# $FreeBSD$ # # 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 \ -Wno-unknown-pragmas \ ${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_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow NO_WSELF_ASSIGN= -Wno-self-assign NO_WUNNEEDED_INTERNAL_DECL= -Wno-unneeded-internal-declaration NO_WSOMETIMES_UNINITIALIZED= -Wno-error-sometimes-uninitialized NO_WCAST_QUAL= -Wno-cast-qual # 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 \ -Wno-error-pointer-sign .if ${COMPILER_VERSION} >= 30700 CWARNEXTRA+= -Wno-error-shift-negative-value .endif CLANG_NO_IAS= -no-integrated-as .if ${COMPILER_VERSION} < 30500 # XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives CLANG_NO_IAS34= -no-integrated-as .endif .endif .if ${COMPILER_TYPE} == "gcc" .if ${COMPILER_VERSION} >= 40800 # Catch-all for all the things that are in our tree, but for which we're # not yet ready for this compiler. CWARNEXTRA?= -Wno-error=address \ -Wno-error=aggressive-loop-optimizations \ -Wno-error=array-bounds \ -Wno-error=attributes \ -Wno-error=cast-qual \ -Wno-error=enum-compare \ -Wno-error=inline \ -Wno-error=maybe-uninitialized \ -Wno-error=overflow \ -Wno-error=sequence-point \ -Wno-error=strict-overflow \ -Wno-error=unused-but-set-variable .if ${COMPILER_VERSION} >= 60100 CWARNEXTRA+= -Wno-error=misleading-indentation \ -Wno-error=nonnull-compare \ -Wno-error=shift-overflow \ -Wno-error=tautological-compare .endif .else # For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. CWARNEXTRA?= -Wno-uninitialized .endif .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 .elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ .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 .if ${MACHINE_CPUARCH} == "aarch64" # We generally don't want fpu instructions in the kernel. CFLAGS += -mgeneral-regs-only # Reserve x18 for pcpu data CFLAGS += -ffixed-x18 .endif .if ${MACHINE_CPUARCH} == "riscv" CFLAGS.gcc+= -mcmodel=medany 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+= -mno-altivec CFLAGS.clang+= -mllvm -disable-ppc-float-in-variadic=true CFLAGS.gcc+= -msoft-float INLINE_LIMIT?= 15000 .endif # # Use dot symbols on powerpc64 to make ddb happy # .if ${MACHINE_ARCH} == "powerpc64" CFLAGS.gcc+= -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 # # The C standard leaves signed integer overflow behavior undefined. # gcc and clang opimizers take advantage of this. The kernel makes # use of signed integer wraparound mechanics so we need the compiler # to treat it as a wraparound and not take shortcuts. # CFLAGS+= -fwrapv # # 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 CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} # 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 distclean distribute exe \ html includes install installfiles installincludes lint \ obj objlink objs objwarn \ realinstall regress \ tags whereobj .PHONY: ${PHONY_NOTMAIN} .NOTMAIN: ${PHONY_NOTMAIN} CSTD= c99 .if ${CSTD} == "k&r" CFLAGS+= -traditional .elif ${CSTD} == "c89" || ${CSTD} == "c90" CFLAGS+= -std=iso9899:1990 .elif ${CSTD} == "c94" || ${CSTD} == "c95" CFLAGS+= -std=iso9899:199409 .elif ${CSTD} == "c99" CFLAGS+= -std=iso9899:1999 .else # CSTD CFLAGS+= -std=${CSTD} .endif # CSTD