From 3fcbb8f1d0c03022874b3b7bcf4ef364c5c3d661 Mon Sep 17 00:00:00 2001
From: "yangguo@chromium.org"
 <yangguo@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Wed, 23 Jan 2013 14:01:11 +0000
Subject: [PATCH] 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 | 26 ++++++++------------------
 src/mips/lithium-mips.h          |  6 ++++--
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 33a32e7a50..054ca15ddd 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/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);
+                     maps->at(i),
+                     ALLOW_ELEMENT_TRANSITION_MAPS,
+                     instr->environment());
   }
-
-  // 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());
 }
 
 
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index a9116ef8db..fb24632baf 100644
--- a/src/mips/lithium-mips.h
+++ b/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(); }
 };