Revert "VM: New calling convention for generated code."

runtime/vm/stack_frame_ia32.h

Index: runtime/vm/stack_frame_ia32.h
diff --git a/runtime/vm/stack_frame_ia32.h b/runtime/vm/stack_frame_ia32.h
index 29d0c43c4f30d9b1d8de5a03d4bd2911d869f6ba..f1a379b52e2ca1cbf07ca41c624647a1e3a37643 100644
--- a/runtime/vm/stack_frame_ia32.h
+++ b/runtime/vm/stack_frame_ia32.h
@@ -16,7 +16,7 @@ Callee frame   | ...                |
                +--------------------+
 Current frame  | ...               T| <- ESP of current frame
                | first local       T|
-               | code object       T|    (current frame's code object)
+               | PC marker          |    (current frame's code entry + offset)
                | caller's EBP       | <- EBP of current frame
                | caller's ret addr  |    (PC of caller frame)
                +--------------------+
@@ -29,7 +29,7 @@ Caller frame   | last parameter     | <- ESP of caller frame
 static const int kDartFrameFixedSize = 3;  // PC marker, EBP, PC.
 static const int kSavedPcSlotFromSp = -1;
 
-static const int kFirstObjectSlotFromFp = -1;  // Used by GC to traverse stack.
+static const int kFirstObjectSlotFromFp = -2;  // Used by GC to traverse stack.
 
 static const int kFirstLocalSlotFromFp = -2;
 static const int kPcMarkerSlotFromFp = -1;