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 ${CWARNEXTRA} 11# 12# The following flags are next up for working on: 13# -Wextra 14 15# Disable a few warnings for clang, since there are several places in the 16# kernel where fixing them is more trouble than it is worth, or where there is 17# a false positive. 18.if ${COMPILER_TYPE} == "clang" 19NO_WCONSTANT_CONVERSION= -Wno-constant-conversion 20NO_WARRAY_BOUNDS= -Wno-array-bounds 21NO_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative 22NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow 23NO_WUNUSED_VALUE= -Wno-unused-value 24NO_WSELF_ASSIGN= -Wno-self-assign 25NO_WFORMAT_SECURITY= -Wno-format-security 26NO_WUNNEEDED_INTERNAL_DECL= -Wno-unneeded-internal-declaration 27NO_WSOMETIMES_UNINITIALIZED= -Wno-error-sometimes-uninitialized 28# Several other warnings which might be useful in some cases, but not severe 29# enough to error out the whole kernel build. Display them anyway, so there is 30# some incentive to fix them eventually. 31CWARNEXTRA?= -Wno-error-tautological-compare -Wno-error-empty-body \ 32 -Wno-error-parentheses-equality -Wno-error-unused-function 33.endif 34 35.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 40300 36# Catch-all for all the things that are in our tree, but for which we're 37# not yet ready for this compiler. Note: we likely only really "support" 38# building with gcc 4.8 and newer. Nothing older has been tested. 39CWARNEXTRA?= -Wno-error=inline -Wno-error=enum-compare -Wno-error=unused-but-set-variable \ 40 -Wno-error=aggressive-loop-optimizations -Wno-error=maybe-uninitialized \ 41 -Wno-error=array-bounds -Wno-error=address \ 42 -Wno-error=cast-qual -Wno-error=sequence-point -Wno-error=attributes \ 43 -Wno-error=strict-overflow -Wno-error=overflow 44.endif 45 46# External compilers may not support our format extensions. Allow them 47# to be disabled. WARNING: format checking is disabled in this case. 48.if ${MK_FORMAT_EXTENSIONS} == "no" 49FORMAT_EXTENSIONS= -Wno-format 50.else 51FORMAT_EXTENSIONS= -fformat-extensions 52.endif 53 54# 55# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 56# and above adds code to the entry and exit point of every function to align the 57# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 58# per function call. While the 16-byte alignment may benefit micro benchmarks, 59# it is probably an overall loss as it makes the code bigger (less efficient 60# use of code cache tag lines) and uses more stack (less efficient use of data 61# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 62# operations inside the kernel itself. These operations are exclusively 63# reserved for user applications. 64# 65# gcc: 66# Setting -mno-mmx implies -mno-3dnow 67# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 68# 69# clang: 70# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 71# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 72# 73.if ${MACHINE_CPUARCH} == "i386" 74CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 75CFLAGS.clang+= -mno-aes -mno-avx 76CFLAGS+= -mno-mmx -mno-sse -msoft-float 77INLINE_LIMIT?= 8000 78.endif 79 80.if ${MACHINE_CPUARCH} == "arm" 81INLINE_LIMIT?= 8000 82.endif 83 84# 85# For sparc64 we want the medany code model so modules may be located 86# anywhere in the 64-bit address space. We also tell GCC to use floating 87# point emulation. This avoids using floating point registers for integer 88# operations which it has a tendency to do. 89# 90.if ${MACHINE_CPUARCH} == "sparc64" 91CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 92CFLAGS.gcc+= -mcmodel=medany -msoft-float 93INLINE_LIMIT?= 15000 94.endif 95 96# 97# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 98# operations inside the kernel itself. These operations are exclusively 99# reserved for user applications. 100# 101# gcc: 102# Setting -mno-mmx implies -mno-3dnow 103# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 104# 105# clang: 106# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 107# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 108# (-mfpmath= is not supported) 109# 110.if ${MACHINE_CPUARCH} == "amd64" 111CFLAGS.clang+= -mno-aes -mno-avx 112CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 113 -fno-asynchronous-unwind-tables 114INLINE_LIMIT?= 8000 115.endif 116 117# 118# For PowerPC we tell gcc to use floating point emulation. This avoids using 119# floating point registers for integer operations which it has a tendency to do. 120# Also explicitly disable Altivec instructions inside the kernel. 121# 122.if ${MACHINE_CPUARCH} == "powerpc" 123CFLAGS+= -msoft-float -mno-altivec 124INLINE_LIMIT?= 15000 125.endif 126 127# 128# Use dot symbols on powerpc64 to make ddb happy 129# 130.if ${MACHINE_ARCH} == "powerpc64" 131CFLAGS+= -mcall-aixdesc 132.endif 133 134# 135# For MIPS we also tell gcc to use floating point emulation 136# 137.if ${MACHINE_CPUARCH} == "mips" 138CFLAGS+= -msoft-float 139INLINE_LIMIT?= 8000 140.endif 141 142# 143# GCC 3.0 and above like to do certain optimizations based on the 144# assumption that the program is linked against libc. Stop this. 145# 146CFLAGS+= -ffreestanding 147 148# 149# GCC SSP support 150# 151.if ${MK_SSP} != "no" && \ 152 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 153CFLAGS+= -fstack-protector 154.endif 155 156# 157# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 158# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 159# cope well with DWARF 4, so force it to genereate DWARF2, which they 160# understand. Do this unconditionally as it is harmless when not needed, 161# but critical for these newer versions. 162# 163.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 164CFLAGS+= -gdwarf-2 165.endif 166 167CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} 168