Use immediates when possible for HBoundsCheck and HLoadKeyedFastElement

Use immediates when possible for HBoundsCheck and HLoadKeyedFastElement

Committed: http://code.google.com/p/v8/source/detail?r=8943

[Jakob Kummerow, 2011-08-10 09:10:26]

Danno: PTAL.

Kevin: The comments in lithium-{ia32,x64}.h are based on what you told me
yesterday. Please check whether I got them right.

[danno, 2011-08-10 11:03:46]

http://codereview.chromium.org/7608020/diff/1/src/ia32/lithium-codegen-ia32.cc
File src/ia32/lithium-codegen-ia32.cc (right):

http://codereview.chromium.org/7608020/diff/1/src/ia32/lithium-codegen-ia32.c...
src/ia32/lithium-codegen-ia32.cc:2312: elements, (key << times_pointer_size) +
FixedArray::kHeaderSize));
overflow check in the spirit of lithium-codegen-ia32.cc:51? Also in the 64-bit
version?

http://codereview.chromium.org/7608020/diff/1/src/ia32/lithium-codegen-ia32.c...
src/ia32/lithium-codegen-ia32.cc:3118: DeoptimizeIf(below_equal,
instr->environment());
overflow check in the spirit of lithium-codegen-ia32.cc:51? Also in the 64-bit
version?

http://codereview.chromium.org/7608020/diff/1/src/x64/lithium-codegen-x64.cc
File src/x64/lithium-codegen-x64.cc (right):

http://codereview.chromium.org/7608020/diff/1/src/x64/lithium-codegen-x64.cc#...
src/x64/lithium-codegen-x64.cc:2313: int key =
ToInteger32(LConstantOperand::cast(instr->key()));
Move into a "GetOperanXXXX" function. Or can you even use existing
"BuildFastArrayOperand"?

[Jakob Kummerow, 2011-08-10 12:22:47]

http://codereview.chromium.org/7608020/diff/1/src/ia32/lithium-codegen-ia32.cc
File src/ia32/lithium-codegen-ia32.cc (right):

http://codereview.chromium.org/7608020/diff/1/src/ia32/lithium-codegen-ia32.c...
src/ia32/lithium-codegen-ia32.cc:2312: elements, (key << times_pointer_size) +
FixedArray::kHeaderSize));
On 2011/08/10 11:03:46, danno wrote:
> overflow check in the spirit of lithium-codegen-ia32.cc:51? Also in the 64-bit
> version?

Done (by using BuildFastArrayOperand).

http://codereview.chromium.org/7608020/diff/1/src/ia32/lithium-codegen-ia32.c...
src/ia32/lithium-codegen-ia32.cc:3118: DeoptimizeIf(below_equal,
instr->environment());
On 2011/08/10 11:03:46, danno wrote:
> overflow check in the spirit of lithium-codegen-ia32.cc:51? Also in the 64-bit
> version?

As discussed offline, nothing to overflow-check here.

http://codereview.chromium.org/7608020/diff/1/src/x64/lithium-codegen-x64.cc
File src/x64/lithium-codegen-x64.cc (right):

http://codereview.chromium.org/7608020/diff/1/src/x64/lithium-codegen-x64.cc#...
src/x64/lithium-codegen-x64.cc:2313: int key =
ToInteger32(LConstantOperand::cast(instr->key()));
On 2011/08/10 11:03:46, danno wrote:
> Move into a "GetOperanXXXX" function. Or can you even use existing
> "BuildFastArrayOperand"?

Done.

[danno, 2011-08-10 13:38:59]

LGTM

[Kevin Millikin (Chromium), 2011-08-11 07:42:59]

Look OK.  I'd probably focus more on the what and why of AssignEnvironment and
AssignPointerMap and not the particulars of other functions.  Move the three
together and then have something like:

// Assign an environment to an instruction.  An instruction which can deoptimize
must have an environment.
... AssignEnvironment...

// Assign a pointer map to an instruction.  An instruction which can trigger a
GC or a lazy deoptimization must have a pointer map.
... AssignEnvironment...

// Mark a call for the register allocator.  Assign a pointer map to support GC
and lazy deoptimization.  Assign an environment to support eager deoptimization
if CAN_DEOPTIMIZE_EAGERLY.
... MarkAsCall...