The "-Wimplicit-fallthrough=2" option was introduced into gcc 7.0, it was
enabled when the cross compiler gcc is greater than 7.0, but for the host
side buildtools/pmdinfogen, if the native is older than 7.0, it should not
be enabled.
The fix is to differentiate the host gcc Werror options from the cross gcc.
gcc -Wp,-MD,./.pmdinfogen.o.d.tmp -W -Wall -Wstrict-prototypes
-Wmissing-prototypes -Wmissing-declarations -Wold-style-definition
-Wpointer-arith -Wcast-align -Wnested-externs -Wcast-qual
-Wformat-nonliteral -Wformat-security -Wundef -Wwrite-strings -Wdeprecated
-Werror -Wimplicit-fallthrough=2 -Dbbb -Wno-format-truncation -g
-I/home/gavin/arm_repo/dpdk/build/include -o pmdinfogen.o -c
~/dpdk/buildtools/pmdinfogen/pmdinfogen.c gcc: error:
unrecognized command line option ‘-Wimplicit-fallthrough=2’
~/dpdk/mk/internal/rte.compile-pre.mk:114: recipe for target 'pmdinfogen.o'
failed make[3]: *** [pmdinfogen.o] Error 1
Fixes: ced3e6f8 ("mk: adjust gcc flags for new gcc 7 warnings")
Cc: sta...@dpdk.org
Signed-off-by: Gavin Hu <gavin...@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Reviewed-by: Steve Capper <steve.cap...@arm.com>
Reviewed-by: Thomas Monjalon <tho...@monjalon.net>
---
buildtools/pmdinfogen/Makefile | 2 +-
mk/toolchain/gcc/rte.toolchain-compat.mk | 5 +++++
mk/toolchain/gcc/rte.vars.mk | 9 +++++++++
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/buildtools/pmdinfogen/Makefile b/buildtools/pmdinfogen/Makefile
index bf07b6f..ff7a5fa 100644
--- a/buildtools/pmdinfogen/Makefile
+++ b/buildtools/pmdinfogen/Makefile
@@ -41,7 +41,7 @@ HOSTAPP = dpdk-pmdinfogen
#
SRCS-y += pmdinfogen.c
-HOST_CFLAGS += $(WERROR_FLAGS) -g
+HOST_CFLAGS += $(HOST_WERROR_FLAGS) -g
HOST_CFLAGS += -I$(RTE_OUTPUT)/include
include $(RTE_SDK)/mk/rte.hostapp.mk
diff --git a/mk/toolchain/gcc/rte.toolchain-compat.mk
b/mk/toolchain/gcc/rte.toolchain-compat.mk
index 255c896..1e4434f 100644
--- a/mk/toolchain/gcc/rte.toolchain-compat.mk
+++ b/mk/toolchain/gcc/rte.toolchain-compat.mk
@@ -15,6 +15,11 @@ GCC_MINOR = $(shell echo __GNUC_MINOR__ | $(CC) -E -x c - |
tail -n 1)
GCC_PATCHLEVEL = $(shell echo __GNUC_PATCHLEVEL__ | $(CC) -E -x c - | tail -n
1)
GCC_VERSION = $(GCC_MAJOR)$(GCC_MINOR)
+HOST_GCC_MAJOR = $(shell echo __GNUC__ | $(HOSTCC) -E -x c - | tail -n 1)
+HOST_GCC_MINOR = $(shell echo __GNUC_MINOR__ | $(HOSTCC) -E -x c - | tail -n 1)
+HOST_GCC_PATCHLEVEL = $(shell echo __GNUC_PATCHLEVEL__ | $(HOSTCC) -E -x c - |
tail -n 1)
+HOST_GCC_VERSION = $(HOST_GCC_MAJOR)$(HOST_GCC_MINOR)
+
# if GCC is older than 4.x
ifeq ($(shell test $(GCC_VERSION) -lt 40 && echo 1), 1)
MACHINE_CFLAGS =
diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
index 7e4531b..d8b99fa 100644
--- a/mk/toolchain/gcc/rte.vars.mk
+++ b/mk/toolchain/gcc/rte.vars.mk
@@ -71,6 +71,15 @@ ifeq ($(shell test $(GCC_VERSION) -lt 47 && echo 1), 1)
WERROR_FLAGS += -Wno-uninitialized
endif
+HOST_WERROR_FLAGS := $(WERROR_FLAGS)
+
+ifeq ($(shell test $(HOST_GCC_VERSION) -gt 70 && echo 1), 1)
+# Tell GCC only to error for switch fallthroughs without a suitable comment
+HOST_WERROR_FLAGS += -Wimplicit-fallthrough=2
+# Ignore errors for snprintf truncation
+HOST_WERROR_FLAGS += -Wno-format-truncation
+endif
+
ifeq ($(shell test $(GCC_VERSION) -gt 70 && echo 1), 1)
# Tell GCC only to error for switch fallthroughs without a suitable comment
WERROR_FLAGS += -Wimplicit-fallthrough=2
--
2.1.4
