Initial implementation of on-stack replacement (OSR).

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
diff --git a/runtime/vm/assembler_x64.h b/runtime/vm/assembler_x64.h
index c2135060778ec50dddb644861eaab0fb9916488b..894a841c361b6a21503686f047a6f839beee2128 100644
--- a/runtime/vm/assembler_x64.h
+++ b/runtime/vm/assembler_x64.h
@@ -735,6 +735,11 @@ class Assembler : public ValueObject {
   //   .....
   void EnterDartFrame(intptr_t frame_size);
 
+  // Set up a Dart frame for a function compiled for on-stack replacement.
+  // The frame layout is a normal dart frame, but the frame is partially set

[srdjan, 2013/06/11 17:12:02]

s/dart/Dart/

[Kevin Millikin (Google), 2013/06/14 10:10:42]

Done.

+  // up on entry (it is the frame of the unoptimized code).
+  void EnterOsrFrame(intptr_t extra_size);
+
   // Set up a stub frame so that the stack traversal code can easily identify
   // a stub frame.
   // The stub frame layout is as follows: