[dpdk-stable] patch 'mk: fix cross build' has been queued to stable release 18.05.1

[Christian Ehrhardt]

Hi,

FYI, your patch has been queued to stable release 18.05.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 08/01/18. So please
shout if anyone has objections.

Thanks.

Christian Ehrhardt <christian.ehrhardt at canonical.com>

---
>From 3786acf1299ab213bc58ac5d4148d0583d794133 Mon Sep 17 00:00:00 2001
From: Gavin Hu <gavin.hu at arm.com>
Date: Sat, 30 Jun 2018 01:27:33 +0800
Subject: [PATCH] mk: fix cross build
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[ upstream commit ebaa070de85e49ad01214b1940c7cdcdba2f4ef6 ]

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")

Signed-off-by: Gavin Hu <gavin.hu at arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
Reviewed-by: Steve Capper <steve.capper at arm.com>
Tested-by: Ali Alnubani <alialnu at mellanox.com>
Acked-by: Thomas Monjalon <thomas at 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 bf07b6f2e..ff7a5fae6 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 255c89677..1e4434fa9 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 $(GCC_VERSION) -lt 40 && echo 1), 1)
 	MACHINE_CFLAGS =
diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
index 7e4531bab..d8b99faf6 100644
--- a/mk/toolchain/gcc/rte.vars.mk
+++ b/mk/toolchain/gcc/rte.vars.mk
@@ -71,6 +71,15 @@ ifeq ($(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
-- 
2.17.1