Make x64 to use the RecordWrite stub. This is a step towards getting

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
===================================================================
--- src/x64/assembler-x64.h	(revision 8207)
+++ src/x64/assembler-x64.h	(working copy)
@@ -1374,6 +1374,18 @@
 
   int pc_offset() const { return static_cast<int>(pc_ - buffer_); }
 
+  // Used for patching the code stream while it is being emitted.
+  inline byte get_opcode(int offset) {

[Lasse Reichstein, 2011/06/07 14:02:53]

Rename to get_byte/set_byte. Or read_byte/patch_byte.
There is nothing opcode-specific in this.

[Erik Corry, 2011/06/08 10:38:55]

No, but it makes the call site clearer.

[Lasse Reichstein, 2011/06/08 10:58:46]

I don't see us using get_opcode anywhere. Just remove it.

[Lasse Reichstein, 2011/06/08 10:58:46]

The call site can make its own local functions by any name, which call the
generic method on the assembler.

The generic method is there now, and public, for anyone to use at any time.
For that reason alone, I think it should be less bound to the current use-case.
E.g., I think it should take a zero-based index, not a pc-based index. It's easy
to convert between the two (using pc_offset()).

Or, preferably, replace it with a macro like:
 PatchableNearJump(byte opcode, Label* label) {
   db(opcode);
   emit_near_disp(label);
 }

but there is a visibility issue to work around with that, since MacroAssembler
cant see emit_near_disp. Perhaps make a db_near_disp(Label*) method for that.

[Erik Corry, 2011/06/08 11:27:11]

I now use set_byte_at and pc_offset instead.

[Erik Corry, 2011/06/08 11:27:11]

It was used in an assert

+    ASSERT(offset < 0);
+    ASSERT(pc_ + offset >= buffer_);
+    return pc_[offset];
+  }
+  inline void set_opcode(int offset, byte opcode) {
+    ASSERT(offset < 0);
+    ASSERT(pc_ + offset >= buffer_);
+    pc_[offset] = opcode;
+  }
+
   PositionsRecorder* positions_recorder() { return &positions_recorder_; }
 
   // Check if there is less than kGap bytes available in the buffer.