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chromium / v8 / v8 / fa94ca3ea422bbdc5a2b0d2ad42f7438456a95a9 / . / src / scopes.cc
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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/v8.h"
#include "src/accessors.h"
#include "src/bootstrapper.h"
#include "src/messages.h"
#include "src/parser.h"
#include "src/scopeinfo.h"
#include "src/scopes.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.
VariableMap::VariableMap(Zone* zone)
: ZoneHashMap(ZoneHashMap::PointersMatch, 8, ZoneAllocationPolicy(zone)),
zone_(zone) {}
VariableMap::~VariableMap() {}
Variable* VariableMap::Declare(Scope* scope, const AstRawString* name,
VariableMode mode, Variable::Kind kind,
InitializationFlag initialization_flag,
MaybeAssignedFlag maybe_assigned_flag,
int declaration_group_start) {
// 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(),
ZoneAllocationPolicy(zone()));
if (p->value == NULL) {
// The variable has not been declared yet -> insert it.
DCHECK(p->key == name);
if (kind == Variable::CLASS) {
p->value = new (zone())
ClassVariable(scope, name, mode, initialization_flag,
maybe_assigned_flag, declaration_group_start);
} else {
p->value = new (zone()) Variable(
scope, name, mode, kind, initialization_flag, maybe_assigned_flag);
}
}
return reinterpret_cast<Variable*>(p->value);
}
Variable* VariableMap::Lookup(const AstRawString* name) {
Entry* p = ZoneHashMap::Lookup(const_cast<AstRawString*>(name), name->hash());
if (p != NULL) {
DCHECK(reinterpret_cast<const AstRawString*>(p->key) == name);
DCHECK(p->value != NULL);
return reinterpret_cast<Variable*>(p->value);
}
return NULL;
}
// ----------------------------------------------------------------------------
// Implementation of Scope
Scope::Scope(Zone* zone, Scope* outer_scope, ScopeType scope_type,
AstValueFactory* ast_value_factory, FunctionKind function_kind)
: inner_scopes_(4, zone),
variables_(zone),
internals_(4, zone),
temps_(4, zone),
params_(4, zone),
unresolved_(16, zone),
decls_(4, zone),
module_descriptor_(
scope_type == MODULE_SCOPE ? ModuleDescriptor::New(zone) : NULL),
already_resolved_(false),
ast_value_factory_(ast_value_factory),
zone_(zone),
class_declaration_group_start_(-1) {
SetDefaults(scope_type, outer_scope, Handle<ScopeInfo>::null(),
function_kind);
// The outermost scope must be a script scope.
DCHECK(scope_type == SCRIPT_SCOPE || outer_scope != NULL);
DCHECK(!HasIllegalRedeclaration());
}
Scope::Scope(Zone* zone, Scope* inner_scope, ScopeType scope_type,
Handle<ScopeInfo> scope_info, AstValueFactory* value_factory)
: inner_scopes_(4, zone),
variables_(zone),
internals_(4, zone),
temps_(4, zone),
params_(4, zone),
unresolved_(16, zone),
decls_(4, zone),
module_descriptor_(NULL),
already_resolved_(true),
ast_value_factory_(value_factory),
zone_(zone),
class_declaration_group_start_(-1) {
SetDefaults(scope_type, NULL, scope_info);
if (!scope_info.is_null()) {
num_heap_slots_ = scope_info_->ContextLength();
}
// Ensure at least MIN_CONTEXT_SLOTS to indicate a materialized context.
num_heap_slots_ = Max(num_heap_slots_,
static_cast<int>(Context::MIN_CONTEXT_SLOTS));
AddInnerScope(inner_scope);
}
Scope::Scope(Zone* zone, Scope* inner_scope,
const AstRawString* catch_variable_name,
AstValueFactory* value_factory)
: inner_scopes_(1, zone),
variables_(zone),
internals_(0, zone),
temps_(0, zone),
params_(0, zone),
unresolved_(0, zone),
decls_(0, zone),
module_descriptor_(NULL),
already_resolved_(true),
ast_value_factory_(value_factory),
zone_(zone),
class_declaration_group_start_(-1) {
SetDefaults(CATCH_SCOPE, NULL, Handle<ScopeInfo>::null());
AddInnerScope(inner_scope);
++num_var_or_const_;
num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
Variable* variable = variables_.Declare(this,
catch_variable_name,
VAR,
Variable::NORMAL,
kCreatedInitialized);
AllocateHeapSlot(variable);
}
void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
Handle<ScopeInfo> scope_info,
FunctionKind function_kind) {
outer_scope_ = outer_scope;
scope_type_ = scope_type;
is_declaration_scope_ =
is_eval_scope() || is_function_scope() ||
is_module_scope() || is_script_scope();
function_kind_ = function_kind;
scope_name_ = ast_value_factory_->empty_string();
dynamics_ = nullptr;
receiver_ = nullptr;
new_target_ = nullptr;
function_ = nullptr;
arguments_ = nullptr;
this_function_ = nullptr;
illegal_redecl_ = nullptr;
scope_inside_with_ = false;
scope_contains_with_ = false;
scope_calls_eval_ = false;
scope_uses_arguments_ = false;
scope_uses_super_property_ = false;
asm_module_ = false;
asm_function_ = outer_scope != NULL && outer_scope->asm_module_;
// Inherit the language mode from the parent scope.
language_mode_ = outer_scope != NULL ? outer_scope->language_mode_ : SLOPPY;
outer_scope_calls_sloppy_eval_ = false;
inner_scope_calls_eval_ = false;
inner_scope_uses_arguments_ = false;
force_eager_compilation_ = false;
force_context_allocation_ = (outer_scope != NULL && !is_function_scope())
? outer_scope->has_forced_context_allocation() : false;
num_var_or_const_ = 0;
num_stack_slots_ = 0;
num_heap_slots_ = 0;
num_global_slots_ = 0;
num_modules_ = 0;
module_var_ = NULL,
rest_parameter_ = NULL;
rest_index_ = -1;
scope_info_ = scope_info;
start_position_ = RelocInfo::kNoPosition;
end_position_ = RelocInfo::kNoPosition;
if (!scope_info.is_null()) {
scope_calls_eval_ = scope_info->CallsEval();
language_mode_ = scope_info->language_mode();
function_kind_ = scope_info->function_kind();
}
}
Scope* Scope::DeserializeScopeChain(Isolate* isolate, Zone* zone,
Context* context, Scope* script_scope) {
// Reconstruct the outer scope chain from a closure's context chain.
Scope* current_scope = NULL;
Scope* innermost_scope = NULL;
bool contains_with = false;
while (!context->IsNativeContext()) {
if (context->IsWithContext()) {
Scope* with_scope = new (zone)
Scope(zone, current_scope, WITH_SCOPE, Handle<ScopeInfo>::null(),
script_scope->ast_value_factory_);
current_scope = with_scope;
// All the inner scopes are inside a with.
contains_with = true;
for (Scope* s = innermost_scope; s != NULL; s = s->outer_scope()) {
s->scope_inside_with_ = true;
}
} else if (context->IsScriptContext()) {
ScopeInfo* scope_info = ScopeInfo::cast(context->extension());
current_scope = new (zone) Scope(zone, current_scope, SCRIPT_SCOPE,
Handle<ScopeInfo>(scope_info),
script_scope->ast_value_factory_);
} else if (context->IsModuleContext()) {
ScopeInfo* scope_info = ScopeInfo::cast(context->module()->scope_info());
current_scope = new (zone) Scope(zone, current_scope, MODULE_SCOPE,
Handle<ScopeInfo>(scope_info),
script_scope->ast_value_factory_);
} else if (context->IsFunctionContext()) {
ScopeInfo* scope_info = context->closure()->shared()->scope_info();
current_scope = new (zone) Scope(zone, current_scope, FUNCTION_SCOPE,
Handle<ScopeInfo>(scope_info),
script_scope->ast_value_factory_);
if (scope_info->IsAsmFunction()) current_scope->asm_function_ = true;
if (scope_info->IsAsmModule()) current_scope->asm_module_ = true;
} else if (context->IsBlockContext()) {
ScopeInfo* scope_info = ScopeInfo::cast(context->extension());
current_scope = new (zone)
Scope(zone, current_scope, BLOCK_SCOPE, Handle<ScopeInfo>(scope_info),
script_scope->ast_value_factory_);
} else {
DCHECK(context->IsCatchContext());
String* name = String::cast(context->extension());
current_scope = new (zone) Scope(
zone, current_scope,
script_scope->ast_value_factory_->GetString(Handle<String>(name)),
script_scope->ast_value_factory_);
}
if (contains_with) current_scope->RecordWithStatement();
if (innermost_scope == NULL) innermost_scope = current_scope;
// Forget about a with when we move to a context for a different function.
if (context->previous()->closure() != context->closure()) {
contains_with = false;
}
context = context->previous();
}
script_scope->AddInnerScope(current_scope);
script_scope->PropagateScopeInfo(false);
return (innermost_scope == NULL) ? script_scope : innermost_scope;
}
bool Scope::Analyze(ParseInfo* info) {
DCHECK(info->function() != NULL);
DCHECK(info->scope() == NULL);
Scope* scope = info->function()->scope();
Scope* top = scope;
// Traverse the scope tree up to the first unresolved scope or the global
// scope and start scope resolution and variable allocation from that scope.
while (!top->is_script_scope() &&
!top->outer_scope()->already_resolved()) {
top = top->outer_scope();
}
// Allocate the variables.
{
AstNodeFactory ast_node_factory(info->ast_value_factory());
if (!top->AllocateVariables(info, &ast_node_factory)) {
DCHECK(top->pending_error_handler_.has_pending_error());
top->pending_error_handler_.ThrowPendingError(info->isolate(),
info->script());
return false;
}
}
#ifdef DEBUG
bool native = info->isolate()->bootstrapper()->IsActive();
if (!info->shared_info().is_null()) {
Object* script = info->shared_info()->script();
native = script->IsScript() &&
Script::cast(script)->type()->value() == Script::TYPE_NATIVE;
}
if (native ? FLAG_print_builtin_scopes : FLAG_print_scopes) scope->Print();
#endif
info->set_scope(scope);
return true;
}
void Scope::Initialize() {
bool subclass_constructor = IsSubclassConstructor(function_kind_);
DCHECK(!already_resolved());
// Add this scope as a new inner scope of the outer scope.
if (outer_scope_ != NULL) {
outer_scope_->inner_scopes_.Add(this, zone());
scope_inside_with_ = outer_scope_->scope_inside_with_ || is_with_scope();
} else {
scope_inside_with_ = is_with_scope();
}
// Declare convenience variables and the receiver.
if (is_declaration_scope() && has_this_declaration()) {
Variable* var = variables_.Declare(
this, ast_value_factory_->this_string(),
subclass_constructor ? CONST : VAR, Variable::THIS,
subclass_constructor ? kNeedsInitialization : kCreatedInitialized);
receiver_ = var;
}
if (is_function_scope() && !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.
variables_.Declare(this, ast_value_factory_->arguments_string(), VAR,
Variable::ARGUMENTS, kCreatedInitialized);
if (subclass_constructor || FLAG_harmony_new_target) {
variables_.Declare(this, ast_value_factory_->new_target_string(), CONST,
Variable::NORMAL, kCreatedInitialized);
}
if (IsConciseMethod(function_kind_) || IsConstructor(function_kind_) ||
IsAccessorFunction(function_kind_)) {
variables_.Declare(this, ast_value_factory_->this_function_string(),
CONST, Variable::NORMAL, kCreatedInitialized);
}
}
}
Scope* Scope::FinalizeBlockScope() {
DCHECK(is_block_scope());
DCHECK(internals_.is_empty());
DCHECK(temps_.is_empty());
DCHECK(params_.is_empty());
if (num_var_or_const() > 0) return this;
// Remove this scope from outer scope.
for (int i = 0; i < outer_scope_->inner_scopes_.length(); i++) {
if (outer_scope_->inner_scopes_[i] == this) {
outer_scope_->inner_scopes_.Remove(i);
break;
}
}
// Reparent inner scopes.
for (int i = 0; i < inner_scopes_.length(); i++) {
outer_scope()->AddInnerScope(inner_scopes_[i]);
}
// Move unresolved variables
for (int i = 0; i < unresolved_.length(); i++) {
outer_scope()->unresolved_.Add(unresolved_[i], zone());
}
// Propagate usage flags to outer scope.
if (uses_arguments()) outer_scope_->RecordArgumentsUsage();
if (uses_super_property()) outer_scope_->RecordSuperPropertyUsage();
if (scope_calls_eval_) outer_scope_->RecordEvalCall();
return NULL;
}
Variable* Scope::LookupLocal(const AstRawString* name) {
Variable* result = variables_.Lookup(name);
if (result != NULL || scope_info_.is_null()) {
return result;
}
Handle<String> name_handle = name->string();
// 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.
// If we have a serialized scope info, we might find the variable there.
// There should be no local slot with the given name.
DCHECK(scope_info_->StackSlotIndex(*name_handle) < 0 || is_block_scope());
// Check context slot lookup.
VariableMode mode;
VariableLocation location;
InitializationFlag init_flag;
MaybeAssignedFlag maybe_assigned_flag;
int index =
ScopeInfo::ContextSlotIndex(scope_info_, name_handle, &mode, &location,
&init_flag, &maybe_assigned_flag);
if (index < 0) {
// Check parameters.
index = scope_info_->ParameterIndex(*name_handle);
if (index < 0) return NULL;
mode = DYNAMIC;
location = VariableLocation::LOOKUP;
init_flag = kCreatedInitialized;
// Be conservative and flag parameters as maybe assigned. Better information
// would require ScopeInfo to serialize the maybe_assigned bit also for
// parameters.
maybe_assigned_flag = kMaybeAssigned;
} else {
DCHECK(location != VariableLocation::GLOBAL ||
(is_script_scope() && IsDeclaredVariableMode(mode) &&
!IsLexicalVariableMode(mode)));
}
Variable::Kind kind = Variable::NORMAL;
if (location == VariableLocation::CONTEXT &&
index == scope_info_->ReceiverContextSlotIndex()) {
kind = Variable::THIS;
}
// TODO(marja, rossberg): Correctly declare FUNCTION, CLASS, NEW_TARGET, and
// ARGUMENTS bindings as their corresponding Variable::Kind.
Variable* var = variables_.Declare(this, name, mode, kind, init_flag,
maybe_assigned_flag);
var->AllocateTo(location, index);
return var;
}
Variable* Scope::LookupFunctionVar(const AstRawString* name,
AstNodeFactory* factory) {
if (function_ != NULL && function_->proxy()->raw_name() == name) {
return function_->proxy()->var();
} else if (!scope_info_.is_null()) {
// If we are backed by a scope info, try to lookup the variable there.
VariableMode mode;
int index = scope_info_->FunctionContextSlotIndex(*(name->string()), &mode);
if (index < 0) return NULL;
Variable* var = new (zone())
Variable(this, name, mode, Variable::NORMAL, kCreatedInitialized);
VariableProxy* proxy = factory->NewVariableProxy(var);
VariableDeclaration* declaration = factory->NewVariableDeclaration(
proxy, mode, this, RelocInfo::kNoPosition);
DeclareFunctionVar(declaration);
var->AllocateTo(VariableLocation::CONTEXT, index);
return var;
} else {
return NULL;
}
}
Variable* Scope::Lookup(const AstRawString* name) {
for (Scope* scope = this;
scope != NULL;
scope = scope->outer_scope()) {
Variable* var = scope->LookupLocal(name);
if (var != NULL) return var;
}
return NULL;
}
Variable* Scope::DeclareParameter(const AstRawString* name, VariableMode mode,
bool is_rest, bool* is_duplicate) {
DCHECK(!already_resolved());
DCHECK(is_function_scope());
Variable* var;
if (!name->IsEmpty()) {
var = variables_.Declare(this, name, mode, Variable::NORMAL,
kCreatedInitialized);
// TODO(wingo): Avoid O(n^2) check.
*is_duplicate = IsDeclaredParameter(name);
} else {
var = new (zone())
Variable(this, name, TEMPORARY, Variable::NORMAL, kCreatedInitialized);
}
if (is_rest) {
DCHECK_NULL(rest_parameter_);
rest_parameter_ = var;
rest_index_ = num_parameters();
}
params_.Add(var, zone());
return var;
}
Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
InitializationFlag init_flag, Variable::Kind kind,
MaybeAssignedFlag maybe_assigned_flag,
int declaration_group_start) {
DCHECK(!already_resolved());
// This function handles VAR, LET, and CONST modes. DYNAMIC variables are
// introduces during variable allocation, INTERNAL variables are allocated
// explicitly, and TEMPORARY variables are allocated via NewTemporary().
DCHECK(IsDeclaredVariableMode(mode));
++num_var_or_const_;
return variables_.Declare(this, name, mode, kind, init_flag,
maybe_assigned_flag, declaration_group_start);
}
Variable* Scope::DeclareDynamicGlobal(const AstRawString* name) {
DCHECK(is_script_scope());
return variables_.Declare(this,
name,
DYNAMIC_GLOBAL,
Variable::NORMAL,
kCreatedInitialized);
}
void Scope::RemoveUnresolved(VariableProxy* var) {
// Most likely (always?) any variable we want to remove
// was just added before, so we search backwards.
for (int i = unresolved_.length(); i-- > 0;) {
if (unresolved_[i] == var) {
unresolved_.Remove(i);
return;
}
}
}
Variable* Scope::NewInternal(const AstRawString* name) {
DCHECK(!already_resolved());
Variable* var = new(zone()) Variable(this,
name,
INTERNAL,
Variable::NORMAL,
kCreatedInitialized);
internals_.Add(var, zone());
return var;
}
Variable* Scope::NewTemporary(const AstRawString* name) {
DCHECK(!already_resolved());
Variable* var = new(zone()) Variable(this,
name,
TEMPORARY,
Variable::NORMAL,
kCreatedInitialized);
temps_.Add(var, zone());
return var;
}
void Scope::AddDeclaration(Declaration* declaration) {
decls_.Add(declaration, zone());
}
void Scope::SetIllegalRedeclaration(Expression* expression) {
// Record only the first illegal redeclaration.
if (!HasIllegalRedeclaration()) {
illegal_redecl_ = expression;
}
DCHECK(HasIllegalRedeclaration());
}
void Scope::VisitIllegalRedeclaration(AstVisitor* visitor) {
DCHECK(HasIllegalRedeclaration());
illegal_redecl_->Accept(visitor);
}
Declaration* Scope::CheckConflictingVarDeclarations() {
int length = decls_.length();
for (int i = 0; i < length; i++) {
Declaration* decl = decls_[i];
if (decl->mode() != VAR && !is_block_scope()) continue;
const AstRawString* name = decl->proxy()->raw_name();
// Iterate through all scopes until and including the declaration scope.
// If the declaration scope is a (declaration) block scope, also continue
// (that is to handle the special inner scope of functions with
// destructuring parameters, which may not shadow any variables from
// the surrounding function scope).
Scope* previous = NULL;
Scope* current = decl->scope();
// 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 VAR, or any declarations within a declaration block scope
// vs lexical declarations in its surrounding (function) scope.
if (decl->mode() != VAR) current = current->outer_scope_;
do {
// There is a conflict if there exists a non-VAR binding.
Variable* other_var = current->variables_.Lookup(name);
if (other_var != NULL && other_var->mode() != VAR) {
return decl;
}
previous = current;
current = current->outer_scope_;
} while (!previous->is_declaration_scope() || previous->is_block_scope());
}
return NULL;
}
class VarAndOrder {
public:
VarAndOrder(Variable* var, int order) : var_(var), order_(order) { }
Variable* var() const { return var_; }
int order() const { return order_; }
static int Compare(const VarAndOrder* a, const VarAndOrder* b) {
return a->order_ - b->order_;
}
private:
Variable* var_;
int order_;
};
void Scope::CollectStackAndContextLocals(
ZoneList<Variable*>* stack_locals, ZoneList<Variable*>* context_locals,
ZoneList<Variable*>* context_globals,
ZoneList<Variable*>* strong_mode_free_variables) {
DCHECK(stack_locals != NULL);
DCHECK(context_locals != NULL);
DCHECK(context_globals != NULL);
// Collect internals which are always allocated on the heap.
for (int i = 0; i < internals_.length(); i++) {
Variable* var = internals_[i];
if (var->is_used()) {
DCHECK(var->IsContextSlot());
context_locals->Add(var, zone());
}
}
// Collect temporaries which are always allocated on the stack, unless the
// context as a whole has forced context allocation.
for (int i = 0; i < temps_.length(); i++) {
Variable* var = temps_[i];
if (var->is_used()) {
if (var->IsContextSlot()) {
DCHECK(has_forced_context_allocation());
context_locals->Add(var, zone());
} else {
DCHECK(var->IsStackLocal());
stack_locals->Add(var, zone());
}
}
}
// Collect declared local variables.
ZoneList<VarAndOrder> vars(variables_.occupancy(), zone());
for (VariableMap::Entry* p = variables_.Start();
p != NULL;
p = variables_.Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
if (strong_mode_free_variables && var->has_strong_mode_reference() &&
var->mode() == DYNAMIC_GLOBAL) {
strong_mode_free_variables->Add(var, zone());
}
if (var->is_used()) {
vars.Add(VarAndOrder(var, p->order), zone());
}
}
vars.Sort(VarAndOrder::Compare);
int var_count = vars.length();
for (int i = 0; i < var_count; i++) {
Variable* var = vars[i].var();
if (var->IsStackLocal()) {
stack_locals->Add(var, zone());
} else if (var->IsContextSlot()) {
context_locals->Add(var, zone());
} else if (var->IsGlobalSlot()) {
context_globals->Add(var, zone());
}
}
}
bool Scope::AllocateVariables(ParseInfo* info, AstNodeFactory* factory) {
// 1) Propagate scope information.
bool outer_scope_calls_sloppy_eval = false;
if (outer_scope_ != NULL) {
outer_scope_calls_sloppy_eval =
outer_scope_->outer_scope_calls_sloppy_eval() |
outer_scope_->calls_sloppy_eval();
}
PropagateScopeInfo(outer_scope_calls_sloppy_eval);
// 2) Allocate module instances.
if (FLAG_harmony_modules && is_script_scope()) {
DCHECK(num_modules_ == 0);
AllocateModules();
}
// 3) Resolve variables.
if (!ResolveVariablesRecursively(info, factory)) return false;
// 4) Allocate variables.
AllocateVariablesRecursively(info->isolate());
return true;
}
bool Scope::HasTrivialContext() const {
// A function scope has a trivial context if it always is the global
// context. We iteratively scan out the context chain to see if
// there is anything that makes this scope non-trivial; otherwise we
// return true.
for (const Scope* scope = this; scope != NULL; scope = scope->outer_scope_) {
if (scope->is_eval_scope()) return false;
if (scope->scope_inside_with_) return false;
if (scope->ContextLocalCount() > 0) return false;
}
return true;
}
bool Scope::HasTrivialOuterContext() const {
Scope* outer = outer_scope_;
if (outer == NULL) return true;
// Note that the outer context may be trivial in general, but the current
// scope may be inside a 'with' statement in which case the outer context
// for this scope is not trivial.
return !scope_inside_with_ && outer->HasTrivialContext();
}
bool Scope::AllowsLazyParsing() const {
// If we are inside a block scope, we must parse eagerly to find out how
// to allocate variables on the block scope. At this point, declarations may
// not have yet been parsed.
for (const Scope* scope = this; scope != NULL; scope = scope->outer_scope_) {
if (scope->is_block_scope()) return false;
}
return AllowsLazyCompilation();
}
bool Scope::AllowsLazyCompilation() const { return !force_eager_compilation_; }
bool Scope::AllowsLazyCompilationWithoutContext() const {
return !force_eager_compilation_ && HasTrivialOuterContext();
}
int Scope::ContextChainLength(Scope* scope) {
int n = 0;
for (Scope* s = this; s != scope; s = s->outer_scope_) {
DCHECK(s != NULL); // scope must be in the scope chain
if (s->is_with_scope() || s->num_heap_slots() > 0) n++;
// Catch and module scopes always have heap slots.
DCHECK(!s->is_catch_scope() || s->num_heap_slots() > 0);
DCHECK(!s->is_module_scope() || s->num_heap_slots() > 0);
}
return n;
}
Scope* Scope::ScriptScope() {
Scope* scope = this;
while (!scope->is_script_scope()) {
scope = scope->outer_scope();
}
return scope;
}
Scope* Scope::DeclarationScope() {
Scope* scope = this;
while (!scope->is_declaration_scope()) {
scope = scope->outer_scope();
}
return scope;
}
Handle<ScopeInfo> Scope::GetScopeInfo(Isolate* isolate) {
if (scope_info_.is_null()) {
scope_info_ = ScopeInfo::Create(isolate, zone(), this);
}
return scope_info_;
}
void Scope::GetNestedScopeChain(Isolate* isolate,
List<Handle<ScopeInfo> >* chain, int position) {
if (!is_eval_scope()) chain->Add(Handle<ScopeInfo>(GetScopeInfo(isolate)));
for (int i = 0; i < inner_scopes_.length(); i++) {
Scope* scope = inner_scopes_[i];
int beg_pos = scope->start_position();
int end_pos = scope->end_position();
DCHECK(beg_pos >= 0 && end_pos >= 0);
if (beg_pos <= position && position < end_pos) {
scope->GetNestedScopeChain(isolate, chain, position);
return;
}
}
}
void Scope::ReportMessage(int start_position, int end_position,
MessageTemplate::Template message,
const AstRawString* arg) {
// Propagate the error to the topmost scope targeted by this scope analysis
// phase.
Scope* top = this;
while (!top->is_script_scope() && !top->outer_scope()->already_resolved()) {
top = top->outer_scope();
}
top->pending_error_handler_.ReportMessageAt(start_position, end_position,
message, arg, kReferenceError);
}
#ifdef DEBUG
static const char* Header(ScopeType scope_type) {
switch (scope_type) {
case EVAL_SCOPE: return "eval";
case FUNCTION_SCOPE: return "function";
case MODULE_SCOPE: return "module";
case SCRIPT_SCOPE: return "global";
case CATCH_SCOPE: return "catch";
case BLOCK_SCOPE: return "block";
case WITH_SCOPE: return "with";
case ARROW_SCOPE: return "arrow";
}
UNREACHABLE();
return NULL;
}
static void Indent(int n, const char* str) {
PrintF("%*s%s", n, "", str);
}
static void PrintName(const AstRawString* name) {
PrintF("%.*s", name->length(), name->raw_data());
}
static 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::GLOBAL:
PrintF("global[%d]", var->index());
break;
case VariableLocation::LOOKUP:
PrintF("lookup");
break;
}
}
static void PrintVar(int indent, Variable* var) {
if (var->is_used() || !var->IsUnallocated()) {
Indent(indent, Variable::Mode2String(var->mode()));
PrintF(" ");
PrintName(var->raw_name());
PrintF("; // ");
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() == kMaybeAssigned) {
if (comma) PrintF(", ");
PrintF("maybe assigned");
}
PrintF("\n");
}
}
static void PrintMap(int indent, VariableMap* map) {
for (VariableMap::Entry* p = map->Start(); p != NULL; p = map->Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
if (var == NULL) {
Indent(indent, "<?>\n");
} else {
PrintVar(indent, var);
}
}
}
void Scope::Print(int n) {
int n0 = (n > 0 ? n : 0);
int n1 = n0 + 2; // indentation
// Print header.
Indent(n0, Header(scope_type_));
if (!scope_name_->IsEmpty()) {
PrintF(" ");
PrintName(scope_name_);
}
// Print parameters, if any.
if (is_function_scope()) {
PrintF(" (");
for (int i = 0; i < params_.length(); i++) {
if (i > 0) PrintF(", ");
PrintName(params_[i]->raw_name());
}
PrintF(")");
}
PrintF(" { // (%d, %d)\n", start_position(), end_position());
// Function name, if any (named function literals, only).
if (function_ != NULL) {
Indent(n1, "// (local) function name: ");
PrintName(function_->proxy()->raw_name());
PrintF("\n");
}
// Scope info.
if (HasTrivialOuterContext()) {
Indent(n1, "// scope has trivial outer context\n");
}
if (is_strong(language_mode())) {
Indent(n1, "// strong mode scope\n");
} else if (is_strict(language_mode())) {
Indent(n1, "// strict mode scope\n");
}
if (scope_inside_with_) Indent(n1, "// scope inside 'with'\n");
if (scope_contains_with_) Indent(n1, "// scope contains 'with'\n");
if (scope_calls_eval_) Indent(n1, "// scope calls 'eval'\n");
if (scope_uses_arguments_) Indent(n1, "// scope uses 'arguments'\n");
if (scope_uses_super_property_)
Indent(n1, "// scope uses 'super' property\n");
if (inner_scope_uses_arguments_) {
Indent(n1, "// inner scope uses 'arguments'\n");
}
if (outer_scope_calls_sloppy_eval_) {
Indent(n1, "// outer scope calls 'eval' in sloppy context\n");
}
if (inner_scope_calls_eval_) Indent(n1, "// inner scope calls 'eval'\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 (including %d global slots)\n", num_heap_slots_,
num_global_slots_);
}
// Print locals.
if (function_ != NULL) {
Indent(n1, "// function var:\n");
PrintVar(n1, function_->proxy()->var());
}
if (temps_.length() > 0) {
Indent(n1, "// temporary vars:\n");
for (int i = 0; i < temps_.length(); i++) {
PrintVar(n1, temps_[i]);
}
}
if (internals_.length() > 0) {
Indent(n1, "// internal vars:\n");
for (int i = 0; i < internals_.length(); i++) {
PrintVar(n1, internals_[i]);
}
}
if (variables_.Start() != NULL) {
Indent(n1, "// local vars:\n");
PrintMap(n1, &variables_);
}
if (dynamics_ != NULL) {
Indent(n1, "// dynamic vars:\n");
PrintMap(n1, dynamics_->GetMap(DYNAMIC));
PrintMap(n1, dynamics_->GetMap(DYNAMIC_LOCAL));
PrintMap(n1, dynamics_->GetMap(DYNAMIC_GLOBAL));
}
// Print inner scopes (disable by providing negative n).
if (n >= 0) {
for (int i = 0; i < inner_scopes_.length(); i++) {
PrintF("\n");
inner_scopes_[i]->Print(n1);
}
}
Indent(n0, "}\n");
}
#endif // DEBUG
Variable* Scope::NonLocal(const AstRawString* name, VariableMode mode) {
if (dynamics_ == NULL) dynamics_ = new (zone()) DynamicScopePart(zone());
VariableMap* map = dynamics_->GetMap(mode);
Variable* var = map->Lookup(name);
if (var == NULL) {
// Declare a new non-local.
InitializationFlag init_flag = (mode == VAR)
? kCreatedInitialized : kNeedsInitialization;
var = map->Declare(NULL,
name,
mode,
Variable::NORMAL,
init_flag);
// Allocate it by giving it a dynamic lookup.
var->AllocateTo(VariableLocation::LOOKUP, -1);
}
return var;
}
Variable* Scope::LookupRecursive(VariableProxy* proxy,
BindingKind* binding_kind,
AstNodeFactory* factory) {
DCHECK(binding_kind != NULL);
if (already_resolved() && is_with_scope()) {
// Short-cut: if the scope is deserialized from a scope info, variable
// allocation is already fixed. We can simply return with dynamic lookup.
*binding_kind = DYNAMIC_LOOKUP;
return NULL;
}
// Try to find the variable in this scope.
Variable* var = LookupLocal(proxy->raw_name());
// 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.)
if (var != NULL) {
*binding_kind = BOUND;
return var;
}
// We did not find a variable locally. Check against the function variable,
// if any. We can do this for all scopes, since the function variable is
// only present - if at all - for function scopes.
*binding_kind = UNBOUND;
var = LookupFunctionVar(proxy->raw_name(), factory);
if (var != NULL) {
*binding_kind = BOUND;
} else if (outer_scope_ != NULL) {
var = outer_scope_->LookupRecursive(proxy, binding_kind, factory);
if (*binding_kind == BOUND && (is_function_scope() || is_with_scope())) {
var->ForceContextAllocation();
}
} else {
DCHECK(is_script_scope());
}
// "this" can't be shadowed by "eval"-introduced bindings or by "with" scopes.
// TODO(wingo): There are other variables in this category; add them.
bool name_can_be_shadowed = var == nullptr || !var->is_this();
if (is_with_scope() && name_can_be_shadowed) {
DCHECK(!already_resolved());
// 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 != NULL && proxy->is_assigned()) var->set_maybe_assigned();
*binding_kind = DYNAMIC_LOOKUP;
return NULL;
} else if (calls_sloppy_eval() && name_can_be_shadowed) {
// 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.
if (*binding_kind == BOUND) {
*binding_kind = BOUND_EVAL_SHADOWED;
} else if (*binding_kind == UNBOUND) {
*binding_kind = UNBOUND_EVAL_SHADOWED;
}
}
return var;
}
bool Scope::ResolveVariable(ParseInfo* info, VariableProxy* proxy,
AstNodeFactory* factory) {
DCHECK(info->script_scope()->is_script_scope());
// If the proxy is already resolved there's nothing to do
// (functions and consts may be resolved by the parser).
if (proxy->is_resolved()) return true;
// Otherwise, try to resolve the variable.
BindingKind binding_kind;
Variable* var = LookupRecursive(proxy, &binding_kind, factory);
switch (binding_kind) {
case BOUND:
// We found a variable binding.
if (is_strong(language_mode())) {
if (!CheckStrongModeDeclaration(proxy, var)) return false;
}
break;
case BOUND_EVAL_SHADOWED:
// We either found a variable binding that might be shadowed by eval or
// gave up on it (e.g. by encountering a local with the same in the outer
// scope which was not promoted to a context, this can happen if we use
// debugger to evaluate arbitrary expressions at a break point).
if (var->IsGlobalObjectProperty()) {
var = NonLocal(proxy->raw_name(), DYNAMIC_GLOBAL);
} else if (var->is_dynamic()) {
var = NonLocal(proxy->raw_name(), DYNAMIC);
} else {
Variable* invalidated = var;
var = NonLocal(proxy->raw_name(), DYNAMIC_LOCAL);
var->set_local_if_not_shadowed(invalidated);
}
break;
case UNBOUND:
// No binding has been found. Declare a variable on the global object.
var = info->script_scope()->DeclareDynamicGlobal(proxy->raw_name());
break;
case UNBOUND_EVAL_SHADOWED:
// No binding has been found. But some scope makes a sloppy 'eval' call.
var = NonLocal(proxy->raw_name(), DYNAMIC_GLOBAL);
break;
case DYNAMIC_LOOKUP:
// The variable could not be resolved statically.
var = NonLocal(proxy->raw_name(), DYNAMIC);
break;
}
DCHECK(var != NULL);
if (proxy->is_assigned()) var->set_maybe_assigned();
if (is_strong(language_mode())) {
// Record that the variable is referred to from strong mode. Also, record
// the position.
var->RecordStrongModeReference(proxy->position(), proxy->end_position());
}
proxy->BindTo(var);
return true;
}
bool Scope::CheckStrongModeDeclaration(VariableProxy* proxy, Variable* var) {
// Check for declaration-after use (for variables) in strong mode. Note that
// we can only do this in the case where we have seen the declaration. And we
// always allow referencing functions (for now).
// This might happen during lazy compilation; we don't keep track of
// initializer positions for variables stored in ScopeInfo, so we cannot check
// bindings against them. TODO(marja, rossberg): remove this hack.
if (var->initializer_position() == RelocInfo::kNoPosition) return true;
// Allow referencing the class name from methods of that class, even though
// the initializer position for class names is only after the body.
Scope* scope = this;
while (scope) {
if (scope->ClassVariableForMethod() == var) return true;
scope = scope->outer_scope();
}
// Allow references from methods to classes declared later, if we detect no
// problematic dependency cycles. Note that we can be inside multiple methods
// at the same time, and it's enough if we find one where the reference is
// allowed.
if (var->is_class() &&
var->AsClassVariable()->declaration_group_start() >= 0) {
for (scope = this; scope && scope != var->scope();
scope = scope->outer_scope()) {
ClassVariable* class_var = scope->ClassVariableForMethod();
// A method is referring to some other class, possibly declared
// later. Referring to a class declared earlier is always OK and covered
// by the code outside this if. Here we only need to allow special cases
// for referring to a class which is declared later.
// Referring to a class C declared later is OK under the following
// circumstances:
// 1. The class declarations are in a consecutive group with no other
// declarations or statements in between, and
// 2. There is no dependency cycle where the first edge is an
// initialization time dependency (computed property name or extends
// clause) from C to something that depends on this class directly or
// transitively.
if (class_var &&
class_var->declaration_group_start() ==
var->AsClassVariable()->declaration_group_start()) {
return true;
}
// TODO(marja,rossberg): implement the dependency cycle detection. Here we
// undershoot the target and allow referring to any class in the same
// consectuive declaration group.
// The cycle detection can work roughly like this: 1) detect init-time
// references here (they are free variables which are inside the class
// scope but not inside a method scope - no parser changes needed to
// detect them) 2) if we encounter an init-time reference here, allow it,
// but record it for a later dependency cycle check 3) also record
// non-init-time references here 4) after scope analysis is done, analyse
// the dependency cycles: an illegal cycle is one starting with an
// init-time reference and leading back to the starting point with either
// non-init-time and init-time references.
}
}
// If both the use and the declaration are inside an eval scope (possibly
// indirectly), or one of them is, we need to check whether they are inside
// the same eval scope or different ones.
// TODO(marja,rossberg): Detect errors across different evals (depends on the
// future of eval in strong mode).
const Scope* eval_for_use = NearestOuterEvalScope();
const Scope* eval_for_declaration = var->scope()->NearestOuterEvalScope();
if (proxy->position() != RelocInfo::kNoPosition &&
proxy->position() < var->initializer_position() && !var->is_function() &&
eval_for_use == eval_for_declaration) {
DCHECK(proxy->end_position() != RelocInfo::kNoPosition);
ReportMessage(proxy->position(), proxy->end_position(),
MessageTemplate::kStrongUseBeforeDeclaration,
proxy->raw_name());
return false;
}
return true;
}
ClassVariable* Scope::ClassVariableForMethod() const {
// TODO(marja, rossberg): This fails to find a class variable in the following
// cases:
// let A = class { ... }
// It needs to be investigated whether this causes any practical problems.
if (!is_function_scope()) return nullptr;
if (IsInObjectLiteral(function_kind_)) return nullptr;
if (!IsConciseMethod(function_kind_) && !IsConstructor(function_kind_) &&
!IsAccessorFunction(function_kind_)) {
return nullptr;
}
DCHECK_NOT_NULL(outer_scope_);
// The class scope contains at most one variable, the class name.
DCHECK(outer_scope_->variables_.occupancy() <= 1);
if (outer_scope_->variables_.occupancy() == 0) return nullptr;
VariableMap::Entry* p = outer_scope_->variables_.Start();
Variable* var = reinterpret_cast<Variable*>(p->value);
if (!var->is_class()) return nullptr;
return var->AsClassVariable();
}
bool Scope::ResolveVariablesRecursively(ParseInfo* info,
AstNodeFactory* factory) {
DCHECK(info->script_scope()->is_script_scope());
// Resolve unresolved variables for this scope.
for (int i = 0; i < unresolved_.length(); i++) {
if (!ResolveVariable(info, unresolved_[i], factory)) return false;
}
// Resolve unresolved variables for inner scopes.
for (int i = 0; i < inner_scopes_.length(); i++) {
if (!inner_scopes_[i]->ResolveVariablesRecursively(info, factory))
return false;
}
return true;
}
void Scope::PropagateScopeInfo(bool outer_scope_calls_sloppy_eval ) {
if (outer_scope_calls_sloppy_eval) {
outer_scope_calls_sloppy_eval_ = true;
}
bool calls_sloppy_eval =
this->calls_sloppy_eval() || outer_scope_calls_sloppy_eval_;
for (int i = 0; i < inner_scopes_.length(); i++) {
Scope* inner = inner_scopes_[i];
inner->PropagateScopeInfo(calls_sloppy_eval);
if (inner->scope_calls_eval_ || inner->inner_scope_calls_eval_) {
inner_scope_calls_eval_ = true;
}
// If the inner scope is an arrow function, propagate the flags tracking
// usage of arguments/super/this, but do not propagate them out from normal
// functions.
if (!inner->is_function_scope() || inner->is_arrow_scope()) {
if (inner->scope_uses_arguments_ || inner->inner_scope_uses_arguments_) {
inner_scope_uses_arguments_ = true;
}
}
if (inner->force_eager_compilation_) {
force_eager_compilation_ = true;
}
if (asm_module_ && inner->scope_type() == FUNCTION_SCOPE) {
inner->asm_function_ = true;
}
}
}
bool Scope::MustAllocate(Variable* var) {
// 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->is_this() || !var->raw_name()->IsEmpty()) &&
(var->has_forced_context_allocation() || scope_calls_eval_ ||
inner_scope_calls_eval_ || scope_contains_with_ || is_catch_scope() ||
is_block_scope() || is_module_scope() || is_script_scope())) {
var->set_is_used();
if (scope_calls_eval_ || inner_scope_calls_eval_) var->set_maybe_assigned();
}
// 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.
//
// Exceptions: If the scope as a whole has forced context allocation, all
// variables will have context allocation, even temporaries. Otherwise
// temporary variables are always stack-allocated. Catch-bound variables are
// always context-allocated.
if (has_forced_context_allocation()) return true;
if (var->mode() == TEMPORARY) return false;
if (var->mode() == INTERNAL) return true;
if (is_catch_scope() || is_module_scope()) return true;
if (is_script_scope() && IsLexicalVariableMode(var->mode())) return true;
return var->has_forced_context_allocation() ||
scope_calls_eval_ ||
inner_scope_calls_eval_ ||
scope_contains_with_;
}
bool Scope::HasArgumentsParameter(Isolate* isolate) {
for (int i = 0; i < params_.length(); i++) {
if (params_[i]->name().is_identical_to(
isolate->factory()->arguments_string())) {
return true;
}
}
return false;
}
void Scope::AllocateStackSlot(Variable* var) {
if (is_block_scope()) {
outer_scope()->DeclarationScope()->AllocateStackSlot(var);
} else {
var->AllocateTo(VariableLocation::LOCAL, num_stack_slots_++);
}
}
void Scope::AllocateHeapSlot(Variable* var) {
var->AllocateTo(VariableLocation::CONTEXT, num_heap_slots_++);
}
void Scope::AllocateParameterLocals(Isolate* isolate) {
DCHECK(is_function_scope());
Variable* arguments = LookupLocal(ast_value_factory_->arguments_string());
// Functions have 'arguments' declared implicitly in all non arrow functions.
DCHECK(arguments != nullptr || is_arrow_scope());
bool uses_sloppy_arguments = false;
if (arguments != nullptr && MustAllocate(arguments) &&
!HasArgumentsParameter(isolate)) {
// 'arguments' is used. Unless there is also a parameter called
// 'arguments', we must be conservative and allocate all parameters to
// the context assuming they will be captured by the arguments object.
// If we have a parameter named 'arguments', a (new) value is always
// assigned to it via the function invocation. Then 'arguments' denotes
// that specific parameter value and cannot be used to access the
// parameters, which is why we don't need to allocate an arguments
// object in that case.
// We are using 'arguments'. Tell the code generator that is needs to
// allocate the arguments object by setting 'arguments_'.
arguments_ = arguments;
// In strict mode 'arguments' does not alias formal parameters.
// Therefore in strict mode we allocate parameters as if 'arguments'
// were not used.
uses_sloppy_arguments = is_sloppy(language_mode());
}
if (rest_parameter_ && !MustAllocate(rest_parameter_)) {
rest_parameter_ = NULL;
}
// 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 = params_.length() - 1; i >= 0; --i) {
Variable* var = params_[i];
if (var == rest_parameter_) continue;
DCHECK(var->scope() == this);
if (uses_sloppy_arguments || has_forced_context_allocation()) {
// Force context allocation of the parameter.
var->ForceContextAllocation();
}
AllocateParameter(var, i);
}
}
void Scope::AllocateParameter(Variable* var, int index) {
if (MustAllocate(var)) {
if (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);
}
}
} else {
DCHECK(!var->IsGlobalSlot());
}
}
void Scope::AllocateReceiver() {
DCHECK_NOT_NULL(receiver());
DCHECK_EQ(receiver()->scope(), this);
if (has_forced_context_allocation()) {
// Force context allocation of the receiver.
receiver()->ForceContextAllocation();
}
AllocateParameter(receiver(), -1);
}
void Scope::AllocateNonParameterLocal(Isolate* isolate, Variable* var) {
DCHECK(var->scope() == this);
DCHECK(!var->IsVariable(isolate->factory()->dot_result_string()) ||
!var->IsStackLocal());
if (var->IsUnallocated() && MustAllocate(var)) {
if (MustAllocateInContext(var)) {
AllocateHeapSlot(var);
} else {
AllocateStackSlot(var);
}
}
}
void Scope::AllocateDeclaredGlobal(Isolate* isolate, Variable* var) {
DCHECK(var->scope() == this);
DCHECK(!var->IsVariable(isolate->factory()->dot_result_string()) ||
!var->IsStackLocal());
if (var->IsUnallocated()) {
if (var->IsStaticGlobalObjectProperty()) {
DCHECK_EQ(-1, var->index());
DCHECK(var->name()->IsString());
var->AllocateTo(VariableLocation::GLOBAL, num_heap_slots_);
num_global_slots_++;
// Each global variable occupies two slots in the context: for reads
// and writes.
num_heap_slots_ += 2;
} else {
// There must be only DYNAMIC_GLOBAL in the script scope.
DCHECK(!is_script_scope() || DYNAMIC_GLOBAL == var->mode());
}
}
}
void Scope::AllocateNonParameterLocalsAndDeclaredGlobals(Isolate* isolate) {
// All variables that have no rewrite yet are non-parameter locals.
for (int i = 0; i < temps_.length(); i++) {
AllocateNonParameterLocal(isolate, temps_[i]);
}
for (int i = 0; i < internals_.length(); i++) {
AllocateNonParameterLocal(isolate, internals_[i]);
}
ZoneList<VarAndOrder> vars(variables_.occupancy(), zone());
for (VariableMap::Entry* p = variables_.Start();
p != NULL;
p = variables_.Next(p)) {
Variable* var = reinterpret_cast<Variable*>(p->value);
vars.Add(VarAndOrder(var, p->order), zone());
}
vars.Sort(VarAndOrder::Compare);
int var_count = vars.length();
for (int i = 0; i < var_count; i++) {
AllocateNonParameterLocal(isolate, vars[i].var());
}
if (FLAG_global_var_shortcuts) {
for (int i = 0; i < var_count; i++) {
AllocateDeclaredGlobal(isolate, vars[i].var());
}
}
// 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) {
AllocateNonParameterLocal(isolate, function_->proxy()->var());
}
if (rest_parameter_ != nullptr) {
AllocateNonParameterLocal(isolate, rest_parameter_);
}
Variable* new_target_var =
LookupLocal(ast_value_factory_->new_target_string());
if (new_target_var != nullptr && MustAllocate(new_target_var)) {
new_target_ = new_target_var;
}
Variable* this_function_var =
LookupLocal(ast_value_factory_->this_function_string());
if (this_function_var != nullptr && MustAllocate(this_function_var)) {
this_function_ = this_function_var;
}
}
void Scope::AllocateVariablesRecursively(Isolate* isolate) {
if (!already_resolved()) {
num_stack_slots_ = 0;
}
// Allocate variables for inner scopes.
for (int i = 0; i < inner_scopes_.length(); i++) {
inner_scopes_[i]->AllocateVariablesRecursively(isolate);
}
// If scope is already resolved, we still need to allocate
// variables in inner scopes which might not had been resolved yet.
if (already_resolved()) return;
// The number of slots required for variables.
num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
// Allocate variables for this scope.
// Parameters must be allocated first, if any.
if (is_function_scope()) AllocateParameterLocals(isolate);
if (has_this_declaration()) AllocateReceiver();
AllocateNonParameterLocalsAndDeclaredGlobals(isolate);
// 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.
bool must_have_context = is_with_scope() || is_module_scope() ||
(is_function_scope() && calls_sloppy_eval());
// 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 (num_heap_slots_ == Context::MIN_CONTEXT_SLOTS && !must_have_context) {
num_heap_slots_ = 0;
}
// Allocation done.
DCHECK(num_heap_slots_ == 0 || num_heap_slots_ >= Context::MIN_CONTEXT_SLOTS);
}
void Scope::AllocateModules() {
DCHECK(is_script_scope());
DCHECK(!already_resolved());
for (int i = 0; i < inner_scopes_.length(); i++) {
Scope* scope = inner_scopes_.at(i);
if (scope->is_module_scope()) {
DCHECK(!scope->already_resolved());
DCHECK(scope->module_descriptor_->IsFrozen());
DCHECK_NULL(scope->module_var_);
scope->module_var_ = NewInternal(ast_value_factory_->dot_module_string());
++num_modules_;
}
}
}
int Scope::StackLocalCount() const {
return num_stack_slots() -
(function_ != NULL && function_->proxy()->var()->IsStackLocal() ? 1 : 0);
}
int Scope::ContextLocalCount() const {
if (num_heap_slots() == 0) return 0;
bool is_function_var_in_context =
function_ != NULL && function_->proxy()->var()->IsContextSlot();
return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
2 * num_global_slots() - (is_function_var_in_context ? 1 : 0);
}
int Scope::ContextGlobalCount() const { return num_global_slots(); }
} // namespace internal
} // namespace v8