On Thu, Mar 4, 2021 at 7:14 PM Timm Bäder <tbae...@redhat.com> wrote: > > On 18/11/2020 06:34, Navin P via Elfutils-devel wrote: > >>> diff --git a/src/elflint.c b/src/elflint.c > >>> index ef3e3732..62663800 100644 > >>> --- a/src/elflint.c > >>> +++ b/src/elflint.c > >>> @@ -3905,6 +3905,7 @@ section [%2zu] '%s': size not multiple of entry > >>> size\n"), > >>> && shdr->sh_type != SHT_GNU_ATTRIBUTES > >>> && shdr->sh_type != SHT_GNU_LIBLIST > >>> && shdr->sh_type != SHT_CHECKSUM > >>> + && shdr->sh_type != SHT_LLVM_ADDRSIG > >>> && shdr->sh_type != SHT_GNU_verdef > >>> && shdr->sh_type != SHT_GNU_verneed > >>> && shdr->sh_type != SHT_GNU_versym > >> > >> Note that for various of these SHT_GNU extensions we actually do have > >> some extra checks. Do we need to check anything for a section marked > >> SHT_LLVM_ADDRSIG? > >> > > We can do two things here > > a) Recognize the section exists but ignore its contents which is what i > > do. This needn't be the correct approach. > > You may need to check the contents to sht_llvm_addrsig but that is > > lot of work after the format has been frozen. > > https://www.mail-archive.com/netdev@vger.kernel.org/msg348254.html > > readelf output > > [22] .llvm_addrsig LOOS+0xfff4c03 0000000000000000 ... > > > > b) If we don't want to recognize SHT_LLVM_ADDRSIG > > you can strip section from object file by objcopy -R .llvm_addrsig size.o > > conditionally based on clang compiler. > > > > Hey Navin and Mark, > > any update on this? I see that SHT_LLVM_ADDRSIG is still not in upstream > glibc. Are you working on that, Navin? > > As for the checks, I'm not sure we can do anything here since elfutils > can't know whether a symbol is rightfully marked as address-significant. >
clang has a flag -fno-addrsig that doesn't generate the addrsig section. https://releases.llvm.org/7.0.0/tools/clang/docs/ClangCommandLineReference.html#cmdoption-clang-faddrsig So adding that for option for only clang should work. I remember I ran the tests and it worked. But you should check again. As far as i remember this should complete the changes Here is a small example navin@mint-Aspire:~/c$ cat tmp.c int main() { return 0 ; } navin@mint-Aspire:~/c$ clang tmp.c -c navin@mint-Aspire:~/c$ readelf -a tmp.o | grep -i addrsig [ 7] .llvm_addrsig LOOS+0xfff4c03 0000000000000000 00000120 navin@mint-Aspire:~/c$ clang tmp.c -c -fno-addrsig navin@mint-Aspire:~/c$ readelf -a tmp.o | grep -i addrsig navin@mint-Aspire:~/c$
