Hi Thomas, Masahiro, +Cc Peter Oberparleiter, MPTCP ML On 15/03/2025 14:20, Thomas Weißschuh wrote: > -fmacro-prefix-map only affects __FILE__ and __BASE_FILE__. > Other references, for example in debug information, are not affected. > This makes handling of file references in the compiler outputs harder to > use and creates problems for reproducible builds. > > Switch to -ffile-prefix map which affects all references. > > Also drop the documentation section advising manual specification of > -fdebug-prefix-map for reproducible builds, as it is not necessary > anymore. > > Suggested-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> > Link: https://lore.kernel.org/lkml/c49cc967294f9a3a4a34f69b6a8727a6d3959ed8.camel@xxxxxxxxxxxxxxx/ > Acked-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> # arch/x86/ > Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> Thank you for having worked on that! (...) > diff --git a/Makefile b/Makefile > index 5c333682dc9142b1aacfe454a5c77f5923554b7d..4f920187cee658ae4d1b807fca365f6994274828 100644 > --- a/Makefile > +++ b/Makefile > @@ -1067,7 +1067,7 @@ endif > > # change __FILE__ to the relative path to the source directory > ifdef building_out_of_srctree > -KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=) > +KBUILD_CPPFLAGS += $(call cc-option,-ffile-prefix-map=$(srcroot)/=) > KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/= > endif Today, I noticed that my CI for the MPTCP subsystem couldn't produce code coverage files like before: the source files are not found. A 'git bisect' pointed me to this patch. Reverting it seems to fix the issue. My CI is building the kernel out of the source tree, in ".virtme/build". Before and after this patch, GCOV seems to do its job properly. Capturing GCOV data with this lcov command seems OK too: lcov --capture --keep-going -j "${INPUT_CPUS}" \ --rc geninfo_unexecuted_blocks=1 \ --include '/net/mptcp/' \ --function-coverage --branch-coverage \ -b "${PWD}/.virtme/build" -o kernel.lcov But after this patch, lcov complains some files are not found, e.g. ERROR: (source) unable to open ${WORKDIR}/.virtme/build/net/mptcp/ctrl.c: No such file or directory The output file is different: the path to the source file is wrong because it points to the build dir. Instead of ... SF:${WORKDIR}/net/mptcp/ctrl.c ... now I have ... SF:${WORKDIR}/.virtme/build/net/mptcp/ctrl.c Are there modifications needed on GCOV side to adapt to the behaviour change introduced by this patch? Or something else needed on the userspace side? Cheers, Matt -- Sponsored by the NGI0 Core fund.
