Commit 7b536ff1 authored by Hans Wennborg's avatar Hans Wennborg
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Merging r259260: 

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r259260 | samsonov | 2016-01-29 15:07:14 -0800 (Fri, 29 Jan 2016) | 1 line

[UBSan] Add documentation for runtime issue suppression.
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llvm-svn: 259371
parent e0ea7cf2

clang/docs/UndefinedBehaviorSanitizer.rst

+32 −0
Original line number Diff line number Diff line
@@ -168,6 +168,38 @@ UndefinedBehaviorSanitizer supports ``src`` and ``fun`` entity types in 
: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

===================