Clean up the x86 assembler API.

Clean up the x86 assembler API.

The API is inconsistent about when a register must be coerced to an operand
and when it can be used as a register.  Simplify usage by never requiring it
to be wrapped.

R=fschneider@chromium.org
BUG=
TEST=

Committed: http://code.google.com/p/v8/source/detail?r=9507

[Kevin Millikin (Chromium), 2011-09-30 13:28:48]

It turns out that having the assembler API based on the x86 instruction encoding
is not as convenient as we thought it would be.

[Yang, 2011-09-30 13:42:19]

Drive by.

http://codereview.chromium.org/8086021/diff/1/src/ia32/assembler-ia32.h
File src/ia32/assembler-ia32.h (right):

http://codereview.chromium.org/8086021/diff/1/src/ia32/assembler-ia32.h#newco...
src/ia32/assembler-ia32.h:350: bool is_reg_only() const;
Is this still necessary if Operand wrapper has been removed?

[Kevin Millikin (Chromium), 2011-09-30 14:23:54]

Good idea.

http://codereview.chromium.org/8086021/diff/1/src/ia32/assembler-ia32.h
File src/ia32/assembler-ia32.h (right):

http://codereview.chromium.org/8086021/diff/1/src/ia32/assembler-ia32.h#newco...
src/ia32/assembler-ia32.h:350: bool is_reg_only() const;
On 2011/09/30 13:42:20, Yang wrote:
> Is this still necessary if Operand wrapper has been removed?

For now it is.  Under the hood it's the same implementation as before, but I
made the Operand(Register) constructor private.

I think it would be a good idea to get rid of that constructor and clean up the
encodings, but that's work for a separate change.

[fschneider, 2011-10-03 11:19:26]

LGTM.