Store whether a with scope is actually a debug-eval scope in the scope info

This is required to be able to deserialize the scope chain from the
scope info alone.

BUG=v8:5215
R=marja@chromium.org,jgruber@chromium.org

Review-Url: https://codereview.chromium.org/2331323006
Cr-Commit-Position: refs/heads/master@{#39412}

src/ast/scopeinfo.cc

@@ -155,18 +155,20 @@ Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate, Zone* zone, Scope* scope,
   }
 
   // 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) |
-              AsmModuleField::encode(asm_module) |
-              AsmFunctionField::encode(asm_function) |
-              HasSimpleParametersField::encode(has_simple_parameters) |
-              FunctionKindField::encode(function_kind) |
-              HasOuterScopeInfoField::encode(has_outer_scope_info);
+  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) |
+      AsmModuleField::encode(asm_module) |
+      AsmFunctionField::encode(asm_function) |
+      HasSimpleParametersField::encode(has_simple_parameters) |
+      FunctionKindField::encode(function_kind) |
+      HasOuterScopeInfoField::encode(has_outer_scope_info) |
+      IsDebugEvaluateScopeField::encode(scope->is_debug_evaluate_scope());
   scope_info->SetFlags(flags);
 
   scope_info->SetParameterCount(parameter_count);
@@ -302,7 +304,8 @@ Handle<ScopeInfo> ScopeInfo::CreateForWithScope(
       FunctionVariableField::encode(NONE) | AsmModuleField::encode(false) |
       AsmFunctionField::encode(false) | HasSimpleParametersField::encode(true) |
       FunctionKindField::encode(kNormalFunction) |
-      HasOuterScopeInfoField::encode(has_outer_scope_info);
+      HasOuterScopeInfoField::encode(has_outer_scope_info) |
+      IsDebugEvaluateScopeField::encode(false);
   scope_info->SetFlags(flags);
 
   scope_info->SetParameterCount(0);
@@ -355,7 +358,8 @@ Handle<ScopeInfo> ScopeInfo::CreateGlobalThisBinding(Isolate* isolate) {
       AsmModuleField::encode(false) | AsmFunctionField::encode(false) |
       HasSimpleParametersField::encode(has_simple_parameters) |
       FunctionKindField::encode(FunctionKind::kNormalFunction) |
-      HasOuterScopeInfoField::encode(has_outer_scope_info);
+      HasOuterScopeInfoField::encode(has_outer_scope_info) |
+      IsDebugEvaluateScopeField::encode(false);
   scope_info->SetFlags(flags);
   scope_info->SetParameterCount(parameter_count);
   scope_info->SetStackLocalCount(stack_local_count);
@@ -491,6 +495,23 @@ bool ScopeInfo::HasOuterScopeInfo() {
   }
 }
 
+bool ScopeInfo::IsDebugEvaluateScope() {
+  if (length() > 0) {
+    return IsDebugEvaluateScopeField::decode(Flags());
+  } else {
+    return false;
+  }
+}
+
+void ScopeInfo::SetIsDebugEvaluateScope() {
+  if (length() > 0) {
+    DCHECK_EQ(scope_type(), WITH_SCOPE);
+    SetFlags(Flags() | IsDebugEvaluateScopeField::encode(true));
+  } else {
+    UNREACHABLE();
+  }
+}
+
 bool ScopeInfo::HasHeapAllocatedLocals() {
   if (length() > 0) {
     return ContextLocalCount() > 0;

src/ast/scopes.h

@@ -409,6 +409,7 @@ class Scope: public ZoneObject {
   // Retrieve `IsSimpleParameterList` of current or outer function.
   bool HasSimpleParameters();
   void set_is_debug_evaluate_scope() { is_debug_evaluate_scope_ = true; }
+  bool is_debug_evaluate_scope() const { return is_debug_evaluate_scope_; }
 
  protected:
   explicit Scope(Zone* zone);

src/debug/debug-evaluate.cc

@@ -209,14 +209,13 @@ DebugEvaluate::ContextBuilder::ContextBuilder(Isolate* isolate,
   }
 
   for (int i = context_chain_.length() - 1; i >= 0; i--) {
+    Handle<ScopeInfo> scope_info(ScopeInfo::CreateForWithScope(
+        isolate, evaluation_context_->IsNativeContext()
+                     ? Handle<ScopeInfo>::null()
+                     : Handle<ScopeInfo>(evaluation_context_->scope_info())));
+    scope_info->SetIsDebugEvaluateScope();
     evaluation_context_ = factory->NewDebugEvaluateContext(
-        evaluation_context_,
-        ScopeInfo::CreateForWithScope(
-            isolate,
-            evaluation_context_->IsNativeContext()
-                ? Handle<ScopeInfo>::null()
-                : Handle<ScopeInfo>(evaluation_context_->scope_info())),
-        context_chain_[i].materialized_object,
+        evaluation_context_, scope_info, context_chain_[i].materialized_object,
         context_chain_[i].wrapped_context, context_chain_[i].whitelist);
   }
 }

src/factory.cc

@@ -844,6 +844,7 @@ Handle<Context> Factory::NewDebugEvaluateContext(Handle<Context> previous,
                                                  Handle<Context> wrapped,
                                                  Handle<StringSet> whitelist) {
   STATIC_ASSERT(Context::WHITE_LIST_INDEX == Context::MIN_CONTEXT_SLOTS + 1);
+  DCHECK(scope_info->IsDebugEvaluateScope());
   Handle<ContextExtension> context_extension = NewContextExtension(
       scope_info, extension.is_null() ? Handle<Object>::cast(undefined_value())
                                       : Handle<Object>::cast(extension));

src/objects.h

@@ -4394,6 +4394,13 @@ class ScopeInfo : public FixedArray {
   // Returns true if this ScopeInfo is linked to a outer ScopeInfo.
   bool HasOuterScopeInfo();
 
+  // Returns true if this ScopeInfo was created for a debug-evaluate scope.
+  bool IsDebugEvaluateScope();
+
+  // Can be used to mark a ScopeInfo that looks like a with-scope as actually
+  // being a debug-evaluate scope.
+  void SetIsDebugEvaluateScope();
+
   // Return the outer ScopeInfo if present.
   ScopeInfo* OuterScopeInfo();
 
@@ -4525,6 +4532,8 @@ class ScopeInfo : public FixedArray {
       : public BitField<FunctionKind, HasSimpleParametersField::kNext, 9> {};
   class HasOuterScopeInfoField
       : public BitField<bool, FunctionKindField::kNext, 1> {};
+  class IsDebugEvaluateScopeField
+      : public BitField<bool, HasOuterScopeInfoField::kNext, 1> {};
 
   // Properties of variables.
   class VariableModeField : public BitField<VariableMode, 0, 3> {};