[turbofan] Initial version of allocation folding and write barrier elimination.

src/arm64/builtins-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.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/arm64/frames-arm64.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
@@ skipping 2740 matching lines @@
   __ Jump(masm->isolate()->builtins()->Construct(), RelocInfo::CODE_TARGET);
 }
 
 // static
 void Builtins::Generate_AllocateInNewSpace(MacroAssembler* masm) {
   ASM_LOCATION("Builtins::Generate_AllocateInNewSpace");
   // ----------- S t a t e -------------
   //  -- x1 : requested object size (untagged)
   //  -- lr : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(x1, x0, x2, x3, &runtime, NO_ALLOCATION_FLAGS);
-  __ Ret();
-
-  __ Bind(&runtime);
   __ SmiTag(x1);
   __ Push(x1);
   __ Move(cp, Smi::FromInt(0));
   __ TailCallRuntime(Runtime::kAllocateInNewSpace);
 }
 
 // static
 void Builtins::Generate_AllocateInOldSpace(MacroAssembler* masm) {
   ASM_LOCATION("Builtins::Generate_AllocateInOldSpace");
   // ----------- S t a t e -------------
   //  -- x1 : requested object size (untagged)
   //  -- lr : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(x1, x0, x2, x3, &runtime, PRETENURE);
-  __ Ret();
-
-  __ Bind(&runtime);
   __ SmiTag(x1);
   __ Move(x2, Smi::FromInt(AllocateTargetSpace::encode(OLD_SPACE)));
   __ Push(x1, x2);
   __ Move(cp, Smi::FromInt(0));
   __ TailCallRuntime(Runtime::kAllocateInTargetSpace);
 }
 
 void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
   ASM_LOCATION("Builtins::Generate_ArgumentsAdaptorTrampoline");
   // ----------- S t a t e -------------
@@ skipping 139 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM