- Remove extra jumps from store barrier on x64.

runtime/vm/assembler_x64.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
@@ skipping 861 matching lines @@
 
 
 void Assembler::addq(const Address& address, Register reg) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitOperandREX(reg, address, REX_W);
   EmitUint8(0x01);
   EmitOperand(reg & 7, address);
 }
 
 
+void Assembler::adcl(Register dst, Register src) {

[Vyacheslav Egorov (Google), 2012/06/22 10:36:28]

please add a test for this instruction in assembler tests

+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  Operand operand(src);
+  EmitOperandREX(dst, operand, REX_NONE);
+  EmitUint8(0x13);
+  EmitOperand(dst & 7, operand);
+}
+
+
 void Assembler::subl(Register dst, Register src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   Operand operand(src);
   EmitOperandREX(dst, operand, REX_NONE);
   EmitUint8(0x2B);
   EmitOperand(dst & 7, operand);
 }
 
 
 void Assembler::cdq() {
@@ skipping 506 matching lines @@
     ASSERT(reg != TMP);
     LoadObject(TMP, object);
     cmpq(reg, TMP);
   }
 }
 
 
 void Assembler::StoreIntoObjectFilter(Register object,
                                       Register value,
                                       Label* no_update) {
-  // Check that 'value' is a new object.  Store buffer updates are not
-  // required when storing a smi or an old object.
-  testl(value, Immediate(kNewObjectAlignmentOffset | kHeapObjectTag));
-  j(PARITY_ODD, no_update, Assembler::kNearJump);
-  j(ZERO, no_update, Assembler::kNearJump);
-  // Check that 'object' is an old object.  A store buffer update is
-  // not required when storing into a new object.
-  testl(object, Immediate(kNewObjectAlignmentOffset));
+  andl(value, Immediate(0x5));
+  shrl(value, Immediate(1));
+  adcl(value, object);
+  andl(value, Immediate(0x7));
+  cmpl(value, Immediate(0x4));
   j(NOT_ZERO, no_update, Assembler::kNearJump);
 }
 
 
 void Assembler::StoreIntoObject(Register object,
                                 const FieldAddress& dest,
                                 Register value) {
   movq(dest, value);
 
   Label done;
+  pushq(value);
   StoreIntoObjectFilter(object, value, &done);
   // A store buffer update is required.
-  pushq(RAX);
+  if (value != RAX) pushq(RAX);
   leaq(RAX, dest);
   call(&StubCode::UpdateStoreBufferLabel());
-  popq(RAX);
+  if (value != RAX) popq(RAX);
   Bind(&done);
+  popq(value);
 }
 
 
 void Assembler::StoreIntoObjectNoBarrier(Register object,
                                          const FieldAddress& dest,
                                          Register value) {
   movq(dest, value);
 #if defined(DEBUG)
   Label done;
+  pushq(value);
   StoreIntoObjectFilter(object, value, &done);
   Stop("Store buffer update is required");
   Bind(&done);
+  popq(value);
 #endif  // defined(DEBUG)
   // No store buffer update.
 }
 
 
 void Assembler::DoubleNegate(XmmRegister d) {
   static const struct ALIGN16 {
     uint64_t a;
     uint64_t b;
   } double_negate_constant =
@@ skipping 266 matching lines @@
     comments.SetCommentAt(i, comments_[i]->comment());
   }
 
   return comments;
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64