Created attachment 1344519 [details] split-dwarf.tar.gz Steps to reproduce on rhel6: $ scl enable devtoolset-6 bash $ make CXXFLAGS="-fuse-ld=gold -gsplit-dwarf -Wl,--gdb-index" clean all $ gdb exec/simple-calls.noopt << see gdb-transcript for extra steps in gdb, basically, it should show listing of ../libsrc/foo-bar.C but fails >> This issue does not happen on Fedora with: $ rpm -q gdb gdb-8.0.1-26.fc26.x86_64 *but* if rebuilding plain gdb-8.0.1 from git://sourceware.org/git/binutils-gdb.git, the issue still happens. Might be some Red Hat patch, but comparing sources after all patches, and checking diffs for the gdb/dwarf*.c files does not show anything clear as root cause of the problem. On Fedora 26 run: $ make CXX=g++ CXXFLAGS="-fuse-ld=gold -gsplit-dwarf -Wl,--gdb-index" clean all On rhel6 please make sure to use the devtoolset-6-gdb. The system gdb will happen to work, but it is ignoring the .dwo files. [pcpa@rhel6 split-dwarf]$ which gdb /opt/rh/devtoolset-6/root/usr/bin/gdb [pcpa@rhel6 split-dwarf]$ rpm -qf $(which gdb) devtoolset-6-gdb-7.12.1-47.el6.x86_64 Running gdb under gdb, in the environment the test case works (f26), the openp of the source file shows this: """ Thread 1 "gdb" hit Breakpoint 1, openp (path=path@entry=0x7fffffffd540 "/home/pcpa/sfdc/01959158/split-dwarf/libobj:$cwd", opts=opts@entry=6, string=string@entry=0x555556a25790 "../libsrc/foo-bar.C", mode=mode@entry=0, filename_opened=filename_opened@entry=0x555556ab6228) at ../../gdb/source.c:758 758 { (gdb) bt #0 openp (path=path@entry=0x7fffffffd540 "/home/pcpa/sfdc/01959158/split-dwarf/libobj:$cwd", opts=opts@entry=6, string=string@entry=0x555556a25790 "../libsrc/foo-bar.C", mode=mode@entry=0, filename_opened=filename_opened@entry=0x555556ab6228) at ../../gdb/source.c:758 #1 0x000055555593d120 in find_and_open_source (filename=0x555556a25790 "../libsrc/foo-bar.C", dirname=<optimized out>, fullname=fullname@entry=0x555556ab6228) at ../../gdb/source.c:1120 #2 0x000055555593d694 in open_source_file (s=0x555556ab61f0) at ../../gdb/source.c:1146 #3 print_source_lines_base (s=0x555556ab61f0, line=25, stopline=26, flags=...) at ../../gdb/source.c:1374 #4 0x000055555593e614 in print_source_lines (s=<optimized out>, line=<optimized out>, stopline=<optimized out>, flags=...) at ../../gdb/source.c:1510 #5 0x0000555555947e66 in print_frame_info (frame=frame@entry=0x5555562db690, print_level=print_level@entry=0, print_what=print_what@entry=SRC_AND_LOC, print_args=print_args@entry=1, set_current_sal=set_current_sal@entry=1) at ../../gdb/stack.c:918 #6 0x0000555555947f56 in print_stack_frame (frame=0x5555562db690, print_level=0, print_what=SRC_AND_LOC, set_current_sal=1) at ../../gdb/stack.c:175 #7 0x00005555558d448f in print_stop_location (ws=<synthetic pointer>) at ../../gdb/infrun.c:8107 #8 print_stop_event (uiout=0x5555569e6fb0) at ../../gdb/infrun.c:8124 #9 0x000055555577eaea in tui_on_normal_stop (bs=<optimized out>, print_frame=<optimized out>) at ../../gdb/tui/tui-interp.c:99 #10 0x000055555590695d in generic_observer_notify (args=0x7fffffffd8f0, subject=<optimized out>) at ../../gdb/observer.c:167 #11 observer_notify_normal_stop (bs=<optimized out>, print_frame=print_frame@entry=1) at ./observer.inc:61 #12 0x00005555558d49d3 in normal_stop () at ../../gdb/infrun.c:8398 #13 0x00005555558dd785 in fetch_inferior_event (client_data=<optimized out>) at ../../gdb/infrun.c:3986 #14 0x000055555589843d in gdb_wait_for_event (block=block@entry=0) at ../../gdb/event-loop.c:859 #15 0x000055555589862f in gdb_do_one_event () at ../../gdb/event-loop.c:322 #16 0x000055555589871e in gdb_do_one_event () at ../../gdb/event-loop.c:304 #17 start_event_loop () at ../../gdb/event-loop.c:371 #18 0x00005555558f1138 in captured_command_loop (data=data@entry=0x0) at ../../gdb/main.c:326 #19 0x000055555589a8e3 in catch_errors (func=func@entry=0x5555558f1110 <captured_command_loop(void*)>, func_args=func_args@entry=0x0, errstring=errstring@entry=0x555555b1c792 "", mask=mask@entry=RETURN_MASK_ALL) at ../../gdb/exceptions.c:236 #20 0x00005555558f2476 in captured_main (data=0x7fffffffdd30) at ../../gdb/main.c:1246 #21 gdb_main (args=0x7fffffffdd30) at ../../gdb/main.c:1257 #22 0x000055555565f72b in main (argc=<optimized out>, argv=<optimized out>) at ../../gdb/gdb.c:40 (gdb) frame 2 #2 0x000055555593d694 in open_source_file (s=0x555556ab61f0) at ../../gdb/source.c:1146 1146 return find_and_open_source (s->filename, SYMTAB_DIRNAME (s), &s->fullname); (gdb) p s $1 = (symtab *) 0x555556ab61f0 (gdb) p *s $2 = {next = 0x555556ab6170, compunit_symtab = 0x555556ab60f0, linetable = 0x5555570dc5e0, filename = 0x555556a25790 "../libsrc/foo-bar.C", nlines = 0, line_charpos = 0x0, language = language_cplus, fullname = 0x0} (gdb) p *s.compunit_symtab $3 = {next = 0x555556a54e30, objfile = 0x55555634b9c0, name = 0x555556ab6160 "foo-bar.C", filetabs = 0x555556ab61f0, last_filetab = 0x555556ec0240, debugformat = 0x555555b83af3 "DWARF 2", producer = 0x555556e8e5b8 "GNU C++14 7.2.1 20170915 (Red Hat 7.2.1-2) -mtune=generic -march=x86-64 -gsplit-dwarf -fuse-ld=gold", dirname = 0x5555570dc7e0 "/home/pcpa/sfdc/01959158/split-dwarf/libobj", blockvector = 0x5555570dc2a0, block_line_section = 12, locations_valid = 0, epilogue_unwind_valid = 1, call_site_htab = 0x0, macro_table = 0x0, includes = 0x0, user = 0x0} """ And when it fails: """ Breakpoint 1, openp (path=0x13c2af0 ".:/usr/lib/debug", opts=4, string=0x151f400 "/home/pcpa/split-dwarf/libobj/foo-bar.noopt.dwo", mode=0, filename_opened=0x7fffffffd3a8) at ../../gdb/source.c:757 757 { (gdb) c Continuing. foo (din=4) at ../libsrc/foo-bar.C:25 Breakpoint 1, openp (path=0xfe1440 "$cdir:$cwd", opts=6, string=0x1254930 "../libsrc/foo-bar.C", mode=0, filename_opened=0x13903e8) at ../../gdb/source.c:757 757 { (gdb) bt #0 openp (path=0xfe1440 "$cdir:$cwd", opts=6, string=0x1254930 "../libsrc/foo-bar.C", mode=0, filename_opened=0x13903e8) at ../../gdb/source.c:757 #1 0x0000000000599dd3 in find_and_open_source (filename=0x1254930 "../libsrc/foo-bar.C", dirname=<optimized out>, fullname=0x13903e8) at ../../gdb/source.c:1120 #2 0x000000000059a2f7 in print_source_lines_base (s=0x13903b0, line=25, stopline=26, flags=...) at ../../gdb/source.c:1373 #3 0x000000000059a741 in print_source_lines (s=<optimized out>, line=<optimized out>, stopline=<optimized out>, flags=...) at ../../gdb/source.c:1512 #4 0x00000000005f5a50 in print_frame_info (frame=0x10185c0, print_level=<optimized out>, print_what=<optimized out>, print_args=-1, set_current_sal=1) at ../../gdb/stack.c:935 #5 0x00000000005f60fb in print_stack_frame (frame=0x10185c0, print_level=0, print_what=SRC_AND_LOC, set_current_sal=1) at ../../gdb/stack.c:182 #6 0x00000000005e6071 in print_stop_location (ws=0x7fffffffdbf0) at ../../gdb/infrun.c:8117 #7 print_stop_event (uiout=0x10ef550) at ../../gdb/infrun.c:8135 #8 0x000000000051cedf in tui_on_normal_stop (bs=<optimized out>, print_frame=<optimized out>) at ../../gdb/tui/tui-interp.c:89 #9 0x0000000000646995 in generic_observer_notify (subject=<optimized out>, args=0x7fffffffdc90) at ../../gdb/observer.c:167 #10 0x00000000006479db in observer_notify_normal_stop (bs=<optimized out>, print_frame=<optimized out>) at ./observer.inc:61 #11 0x00000000005e5dd1 in normal_stop () at ../../gdb/infrun.c:8412 #12 0x00000000005eed4d in fetch_inferior_event (client_data=<optimized out>) at ../../gdb/infrun.c:4021 #13 0x0000000000605a08 in gdb_wait_for_event (block=<optimized out>) at ../../gdb/event-loop.c:859 #14 0x0000000000605b78 in gdb_do_one_event () at ../../gdb/event-loop.c:322 #15 0x0000000000605c7f in start_event_loop () at ../../gdb/event-loop.c:371 #16 0x00000000005fe9f8 in captured_command_loop (data=<optimized out>) at ../../gdb/main.c:325 #17 0x00000000005fb805 in catch_errors (func=0x5fe9d0 <captured_command_loop(void*)>, func_args=0x0, errstring=0x8ac0a6 "", mask=RETURN_MASK_ALL) at ../../gdb/exceptions.c:236 #18 0x00000000005ffeee in captured_main (data=<optimized out>) at ../../gdb/main.c:1246 #19 gdb_main (args=<optimized out>) at ../../gdb/main.c:1257 #20 0x000000000040a1e5 in main (argc=<optimized out>, argv=<optimized out>) at ../../gdb/gdb.c:40 (gdb) frame 2 #2 0x000000000059a2f7 in print_source_lines_base (s=0x13903b0, line=25, stopline=26, flags=...) at ../../gdb/source.c:1373 1373 desc = open_source_file (s); (gdb) p s $1 = (symtab *) 0x13903b0 (gdb) p* s $2 = {next = 0x13903f0, compunit_symtab = 0x13902b0, linetable = 0x1c92a90, filename = 0x1254930 "../libsrc/foo-bar.C", nlines = 0, line_charpos = 0x0, language = language_cplus, fullname = 0x0} (gdb) p* s.compunit_symtab $3 = {next = 0x1199760, objfile = 0x11701f0, name = 0x1390320 "<unknown>", filetabs = 0x1c92df0, last_filetab = 0x1c92df0, debugformat = 0x945c15 "DWARF 2", producer = 0x0, dirname = 0x0, blockvector = 0x1c92890, block_line_section = 12, locations_valid = 0, epilogue_unwind_valid = 0, call_site_htab = 0x0, macro_table = 0x0, includes = 0x0, user = 0x0} """
It is already fixed in DTS-7.0: Bug 1482892: https://src.fedoraproject.org/rpms/gdb/c/99b34dc7843b09667bc4cc8e81ed6934d683ef09 https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=16eb6b2db49e6cf2fdca56efd37689fcc170cd37 [PATCH] Fix dwarf2_string_attr for -gsplit-dwarf https://sourceware.org/ml/gdb-patches/2017-10/msg00763.html *** This bug has been marked as a duplicate of bug 1482892 ***
Created attachment 1345667 [details] gdb-7.12.1-sfdc01959158.patch This patch works for the test case and the devtoolset-6. Adding the extra test for DW_FORM_line_strp is not required for the test case and/or devtoolset-6, and adding it would require a significantly large backport.
Is this a request for Brew build of devtoolset-6-gdb?
For the moment the patch was added mostly for documentation. It works for the test case. I am waiting feedback from the user, to know if it works for their needs, as the test case may not cover all usages.
Customer confirms test patch successfully addresses the problem.
Can an official build be done with the proposed patch? The customer is happy with the patch, and from what they could test, it is fully functional with their DTS-6-produced -gsplit-dwarf executables. But their IT is hesitating to install an unofficial, unsupported, patch globally to their developers.
Reproduced against devtoolset-6-gdb-7.12.1-47.el6 and verified against devtoolset-6-gdb-7.12.1-48.el6.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2017:3250