VM: New calling convention for generated code.

runtime/vm/stack_frame.cc

Index: runtime/vm/stack_frame.cc
diff --git a/runtime/vm/stack_frame.cc b/runtime/vm/stack_frame.cc
index a8ceedf53a7d678b0a839b688e3a5719b05925a7..7e687e49645a07b2ad537d98ee89ca8ba01901a9 100644
--- a/runtime/vm/stack_frame.cc
+++ b/runtime/vm/stack_frame.cc
@@ -22,9 +22,7 @@ namespace dart {
 
 bool StackFrame::IsStubFrame() const {
   ASSERT(!(IsEntryFrame() || IsExitFrame()));
-  uword saved_pc =
-      *(reinterpret_cast<uword*>(fp() + (kPcMarkerSlotFromFp * kWordSize)));
-  return (saved_pc == 0);
+  return (LookupDartCode() == Code::null());
 }
 
 
@@ -175,8 +173,11 @@ RawCode* StackFrame::LookupDartCode() const {
   // that the code is called while a GC is in progress, that is ok.
   NoSafepointScope no_safepoint;
   RawCode* code = GetCodeObject();
-  ASSERT(code == Code::null() || code->ptr()->owner_ != Function::null());
-  return code;
+  if ((code != Code::null()) &&
+      (code->ptr()->owner_->GetClassId() == kFunctionCid)) {
+    return code;
+  }
+  return Code::null();
 }
 
 
@@ -188,12 +189,12 @@ RawCode* StackFrame::GetCodeObject() const {
   const uword pc_marker =
       *(reinterpret_cast<uword*>(fp() + (kPcMarkerSlotFromFp * kWordSize)));
   if (pc_marker != 0) {
-    const uword entry_point =
-        (pc_marker - Assembler::EntryPointToPcMarkerOffset());
-    RawInstructions* instr = Instructions::FromEntryPoint(entry_point);
-    if (instr != Instructions::null()) {
-      return instr->ptr()->code_;
-    }
+#if defined(TARGET_ARCH_X64)
+    ASSERT(reinterpret_cast<RawObject*>(pc_marker)->GetClassId() == kCodeCid);
+    return reinterpret_cast<RawCode*>(pc_marker);
+#else
+    UNIMPLEMENTED();
+#endif
   }
   return Code::null();
 }