> On 27 Jul 2020, at 17:39, Konstantin Belousov <kostik...@gmail.com> wrote: > > On Mon, Jul 27, 2020 at 10:37:53AM -0400, Mark Johnston wrote: >> On Mon, Jul 27, 2020 at 11:27:40AM +0200, Paul FLOYD wrote: >>> Hi >>> >>> I'm investigating some of the remaining issues with Valgrind on FreeBSD. >>> One of the two remaining major issues that I'm aware of is with Valgrind >>> reading dwarf debuginfo from clang compiled binaries. The problem isn't >>> too bad with clang 8 on FreeBSD 12.1. On 13-CURRENT with clang 10 things >>> are noticeably worse. For GCC built binaries I'm not aware of any issues. >>> >>> I'm not familiar (yet) with the debuginfo code in Valgrind. >>> >>> To get me going, does anyone have any pointers to >>> - documentation on clang debuginfo > Clang generates DWARF which is documented by the DWARF standard(s), > available at http://dwarfstd.org/
The site seems to be down ATM. From what I’ve read, DWARF is somewhat flexible and allows for vendor extensions. For instance I’ve already seen DW_AT_GNU_all_call_sites and DW_GNU_all_tail_call_sites. > >>> - any info on differences wrt GCC (I have seen that GCC does have some >>> debuginfo extensions) > Gcc also generates DWARF. It is up to the compiler to interpret the standard > and provide compliant metadata according to it. > > But I would expect that the practical difference or troubles in parsing > the compiler' output is due to different versions of the used standard. > Both gcc and clang allow to specify which level of standard should be > used, see the description of the -gdwarf-<version> switch. > > Different versions of the same compiler might default to different > version of DWARF as well. > No, I don’t think that is the problem. Valgrind can read DWARF up to version 4 (not 5). If it encounters a version it does not know about it says so directly ==1602== Command: ./leak_dwarf5 ==1602== --1602-- WARNING: Serious error when reading debug info --1602-- When reading debug info from /usr/home/paulf/scratch/vg_examples/leak_dwarf5: --1602-- Ignoring non-Dwarf2/3/4 block in .debug_info --1602-- WARNING: Serious error when reading debug info --1602-- When reading debug info from /usr/home/paulf/scratch/vg_examples/leak_dwarf5: --1602-- parse_CU_Header: is neither DWARF2 nor DWARF3 nor DWARF4 ==1602== So I suspect that this is a question of dialect rather than version. A+ Paul _______________________________________________ freebsd-toolchain@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-toolchain To unsubscribe, send any mail to "freebsd-toolchain-unsubscr...@freebsd.org"
