[Bug gdb/11760] New: Can't patch binary with gdb 7.1 on Mac OS X

["collberg at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

I'm unable to successfully patch a binary using gdb, on
Mac OS X. Depending on the exact commands, the 
results are slightly different, but they never "work" -
gdb never produces a correctly patched runnable binary.

Example:
=========================================
#include<stdio.h>

int main (int argc, char *argv[]) {
   int x = 6*argc;
   if (argc>1)
      printf("This is a test, %i\n", x);
   else
      printf("And here's another one, %i\n", x);
   return 0;
}

=========================================

 gcc -g -o test test.c

=========================================

> ~/bin/gdb -write test
GNU gdb (GDB) 7.1
This GDB was configured as "x86_64-apple-darwin10".
(gdb) break main
Breakpoint 1 at 0x100000eb7: file test.c, line 5.
(gdb) run

Breakpoint 1, main (argc=1, argv=0x7fff5fbff670) at test.c:5
5          int x = 6*argc;
(gdb) step
6          if (argc>1)
(gdb) x/i $pc
=> 0x100000ec6 <main+30>:       cmpl   $0x1,-0x14(%rbp)
(gdb) 
   0x100000eca <main+34>:       jle    0x100000ee2 <main+58>
(gdb)  set {unsigned char}0x0000000100000c4f = 0x7f
(gdb) cont
Continuing.
And here's another one, 6

Program exited normally.
(gdb) quit
unable to write unknown load command 0x22
warning: cannot close ".../test": File in wrong format

======================================

-- 
           Summary: Can't patch binary with gdb 7.1 on Mac OS X
           Product: gdb
           Version: 7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gdb
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: collberg at gmail dot com
                CC: gdb-prs at sourceware dot org
  GCC host triplet: Mac OS X 10.6.3
GCC target triplet: Mac OS X 10.6.3


http://sourceware.org/bugzilla/show_bug.cgi?id=11760

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