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From: "dje at google dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug breakpoints/15826] Slow symbol lookups during conditional
 breakpoints
Date: Thu, 15 Aug 2013 18:42:00 -0000
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http://sourceware.org/bugzilla/show_bug.cgi?id=15826

--- Comment #4 from dje at google dot com ---
---snip---
#include <unistd.h>

int x = 0;

void
forever ()
{
  while (1)
    {
      ++x;
      usleep (100000); // 0.1 second                                            
    }
}

int
main ()
{
  forever ();
  return 0;
}
---snip---

$ g++ -g foo.cc -o foo

# Following is cribbed from memory, heads up.
$ gdb gdb
(top-gdb) b lookup_symbol_aux_quick
(top-gdb) run foo
(gdb) start
(gdb) b 11   # line with usleep
(gdb) cond 2 x % 10 == 0
(gdb) c
(top-gdb) bt

or some such.

The key is that bool isn't in the debug info, and c++ expression parsing wants
to cast the value to bool, so it ultimately calls the language lookup routine
for bool, which first checks the debug info (and if that fails uses the builtin
type).

Caching lookups, especially failed ones, will help, though gdb can still be
smarter with "standard" types.

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