I've managed to distill this problem into a trivial Lazarus project. Unpack the tarball, and build this project as .compiled indicates.
Run it under gdb 6.6 with a break-point placed as commented. Try and step into TChild.Create at this point - gdb SEGV. Rebuild with DWARF2 and it run without crashing gdb. At least that's what I'm seeing here (Debian Etch, FPC SVN 8427, GDB 6.6). I hope this helps. I will try and isolate it further. Cheers, Bruce. Bruce Tulloch wrote: > Hi Jonas, > > Unfortunately GDB (6.6) still barfs on FPC (SVN 8427) generated stabs > sometimes when performing a backtrace or printing certain objects in > our application. As mentioned earlier, we'll do what we can to abstract > the problem into the small demonstration program we can send you. For > the time being we'll use DWARF2 as despite some remaining problems with > that (reported in another email) it does not crash GDB. > > Cheers, Bruce. > > Bruce Tulloch wrote: >> I have encountered a problem using GDB (6.4.90-debian) with FPC (2.0.4 >> or 2.1.4). In a nutshell, GDB sometimes barfs on FPC generated stabs. >> >> If the program is compiled with -g (stabs format) the debugger works >> but attempts to print some data structures or produce a back-trace >> can result in a SEGV in GDB (ie, GDB itself crashes). >> >> If the program is compiled with -gd (DBX format) or -gw (dwarf) GDB >> works correctly without crashing but reference to source files that >> are in directories other than the current directory have a (relative) >> path prepended to the name which breaks other things (notably the >> emacs/GUD and Lazarus front ends). >> >> By way of example, with GDB run in the (project home) directory >> >> /home/bruce/vc/ >> >> with dwarf symbols GDB reports: >> >> (gdb) info source >> Current source file is src//Widget.pas >> Compilation directory is src/ >> Located in /home/bruce/vc/src/Widget.pas >> Contains 637 lines. >> Source language is pascal. >> Compiled with unknown debugging format. >> Does not include preprocessor macro info. >> >> When the program is compiled with stabs I get: >> >> (gdb) info source >> Current source file is Widget.pas >> Compilation directory is src/ >> Located in /home/bruce/vc/src/Widget.pas >> Contains 637 lines. >> Source language is pascal. >> Compiled with stabs debugging format. >> Does not include preprocessor macro info. >> >> which is correct (but GDB is otherwise unusable due the stabs problem). >> >> My (2) questions are: >> >> [1] has anyone else seen the GDB crashing problem when a program is >> compiled with stabs info? >> >> [2] is the filename problem with dwarf encoded symbols an FPC bug or >> is there some configuration I'm missing somehere. >> >> Note that in all cases I've compiled the program (which is a port of a >> a working Delphi application) with no optimizations or other bells and >> whistles enabled. >> >> Many thanks for any advice about what I might be doing wrong. >> >> Otherwise consider this a bug report :-) >> >> Cheers, Bruce Tulloch. >> _______________________________________________ >> fpc-devel maillist - fpc-devel@lists.freepascal.org >> http://lists.freepascal.org/mailman/listinfo/fpc-devel >> > _______________________________________________ > fpc-devel maillist - fpc-devel@lists.freepascal.org > http://lists.freepascal.org/mailman/listinfo/fpc-devel >
gdb-stabs-bomb.tgz
Description: application/compressed
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