Introduce the SetFp function in StackHandler

Introduce the SetFp function in StackHandler

The FP setting is different for X32 than the other platforms as
kFPOnStackSize is double the kPointerSize and we have to clear the
higher 32 bits to 0.

R=danno@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=15966

[haitao.feng, 2013-07-24 06:09:17]

Address danno's comment on https://codereview.chromium.org/18014003/.

https://codereview.chromium.org/20073004/diff/1/src/frames.h
File src/frames.h (left):

https://codereview.chromium.org/20073004/diff/1/src/frames.h#oldcode180
src/frames.h:180: };
+2 * kPCOnStackSize assumes kFPOnStackSize == kPCOnStackSize.

[danno, 2013-07-24 13:28:57]

https://codereview.chromium.org/20073004/diff/1/src/frames.cc
File src/frames.cc (right):

https://codereview.chromium.org/20073004/diff/1/src/frames.cc#newcode1525
src/frames.cc:1525: StackHandlerConstants::kSlotCount == 6);
I think this assert needs to be:

STATIC_ASSERT(StackHandlerConstants::kSlotCount >= 5)

because I think the reason is to ensure that the array indices used below will
all be valid, but as long as there are 5 or more slots, everything is OK.

https://codereview.chromium.org/20073004/diff/1/src/frames.cc#newcode1547
src/frames.cc:1547: StackHandlerConstants::kSlotCount == 6);
See comment above

[haitao.feng, 2013-07-24 13:44:17]

danno, thanks for the review.

https://codereview.chromium.org/20073004/diff/1/src/frames.cc
File src/frames.cc (right):

https://codereview.chromium.org/20073004/diff/1/src/frames.cc#newcode1525
src/frames.cc:1525: StackHandlerConstants::kSlotCount == 6);
On 2013/07/24 13:28:57, danno wrote:
> I think this assert needs to be:
> 
> STATIC_ASSERT(StackHandlerConstants::kSlotCount >= 5)
> 
> because I think the reason is to ensure that the array indices used below will
> all be valid, but as long as there are 5 or more slots, everything is OK.

Done.

https://codereview.chromium.org/20073004/diff/1/src/frames.cc#newcode1525
src/frames.cc:1525: StackHandlerConstants::kSlotCount == 6);
On 2013/07/24 13:28:57, danno wrote:
> I think this assert needs to be:
> 
> STATIC_ASSERT(StackHandlerConstants::kSlotCount >= 5)
> 
> because I think the reason is to ensure that the array indices used below will
> all be valid, but as long as there are 5 or more slots, everything is OK.

Done.

https://codereview.chromium.org/20073004/diff/1/src/frames.cc#newcode1547
src/frames.cc:1547: StackHandlerConstants::kSlotCount == 6);
On 2013/07/24 13:28:57, danno wrote:
> See comment above

Done.

[danno, 2013-07-30 11:03:53]

lgtm

[haitao.feng, 2013-07-31 00:00:16]

Committed patchset #2 manually as r15966 (presubmit successful).