i#1114 JIT optimization: add option and annotations

Commit log for first patchset:
---------------
i#1114 JIT optimization: add option and annotations

Adds option -opt_jit to enable the JIT optimization. Adds
the annotations for identifying JIT code, and registers them
in an otherwise empty stub of the new jit_opt core module.
---------------

[bruening, 2015-12-11 20:46:41]

LGTM w/ comments

https://codereview.appspot.com/280950043/diff/1/core/dynamo.c
File core/dynamo.c (right):

https://codereview.appspot.com/280950043/diff/1/core/dynamo.c#newcode967
core/dynamo.c:967: jitopt_exit();
There is both a fast exit and a slow exit: you only added to the slow exit, so I
assume there's nothing to be done in release build.

https://codereview.appspot.com/280950043/diff/1/core/jit_opt.h
File core/jit_opt.h (right):

https://codereview.appspot.com/280950043/diff/1/core/jit_opt.h#newcode4
core/jit_opt.h:4: #ifdef ANNOTATIONS /* around whole file */
What about the auto-infer scheme?  It doesn't need annotations, and won't its
code live here?

https://codereview.appspot.com/280950043/diff/1/core/lib/dr_annotations.h
File core/lib/dr_annotations.h (right):

https://codereview.appspot.com/280950043/diff/1/core/lib/dr_annotations.h#new...
core/lib/dr_annotations.h:57: #define DYNAMORIO_ANNOTATE_MANAGE_CODE_AREA(start,
size) \
Why are they "DR_DECLARE_ANNOTATION" above but different here?

https://codereview.appspot.com/280950043/diff/1/core/optionsx.h
File core/optionsx.h (right):

https://codereview.appspot.com/280950043/diff/1/core/optionsx.h#newcode316
core/optionsx.h:316: OPTION_DEFAULT(bool, opt_jit, false,
How about an XXX i#... for turning this to true by default

[Byron, 2015-12-11 22:43:13]

Committed as
https://github.com/DynamoRIO/dynamorio/commit/a492fa3e19c9e27a5e3b109e3c98efa...

Final commit log: 
---------------
i#1114 JIT optimization: add option and annotations

Adds option -opt_jit to enable the JIT optimization. Adds
the annotations for identifying JIT code, and registers them
in an otherwise empty stub of the new jit_opt core module.

Review-URL: https://codereview.appspot.com/280950043
---------------

[Byron, 2015-12-11 22:44:54]

https://codereview.appspot.com/280950043/diff/1/core/dynamo.c
File core/dynamo.c (right):

https://codereview.appspot.com/280950043/diff/1/core/dynamo.c#newcode967
core/dynamo.c:967: jitopt_exit();
On 2015/12/11 20:46:41, bruening wrote:
> There is both a fast exit and a slow exit: you only added to the slow exit, so
I
> assume there's nothing to be done in release build.

Acknowledged.

https://codereview.appspot.com/280950043/diff/1/core/jit_opt.h
File core/jit_opt.h (right):

https://codereview.appspot.com/280950043/diff/1/core/jit_opt.h#newcode4
core/jit_opt.h:4: #ifdef ANNOTATIONS /* around whole file */
On 2015/12/11 20:46:41, bruening wrote:
> What about the auto-infer scheme?  It doesn't need annotations, and won't its
> code live here?

Done.

https://codereview.appspot.com/280950043/diff/1/core/lib/dr_annotations.h
File core/lib/dr_annotations.h (right):

https://codereview.appspot.com/280950043/diff/1/core/lib/dr_annotations.h#new...
core/lib/dr_annotations.h:57: #define DYNAMORIO_ANNOTATE_MANAGE_CODE_AREA(start,
size) \
On 2015/12/11 20:46:41, bruening wrote:
> Why are they "DR_DECLARE_ANNOTATION" above but different here?

Done.

https://codereview.appspot.com/280950043/diff/1/core/optionsx.h
File core/optionsx.h (right):

https://codereview.appspot.com/280950043/diff/1/core/optionsx.h#newcode316
core/optionsx.h:316: OPTION_DEFAULT(bool, opt_jit, false,
On 2015/12/11 20:46:41, bruening wrote:
> How about an XXX i#... for turning this to true by default

Done.