ARM: Load the heap number map into a register and keep it...

ARM: Load the heap number map into a register and keep it
there throughout the binary op stub (used for checking and
creating heap numbers).

Committed: http://code.google.com/p/v8/source/detail?r=4897

[Søren Thygesen Gjesse, 2010-06-17 14:15:25]

LGTM

http://codereview.chromium.org/2843010/diff/1/2
File src/arm/codegen-arm.cc (right):

http://codereview.chromium.org/2843010/diff/1/2#newcode7368
src/arm/codegen-arm.cc:7368: ASSERT(heap_number_map.is(r6));  // This is a
register that we don't use.
don't use -> don't otherwise use in this stub?

http://codereview.chromium.org/2843010/diff/1/2#newcode7762
src/arm/codegen-arm.cc:7762: ASSERT(heap_number_map.is(r6));  // This is a
register we don't use.
don't use -> don't otherwise use in this stub?

http://codereview.chromium.org/2843010/diff/1/2#newcode8012
src/arm/codegen-arm.cc:8012: Register num_map = r6;
num_map -> heap_number_map for consistency.

http://codereview.chromium.org/2843010/diff/1/6
File src/arm/macro-assembler-arm.cc (right):

http://codereview.chromium.org/2843010/diff/1/6#newcode1670
src/arm/macro-assembler-arm.cc:1670: // Store heap number map in the allocated
object.
Why not also use AssertRegisterIsRoot here?

[Erik Corry, 2010-06-17 19:27:09]

http://codereview.chromium.org/2843010/diff/1/2
File src/arm/codegen-arm.cc (right):

http://codereview.chromium.org/2843010/diff/1/2#newcode7368
src/arm/codegen-arm.cc:7368: ASSERT(heap_number_map.is(r6));  // This is a
register that we don't use.
On 2010/06/17 14:15:25, Søren Gjesse wrote:
> don't use -> don't otherwise use in this stub?

I delayed the allocation of r6 to avoid penalizing those programs that avoid
non-Smis.  And in the process, the need for this comment evaporated.

http://codereview.chromium.org/2843010/diff/1/2#newcode7762
src/arm/codegen-arm.cc:7762: ASSERT(heap_number_map.is(r6));  // This is a
register we don't use.
On 2010/06/17 14:15:25, Søren Gjesse wrote:
> don't use -> don't otherwise use in this stub?

Ditto.

http://codereview.chromium.org/2843010/diff/1/2#newcode8012
src/arm/codegen-arm.cc:8012: Register num_map = r6;
On 2010/06/17 14:15:25, Søren Gjesse wrote:
> num_map -> heap_number_map for consistency.

This variable went away!

http://codereview.chromium.org/2843010/diff/1/6
File src/arm/macro-assembler-arm.cc (right):

http://codereview.chromium.org/2843010/diff/1/6#newcode1670
src/arm/macro-assembler-arm.cc:1670: // Store heap number map in the allocated
object.
On 2010/06/17 14:15:25, Søren Gjesse wrote:
> Why not also use AssertRegisterIsRoot here?

Done.