diff options
| author | Fangrui Song <i@maskray.me> | 2022-02-09 00:59:53 +0000 |
|---|---|---|
| committer | Ed Maste <emaste@FreeBSD.org> | 2022-02-17 01:03:53 +0000 |
| commit | 31ec0c5834b051a512508ba3291e6b848d4643e5 (patch) | |
| tree | e498aae7e57924fe19e409c5b2b2172109572480 /usr.sbin/crunch/crunchide | |
| parent | 1fa9903bee3b642049d1705a714bd775b7d4e678 (diff) | |
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)
Diffstat (limited to 'usr.sbin/crunch/crunchide')
| -rw-r--r-- | usr.sbin/crunch/crunchide/crunchide.c | 6 |
1 files changed, 2 insertions, 4 deletions
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 |