0ed78d642e
might be useful in some cases, but which are not severe enough to error out the whole kernel build. Display them anyway, so there is at least some incentive to fix them eventually. Start with -Wtautological-compare warnings. These usually occur when people check if unsigned quantities are negative, or similar cases. To clean these up would be painful, and might give problems if the base type which is compared against changes to signed later on. MFC after: 1 week
143 lines
4.4 KiB
Makefile
143 lines
4.4 KiB
Makefile
# $FreeBSD$
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#
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# Warning flags for compiling the kernel and components of the kernel:
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#
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CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
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-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
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-Wundef -Wno-pointer-sign -fformat-extensions \
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-Wmissing-include-dirs -fdiagnostics-show-option
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#
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# The following flags are next up for working on:
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# -Wextra
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# Disable a few warnings for clang, since there are several places in the
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# kernel where fixing them is more trouble than it is worth, or where there is
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# a false positive.
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.if ${CC:T:Mclang} == "clang"
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NO_WCONSTANT_CONVERSION= -Wno-constant-conversion
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NO_WARRAY_BOUNDS= -Wno-array-bounds
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NO_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative
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NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow
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# Several other warnings which might be useful in some cases, but not severe
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# enough to error out the whole kernel build. Display them anyway, so there is
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# some incentive to fix them eventually.
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CWARNFLAGS+= -Wno-error-tautological-compare
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.endif
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#
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# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95
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# and above adds code to the entry and exit point of every function to align the
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# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
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# per function call. While the 16-byte alignment may benefit micro benchmarks,
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# it is probably an overall loss as it makes the code bigger (less efficient
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# use of code cache tag lines) and uses more stack (less efficient use of data
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# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD
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# operations inside the kernel itself. These operations are exclusively
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# reserved for user applications.
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#
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# gcc:
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# Setting -mno-mmx implies -mno-3dnow
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# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3
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#
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# clang:
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# Setting -mno-mmx implies -mno-3dnow, -mno-3dnowa, -mno-sse, -mno-sse2,
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# -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
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#
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.if ${MACHINE_CPUARCH} == "i386"
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.if ${CC:T:Mclang} != "clang"
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CFLAGS+= -mno-align-long-strings -mpreferred-stack-boundary=2 -mno-sse
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.else
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CFLAGS+= -mno-aes -mno-avx
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.endif
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CFLAGS+= -mno-mmx -msoft-float
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INLINE_LIMIT?= 8000
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.endif
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.if ${MACHINE_CPUARCH} == "arm"
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INLINE_LIMIT?= 8000
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.endif
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#
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# For IA-64, we use r13 for the kernel globals pointer and we only use
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# a very small subset of float registers for integer divides.
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#
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.if ${MACHINE_CPUARCH} == "ia64"
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CFLAGS+= -ffixed-r13 -mfixed-range=f32-f127 -fpic #-mno-sdata
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INLINE_LIMIT?= 15000
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.endif
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#
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# For sparc64 we want medlow code model, and we tell gcc to use floating
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# point emulation. This avoids using floating point registers for integer
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# operations which it has a tendency to do.
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#
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.if ${MACHINE_CPUARCH} == "sparc64"
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CFLAGS+= -mcmodel=medany -msoft-float
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INLINE_LIMIT?= 15000
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.endif
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#
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# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
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# operations inside the kernel itself. These operations are exclusively
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# reserved for user applications.
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#
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# gcc:
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# Setting -mno-mmx implies -mno-3dnow
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# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
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#
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# clang:
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# Setting -mno-mmx implies -mno-3dnow, -mno-3dnowa, -mno-sse, -mno-sse2,
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# -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
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# (-mfpmath= is not supported)
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#
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.if ${MACHINE_CPUARCH} == "amd64"
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.if ${CC:T:Mclang} != "clang"
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CFLAGS+= -mno-sse
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.else
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CFLAGS+= -mno-aes -mno-avx
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.endif
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CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -msoft-float \
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-fno-asynchronous-unwind-tables
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INLINE_LIMIT?= 8000
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.endif
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#
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# For PowerPC we tell gcc to use floating point emulation. This avoids using
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# floating point registers for integer operations which it has a tendency to do.
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# Also explicitly disable Altivec instructions inside the kernel.
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#
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.if ${MACHINE_CPUARCH} == "powerpc"
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CFLAGS+= -msoft-float -mno-altivec
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INLINE_LIMIT?= 15000
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.endif
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#
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# Use dot symbols on powerpc64 to make ddb happy
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#
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.if ${MACHINE_ARCH} == "powerpc64"
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CFLAGS+= -mcall-aixdesc
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.endif
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#
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# For MIPS we also tell gcc to use floating point emulation
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#
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.if ${MACHINE_CPUARCH} == "mips"
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CFLAGS+= -msoft-float
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INLINE_LIMIT?= 8000
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.endif
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#
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# GCC 3.0 and above like to do certain optimizations based on the
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# assumption that the program is linked against libc. Stop this.
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#
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CFLAGS+= -ffreestanding
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#
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# GCC SSP support
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#
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.if ${MK_SSP} != "no" && ${MACHINE_CPUARCH} != "ia64" && \
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${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
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CFLAGS+= -fstack-protector
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.endif
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