[crankshaft] Fragmentation-free allocation folding.

src/crankshaft/x64/lithium-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.
 
 #include "src/crankshaft/x64/lithium-x64.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_X64
 
@@ skipping 2390 matching lines @@
 LInstruction* LChunkBuilder::DoStringCharFromCode(HStringCharFromCode* instr) {
   LOperand* char_code = UseRegister(instr->value());
   LOperand* context = UseAny(instr->context());
   LStringCharFromCode* result =
       new(zone()) LStringCharFromCode(context, char_code);
   return AssignPointerMap(DefineAsRegister(result));
 }
 
 
 LInstruction* LChunkBuilder::DoAllocate(HAllocate* instr) {
-  info()->MarkAsDeferredCalling();
-  LOperand* context = UseAny(instr->context());
-  LOperand* size = instr->size()->IsConstant()
-      ? UseConstant(instr->size())
-      : UseTempRegister(instr->size());
-  LOperand* temp = TempRegister();
-  LAllocate* result = new(zone()) LAllocate(context, size, temp);
-  return AssignPointerMap(DefineAsRegister(result));
+  LOperand* size = instr->size()->IsConstant() ? UseConstant(instr->size())
+                                               : UseRegister(instr->size());
+  if (instr->IsAllocationFolded()) {
+    LOperand* temp = TempRegister();
+    LFastAllocate* result = new (zone()) LFastAllocate(size, temp);
+    return DefineAsRegister(result);
+  } else {
+    info()->MarkAsDeferredCalling();
+    LOperand* context = UseAny(instr->context());
+    LOperand* temp = TempRegister();
+    LAllocate* result = new (zone()) LAllocate(context, size, temp);
+    return AssignPointerMap(DefineAsRegister(result));
+  }
 }
 
 
 LInstruction* LChunkBuilder::DoOsrEntry(HOsrEntry* instr) {
   DCHECK(argument_count_ == 0);
   allocator_->MarkAsOsrEntry();
   current_block_->last_environment()->set_ast_id(instr->ast_id());
   return AssignEnvironment(new(zone()) LOsrEntry);
 }
 
@@ skipping 163 matching lines @@
   LOperand* index = UseTempRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64