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* [Bug lto/105877] New: GNU strip breaks -flto -g .o files @ 2022-06-07 18:42 slyfox at gcc dot gnu.org 2022-06-07 19:08 ` [Bug lto/105877] " hjl.tools at gmail dot com ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: slyfox at gcc dot gnu.org @ 2022-06-07 18:42 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105877 Bug ID: 105877 Summary: GNU strip breaks -flto -g .o files Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: lto Assignee: unassigned at gcc dot gnu.org Reporter: slyfox at gcc dot gnu.org CC: hjl.tools at gmail dot com, hubicka at gcc dot gnu.org, marxin at gcc dot gnu.org Target Milestone: --- Host: x86_64-unknown-linux-gnu Initially reported by drnfc on https://github.com/trofi/nix-guix-gentoo/issues/19 where gcc failed to link nix-2.9.0 against stripped liblowdown.a. Both are built with -flto. I'm not sure if it's a strip bug, gcc bug or both. I think (did not check) it used to work long ago. I'm leaning towards gcc bug and filing it here first. Here is a minimal reproducer: // $ cat document.c void lowdown_doc_new(void) {} // $ cat markdown.cc extern "C" { void lowdown_doc_new(void); } int main(){ lowdown_doc_new(); } $ gcc -flto -g -c -o document.o document.c $ cp document.o document-stripped.o $ strip -g document-stripped.o $ g++ markdown.cc -o a document.o -flto-partition=max -flto -g $ g++ markdown.cc -o a document-stripped.o -flto-partition=max -flto -g ld: /tmp/ccajK6YG.ltrans0.ltrans.o:(.debug_info+0x2f): undefined reference to `document.c.20ce96f1' $ gcc -v |& unnix Using built-in specs. COLLECT_GCC=/<<NIX>>/gcc-13.0.0/bin/gcc COLLECT_LTO_WRAPPER=/<<NIX>>/gcc-13.0.0/libexec/gcc/x86_64-unknown-linux-gnu/13.0.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: Thread model: posix Supported LTO compression algorithms: zlib gcc version 13.0.0 20220605 (experimental) (GCC) ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug lto/105877] GNU strip breaks -flto -g .o files 2022-06-07 18:42 [Bug lto/105877] New: GNU strip breaks -flto -g .o files slyfox at gcc dot gnu.org @ 2022-06-07 19:08 ` hjl.tools at gmail dot com 2022-06-09 10:14 ` hubicka at kam dot mff.cuni.cz ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: hjl.tools at gmail dot com @ 2022-06-07 19:08 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105877 --- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> --- "strip -g" removed .gnu.debuglto_.debug_info sections. Should LTO remove the references of stripped debug info? Or should "strip -g" keep LTO debug info? ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug lto/105877] GNU strip breaks -flto -g .o files 2022-06-07 18:42 [Bug lto/105877] New: GNU strip breaks -flto -g .o files slyfox at gcc dot gnu.org 2022-06-07 19:08 ` [Bug lto/105877] " hjl.tools at gmail dot com @ 2022-06-09 10:14 ` hubicka at kam dot mff.cuni.cz 2022-06-13 13:07 ` rguenth at gcc dot gnu.org 2022-06-16 13:27 ` marxin at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: hubicka at kam dot mff.cuni.cz @ 2022-06-09 10:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105877 --- Comment #2 from hubicka at kam dot mff.cuni.cz --- > "strip -g" removed .gnu.debuglto_.debug_info sections. Should LTO remove the > references of stripped debug info? Or should "strip -g" keep LTO debug info? I suppose we should try to immitate what happens without -flto, so probably check for the presence of debuglto sections and avoid producing debug info when they have been stripped? I am not sure how hard would be to implement this especially in situations where part of object files were stripped and others not? ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug lto/105877] GNU strip breaks -flto -g .o files 2022-06-07 18:42 [Bug lto/105877] New: GNU strip breaks -flto -g .o files slyfox at gcc dot gnu.org 2022-06-07 19:08 ` [Bug lto/105877] " hjl.tools at gmail dot com 2022-06-09 10:14 ` hubicka at kam dot mff.cuni.cz @ 2022-06-13 13:07 ` rguenth at gcc dot gnu.org 2022-06-16 13:27 ` marxin at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2022-06-13 13:07 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105877 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rguenth at gcc dot gnu.org --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to hubicka from comment #2) > > "strip -g" removed .gnu.debuglto_.debug_info sections. Should LTO remove the > > references of stripped debug info? Or should "strip -g" keep LTO debug info? > > I suppose we should try to immitate what happens without -flto, so > probably check for the presence of debuglto sections and avoid producing > debug info when they have been stripped? > I am not sure how hard would be to implement this especially in > situations where part of object files were stripped and others not? I think it might be possible to detect whether the compiled objects are stripped and then avoid streaming references to its debug sections by magically turning it to -g0. But not sure how awkward this will be. Not sure why strip now strips .gnu.debuglto_.debug_info, it didn't do that before. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug lto/105877] GNU strip breaks -flto -g .o files 2022-06-07 18:42 [Bug lto/105877] New: GNU strip breaks -flto -g .o files slyfox at gcc dot gnu.org ` (2 preceding siblings ...) 2022-06-13 13:07 ` rguenth at gcc dot gnu.org @ 2022-06-16 13:27 ` marxin at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: marxin at gcc dot gnu.org @ 2022-06-16 13:27 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105877 Martin Liška <marxin at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Last reconfirmed| |2022-06-16 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-06-16 13:27 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-06-07 18:42 [Bug lto/105877] New: GNU strip breaks -flto -g .o files slyfox at gcc dot gnu.org 2022-06-07 19:08 ` [Bug lto/105877] " hjl.tools at gmail dot com 2022-06-09 10:14 ` hubicka at kam dot mff.cuni.cz 2022-06-13 13:07 ` rguenth at gcc dot gnu.org 2022-06-16 13:27 ` marxin at gcc dot gnu.org
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