[dpdk-dev] [PATCH v2] mk: Only default to -Werror when building from git checkout

[Panu Matilainen <pmatilai@redhat.com>]

Add RTE_DEVEL_BUILD make-variable which can be used to do things
differently when doing development vs building a release,
autodetected from source root .git presence and overridable via
commandline. Use it to only enable -Werror compiler flag when
building a git checkout:

Failing build on warnings is a useful developer tool but its bad
for release tarballs which can and do get built with newer
compilers than what was used/available during development. Compilers
routinely add new warnings so code which built silently with cc X
might no longer do so with X+1. This doesn't make the existing code
any more buggier and failing the build in this case does not help
not help improve code quality of an already released version either.
---
 mk/rte.vars.mk                 | 4 ++++
 mk/toolchain/clang/rte.vars.mk | 6 +++++-
 mk/toolchain/gcc/rte.vars.mk   | 6 +++++-
 mk/toolchain/icc/rte.vars.mk   | 6 +++++-
 4 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/mk/rte.vars.mk b/mk/rte.vars.mk
index d5b36be..a4ad367 100644
--- a/mk/rte.vars.mk
+++ b/mk/rte.vars.mk
@@ -71,6 +71,10 @@ ifneq ($(BUILDING_RTE_SDK),)
   ifeq ($(RTE_BUILD_COMBINE_LIBS),)
     RTE_BUILD_COMBINE_LIBS := n
   endif
+  # see if we're building from git
+  ifneq ($(wildcard $(RTE_SDK)/.git),)
+    RTE_DEVEL_BUILD := y
+  endif
 endif
 
 RTE_LIBNAME := $(CONFIG_RTE_LIBNAME:"%"=%)
diff --git a/mk/toolchain/clang/rte.vars.mk b/mk/toolchain/clang/rte.vars.mk
index 40cb389..01b1860 100644
--- a/mk/toolchain/clang/rte.vars.mk
+++ b/mk/toolchain/clang/rte.vars.mk
@@ -63,12 +63,16 @@ TOOLCHAIN_ASFLAGS =
 TOOLCHAIN_CFLAGS =
 TOOLCHAIN_LDFLAGS =
 
-WERROR_FLAGS := -W -Wall -Werror -Wstrict-prototypes -Wmissing-prototypes
+WERROR_FLAGS := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
 WERROR_FLAGS += -Wmissing-declarations -Wold-style-definition -Wpointer-arith
 WERROR_FLAGS += -Wnested-externs -Wcast-qual
 WERROR_FLAGS += -Wformat-nonliteral -Wformat-security
 WERROR_FLAGS += -Wundef -Wwrite-strings
 
+ifeq ($(RTE_DEVEL_BUILD),y)
+WERROR_FLAGS += -Werror
+endif
+
 # process cpu flags
 include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
 
diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
index 88f235c..fc3a642 100644
--- a/mk/toolchain/gcc/rte.vars.mk
+++ b/mk/toolchain/gcc/rte.vars.mk
@@ -71,12 +71,16 @@ ifeq (,$(findstring -O0,$(EXTRA_CFLAGS)))
 endif
 endif
 
-WERROR_FLAGS := -W -Wall -Werror -Wstrict-prototypes -Wmissing-prototypes
+WERROR_FLAGS := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
 WERROR_FLAGS += -Wmissing-declarations -Wold-style-definition -Wpointer-arith
 WERROR_FLAGS += -Wcast-align -Wnested-externs -Wcast-qual
 WERROR_FLAGS += -Wformat-nonliteral -Wformat-security
 WERROR_FLAGS += -Wundef -Wwrite-strings
 
+ifeq ($(RTE_DEVEL_BUILD),y)
+WERROR_FLAGS += -Werror
+endif
+
 # process cpu flags
 include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
 
diff --git a/mk/toolchain/icc/rte.vars.mk b/mk/toolchain/icc/rte.vars.mk
index e39d710..0850719 100644
--- a/mk/toolchain/icc/rte.vars.mk
+++ b/mk/toolchain/icc/rte.vars.mk
@@ -69,9 +69,13 @@ TOOLCHAIN_ASFLAGS =
 #   error #13368: loop was not vectorized with "vector always assert"
 #   error #15527: loop was not vectorized: function call to fprintf cannot be vectorize
 #                   was declared "deprecated"
-WERROR_FLAGS := -Wall -Werror-all -w2 -diag-disable 271 -diag-warning 1478
+WERROR_FLAGS := -Wall -w2 -diag-disable 271 -diag-warning 1478
 WERROR_FLAGS += -diag-disable 13368 -diag-disable 15527
 
+ifeq ($(RTE_DEVEL_BUILD),y)
+WERROR_FLAGS += -Werror-all
+endif
+
 # process cpu flags
 include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
 # disable max-inline params boundaries for ICC 15 compiler
-- 
2.1.0