This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [wwwdocs] Suggest UBsan in https://gcc.gnu.org/bugs/
- From: Jonathan Wakely <jwakely at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Gerald Pfeifer <gerald at pfeifer dot com>, Joseph Myers <joseph at codesourcery dot com>, Sandra Loosemore <sandra at codesourcery dot com>
- Date: Tue, 6 Oct 2015 12:16:26 +0100
- Subject: Re: [wwwdocs] Suggest UBsan in https://gcc.gnu.org/bugs/
- Authentication-results: sourceware.org; auth=none
- References: <20151006105401 dot GP12094 at redhat dot com>
On 06/10/15 11:54 +0100, Jonathan Wakely wrote:
For many non-bugs UBsan is at least as likely to reveal it as
-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations so we
should tell people to try that before wasting time in Bugzilla.
OK for wwwdocs?
Index: htdocs/bugs/index.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/bugs/index.html,v
retrieving revision 1.116
diff -u -r1.116 index.html
--- htdocs/bugs/index.html 5 Jul 2014 21:52:32 -0000 1.116
+++ htdocs/bugs/index.html 6 Oct 2015 10:50:32 -0000
@@ -50,7 +50,11 @@
with <code>gcc -Wall -Wextra</code> and see whether this shows anything
wrong with your code. Similarly, if compiling with
<code>-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations</code>
-makes a difference, your code probably is not correct.</p>
+makes a difference, your code probably is not correct.
+If compiling with <code>-fsanitize=undefined</code> is supported by your
+version of GCC and produces any run-time errors your code is definitely
+not correct.
+</p>
<h2>Summarized bug reporting instructions</h2>
On IRC Markus pointed out that ubsan works in all supported releases,
and that some code that gets ubsan errors still shows real gcc bugs,
so here's an updated patch.
Index: htdocs/bugs/index.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/bugs/index.html,v
retrieving revision 1.116
diff -u -r1.116 index.html
--- htdocs/bugs/index.html 5 Jul 2014 21:52:32 -0000 1.116
+++ htdocs/bugs/index.html 6 Oct 2015 11:15:04 -0000
@@ -50,7 +50,9 @@
with <code>gcc -Wall -Wextra</code> and see whether this shows anything
wrong with your code. Similarly, if compiling with
<code>-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations</code>
-makes a difference, your code probably is not correct.</p>
+makes a difference, or if compiling with <code>-fsanitize=undefined</code>
+produces any run-time errors, then your code is probably not correct.
+</p>
<h2>Summarized bug reporting instructions</h2>