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Commit bb97d27a authored by adamk's avatar adamk Committed by Commit bot
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Replace BindingFlags enum with InitializationFlag enum 

They may have once been different, but they're now redundant with
each other. This simplifies both Context::Lookup and its callers.

Review-Url: https://codereview.chromium.org/2200303002
Cr-Commit-Position: refs/heads/master@{#38261}
parent 83b63c30
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Inline Side-by-side
Showing with 34 additions and 115 deletions
src/contexts.cc
View file @ bb97d27a
......@@ -176,51 +176,14 @@ static Maybe<bool> UnscopableLookup(LookupIterator* it) {
return Just(!blacklist->BooleanValue());
}
static void GetAttributesAndBindingFlags(VariableMode mode,
InitializationFlag init_flag,
PropertyAttributes* attributes,
BindingFlags* binding_flags) {
switch (mode) {
case VAR:
*attributes = NONE;
*binding_flags = BINDING_IS_INITIALIZED;
break;
case LET:
*attributes = NONE;
*binding_flags = (init_flag == kNeedsInitialization)
? BINDING_CHECK_INITIALIZED
: BINDING_IS_INITIALIZED;
break;
case CONST_LEGACY:
DCHECK_EQ(kCreatedInitialized, init_flag);
*attributes = READ_ONLY;
*binding_flags = BINDING_IS_INITIALIZED;
break;
case CONST:
*attributes = READ_ONLY;
*binding_flags = (init_flag == kNeedsInitialization)
? BINDING_CHECK_INITIALIZED
: BINDING_IS_INITIALIZED;
break;
case IMPORT: // TODO(neis): Make sure this is what we want for IMPORT.
case DYNAMIC:
case DYNAMIC_GLOBAL:
case DYNAMIC_LOCAL:
case TEMPORARY:
// Note: Fixed context slots are statically allocated by the compiler.
// Statically allocated variables always have a statically known mode,
// which is the mode with which they were declared when added to the
// scope. Thus, the DYNAMIC mode (which corresponds to dynamically
// declared variables that were introduced through declaration nodes)
// must not appear here.
UNREACHABLE();
break;
}
static PropertyAttributes GetAttributesForMode(VariableMode mode) {
DCHECK(IsDeclaredVariableMode(mode));
return IsImmutableVariableMode(mode) ? READ_ONLY : NONE;
}
Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
int* index, PropertyAttributes* attributes,
BindingFlags* binding_flags,
InitializationFlag* init_flag,
VariableMode* variable_mode) {
Isolate* isolate = GetIsolate();
Handle<Context> context(this, isolate);
......@@ -229,7 +192,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
bool failed_whitelist = false;
*index = kNotFound;
*attributes = ABSENT;
*binding_flags = MISSING_BINDING;
*init_flag = kCreatedInitialized;
*variable_mode = VAR;
if (FLAG_trace_contexts) {
......@@ -270,8 +233,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
}
*index = r.slot_index;
*variable_mode = r.mode;
GetAttributesAndBindingFlags(r.mode, r.init_flag, attributes,
binding_flags);
*attributes = GetAttributesForMode(r.mode);
return ScriptContextTable::GetContext(script_contexts,
r.context_index);
}
......@@ -326,12 +288,10 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
? context->closure()->shared()->scope_info()
: context->scope_info());
VariableMode mode;
InitializationFlag init_flag;
// TODO(sigurds) Figure out whether maybe_assigned_flag should
// be used to compute binding_flags.
InitializationFlag flag;
MaybeAssignedFlag maybe_assigned_flag;
int slot_index = ScopeInfo::ContextSlotIndex(
scope_info, name, &mode, &init_flag, &maybe_assigned_flag);
int slot_index = ScopeInfo::ContextSlotIndex(scope_info, name, &mode,
&flag, &maybe_assigned_flag);
DCHECK(slot_index < 0 || slot_index >= MIN_CONTEXT_SLOTS);
if (slot_index >= 0) {
if (FLAG_trace_contexts) {
......@@ -340,8 +300,8 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
}
*index = slot_index;
*variable_mode = mode;
GetAttributesAndBindingFlags(mode, init_flag, attributes,
binding_flags);
*init_flag = flag;
*attributes = GetAttributesForMode(mode);
return context;
}
......@@ -358,7 +318,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
*index = function_index;
*attributes = READ_ONLY;
DCHECK(mode == CONST_LEGACY || mode == CONST);
*binding_flags = BINDING_IS_INITIALIZED;
*init_flag = kCreatedInitialized;
*variable_mode = mode;
return context;
}
......@@ -372,7 +332,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
}
*index = Context::THROWN_OBJECT_INDEX;
*attributes = NONE;
*binding_flags = BINDING_IS_INITIALIZED;
*init_flag = kCreatedInitialized;
*variable_mode = VAR;
return context;
}
......@@ -391,9 +351,9 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
// Check the original context, but do not follow its context chain.
obj = context->get(WRAPPED_CONTEXT_INDEX);
if (obj->IsContext()) {
Handle<Object> result = Context::cast(obj)->Lookup(
name, DONT_FOLLOW_CHAINS, index, attributes, binding_flags,
variable_mode);
Handle<Object> result =
Context::cast(obj)->Lookup(name, DONT_FOLLOW_CHAINS, index,
attributes, init_flag, variable_mode);
if (!result.is_null()) return result;
}
// Check whitelist. Names that do not pass whitelist shall only resolve
......
src/contexts.h
View file @ bb97d27a
......@@ -25,39 +25,6 @@ enum ContextLookupFlags {
};
// ES5 10.2 defines lexical environments with mutable and immutable bindings.
// Immutable bindings have two states, initialized and uninitialized, and
// their state is changed by the InitializeImmutableBinding method. The
// BindingFlags enum represents information if a binding has definitely been
// initialized. A mutable binding does not need to be checked and thus has
// the BindingFlag BINDING_IS_INITIALIZED.
//
// There is one possibility for legacy immutable bindings:
// * The function name of a named function literal. The binding is immediately
// initialized when entering the function and thus does not need to be
// checked. it gets the BindingFlag BINDING_IS_INITIALIZED.
//
// The harmony proposal for block scoped bindings also introduces the
// uninitialized state for mutable bindings.
// * A 'let' declared variable. They are initialized when evaluating the
// corresponding declaration statement. They need to be checked for being
// initialized and thus get the flag BINDING_CHECK_INITIALIZED.
// * A 'var' declared variable. It is initialized immediately upon creation
// and thus doesn't need to be checked. It gets the flag
// BINDING_IS_INITIALIZED.
// * Catch bound variables, function parameters and variables introduced by
// function declarations are initialized immediately and do not need to be
// checked. Thus they get the flag BINDING_IS_INITIALIZED.
// Accessing an uninitialized binding produces a reference error.
//
// In V8 uninitialized bindings are set to the hole value upon creation and set
// to a different value upon initialization.
enum BindingFlags {
BINDING_IS_INITIALIZED,
BINDING_CHECK_INITIALIZED,
MISSING_BINDING
};
// Heap-allocated activation contexts.
//
// Contexts are implemented as FixedArray objects; the Context
......@@ -507,7 +474,7 @@ class Context: public FixedArray {
// always ABSENT.
Handle<Object> Lookup(Handle<String> name, ContextLookupFlags flags,
int* index, PropertyAttributes* attributes,
BindingFlags* binding_flags,
InitializationFlag* init_flag,
VariableMode* variable_mode);
// Code generation support.
......
src/runtime/runtime-scopes.cc
View file @ bb97d27a
......@@ -266,11 +266,11 @@ Object* DeclareEvalHelper(Isolate* isolate, Handle<String> name,
int index;
PropertyAttributes attributes;
BindingFlags binding_flags;
InitializationFlag init_flag;
VariableMode mode;
// Check for a conflict with a lexically scoped variable
context_arg->Lookup(name, LEXICAL_TEST, &index, &attributes, &binding_flags,
context_arg->Lookup(name, LEXICAL_TEST, &index, &attributes, &init_flag,
&mode);
if (attributes != ABSENT && IsLexicalVariableMode(mode)) {
// ES#sec-evaldeclarationinstantiation 5.a.i.1:
......@@ -283,7 +283,7 @@ Object* DeclareEvalHelper(Isolate* isolate, Handle<String> name,
}
Handle<Object> holder = context->Lookup(name, DONT_FOLLOW_CHAINS, &index,
&attributes, &binding_flags, &mode);
&attributes, &init_flag, &mode);
DCHECK(!isolate->has_pending_exception());
Handle<JSObject> object;
......@@ -772,10 +772,10 @@ RUNTIME_FUNCTION(Runtime_DeleteLookupSlot) {
int index;
PropertyAttributes attributes;
BindingFlags flags;
InitializationFlag flag;
VariableMode mode;
Handle<Object> holder = isolate->context()->Lookup(
name, FOLLOW_CHAINS, &index, &attributes, &flags, &mode);
name, FOLLOW_CHAINS, &index, &attributes, &flag, &mode);
// If the slot was not found the result is true.
if (holder.is_null()) {
......@@ -808,10 +808,10 @@ MaybeHandle<Object> LoadLookupSlot(Handle<String> name,
int index;
PropertyAttributes attributes;
BindingFlags flags;
InitializationFlag flag;
VariableMode mode;
Handle<Object> holder = isolate->context()->Lookup(
name, FOLLOW_CHAINS, &index, &attributes, &flags, &mode);
name, FOLLOW_CHAINS, &index, &attributes, &flag, &mode);
if (isolate->has_pending_exception()) return MaybeHandle<Object>();
if (index != Context::kNotFound) {
......@@ -821,22 +821,14 @@ MaybeHandle<Object> LoadLookupSlot(Handle<String> name,
Handle<Object> receiver = isolate->factory()->undefined_value();
Handle<Object> value = handle(Context::cast(*holder)->get(index), isolate);
// Check for uninitialized bindings.
switch (flags) {
case BINDING_CHECK_INITIALIZED:
if (value->IsTheHole(isolate)) {
THROW_NEW_ERROR(isolate,
NewReferenceError(MessageTemplate::kNotDefined, name),
Object);
}
// FALLTHROUGH
case BINDING_IS_INITIALIZED:
DCHECK(!value->IsTheHole(isolate));
if (receiver_return) *receiver_return = receiver;
return value;
case MISSING_BINDING:
break;
if (flag == kNeedsInitialization && value->IsTheHole(isolate)) {
THROW_NEW_ERROR(isolate,
NewReferenceError(MessageTemplate::kNotDefined, name),
Object);
}
UNREACHABLE();
DCHECK(!value->IsTheHole(isolate));
if (receiver_return) *receiver_return = receiver;
return value;
}
// Otherwise, if the slot was found the holder is a context extension
......@@ -912,10 +904,10 @@ MaybeHandle<Object> StoreLookupSlot(Handle<String> name, Handle<Object> value,
int index;
PropertyAttributes attributes;
BindingFlags flags;
InitializationFlag flag;
VariableMode mode;
Handle<Object> holder =
context->Lookup(name, FOLLOW_CHAINS, &index, &attributes, &flags, &mode);
context->Lookup(name, FOLLOW_CHAINS, &index, &attributes, &flag, &mode);
if (holder.is_null()) {
// In case of JSProxy, an exception might have been thrown.
if (isolate->has_pending_exception()) return MaybeHandle<Object>();
......@@ -923,7 +915,7 @@ MaybeHandle<Object> StoreLookupSlot(Handle<String> name, Handle<Object> value,
// The property was found in a context slot.
if (index != Context::kNotFound) {
if (flags == BINDING_CHECK_INITIALIZED &&
if (flag == kNeedsInitialization &&
Handle<Context>::cast(holder)->is_the_hole(index)) {
THROW_NEW_ERROR(isolate,
NewReferenceError(MessageTemplate::kNotDefined, name),
......
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