A64: Fix some compile errors when building for Android.

A64: Fix some compile errors when building for Android.

 - replace __arm__ define checks with __aarch64__
 - add 64 bit ucontext_t struct definition
 - fix V8_HOST_ARCH_A64 compile errors in sampler.cc
 - add aarch64 brk assembly instruction for debug break

R=ulan@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18961

[rmcilroy, 2014-01-30 03:53:08]

PTAL.

I've not tried running it yet, but this gets us most of the way through the
compile.

[ulan, 2014-01-30 08:46:33]

[+Rodolph fyi]

LGTM

[Rodolph Perfetta (ARM), 2014-01-30 11:17:15]

https://codereview.chromium.org/148913008/diff/1/src/a64/cpu-a64.cc
File src/a64/cpu-a64.cc (right):

https://codereview.chromium.org/148913008/diff/1/src/a64/cpu-a64.cc#newcode29
src/a64/cpu-a64.cc:29: #ifdef __aarch64__
The current port does not use syscall for cache flushing as aarch64 allows it to
be perform in user space. We may consider syscall for some cases in the future
as superuser instructions provide finer control.

https://codereview.chromium.org/148913008/diff/1/src/platform-linux.cc
File src/platform-linux.cc (right):

https://codereview.chromium.org/148913008/diff/1/src/platform-linux.cc#newcod...
src/platform-linux.cc:446: #elif defined(__aarch64__)
there is already a __aarch64__ case 2 lines up, but brk is probably a better
choice.

[rmcilroy, 2014-01-30 18:16:42]

Thanks!

https://codereview.chromium.org/148913008/diff/1/src/a64/cpu-a64.cc
File src/a64/cpu-a64.cc (right):

https://codereview.chromium.org/148913008/diff/1/src/a64/cpu-a64.cc#newcode29
src/a64/cpu-a64.cc:29: #ifdef __aarch64__
On 2014/01/30 11:17:15, Rodolph Perfetta (ARM) wrote:
> The current port does not use syscall for cache flushing as aarch64 allows it
to
> be perform in user space. We may consider syscall for some cases in the future
> as superuser instructions provide finer control.

Done.

https://codereview.chromium.org/148913008/diff/1/src/platform-linux.cc
File src/platform-linux.cc (right):

https://codereview.chromium.org/148913008/diff/1/src/platform-linux.cc#newcod...
src/platform-linux.cc:446: #elif defined(__aarch64__)
On 2014/01/30 11:17:15, Rodolph Perfetta (ARM) wrote:
> there is already a __aarch64__ case 2 lines up, but brk is probably a better
> choice.

Ahh, missed the previous one.  Removed it and kept this one.

[rmcilroy, 2014-01-30 18:17:17]

Committed patchset #2 manually as r18961 (presubmit successful).