diff --git a/src/macro-assembler.h b/src/macro-assembler.h
index 30838bd..11e2217 100644
--- a/src/macro-assembler.h
+++ b/src/macro-assembler.h
@@ -1,4 +1,4 @@
-// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -36,27 +36,6 @@
 };
 
 
-enum CodeLocation {
-  IN_JAVASCRIPT,
-  IN_JS_ENTRY,
-  IN_C_ENTRY
-};
-
-
-enum HandlerType {
-  TRY_CATCH_HANDLER,
-  TRY_FINALLY_HANDLER,
-  JS_ENTRY_HANDLER
-};
-
-
-// Types of uncatchable exceptions.
-enum UncatchableExceptionType {
-  OUT_OF_MEMORY,
-  TERMINATION
-};
-
-
 // Invalid depth in prototype chain.
 const int kInvalidProtoDepth = -1;
 
@@ -93,6 +72,63 @@
 namespace v8 {
 namespace internal {
 
+class FrameScope {
+ public:
+  explicit FrameScope(MacroAssembler* masm, StackFrame::Type type)
+      : masm_(masm), type_(type), old_has_frame_(masm->has_frame()) {
+    masm->set_has_frame(true);
+    if (type != StackFrame::MANUAL && type_ != StackFrame::NONE) {
+      masm->EnterFrame(type);
+    }
+  }
+
+  ~FrameScope() {
+    if (type_ != StackFrame::MANUAL && type_ != StackFrame::NONE) {
+      masm_->LeaveFrame(type_);
+    }
+    masm_->set_has_frame(old_has_frame_);
+  }
+
+  // Normally we generate the leave-frame code when this object goes
+  // out of scope.  Sometimes we may need to generate the code somewhere else
+  // in addition.  Calling this will achieve that, but the object stays in
+  // scope, the MacroAssembler is still marked as being in a frame scope, and
+  // the code will be generated again when it goes out of scope.
+  void GenerateLeaveFrame() {
+    masm_->LeaveFrame(type_);
+  }
+
+ private:
+  MacroAssembler* masm_;
+  StackFrame::Type type_;
+  bool old_has_frame_;
+};
+
+
+class AllowExternalCallThatCantCauseGC: public FrameScope {
+ public:
+  explicit AllowExternalCallThatCantCauseGC(MacroAssembler* masm)
+      : FrameScope(masm, StackFrame::NONE) { }
+};
+
+
+class NoCurrentFrameScope {
+ public:
+  explicit NoCurrentFrameScope(MacroAssembler* masm)
+      : masm_(masm), saved_(masm->has_frame()) {
+    masm->set_has_frame(false);
+  }
+
+  ~NoCurrentFrameScope() {
+    masm_->set_has_frame(saved_);
+  }
+
+ private:
+  MacroAssembler* masm_;
+  bool saved_;
+};
+
+
 // Support for "structured" code comments.
 #ifdef DEBUG