Make HCheckPrototypeMaps compatible with parallel recompilation.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2405 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(CheckNonSmi)
 
  protected:
   virtual bool DataEquals(HValue* other) { return true; }
 };
 
 
 class HCheckPrototypeMaps: public HTemplateInstruction<0> {
  public:
-  HCheckPrototypeMaps(Handle<JSObject> prototype, Handle<JSObject> holder)
-      : prototype_(prototype), holder_(holder) {
+  HCheckPrototypeMaps(Handle<JSObject> prototype,
+                      Handle<JSObject> holder,
+                      Zone* zone) : prototypes_(2, zone), maps_(2, zone) {
     SetFlag(kUseGVN);
     SetGVNFlag(kDependsOnMaps);
+    // Keep a list of all objects on the prototype chain up to the holder
+    // and the expected maps.
+    while (true) {
+      prototypes_.Add(prototype, zone);
+      maps_.Add(Handle<Map>(prototype->map()), zone);
+      if (prototype.is_identical_to(holder)) break;
+      prototype = Handle<JSObject>(JSObject::cast(prototype->GetPrototype()));
+    }
   }
 
-  Handle<JSObject> prototype() const { return prototype_; }
-  Handle<JSObject> holder() const { return holder_; }
+  ZoneList< Handle<JSObject> >* prototypes() { return &prototypes_; }
+

[Michael Starzinger, 2013/01/15 11:12:37]

Drop the empty newline.

+  ZoneList< Handle<Map> >* maps() { return &maps_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckPrototypeMaps)
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::None();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   virtual intptr_t Hashcode() {
     ASSERT_ALLOCATION_DISABLED;
-    intptr_t hash = reinterpret_cast<intptr_t>(*prototype());
-    hash = 17 * hash + reinterpret_cast<intptr_t>(*holder());
+    intptr_t hash = 0;
+    for (int i = 0; i < prototypes_.length(); i++) {
+      hash = 17 * hash + reinterpret_cast<intptr_t>(*prototypes_[i]);
+      hash = 17 * hash + reinterpret_cast<intptr_t>(*maps_[i]);
+    }
     return hash;
   }
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HCheckPrototypeMaps* b = HCheckPrototypeMaps::cast(other);
-    return prototype_.is_identical_to(b->prototype()) &&
-        holder_.is_identical_to(b->holder());
+    if (prototypes_.length() != b->prototypes()->length()) return false;
+    for (int i = 0; i < prototypes_.length(); i++) {
+      if (!prototypes_[i].is_identical_to(b->prototypes()->at(i))) return false;
+      if (!maps_[i].is_identical_to(b->maps()->at(i))) return false;
+    }
+    return true;

[Michael Starzinger, 2013/01/15 11:12:37]

The original implementation of just comparing prototype and holder would still
suffice I think. But as discussed offline, it is probably safer to do a full
comparison of the whole chain anyways.

   }
 
  private:
-  Handle<JSObject> prototype_;
-  Handle<JSObject> holder_;
+  ZoneList< Handle<JSObject> > prototypes_;

[Michael Starzinger, 2013/01/15 11:12:37]

The rest of the code-base doesn't have a space between the opening angles, just
between the closing.

+  ZoneList< Handle<Map> > maps_;
 };
 
 
 class HCheckSmi: public HUnaryOperation {
  public:
   explicit HCheckSmi(HValue* value) : HUnaryOperation(value) {
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
   }
 
@@ skipping 1112 matching lines @@
   HSub(HValue* context, HValue* left, HValue* right)
       : HArithmeticBinaryOperation(context, left, right) {
     SetFlag(kCanOverflow);
   }
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   virtual HValue* Canonicalize();
 
   static HInstruction* NewHSub(Zone* zone,
-                              HValue* context,
-                              HValue* left,
-                              HValue* right);
+                               HValue* context,
+                               HValue* left,
+                               HValue* right);
 
   DECLARE_CONCRETE_INSTRUCTION(Sub)
 
  protected:
   virtual bool DataEquals(HValue* other) { return true; }
 
   virtual Range* InferRange(Zone* zone);
 };
 
 
@@ skipping 1841 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_