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 ${NO_WFORMAT} 34.endif 35 36# External compilers may not support our format extensions. Allow them 37# to be disabled. WARNING: format checking is disabled in this case. 38.if ${MK_FORMAT_EXTENSIONS} == "no" 39NO_WFORMAT= -Wno-format 40.else 41FORMAT_EXTENSIONS= -fformat-extensions 42.endif 43 44# 45# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 46# and above adds code to the entry and exit point of every function to align the 47# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 48# per function call. While the 16-byte alignment may benefit micro benchmarks, 49# it is probably an overall loss as it makes the code bigger (less efficient 50# use of code cache tag lines) and uses more stack (less efficient use of data 51# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 52# operations inside the kernel itself. These operations are exclusively 53# reserved for user applications. 54# 55# gcc: 56# Setting -mno-mmx implies -mno-3dnow 57# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 58# 59# clang: 60# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 61# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 62# 63.if ${MACHINE_CPUARCH} == "i386" 64CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 65CFLAGS.clang+= -mno-aes -mno-avx 66CFLAGS+= -mno-mmx -mno-sse -msoft-float 67INLINE_LIMIT?= 8000 68.endif 69 70.if ${MACHINE_CPUARCH} == "arm" 71INLINE_LIMIT?= 8000 72.endif 73 74# 75# For sparc64 we want the medany code model so modules may be located 76# anywhere in the 64-bit address space. We also tell GCC to use floating 77# point emulation. This avoids using floating point registers for integer 78# operations which it has a tendency to do. 79# 80.if ${MACHINE_CPUARCH} == "sparc64" 81CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 82CFLAGS.gcc+= -mcmodel=medany -msoft-float 83INLINE_LIMIT?= 15000 84.endif 85 86# 87# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 88# operations inside the kernel itself. These operations are exclusively 89# reserved for user applications. 90# 91# gcc: 92# Setting -mno-mmx implies -mno-3dnow 93# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 94# 95# clang: 96# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 97# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 98# (-mfpmath= is not supported) 99# 100.if ${MACHINE_CPUARCH} == "amd64" 101CFLAGS.clang+= -mno-aes -mno-avx 102CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 103 -fno-asynchronous-unwind-tables 104INLINE_LIMIT?= 8000 105.endif 106 107# 108# For PowerPC we tell gcc to use floating point emulation. This avoids using 109# floating point registers for integer operations which it has a tendency to do. 110# Also explicitly disable Altivec instructions inside the kernel. 111# 112.if ${MACHINE_CPUARCH} == "powerpc" 113CFLAGS+= -msoft-float -mno-altivec 114INLINE_LIMIT?= 15000 115.endif 116 117# 118# Use dot symbols on powerpc64 to make ddb happy 119# 120.if ${MACHINE_ARCH} == "powerpc64" 121CFLAGS+= -mcall-aixdesc 122.endif 123 124# 125# For MIPS we also tell gcc to use floating point emulation 126# 127.if ${MACHINE_CPUARCH} == "mips" 128CFLAGS+= -msoft-float 129INLINE_LIMIT?= 8000 130.endif 131 132# 133# GCC 3.0 and above like to do certain optimizations based on the 134# assumption that the program is linked against libc. Stop this. 135# 136CFLAGS+= -ffreestanding 137 138# 139# GCC SSP support 140# 141.if ${MK_SSP} != "no" && \ 142 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 143CFLAGS+= -fstack-protector 144.endif 145 146# 147# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 148# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 149# cope well with DWARF 4, so force it to genereate DWARF2, which they 150# understand. Do this unconditionally as it is harmless when not needed, 151# but critical for these newer versions. 152# 153.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 154CFLAGS+= -gdwarf-2 155.endif 156 157CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} 158