1# $FreeBSD$ 2 3# 4# Warning flags for compiling the kernel and components of the kernel: 5# 6CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \ 7 -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \ 8 -Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \ 9 -Wmissing-include-dirs -fdiagnostics-show-option \ 10 -Wno-unknown-pragmas \ 11 ${CWARNEXTRA} 12# 13# The following flags are next up for working on: 14# -Wextra 15 16# Disable a few warnings for clang, since there are several places in the 17# kernel where fixing them is more trouble than it is worth, or where there is 18# a false positive. 19.if ${COMPILER_TYPE} == "clang" 20NO_WCONSTANT_CONVERSION= -Wno-constant-conversion 21NO_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative 22NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow 23NO_WSELF_ASSIGN= -Wno-self-assign 24NO_WUNNEEDED_INTERNAL_DECL= -Wno-unneeded-internal-declaration 25NO_WSOMETIMES_UNINITIALIZED= -Wno-error-sometimes-uninitialized 26NO_WCAST_QUAL= -Wno-cast-qual 27# Several other warnings which might be useful in some cases, but not severe 28# enough to error out the whole kernel build. Display them anyway, so there is 29# some incentive to fix them eventually. 30CWARNEXTRA?= -Wno-error-tautological-compare -Wno-error-empty-body \ 31 -Wno-error-parentheses-equality -Wno-error-unused-function \ 32 -Wno-error-pointer-sign 33.if ${COMPILER_VERSION} >= 30700 34CWARNEXTRA+= -Wno-error-shift-negative-value 35.endif 36 37CLANG_NO_IAS= -no-integrated-as 38.if ${COMPILER_VERSION} < 30500 39# XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives 40CLANG_NO_IAS34= -no-integrated-as 41.endif 42.endif 43 44.if ${COMPILER_TYPE} == "gcc" 45.if ${COMPILER_VERSION} >= 40300 46# Catch-all for all the things that are in our tree, but for which we're 47# not yet ready for this compiler. Note: we likely only really "support" 48# building with gcc 4.8 and newer. Nothing older has been tested. 49CWARNEXTRA?= -Wno-error=inline -Wno-error=enum-compare -Wno-error=unused-but-set-variable \ 50 -Wno-error=aggressive-loop-optimizations -Wno-error=maybe-uninitialized \ 51 -Wno-error=array-bounds -Wno-error=address \ 52 -Wno-error=cast-qual -Wno-error=sequence-point -Wno-error=attributes \ 53 -Wno-error=strict-overflow -Wno-error=overflow 54.else 55# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 56CWARNEXTRA?= -Wno-uninitialized 57.endif 58.endif 59 60# External compilers may not support our format extensions. Allow them 61# to be disabled. WARNING: format checking is disabled in this case. 62.if ${MK_FORMAT_EXTENSIONS} == "no" 63FORMAT_EXTENSIONS= -Wno-format 64.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 65FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 66.else 67FORMAT_EXTENSIONS= -fformat-extensions 68.endif 69 70# 71# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 72# and above adds code to the entry and exit point of every function to align the 73# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 74# per function call. While the 16-byte alignment may benefit micro benchmarks, 75# it is probably an overall loss as it makes the code bigger (less efficient 76# use of code cache tag lines) and uses more stack (less efficient use of data 77# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 78# operations inside the kernel itself. These operations are exclusively 79# reserved for user applications. 80# 81# gcc: 82# Setting -mno-mmx implies -mno-3dnow 83# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 84# 85# clang: 86# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 87# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 88# 89.if ${MACHINE_CPUARCH} == "i386" 90CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 91CFLAGS.clang+= -mno-aes -mno-avx 92CFLAGS+= -mno-mmx -mno-sse -msoft-float 93INLINE_LIMIT?= 8000 94.endif 95 96.if ${MACHINE_CPUARCH} == "arm" 97INLINE_LIMIT?= 8000 98.endif 99 100.if ${MACHINE_CPUARCH} == "aarch64" 101# We generally don't want fpu instructions in the kernel. 102CFLAGS += -mgeneral-regs-only 103# Reserve x18 for pcpu data 104CFLAGS += -ffixed-x18 105.endif 106 107.if ${MACHINE_CPUARCH} == "riscv" 108INLINE_LIMIT?= 8000 109.endif 110 111# 112# For sparc64 we want the medany code model so modules may be located 113# anywhere in the 64-bit address space. We also tell GCC to use floating 114# point emulation. This avoids using floating point registers for integer 115# operations which it has a tendency to do. 116# 117.if ${MACHINE_CPUARCH} == "sparc64" 118CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 119CFLAGS.gcc+= -mcmodel=medany -msoft-float 120INLINE_LIMIT?= 15000 121.endif 122 123# 124# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 125# operations inside the kernel itself. These operations are exclusively 126# reserved for user applications. 127# 128# gcc: 129# Setting -mno-mmx implies -mno-3dnow 130# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 131# 132# clang: 133# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 134# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 135# (-mfpmath= is not supported) 136# 137.if ${MACHINE_CPUARCH} == "amd64" 138CFLAGS.clang+= -mno-aes -mno-avx 139CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 140 -fno-asynchronous-unwind-tables 141INLINE_LIMIT?= 8000 142.endif 143 144# 145# For PowerPC we tell gcc to use floating point emulation. This avoids using 146# floating point registers for integer operations which it has a tendency to do. 147# Also explicitly disable Altivec instructions inside the kernel. 148# 149.if ${MACHINE_CPUARCH} == "powerpc" 150CFLAGS+= -mno-altivec 151CFLAGS.clang+= -mllvm -disable-ppc-float-in-variadic=true 152CFLAGS.gcc+= -msoft-float 153INLINE_LIMIT?= 15000 154.endif 155 156# 157# Use dot symbols on powerpc64 to make ddb happy 158# 159.if ${MACHINE_ARCH} == "powerpc64" 160CFLAGS.gcc+= -mcall-aixdesc 161.endif 162 163# 164# For MIPS we also tell gcc to use floating point emulation 165# 166.if ${MACHINE_CPUARCH} == "mips" 167CFLAGS+= -msoft-float 168INLINE_LIMIT?= 8000 169.endif 170 171# 172# GCC 3.0 and above like to do certain optimizations based on the 173# assumption that the program is linked against libc. Stop this. 174# 175CFLAGS+= -ffreestanding 176 177# 178# The C standard leaves signed integer overflow behavior undefined. 179# gcc and clang opimizers take advantage of this. The kernel makes 180# use of signed integer wraparound mechanics so we need the compiler 181# to treat it as a wraparound and not take shortcuts. 182# 183CFLAGS+= -fwrapv 184 185# 186# GCC SSP support 187# 188.if ${MK_SSP} != "no" && \ 189 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 190CFLAGS+= -fstack-protector 191.endif 192 193# 194# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 195# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 196# cope well with DWARF 4, so force it to genereate DWARF2, which they 197# understand. Do this unconditionally as it is harmless when not needed, 198# but critical for these newer versions. 199# 200.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 201CFLAGS+= -gdwarf-2 202.endif 203 204CFLAGS+= ${CWARNFLAGS} ${CWARNFLAGS.${.IMPSRC:T}} 205CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 206 207# Tell bmake not to mistake standard targets for things to be searched for 208# or expect to ever be up-to-date. 209PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 210 beforelinking build build-tools buildfiles buildincludes \ 211 checkdpadd clean cleandepend cleandir cleanobj configure \ 212 depend dependall distclean distribute exe \ 213 html includes install installfiles installincludes lint \ 214 obj objlink objs objwarn realall realdepend \ 215 realinstall regress subdir-all subdir-depend subdir-install \ 216 tags whereobj 217 218.PHONY: ${PHONY_NOTMAIN} 219.NOTMAIN: ${PHONY_NOTMAIN} 220 221CSTD= c99 222 223.if ${CSTD} == "k&r" 224CFLAGS+= -traditional 225.elif ${CSTD} == "c89" || ${CSTD} == "c90" 226CFLAGS+= -std=iso9899:1990 227.elif ${CSTD} == "c94" || ${CSTD} == "c95" 228CFLAGS+= -std=iso9899:199409 229.elif ${CSTD} == "c99" 230CFLAGS+= -std=iso9899:1999 231.else # CSTD 232CFLAGS+= -std=${CSTD} 233.endif # CSTD 234