1 # $FreeBSD: src/share/mk/bsd.kern.mk,v 1.17.2.1 2001/08/01 16:56:56 obrien Exp $
2 # $DragonFly: src/sys/conf/bsd.kern.mk,v 1.7 2006/03/24 18:35:28 dillon Exp $
5 # Warning flags for compiling the kernel and components of the kernel.
7 # Note that the newly added -Wcast-qual is responsible for generating
8 # most of the remaining warnings. Warnings introduced with -Wall will
9 # also pop up, but are easier to fix.
11 .if ${CCVER} == "gcc2"
12 CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
13 -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
14 -fformat-extensions -ansi
16 CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
17 -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
21 # The following flags are next up for working on:
24 # When working on removing warnings from code, the `-Werror' flag should be
25 # of material assistance.
29 # On the i386, do not align the stack to 16-byte boundaries. Otherwise GCC
30 # 2.95 adds code to the entry and exit point of every function to align the
31 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
32 # per function call. While the 16-byte alignment may benefit micro benchmarks,
33 # it is probably an overall loss as it makes the code bigger (less efficient
34 # use of code cache tag lines) and uses more stack (less efficient use of data
37 # Prohibit the use of FP registers in the kernel. The user FP state is
38 # only saved and restored under strictly managed conditions and mainline
39 # kernel code cannot safely use the FP system.
41 .if ${MACHINE_ARCH} == "i386"
42 CFLAGS+= -mpreferred-stack-boundary=2
43 CFLAGS+= -fno-stack-protector
44 CFLAGS+= -mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3
48 # On the alpha, make sure that we don't use floating-point registers and
49 # allow the use of EV56 instructions (only needed for low-level i/o).
51 .if ${MACHINE_ARCH} == "alpha"
52 CFLAGS+= -mno-fp-regs -Wa,-mev56
55 # Require the proper use of 'extern' for variables. -fno-common will
56 # cause duplicate declarations to generate a link error.
60 # Prevent GCC 3.x from making certain libc based inline optimizations
62 CFLAGS+= -ffreestanding