Improve write barriers in optimized code.

src/arm/macro-assembler-arm.h

 // 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.
 
 #ifndef V8_ARM_MACRO_ASSEMBLER_ARM_H_
 #define V8_ARM_MACRO_ASSEMBLER_ARM_H_
 
 #include "src/assembler.h"
 #include "src/frames.h"
 #include "src/globals.h"
@@ skipping 19 matching lines @@
 enum TaggingMode {
   // Tag the result.
   TAG_RESULT,
   // Don't tag
   DONT_TAG_RESULT
 };
 
 
 enum RememberedSetAction { EMIT_REMEMBERED_SET, OMIT_REMEMBERED_SET };
 enum SmiCheck { INLINE_SMI_CHECK, OMIT_SMI_CHECK };
+enum PointersToHereCheck {
+  kPointersToHereMaybeInteresting,
+  kPointersToHereAreAlwaysInteresting
+};
 enum LinkRegisterStatus { kLRHasNotBeenSaved, kLRHasBeenSaved };
 
 
 Register GetRegisterThatIsNotOneOf(Register reg1,
                                    Register reg2 = no_reg,
                                    Register reg3 = no_reg,
                                    Register reg4 = no_reg,
                                    Register reg5 = no_reg,
                                    Register reg6 = no_reg);
 
@@ skipping 187 matching lines @@
   // The offset is the offset from the start of the object, not the offset from
   // the tagged HeapObject pointer.  For use with FieldOperand(reg, off).
   void RecordWriteField(
       Register object,
       int offset,
       Register value,
       Register scratch,
       LinkRegisterStatus lr_status,
       SaveFPRegsMode save_fp,
       RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
-      SmiCheck smi_check = INLINE_SMI_CHECK);
+      SmiCheck smi_check = INLINE_SMI_CHECK,
+      PointersToHereCheck pointers_to_here_check_for_value =
+          kPointersToHereMaybeInteresting);
 
   // As above, but the offset has the tag presubtracted.  For use with
   // MemOperand(reg, off).
   inline void RecordWriteContextSlot(
       Register context,
       int offset,
       Register value,
       Register scratch,
       LinkRegisterStatus lr_status,
       SaveFPRegsMode save_fp,
       RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
-      SmiCheck smi_check = INLINE_SMI_CHECK) {
+      SmiCheck smi_check = INLINE_SMI_CHECK,
+      PointersToHereCheck pointers_to_here_check_for_value =
+          kPointersToHereMaybeInteresting) {
     RecordWriteField(context,
                      offset + kHeapObjectTag,
                      value,
                      scratch,
                      lr_status,
                      save_fp,
                      remembered_set_action,
-                     smi_check);
+                     smi_check,
+                     pointers_to_here_check_for_value);
   }
 
+  void RecordWriteForMap(
+      Register object,
+      Register map,
+      Register dst,
+      LinkRegisterStatus lr_status,
+      SaveFPRegsMode save_fp);
+
   // For a given |object| notify the garbage collector that the slot |address|
   // has been written.  |value| is the object being stored. The value and
   // address registers are clobbered by the operation.
   void RecordWrite(
       Register object,
       Register address,
       Register value,
       LinkRegisterStatus lr_status,
       SaveFPRegsMode save_fp,
       RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
-      SmiCheck smi_check = INLINE_SMI_CHECK);
+      SmiCheck smi_check = INLINE_SMI_CHECK,
+      PointersToHereCheck pointers_to_here_check_for_value =
+          kPointersToHereMaybeInteresting);
 
   // Push a handle.
   void Push(Handle<Object> handle);
   void Push(Smi* smi) { Push(Handle<Smi>(smi, isolate())); }
 
   // Push two registers.  Pushes leftmost register first (to highest address).
   void Push(Register src1, Register src2, Condition cond = al) {
     ASSERT(!src1.is(src2));
     if (src1.code() > src2.code()) {
       stm(db_w, sp, src1.bit() | src2.bit(), cond);
@@ skipping 1304 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_MACRO_ASSEMBLER_ARM_H_