Date: Thu, 17 Feb 2022 01:13:36 GMT From: Ed Maste <emaste@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 31ec0c5834b0 - stable/13 - crunchgen: remove -dc from linker invocation Message-ID: <202202170113.21H1DaYc042346@gitrepo.freebsd.org>
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The branch stable/13 has been updated by emaste: URL: https://cgit.FreeBSD.org/src/commit/?id=31ec0c5834b051a512508ba3291e6b848d4643e5 commit 31ec0c5834b051a512508ba3291e6b848d4643e5 Author: Fangrui Song <i@maskray.me> AuthorDate: 2022-02-09 00:59:53 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2022-02-17 01:03:53 +0000 crunchgen: remove -dc from linker invocation In GNU ld and ld.lld, -dc is used with -r to allocate space to COMMON symbols. It is presumably to work around legacy code which cannot handle COMMON symbols in relocatable output. ld.lld may remove -dc or make it a no-op for the 15.0.0 release. As of 7420b323a014 crunch/crunchide does not require -dc, as the symbol hiding technique no longer relied on making symbols local. In addition -fno-common is now the default in Clang and GCC, so -dc serves no purpose as the compiler does not generate COMMON symbols anyway. See https://maskray.me/blog/2022-02-06-all-about-common-symbols for more detail on common symbols. Reviewed by: emaste MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D34215 (cherry picked from commit ec81497cc7260b26c2af615c54aa80f515d6c539) --- usr.sbin/crunch/crunchgen/crunchgen.c | 2 +- usr.sbin/crunch/crunchide/crunchide.c | 6 ++---- 2 files changed, 3 insertions(+), 5 deletions(-) diff --git a/usr.sbin/crunch/crunchgen/crunchgen.c b/usr.sbin/crunch/crunchgen/crunchgen.c index 94792c5ec50b..9d603abc9114 100644 --- a/usr.sbin/crunch/crunchgen/crunchgen.c +++ b/usr.sbin/crunch/crunchgen/crunchgen.c @@ -1137,7 +1137,7 @@ prog_makefile_rules(FILE *outmk, prog_t *p) fprintf(outmk, " $(%s_LIBS)", p->ident); fprintf(outmk, "\n"); - fprintf(outmk, "\t$(CC) -nostdlib -Wl,-dc -r -o %s.lo %s_stub.o $(%s_OBJPATHS)", + fprintf(outmk, "\t$(CC) -nostdlib -r -o %s.lo %s_stub.o $(%s_OBJPATHS)", p->name, p->name, p->ident); if (p->libs) fprintf(outmk, " $(%s_LIBS)", p->ident); diff --git a/usr.sbin/crunch/crunchide/crunchide.c b/usr.sbin/crunch/crunchide/crunchide.c index 1f2f98893bac..bd663e1d57bd 100644 --- a/usr.sbin/crunch/crunchide/crunchide.c +++ b/usr.sbin/crunch/crunchide/crunchide.c @@ -28,9 +28,7 @@ /* * crunchide.c - tiptoes through a symbol table, hiding all defined * global symbols. Allows the user to supply a "keep list" of symbols - * that are not to be hidden. This program relies on the use of the - * linker's -dc flag to actually put global bss data into the file's - * bss segment (rather than leaving it as undefined "common" data). + * that are not to be hidden. * * The point of all this is to allow multiple programs to be linked * together without getting multiple-defined errors. @@ -40,7 +38,7 @@ * int foo_main(int argc, char **argv){ return main(argc, argv); } * like so: * cc -c foo.c foostub.c - * ld -dc -r foo.o foostub.o -o foo.combined.o + * ld -r foo.o foostub.o -o foo.combined.o * crunchide -k _foo_main foo.combined.o * at this point, foo.combined.o can be linked with another program * and invoked with "foo_main(argc, argv)". foo's main() and any
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