Chain ScopeInfos together

src/ast/scopeinfo.cc

Index: src/ast/scopeinfo.cc
diff --git a/src/ast/scopeinfo.cc b/src/ast/scopeinfo.cc
index a9e824f415bae54881eb5dc84c3787905418756c..f4d6079c0ab9c0531f2485be7503c0d1c38850d1 100644
--- a/src/ast/scopeinfo.cc
+++ b/src/ast/scopeinfo.cc
@@ -71,10 +71,13 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate, Zone* zone,
   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);
@@ -103,7 +106,8 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate, Zone* zone,
               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);
@@ -191,6 +195,14 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate, Zone* zone,
            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() ||
@@ -212,26 +224,28 @@ Handle<ScopeInfo> ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
   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);
@@ -259,6 +273,7 @@ Handle<ScopeInfo> ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
   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);
@@ -362,6 +377,13 @@ bool ScopeInfo::HasFunctionName() {
   }
 }
 
+bool ScopeInfo::HasOuterScopeInfo() {
+  if (length() > 0) {
+    return HasOuterScopeInfoField::decode(Flags());
+  } else {
+    return false;
+  }
+}
 
 bool ScopeInfo::HasHeapAllocatedLocals() {
   if (length() > 0) {
@@ -382,6 +404,10 @@ String* ScopeInfo::FunctionName() {
   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());
@@ -643,6 +669,10 @@ 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,