Support scope information and evaluation in optimized frames

src/deoptimizer.h

 // Copyright 2011 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 699 matching lines @@
   }
 
   JSFunction* function_;
   int parameters_count_;
   int expression_count_;
   Object** parameters_;
   Object** expression_stack_;
 
   friend class Deoptimizer;
 };
+
+
+// Scoped version of DeoptimizedFrameInfo.
+class ScopedDeoptimizedFrameInfo {

[Sven Panne, 2011/07/12 13:40:32]

This class looks a bits strange: If the frame passed to the constructor is not
optimized, every single method call would segfault, meaning that the constructed
object is illegal from a semantical point of view. Therefore, it shouldn't be
possible to construct such an instance in the first place. The test should
probably be moved to the caller or, alternatively, a null object pattern should
be used.

[Søren Thygesen Gjesse, 2011/07/12 14:20:36]

That is true, but it was the simplest way to have a scoped class that ensured
that Deoptimizer::DeleteDebuggerInspectableFrame was called. Let me consider to
make it hold the JavaScriptFrame pointer as well.

+ public:
+  ScopedDeoptimizedFrameInfo(JavaScriptFrame* frame,
+                             int inlined_frame_index,
+                             Isolate* isolate)
+      : deoptimized_frame_(NULL), isolate_(isolate) {
+    // Calculate the deoptimized frame.
+    if (frame->is_optimized()) {
+      deoptimized_frame_ = Deoptimizer::DebuggerInspectableFrame(
+          frame, inlined_frame_index, isolate);
+    }
+  }
+
+  ~ScopedDeoptimizedFrameInfo() {
+    // Get rid of the calculated deoptimized frame if any.
+    if (deoptimized_frame_ != NULL) {
+      Deoptimizer::DeleteDebuggerInspectableFrame(deoptimized_frame_,
+                                                  isolate_);
+    }
+  }
+
+  int parameters_count() { return deoptimized_frame_->parameters_count(); }
+  int expression_count() { return deoptimized_frame_->expression_count(); }
+  JSFunction* GetFunction() { return deoptimized_frame_->GetFunction(); }
+  Object* GetParameter(int index) {
+    return deoptimized_frame_->GetParameter(index);
+  }
+  Object* GetExpression(int index) {
+    return deoptimized_frame_->GetExpression(index);
+  }
+
+ private:
+  DeoptimizedFrameInfo* deoptimized_frame_;
+  Isolate* isolate_;
+};
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEOPTIMIZER_H_