Reland parts of 'Use weak cells in map checks in polymorphic ICs'

src/arm64/lithium-codegen-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/arm64/lithium-gap-resolver-arm64.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 5001 matching lines @@
   __ Debug("LDebugBreak", 0, BREAK);
 }
 
 
 void LCodeGen::DoDeclareGlobals(LDeclareGlobals* instr) {
   DCHECK(ToRegister(instr->context()).is(cp));
   Register scratch1 = x5;
   Register scratch2 = x6;
   DCHECK(instr->IsMarkedAsCall());
 
-  ASM_UNIMPLEMENTED_BREAK("DoDeclareGlobals");

[mvstanton, 2014/12/02 13:45:20]

What is this about?

[ulan, 2014/12/02 13:56:06]

DoDeclareGlobals is actually implemented. The assert was there as a guard
because DoDeclareGlobals wasn't used in any of our tests. It starts triggering
in one of the tests if maps polymorphic ICs are weak.

   // TODO(all): if Mov could handle object in new space then it could be used
   // here.
   __ LoadHeapObject(scratch1, instr->hydrogen()->pairs());
   __ Mov(scratch2, Smi::FromInt(instr->hydrogen()->flags()));
   __ Push(cp, scratch1, scratch2);  // The context is the first argument.
   CallRuntime(Runtime::kDeclareGlobals, 3, instr);
 }
 
 
 void LCodeGen::DoDeferredStackCheck(LStackCheck* instr) {
@@ skipping 1010 matching lines @@
   Handle<ScopeInfo> scope_info = instr->scope_info();
   __ Push(scope_info);
   __ Push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 
 } }  // namespace v8::internal