MIPS: Make HCheckPrototypeMaps compatible with parallel recompilation.

Port r13454 (2c0dd0ff)

Original commit message:
HCheckPrototypeMaps currently records the prototype and the holder of the
prototype chain (both ends of the chain) and assumes that the chain elements
and their maps did not change in during the entirety of Crankshaft. The actual
traversal of the prototype chain happens in Lithium at code generation.
With parallel compilation, this assumption is not longer correct.

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/12036030
Patch from Akos Palfi <palfia@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13476 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -5005,29 +5005,19 @@ void LCodeGen::DoCheckPrototypeMaps(LCheckPrototypeMaps* instr) {
   Register prototype_reg = ToRegister(instr->temp());
   Register map_reg = ToRegister(instr->temp2());
 
-  Handle<JSObject> holder = instr->holder();
-  Handle<JSObject> current_prototype = instr->prototype();
+  ZoneList<Handle<JSObject> >* prototypes = instr->prototypes();
+  ZoneList<Handle<Map> >* maps = instr->maps();
 
-  // Load prototype object.
-  __ LoadHeapObject(prototype_reg, current_prototype);
+  ASSERT(prototypes->length() == maps->length());
 
-  // Check prototype maps up to the holder.
-  while (!current_prototype.is_identical_to(holder)) {
+  for (int i = 0; i < prototypes->length(); i++) {
+    __ LoadHeapObject(prototype_reg, prototypes->at(i));
     __ lw(map_reg, FieldMemOperand(prototype_reg, HeapObject::kMapOffset));
     DoCheckMapCommon(map_reg,
-                     Handle<Map>(current_prototype->map()),
-                     ALLOW_ELEMENT_TRANSITION_MAPS, instr->environment());
-    current_prototype =
-        Handle<JSObject>(JSObject::cast(current_prototype->GetPrototype()));
-    // Load next prototype object.
-    __ LoadHeapObject(prototype_reg, current_prototype);
-  }
-
-  // Check the holder map.
-  __ lw(map_reg, FieldMemOperand(prototype_reg, HeapObject::kMapOffset));
-  DoCheckMapCommon(map_reg,
-                   Handle<Map>(current_prototype->map()),
-                   ALLOW_ELEMENT_TRANSITION_MAPS, instr->environment());
+                     maps->at(i),
+                     ALLOW_ELEMENT_TRANSITION_MAPS,
+                     instr->environment());
+  }
 }
 
 

src/mips/lithium-mips.h

@@ -2130,8 +2130,10 @@ class LCheckPrototypeMaps: public LTemplateInstruction<1, 0, 2> {
   DECLARE_CONCRETE_INSTRUCTION(CheckPrototypeMaps, "check-prototype-maps")
   DECLARE_HYDROGEN_ACCESSOR(CheckPrototypeMaps)
 
-  Handle<JSObject> prototype() const { return hydrogen()->prototype(); }
-  Handle<JSObject> holder() const { return hydrogen()->holder(); }
+  ZoneList<Handle<JSObject> >* prototypes() const {
+    return hydrogen()->prototypes();
+  }
+  ZoneList<Handle<Map> >* maps() const { return hydrogen()->maps(); }
 };