mk: fix cross build

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 gcc is older than 7.0, or the
host cc compiler is clang, 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/dpdk/build/include    -o pmdinfogen.o -c
~/dpdk/buildtools/pmdinfogen/pmdinfogen.c gcc: error:
unrecognized command line option ‘-Wimplicit-fallthrough=2’

Fixes: ced3e6f8 ("mk: adjust gcc flags for new gcc 7 warnings")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Tested-by: Ali Alnubani <alialnu@mellanox.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>

diff --git a/buildtools/pmdinfogen/Makefile b/buildtools/pmdinfogen/Makefile
index bf07b6f2eddd3653927a94c17ba262f9cc016a3c..ff7a5fae66cccf03ce9a999e65bbaf7ca18e7e25 100644 (file)
--- 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 255c896775909a1c229883fe74033d661409893b..1e4434fa9804b4c9ffb97beea68746f361615e12 100644 (file)
--- 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 7e4531bab355a0660dd8fcccb47019ed8a300219..d8b99faf6c5782db353ced6a4b6ca8eac28ea3d5 100644 (file)
--- 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