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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