On 8/12/19 11:45 AM, Richard Biener wrote: > On Fri, Aug 9, 2019 at 3:57 PM Martin Liška <mli...@suse.cz> wrote: >> >> Hi. >> >> The patch is about prevention of LTO section name clashing. >> Now we have a situation where body of 2 functions is streamed >> into the same ELF section. Then we'll end up with smashed data. >> >> Patch can bootstrap on x86_64-linux-gnu and survives regression tests. >> >> Ready to be installed? > > I think the comment should mention why we skip a leading '*' > at all.
git blame helps us here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42531 > IIRC this is some target mangling applied to DECL_ASSEMBLER_NAME? Yes, it's prepended here: set_user_assembler_name > And section names cannot contain '*'? As seen in the PR, not. > Or do we need to actually > indentify '*fn' and 'fn' as the same? No, they should be identified as different symbols. > For the testcase what is the clashing > symbol? void __open_alias(int, ...) __asm__("open"); - aka *open and: +extern __inline __attribute__((__gnu_inline__)) int open() {} > Can't we have many so that using "0" always is broken as well? If I'll define 2 symbols that alias to a same asm name, I'll get: $ cat clash.c void __open_alias(int, ...) __asm__("open"); void __open_alias2(int, ...) __asm__("open"); void __open_alias(int flags, ...) {} void __open_alias2(int flags, ...) {} extern __inline __attribute__((__gnu_inline__)) int open() {} struct { void *func; } a = {open}; int main() { return 0; } $ gcc clash.c -flto lto1: fatal error: missing resolution data for *open compilation terminated. Which is a reasonable error message to me. Martin > > Richard. > >> Thanks, >> Martin >> >> gcc/ChangeLog: >> >> 2019-08-09 Martin Liska <mli...@suse.cz> >> >> PR lto/91393 >> PR lto/88220 >> * lto-streamer.c (lto_get_section_name): Replace '*' leading >> character with '0'. >> >> gcc/testsuite/ChangeLog: >> >> 2019-08-09 Martin Liska <mli...@suse.cz> >> >> PR lto/91393 >> PR lto/88220 >> * gcc.dg/lto/pr91393_0.c: New test. >> --- >> gcc/lto-streamer.c | 15 ++++++++++++--- >> gcc/testsuite/gcc.dg/lto/pr91393_0.c | 11 +++++++++++ >> 2 files changed, 23 insertions(+), 3 deletions(-) >> create mode 100644 gcc/testsuite/gcc.dg/lto/pr91393_0.c >> >>
