Add the PUSH instruction to ARM integrated assembler.

Add the PUSH instruction to ARM integrated assembler.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4334
R=stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=6cab56197153807395ff60d1d672b0098dd97a8a

[Karl, 2015-11-05 22:46:28]

Description was changed from

==========
Add the PUSH instruction to ARM integrated assembler.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4334
==========

to

==========
Add the PUSH instruction to ARM integrated assembler.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4334
==========

[Karl, 2015-11-05 22:46:28]

kschimpf@google.com changed reviewers:
+ jpp@chromium.org, sehr@chromium.org, stichnot@chromium.org

[Jim Stichnoth, 2015-11-06 00:59:10]

otherwise lgtm

https://codereview.chromium.org/1412963008/diff/1/src/IceAssemblerARM32.cpp
File src/IceAssemblerARM32.cpp (right):

https://codereview.chromium.org/1412963008/diff/1/src/IceAssemblerARM32.cpp#n...
src/IceAssemblerARM32.cpp:546: Registers >= (1 << 16))
What is this magic 16?  Can you document it in a constexpr?

https://codereview.chromium.org/1412963008/diff/1/tests_lit/assembler/arm32/p...
File tests_lit/assembler/arm32/push-pop.ll (right):

https://codereview.chromium.org/1412963008/diff/1/tests_lit/assembler/arm32/p...
tests_lit/assembler/arm32/push-pop.ll:72: call void @DoSomething();
Add a comment describing the trick: the over-eager O2 register allocator puts v1
and v2 into callee-save registers since the call instruction kills the scratch
registers, requiring these callee-save registers to be pushed/popped in the
prolog/epilog.

[Karl, 2015-11-06 17:14:15]

Committed patchset #2 (id:20001) manually as
6cab56197153807395ff60d1d672b0098dd97a8a (presubmit successful).

[Karl, 2015-11-06 17:14:30]

https://codereview.chromium.org/1412963008/diff/1/src/IceAssemblerARM32.cpp
File src/IceAssemblerARM32.cpp (right):

https://codereview.chromium.org/1412963008/diff/1/src/IceAssemblerARM32.cpp#n...
src/IceAssemblerARM32.cpp:546: Registers >= (1 << 16))
On 2015/11/06 00:59:09, stichnot wrote:
> What is this magic 16?  Can you document it in a constexpr?

Done.

https://codereview.chromium.org/1412963008/diff/1/tests_lit/assembler/arm32/p...
File tests_lit/assembler/arm32/push-pop.ll (right):

https://codereview.chromium.org/1412963008/diff/1/tests_lit/assembler/arm32/p...
tests_lit/assembler/arm32/push-pop.ll:72: call void @DoSomething();
On 2015/11/06 00:59:09, stichnot wrote:
> Add a comment describing the trick: the over-eager O2 register allocator puts
v1
> and v2 into callee-save registers since the call instruction kills the scratch
> registers, requiring these callee-save registers to be pushed/popped in the
> prolog/epilog.

Done.