Improve algorithm for detaching and attaching a virtual frame to the code...

src/x64/virtual-frame-x64.h

 // 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 112 matching lines @@
 
   // Make this virtual frame have a state identical to an expected virtual
   // frame.  As a side effect, code may be emitted to make this frame match
   // the expected one.
   void MergeTo(VirtualFrame* expected);
 
   // Detach a frame from its code generator, perhaps temporarily.  This
   // tells the register allocator that it is free to use frame-internal
   // registers.  Used when the code generator's frame is switched from this
   // one to NULL by an unconditional jump.
-  void DetachFromCodeGenerator();
-
+  void DetachFromCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Unuse(temp);
+      }
+    }
+  }
   // (Re)attach a frame to its code generator.  This informs the register
   // allocator that the frame-internal register references are active again.
   // Used when a code generator's frame is switched from NULL to this one by
   // binding a label.
-  void AttachToCodeGenerator();
+  void AttachToCodeGenerator() {
+    RegisterAllocator* cgen_allocator = cgen_->allocator();
+    for (int i = 0; i < kNumRegisters; i++) {
+      if (is_used(i)) {
+        Register temp = { i };
+        cgen_allocator->Use(temp);
+      }
+    }
+  }
 
   // Emit code for the physical JS entry and exit frame sequences.  After
   // calling Enter, the virtual frame is ready for use; and after calling
   // Exit it should not be used.  Note that Enter does not allocate space in
   // the physical frame for storing frame-allocated locals.
   void Enter();
   void Exit();
 
   // Prepare for returning from the frame by spilling locals.  This
   // avoids generating unnecessary merge code when jumping to the
@@ skipping 334 matching lines @@
   Result RawCallCodeObject(Handle<Code> code, RelocInfo::Mode rmode);
 
   bool Equals(VirtualFrame* other);
 
   friend class JumpTarget;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_VIRTUAL_FRAME_X64_H_