Incremental mode now works for x64. The only difference

src/arm/macro-assembler-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3148 matching lines @@
   jmp(&other_color);
 
   bind(&word_boundary);
   ldr(ip, MemOperand(bitmap_scratch, MemoryChunk::kHeaderSize + kPointerSize));
   tst(ip, Operand(1));
   b(second_bit == 1 ? ne : eq, has_color);
   bind(&other_color);
 }
 
 
+void MacroAssembler::IsDataObject(Register value,

[Lasse Reichstein, 2011/06/10 13:55:44]

JumpIfNotDataObject

[Erik Corry, 2011/06/10 21:57:29]

Done.

+                                  Register scratch,
+                                  Label* not_data_object) {

[Lasse Reichstein, 2011/06/10 13:55:44]

Should it have a distance too?

[Erik Corry, 2011/06/10 21:57:29]

No, ARM has fixed width instructions.

+  Label is_data_object;
+  ldr(scratch, FieldMemOperand(value, HeapObject::kMapOffset));
+  CompareRoot(scratch, Heap::kHeapNumberMapRootIndex);
+  b(eq, &is_data_object);
+  ASSERT(kConsStringTag == 1 && kIsConsStringMask == 1);
+  ASSERT(kNotStringTag == 0x80 && kIsNotStringMask == 0x80);
+  // If it's a string and it's not a cons string then it's an object that
+  // doesn't need scanning.
+  ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
+  tst(scratch, Operand(kIsConsStringMask | kIsNotStringMask));
+  // Jump if we need to mark it grey and push it.

[Lasse Reichstein, 2011/06/10 13:55:44]

Comment not related to function name or description.

[Erik Corry, 2011/06/10 21:57:29]

Deleted.

+  b(ne, not_data_object);
+  bind(&is_data_object);

[Lasse Reichstein, 2011/06/10 13:55:44]

This detects only HeapNumber and non-cons String.
It seems there are other data objects (Oddballs), but I guess they are
irrelevant because they are always in old-space?
I.e., add comment saying why.

[Erik Corry, 2011/06/10 21:57:29]

Done.

+}
+
+
 void MacroAssembler::GetMarkBits(Register addr_reg,
                                  Register bitmap_reg,
                                  Register mask_reg) {
   ASSERT(!AreAliased(addr_reg, bitmap_reg, mask_reg, no_reg));
   and_(bitmap_reg, addr_reg, Operand(~Page::kPageAlignmentMask));
   Ubfx(mask_reg, addr_reg, kPointerSizeLog2, Bitmap::kBitsPerCellLog2);
   const int kLowBits = kPointerSizeLog2 + Bitmap::kBitsPerCellLog2;
   Ubfx(ip, addr_reg, kLowBits, kPageSizeBits - kLowBits);
   add(bitmap_reg, bitmap_reg, Operand(ip, LSL, kPointerSizeLog2));
   mov(ip, Operand(1));
@@ skipping 96 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM