r259260 - [UBSan] Add documentation for runtime issue suppression.

[Hans Wennborg via cfe-commits]

Yes, that seems like a good idea. Go ahead and merge (or let me know
if you'd prefer me to do it).

On Fri, Jan 29, 2016 at 3:14 PM, Alexey Samsonov <vonosmas at gmail.com> wrote:
> Hans, do you think it makes sense to merge this patch into 3.8?
>
> On Fri, Jan 29, 2016 at 3:07 PM, Alexey Samsonov via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
>>
>> Author: samsonov
>> Date: Fri Jan 29 17:07:14 2016
>> New Revision: 259260
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=259260&view=rev
>> Log:
>> [UBSan] Add documentation for runtime issue suppression.
>>
>> Modified:
>>     cfe/trunk/docs/UndefinedBehaviorSanitizer.rst
>>
>> Modified: cfe/trunk/docs/UndefinedBehaviorSanitizer.rst
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/UndefinedBehaviorSanitizer.rst?rev=259260&r1=259259&r2=259260&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/docs/UndefinedBehaviorSanitizer.rst (original)
>> +++ cfe/trunk/docs/UndefinedBehaviorSanitizer.rst Fri Jan 29 17:07:14 2016
>> @@ -168,6 +168,38 @@ UndefinedBehaviorSanitizer supports ``sr
>>  :doc:`SanitizerSpecialCaseList`, that can be used to suppress error
>> reports
>>  in the specified source files or functions.
>>
>> +Runtime suppressions
>> +--------------------
>> +
>> +Sometimes you can suppress UBSan error reports for specific files,
>> functions,
>> +or libraries without recompiling the code. You need to pass a path to
>> +suppression file in a ``UBSAN_OPTIONS`` environment variable.
>> +
>> +.. code-block:: bash
>> +
>> +    UBSAN_OPTIONS=suppressions=MyUBSan.supp
>> +
>> +You need to specify a :ref:`check <ubsan-checks>` you are suppressing and
>> the
>> +bug location. For example:
>> +
>> +.. code-block:: bash
>> +
>> +  signed-integer-overflow:file-with-known-overflow.cpp
>> +  alignment:function_doing_unaligned_access
>> +  vptr:shared_object_with_vptr_failures.so
>> +
>> +There are several limitations:
>> +
>> +* Sometimes your binary must have enough debug info and/or symbol table,
>> so
>> +  that the runtime could figure out source file or function name to match
>> +  against the suppression.
>> +* It is only possible to suppress recoverable checks. For the example
>> above,
>> +  you can additionally pass
>> +  ``-fsanitize-recover=signed-integer-overflow,alignment,vptr``, although
>> +  most of UBSan checks are recoverable by default.
>> +* Check groups (like ``undefined``) can't be used in suppressions file,
>> only
>> +  fine-grained checks are supported.
>> +
>>  Supported Platforms
>>  ===================
>>
>>
>>
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>
>
>
>
> --
> Alexey Samsonov
> vonosmas at gmail.com