A bunch of tests in the gdb testsuite dealing with static variables inside function scopes have started failing recently with the latest development gcc. I simplified the test case down to a small program that shows that simply adding a small bit of unrelated code causes the DWARF information to disappear. Here is a typescript:
Script started on Tue 24 Oct 2006 08:58:44 PM MST $ cat b.c int bar () { static int funclocal = 4; /* In data section */ return funclocal; } int foo () { static int funclocal = 3; /* In Data section */ return funclocal; } #ifdef EXPOSEBUG void bell () { static int usedval; } #endif main () { extern void exit (int); exit (bar() + foo()); } $ gcc -g -o b b.c $ readelf --debug-dump b | grep funclocal DW_AT_name : (indirect string, offset: 0x0): funclocal DW_AT_name : (indirect string, offset: 0x0): funclocal DW_AT_name : (indirect string, offset: 0x0): funclocal 0x00000000 66756e63 6c6f6361 6c00 funclocal. $ gcc -DEXPOSEBUG -g -o b b.c $ readelf --debug-dump b | grep funclocal DW_AT_name : funclocal $ gdb b GNU gdb 6.5.50.20060923-cvs Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-linux-gnu"... Using host libthread_db library "/lib/libthread_db.so.1". (gdb) br foo Breakpoint 1 at 0x8048361: file b.c, line 10. (gdb) br bar Breakpoint 2 at 0x8048357: file b.c, line 4. (gdb) run Starting program: /media/backups/new/build/specifix/experimental/i686-pc-linux-gnu/gdb/gdb/testsuite/b Breakpoint 2, bar () at b.c:4 4 return funclocal; (gdb) p funclocal No symbol "funclocal" in current context. (gdb) c Continuing. Breakpoint 1, foo () at b.c:10 10 return funclocal; (gdb) p funclocal $1 = 3 (gdb) quit The program is running. Exit anyway? (y or n) y $ exit Script done on Tue 24 Oct 2006 08:59:51 PM MST -- Summary: DWARF information for function static variable is missing after unrelated code addition Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: major Priority: P3 Component: debug AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: fnf at specifixinc dot com GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29614