On Tue, Nov 15, 2022 at 06:43:59AM +0900, Akira Yokosawa wrote: > An item on GCC 10 changes [1] reads: > > - GCC now defaults to -fno-common. As a result, global variable > accesses are more efficient on various targets. In C, global > variables with multiple tentative definitions now result in > linker errors. With -fcommon such definitions are silently > merged during linking. > > This change affects builds under CodeSamples/ as reported by Elad [2]. > > As a band-aide fix, add -fcommon to GCC_ARGS where necessary. > > Reported-by: Elad Lahav <e2lahav@xxxxxxxxx> > Link: [1] https://gcc.gnu.org/gcc-10/changes.html > Link: [2] https://www.spinics.net/lists/perfbook/msg03690.html > Signed-off-by: Akira Yokosawa <akiyks@xxxxxxxxx> Queued, thank you both! Thanx, Paul > --- > v2: > - Fix mismatch of From: and S-o-b. > > Thanks, Akira > > -- > CodeSamples/datastruct/Issaquah/Makefile | 2 ++ > CodeSamples/datastruct/hash/Makefile | 2 ++ > CodeSamples/defer/Makefile | 2 ++ > 3 files changed, 6 insertions(+) > > diff --git a/CodeSamples/datastruct/Issaquah/Makefile b/CodeSamples/datastruct/Issaquah/Makefile > index 51b91fd8dafa..c3b724d750b2 100644 > --- a/CodeSamples/datastruct/Issaquah/Makefile > +++ b/CodeSamples/datastruct/Issaquah/Makefile > @@ -32,6 +32,8 @@ endif > > include $(top)/recipes.mk > > +GCC_ARGS += -fcommon > + > # NOTE: For decent scalability on update-side tests as of early 2015, > # use something like jemalloc() instead of glibc malloc(). > # If you install jemalloc at /home/paulmck/jemalloc, you will > diff --git a/CodeSamples/datastruct/hash/Makefile b/CodeSamples/datastruct/hash/Makefile > index 80568cd11981..a56255a272eb 100644 > --- a/CodeSamples/datastruct/hash/Makefile > +++ b/CodeSamples/datastruct/hash/Makefile > @@ -32,6 +32,8 @@ endif > > include $(top)/recipes.mk > > +GCC_ARGS += -fcommon > + > hash_bkt: hash_bkt.c ../../api.h hashtorture.h > cc $(GCC_ARGS) -DTEST_HASH -o hash_bkt hash_bkt.c $(LIB)/random.c -lpthread > > diff --git a/CodeSamples/defer/Makefile b/CodeSamples/defer/Makefile > index 46cb87a1c9dc..3cf3e5a5f134 100644 > --- a/CodeSamples/defer/Makefile > +++ b/CodeSamples/defer/Makefile > @@ -61,6 +61,8 @@ endif > > include $(top)/recipes.mk > > +GCC_ARGS += -fcommon > + > # Note that bug_srcu_a is disabled until completed. > bug_srcu_a: bug_srcu_a.c srcu.c ../api.h > cc $(GCC_ARGS) -o bug_srcu_a -DTEST bug_srcu_a.c -lurcu -lpthread > > base-commit: 7f7a2c25e3d2e87412d10bdb355b369eca524b1a > -- > 2.25.1 > >
