path: root/src/stdio/__stdio_exit.c
diff options
authorRich Felker <>2014-07-16 21:32:06 -0400
committerRich Felker <>2014-07-16 21:32:06 -0400
commita6adb2bcd8145353943377d6119c1d7a4242bae1 (patch)
tree0ea88fa60243c6ac696917cbb4264da0f59b786b /src/stdio/__stdio_exit.c
parentc463e11eda8326aacee2ac1d516954a9574a2dcd (diff)
work around constant folding bug 61144 in gcc 4.9.0 and 4.9.1
previously we detected this bug in configure and issued advice for a workaround, but this turned out not to work. since then gcc 4.9.0 has appeared in several distributions, and now 4.9.1 has been released without a fix despite this being a wrong code generation bug which is supposed to be a release-blocker, per gcc policy. since the scope of the bug seems to affect only data objects (rather than functions) whose definitions are overridable, and there are only a very small number of these in musl, I am just changing them from const to volatile for the time being. simply removing the const would be sufficient to make gcc 4.9.1 work (the non-const case was inadvertently fixed as part of another change in gcc), and this would also be sufficient with 4.9.0 if we forced -O0 on the affected files or on the whole build. however it's cleaner to just remove all the broken compiler detection and use volatile, which will ensure that they are never constant-folded. the quality of a non-broken compiler's output should not be affected except for the fact that these objects are no longer const and thus possibly add a few bytes to data/bss. this change can be reconsidered and possibly reverted at some point in the future when the broken gcc versions are no longer relevant.
Diffstat (limited to 'src/stdio/__stdio_exit.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/src/stdio/__stdio_exit.c b/src/stdio/__stdio_exit.c
index e4380aaf..716e5f73 100644
--- a/src/stdio/__stdio_exit.c
+++ b/src/stdio/__stdio_exit.c
@@ -1,6 +1,6 @@
#include "stdio_impl.h"
-static FILE *const dummy_file = 0;
+static FILE *volatile dummy_file = 0;
weak_alias(dummy_file, __stdin_used);
weak_alias(dummy_file, __stdout_used);
weak_alias(dummy_file, __stderr_used);