1# $FreeBSD$ 2 3# 4# Warning flags for compiling the kernel and components of the kernel: 5# 6CWARNFLAGS?= -Wall -Wnested-externs -Wstrict-prototypes \ 7 -Wmissing-prototypes -Wpointer-arith -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-error=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-error=unneeded-internal-declaration 25NO_WSOMETIMES_UNINITIALIZED= -Wno-error=sometimes-uninitialized 26NO_WCAST_QUAL= -Wno-error=cast-qual 27NO_WTAUTOLOGICAL_POINTER_COMPARE= -Wno-tautological-pointer-compare 28.if ${COMPILER_VERSION} >= 100000 29NO_WMISLEADING_INDENTATION= -Wno-misleading-indentation 30.endif 31.if ${COMPILER_VERSION} >= 130000 32NO_WUNUSED_BUT_SET_VARIABLE= -Wno-unused-but-set-variable 33.endif 34.if ${COMPILER_VERSION} >= 140000 35NO_WBITWISE_INSTEAD_OF_LOGICAL= -Wno-bitwise-instead-of-logical 36.endif 37.if ${COMPILER_VERSION} >= 150000 38NO_WSTRICT_PROTOTYPES= -Wno-strict-prototypes 39.endif 40# Several other warnings which might be useful in some cases, but not severe 41# enough to error out the whole kernel build. Display them anyway, so there is 42# some incentive to fix them eventually. 43CWARNEXTRA?= -Wno-error=tautological-compare -Wno-error=empty-body \ 44 -Wno-error=parentheses-equality -Wno-error=unused-function \ 45 -Wno-error=pointer-sign 46CWARNEXTRA+= -Wno-error=shift-negative-value 47CWARNEXTRA+= -Wno-address-of-packed-member 48.if ${COMPILER_VERSION} >= 150000 49CWARNEXTRA+= -Wno-error=array-parameter 50CWARNEXTRA+= -Wno-error=deprecated-non-prototype 51.endif 52.endif # clang 53 54.if ${COMPILER_TYPE} == "gcc" 55# Catch-all for all the things that are in our tree, but for which we're 56# not yet ready for this compiler. 57NO_WUNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable 58CWARNEXTRA?= -Wno-error=address \ 59 -Wno-error=aggressive-loop-optimizations \ 60 -Wno-error=array-bounds \ 61 -Wno-error=attributes \ 62 -Wno-error=cast-qual \ 63 -Wno-error=enum-compare \ 64 -Wno-error=maybe-uninitialized \ 65 -Wno-error=misleading-indentation \ 66 -Wno-error=nonnull-compare \ 67 -Wno-error=overflow \ 68 -Wno-error=sequence-point \ 69 -Wno-error=shift-overflow \ 70 -Wno-error=tautological-compare \ 71 -Wno-unused-but-set-variable 72.if ${COMPILER_VERSION} >= 70100 73CWARNEXTRA+= -Wno-error=stringop-overflow 74.endif 75.if ${COMPILER_VERSION} >= 70200 76CWARNEXTRA+= -Wno-error=memset-elt-size 77.endif 78.if ${COMPILER_VERSION} >= 80000 79CWARNEXTRA+= -Wno-error=packed-not-aligned 80.endif 81.if ${COMPILER_VERSION} >= 90100 82CWARNEXTRA+= -Wno-address-of-packed-member \ 83 -Wno-error=alloca-larger-than= 84.if ${COMPILER_VERSION} >= 120100 85CWARNEXTRA+= -Wno-error=nonnull \ 86 -Wno-dangling-pointer \ 87 -Wno-zero-length-bounds 88NO_WINFINITE_RECURSION= -Wno-infinite-recursion 89NO_WSTRINGOP_OVERREAD= -Wno-stringop-overread 90.endif 91.endif 92 93# GCC produces false positives for functions that switch on an 94# enum (GCC bug 87950) 95CWARNFLAGS+= -Wno-return-type 96.endif # gcc 97 98# This warning is utter nonsense 99CWARNFLAGS+= -Wno-format-zero-length 100 101# External compilers may not support our format extensions. Allow them 102# to be disabled. WARNING: format checking is disabled in this case. 103.if ${MK_FORMAT_EXTENSIONS} == "no" 104FORMAT_EXTENSIONS= -Wno-format 105.elif ${COMPILER_TYPE} == "clang" || \ 106 (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100) 107FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 108.else 109FORMAT_EXTENSIONS= -fformat-extensions 110.endif 111 112# 113# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 114# and above adds code to the entry and exit point of every function to align the 115# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 116# per function call. While the 16-byte alignment may benefit micro benchmarks, 117# it is probably an overall loss as it makes the code bigger (less efficient 118# use of code cache tag lines) and uses more stack (less efficient use of data 119# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 120# operations inside the kernel itself. These operations are exclusively 121# reserved for user applications. 122# 123# gcc: 124# Setting -mno-mmx implies -mno-3dnow 125# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 126# 127# clang: 128# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 129# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 130# 131.if ${MACHINE_CPUARCH} == "i386" 132CFLAGS.gcc+= -mpreferred-stack-boundary=2 133CFLAGS.clang+= -mno-aes -mno-avx 134CFLAGS+= -mno-mmx -mno-sse -msoft-float 135INLINE_LIMIT?= 8000 136.endif 137 138.if ${MACHINE_CPUARCH} == "arm" 139INLINE_LIMIT?= 8000 140.endif 141 142.if ${MACHINE_CPUARCH} == "aarch64" 143# We generally don't want fpu instructions in the kernel. 144CFLAGS += -mgeneral-regs-only 145# Reserve x18 for pcpu data 146CFLAGS += -ffixed-x18 147INLINE_LIMIT?= 8000 148.endif 149 150# 151# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 152# point registers within the kernel. However, for kernels supporting hardware 153# float (FPE), we have to include that in the march so we can have limited 154# floating point support in context switching needed for that. This is different 155# than userland where we use a hard-float ABI (lp64d). 156# 157# We also specify the "medium" code model, which generates code suitable for a 158# 2GiB addressing range located at any offset, allowing modules to be located 159# anywhere in the 64-bit address space. Note that clang and GCC refer to this 160# code model as "medium" and "medany" respectively. 161# 162.if ${MACHINE_CPUARCH} == "riscv" 163CFLAGS+= -march=rv64imafdc 164CFLAGS+= -mabi=lp64 165CFLAGS.clang+= -mcmodel=medium 166CFLAGS.gcc+= -mcmodel=medany 167INLINE_LIMIT?= 8000 168 169.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 170CFLAGS+= -mno-relax 171.endif 172.endif 173 174# 175# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 176# operations inside the kernel itself. These operations are exclusively 177# reserved for user applications. 178# 179# gcc: 180# Setting -mno-mmx implies -mno-3dnow 181# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 182# 183# clang: 184# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 185# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 186# (-mfpmath= is not supported) 187# 188.if ${MACHINE_CPUARCH} == "amd64" 189CFLAGS.clang+= -mno-aes -mno-avx 190CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 191 -fno-asynchronous-unwind-tables 192INLINE_LIMIT?= 8000 193.endif 194 195# 196# For PowerPC we tell gcc to use floating point emulation. This avoids using 197# floating point registers for integer operations which it has a tendency to do. 198# Also explicitly disable Altivec instructions inside the kernel. 199# 200.if ${MACHINE_CPUARCH} == "powerpc" 201CFLAGS+= -mno-altivec -msoft-float 202INLINE_LIMIT?= 15000 203.endif 204 205.if ${MACHINE_ARCH} == "powerpcspe" 206CFLAGS.gcc+= -mno-spe 207.endif 208 209# 210# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 211# DDB happy. ELFv2, if available, has some other efficiency benefits. 212# 213.if ${MACHINE_ARCH:Mpowerpc64*} != "" 214CFLAGS+= -mabi=elfv2 215.endif 216 217# 218# GCC 3.0 and above like to do certain optimizations based on the 219# assumption that the program is linked against libc. Stop this. 220# 221CFLAGS+= -ffreestanding 222 223# 224# The C standard leaves signed integer overflow behavior undefined. 225# gcc and clang opimizers take advantage of this. The kernel makes 226# use of signed integer wraparound mechanics so we need the compiler 227# to treat it as a wraparound and not take shortcuts. 228# 229CFLAGS+= -fwrapv 230 231# 232# GCC SSP support 233# 234.if ${MK_SSP} != "no" 235CFLAGS+= -fstack-protector 236.endif 237 238# 239# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 240# 241.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 242 ${MK_KERNEL_RETPOLINE} != "no" 243CFLAGS+= -mretpoline 244.endif 245 246# 247# Initialize stack variables on function entry 248# 249.if ${MK_INIT_ALL_ZERO} == "yes" 250.if ${COMPILER_FEATURES:Minit-all} 251CFLAGS+= -ftrivial-auto-var-init=zero \ 252 -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang 253.else 254.warning InitAll (zeros) requested but not support by compiler 255.endif 256.elif ${MK_INIT_ALL_PATTERN} == "yes" 257.if ${COMPILER_FEATURES:Minit-all} 258CFLAGS+= -ftrivial-auto-var-init=pattern 259.else 260.warning InitAll (pattern) requested but not support by compiler 261.endif 262.endif 263 264CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 265CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 266CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 267 268# Tell bmake not to mistake standard targets for things to be searched for 269# or expect to ever be up-to-date. 270PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 271 beforelinking build build-tools buildfiles buildincludes \ 272 checkdpadd clean cleandepend cleandir cleanobj configure \ 273 depend distclean distribute exe \ 274 html includes install installfiles installincludes \ 275 obj objlink objs objwarn \ 276 realinstall regress \ 277 tags whereobj 278 279.PHONY: ${PHONY_NOTMAIN} 280.NOTMAIN: ${PHONY_NOTMAIN} 281 282CSTD= c99 283 284.if ${CSTD} == "k&r" 285CFLAGS+= -traditional 286.elif ${CSTD} == "c89" || ${CSTD} == "c90" 287CFLAGS+= -std=iso9899:1990 288.elif ${CSTD} == "c94" || ${CSTD} == "c95" 289CFLAGS+= -std=iso9899:199409 290.elif ${CSTD} == "c99" 291CFLAGS+= -std=iso9899:1999 292.else # CSTD 293CFLAGS+= -std=${CSTD} 294.endif # CSTD 295 296# Please keep this if in sync with bsd.sys.mk 297.if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld") 298# Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld". 299.if ${COMPILER_TYPE} == "clang" 300# Note: Clang does not like relative paths for ld so we map ld.lld -> lld. 301.if ${COMPILER_VERSION} >= 120000 302CCLDFLAGS+= --ld-path=${LD:[1]:S/^ld.//1W} 303.else 304CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W} 305.endif 306.else 307# GCC does not support an absolute path for -fuse-ld so we just print this 308# warning instead and let the user add the required symlinks. 309# However, we can avoid this warning if -B is set appropriately (e.g. for 310# CROSS_TOOLCHAIN=...-gcc). 311.if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/}) 312.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported 313.endif 314.endif 315.endif 316 317# Set target-specific linker emulation name. 318LD_EMULATION_aarch64=aarch64elf 319LD_EMULATION_amd64=elf_x86_64_fbsd 320LD_EMULATION_arm=armelf_fbsd 321LD_EMULATION_armv6=armelf_fbsd 322LD_EMULATION_armv7=armelf_fbsd 323LD_EMULATION_i386=elf_i386_fbsd 324LD_EMULATION_powerpc= elf32ppc_fbsd 325LD_EMULATION_powerpcspe= elf32ppc_fbsd 326LD_EMULATION_powerpc64= elf64ppc_fbsd 327LD_EMULATION_powerpc64le= elf64lppc_fbsd 328LD_EMULATION_riscv64= elf64lriscv 329LD_EMULATION_riscv64sf= elf64lriscv 330LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 331