Reviewers: rossberg,
Description:
Group lexical context variables for faster look up.
Currently, looking up a lexical context variable requires looking up
the variable name and then checking its mode. This can be a bottleneck
in Runtime_DeclareGlobals, even when no lexical context variables are
declared.
[email protected]
BUG=crbug:517778
LOG=N
Please review this at https://codereview.chromium.org/1281883002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+70, -7 lines):
M src/contexts.h
M src/contexts.cc
M src/objects.h
M src/runtime/runtime-scopes.cc
M src/scopeinfo.cc
M src/scopes.cc
Index: src/contexts.cc
diff --git a/src/contexts.cc b/src/contexts.cc
index
9f39aecd542ca24dbbad3bf7baf1109e853494ba..6bd4fcef11053c6285e02b1a98adda3e4afaf20a
100644
--- a/src/contexts.cc
+++ b/src/contexts.cc
@@ -56,6 +56,19 @@ bool
ScriptContextTable::Lookup(Handle<ScriptContextTable> table,
}
+bool ScriptContextTable::LookupLexical(Handle<ScriptContextTable> table,
+ Handle<String> name) {
+ for (int i = 0; i < table->used(); i++) {
+ Handle<Context> context = GetContext(table, i);
+ DCHECK(context->IsScriptContext());
+ Handle<ScopeInfo> scope_info(ScopeInfo::cast(context->extension()));
+ int slot_index = ScopeInfo::LexicalContextSlotIndex(scope_info, name);
+ if (slot_index >= 0) return true;
+ }
+ return false;
+}
+
+
Context* Context::declaration_context() {
Context* current = this;
while (!current->IsFunctionContext() && !current->IsNativeContext() &&
Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index
9c8dc8a860ab2e86cca55933a9aec93bc5e0f83a..d5b090618f13e06d92070518e743513352363673
100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -244,6 +244,10 @@ class ScriptContextTable : public FixedArray {
LookupResult* result);
MUST_USE_RESULT
+ static bool LookupLexical(Handle<ScriptContextTable> table,
+ Handle<String> name);
+
+ MUST_USE_RESULT
static Handle<ScriptContextTable> Extend(Handle<ScriptContextTable>
table,
Handle<Context> script_context);
Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index
257f0e54c35d198f2c6ee16d605e961702edf4f7..19ca422bf7ce8b5e472d0669d0c2906996a7cc8e
100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -3941,6 +3941,9 @@ class ScopeInfo : public FixedArray {
InitializationFlag* init_flag,
MaybeAssignedFlag* maybe_assigned_flag);
+ static int LexicalContextSlotIndex(Handle<ScopeInfo> scope_info,
+ Handle<String> name);
+
// Lookup the name of a certain context slot by its index.
String* ContextSlotName(int slot_index);
@@ -3985,6 +3988,7 @@ class ScopeInfo : public FixedArray {
V(ParameterCount) \
V(StackLocalCount) \
V(ContextLocalCount) \
+ V(LexicalContextLocalCount) \
V(ContextGlobalCount) \
V(StrongModeFreeVariableCount)
Index: src/runtime/runtime-scopes.cc
diff --git a/src/runtime/runtime-scopes.cc b/src/runtime/runtime-scopes.cc
index
ff7e783393081cbe731a8d5f265a5b0fa852b773..06f84598438dc0e56761499823696dd8ee962269
100644
--- a/src/runtime/runtime-scopes.cc
+++ b/src/runtime/runtime-scopes.cc
@@ -36,9 +36,7 @@ static Object* DeclareGlobals(Isolate* isolate,
Handle<GlobalObject> global,
bool is_const, bool is_function) {
Handle<ScriptContextTable> script_contexts(
global->native_context()->script_context_table());
- ScriptContextTable::LookupResult lookup;
- if (ScriptContextTable::Lookup(script_contexts, name, &lookup) &&
- IsLexicalVariableMode(lookup.mode)) {
+ if (ScriptContextTable::LookupLexical(script_contexts, name)) {
return ThrowRedeclarationError(isolate, name);
}
@@ -624,9 +622,13 @@ static Object* FindNameClash(Handle<ScopeInfo>
scope_info,
for (int var = 0; var < scope_info->ContextLocalCount(); var++) {
Handle<String> name(scope_info->ContextLocalName(var));
VariableMode mode = scope_info->ContextLocalMode(var);
- ScriptContextTable::LookupResult lookup;
- if (ScriptContextTable::Lookup(script_context, name, &lookup)) {
- if (IsLexicalVariableMode(mode) ||
IsLexicalVariableMode(lookup.mode)) {
+ if (IsLexicalVariableMode(mode)) {
+ ScriptContextTable::LookupResult lookup;
+ if (ScriptContextTable::Lookup(script_context, name, &lookup)) {
+ return ThrowRedeclarationError(isolate, name);
+ }
+ } else {
+ if (ScriptContextTable::LookupLexical(script_context, name)) {
return ThrowRedeclarationError(isolate, name);
}
}
Index: src/scopeinfo.cc
diff --git a/src/scopeinfo.cc b/src/scopeinfo.cc
index
e490fd9ce48f11eff84aa20f143f852dfea3d7ac..4c22b0aa17f295d76aca8bcfa0266abf271e9fbe
100644
--- a/src/scopeinfo.cc
+++ b/src/scopeinfo.cc
@@ -149,6 +149,8 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate,
Zone* zone,
// Add context locals' info.
DCHECK(index == scope_info->ContextLocalInfoEntriesIndex());
+ bool encountered_lexical = false;
+ int lexical_context_local_count = 0;
for (int i = 0; i < context_local_count; ++i) {
Variable* var = context_locals[i];
uint32_t value =
@@ -156,8 +158,16 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate,
Zone* zone,
ContextLocalInitFlag::encode(var->initialization_flag()) |
ContextLocalMaybeAssignedFlag::encode(var->maybe_assigned());
scope_info->set(index++, Smi::FromInt(value));
+ if (encountered_lexical) {
+ // Check that context locals are sorted so that lexicals are at the
end.
+ DCHECK(IsLexicalVariableMode(var->mode()));
+ } else if (IsLexicalVariableMode(var->mode())) {
+ lexical_context_local_count = context_local_count - i;
+ }
}
+ scope_info->SetLexicalContextLocalCount(lexical_context_local_count);
+
// Add context globals' info.
DCHECK(index == scope_info->ContextGlobalInfoEntriesIndex());
for (int i = 0; i < context_global_count; ++i) {
@@ -222,6 +232,7 @@ Handle<ScopeInfo>
ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
const int stack_local_count = 0;
const int context_local_count = 1;
+ const int lexical_context_local_count = 1;
const int context_global_count = 0;
const int strong_mode_free_variable_count = 0;
const bool simple_parameter_list = true;
@@ -254,6 +265,7 @@ Handle<ScopeInfo>
ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
scope_info->SetParameterCount(parameter_count);
scope_info->SetStackLocalCount(stack_local_count);
scope_info->SetContextLocalCount(context_local_count);
+ scope_info->SetLexicalContextLocalCount(lexical_context_local_count);
scope_info->SetContextGlobalCount(context_global_count);
scope_info->SetStrongModeFreeVariableCount(strong_mode_free_variable_count);
@@ -572,6 +584,30 @@ int ScopeInfo::ContextSlotIndex(Handle<ScopeInfo>
scope_info,
}
+int ScopeInfo::LexicalContextSlotIndex(Handle<ScopeInfo> scope_info,
+ Handle<String> name) {
+ DCHECK(name->IsInternalizedString());
+ if (scope_info->length() > 0) {
+ int total_count = scope_info->ContextLocalCount();
+ int lexical_count = scope_info->LexicalContextLocalCount();
+ int non_lexical_count = total_count - lexical_count;
+
+ int start = scope_info->ContextLocalNameEntriesIndex();
+ int end = start + total_count;
+ int lexical_start = start + non_lexical_count;
+
+ for (int i = lexical_start; i < end; ++i) {
+ if (*name == scope_info->get(i)) {
+ int var = i - start;
+ DCHECK(IsLexicalVariableMode(scope_info->ContextLocalMode(var)));
+ return Context::MIN_CONTEXT_SLOTS + var;
+ }
+ }
+ }
+ return -1;
+}
+
+
String* ScopeInfo::ContextSlotName(int slot_index) {
int const var = slot_index - Context::MIN_CONTEXT_SLOTS;
DCHECK_LE(0, var);
Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index
319aca518ed69187dc29cc817c58f9266b2a8700..ce06976c4c9d2369d208d41ccc53a9431f9cba8e
100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -593,7 +593,11 @@ class VarAndOrder {
Variable* var() const { return var_; }
int order() const { return order_; }
static int Compare(const VarAndOrder* a, const VarAndOrder* b) {
- return a->order_ - b->order_;
+ // Sort lexical variables to the end of the list.
+ bool a_is_lexical = IsLexicalVariableMode(a->var()->mode());
+ bool b_is_lexical = IsLexicalVariableMode(b->var()->mode());
+ if (a_is_lexical == b_is_lexical) return a->order_ - b->order_;
+ return a_is_lexical ? 1 : -1;
}
private:
--
--
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