From 6c512830d2ff9f1d9fcf308312fdb3843f17ee59 Mon Sep 17 00:00:00 2001
From: George Burgess IV <george.burgess.iv@gmail.com>
Date: Mon, 25 Apr 2016 19:21:45 +0000
Subject: [PATCH] [Docs] Clarify what the object-size sanitizer does.
Currently, the UBSan docs make it sound like the object-size sanitizer
will only detect out-of-bounds reads/writes. It also catches some
operations that don't necessarily access memory (invalid downcasts,
calls of methods on invalid pointers, ...). This patch adds a note
about this behavior in the docs.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@267447 91177308-0d34-0410-b5e6-96231b3b80d8
---
docs/UndefinedBehaviorSanitizer.rst | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/docs/UndefinedBehaviorSanitizer.rst b/docs/UndefinedBehaviorSanitizer.rst
index 2a133501dd9..1002729f05d 100644
--- a/docs/UndefinedBehaviorSanitizer.rst
+++ b/docs/UndefinedBehaviorSanitizer.rst
@@ -92,11 +92,14 @@ Available checks are:
parameter which is declared to never be null.
- ``-fsanitize=null``: Use of a null pointer or creation of a null
reference.
- - ``-fsanitize=object-size``: An attempt to use bytes which the
- optimizer can determine are not part of the object being
- accessed. The sizes of objects are determined using
- ``__builtin_object_size``, and consequently may be able to detect
- more problems at higher optimization levels.
+ - ``-fsanitize=object-size``: An attempt to potentially use bytes which
+ the optimizer can determine are not part of the object being accessed.
+ This will also detect some types of undefined behavior that may not
+ directly access memory, but are provably incorrect given the size of
+ the objects involved, such as invalid downcasts and calling methods on
+ invalid pointers. These checks are made in terms of
+ ``__builtin_object_size``, and consequently may be able to detect more
+ problems at higher optimization levels.
- ``-fsanitize=return``: In C++, reaching the end of a
value-returning function without returning a value.
- ``-fsanitize=returns-nonnull-attribute``: Returning null pointer
--
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