Remove prototype checks for leaf maps in optimized code.

src/ia32/lithium-codegen-ia32.cc

 // 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 85 matching lines @@
   ASSERT(is_done());
   code->set_stack_slots(GetStackSlotCount());
   code->set_safepoint_table_offset(safepoints_.GetCodeOffset());
   if (FLAG_weak_embedded_maps_in_optimized_code) {
     RegisterDependentCodeForEmbeddedMaps(code);
   }
   PopulateDeoptimizationData(code);
   if (!info()->IsStub()) {
     Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(code);
   }
+  for (int i = 0 ; i < prototype_maps_.length(); i++) {
+    prototype_maps_.at(i)->AddDependentCode(
+        DependentCode::kPrototypeCheckGroup, code);
+  }
 }
 
 
 void LCodeGen::Abort(const char* reason) {
   info()->set_bailout_reason(reason);
   status_ = ABORTED;
 }
 
 
 void LCodeGen::Comment(const char* format, ...) {
@@ skipping 796 matching lines @@
       }
     }
   }
 #ifdef VERIFY_HEAP
   // This disables verification of weak embedded maps after full GC.
   // AddDependentCode can cause a GC, which would observe the state where
   // this code is not yet in the depended code lists of the embedded maps.
   NoWeakEmbeddedMapsVerificationScope disable_verification_of_embedded_maps;
 #endif
   for (int i = 0; i < maps.length(); i++) {
-    maps.at(i)->AddDependentCode(code);
+    maps.at(i)->AddDependentCode(DependentCode::kWeaklyEmbeddedGroup, code);
   }
 }
 
 
 void LCodeGen::PopulateDeoptimizationData(Handle<Code> code) {
   int length = deoptimizations_.length();
   if (length == 0) return;
   Handle<DeoptimizationInputData> data =
       factory()->NewDeoptimizationInputData(length, TENURED);
 
@@ skipping 4385 matching lines @@
 
 void LCodeGen::DoCheckPrototypeMaps(LCheckPrototypeMaps* instr) {
   ASSERT(instr->temp()->Equals(instr->result()));
   Register reg = ToRegister(instr->temp());
 
   ZoneList<Handle<JSObject> >* prototypes = instr->prototypes();
   ZoneList<Handle<Map> >* maps = instr->maps();
 
   ASSERT(prototypes->length() == maps->length());
 
-  for (int i = 0; i < prototypes->length(); i++) {
-    __ LoadHeapObject(reg, prototypes->at(i));
-    DoCheckMapCommon(reg, maps->at(i), ALLOW_ELEMENT_TRANSITION_MAPS, instr);
+  // TODO(ulan): Move this check to hydrogen and split HCheckPrototypeMaps
+  // into two instruction: one that checks the prototypes and another that
+  // loads the holder (HConstant). Find a way to do it without breaking
+  // parallel recompilation.
+  if (instr->hydrogen()->CanOmitPrototypeChecks()) {
+    for (int i = 0; i < maps->length(); i++) {
+      prototype_maps_.Add(maps->at(i), info()->zone());
+    }
+    __ LoadHeapObject(reg, prototypes->at(prototypes->length() - 1));
+  } else {
+    for (int i = 0; i < prototypes->length(); i++) {
+      __ LoadHeapObject(reg, prototypes->at(i));
+      DoCheckMapCommon(reg, maps->at(i), ALLOW_ELEMENT_TRANSITION_MAPS, instr);
+    }
   }
 }
 
 
 void LCodeGen::DoAllocateObject(LAllocateObject* instr) {
   class DeferredAllocateObject: public LDeferredCode {
    public:
     DeferredAllocateObject(LCodeGen* codegen, LAllocateObject* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     virtual void Generate() { codegen()->DoDeferredAllocateObject(instr_); }
@@ skipping 830 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32