i#1734: implement simple -fuzz_bbcov

Commit log for first patchset:
---------------
i#1734: implement simple -fuzz_bbcov

Implements simple -fuzz_bbcov for bitflip based mutator.
---------------

[bruening, 2016-11-01 14:20:38]

LGTM w/ comments

https://codereview.appspot.com/312060043/diff/1/drmemory/optionsx.h
File drmemory/optionsx.h (right):

https://codereview.appspot.com/312060043/diff/1/drmemory/optionsx.h#newcode685
drmemory/optionsx.h:685: OPTION_CLIENT_BOOL(drmemscope, fuzz_bbcov, false,
Should it be fuzz_coverage instead?

https://codereview.appspot.com/312060043/diff/1/drmemory/optionsx.h#newcode687
drmemory/optionsx.h:687: "Enable basic block coverage guided fuzzing for bit
flipping based mutator.")
What about for a custom mutator?  How would they enable coverage?  This same
option, right?  If so, please update the description as it's not just bit flip.

[zhaoqin, 2016-11-01 15:25:17]

Commit log for latest patchset:
---------------
i#1734: implement simple -fuzz_coverage

Implements simple -fuzz_coverage for default mutator.

Updates docs about enabling feedback guided mutation.

Review-URL: https://codereview.appspot.com/312060043
---------------

[zhaoqin, 2016-11-01 15:25:24]

https://codereview.appspot.com/312060043/diff/1/drmemory/optionsx.h
File drmemory/optionsx.h (right):

https://codereview.appspot.com/312060043/diff/1/drmemory/optionsx.h#newcode685
drmemory/optionsx.h:685: OPTION_CLIENT_BOOL(drmemscope, fuzz_bbcov, false,
On 2016/11/01 14:20:37, bruening wrote:
> Should it be fuzz_coverage instead?

Done.

https://codereview.appspot.com/312060043/diff/1/drmemory/optionsx.h#newcode687
drmemory/optionsx.h:687: "Enable basic block coverage guided fuzzing for bit
flipping based mutator.")
On 2016/11/01 14:20:38, bruening wrote:
> What about for a custom mutator?  How would they enable coverage?  This same
> option, right?  If so, please update the description as it's not just bit
flip.

Done.

[bruening, 2016-11-01 15:33:30]

LGTM w/ comments

https://codereview.appspot.com/312060043/diff/20001/drmemory/docs/fuzzer.dox
File drmemory/docs/fuzzer.dox (right):

https://codereview.appspot.com/312060043/diff/20001/drmemory/docs/fuzzer.dox#...
drmemory/docs/fuzzer.dox:152: The option -fuzz_coverage must be specified for
any custom mutator
\p

https://codereview.appspot.com/312060043/diff/20001/drmemory/optionsx.h
File drmemory/optionsx.h (right):

https://codereview.appspot.com/312060043/diff/20001/drmemory/optionsx.h#newco...
drmemory/optionsx.h:687: "Enable basic block coverage guided fuzzing.  A custom
mutator that implements drfuzz_mutator_feedback must use this option to enable
the coverage feedback guided mutation.")
So no need to mention bitflip, b/c you're saying numeric doesn't make sense here
and thus the built-in mutators are all done?

[zhaoqin, 2016-11-01 15:41:00]

https://codereview.appspot.com/312060043/diff/20001/drmemory/docs/fuzzer.dox
File drmemory/docs/fuzzer.dox (right):

https://codereview.appspot.com/312060043/diff/20001/drmemory/docs/fuzzer.dox#...
drmemory/docs/fuzzer.dox:152: The option -fuzz_coverage must be specified for
any custom mutator
On 2016/11/01 15:33:30, bruening wrote:
> \p

Done.

https://codereview.appspot.com/312060043/diff/20001/drmemory/optionsx.h
File drmemory/optionsx.h (right):

https://codereview.appspot.com/312060043/diff/20001/drmemory/optionsx.h#newco...
drmemory/optionsx.h:687: "Enable basic block coverage guided fuzzing.  A custom
mutator that implements drfuzz_mutator_feedback must use this option to enable
the coverage feedback guided mutation.")
On 2016/11/01 15:33:30, bruening wrote:
> So no need to mention bitflip, b/c you're saying numeric doesn't make sense
here
> and thus the built-in mutators are all done?

If we think harder, there might be way to do so for numeric's.
Also there are other mutators like dictionary based. But I guess that it is hard
to cover all cases. So maybe I should mention bitflip.

[zhaoqin, 2016-11-01 15:42:11]

Commit log for latest patchset:
---------------
i#1734: implement simple -fuzz_coverage

Implements simple -fuzz_coverage for default mutator.

Updates docs about enabling feedback guided mutation.

Review-URL: https://codereview.appspot.com/312060043
---------------

[zhaoqin, 2016-11-01 15:59:59]

Committed as
https://github.com/DynamoRIO/drmemory/commit/95f57c22ff4fb8bd7785c59c3d122f5c...

Final commit log: 
---------------
i#1734: implement simple -fuzz_coverage

Implements simple -fuzz_coverage for default mutator.

Updates docs about enabling feedback guided mutation.

Review-URL: https://codereview.appspot.com/312060043
---------------