[llvm-branch-commits] [cfe-branch] r259371 - Merging r259260:

[Hans Wennborg via llvm-branch-commits]

Author: hans
Date: Mon Feb  1 11:10:12 2016
New Revision: 259371

URL: http://llvm.org/viewvc/llvm-project?rev=259371&view=rev
Log:
Merging r259260:
------------------------------------------------------------------------
r259260 | samsonov | 2016-01-29 15:07:14 -0800 (Fri, 29 Jan 2016) | 1 line

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

Modified:
    cfe/branches/release_38/   (props changed)
    cfe/branches/release_38/docs/UndefinedBehaviorSanitizer.rst

Propchange: cfe/branches/release_38/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Mon Feb  1 11:10:12 2016
@@ -1,4 +1,4 @@
 /cfe/branches/type-system-rewrite:134693-134817
-/cfe/trunk:257652,257695,257947,258110
+/cfe/trunk:257652,257695,257947,258110,259260
 /cfe/trunk/test:170344
 /cfe/trunk/test/SemaTemplate:126920

Modified: cfe/branches/release_38/docs/UndefinedBehaviorSanitizer.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/branches/release_38/docs/UndefinedBehaviorSanitizer.rst?rev=259371&r1=259370&r2=259371&view=diff
==============================================================================
--- cfe/branches/release_38/docs/UndefinedBehaviorSanitizer.rst (original)
+++ cfe/branches/release_38/docs/UndefinedBehaviorSanitizer.rst Mon Feb  1 11:10:12 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
 ===================