https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116614
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-14 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:c9fd43a8df0e30109794e2480e2d8d05d00763c0 commit r14-10665-gc9fd43a8df0e30109794e2480e2d8d05d00763c0 Author: Jakub Jelinek <ja...@redhat.com> Date: Sat Sep 7 09:36:53 2024 +0200 libiberty: Fix up > 64K section handling in simple_object_elf_copy_lto_debug_section [PR116614] cat abc.C #define A(n) struct T##n {} t##n; #define B(n) A(n##0) A(n##1) A(n##2) A(n##3) A(n##4) A(n##5) A(n##6) A(n##7) A(n##8) A(n##9) #define C(n) B(n##0) B(n##1) B(n##2) B(n##3) B(n##4) B(n##5) B(n##6) B(n##7) B(n##8) B(n##9) #define D(n) C(n##0) C(n##1) C(n##2) C(n##3) C(n##4) C(n##5) C(n##6) C(n##7) C(n##8) C(n##9) #define E(n) D(n##0) D(n##1) D(n##2) D(n##3) D(n##4) D(n##5) D(n##6) D(n##7) D(n##8) D(n##9) E(1) E(2) E(3) int main () { return 0; } ./xg++ -B ./ -o abc{.o,.C} -flto -flto-partition=1to1 -O2 -g -fdebug-types-section -c ./xgcc -B ./ -o abc{,.o} -flto -flto-partition=1to1 -O2 (not included in testsuite as it takes a while to compile) FAILs with lto-wrapper: fatal error: Too many copied sections: Operation not supported compilation terminated. /usr/bin/ld: error: lto-wrapper failed collect2: error: ld returned 1 exit status The following patch fixes that. Most of the 64K+ section support for reading and writing was already there years ago (and especially reading used quite often already) and a further bug fixed in it in the PR104617 fix. Yet, the fix isn't solely about removing the if (new_i - 1 >= SHN_LORESERVE) { *err = ENOTSUP; return "Too many copied sections"; } 5 lines, the missing part was that the function only handled reading of the .symtab_shndx section but not copying/updating of it. If the result has less than 64K-epsilon sections, that actually wasn't needed, but e.g. with -fdebug-types-section one can exceed that pretty easily (reported to us on WebKitGtk build on ppc64le). Updating the section is slightly more complicated, because it basically needs to be done in lock step with updating the .symtab section, if one doesn't need to use SHN_XINDEX in there, the section should (or should be updated to) contain SHN_UNDEF entry, otherwise needs to have whatever would be overwise stored but couldn't fit. But repeating due to that all the symtab decisions what to discard and how to rewrite it would be ugly. So, the patch instead emits the .symtab_shndx section (or sections) last and prepares the content during the .symtab processing and in a second pass when going just through .symtab_shndx sections just uses the saved content. 2024-09-07 Jakub Jelinek <ja...@redhat.com> PR lto/116614 * simple-object-elf.c (SHN_COMMON): Align comment with neighbouring comments. (SHN_HIRESERVE): Use uppercase hex digits instead of lowercase for consistency. (simple_object_elf_find_sections): Formatting fixes. (simple_object_elf_fetch_attributes): Likewise. (simple_object_elf_attributes_merge): Likewise. (simple_object_elf_start_write): Likewise. (simple_object_elf_write_ehdr): Likewise. (simple_object_elf_write_shdr): Likewise. (simple_object_elf_write_to_file): Likewise. (simple_object_elf_copy_lto_debug_section): Likewise. Don't fail for new_i - 1 >= SHN_LORESERVE, instead arrange in that case to copy over .symtab_shndx sections, though emit those last and compute their section content when processing associated .symtab sections. Handle simple_object_internal_read failure even in the .symtab_shndx reading case. (cherry picked from commit bb8dd0980b39cfd601f88703fd356055727ef24d)
