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

src/x64/builtins-x64.cc

 // Copyright 2012 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_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 2030 matching lines @@
   __ leap(rsp, Operand(rsp, index.reg, index.scale, 1 * kPointerSize));
   __ PushReturnAddressFrom(rcx);
 }
 
 // static
 void Builtins::Generate_AllocateInNewSpace(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rdx    : requested object size (untagged)
   //  -- rsp[0] : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(rdx, rax, rcx, rdi, &runtime, NO_ALLOCATION_FLAGS);
-  __ Ret();
-
-  __ bind(&runtime);
   __ Integer32ToSmi(rdx, rdx);
   __ PopReturnAddressTo(rcx);
   __ Push(rdx);
   __ PushReturnAddressFrom(rcx);
   __ Move(rsi, Smi::FromInt(0));
   __ TailCallRuntime(Runtime::kAllocateInNewSpace);
 }
 
 // static
 void Builtins::Generate_AllocateInOldSpace(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rdx    : requested object size (untagged)
   //  -- rsp[0] : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(rdx, rax, rcx, rdi, &runtime, PRETENURE);
-  __ Ret();
-
-  __ bind(&runtime);
   __ Integer32ToSmi(rdx, rdx);
   __ PopReturnAddressTo(rcx);
   __ Push(rdx);
   __ Push(Smi::FromInt(AllocateTargetSpace::encode(OLD_SPACE)));
   __ PushReturnAddressFrom(rcx);
   __ Move(rsi, Smi::FromInt(0));
   __ TailCallRuntime(Runtime::kAllocateInTargetSpace);
 }
 
 void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
@@ skipping 881 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64