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[Bug libc/11781] New: Interoperability problems between malloc hook and GCC 4.5.0 optimizations


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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