X64 platform: Add more register allocator functions.

src/x64/virtual-frame-x64.cc

 // Copyright 2009 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:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 81 matching lines @@
 
 void VirtualFrame::Exit() {
   Comment cmnt(masm(), "[ Exit JS frame");
   // Record the location of the JS exit code for patching when setting
   // break point.
   __ RecordJSReturn();
 
   // Avoid using the leave instruction here, because it is too
   // short. We need the return sequence to be a least the size of a
   // call instruction to support patching the exit code in the
   // debugger. See VisitReturnStatement for the full return sequence.

[Kevin Millikin (Chromium), 2009/06/16 08:27:03]

The return sequence is not in VisitReturnStatement.  It's in
GenerateReturnSequence.

+  // TODO(X64): A patched call will be very long now.  Make sure we
+  // have enough room.
   __ movq(rsp, rbp);
   stack_pointer_ = frame_pointer();
   for (int i = element_count() - 1; i > stack_pointer_; i--) {
     FrameElement last = elements_.RemoveLast();
     if (last.is_register()) {
       Unuse(last.reg());
     }
   }
 
   EmitPop(rbp);
@@ skipping 72 matching lines @@
 }
 
 void VirtualFrame::SyncRange(int a, int b) {
   UNIMPLEMENTED();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal