On Thu, Dec 08, 2022 at 09:11:54AM -0500, Marek Polacek via Gcc-patches wrote: > On Thu, Dec 08, 2022 at 08:25:26AM +0100, Florian Weimer wrote: > > * Marek Polacek via Gcc-patches: > > > > > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi > > > index 726392409b6..2de14466dd3 100644 > > > --- a/gcc/doc/invoke.texi > > > +++ b/gcc/doc/invoke.texi > > > @@ -16510,6 +16510,14 @@ The option cannot be combined with > > > @option{-fsanitize=thread} or > > > @option{-fsanitize=hwaddress}. Note that the only target > > > @option{-fsanitize=hwaddress} is currently supported on is AArch64. > > > > > > +To get more accurate stack traces, it is possible to use options such as > > > +@option{-O} (which, for instance, prevents most function inlining), > > > +@option{-fno-optimize-sibling-calls} (which prevents optimizing sibling > > > +and tail recursive calls), or @option{-fno-ipa-icf} (which disables > > > Identical > > > +Code Folding for functions and read-only variables). Since multiple runs > > > +of the program may yield backtraces with different addresses due to ASLR, > > > +it may be desirable to turn off ASLR: @samp{setarch `uname -m` -R > > > ./prog}. > > > > What about -fasynchronous-unwind-tables? It should help if ASAN ever > > reports stray segmentation faults. Whether it also helps in general > > depends on whether ASAN maintains ABI around its instrumentation. > > I'm not sure. Someone else will have to decide if we want to mention > that option as well.
-fasynchronous-unwind-tables is on by default on many targets, so I wouldn't mention it: grep asynchronous_unwind_tables common/*/*/* config/*/* common/config/aarch64/aarch64-common.cc: { OPT_LEVELS_ALL, OPT_fasynchronous_unwind_tables, NULL, 1 }, common/config/i386/i386-common.cc: opts->x_flag_asynchronous_unwind_tables = 2; common/config/loongarch/loongarch-common.cc: { OPT_LEVELS_ALL, OPT_fasynchronous_unwind_tables, NULL, 1 }, common/config/rs6000/rs6000-common.cc: opts->x_flag_asynchronous_unwind_tables = 1; common/config/s390/s390-common.cc: opts->x_flag_asynchronous_unwind_tables = 1; config/i386/i386-options.cc: if (opts->x_flag_asynchronous_unwind_tables == 2) config/i386/i386-options.cc: opts->x_flag_asynchronous_unwind_tables = !USE_IX86_FRAME_POINTER; config/mips/mips.cc: && !global_options_set.x_flag_asynchronous_unwind_tables) config/mips/mips.cc: flag_asynchronous_unwind_tables = 1; config/rs6000/rs6000.cc: && !OPTION_SET_P (flag_asynchronous_unwind_tables)) config/rs6000/rs6000.cc: flag_asynchronous_unwind_tables = 1; On the other side, the @samp{setarch `uname -m` -R ./prog} suggestion is very Linux specific, so if we mention it at all, it should mention that "e.g. on Linux through ..." or something similar. I also wouldn't mention the "and read-only variables" part, that is irrelevant for stack traces. Jakub