Add LoadTaggedClassIdMayBeSmi to assembly and improve performance of inline cache stubs.

Add LoadTaggedClassIdMayBeSmi to assembly and improve performance of inline cache stubs.

R=zra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37011

[zra, 2014-06-04 18:54:59]

lgtm

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm.cc
File runtime/vm/assembler_arm.cc (right):

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm...
runtime/vm/assembler_arm.cc:1688: void
Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
tst(object, Operand(kSmiTagMask));
LoadImmediate(result, Smi::RawValue(kSmiCid), EQ);
LoadClassId(result, object, NE);
SmiTag(result, NE);

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm...
File runtime/vm/assembler_arm64.cc (right):

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm...
runtime/vm/assembler_arm64.cc:1076: void
Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
tsti(object, kSmiTagMask);
LoadImmediate(result, Smi::RawValue(kSmiCid), PP);
LoadClassId(temp, object, PP);  // Use TMP or pass in a scratch register for
'temp'.
csel(result, result, temp, EQ);

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_mip...
File runtime/vm/assembler_mips.cc (right):

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_mip...
runtime/vm/assembler_mips.cc:659: LoadImmediate(result, Smi::RawValue(kSmiCid));
If Smi::RawValue(kSmiCid) fits in 16 bits, you can load it with:

addiu(result, ZR, Immediate(Smi::RawValue(kSmiCid)));

and put it in the branch delay slot of b(&done);

[srdjan, 2014-06-04 20:08:04]

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm.cc
File runtime/vm/assembler_arm.cc (right):

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm...
runtime/vm/assembler_arm.cc:1688: void
Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
On 2014/06/04 18:55:00, zra wrote:
> tst(object, Operand(kSmiTagMask));
> LoadImmediate(result, Smi::RawValue(kSmiCid), EQ);
> LoadClassId(result, object, NE);
> SmiTag(result, NE);

Done and added condition to LoadClassId

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm...
File runtime/vm/assembler_arm64.cc (right):

https://codereview.chromium.org/313083008/diff/10001/runtime/vm/assembler_arm...
runtime/vm/assembler_arm64.cc:1076: void
Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
On 2014/06/04 18:55:00, zra wrote:
> tsti(object, kSmiTagMask);
> LoadImmediate(result, Smi::RawValue(kSmiCid), PP);
> LoadClassId(temp, object, PP);  // Use TMP or pass in a scratch register for
> 'temp'.
> csel(result, result, temp, EQ);

Discussed offline, leave it as it be since LoadClassId with object Smi is not
possible.

[srdjan, 2014-06-04 20:37:30]

Committed patchset #4 manually as r37011 (presubmit successful).