libtpool: -Wno-clobbered

Also remove -Wno-unused-but-set-variable

Upstream-bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61118
Reviewed-by: Alejandro Colomar <alx.manpages@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13110

9 files changed, 34 insertions, 31 deletions

diff --git a/config/always-compiler-options.m4 b/config/always-compiler-options.m4
index 82b351c6e..4b19b52bd 100644
--- a/config/always-compiler-options.m4
+++ b/config/always-compiler-options.m4
@@ -135,7 +135,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_FORMAT_TRUNCATION], [
 ])
 
 dnl #
-dnl # Check if gcc supports -Wno-format-truncation option.
+dnl # Check if gcc supports -Wno-format-zero-length option.
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_FORMAT_ZERO_LENGTH], [
 	AC_MSG_CHECKING([whether $CC supports -Wno-format-zero-length])
@@ -183,29 +183,29 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_BOOL_COMPARE], [
 ])
 
 dnl #
-dnl # Check if gcc supports -Wno-unused-but-set-variable option.
+dnl # Check if gcc supports -Wno-clobbered option.
 dnl #
-dnl # We actually invoke gcc with the -Wunused-but-set-variable option
+dnl # We actually invoke gcc with the -Wclobbered option
 dnl # and infer the 'no-' version does or doesn't exist based upon
 dnl # the results.  This is required because when checking any of
 dnl # no- prefixed options gcc always returns success.
 dnl #
-AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_UNUSED_BUT_SET_VARIABLE], [
-	AC_MSG_CHECKING([whether $CC supports -Wno-unused-but-set-variable])
+AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_CLOBBERED], [
+	AC_MSG_CHECKING([whether $CC supports -Wno-clobbered])
 
 	saved_flags="$CFLAGS"
-	CFLAGS="$CFLAGS -Werror -Wunused-but-set-variable"
+	CFLAGS="$CFLAGS -Werror -Wclobbered"
 
 	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
-		NO_UNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable
+		NO_CLOBBERED=-Wno-clobbered
 		AC_MSG_RESULT([yes])
 	], [
-		NO_UNUSED_BUT_SET_VARIABLE=
+		NO_CLOBBERED=
 		AC_MSG_RESULT([no])
 	])
 
 	CFLAGS="$saved_flags"
-	AC_SUBST([NO_UNUSED_BUT_SET_VARIABLE])
+	AC_SUBST([NO_CLOBBERED])
 ])
 
 dnl #
diff --git a/config/kernel-blk-queue.m4 b/config/kernel-blk-queue.m4
index ff5d2d370..559ae9800 100644
--- a/config/kernel-blk-queue.m4
+++ b/config/kernel-blk-queue.m4
@@ -215,17 +215,17 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_FLUSH], [
 	ZFS_LINUX_TEST_SRC([blk_queue_flush], [
 		#include <linux/blkdev.h>
 	], [
-		struct request_queue *q = NULL;
+		struct request_queue *q __attribute__ ((unused)) = NULL;
 		(void) blk_queue_flush(q, REQ_FLUSH);
-	], [$NO_UNUSED_BUT_SET_VARIABLE], [ZFS_META_LICENSE])
+	], [], [ZFS_META_LICENSE])
 
 	ZFS_LINUX_TEST_SRC([blk_queue_write_cache], [
 		#include <linux/kernel.h>
 		#include <linux/blkdev.h>
 	], [
-		struct request_queue *q = NULL;
+		struct request_queue *q __attribute__ ((unused)) = NULL;
 		blk_queue_write_cache(q, true, true);
-	], [$NO_UNUSED_BUT_SET_VARIABLE], [ZFS_META_LICENSE])
+	], [], [ZFS_META_LICENSE])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_FLUSH], [
@@ -278,9 +278,9 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_MAX_HW_SECTORS], [
 	ZFS_LINUX_TEST_SRC([blk_queue_max_hw_sectors], [
 		#include <linux/blkdev.h>
 	], [
-		struct request_queue *q = NULL;
+		struct request_queue *q __attribute__ ((unused)) = NULL;
 		(void) blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
-	], [$NO_UNUSED_BUT_SET_VARIABLE])
+	], [])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_MAX_HW_SECTORS], [
@@ -301,9 +301,9 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_MAX_SEGMENTS], [
 	ZFS_LINUX_TEST_SRC([blk_queue_max_segments], [
 		#include <linux/blkdev.h>
 	], [
-		struct request_queue *q = NULL;
+		struct request_queue *q __attribute__ ((unused)) = NULL;
 		(void) blk_queue_max_segments(q, BLK_MAX_SEGMENTS);
-	], [$NO_UNUSED_BUT_SET_VARIABLE])
+	], [])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_MAX_SEGMENTS], [
diff --git a/config/kernel-block-device-operations.m4 b/config/kernel-block-device-operations.m4
index a48618185..84e39dc8a 100644
--- a/config/kernel-block-device-operations.m4
+++ b/config/kernel-block-device-operations.m4
@@ -6,13 +6,16 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS], [
 		#include <linux/blkdev.h>
 
 		unsigned int blk_check_events(struct gendisk *disk,
-		    unsigned int clearing) { return (0); }
+		    unsigned int clearing) {
+			(void) disk, (void) clearing;
+			return (0);
+		}
 
 		static const struct block_device_operations
 		    bops __attribute__ ((unused)) = {
 			.check_events	= blk_check_events,
 		};
-	], [], [$NO_UNUSED_BUT_SET_VARIABLE])
+	], [], [])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS], [
@@ -31,7 +34,10 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID], [
 	ZFS_LINUX_TEST_SRC([block_device_operations_release_void], [
 		#include <linux/blkdev.h>
 
-		void blk_release(struct gendisk *g, fmode_t mode) { return; }
+		void blk_release(struct gendisk *g, fmode_t mode) {
+			(void) g, (void) mode;
+			return;
+		}
 
 		static const struct block_device_operations
 		    bops __attribute__ ((unused)) = {
@@ -40,7 +46,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID], [
 			.ioctl		= NULL,
 			.compat_ioctl	= NULL,
 		};
-	], [], [$NO_UNUSED_BUT_SET_VARIABLE])
+	], [], [])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID], [
@@ -61,6 +67,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLOCK_DEVICE_OPERATIONS_REVALIDATE_DISK], [
 		#include <linux/blkdev.h>
 
 		int blk_revalidate_disk(struct gendisk *disk) {
+			(void) disk;
 			return(0);
 		}
 
@@ -68,7 +75,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLOCK_DEVICE_OPERATIONS_REVALIDATE_DISK], [
 		    bops __attribute__ ((unused)) = {
 			.revalidate_disk	= blk_revalidate_disk,
 		};
-	], [], [$NO_UNUSED_BUT_SET_VARIABLE])
+	], [], [])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLOCK_DEVICE_OPERATIONS_REVALIDATE_DISK], [
diff --git a/config/kernel-get-disk-ro.m4 b/config/kernel-get-disk-ro.m4
index 8a379c766..acfcb69ac 100644
--- a/config/kernel-get-disk-ro.m4
+++ b/config/kernel-get-disk-ro.m4
@@ -5,9 +5,9 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_GET_DISK_RO], [
 	ZFS_LINUX_TEST_SRC([get_disk_ro], [
 		#include <linux/blkdev.h>
 	],[
-		struct gendisk *disk = NULL;
+		struct gendisk *disk __attribute__ ((unused)) = NULL;
 		(void) get_disk_ro(disk);
-	], [$NO_UNUSED_BUT_SET_VARIABLE])
+	], [])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_GET_DISK_RO], [
diff --git a/config/zfs-build.m4 b/config/zfs-build.m4
index d75867c65..f30c2664c 100644
--- a/config/zfs-build.m4
+++ b/config/zfs-build.m4
@@ -209,7 +209,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [
 	AX_COUNT_CPUS([])
 	AC_SUBST(CPU_COUNT)
 
-	ZFS_AC_CONFIG_ALWAYS_CC_NO_UNUSED_BUT_SET_VARIABLE
+	ZFS_AC_CONFIG_ALWAYS_CC_NO_CLOBBERED
 	ZFS_AC_CONFIG_ALWAYS_CC_NO_BOOL_COMPARE
 	ZFS_AC_CONFIG_ALWAYS_CC_IMPLICIT_FALLTHROUGH
 	ZFS_AC_CONFIG_ALWAYS_CC_FRAME_LARGER_THAN
diff --git a/lib/libtpool/Makefile.am b/lib/libtpool/Makefile.am
index 40fd137b4..638d427bd 100644
--- a/lib/libtpool/Makefile.am
+++ b/lib/libtpool/Makefile.am
@@ -1,6 +1,8 @@
 include $(top_srcdir)/config/Rules.am
 
 AM_CFLAGS += -fvisibility=hidden
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61118
+AM_CFLAGS += $(NO_CLOBBERED)
 
 noinst_LTLIBRARIES = libtpool.la
 
diff --git a/lib/libzfs/Makefile.am b/lib/libzfs/Makefile.am
index e23f7c162..0827d52a4 100644
--- a/lib/libzfs/Makefile.am
+++ b/lib/libzfs/Makefile.am
@@ -6,7 +6,6 @@ VPATH = \
 	$(top_srcdir)/lib/libzfs
 
 # Suppress unused but set variable warnings often due to ASSERTs
-AM_CFLAGS += $(NO_UNUSED_BUT_SET_VARIABLE)
 AM_CFLAGS += $(LIBCRYPTO_CFLAGS) $(ZLIB_CFLAGS)
 AM_CFLAGS += -fvisibility=hidden
 
diff --git a/lib/libzpool/Makefile.am b/lib/libzpool/Makefile.am
index e49577ec4..e60a906a5 100644
--- a/lib/libzpool/Makefile.am
+++ b/lib/libzpool/Makefile.am
@@ -17,9 +17,6 @@ endif
 # Unconditionally enable debugging for libzpool
 AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
 
-# Suppress unused but set variable warnings often due to ASSERTs
-AM_CFLAGS += $(NO_UNUSED_BUT_SET_VARIABLE)
-
 # Includes kernel code generate warnings for large stack frames
 AM_CFLAGS += $(FRAME_LARGER_THAN)
 
diff --git a/lib/libzutil/Makefile.am b/lib/libzutil/Makefile.am
index b16325061..4f2dbc62b 100644
--- a/lib/libzutil/Makefile.am
+++ b/lib/libzutil/Makefile.am
@@ -1,7 +1,5 @@
 include $(top_srcdir)/config/Rules.am
 
-# Suppress unused but set variable warnings often due to ASSERTs
-AM_CFLAGS += $(NO_UNUSED_BUT_SET_VARIABLE)
 AM_CFLAGS += $(LIBBLKID_CFLAGS) $(LIBUDEV_CFLAGS)
 AM_CFLAGS += -fvisibility=hidden