The branch main has been updated by emaste:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ec81497cc7260b26c2af615c54aa80f515d6c539
commit ec81497cc7260b26c2af615c54aa80f515d6c539
Author: Fangrui Song <i...@maskray.me>
AuthorDate: 2022-02-09 00:59:53 +0000
Commit: Ed Maste <ema...@freebsd.org>
CommitDate: 2022-02-09 18:54:35 +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
---
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 89d549b18b4e..63ce727496b7 100644
--- a/usr.sbin/crunch/crunchgen/crunchgen.c
+++ b/usr.sbin/crunch/crunchgen/crunchgen.c
@@ -1123,7 +1123,7 @@ 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
