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>
---
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
