freebsd/sys/conf/kern.mk

# $FreeBSD$

#
# Warning flags for compiling the kernel and components of the kernel.
#
# Note that the newly added -Wcast-qual is responsible for generating 
# most of the remaining warnings.  Warnings introduced with -Wall will
# also pop up, but are easier to fix.
.if ${CC:T:Micc} == "icc"
#CWARNFLAGS=	-w2	# use this if you are terribly bored
CWARNFLAGS=
.else
CWARNFLAGS?=	-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
		-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
		-Wundef -Wno-pointer-sign -fformat-extensions
.endif
#
# The following flags are next up for working on:
#	-W

#
# On the i386, do not align the stack to 16-byte boundaries.  Otherwise GCC
# 2.95 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 SSE and other SIMD
# operations inside the kernel itself.  These operations are exclusively
# reserved for user applications.
#
.if ${MACHINE_CPUARCH} == "i386" && ${CC:T:Micc} != "icc"
.if ${CC:T:Mclang} != "clang"
CFLAGS+=	-mno-align-long-strings -mpreferred-stack-boundary=2
.endif
CFLAGS+=	-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -msoft-float
INLINE_LIMIT?=	8000
.endif

.if ${MACHINE_CPUARCH} == "arm"
INLINE_LIMIT?=	8000
.endif
#
# For IA-64, we use r13 for the kernel globals pointer and we only use
# a very small subset of float registers for integer divides.
#
.if ${MACHINE_CPUARCH} == "ia64"
CFLAGS+=	-ffixed-r13 -mfixed-range=f32-f127 -fpic #-mno-sdata
INLINE_LIMIT?=	15000
.endif

#
# For sparc64 we want medlow code model, and we 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+=	-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.
#
.if ${MACHINE_CPUARCH} == "amd64"
CFLAGS+=	-mcmodel=kernel -mno-red-zone \
		-mfpmath=387 -mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 \
		-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+=	-msoft-float -mno-altivec
INLINE_LIMIT?=	15000
.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.
#
.if ${CC:T:Micc} == "icc"
CFLAGS+=	-nolib_inline
.else
CFLAGS+=	-ffreestanding
.endif

.if ${CC:T:Micc} == "icc"
CFLAGS+=	-restrict
.endif

#
# GCC SSP support.
#
.if ${MK_SSP} != "no" && ${CC:T:Micc} != "icc" && \
    ${MACHINE_CPUARCH} != "ia64" && ${MACHINE_CPUARCH} != "arm" && \
    ${MACHINE_CPUARCH} != "mips"
CFLAGS+=	-fstack-protector
.endif

#
# Enable CTF conversation on request.
#
.if defined(WITH_CTF)
.undef NO_CTF
.endif