[sr #108559] libtool binary wrappers fall prey to aggressive optimizations

[LRN]

URL:
  <http://savannah.gnu.org/support/?108559>

                 Summary: libtool binary wrappers fall prey to aggressive
optimizations
                 Project: GNU Libtool
            Submitted by: lrn
            Submitted on: Fri 02 May 2014 05:16:44 AM GMT
                Category: None
                Priority: 5 - Normal
                Severity: 3 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
        Operating System: None

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Details:

When building binary wrappers (say, for W32), libtool puts a MAGIC constant
string into them. Later on libtool greps the program for this string to see
whether this is a wrapper or a real program.

However, MAGIC string is not used in the program in any way, and gcc may
remove it. This does happen when building with -flto.

My proposal would be to make use of the string somehow to fool gcc into
leaving it alone. For example, this call:

           lt_fatal (__FILE__, __LINE__,
                    "unrecognized %s option: '%s'",
                    ltwrapper_option_prefix, argv[i]);

can be changed like this:

           lt_fatal (__FILE__, __LINE__,
                    "unrecognized %s option: '%s'\0%s",
                    ltwrapper_option_prefix, argv[i], MAGIC_EXE);





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