[builtins] Introduce a proper BUILTIN frame type.

src/frames.cc

Index: src/frames.cc
diff --git a/src/frames.cc b/src/frames.cc
index 145f50f49ee579e17d5942bc0d28c3d9aeb46b39..4f4704c555276a53082a5465839ef77868425e43 100644
--- a/src/frames.cc
+++ b/src/frames.cc
@@ -451,10 +451,14 @@ StackFrame::Type StackFrame::ComputeType(const StackFrameIteratorBase* iterator,
       switch (code_obj->kind()) {
         case Code::BUILTIN:
           if (marker->IsSmi()) break;
-          // We treat frames for BUILTIN Code objects as OptimizedFrame for now
-          // (all the builtins with JavaScript linkage are actually generated
-          // with TurboFan currently, so this is sound).
-          return OPTIMIZED;
+          if (code_obj->is_turbofanned()) {
+            // TODO(bmeurer): We treat frames for BUILTIN Code objects as
+            // OptimizedFrame for now (all the builtins with JavaScript
+            // linkage are actually generated with TurboFan currently, so
+            // this is sound).
+            return OPTIMIZED;

[Jarin, 2016/04/20 11:47:57]

What would go wrong if you also optimized functions returned BUILTIN type?
(Pointer maps?)

+          }
+          return BUILTIN;
         case Code::FUNCTION:
           return JAVA_SCRIPT;
         case Code::OPTIMIZED_FUNCTION:
@@ -702,6 +706,7 @@ void StandardFrame::IterateCompiledFrame(ObjectVisitor* v) const {
       case JAVA_SCRIPT:
       case OPTIMIZED:
       case INTERPRETED:
+      case BUILTIN:
         // These frame types have a context, but they are actually stored
         // in the place on the stack that one finds the frame type.
         UNREACHABLE();
@@ -1280,11 +1285,6 @@ int ArgumentsAdaptorFrame::GetNumberOfIncomingArguments() const {
   return Smi::cast(GetExpression(0))->value();
 }
 
-
-Address ArgumentsAdaptorFrame::GetCallerStackPointer() const {
-  return fp() + StandardFrameConstants::kCallerSPOffset;
-}
-
 int ArgumentsAdaptorFrame::GetLength(Address fp) {
   const int offset = ArgumentsAdaptorFrameConstants::kLengthOffset;
   return Smi::cast(Memory::Object_at(fp + offset))->value();
@@ -1295,6 +1295,15 @@ Code* ArgumentsAdaptorFrame::unchecked_code() const {
       Builtins::kArgumentsAdaptorTrampoline);
 }
 
+void BuiltinFrame::Print(StringStream* accumulator, PrintMode mode,
+                         int index) const {
+  // TODO(bmeurer)
+}
+
+int BuiltinFrame::GetNumberOfIncomingArguments() const {
+  return Smi::cast(GetExpression(0))->value();
+}
+
 Address InternalFrame::GetCallerStackPointer() const {
   // Internal frames have no arguments. The stack pointer of the
   // caller is at a fixed offset from the frame pointer.