Chain ScopeInfos together

src/ast/scopeinfo.cc

 // Copyright 2011 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 <stdlib.h>
 
 #include "src/ast/context-slot-cache.h"
 #include "src/ast/scopes.h"
 #include "src/bootstrapper.h"
 
@@ skipping 53 matching lines @@
     function_variable_mode = var->mode();
   } else {
     function_name_info = NONE;
     function_variable_mode = VAR;
   }
   DCHECK(context_global_count == 0 || scope->scope_type() == SCRIPT_SCOPE);
 
   const bool has_function_name = function_name_info != NONE;
   const bool has_receiver = receiver_info == STACK || receiver_info == CONTEXT;
   const int parameter_count = scope->num_parameters();
+  const bool has_outer_scope_info =
+      scope->GetOuterScopeWithContext() != nullptr;
   const int length = kVariablePartIndex + parameter_count +
                      (1 + stack_local_count) + 2 * context_local_count +
-                     2 * context_global_count +
-                     (has_receiver ? 1 : 0) + (has_function_name ? 2 : 0);
+                     2 * context_global_count + (has_receiver ? 1 : 0) +
+                     (has_function_name ? 2 : 0) +
+                     (has_outer_scope_info ? 1 : 0);
 
   Factory* factory = isolate->factory();
   Handle<ScopeInfo> scope_info = factory->NewScopeInfo(length);
 
   bool has_simple_parameters = false;
   bool asm_module = false;
   bool asm_function = false;
   FunctionKind function_kind = kNormalFunction;
   if (scope->is_function_scope()) {
     DeclarationScope* function_scope = scope->AsDeclarationScope();
     has_simple_parameters = function_scope->has_simple_parameters();
     asm_module = function_scope->asm_module();
     asm_function = function_scope->asm_function();
     function_kind = function_scope->function_kind();
   }
 
   // Encode the flags.
   int flags = ScopeTypeField::encode(scope->scope_type()) |
               CallsEvalField::encode(scope->calls_eval()) |
               LanguageModeField::encode(scope->language_mode()) |
               DeclarationScopeField::encode(scope->is_declaration_scope()) |
               ReceiverVariableField::encode(receiver_info) |
               HasNewTargetField::encode(has_new_target) |
               FunctionVariableField::encode(function_name_info) |
               FunctionVariableMode::encode(function_variable_mode) |
               AsmModuleField::encode(asm_module) |
               AsmFunctionField::encode(asm_function) |
               HasSimpleParametersField::encode(has_simple_parameters) |
-              FunctionKindField::encode(function_kind);
+              FunctionKindField::encode(function_kind) |
+              HasOuterScopeInfoField::encode(has_outer_scope_info);
   scope_info->SetFlags(flags);
   scope_info->SetParameterCount(parameter_count);
   scope_info->SetStackLocalCount(stack_local_count);
   scope_info->SetContextLocalCount(context_local_count);
   scope_info->SetContextGlobalCount(context_global_count);
 
   int index = kVariablePartIndex;
   // Add parameters.
   DCHECK_EQ(index, scope_info->ParameterEntriesIndex());
   if (scope->is_declaration_scope()) {
@@ skipping 67 matching lines @@
   DCHECK(index == scope_info->FunctionNameEntryIndex());
   if (has_function_name) {
     int var_index = scope->AsDeclarationScope()->function_var()->index();
     scope_info->set(index++,
                     *scope->AsDeclarationScope()->function_var()->name());
     scope_info->set(index++, Smi::FromInt(var_index));
     DCHECK(function_name_info != CONTEXT ||
            var_index == scope_info->ContextLength() - 1);
   }
 
+  // If present, add the outer scope info.
+  DCHECK(index == scope_info->OuterScopeInfoEntryIndex());
+  if (has_outer_scope_info) {
+    Handle<ScopeInfo> outer_scope_info =
+        scope->GetOuterScopeWithContext()->GetScopeInfo(isolate);
+    scope_info->set(index++, *outer_scope_info);
+  }
+
   DCHECK(index == scope_info->length());
   DCHECK(scope->num_parameters() == scope_info->ParameterCount());
   DCHECK(scope->num_heap_slots() == scope_info->ContextLength() ||
          (scope->num_heap_slots() == kVariablePartIndex &&
           scope_info->ContextLength() == 0));
   return scope_info;
 }
 
 
 Handle<ScopeInfo> ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
   DCHECK(isolate->bootstrapper()->IsActive());
 
   const int stack_local_count = 0;
   const int context_local_count = 1;
   const int context_global_count = 0;
   const bool has_simple_parameters = true;
   const VariableAllocationInfo receiver_info = CONTEXT;
   const VariableAllocationInfo function_name_info = NONE;
   const VariableMode function_variable_mode = VAR;
   const bool has_function_name = false;
   const bool has_receiver = true;
+  const bool has_outer_scope_info = false;
   const int parameter_count = 0;
   const int length = kVariablePartIndex + parameter_count +
                      (1 + stack_local_count) + 2 * context_local_count +
-                     2 * context_global_count +
-                     (has_receiver ? 1 : 0) + (has_function_name ? 2 : 0);
+                     2 * context_global_count + (has_receiver ? 1 : 0) +
+                     (has_function_name ? 2 : 0) +
+                     (has_outer_scope_info ? 1 : 0);
 
   Factory* factory = isolate->factory();
   Handle<ScopeInfo> scope_info = factory->NewScopeInfo(length);
 
   // Encode the flags.
-  int flags = ScopeTypeField::encode(SCRIPT_SCOPE) |
-              CallsEvalField::encode(false) |
-              LanguageModeField::encode(SLOPPY) |
-              DeclarationScopeField::encode(true) |
-              ReceiverVariableField::encode(receiver_info) |
-              FunctionVariableField::encode(function_name_info) |
-              FunctionVariableMode::encode(function_variable_mode) |
-              AsmModuleField::encode(false) | AsmFunctionField::encode(false) |
-              HasSimpleParametersField::encode(has_simple_parameters) |
-              FunctionKindField::encode(FunctionKind::kNormalFunction);
+  int flags =
+      ScopeTypeField::encode(SCRIPT_SCOPE) | CallsEvalField::encode(false) |
+      LanguageModeField::encode(SLOPPY) | DeclarationScopeField::encode(true) |
+      ReceiverVariableField::encode(receiver_info) |
+      FunctionVariableField::encode(function_name_info) |
+      FunctionVariableMode::encode(function_variable_mode) |
+      AsmModuleField::encode(false) | AsmFunctionField::encode(false) |
+      HasSimpleParametersField::encode(has_simple_parameters) |
+      FunctionKindField::encode(FunctionKind::kNormalFunction) |
+      HasOuterScopeInfoField::encode(has_outer_scope_info);
   scope_info->SetFlags(flags);
   scope_info->SetParameterCount(parameter_count);
   scope_info->SetStackLocalCount(stack_local_count);
   scope_info->SetContextLocalCount(context_local_count);
   scope_info->SetContextGlobalCount(context_global_count);
 
   int index = kVariablePartIndex;
   const int first_slot_index = 0;
   DCHECK(index == scope_info->StackLocalFirstSlotIndex());
   scope_info->set(index++, Smi::FromInt(first_slot_index));
   DCHECK(index == scope_info->StackLocalEntriesIndex());
 
   // Here we add info for context-allocated "this".
   DCHECK(index == scope_info->ContextLocalNameEntriesIndex());
   scope_info->set(index++, *isolate->factory()->this_string());
   DCHECK(index == scope_info->ContextLocalInfoEntriesIndex());
   const uint32_t value = VariableModeField::encode(CONST) |
                          InitFlagField::encode(kCreatedInitialized) |
                          MaybeAssignedFlagField::encode(kNotAssigned);
   scope_info->set(index++, Smi::FromInt(value));
 
   // And here we record that this scopeinfo binds a receiver.
   DCHECK(index == scope_info->ReceiverEntryIndex());
   const int receiver_index = Context::MIN_CONTEXT_SLOTS + 0;
   scope_info->set(index++, Smi::FromInt(receiver_index));
 
   DCHECK(index == scope_info->FunctionNameEntryIndex());
+  DCHECK(index == scope_info->OuterScopeInfoEntryIndex());
 
   DCHECK_EQ(index, scope_info->length());
   DCHECK_EQ(scope_info->ParameterCount(), 0);
   DCHECK_EQ(scope_info->ContextLength(), Context::MIN_CONTEXT_SLOTS + 1);
 
   return scope_info;
 }
 
 
 ScopeInfo* ScopeInfo::Empty(Isolate* isolate) {
@@ skipping 83 matching lines @@
 
 
 bool ScopeInfo::HasFunctionName() {
   if (length() > 0) {
     return NONE != FunctionVariableField::decode(Flags());
   } else {
     return false;
   }
 }
 
+bool ScopeInfo::HasOuterScopeInfo() {
+  if (length() > 0) {
+    return HasOuterScopeInfoField::decode(Flags());
+  } else {
+    return false;
+  }
+}
 
 bool ScopeInfo::HasHeapAllocatedLocals() {
   if (length() > 0) {
     return ContextLocalCount() > 0;
   } else {
     return false;
   }
 }
 
 
 bool ScopeInfo::HasContext() {
   return ContextLength() > 0;
 }
 
 
 String* ScopeInfo::FunctionName() {
   DCHECK(HasFunctionName());
   return String::cast(get(FunctionNameEntryIndex()));
 }
 
+ScopeInfo* ScopeInfo::OuterScopeInfo() {
+  DCHECK(HasOuterScopeInfo());
+  return ScopeInfo::cast(get(OuterScopeInfoEntryIndex()));
+}
 
 String* ScopeInfo::ParameterName(int var) {
   DCHECK(0 <= var && var < ParameterCount());
   int info_index = ParameterEntriesIndex() + var;
   return String::cast(get(info_index));
 }
 
 
 String* ScopeInfo::LocalName(int var) {
   DCHECK(0 <= var && var < LocalCount());
@@ skipping 241 matching lines @@
 
 int ScopeInfo::ReceiverEntryIndex() {
   return ContextGlobalInfoEntriesIndex() + ContextGlobalCount();
 }
 
 
 int ScopeInfo::FunctionNameEntryIndex() {
   return ReceiverEntryIndex() + (HasAllocatedReceiver() ? 1 : 0);
 }
 
+int ScopeInfo::OuterScopeInfoEntryIndex() {
+  return FunctionNameEntryIndex() + (HasFunctionName() ? 2 : 0);
+}
+
 #ifdef DEBUG
 
 static void PrintList(const char* list_name,
                       int nof_internal_slots,
                       int start,
                       int end,
                       ScopeInfo* scope_info) {
   if (start < end) {
     PrintF("\n  // %s\n", list_name);
     if (nof_internal_slots > 0) {
@@ skipping 27 matching lines @@
               ContextLocalNameEntriesIndex() + ContextLocalCount(), this);
   }
 
   PrintF("}\n");
 }
 #endif  // DEBUG
 
 
 }  // namespace internal
 }  // namespace v8