A64: Add support for --deopt-every-n-times for n != 2

A64: Add support for --deopt-every-n-times for n != 2

To match arm, the DeoptimizeIf*() methods need to invoke the
DeoptimizeHeader() method explicitly, so we do the check even if the
condition does not hold.

BUG=none
R=ulan@chromium.org, rodolph.perfetta@arm.com
LOG=n

Committed: https://code.google.com/p/v8/source/detail?r=19235

[jochen (gone - plz use gerrit), 2014-02-10 14:32:07]

PTAL

https://codereview.chromium.org/155723004/diff/1/src/a64/lithium-codegen-a64.cc
File src/a64/lithium-codegen-a64.cc (right):

https://codereview.chromium.org/155723004/diff/1/src/a64/lithium-codegen-a64....
src/a64/lithium-codegen-a64.cc:974: return false;
It doesn't really matter what we return here, because the call will never
return...

[jochen (gone - plz use gerrit), 2014-02-10 14:49:44]

disregard my comment... updated

[ulan, 2014-02-10 15:21:40]

https://codereview.chromium.org/155723004/diff/60001/src/a64/lithium-codegen-...
File src/a64/lithium-codegen-a64.cc (right):

https://codereview.chromium.org/155723004/diff/60001/src/a64/lithium-codegen-...
src/a64/lithium-codegen-a64.cc:973: __ Call(entry, RelocInfo::RUNTIME_ENTRY);
This works only if (frame_is_built_ && !info()->saves_caller_doubles()), right?

Instead of duplicating deoptimizing code here and in 
LCodeGen::Deoptimize, wouldn't it be better to pass a condition and labels to
this function? This function then could check the condition and
deopt_every_n_times counter and if we need to deopt it could jump to the
corresponding label.

[jochen (gone - plz use gerrit), 2014-02-10 16:05:58]

https://codereview.chromium.org/155723004/diff/60001/src/a64/lithium-codegen-...
File src/a64/lithium-codegen-a64.cc (right):

https://codereview.chromium.org/155723004/diff/60001/src/a64/lithium-codegen-...
src/a64/lithium-codegen-a64.cc:973: __ Call(entry, RelocInfo::RUNTIME_ENTRY);
On 2014/02/10 15:21:40, ulan wrote:
> This works only if (frame_is_built_ && !info()->saves_caller_doubles()),
right?

Before I added the jump table, we would always use Call(), and arm and x64 have
the same code, so I assume it'll always work

> Instead of duplicating deoptimizing code here and in 
> LCodeGen::Deoptimize, wouldn't it be better to pass a condition and labels to
> this function? This function then could check the condition and
> deopt_every_n_times counter and if we need to deopt it could jump to the
> corresponding label.

We could do this, but then we can't use the fancy Tbz() etc instructions to test
and branch.

[jochen (gone - plz use gerrit), 2014-02-10 16:07:50]

added ASSERT(frame_is_built_);

[ulan, 2014-02-10 16:12:53]

lgtm

[jochen (gone - plz use gerrit), 2014-02-10 16:34:08]

Committed patchset #4 manually as r19235 (presubmit successful).