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From: "chantry.xavier at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug breakpoints/12156] New: cannot break on static functions with gcc flto (link time optimization)
Date: Sat, 23 Oct 2010 14:51:00 -0000	[thread overview]
Message-ID: <bug-12156-4717@http.sourceware.org/bugzilla/> (raw)

http://sourceware.org/bugzilla/show_bug.cgi?id=12156

           Summary: cannot break on static functions with gcc flto (link
                    time optimization)
           Product: gdb
           Version: unknown
            Status: NEW
          Severity: normal
          Priority: P2
         Component: breakpoints
        AssignedTo: unassigned@sourceware.org
        ReportedBy: chantry.xavier@gmail.com


Created attachment 5082
  --> http://sourceware.org/bugzilla/attachment.cgi?id=5082
minimal test case with one static function foo

When compiling with gcc -flto, static symbols get a number suffix/extension.
e.g. foo becomes foo.2043

break foo<tab> expands to break foo.2043, but neither works.

The only way to actually set the break point is to specify the address
directly.

[xavier@xps-m1530 ~]$ gcc -flto test.c 
[xavier@xps-m1530 ~]$ objdump -d a.out | grep foo
00000000004004c4 <foo.2043>:
  4004d8:    e8 e7 ff ff ff           callq  4004c4 <foo.2043>
[xavier@xps-m1530 ~]$ gdb a.out 
GNU gdb (GDB) 7.2.50.20101022-cvs
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/xavier/a.out...(no debugging symbols found)...done.
(gdb) break foo.2043 
Can't find member of namespace, class, struct, or union named "foo.2043"
Hint: try 'foo.2043<TAB> or 'foo.2043<ESC-?>
(Note leading single quote.)
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (foo.2043) pending.
(gdb) break foo
Function "foo" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (foo) pending.
(gdb) run
Starting program: /home/xavier/a.out 
bar

Program exited with code 04.
(gdb) break *0x4004c4
Breakpoint 3 at 0x4004c4
(gdb) run
Starting program: /home/xavier/a.out 

Breakpoint 3, 0x00000000004004c4 in foo.2043 ()
(gdb) c
Continuing.
bar

Program exited with code 04.
(gdb)

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             reply	other threads:[~2010-10-23 14:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-23 14:51 chantry.xavier at gmail dot com [this message]
2010-11-15 17:11 ` [Bug breakpoints/12156] " tromey at redhat dot com
2010-11-21 18:08 ` chantry.xavier at gmail dot com

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