Mark Kettenis wrote: > > Date: Mon, 26 Nov 2012 20:10:06 +0100 (CET) > > From: "Ulrich Weigand" <uweig...@de.ibm.com> > > > > Hello, > > > > I noticed what appears to be a long-standing bug in generating .dwarf_frame > > sections with GCC on Linux on PowerPC. > > > > ... > > > > So I'm wondering where to go from here. I guess we could: > > > > 1. Bring GCC (and gas) behaviour in compliance with the documented ABI > > by removing the #undef DBX_REGISTER_NUMBER and changing gas's > > md_reg_eh_frame_to_debug_frame to the original implementation from > > Jakub's patch. That would make GDB work well on new files, but > > there are a large number of binaries out there where we continue > > to have the same behaviour as today ... > > > > 2. Leave GCC and gas as-is and modify GDB to expect GCC numbering in > > .dwarf_frame, except for the condition code register. This would > > break debugging of files built with GCC 4.0 and 4.1 unless we > > want to add a special hack for that. > > > > 3. Like 2., but remove the condition code hack: simply use identical > > numbers in .eh_frame and .dwarf_frame. This would make PowerPC > > like other Linux platforms in that respect. > > > > Thoughts? > > What do other compilers (in particular XLC) do? From a GDB standpoint > it would be a major PITA if different compilers would use different > encodings for .dwarf_frame.
In my tests XLC (version 12.1 on Linux) seems to consistently use the GCC register numbering in both .eh_frame and .dwarf_frame. LLVM also consistently uses the GCC register numbering. Looks like this would be another argument for variant 3 ... Bye, Ulrich -- Dr. Ulrich Weigand GNU Toolchain for Linux on System z and Cell BE ulrich.weig...@de.ibm.com