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[Bug libc/11781] New: Interoperability problems between malloc hook and GCC 4.5.0 optimizations
- From: "opensource3141 at gmail dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 1 Jul 2010 16:49:36 -0000
- Subject: [Bug libc/11781] New: Interoperability problems between malloc hook and GCC 4.5.0 optimizations
- Reply-to: sourceware-bugzilla at sourceware dot org
With the improved optimizations of GCC 4.5.0 it is possible to have code that
manipulates __malloc_hook before and after a call to malloc get optimized out.
This is because GCC is assuming that malloc is a builtin function that does not
access global variables, while GLIBC malloc does in fact rely on the global
variable __malloc_hook.
A detailed exposition of this is found in the GCC bugzilla:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44736
I am filing this bug in the GLIBC bugzilla as per a request from the GCC
developer. A GCC developer suggested marking the __malloc_hook (and associated
other hooks) as volatile in the GLIBC header file; however, this may or may not
be the right thing to do.
--
Summary: Interoperability problems between malloc hook and GCC
4.5.0 optimizations
Product: glibc
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper at redhat dot com
ReportedBy: opensource3141 at gmail dot com
CC: glibc-bugs at sources dot redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=11781
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