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freebsd/sys/conf/kern.mk
Warner Losh 7ed11c5e5a Fix module builds on arm (and maybe others) by turning off a whole
raft of new warnings that appear to be on by default in clang 3.5.0.
Fix RPI-B build issues with new clang not liking the ability to pass
arbitrary flags to as, since some flags are more arbitrary (and thus
verboten) than others.

These warnings should be actually fixed in the code, but this is a
band-aide to get things (almost) building again.
2015-01-01 02:00:04 +00:00

190 lines
6.7 KiB
Makefile

# $FreeBSD$
#
# Warning flags for compiling the kernel and components of the kernel:
#
CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
-Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
-Wmissing-include-dirs -fdiagnostics-show-option \
${CWARNEXTRA}
#
# The following flags are next up for working on:
# -Wextra
# Disable a few warnings for clang, since there are several places in the
# kernel where fixing them is more trouble than it is worth, or where there is
# a false positive.
.if ${COMPILER_TYPE} == "clang"
NO_WCONSTANT_CONVERSION= -Wno-constant-conversion
NO_WARRAY_BOUNDS= -Wno-array-bounds
NO_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative
NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow
NO_WUNUSED_VALUE= -Wno-unused-value
NO_WSELF_ASSIGN= -Wno-self-assign
NO_WFORMAT_SECURITY= -Wno-format-security
NO_WUNNEEDED_INTERNAL_DECL= -Wno-unneeded-internal-declaration
NO_WSOMETIMES_UNINITIALIZED= -Wno-error-sometimes-uninitialized
# Several other warnings which might be useful in some cases, but not severe
# enough to error out the whole kernel build. Display them anyway, so there is
# some incentive to fix them eventually.
CWARNEXTRA?= -Wno-error-tautological-compare -Wno-error-empty-body \
-Wno-error-parentheses-equality -Wno-error-unused-function
.endif
.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 40300
# Catch-all for all the things that are in our tree, but for which we're
# not yet ready for this compiler. Note: we likely only really "support"
# building with gcc 4.8 and newer. Nothing older has been tested.
CWARNEXTRA?= -Wno-error=inline -Wno-error=enum-compare -Wno-error=unused-but-set-variable \
-Wno-error=aggressive-loop-optimizations -Wno-error=maybe-uninitialized \
-Wno-error=array-bounds -Wno-error=address \
-Wno-error=cast-qual -Wno-error=sequence-point -Wno-error=attributes \
-Wno-error=strict-overflow -Wno-error=overflow
.endif
# External compilers may not support our format extensions. Allow them
# to be disabled. WARNING: format checking is disabled in this case.
.if ${MK_FORMAT_EXTENSIONS} == "no"
FORMAT_EXTENSIONS= -Wno-format
.else
FORMAT_EXTENSIONS= -fformat-extensions
.endif
#
# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95
# and above adds code to the entry and exit point of every function to align the
# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
# per function call. While the 16-byte alignment may benefit micro benchmarks,
# it is probably an overall loss as it makes the code bigger (less efficient
# use of code cache tag lines) and uses more stack (less efficient use of data
# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD
# operations inside the kernel itself. These operations are exclusively
# reserved for user applications.
#
# gcc:
# Setting -mno-mmx implies -mno-3dnow
# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3
#
# clang:
# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
#
.if ${MACHINE_CPUARCH} == "i386"
CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2
CFLAGS.clang+= -mno-aes -mno-avx
CFLAGS+= -mno-mmx -mno-sse -msoft-float
INLINE_LIMIT?= 8000
.endif
.if ${MACHINE_CPUARCH} == "arm"
INLINE_LIMIT?= 8000
.endif
#
# For sparc64 we want the medany code model so modules may be located
# anywhere in the 64-bit address space. We also tell GCC to use floating
# point emulation. This avoids using floating point registers for integer
# operations which it has a tendency to do.
#
.if ${MACHINE_CPUARCH} == "sparc64"
CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm
CFLAGS.gcc+= -mcmodel=medany -msoft-float
INLINE_LIMIT?= 15000
.endif
#
# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
# operations inside the kernel itself. These operations are exclusively
# reserved for user applications.
#
# gcc:
# Setting -mno-mmx implies -mno-3dnow
# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
#
# clang:
# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
# (-mfpmath= is not supported)
#
.if ${MACHINE_CPUARCH} == "amd64"
CFLAGS.clang+= -mno-aes -mno-avx
CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \
-fno-asynchronous-unwind-tables
INLINE_LIMIT?= 8000
.endif
#
# For PowerPC we tell gcc to use floating point emulation. This avoids using
# floating point registers for integer operations which it has a tendency to do.
# Also explicitly disable Altivec instructions inside the kernel.
#
.if ${MACHINE_CPUARCH} == "powerpc"
CFLAGS+= -msoft-float -mno-altivec
INLINE_LIMIT?= 15000
.endif
#
# Use dot symbols on powerpc64 to make ddb happy
#
.if ${MACHINE_ARCH} == "powerpc64"
CFLAGS+= -mcall-aixdesc
.endif
#
# For MIPS we also tell gcc to use floating point emulation
#
.if ${MACHINE_CPUARCH} == "mips"
CFLAGS+= -msoft-float
INLINE_LIMIT?= 8000
.endif
#
# GCC 3.0 and above like to do certain optimizations based on the
# assumption that the program is linked against libc. Stop this.
#
CFLAGS+= -ffreestanding
#
# GCC SSP support
#
.if ${MK_SSP} != "no" && \
${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
CFLAGS+= -fstack-protector
.endif
#
# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4
# and gcc 4.8 is to generate DWARF version 4. However, our tools don't
# cope well with DWARF 4, so force it to genereate DWARF2, which they
# understand. Do this unconditionally as it is harmless when not needed,
# but critical for these newer versions.
#
.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == ""
CFLAGS+= -gdwarf-2
.endif
# A whole bunch of new default warnings in clang 3.5 subpress for now until
# this can be cleaned up.
.if ${COMPILER_VERSION} >= 30500
CFLAGS.clang+= -Wno-pointer-sign -Wno-constant-conversion -Wno-format \
-Wno-shift-count-negative -Wno-tautological-pointer-compare \
-Wno-shift-count-overflow -Wno-tautological-compare
.endif
CFLAGS+= ${CFLAGS.${COMPILER_TYPE}}
# Tell bmake not to mistake standard targets for things to be searched for
# or expect to ever be up-to-date.
PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \
beforelinking build build-tools buildfiles buildincludes \
checkdpadd clean cleandepend cleandir cleanobj configure \
depend dependall distclean distribute exe \
html includes install installfiles installincludes lint \
obj objlink objs objwarn realall realdepend \
realinstall regress subdir-all subdir-depend subdir-install \
tags whereobj
.PHONY: ${PHONY_NOTMAIN}
.NOTMAIN: ${PHONY_NOTMAIN}