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The discussion on gdb-patches which led to this patch may be found here: https://www.sourceware.org/ml/gdb-patches/2019-05/msg00018.html Here's a brief synopsis/analysis: Eli Zaretskii, while debugging a Windows emacs executable, found that functions comprised of more than one (non-contiguous) address range were not being displayed correctly in a backtrace. This is the example that Eli provided: (gdb) bt #0 0x76a63227 in KERNELBASE!DebugBreak () from C:\Windows\syswow64\KernelBase.dll #1 0x012e7b89 in emacs_abort () at w32fns.c:10768 #2 0x012e1f3b in print_vectorlike.cold () at print.c:1824 #3 0x011d2dec in print_object (obj=<optimized out>, printcharfun=XIL(0), escapeflag=true) at print.c:2150 The function print_vectorlike consists of two address ranges, one of which contains "cold" code which is expected to not execute very often. There is a minimal symbol, print_vectorlike.cold.65, which is the address of the "cold" range. GDB is prefering this minsym over the the name provided by the DWARF info due to some really old code in GDB which handles "certain pathological cases". This comment reads as follows: /* In certain pathological cases, the symtabs give the wrong function (when we are in the first function in a file which is compiled without debugging symbols, the previous function is compiled with debugging symbols, and the "foo.o" symbol that is supposed to tell us where the file with debugging symbols ends has been truncated by ar because it is longer than 15 characters). This also occurs if the user uses asm() to create a function but not stabs for it (in a file compiled with -g). So look in the minimal symbol tables as well, and if it comes up with a larger address for the function use that instead. I don't think this can ever cause any problems; there shouldn't be any minimal symbols in the middle of a function; if this is ever changed many parts of GDB will need to be changed (and we'll create a find_pc_minimal_function or some such). */ In an earlier version of this patch, I had left the code for the pathological case intact, but those who reviwed that patch recommended removing it. So that's what I've done - I've removed it. gdb/ChangeLog: * stack.c (find_frame_funname): Remove code which preferred minsym over symtab sym in "certain pathological cases".
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.