_.length(); i++) {
if (i > 0) PrintF(", ");
const AstRawString* name = params_[i]->raw_name();
if (name->IsEmpty()) {
PrintF(".%p", reinterpret_cast<void*>(params_[i]));
} else {
PrintName(name);
}
}
PrintF(")");
}
void Scope::Print(int n) {
int n0 = (n > 0 ? n : 0);
int n1 = n0 + 2; // indentation
// Print header.
FunctionKind function_kind = is_function_scope()
? AsDeclarationScope()->function_kind()
: kNormalFunction;
Indent(n0, Header(scope_type_, function_kind, is_declaration_scope()));
if (scope_name_ != nullptr && !scope_name_->IsEmpty()) {
PrintF(" ");
PrintName(scope_name_);
}
// Print parameters, if any.
Variable* function = nullptr;
if (is_function_scope()) {
AsDeclarationScope()->PrintParameters();
function = AsDeclarationScope()->function_var();
}
PrintF(" { // (%p) (%d, %d)\n", reinterpret_cast<void*>(this),
start_position(), end_position());
if (is_hidden()) {
Indent(n1, "// is hidden\n");
}
// Function name, if any (named function literals, only).
if (function != nullptr) {
Indent(n1, "// (local) function name: ");
PrintName(function->raw_name());
PrintF("\n");
}
// Scope info.
if (is_strict(language_mode())) {
Indent(n1, "// strict mode scope\n");
}
#if V8_ENABLE_WEBASSEMBLY
if (IsAsmModule()) Indent(n1, "// scope is an asm module\n");
#endif // V8_ENABLE_WEBASSEMBLY
if (is_declaration_scope() &&
AsDeclarationScope()->sloppy_eval_can_extend_vars()) {
Indent(n1, "// scope calls sloppy 'eval'\n");
}
if (private_name_lookup_skips_outer_class()) {
Indent(n1, "// scope skips outer class for #-names\n");
}
if (inner_scope_calls_eval_) Indent(n1, "// inner scope calls 'eval'\n");
if (is_declaration_scope()) {
DeclarationScope* scope = AsDeclarationScope();
if (scope->was_lazily_parsed()) Indent(n1, "// lazily parsed\n");
if (scope->ShouldEagerCompile()) Indent(n1, "// will be compiled\n");
if (scope->needs_private_name_context_chain_recalc()) {
Indent(n1, "// needs #-name context chain recalc\n");
}
}
if (num_stack_slots_ > 0) {
Indent(n1, "// ");
PrintF("%d stack slots\n", num_stack_slots_);
}
if (num_heap_slots_ > 0) {
Indent(n1, "// ");
PrintF("%d heap slots\n", num_heap_slots_);
}
// Print locals.
if (function != nullptr) {
Indent(n1, "// function var:\n");
PrintVar(n1, function);
}
// Print temporaries.
{
bool printed_header = false;
for (Variable* local : locals_) {
if (local->mode() != VariableMode::kTemporary) continue;
if (!printed_header) {
printed_header = true;
Indent(n1, "// temporary vars:\n");
}
PrintVar(n1, local);
}
}
if (variables_.occupancy() > 0) {
PrintMap(n1, "// local vars:\n", &variables_, true, function);
PrintMap(n1, "// dynamic vars:\n", &variables_, false, function);
}
if (is_class_scope()) {
ClassScope* class_scope = AsClassScope();
if (class_scope->GetRareData() != nullptr) {
PrintMap(n1, "// private name vars:\n",
&(class_scope->GetRareData()->private_name_map), true, function);
Variable* brand = class_scope->brand();
if (brand != nullptr) {
Indent(n1, "// brand var:\n");
PrintVar(n1, brand);
}
}
if (class_scope->class_variable() != nullptr) {
Indent(n1, "// class var");
PrintF("%s%s:\n",
class_scope->class_variable()->is_used() ? ", used" : ", unused",
class_scope->should_save_class_variable_index()
? ", index saved"
: ", index not saved");
PrintVar(n1, class_scope->class_variable());
}
}
// Print inner scopes (disable by providing negative n).
if (n >= 0) {
for (Scope* scope = inner_scope_; scope != nullptr;
scope = scope->sibling_) {
PrintF("\n");
scope->Print(n1);
}
}
Indent(n0, "}\n");
}
void Scope::CheckScopePositions() {
this->ForEach([](Scope* scope) {
// Visible leaf scopes must have real positions.
if (!scope->is_hidden() && scope->inner_scope_ == nullptr) {
DCHECK_NE(kNoSourcePosition, scope->start_position());
DCHECK_NE(kNoSourcePosition, scope->end_position());
}
return Iteration::kDescend;
});
}
void Scope::CheckZones() {
DCHECK(!needs_migration_);
this->ForEach([](Scope* scope) {
if (WasLazilyParsed(scope)) {
DCHECK_NULL(scope->zone());
DCHECK_NULL(scope->inner_scope_);
return Iteration::kContinue;
}
return Iteration::kDescend;
});
}
#endif // DEBUG
Variable* Scope::NonLocal(const AstRawString* name, VariableMode mode) {
// Declare a new non-local.
DCHECK(IsDynamicVariableMode(mode));
bool was_added;
Variable* var = variables_.Declare(zone(), this, name, mode, NORMAL_VARIABLE,
kCreatedInitialized, kNotAssigned,
IsStaticFlag::kNotStatic, &was_added);
// Allocate it by giving it a dynamic lookup.
var->AllocateTo(VariableLocation::LOOKUP, -1);
return var;
}
// static
template <Scope::ScopeLookupMode mode>
Variable* Scope::Lookup(VariableProxy* proxy, Scope* scope,
Scope* outer_scope_end, Scope* cache_scope,
bool force_context_allocation) {
// If we have already passed the cache scope in earlier recursions, we should
// first quickly check if the current scope uses the cache scope before
// continuing.
if (mode == kDeserializedScope &&
scope->deserialized_scope_uses_external_cache()) {
Variable* var = cache_scope->variables_.Lookup(proxy->raw_name());
if (var != nullptr) return var;
}
while (true) {
DCHECK_IMPLIES(mode == kParsedScope, !scope->is_debug_evaluate_scope_);
// Short-cut: whenever we find a debug-evaluate scope, just look everything
// up dynamically. Debug-evaluate doesn't properly create scope info for the
// lookups it does. It may not have a valid 'this' declaration, and anything
// accessed through debug-evaluate might invalidly resolve to
// stack-allocated variables.
// TODO(yangguo): Remove once debug-evaluate creates proper ScopeInfo for
// the scopes in which it's evaluating.
if (mode == kDeserializedScope &&
V8_UNLIKELY(scope->is_debug_evaluate_scope_)) {
DCHECK(scope->deserialized_scope_uses_external_cache() ||
scope == cache_scope);
return cache_scope->NonLocal(proxy->raw_name(), VariableMode::kDynamic);
}
// Try to find the variable in this scope.
Variable* var;
if (mode == kParsedScope) {
var = scope->LookupLocal(proxy->raw_name());
} else {
DCHECK_EQ(mode, kDeserializedScope);
bool external_cache = scope->deserialized_scope_uses_external_cache();
if (!external_cache) {
// Check the cache on each deserialized scope, up to the main cache
// scope when we get to it (we may still have deserialized scopes
// in-between the initial and cache scopes so we can't just check the
// cache before the loop).
Variable* var = scope->variables_.Lookup(proxy->raw_name());
if (var != nullptr) return var;
}
var = scope->LookupInScopeInfo(proxy->raw_name(),
external_cache ? cache_scope : scope);
}
// We found a variable and we are done. (Even if there is an 'eval' in this
// scope which introduces the same variable again, the resulting variable
// remains the same.)
//
// For sloppy eval though, we skip dynamic variable to avoid resolving to a
// variable when the variable and proxy are in the same eval execution. The
// variable is not available on subsequent lazy executions of functions in
// the eval, so this avoids inner functions from looking up different
// variables during eager and lazy compilation.
//
// TODO(leszeks): Maybe we want to restrict this to e.g. lookups of a proxy
// living in a different scope to the current one, or some other
// optimisation.
if (var != nullptr &&
!(scope->is_eval_scope() && var->mode() == VariableMode::kDynamic)) {
if (mode == kParsedScope && force_context_allocation &&
!var->is_dynamic()) {
var->ForceContextAllocation();
}
return var;
}
if (scope->outer_scope_ == outer_scope_end) break;
DCHECK(!scope->is_script_scope());
if (V8_UNLIKELY(scope->is_with_scope())) {
return LookupWith(proxy, scope, outer_scope_end, cache_scope,
force_context_allocation);
}
if (V8_UNLIKELY(
scope->is_declaration_scope() &&
scope->AsDeclarationScope()->sloppy_eval_can_extend_vars())) {
return LookupSloppyEval(proxy, scope, outer_scope_end, cache_scope,
force_context_allocation);
}
force_context_allocation |= scope->is_function_scope();
scope = scope->outer_scope_;
// TODO(verwaest): Separate through AnalyzePartially.
if (mode == kParsedScope && !scope->scope_info_.is_null()) {
DCHECK_NULL(cache_scope);
Scope* cache_scope = scope->GetNonEvalDeclarationScope();
return Lookup<kDeserializedScope>(proxy, scope, outer_scope_end,
cache_scope);
}
}
// We may just be trying to find all free variables. In that case, don't
// declare them in the outer scope.
// TODO(marja): Separate Lookup for preparsed scopes better.
if (mode == kParsedScope && !scope->is_script_scope()) {
return nullptr;
}
// No binding has been found. Declare a variable on the global object.
return scope->AsDeclarationScope()->DeclareDynamicGlobal(
proxy->raw_name(), NORMAL_VARIABLE,
mode == kDeserializedScope ? cache_scope : scope);
}
template Variable* Scope::Lookup<Scope::kParsedScope>(
VariableProxy* proxy, Scope* scope, Scope* outer_scope_end,
Scope* cache_scope, bool force_context_allocation);
template Variable* Scope::Lookup<Scope::kDeserializedScope>(
VariableProxy* proxy, Scope* scope, Scope* outer_scope_end,
Scope* cache_scope, bool force_context_allocation);
Variable* Scope::LookupWith(VariableProxy* proxy, Scope* scope,
Scope* outer_scope_end, Scope* cache_scope,
bool force_context_allocation) {
DCHECK(scope->is_with_scope());
Variable* var =
scope->outer_scope_->scope_info_.is_null()
? Lookup<kParsedScope>(proxy, scope->outer_scope_, outer_scope_end,
nullptr, force_context_allocation)
: Lookup<kDeserializedScope>(proxy, scope->outer_scope_,
outer_scope_end, cache_scope);
if (var == nullptr) return var;
// The current scope is a with scope, so the variable binding can not be
// statically resolved. However, note that it was necessary to do a lookup
// in the outer scope anyway, because if a binding exists in an outer
// scope, the associated variable has to be marked as potentially being
// accessed from inside of an inner with scope (the property may not be in
// the 'with' object).
if (!var->is_dynamic() && var->IsUnallocated()) {
DCHECK(!scope->already_resolved_);
var->set_is_used();
var->ForceContextAllocation();
if (proxy->is_assigned()) var->SetMaybeAssigned();
}
Scope* target_scope;
if (scope->deserialized_scope_uses_external_cache()) {
DCHECK_NOT_NULL(cache_scope);
cache_scope->variables_.Remove(var);
target_scope = cache_scope;
} else {
target_scope = scope;
}
Variable* dynamic =
target_scope->NonLocal(proxy->raw_name(), VariableMode::kDynamic);
dynamic->set_local_if_not_shadowed(var);
return dynamic;
}
Variable* Scope::LookupSloppyEval(VariableProxy* proxy, Scope* scope,
Scope* outer_scope_end, Scope* cache_scope,
bool force_context_allocation) {
DCHECK(scope->is_declaration_scope() &&
scope->AsDeclarationScope()->sloppy_eval_can_extend_vars());
// If we're compiling eval, it's possible that the outer scope is the first
// ScopeInfo-backed scope. We use the next declaration scope as the cache for
// this case, to avoid complexity around sloppy block function hoisting and
// conflict detection through catch scopes in the eval.
Scope* entry_cache = cache_scope == nullptr
? scope->outer_scope()->GetNonEvalDeclarationScope()
: cache_scope;
Variable* var =
scope->outer_scope_->scope_info_.is_null()
? Lookup<kParsedScope>(proxy, scope->outer_scope_, outer_scope_end,
nullptr, force_context_allocation)
: Lookup<kDeserializedScope>(proxy, scope->outer_scope_,
outer_scope_end, entry_cache);
if (var == nullptr) return var;
// We may not want to use the cache scope, change it back to the given scope
// if necessary.
if (!scope->deserialized_scope_uses_external_cache()) {
// For a deserialized scope, we'll be replacing the cache_scope.
DCHECK_IMPLIES(!scope->scope_info_.is_null(), cache_scope != nullptr);
cache_scope = scope;
}
// A variable binding may have been found in an outer scope, but the current
// scope makes a sloppy 'eval' call, so the found variable may not be the
// correct one (the 'eval' may introduce a binding with the same name). In
// that case, change the lookup result to reflect this situation. Only
// scopes that can host var bindings (declaration scopes) need be considered
// here (this excludes block and catch scopes), and variable lookups at
// script scope are always dynamic.
if (var->IsGlobalObjectProperty()) {
Scope* target = cache_scope == nullptr ? scope : cache_scope;
var = target->NonLocal(proxy->raw_name(), VariableMode::kDynamicGlobal);
}
if (var->is_dynamic()) return var;
Variable* invalidated = var;
if (cache_scope != nullptr) cache_scope->variables_.Remove(invalidated);
Scope* target = cache_scope == nullptr ? scope : cache_scope;
var = target->NonLocal(proxy->raw_name(), VariableMode::kDynamicLocal);
var->set_local_if_not_shadowed(invalidated);
return var;
}
void Scope::ResolveVariable(VariableProxy* proxy) {
DCHECK(!proxy->is_resolved());
Variable* var = Lookup<kParsedScope>(proxy, this, nullptr);
DCHECK_NOT_NULL(var);
ResolveTo(proxy, var);
}
namespace {
void SetNeedsHoleCheck(Variable* var, VariableProxy* proxy) {
proxy->set_needs_hole_check();
var->ForceHoleInitialization();
}
void UpdateNeedsHoleCheck(Variable* var, VariableProxy* proxy, Scope* scope) {
if (var->mode() == VariableMode::kDynamicLocal) {
// Dynamically introduced variables never need a hole check (since they're
// VariableMode::kVar bindings, either from var or function declarations),
// but the variable they shadow might need a hole check, which we want to do
// if we decide that no shadowing variable was dynamically introoduced.
DCHECK_EQ(kCreatedInitialized, var->initialization_flag());
return UpdateNeedsHoleCheck(var->local_if_not_shadowed(), proxy, scope);
}
if (var->initialization_flag() == kCreatedInitialized) return;
// It's impossible to eliminate module import hole checks here, because it's
// unknown at compilation time whether the binding referred to in the
// exporting module itself requires hole checks.
if (var->location() == VariableLocation::MODULE && !var->IsExport()) {
return SetNeedsHoleCheck(var, proxy);
}
// Check if the binding really needs an initialization check. The check
// can be skipped in the following situation: we have a VariableMode::kLet or
// VariableMode::kConst binding, both the Variable and the VariableProxy have
// the same declaration scope (i.e. they are both in global code, in the same
// function or in the same eval code), the VariableProxy is in the source
// physically located after the initializer of the variable, and that the
// initializer cannot be skipped due to a nonlinear scope.
//
// The condition on the closure scopes is a conservative check for
// nested functions that access a binding and are called before the
// binding is initialized:
// function() { f(); let x = 1; function f() { x = 2; } }
//
// The check cannot be skipped on non-linear scopes, namely switch
// scopes, to ensure tests are done in cases like the following:
// switch (1) { case 0: let x = 2; case 1: f(x); }
// The scope of the variable needs to be checked, in case the use is
// in a sub-block which may be linear.
if (var->scope()->GetClosureScope() != scope->GetClosureScope()) {
return SetNeedsHoleCheck(var, proxy);
}
// We should always have valid source positions.
DCHECK_NE(var->initializer_position(), kNoSourcePosition);
DCHECK_NE(proxy->position(), kNoSourcePosition);
if (var->scope()->is_nonlinear() ||
var->initializer_position() >= proxy->position()) {
return SetNeedsHoleCheck(var, proxy);
}
}
} // anonymous namespace
void Scope::ResolveTo(VariableProxy* proxy, Variable* var) {
DCHECK_NOT_NULL(var);
UpdateNeedsHoleCheck(var, proxy, this);
proxy->BindTo(var);
}
void Scope::ResolvePreparsedVariable(VariableProxy* proxy, Scope* scope,
Scope* end) {
// Resolve the variable in all parsed scopes to force context allocation.
for (; scope != end; scope = scope->outer_scope_) {
Variable* var = scope->LookupLocal(proxy->raw_name());
if (var != nullptr) {
var->set_is_used();
if (!var->is_dynamic()) {
var->ForceContextAllocation();
if (proxy->is_assigned()) var->SetMaybeAssigned();
return;
}
}
}
}
bool Scope::ResolveVariablesRecursively(Scope* end) {
// Lazy parsed declaration scopes are already partially analyzed. If there are
// unresolved references remaining, they just need to be resolved in outer
// scopes.
if (WasLazilyParsed(this)) {
DCHECK_EQ(variables_.occupancy(), 0);
// Resolve in all parsed scopes except for the script scope.
if (!end->is_script_scope()) end = end->outer_scope();
for (VariableProxy* proxy : unresolved_list_) {
ResolvePreparsedVariable(proxy, outer_scope(), end);
}
} else {
// Resolve unresolved variables for this scope.
for (VariableProxy* proxy : unresolved_list_) {
ResolveVariable(proxy);
}
// Resolve unresolved variables for inner scopes.
for (Scope* scope = inner_scope_; scope != nullptr;
scope = scope->sibling_) {
if (!scope->ResolveVariablesRecursively(end)) return false;
}
}
return true;
}
bool Scope::MustAllocate(Variable* var) {
DCHECK(var->location() != VariableLocation::MODULE);
// Give var a read/write use if there is a chance it might be accessed
// via an eval() call. This is only possible if the variable has a
// visible name.
if (!var->raw_name()->IsEmpty() &&
(inner_scope_calls_eval_ || is_catch_scope() || is_script_scope())) {
var->set_is_used();
if (inner_scope_calls_eval_ && !var->is_this()) var->SetMaybeAssigned();
}
DCHECK(!var->has_forced_context_allocation() || var->is_used());
// Global variables do not need to be allocated.
return !var->IsGlobalObjectProperty() && var->is_used();
}
bool Scope::MustAllocateInContext(Variable* var) {
// If var is accessed from an inner scope, or if there is a possibility
// that it might be accessed from the current or an inner scope (through
// an eval() call or a runtime with lookup), it must be allocated in the
// context.
//
// Temporary variables are always stack-allocated. Catch-bound variables are
// always context-allocated.
VariableMode mode = var->mode();
if (mode == VariableMode::kTemporary) return false;
if (is_catch_scope()) return true;
if (is_script_scope() || is_eval_scope()) {
if (IsLexicalVariableMode(mode)) {
return true;
}
}
return var->has_forced_context_allocation() || inner_scope_calls_eval_;
}
void Scope::AllocateStackSlot(Variable* var) {
if (is_block_scope()) {
outer_scope()->GetDeclarationScope()->AllocateStackSlot(var);
} else {
var->AllocateTo(VariableLocation::LOCAL, num_stack_slots_++);
}
}
void Scope::AllocateHeapSlot(Variable* var) {
var->AllocateTo(VariableLocation::CONTEXT, num_heap_slots_++);
}
void DeclarationScope::AllocateParameterLocals() {
DCHECK(is_function_scope());
bool has_mapped_arguments = false;
if (arguments_ != nullptr) {
DCHECK(!is_arrow_scope());
if (MustAllocate(arguments_) && !has_arguments_parameter_) {
// 'arguments' is used and does not refer to a function
// parameter of the same name. If the arguments object
// aliases formal parameters, we conservatively allocate
// them specially in the loop below.
has_mapped_arguments =
GetArgumentsType() == CreateArgumentsType::kMappedArguments;
} else {
// 'arguments' is unused. Tell the code generator that it does not need to
// allocate the arguments object by nulling out arguments_.
arguments_ = nullptr;
}
}
// The same parameter may occur multiple times in the parameters_ list.
// If it does, and if it is not copied into the context object, it must
// receive the highest parameter index for that parameter; thus iteration
// order is relevant!
for (int i = num_parameters() - 1; i >= 0; --i) {
Variable* var = params_[i];
DCHECK_NOT_NULL(var);
DCHECK(!has_rest_ || var != rest_parameter());
DCHECK_EQ(this, var->scope());
if (has_mapped_arguments) {
var->set_is_used();
var->SetMaybeAssigned();
var->ForceContextAllocation();
}
AllocateParameter(var, i);
}
}
void DeclarationScope::AllocateParameter(Variable* var, int index) {
if (!MustAllocate(var)) return;
if (has_forced_context_allocation_for_parameters() ||
MustAllocateInContext(var)) {
DCHECK(var->IsUnallocated() || var->IsContextSlot());
if (var->IsUnallocated()) AllocateHeapSlot(var);
} else {
DCHECK(var->IsUnallocated() || var->IsParameter());
if (var->IsUnallocated()) {
var->AllocateTo(VariableLocation::PARAMETER, index);
}
}
}
void DeclarationScope::AllocateReceiver() {
if (!has_this_declaration()) return;
DCHECK_NOT_NULL(receiver());
DCHECK_EQ(receiver()->scope(), this);
AllocateParameter(receiver(), -1);
}
void Scope::AllocateNonParameterLocal(Variable* var) {
DCHECK_EQ(var->scope(), this);
if (var->IsUnallocated() && MustAllocate(var)) {
if (MustAllocateInContext(var)) {
AllocateHeapSlot(var);
DCHECK_IMPLIES(is_catch_scope(),
var->index() == Context::THROWN_OBJECT_INDEX);
} else {
AllocateStackSlot(var);
}
}
}
void Scope::AllocateNonParameterLocalsAndDeclaredGlobals() {
if (is_declaration_scope() && AsDeclarationScope()->is_arrow_scope()) {
// In arrow functions, allocate non-temporaries first and then all the
// temporaries to make the local variable ordering stable when reparsing to
// collect source positions.
for (Variable* local : locals_) {
if (local->mode() != VariableMode::kTemporary)
AllocateNonParameterLocal(local);
}
for (Variable* local : locals_) {
if (local->mode() == VariableMode::kTemporary)
AllocateNonParameterLocal(local);
}
} else {
for (Variable* local : locals_) {
AllocateNonParameterLocal(local);
}
}
if (is_declaration_scope()) {
AsDeclarationScope()->AllocateLocals();
}
}
void DeclarationScope::AllocateLocals() {
// For now, function_ must be allocated at the very end. If it gets
// allocated in the context, it must be the last slot in the context,
// because of the current ScopeInfo implementation (see
// ScopeInfo::ScopeInfo(FunctionScope* scope) constructor).
if (function_ != nullptr && MustAllocate(function_)) {
AllocateNonParameterLocal(function_);
} else {
function_ = nullptr;
}
DCHECK(!has_rest_ || !MustAllocate(rest_parameter()) ||
!rest_parameter()->IsUnallocated());
if (new_target_ != nullptr && !MustAllocate(new_target_)) {
new_target_ = nullptr;
}
NullifyRareVariableIf(RareVariable::kThisFunction,
[=](Variable* var) { return !MustAllocate(var); });
}
void ModuleScope::AllocateModuleVariables() {
for (const auto& it : module()->regular_imports()) {
Variable* var = LookupLocal(it.first);
var->AllocateTo(VariableLocation::MODULE, it.second->cell_index);
DCHECK(!var->IsExport());
}
for (const auto& it : module()->regular_exports()) {
Variable* var = LookupLocal(it.first);
var->AllocateTo(VariableLocation::MODULE, it.second->cell_index);
DCHECK(var->IsExport());
}
}
void Scope::AllocateVariablesRecursively() {
this->ForEach([](Scope* scope) -> Iteration {
DCHECK(!scope->already_resolved_);
if (WasLazilyParsed(scope)) return Iteration::kContinue;
DCHECK_EQ(scope->ContextHeaderLength(), scope->num_heap_slots_);
// Allocate variables for this scope.
// Parameters must be allocated first, if any.
if (scope->is_declaration_scope()) {
if (scope->is_function_scope()) {
scope->AsDeclarationScope()->AllocateParameterLocals();
}
scope->AsDeclarationScope()->AllocateReceiver();
}
scope->AllocateNonParameterLocalsAndDeclaredGlobals();
// Force allocation of a context for this scope if necessary. For a 'with'
// scope and for a function scope that makes an 'eval' call we need a
// context, even if no local variables were statically allocated in the
// scope. Likewise for modules and function scopes representing asm.js
// modules. Also force a context, if the scope is stricter than the outer
// scope.
bool must_have_context =
scope->is_with_scope() || scope->is_module_scope() ||
#if V8_ENABLE_WEBASSEMBLY
scope->IsAsmModule() ||
#endif // V8_ENABLE_WEBASSEMBLY
scope->ForceContextForLanguageMode() ||
(scope->is_function_scope() &&
scope->AsDeclarationScope()->sloppy_eval_can_extend_vars()) ||
(scope->is_block_scope() && scope->is_declaration_scope() &&
scope->AsDeclarationScope()->sloppy_eval_can_extend_vars());
// If we didn't allocate any locals in the local context, then we only
// need the minimal number of slots if we must have a context.
if (scope->num_heap_slots_ == scope->ContextHeaderLength() &&
!must_have_context) {
scope->num_heap_slots_ = 0;
}
// Allocation done.
DCHECK(scope->num_heap_slots_ == 0 ||
scope->num_heap_slots_ >= scope->ContextHeaderLength());
return Iteration::kDescend;
});
}
template <typename IsolateT>
void Scope::AllocateScopeInfosRecursively(IsolateT* isolate,
MaybeHandle<ScopeInfo> outer_scope) {
DCHECK(scope_info_.is_null());
MaybeHandle<ScopeInfo> next_outer_scope = outer_scope;
if (NeedsScopeInfo()) {
scope_info_ = ScopeInfo::Create(isolate, zone(), this, outer_scope);
// The ScopeInfo chain should mirror the context chain, so we only link to
// the next outer scope that needs a context.
if (NeedsContext()) next_outer_scope = scope_info_;
}
// Allocate ScopeInfos for inner scopes.
for (Scope* scope = inner_scope_; scope != nullptr; scope = scope->sibling_) {
if (!scope->is_function_scope() ||
scope->AsDeclarationScope()->ShouldEagerCompile()) {
scope->AllocateScopeInfosRecursively(isolate, next_outer_scope);
}
}
}
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) void Scope::
AllocateScopeInfosRecursively<Isolate>(Isolate* isolate,
MaybeHandle<ScopeInfo> outer_scope);
template EXPORT_TEMPLATE_DEFINE(V8_EXPORT_PRIVATE) void Scope::
AllocateScopeInfosRecursively<LocalIsolate>(
LocalIsolate* isolate, MaybeHandle<ScopeInfo> outer_scope);
void DeclarationScope::RecalcPrivateNameContextChain() {
// The outermost scope in a class heritage expression is marked to skip the
// class scope during private name resolution. It is possible, however, that
// either the class scope won't require a Context and ScopeInfo, or the
// outermost scope in the heritage position won't. Simply copying the bit from
// full parse into the ScopeInfo will break lazy compilation. In the former
// case the scope that is marked to skip its outer scope will incorrectly skip
// a different class scope than the one we intended to skip. In the latter
// case variables resolved through an inner scope will incorrectly check the
// class scope since we lost the skip bit from the outermost heritage scope.
//
// This method fixes both cases by, in outermost to innermost order, copying
// the value of the skip bit from outer scopes that don't require a Context.
DCHECK(needs_private_name_context_chain_recalc_);
this->ForEach([](Scope* scope) {
Scope* outer = scope->outer_scope();
if (!outer) return Iteration::kDescend;
if (!outer->NeedsContext()) {
scope->private_name_lookup_skips_outer_class_ =
outer->private_name_lookup_skips_outer_class();
}
if (!scope->is_function_scope() ||
scope->AsDeclarationScope()->ShouldEagerCompile()) {
return Iteration::kDescend;
}
return Iteration::kContinue;
});
}
void DeclarationScope::RecordNeedsPrivateNameContextChainRecalc() {
DCHECK_EQ(GetClosureScope(), this);
DeclarationScope* scope;
for (scope = this; scope != nullptr;
scope = scope->outer_scope() != nullptr
? scope->outer_scope()->GetClosureScope()
: nullptr) {
if (scope->needs_private_name_context_chain_recalc_) return;
scope->needs_private_name_context_chain_recalc_ = true;
}
}
// static
template <typename IsolateT>
void DeclarationScope::AllocateScopeInfos(ParseInfo* info, IsolateT* isolate) {
DeclarationScope* scope = info->literal()->scope();
// No one else should have allocated a scope info for this scope yet.
DCHECK(scope->scope_info_.is_null());
MaybeHandle<ScopeInfo> outer_scope;
if (scope->outer_scope_ != nullptr) {
DCHECK((std::is_same<Isolate, v8::internal::Isolate>::value));
outer_scope = scope->outer_scope_->scope_info_;
}
if (scope->needs_private_name_context_chain_recalc()) {
scope->RecalcPrivateNameContextChain();
}
scope->AllocateScopeInfosRecursively(isolate, outer_scope);
// The debugger expects all shared function infos to contain a scope info.
// Since the top-most scope will end up in a shared function info, make sure
// it has one, even if it doesn't need a scope info.
// TODO(jochen|yangguo): Remove this requirement.
if (scope->scope_info_.is_null()) {
scope->scope_info_ =
ScopeInfo::Create(isolate, scope->zone(), scope, outer_scope);
}
// Ensuring that the outer script scope has a scope info avoids having
// special case for native contexts vs other contexts.
if (info->script_scope() && info->script_scope()->scope_info_.is_null()) {
info->script_scope()->scope_info_ = isolate->factory()->empty_scope_info();
}
}
template V8_EXPORT_PRIVATE void DeclarationScope::AllocateScopeInfos(
ParseInfo* info, Isolate* isolate);
template V8_EXPORT_PRIVATE void DeclarationScope::AllocateScopeInfos(
ParseInfo* info, LocalIsolate* isolate);
int Scope::ContextLocalCount() const {
if (num_heap_slots() == 0) return 0;
Variable* function =
is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
bool is_function_var_in_context =
function != nullptr && function->IsContextSlot();
return num_heap_slots() - ContextHeaderLength() -
(is_function_var_in_context ? 1 : 0);
}
bool IsComplementaryAccessorPair(VariableMode a, VariableMode b) {
switch (a) {
case VariableMode::kPrivateGetterOnly:
return b == VariableMode::kPrivateSetterOnly;
case VariableMode::kPrivateSetterOnly:
return b == VariableMode::kPrivateGetterOnly;
default:
return false;
}
}
Variable* ClassScope::DeclarePrivateName(const AstRawString* name,
VariableMode mode,
IsStaticFlag is_static_flag,
bool* was_added) {
Variable* result = EnsureRareData()->private_name_map.Declare(
zone(), this, name, mode, NORMAL_VARIABLE,
InitializationFlag::kNeedsInitialization, MaybeAssignedFlag::kNotAssigned,
is_static_flag, was_added);
if (*was_added) {
locals_.Add(result);
has_static_private_methods_ |=
(result->is_static() &&
IsPrivateMethodOrAccessorVariableMode(result->mode()));
} else if (IsComplementaryAccessorPair(result->mode(), mode) &&
result->is_static_flag() == is_static_flag) {
*was_added = true;
result->set_mode(VariableMode::kPrivateGetterAndSetter);
}
result->ForceContextAllocation();
return result;
}
Variable* ClassScope::LookupLocalPrivateName(const AstRawString* name) {
RareData* rare_data = GetRareData();
if (rare_data == nullptr) {
return nullptr;
}
return rare_data->private_name_map.Lookup(name);
}
UnresolvedList::Iterator ClassScope::GetUnresolvedPrivateNameTail() {
RareData* rare_data = GetRareData();
if (rare_data == nullptr) {
return UnresolvedList::Iterator();
}
return rare_data->unresolved_private_names.end();
}
void ClassScope::ResetUnresolvedPrivateNameTail(UnresolvedList::Iterator tail) {
RareData* rare_data = GetRareData();
if (rare_data == nullptr ||
rare_data->unresolved_private_names.end() == tail) {
return;
}
bool tail_is_empty = tail == UnresolvedList::Iterator();
if (tail_is_empty) {
// If the saved tail is empty, the list used to be empty, so clear it.
rare_data->unresolved_private_names.Clear();
} else {
rare_data->unresolved_private_names.Rewind(tail);
}
}
void ClassScope::MigrateUnresolvedPrivateNameTail(
AstNodeFactory* ast_node_factory, UnresolvedList::Iterator tail) {
RareData* rare_data = GetRareData();
if (rare_data == nullptr ||
rare_data->unresolved_private_names.end() == tail) {
return;
}
UnresolvedList migrated_names;
// If the saved tail is empty, the list used to be empty, so we should
// migrate everything after the head.
bool tail_is_empty = tail == UnresolvedList::Iterator();
UnresolvedList::Iterator it =
tail_is_empty ? rare_data->unresolved_private_names.begin() : tail;
for (; it != rare_data->unresolved_private_names.end(); ++it) {
VariableProxy* proxy = *it;
VariableProxy* copy = ast_node_factory->CopyVariableProxy(proxy);
migrated_names.Add(copy);
}
// Replace with the migrated copies.
if (tail_is_empty) {
rare_data->unresolved_private_names.Clear();
} else {
rare_data->unresolved_private_names.Rewind(tail);
}
rare_data->unresolved_private_names.Append(std::move(migrated_names));
}
Variable* ClassScope::LookupPrivateNameInScopeInfo(const AstRawString* name) {
DCHECK(!scope_info_.is_null());
DCHECK_NULL(LookupLocalPrivateName(name));
DisallowGarbageCollection no_gc;
String name_handle = *name->string();
VariableLookupResult lookup_result;
int index =
ScopeInfo::ContextSlotIndex(*scope_info_, name_handle, &lookup_result);
if (index < 0) {
return nullptr;
}
DCHECK(IsConstVariableMode(lookup_result.mode));
DCHECK_EQ(lookup_result.init_flag, InitializationFlag::kNeedsInitialization);
DCHECK_EQ(lookup_result.maybe_assigned_flag, MaybeAssignedFlag::kNotAssigned);
// Add the found private name to the map to speed up subsequent
// lookups for the same name.
bool was_added;
Variable* var = DeclarePrivateName(name, lookup_result.mode,
lookup_result.is_static_flag, &was_added);
DCHECK(was_added);
var->AllocateTo(VariableLocation::CONTEXT, index);
return var;
}
Variable* ClassScope::LookupPrivateName(VariableProxy* proxy) {
DCHECK(!proxy->is_resolved());
for (PrivateNameScopeIterator scope_iter(this); !scope_iter.Done();
scope_iter.Next()) {
ClassScope* scope = scope_iter.GetScope();
// Try finding it in the private name map first, if it can't be found,
// try the deseralized scope info.
Variable* var = scope->LookupLocalPrivateName(proxy->raw_name());
if (var == nullptr && !scope->scope_info_.is_null()) {
var = scope->LookupPrivateNameInScopeInfo(proxy->raw_name());
}
if (var != nullptr) {
return var;
}
}
return nullptr;
}
bool ClassScope::ResolvePrivateNames(ParseInfo* info) {
RareData* rare_data = GetRareData();
if (rare_data == nullptr || rare_data->unresolved_private_names.is_empty()) {
return true;
}
UnresolvedList& list = rare_data->unresolved_private_names;
for (VariableProxy* proxy : list) {
Variable* var = LookupPrivateName(proxy);
if (var == nullptr) {
// It's only possible to fail to resolve private names here if
// this is at the top level or the private name is accessed through eval.
DCHECK(info->flags().is_eval() || outer_scope_->is_script_scope());
Scanner::Location loc = proxy->location();
info->pending_error_handler()->ReportMessageAt(
loc.beg_pos, loc.end_pos,
MessageTemplate::kInvalidPrivateFieldResolution, proxy->raw_name());
return false;
} else {
proxy->BindTo(var);
}
}
// By now all unresolved private names should be resolved so
// clear the list.
list.Clear();
return true;
}
VariableProxy* ClassScope::ResolvePrivateNamesPartially() {
RareData* rare_data = GetRareData();
if (rare_data == nullptr || rare_data->unresolved_private_names.is_empty()) {
return nullptr;
}
PrivateNameScopeIterator private_name_scope_iter(this);
private_name_scope_iter.Next();
UnresolvedList& unresolved = rare_data->unresolved_private_names;
bool has_private_names = rare_data->private_name_map.capacity() > 0;
// If the class itself does not have private names, nor does it have
// an outer private name scope, then we are certain any private name access
// inside cannot be resolved.
if (!has_private_names && private_name_scope_iter.Done() &&
!unresolved.is_empty()) {
return unresolved.first();
}
for (VariableProxy* proxy = unresolved.first(); proxy != nullptr;) {
DCHECK(proxy->IsPrivateName());
VariableProxy* next = proxy->next_unresolved();
unresolved.Remove(proxy);
Variable* var = nullptr;
// If we can find private name in the current class scope, we can bind
// them immediately because it's going to shadow any outer private names.
if (has_private_names) {
var = LookupLocalPrivateName(proxy->raw_name());
if (var != nullptr) {
var->set_is_used();
proxy->BindTo(var);
// If the variable being accessed is a static private method, we need to
// save the class variable in the context to check that the receiver is
// the class during runtime.
has_explicit_static_private_methods_access_ |=
(var->is_static() &&
IsPrivateMethodOrAccessorVariableMode(var->mode()));
}
}
// If the current scope does not have declared private names,
// try looking from the outer class scope later.
if (var == nullptr) {
// There's no outer private name scope so we are certain that the variable
// cannot be resolved later.
if (private_name_scope_iter.Done()) {
return proxy;
}
// The private name may be found later in the outer private name scope, so
// push it to the outer sopce.
private_name_scope_iter.AddUnresolvedPrivateName(proxy);
}
proxy = next;
}
DCHECK(unresolved.is_empty());
return nullptr;
}
Variable* ClassScope::DeclareBrandVariable(AstValueFactory* ast_value_factory,
IsStaticFlag is_static_flag,
int class_token_pos) {
DCHECK_IMPLIES(GetRareData() != nullptr, GetRareData()->brand == nullptr);
bool was_added;
Variable* brand = Declare(zone(), ast_value_factory->dot_brand_string(),
VariableMode::kConst, NORMAL_VARIABLE,
InitializationFlag::kNeedsInitialization,
MaybeAssignedFlag::kNotAssigned, &was_added);
DCHECK(was_added);
brand->set_is_static_flag(is_static_flag);
brand->ForceContextAllocation();
brand->set_is_used();
EnsureRareData()->brand = brand;
brand->set_initializer_position(class_token_pos);
return brand;
}
Variable* ClassScope::DeclareClassVariable(AstValueFactory* ast_value_factory,
const AstRawString* name,
int class_token_pos) {
DCHECK_NULL(class_variable_);
bool was_added;
class_variable_ =
Declare(zone(), name == nullptr ? ast_value_factory->dot_string() : name,
VariableMode::kConst, NORMAL_VARIABLE,
InitializationFlag::kNeedsInitialization,
MaybeAssignedFlag::kMaybeAssigned, &was_added);
DCHECK(was_added);
class_variable_->set_initializer_position(class_token_pos);
return class_variable_;
}
PrivateNameScopeIterator::PrivateNameScopeIterator(Scope* start)
: start_scope_(start), current_scope_(start) {
if (!start->is_class_scope() || start->AsClassScope()->IsParsingHeritage()) {
Next();
}
}
void PrivateNameScopeIterator::Next() {
DCHECK(!Done());
Scope* inner = current_scope_;
Scope* scope = inner->outer_scope();
while (scope != nullptr) {
if (scope->is_class_scope()) {
if (!inner->private_name_lookup_skips_outer_class()) {
current_scope_ = scope;
return;
}
skipped_any_scopes_ = true;
}
inner = scope;
scope = scope->outer_scope();
}
current_scope_ = nullptr;
}
void PrivateNameScopeIterator::AddUnresolvedPrivateName(VariableProxy* proxy) {
// During a reparse, current_scope_->already_resolved_ may be true here,
// because the class scope is deserialized while the function scope inside may
// be new.
DCHECK(!proxy->is_resolved());
DCHECK(proxy->IsPrivateName());
GetScope()->EnsureRareData()->unresolved_private_names.Add(proxy);
// Any closure scope that contain uses of private names that skips over a
// class scope due to heritage expressions need private name context chain
// recalculation, since not all scopes require a Context or ScopeInfo. See
// comment in DeclarationScope::RecalcPrivateNameContextChain.
if (V8_UNLIKELY(skipped_any_scopes_)) {
start_scope_->GetClosureScope()->RecordNeedsPrivateNameContextChainRecalc();
}
}
} // namespace internal
} // namespace v8