Frees up LR on arm for use by the register allocator.

Frees up LR on arm for use by the register allocator.

This failed in my last attempt because LR was clobbered on
deopt. Now, LR is always cached in IP before the call to
the deopt stub, and restored on entry to the stub.

R=srdjan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=40686

[zra, 2014-09-24 22:15:01]

zra@google.com changed reviewers:
+ srdjan@google.com

[srdjan, 2014-09-24 22:36:02]

lgtm

https://codereview.chromium.org/602993002/diff/1/runtime/vm/flow_graph_compil...
File runtime/vm/flow_graph_compiler_arm.cc (right):

https://codereview.chromium.org/602993002/diff/1/runtime/vm/flow_graph_compil...
runtime/vm/flow_graph_compiler_arm.cc:187: __ mov(IP, Operand(LR));
Please add comment why this is necessary. Make sure to link in the comment to
GenerateDeoptimizationSequence.

[Florian Schneider, 2014-09-25 09:49:21]

fschneider@google.com changed reviewers:
+ fschneider@google.com

[Florian Schneider, 2014-09-25 09:49:22]

dbc:

https://codereview.chromium.org/602993002/diff/1/runtime/vm/intermediate_lang...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/602993002/diff/1/runtime/vm/intermediate_lang...
runtime/vm/intermediate_language_arm.cc:208: summary->set_temp(0,
Location::RegisterLocation(LR));
Calls clobber all registers, so I'm not sure if this is necessary.

[zra, 2014-09-25 18:11:27]

https://codereview.chromium.org/602993002/diff/1/runtime/vm/flow_graph_compil...
File runtime/vm/flow_graph_compiler_arm.cc (right):

https://codereview.chromium.org/602993002/diff/1/runtime/vm/flow_graph_compil...
runtime/vm/flow_graph_compiler_arm.cc:187: __ mov(IP, Operand(LR));
On 2014/09/24 22:36:02, srdjan wrote:
> Please add comment why this is necessary. Make sure to link in the comment to
> GenerateDeoptimizationSequence.

Done.

https://codereview.chromium.org/602993002/diff/1/runtime/vm/intermediate_lang...
File runtime/vm/intermediate_language_arm.cc (right):

https://codereview.chromium.org/602993002/diff/1/runtime/vm/intermediate_lang...
runtime/vm/intermediate_language_arm.cc:208: summary->set_temp(0,
Location::RegisterLocation(LR));
On 2014/09/25 09:49:22, Florian Schneider wrote:
> Calls clobber all registers, so I'm not sure if this is necessary.

Done.

[zra, 2014-09-25 19:28:31]

Committed patchset #2 (id:20001) manually as r40686 (presubmit successful).