VM: New calling convention for generated code.

runtime/vm/stack_frame.h

Index: runtime/vm/stack_frame.h
diff --git a/runtime/vm/stack_frame.h b/runtime/vm/stack_frame.h
index 94ba9d31837e3fdcd98ae4b278df180be3530ec7..b2bffd74f497e3cf8c662894bb5318cb306581be 100644
--- a/runtime/vm/stack_frame.h
+++ b/runtime/vm/stack_frame.h
@@ -50,7 +50,11 @@ class StackFrame : public ValueObject {
   }
 
   void set_pc(uword value) {
-    *reinterpret_cast<uword*>(sp_ + (kSavedPcSlotFromSp * kWordSize)) = value;
+    *reinterpret_cast<uword*>(sp() + (kSavedPcSlotFromSp * kWordSize)) = value;
+  }
+
+  void set_pc_marker(uword value) {

[koda, 2015/09/11 13:22:05]

Since this slot is traversed by GC, shouldn't this interface take a RawObject*
(or RawCode*)?

[Florian Schneider, 2015/09/11 14:30:23]

Done. (and yes, I'm not done with renaming pc-marker yet... for now everything
named pc-marker just contains a RawCode object)

+    *reinterpret_cast<uword*>(fp() + (kPcMarkerSlotFromFp * kWordSize)) = value;
   }
 
   // Visit objects in the frame.