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v8/src/scopes.cc
wingo@igalia.com 4eddbacabf Assign bailout and type feedback IDs in a post-pass 
This will allow us to move expressions from one function to another, for
example when the parser determines that a given cover grammar instance
is actually the default value initializer for an arrow function.

This is a re-land of https://codereview.chromium.org/636403003/ with a
fix for the arm64 code generator.

R=svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/663373003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24769 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2014-10-21 12:16:37 +00:00

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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/scopes.h"
#include "src/accessors.h"
#include "src/bootstrapper.h"
#include "src/compiler.h"
#include "src/messages.h"
#include "src/scopeinfo.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, bool is_valid_lhs,
Variable::Kind kind,
InitializationFlag initialization_flag,
MaybeAssignedFlag maybe_assigned_flag,
Interface* interface) {
// 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::Lookup(const_cast<AstRawString*>(name), name->hash(),
true, ZoneAllocationPolicy(zone()));
if (p->value == NULL) {
// The variable has not been declared yet -> insert it.
DCHECK(p->key == name);
p->value = new (zone())
Variable(scope, name, mode, is_valid_lhs, kind, initialization_flag,
maybe_assigned_flag, interface);
}
return reinterpret_cast<Variable*>(p->value);
}
Variable* VariableMap::Lookup(const AstRawString* name) {
Entry* p = ZoneHashMap::Lookup(const_cast<AstRawString*>(name), name->hash(),
false, ZoneAllocationPolicy(NULL));
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(Scope* outer_scope, ScopeType scope_type,
AstValueFactory* ast_value_factory, Zone* zone)
: isolate_(zone->isolate()),
inner_scopes_(4, zone),
variables_(zone),
internals_(4, zone),
temps_(4, zone),
params_(4, zone),
unresolved_(16, zone),
decls_(4, zone),
interface_(FLAG_harmony_modules &&
(scope_type == MODULE_SCOPE || scope_type == GLOBAL_SCOPE)
? Interface::NewModule(zone) : NULL),
already_resolved_(false),
ast_value_factory_(ast_value_factory),
zone_(zone) {
SetDefaults(scope_type, outer_scope, Handle<ScopeInfo>::null());
// The outermost scope must be a global scope.
DCHECK(scope_type == GLOBAL_SCOPE || outer_scope != NULL);
DCHECK(!HasIllegalRedeclaration());
}
Scope::Scope(Scope* inner_scope,
ScopeType scope_type,
Handle<ScopeInfo> scope_info,
AstValueFactory* value_factory,
Zone* zone)
: isolate_(zone->isolate()),
inner_scopes_(4, zone),
variables_(zone),
internals_(4, zone),
temps_(4, zone),
params_(4, zone),
unresolved_(16, zone),
decls_(4, zone),
interface_(NULL),
already_resolved_(true),
ast_value_factory_(value_factory),
zone_(zone) {
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(Scope* inner_scope, const AstRawString* catch_variable_name,
AstValueFactory* value_factory, Zone* zone)
: isolate_(zone->isolate()),
inner_scopes_(1, zone),
variables_(zone),
internals_(0, zone),
temps_(0, zone),
params_(0, zone),
unresolved_(0, zone),
decls_(0, zone),
interface_(NULL),
already_resolved_(true),
ast_value_factory_(value_factory),
zone_(zone) {
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,
true, // Valid left-hand side.
Variable::NORMAL,
kCreatedInitialized);
AllocateHeapSlot(variable);
}
void Scope::SetDefaults(ScopeType scope_type,
Scope* outer_scope,
Handle<ScopeInfo> scope_info) {
outer_scope_ = outer_scope;
scope_type_ = scope_type;
scope_name_ = ast_value_factory_->empty_string();
dynamics_ = NULL;
receiver_ = NULL;
function_ = NULL;
arguments_ = NULL;
illegal_redecl_ = NULL;
scope_inside_with_ = false;
scope_contains_with_ = false;
scope_calls_eval_ = false;
scope_uses_this_ = false;
scope_uses_arguments_ = false;
asm_module_ = false;
asm_function_ = outer_scope != NULL && outer_scope->asm_module_;
// Inherit the strict mode from the parent scope.
strict_mode_ = outer_scope != NULL ? outer_scope->strict_mode_ : SLOPPY;
outer_scope_calls_sloppy_eval_ = false;
inner_scope_calls_eval_ = false;
inner_scope_uses_this_ = 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_modules_ = 0;
module_var_ = NULL,
scope_info_ = scope_info;
start_position_ = RelocInfo::kNoPosition;
end_position_ = RelocInfo::kNoPosition;
if (!scope_info.is_null()) {
scope_calls_eval_ = scope_info->CallsEval();
strict_mode_ = scope_info->strict_mode();
}
}
Scope* Scope::DeserializeScopeChain(Context* context, Scope* global_scope,
Zone* zone) {
// 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(current_scope,
WITH_SCOPE,
Handle<ScopeInfo>::null(),
global_scope->ast_value_factory_,
zone);
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->IsGlobalContext()) {
ScopeInfo* scope_info = ScopeInfo::cast(context->extension());
current_scope = new(zone) Scope(current_scope,
GLOBAL_SCOPE,
Handle<ScopeInfo>(scope_info),
global_scope->ast_value_factory_,
zone);
} else if (context->IsModuleContext()) {
ScopeInfo* scope_info = ScopeInfo::cast(context->module()->scope_info());
current_scope = new(zone) Scope(current_scope,
MODULE_SCOPE,
Handle<ScopeInfo>(scope_info),
global_scope->ast_value_factory_,
zone);
} else if (context->IsFunctionContext()) {
ScopeInfo* scope_info = context->closure()->shared()->scope_info();
current_scope = new(zone) Scope(current_scope,
FUNCTION_SCOPE,
Handle<ScopeInfo>(scope_info),
global_scope->ast_value_factory_,
zone);
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(current_scope,
BLOCK_SCOPE,
Handle<ScopeInfo>(scope_info),
global_scope->ast_value_factory_,
zone);
} else {
DCHECK(context->IsCatchContext());
String* name = String::cast(context->extension());
current_scope = new (zone) Scope(
current_scope,
global_scope->ast_value_factory_->GetString(Handle<String>(name)),
global_scope->ast_value_factory_, zone);
}
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();
}
global_scope->AddInnerScope(current_scope);
global_scope->PropagateScopeInfo(false);
return (innermost_scope == NULL) ? global_scope : innermost_scope;
}
bool Scope::Analyze(CompilationInfo* info) {
DCHECK(info->function() != 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_global_scope() &&
!top->outer_scope()->already_resolved()) {
top = top->outer_scope();
}
// Allocate the variables.
{
AstNodeFactory<AstNullVisitor> ast_node_factory(info->ast_value_factory());
if (!top->AllocateVariables(info, &ast_node_factory)) return false;
}
#ifdef DEBUG
if (info->isolate()->bootstrapper()->IsActive()
? FLAG_print_builtin_scopes
: FLAG_print_scopes) {
scope->Print();
}
if (FLAG_harmony_modules && FLAG_print_interfaces && top->is_global_scope()) {
PrintF("global : ");
top->interface()->Print();
}
#endif
info->PrepareForCompilation(scope);
return true;
}
void Scope::Initialize() {
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.
// Declare and allocate receiver (even for the global scope, and even
// if naccesses_ == 0).
// NOTE: When loading parameters in the global scope, we must take
// care not to access them as properties of the global object, but
// instead load them directly from the stack. Currently, the only
// such parameter is 'this' which is passed on the stack when
// invoking scripts
if (is_declaration_scope()) {
Variable* var =
variables_.Declare(this,
ast_value_factory_->this_string(),
VAR,
false,
Variable::THIS,
kCreatedInitialized);
var->AllocateTo(Variable::PARAMETER, -1);
receiver_ = var;
} else {
DCHECK(outer_scope() != NULL);
receiver_ = outer_scope()->receiver();
}
if (is_function_scope()) {
// Declare 'arguments' variable which exists in all 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,
true,
Variable::ARGUMENTS,
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());
}
return NULL;
}
Variable* Scope::LookupLocal(const AstRawString* name) {
Variable* result = variables_.Lookup(name);
if (result != NULL || scope_info_.is_null()) {
return result;
}
// 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.
Handle<String> name_handle = name->string();
// 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);
// Check context slot lookup.
VariableMode mode;
Variable::Location location = Variable::CONTEXT;
InitializationFlag init_flag;
MaybeAssignedFlag maybe_assigned_flag;
int index = ScopeInfo::ContextSlotIndex(scope_info_, name_handle, &mode,
&init_flag, &maybe_assigned_flag);
if (index < 0) {
// Check parameters.
index = scope_info_->ParameterIndex(*name_handle);
if (index < 0) return NULL;
mode = DYNAMIC;
location = Variable::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;
}
Variable* var = variables_.Declare(this, name, mode, true, Variable::NORMAL,
init_flag, maybe_assigned_flag);
var->AllocateTo(location, index);
return var;
}
Variable* Scope::LookupFunctionVar(const AstRawString* name,
AstNodeFactory<AstNullVisitor>* 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, true /* is valid LHS */,
Variable::NORMAL, kCreatedInitialized);
VariableProxy* proxy = factory->NewVariableProxy(var);
VariableDeclaration* declaration = factory->NewVariableDeclaration(
proxy, mode, this, RelocInfo::kNoPosition);
DeclareFunctionVar(declaration);
var->AllocateTo(Variable::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) {
DCHECK(!already_resolved());
DCHECK(is_function_scope());
Variable* var = variables_.Declare(this, name, mode, true, Variable::NORMAL,
kCreatedInitialized);
params_.Add(var, zone());
return var;
}
Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
InitializationFlag init_flag,
MaybeAssignedFlag maybe_assigned_flag,
Interface* interface) {
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, true, Variable::NORMAL, init_flag,
maybe_assigned_flag, interface);
}
Variable* Scope::DeclareDynamicGlobal(const AstRawString* name) {
DCHECK(is_global_scope());
return variables_.Declare(this,
name,
DYNAMIC_GLOBAL,
true,
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,
false,
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,
true,
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) continue;
const AstRawString* name = decl->proxy()->raw_name();
// Iterate through all scopes until and including the declaration scope.
Scope* previous = NULL;
Scope* current = decl->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());
}
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) {
DCHECK(stack_locals != NULL);
DCHECK(context_locals != 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 (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());
}
}
}
bool Scope::AllocateVariables(CompilationInfo* info,
AstNodeFactory<AstNullVisitor>* 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_global_scope() || is_module_scope())) {
DCHECK(num_modules_ == 0);
AllocateModulesRecursively(this);
}
// 3) Resolve variables.
if (!ResolveVariablesRecursively(info, factory)) return false;
// 4) Allocate variables.
AllocateVariablesRecursively();
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->num_heap_slots_ > 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::HasLazyCompilableOuterContext() const {
Scope* outer = outer_scope_;
if (outer == NULL) return true;
// We have to prevent lazy compilation if this scope is inside a with scope
// and all declaration scopes between them have empty contexts. Such
// declaration scopes may become invisible during scope info deserialization.
outer = outer->DeclarationScope();
bool found_non_trivial_declarations = false;
for (const Scope* scope = outer; scope != NULL; scope = scope->outer_scope_) {
if (scope->is_with_scope() && !found_non_trivial_declarations) return false;
if (scope->is_declaration_scope() && scope->num_heap_slots() > 0) {
found_non_trivial_declarations = true;
}
}
return true;
}
bool Scope::AllowsLazyCompilation() const {
return !force_eager_compilation_ && HasLazyCompilableOuterContext();
}
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::GlobalScope() {
Scope* scope = this;
while (!scope->is_global_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() {
if (scope_info_.is_null()) {
scope_info_ = ScopeInfo::Create(this, zone());
}
return scope_info_;
}
void Scope::GetNestedScopeChain(
List<Handle<ScopeInfo> >* chain,
int position) {
if (!is_eval_scope()) chain->Add(Handle<ScopeInfo>(GetScopeInfo()));
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(chain, position);
return;
}
}
}
#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 GLOBAL_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 Variable::UNALLOCATED:
break;
case Variable::PARAMETER:
PrintF("parameter[%d]", var->index());
break;
case Variable::LOCAL:
PrintF("local[%d]", var->index());
break;
case Variable::CONTEXT:
PrintF("context[%d]", var->index());
break;
case Variable::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);
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 (strict_mode() == STRICT) {
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_this_) Indent(n1, "// scope uses 'this'\n");
if (scope_uses_arguments_) Indent(n1, "// scope uses 'arguments'\n");
if (inner_scope_uses_this_) Indent(n1, "// inner scope uses 'this'\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\n", num_heap_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,
true,
Variable::NORMAL,
init_flag);
// Allocate it by giving it a dynamic lookup.
var->AllocateTo(Variable::LOOKUP, -1);
}
return var;
}
Variable* Scope::LookupRecursive(VariableProxy* proxy,
BindingKind* binding_kind,
AstNodeFactory<AstNullVisitor>* 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_global_scope());
}
if (is_with_scope()) {
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()) {
// 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(CompilationInfo* info,
VariableProxy* proxy,
AstNodeFactory<AstNullVisitor>* factory) {
DCHECK(info->global_scope()->is_global_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.
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->global_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 (FLAG_harmony_scoping && strict_mode() == STRICT &&
var->is_const_mode() && proxy->is_assigned()) {
// Assignment to const. Throw a syntax error.
MessageLocation location(
info->script(), proxy->position(), proxy->position());
Isolate* isolate = info->isolate();
Factory* factory = isolate->factory();
Handle<JSArray> array = factory->NewJSArray(0);
Handle<Object> error;
MaybeHandle<Object> maybe_error =
factory->NewSyntaxError("harmony_const_assign", array);
if (maybe_error.ToHandle(&error)) isolate->Throw(*error, &location);
return false;
}
if (FLAG_harmony_modules) {
bool ok;
#ifdef DEBUG
if (FLAG_print_interface_details) {
PrintF("# Resolve %.*s:\n", var->raw_name()->length(),
var->raw_name()->raw_data());
}
#endif
proxy->interface()->Unify(var->interface(), zone(), &ok);
if (!ok) {
#ifdef DEBUG
if (FLAG_print_interfaces) {
PrintF("SCOPES TYPE ERROR\n");
PrintF("proxy: ");
proxy->interface()->Print();
PrintF("var: ");
var->interface()->Print();
}
#endif
// Inconsistent use of module. Throw a syntax error.
// TODO(rossberg): generate more helpful error message.
MessageLocation location(
info->script(), proxy->position(), proxy->position());
Isolate* isolate = info->isolate();
Factory* factory = isolate->factory();
Handle<JSArray> array = factory->NewJSArray(1);
JSObject::SetElement(array, 0, var->name(), NONE, STRICT).Assert();
Handle<Object> error;
MaybeHandle<Object> maybe_error =
factory->NewSyntaxError("module_type_error", array);
if (maybe_error.ToHandle(&error)) isolate->Throw(*error, &location);
return false;
}
}
proxy->BindTo(var);
return true;
}
bool Scope::ResolveVariablesRecursively(
CompilationInfo* info,
AstNodeFactory<AstNullVisitor>* factory) {
DCHECK(info->global_scope()->is_global_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 this/arguments, but do not propagate them out from normal
// functions.
if (!inner->is_function_scope() || inner->is_arrow_scope()) {
if (inner->scope_uses_this_ || inner->inner_scope_uses_this_) {
inner_scope_uses_this_ = true;
}
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_global_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_block_scope() || is_module_scope()) return true;
if (is_global_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() {
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) {
var->AllocateTo(Variable::LOCAL, num_stack_slots_++);
}
void Scope::AllocateHeapSlot(Variable* var) {
var->AllocateTo(Variable::CONTEXT, num_heap_slots_++);
}
void Scope::AllocateParameterLocals() {
DCHECK(is_function_scope());
Variable* arguments = LookupLocal(ast_value_factory_->arguments_string());
DCHECK(arguments != NULL); // functions have 'arguments' declared implicitly
bool uses_sloppy_arguments = false;
if (MustAllocate(arguments) && !HasArgumentsParameter()) {
// '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 = strict_mode() == SLOPPY;
}
// 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];
DCHECK(var->scope() == this);
if (uses_sloppy_arguments || has_forced_context_allocation()) {
// Force context allocation of the parameter.
var->ForceContextAllocation();
}
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(Variable::PARAMETER, i);
}
}
}
}
}
void Scope::AllocateNonParameterLocal(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::AllocateNonParameterLocals() {
// All variables that have no rewrite yet are non-parameter locals.
for (int i = 0; i < temps_.length(); i++) {
AllocateNonParameterLocal(temps_[i]);
}
for (int i = 0; i < internals_.length(); i++) {
AllocateNonParameterLocal(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(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_ != NULL) {
AllocateNonParameterLocal(function_->proxy()->var());
}
}
void Scope::AllocateVariablesRecursively() {
// Allocate variables for inner scopes.
for (int i = 0; i < inner_scopes_.length(); i++) {
inner_scopes_[i]->AllocateVariablesRecursively();
}
// 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_stack_slots_ = 0;
num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
// Allocate variables for this scope.
// Parameters must be allocated first, if any.
if (is_function_scope()) AllocateParameterLocals();
AllocateNonParameterLocals();
// 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_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::AllocateModulesRecursively(Scope* host_scope) {
if (already_resolved()) return;
if (is_module_scope()) {
DCHECK(interface_->IsFrozen());
DCHECK(module_var_ == NULL);
module_var_ =
host_scope->NewInternal(ast_value_factory_->dot_module_string());
++host_scope->num_modules_;
}
for (int i = 0; i < inner_scopes_.length(); i++) {
Scope* inner_scope = inner_scopes_.at(i);
inner_scope->AllocateModulesRecursively(host_scope);
}
}
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;
return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
(function_ != NULL && function_->proxy()->var()->IsContextSlot() ? 1 : 0);
}
} } // namespace v8::internal
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