Here is a patch to correct a previous gprof bug that was only partially
fixed. Apparently it is possible for GCC to clone its own cloned
functions.
This problem manifested in a large g++ application which I cannot
provide in source form. Furthermore, simplification of that example
eliminates the problem with high probability. The best evidence I can
provide is the following gdb session showing the boundary between two
functions that demonstrates such a "clone of a clone":
(gdb) x/5i 0x7a7ae8
0x7a7ae8 <_ZN10sims_Event15startSimulationEv+552>:
callq 0x7a6f40 <_ZN19trno_WarningMessagelsEPKc.clone.4>
0x7a7aed <_ZN10sims_Event15startSimulationEv+557>:
jmp 0x7a7ab8 <_ZN10sims_Event15startSimulationEv+504>
0x7a7aef: nop
0x7a7af0
<_ZNKSt6vectorIPN10sims_Event9EventLinkESaIS2_EE12_M_check_lenEmPKc.clone.45.clone.53>:
push %rbp
0x7a7af1
<_ZNKSt6vectorIPN10sims_Event9EventLinkESaIS2_EE12_M_check_lenEmPKc.clone.45.clone.53+1>:
mov %rsp,%rbp
(gdb)
Note the .clone.45.clone.53 suffix on the symbol.
The following patch accepts function symbols that match the following
extended regular expression:
^[^\$\.]*(\.(clone\.)?[0-9]+)+$
and so accepts the following symbols:
foo.123
foo.clone.23
foo.clone.1.clone.2
foo.2.clone.6.clone.9
foo.2.1.clone.3.4.clone.5
This errs on the side of accepting more cases than the relevent
mechanisms are likely to produce (e.g., the last example).
David
--- orig/gprof/corefile.c 2011-06-06 10:07:57.406964819 -0400
+++ fixed/gprof/corefile.c 2011-06-06 10:15:10.198544726 -0400
@@ -389,16 +389,21 @@
if (*name == '.')
{
- /* Allow GCC cloned functions. */
- if (strlen (name) > 7 && strncmp (name, ".clone.", 7) == 0)
- name += 6;
-
- /* Do not discard nested subprograms (those
- which end with .NNN, where N are digits). */
- for (name++; *name; name++)
- if (! ISDIGIT (*name))
+ /* Allow both nested subprograms and GCC cloned functions.
+ Apparently, GCC can clone both of these. */
+ do {
+ if (strlen (name) > 7 && strncmp (name, ".clone.", 7) == 0)
+ name += 6;
+ int digit_seen = 0;
+ /* Do not discard nested subprograms (those
+ which end with .NNN, where N are digits). */
+ for (name++; *name; name++)
+ if (digit_seen && *name == '.') break;
+ else if (ISDIGIT (*name))
+ digit_seen = 1;
+ else
return 0;
-
+ } while (*name == '.');
break;
}
}
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