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} >= 40800 46# Catch-all for all the things that are in our tree, but for which we're 47# not yet ready for this compiler. 48CWARNEXTRA?= -Wno-error=inline -Wno-error=enum-compare -Wno-error=unused-but-set-variable \ 49 -Wno-error=aggressive-loop-optimizations -Wno-error=maybe-uninitialized \ 50 -Wno-error=array-bounds -Wno-error=address \ 51 -Wno-error=cast-qual -Wno-error=sequence-point -Wno-error=attributes \ 52 -Wno-error=strict-overflow -Wno-error=overflow 53.if ${COMPILER_VERSION} >= 60100 54CWARNEXTRA+= -Wno-error=nonnull-compare -Wno-error=shift-overflow 55.endif 56.else 57# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 58CWARNEXTRA?= -Wno-uninitialized 59.endif 60.endif 61 62# External compilers may not support our format extensions. Allow them 63# to be disabled. WARNING: format checking is disabled in this case. 64.if ${MK_FORMAT_EXTENSIONS} == "no" 65FORMAT_EXTENSIONS= -Wno-format 66.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 67FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 68.else 69FORMAT_EXTENSIONS= -fformat-extensions 70.endif 71 72# 73# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 74# and above adds code to the entry and exit point of every function to align the 75# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 76# per function call. While the 16-byte alignment may benefit micro benchmarks, 77# it is probably an overall loss as it makes the code bigger (less efficient 78# use of code cache tag lines) and uses more stack (less efficient use of data 79# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 80# operations inside the kernel itself. These operations are exclusively 81# reserved for user applications. 82# 83# gcc: 84# Setting -mno-mmx implies -mno-3dnow 85# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 86# 87# clang: 88# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 89# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 90# 91.if ${MACHINE_CPUARCH} == "i386" 92CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 93CFLAGS.clang+= -mno-aes -mno-avx 94CFLAGS+= -mno-mmx -mno-sse -msoft-float 95INLINE_LIMIT?= 8000 96.endif 97 98.if ${MACHINE_CPUARCH} == "arm" 99INLINE_LIMIT?= 8000 100.endif 101 102.if ${MACHINE_CPUARCH} == "aarch64" 103# We generally don't want fpu instructions in the kernel. 104CFLAGS += -mgeneral-regs-only 105# Reserve x18 for pcpu data 106CFLAGS += -ffixed-x18 107.endif 108 109.if ${MACHINE_CPUARCH} == "riscv" 110CFLAGS.gcc+= -mcmodel=medany 111INLINE_LIMIT?= 8000 112.endif 113 114# 115# For sparc64 we want the medany code model so modules may be located 116# anywhere in the 64-bit address space. We also tell GCC to use floating 117# point emulation. This avoids using floating point registers for integer 118# operations which it has a tendency to do. 119# 120.if ${MACHINE_CPUARCH} == "sparc64" 121CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 122CFLAGS.gcc+= -mcmodel=medany -msoft-float 123INLINE_LIMIT?= 15000 124.endif 125 126# 127# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 128# operations inside the kernel itself. These operations are exclusively 129# reserved for user applications. 130# 131# gcc: 132# Setting -mno-mmx implies -mno-3dnow 133# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 134# 135# clang: 136# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 137# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 138# (-mfpmath= is not supported) 139# 140.if ${MACHINE_CPUARCH} == "amd64" 141CFLAGS.clang+= -mno-aes -mno-avx 142CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 143 -fno-asynchronous-unwind-tables 144INLINE_LIMIT?= 8000 145.endif 146 147# 148# For PowerPC we tell gcc to use floating point emulation. This avoids using 149# floating point registers for integer operations which it has a tendency to do. 150# Also explicitly disable Altivec instructions inside the kernel. 151# 152.if ${MACHINE_CPUARCH} == "powerpc" 153CFLAGS+= -mno-altivec 154CFLAGS.clang+= -mllvm -disable-ppc-float-in-variadic=true 155CFLAGS.gcc+= -msoft-float 156INLINE_LIMIT?= 15000 157.endif 158 159# 160# Use dot symbols on powerpc64 to make ddb happy 161# 162.if ${MACHINE_ARCH} == "powerpc64" 163CFLAGS.gcc+= -mcall-aixdesc 164.endif 165 166# 167# For MIPS we also tell gcc to use floating point emulation 168# 169.if ${MACHINE_CPUARCH} == "mips" 170CFLAGS+= -msoft-float 171INLINE_LIMIT?= 8000 172.endif 173 174# 175# GCC 3.0 and above like to do certain optimizations based on the 176# assumption that the program is linked against libc. Stop this. 177# 178CFLAGS+= -ffreestanding 179 180# 181# The C standard leaves signed integer overflow behavior undefined. 182# gcc and clang opimizers take advantage of this. The kernel makes 183# use of signed integer wraparound mechanics so we need the compiler 184# to treat it as a wraparound and not take shortcuts. 185# 186CFLAGS+= -fwrapv 187 188# 189# GCC SSP support 190# 191.if ${MK_SSP} != "no" && \ 192 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 193CFLAGS+= -fstack-protector 194.endif 195 196# 197# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 198# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 199# cope well with DWARF 4, so force it to genereate DWARF2, which they 200# understand. Do this unconditionally as it is harmless when not needed, 201# but critical for these newer versions. 202# 203.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 204CFLAGS+= -gdwarf-2 205.endif 206 207CFLAGS+= ${CWARNFLAGS} ${CWARNFLAGS.${.IMPSRC:T}} 208CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 209 210# Tell bmake not to mistake standard targets for things to be searched for 211# or expect to ever be up-to-date. 212PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 213 beforelinking build build-tools buildfiles buildincludes \ 214 checkdpadd clean cleandepend cleandir cleanobj configure \ 215 depend distclean distribute exe \ 216 html includes install installfiles installincludes lint \ 217 obj objlink objs objwarn \ 218 realinstall regress \ 219 tags whereobj 220 221.PHONY: ${PHONY_NOTMAIN} 222.NOTMAIN: ${PHONY_NOTMAIN} 223 224CSTD= c99 225 226.if ${CSTD} == "k&r" 227CFLAGS+= -traditional 228.elif ${CSTD} == "c89" || ${CSTD} == "c90" 229CFLAGS+= -std=iso9899:1990 230.elif ${CSTD} == "c94" || ${CSTD} == "c95" 231CFLAGS+= -std=iso9899:199409 232.elif ${CSTD} == "c99" 233CFLAGS+= -std=iso9899:1999 234.else # CSTD 235CFLAGS+= -std=${CSTD} 236.endif # CSTD 237