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 -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 28NO_WARRAY_BOUNDS= -Wno-error-array-bounds 29# Several other warnings which might be useful in some cases, but not severe 30# enough to error out the whole kernel build. Display them anyway, so there is 31# some incentive to fix them eventually. 32CWARNEXTRA?= -Wno-error-tautological-compare -Wno-error-empty-body \ 33 -Wno-error-parentheses-equality -Wno-error-unused-function \ 34 -Wno-error-pointer-sign 35.if ${COMPILER_VERSION} >= 30700 36CWARNEXTRA+= -Wno-error-shift-negative-value 37.endif 38.if ${COMPILER_VERSION} >= 40000 39CWARNEXTRA+= -Wno-address-of-packed-member 40.endif 41 42CLANG_NO_IAS= -no-integrated-as 43.if ${COMPILER_VERSION} < 30500 44# XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives 45CLANG_NO_IAS34= -no-integrated-as 46.endif 47.endif 48 49.if ${COMPILER_TYPE} == "gcc" 50.if ${COMPILER_VERSION} >= 40800 51# Catch-all for all the things that are in our tree, but for which we're 52# not yet ready for this compiler. 53NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable 54CWARNEXTRA?= -Wno-error=address \ 55 -Wno-error=aggressive-loop-optimizations \ 56 -Wno-error=array-bounds \ 57 -Wno-error=attributes \ 58 -Wno-error=cast-qual \ 59 -Wno-error=enum-compare \ 60 -Wno-error=inline \ 61 -Wno-error=maybe-uninitialized \ 62 -Wno-error=overflow \ 63 -Wno-error=sequence-point \ 64 -Wno-error=unused-but-set-variable 65.if ${COMPILER_VERSION} >= 60100 66CWARNEXTRA+= -Wno-error=misleading-indentation \ 67 -Wno-error=nonnull-compare \ 68 -Wno-error=shift-overflow \ 69 -Wno-error=tautological-compare 70.endif 71.if ${COMPILER_VERSION} >= 70200 72CWARNEXTRA+= -Wno-error=memset-elt-size 73.endif 74.if ${COMPILER_VERSION} >= 80000 75CWARNEXTRA+= -Wno-error=packed-not-aligned 76.endif 77.else 78# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 79CWARNEXTRA?= -Wno-uninitialized 80# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for 81# the few files that are already known to generate cast-qual warnings. 82NO_WCAST_QUAL= -Wno-cast-qual 83.endif 84.endif 85 86# External compilers may not support our format extensions. Allow them 87# to be disabled. WARNING: format checking is disabled in this case. 88.if ${MK_FORMAT_EXTENSIONS} == "no" 89FORMAT_EXTENSIONS= -Wno-format 90.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 91FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 92.else 93FORMAT_EXTENSIONS= -fformat-extensions 94.endif 95 96# 97# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 98# and above adds code to the entry and exit point of every function to align the 99# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 100# per function call. While the 16-byte alignment may benefit micro benchmarks, 101# it is probably an overall loss as it makes the code bigger (less efficient 102# use of code cache tag lines) and uses more stack (less efficient use of data 103# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 104# operations inside the kernel itself. These operations are exclusively 105# reserved for user applications. 106# 107# gcc: 108# Setting -mno-mmx implies -mno-3dnow 109# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 110# 111# clang: 112# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 113# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 114# 115.if ${MACHINE_CPUARCH} == "i386" 116CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 117CFLAGS.clang+= -mno-aes -mno-avx 118CFLAGS+= -mno-mmx -mno-sse -msoft-float 119INLINE_LIMIT?= 8000 120.endif 121 122.if ${MACHINE_CPUARCH} == "arm" 123INLINE_LIMIT?= 8000 124.endif 125 126.if ${MACHINE_CPUARCH} == "aarch64" 127# We generally don't want fpu instructions in the kernel. 128CFLAGS += -mgeneral-regs-only 129# Reserve x18 for pcpu data 130CFLAGS += -ffixed-x18 131INLINE_LIMIT?= 8000 132.endif 133 134.if ${MACHINE_CPUARCH} == "riscv" 135CFLAGS.gcc+= -mcmodel=medany -march=rv64imafd -mabi=lp64 136INLINE_LIMIT?= 8000 137.endif 138 139# 140# For sparc64 we want the medany code model so modules may be located 141# anywhere in the 64-bit address space. We also tell GCC to use floating 142# point emulation. This avoids using floating point registers for integer 143# operations which it has a tendency to do. 144# 145.if ${MACHINE_CPUARCH} == "sparc64" 146CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 147CFLAGS.gcc+= -mcmodel=medany -msoft-float 148INLINE_LIMIT?= 15000 149.endif 150 151# 152# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 153# operations inside the kernel itself. These operations are exclusively 154# reserved for user applications. 155# 156# gcc: 157# Setting -mno-mmx implies -mno-3dnow 158# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 159# 160# clang: 161# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 162# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 163# (-mfpmath= is not supported) 164# 165.if ${MACHINE_CPUARCH} == "amd64" 166CFLAGS.clang+= -mno-aes -mno-avx 167CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 168 -fno-asynchronous-unwind-tables 169INLINE_LIMIT?= 8000 170.endif 171 172# 173# For PowerPC we tell gcc to use floating point emulation. This avoids using 174# floating point registers for integer operations which it has a tendency to do. 175# Also explicitly disable Altivec instructions inside the kernel. 176# 177.if ${MACHINE_CPUARCH} == "powerpc" 178CFLAGS+= -mno-altivec -msoft-float 179INLINE_LIMIT?= 15000 180.endif 181 182.if ${MACHINE_ARCH} == "powerpcspe" 183CFLAGS.gcc+= -mno-spe 184.endif 185 186# 187# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 188# DDB happy. ELFv2, if available, has some other efficiency benefits. 189# 190.if ${MACHINE_ARCH} == "powerpc64" 191.if ${COMPILER_VERSION} >= 40900 192CFLAGS.gcc+= -mabi=elfv2 193.else 194CFLAGS.gcc+= -mcall-aixdesc 195.endif 196CFLAGS.clang+= -mabi=elfv2 197.endif 198 199# 200# For MIPS we also tell gcc to use floating point emulation 201# 202.if ${MACHINE_CPUARCH} == "mips" 203CFLAGS+= -msoft-float 204INLINE_LIMIT?= 8000 205.endif 206 207# 208# GCC 3.0 and above like to do certain optimizations based on the 209# assumption that the program is linked against libc. Stop this. 210# 211CFLAGS+= -ffreestanding 212 213# 214# The C standard leaves signed integer overflow behavior undefined. 215# gcc and clang opimizers take advantage of this. The kernel makes 216# use of signed integer wraparound mechanics so we need the compiler 217# to treat it as a wraparound and not take shortcuts. 218# 219CFLAGS+= -fwrapv 220 221# 222# GCC SSP support 223# 224.if ${MK_SSP} != "no" && \ 225 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 226CFLAGS+= -fstack-protector 227.endif 228 229# 230# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 231# 232.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 233 ${MK_KERNEL_RETPOLINE} != "no" 234CFLAGS+= -mretpoline 235.endif 236 237# 238# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 239# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 240# cope well with DWARF 4, so force it to genereate DWARF2, which they 241# understand. Do this unconditionally as it is harmless when not needed, 242# but critical for these newer versions. 243# 244.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 245CFLAGS+= -gdwarf-2 246.endif 247 248CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 249CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 250 251# Tell bmake not to mistake standard targets for things to be searched for 252# or expect to ever be up-to-date. 253PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 254 beforelinking build build-tools buildfiles buildincludes \ 255 checkdpadd clean cleandepend cleandir cleanobj configure \ 256 depend distclean distribute exe \ 257 html includes install installfiles installincludes \ 258 obj objlink objs objwarn \ 259 realinstall regress \ 260 tags whereobj 261 262.PHONY: ${PHONY_NOTMAIN} 263.NOTMAIN: ${PHONY_NOTMAIN} 264 265CSTD= c99 266 267.if ${CSTD} == "k&r" 268CFLAGS+= -traditional 269.elif ${CSTD} == "c89" || ${CSTD} == "c90" 270CFLAGS+= -std=iso9899:1990 271.elif ${CSTD} == "c94" || ${CSTD} == "c95" 272CFLAGS+= -std=iso9899:199409 273.elif ${CSTD} == "c99" 274CFLAGS+= -std=iso9899:1999 275.else # CSTD 276CFLAGS+= -std=${CSTD} 277.endif # CSTD 278 279# Set target-specific linker emulation name. 280LD_EMULATION_aarch64=aarch64elf 281LD_EMULATION_amd64=elf_x86_64_fbsd 282LD_EMULATION_arm=armelf_fbsd 283LD_EMULATION_armv6=armelf_fbsd 284LD_EMULATION_armv7=armelf_fbsd 285LD_EMULATION_i386=elf_i386_fbsd 286LD_EMULATION_mips= elf32btsmip_fbsd 287LD_EMULATION_mipshf= elf32btsmip_fbsd 288LD_EMULATION_mips64= elf64btsmip_fbsd 289LD_EMULATION_mips64hf= elf64btsmip_fbsd 290LD_EMULATION_mipsel= elf32ltsmip_fbsd 291LD_EMULATION_mipselhf= elf32ltsmip_fbsd 292LD_EMULATION_mips64el= elf64ltsmip_fbsd 293LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 294LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 295LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 296LD_EMULATION_powerpc= elf32ppc_fbsd 297LD_EMULATION_powerpcspe= elf32ppc_fbsd 298LD_EMULATION_powerpc64= elf64ppc_fbsd 299LD_EMULATION_riscv64= elf64lriscv 300LD_EMULATION_sparc64= elf64_sparc_fbsd 301LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 302