Reimplement stack manipulations for LiveEdit

src/ia32/debug-ia32.cc

 // Copyright 2010 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 236 matching lines @@
   // object pointers.
   Generate_DebugBreakCallHelper(masm, 0, true);
 }
 
 
 void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
   masm->ret(0);
 }
 
 
-// FrameDropper is a code replacement for a JavaScript frame with possibly
-// several frames above.
-// There is no calling conventions here, because it never actually gets called,
-// it only gets returned to.
-// Frame structure (conforms InternalFrame structure):
-//   -- JSFunction
-//   -- code
-//   -- SMI maker
-//   -- context
-//   -- frame base
-void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
-  // We do not know our frame height, but set esp based on ebp.
-  __ lea(esp, Operand(ebp, -4 * kPointerSize));
+// See documentation in debug.h.
+void Debug::GenerateRestarterPatchLiveEdit(MacroAssembler* masm) {
+#ifdef DEBUG
+  int offset1 = masm->pc_offset();
+  __ nop();
+  int offset2 = masm->pc_offset();
+  ASSERT_EQ(offset2 - offset1, kFrameRestarterEntryOffset);
+#else
+  __ nop();
+#endif
 
+  ExternalReference restarted_frame_id =
+      ExternalReference(Debug_Address::RestartedFrameFp());
+
+  // Reset restarted_frame_id variable. It means that frame has
+  // actually restarted and has become a regular frame.
+  __ mov(Operand::StaticVariable(restarted_frame_id), Immediate(0));
+
+  // Whatever the height the frame was, reset the stack pointer
+  // according to the base pointer.
+  __ lea(esp, Operand(ebp, -2 * kPointerSize));
+
+  // Read back registers value.
   __ pop(edi);  // function
-
-  // Skip code self-reference and marker.
-  __ add(Operand(esp), Immediate(2 * kPointerSize));
-
   __ pop(esi);  // Context.
   __ pop(ebp);
 
   // Get function code.
   __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
   __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
   __ lea(edx, FieldOperand(edx, Code::kHeaderSize));
 
   // Re-run JSFunction, edi is function, esi is context.
   __ jmp(Operand(edx));
 }
 
 #undef __
 
 
-void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
-                                   Handle<Code> code) {
-  ASSERT(bottom_js_frame->is_java_script());
+const int Debug::kFrameRestarterEntryOffset = 1;
+const int Debug::kRestartedFrameHeight = 3;
 
-  Address fp = bottom_js_frame->fp();
-  Memory::Object_at(fp - 4 * kPointerSize) =
-      Memory::Object_at(fp - 2 * kPointerSize);  // Move edi (function).
-
-  Memory::Object_at(fp - 3 * kPointerSize) = *code;
-  Memory::Object_at(fp - 2 * kPointerSize) = Smi::FromInt(StackFrame::INTERNAL);
-}
-const int Debug::kFrameDropperFrameSize = 5;
 
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32