d01fe93c3d
Clang 13.0.0 now has a -Wunused-but-set-variable warning similar to the
one gcc has had for quite a while. Since this triggers *very* often for
our kernel builds, don't make it a hard error, but leave the warning
visible so is some incentive to fix the instances.
(cherry picked from commit 395d46caae)
326 lines
11 KiB
Makefile
326 lines
11 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 -Wcast-qual \
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-Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
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-Wmissing-include-dirs -fdiagnostics-show-option \
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-Wno-unknown-pragmas \
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${CWARNEXTRA}
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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 ${COMPILER_TYPE} == "clang"
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NO_WCONSTANT_CONVERSION= -Wno-error=constant-conversion
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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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NO_WSELF_ASSIGN= -Wno-self-assign
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NO_WUNNEEDED_INTERNAL_DECL= -Wno-error=unneeded-internal-declaration
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NO_WSOMETIMES_UNINITIALIZED= -Wno-error=sometimes-uninitialized
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NO_WCAST_QUAL= -Wno-error=cast-qual
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NO_WTAUTOLOGICAL_POINTER_COMPARE= -Wno-tautological-pointer-compare
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.if ${COMPILER_VERSION} >= 100000
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NO_WMISLEADING_INDENTATION= -Wno-misleading-indentation
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.endif
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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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CWARNEXTRA?= -Wno-error=tautological-compare -Wno-error=empty-body \
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-Wno-error=parentheses-equality -Wno-error=unused-function \
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-Wno-error=pointer-sign
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CWARNEXTRA+= -Wno-error=shift-negative-value
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CWARNEXTRA+= -Wno-address-of-packed-member
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.if ${COMPILER_VERSION} >= 130000
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CWARNFLAGS+= -Wno-error=unused-but-set-variable
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.endif
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.endif # clang
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.if ${COMPILER_TYPE} == "gcc"
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# Catch-all for all the things that are in our tree, but for which we're
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# not yet ready for this compiler.
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NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable
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CWARNEXTRA?= -Wno-error=address \
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-Wno-error=aggressive-loop-optimizations \
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-Wno-error=array-bounds \
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-Wno-error=attributes \
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-Wno-error=cast-qual \
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-Wno-error=enum-compare \
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-Wno-error=maybe-uninitialized \
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-Wno-error=misleading-indentation \
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-Wno-error=nonnull-compare \
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-Wno-error=overflow \
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-Wno-error=sequence-point \
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-Wno-error=shift-overflow \
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-Wno-error=tautological-compare \
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-Wno-unused-but-set-variable
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.if ${COMPILER_VERSION} >= 70100
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CWARNEXTRA+= -Wno-error=stringop-overflow
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.endif
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.if ${COMPILER_VERSION} >= 70200
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CWARNEXTRA+= -Wno-error=memset-elt-size
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.endif
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.if ${COMPILER_VERSION} >= 80000
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CWARNEXTRA+= -Wno-error=packed-not-aligned
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.endif
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.if ${COMPILER_VERSION} >= 90100
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CWARNEXTRA+= -Wno-address-of-packed-member
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.endif
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.endif # gcc
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# This warning is utter nonsense
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CWARNFLAGS+= -Wno-format-zero-length
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# External compilers may not support our format extensions. Allow them
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# to be disabled. WARNING: format checking is disabled in this case.
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.if ${MK_FORMAT_EXTENSIONS} == "no"
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FORMAT_EXTENSIONS= -Wno-format
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.elif ${COMPILER_TYPE} == "clang"
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FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__
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.else
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FORMAT_EXTENSIONS= -fformat-extensions
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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 and -mno-3dnowa
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# Setting -mno-sse implies -mno-sse2, -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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CFLAGS.gcc+= -mpreferred-stack-boundary=2
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CFLAGS.clang+= -mno-aes -mno-avx
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CFLAGS+= -mno-mmx -mno-sse -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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.if ${MACHINE_CPUARCH} == "aarch64"
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# We generally don't want fpu instructions in the kernel.
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CFLAGS += -mgeneral-regs-only
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# Reserve x18 for pcpu data
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CFLAGS += -ffixed-x18
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INLINE_LIMIT?= 8000
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.endif
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#
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# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating
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# point registers within the kernel. However, for kernels supporting hardware
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# float (FPE), we have to include that in the march so we can have limited
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# floating point support in context switching needed for that. This is different
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# than userland where we use a hard-float ABI (lp64d).
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#
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# We also specify the "medium" code model, which generates code suitable for a
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# 2GiB addressing range located at any offset, allowing modules to be located
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# anywhere in the 64-bit address space. Note that clang and GCC refer to this
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# code model as "medium" and "medany" respectively.
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#
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.if ${MACHINE_CPUARCH} == "riscv"
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CFLAGS+= -march=rv64imafdc
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CFLAGS+= -mabi=lp64
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CFLAGS.clang+= -mcmodel=medium
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CFLAGS.gcc+= -mcmodel=medany
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INLINE_LIMIT?= 8000
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.if ${LINKER_FEATURES:Mriscv-relaxations} == ""
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CFLAGS+= -mno-relax
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.endif
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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 and -mno-3dnowa
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# Setting -mno-sse implies -mno-sse2, -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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CFLAGS.clang+= -mno-aes -mno-avx
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CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -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+= -mno-altivec -msoft-float
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INLINE_LIMIT?= 15000
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.endif
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.if ${MACHINE_ARCH} == "powerpcspe"
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CFLAGS.gcc+= -mno-spe
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.endif
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#
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# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make
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# DDB happy. ELFv2, if available, has some other efficiency benefits.
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#
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.if ${MACHINE_ARCH:Mpowerpc64*} != ""
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CFLAGS+= -mabi=elfv2
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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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# The C standard leaves signed integer overflow behavior undefined.
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# gcc and clang opimizers take advantage of this. The kernel makes
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# use of signed integer wraparound mechanics so we need the compiler
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# to treat it as a wraparound and not take shortcuts.
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#
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CFLAGS+= -fwrapv
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#
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# GCC SSP support
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#
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.if ${MK_SSP} != "no"
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CFLAGS+= -fstack-protector
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.endif
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#
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# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715)
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#
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.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \
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${MK_KERNEL_RETPOLINE} != "no"
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CFLAGS+= -mretpoline
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.endif
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#
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# Initialize stack variables on function entry
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#
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.if ${MK_INIT_ALL_ZERO} == "yes"
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.if ${COMPILER_FEATURES:Minit-all}
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CFLAGS+= -ftrivial-auto-var-init=zero \
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-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
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.else
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.warning InitAll (zeros) requested but not support by compiler
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.endif
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.elif ${MK_INIT_ALL_PATTERN} == "yes"
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.if ${COMPILER_FEATURES:Minit-all}
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CFLAGS+= -ftrivial-auto-var-init=pattern
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.else
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.warning InitAll (pattern) requested but not support by compiler
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.endif
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.endif
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CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}}
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CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}}
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CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}}
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# Tell bmake not to mistake standard targets for things to be searched for
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# or expect to ever be up-to-date.
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PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \
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beforelinking build build-tools buildfiles buildincludes \
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checkdpadd clean cleandepend cleandir cleanobj configure \
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depend distclean distribute exe \
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html includes install installfiles installincludes \
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obj objlink objs objwarn \
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realinstall regress \
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tags whereobj
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.PHONY: ${PHONY_NOTMAIN}
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.NOTMAIN: ${PHONY_NOTMAIN}
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CSTD= c99
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.if ${CSTD} == "k&r"
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CFLAGS+= -traditional
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.elif ${CSTD} == "c89" || ${CSTD} == "c90"
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CFLAGS+= -std=iso9899:1990
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.elif ${CSTD} == "c94" || ${CSTD} == "c95"
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CFLAGS+= -std=iso9899:199409
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.elif ${CSTD} == "c99"
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CFLAGS+= -std=iso9899:1999
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.else # CSTD
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CFLAGS+= -std=${CSTD}
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.endif # CSTD
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# Please keep this if in sync with bsd.sys.mk
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.if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld")
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# Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld".
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.if ${COMPILER_TYPE} == "clang"
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# Note: Clang does not like relative paths for ld so we map ld.lld -> lld.
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.if ${COMPILER_VERSION} >= 120000
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CCLDFLAGS+= --ld-path=${LD:[1]:S/^ld.//1W}
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.else
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CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W}
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.endif
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.else
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# GCC does not support an absolute path for -fuse-ld so we just print this
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# warning instead and let the user add the required symlinks.
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# However, we can avoid this warning if -B is set appropriately (e.g. for
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# CROSS_TOOLCHAIN=...-gcc).
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.if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/})
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.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported
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.endif
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.endif
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.endif
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# Set target-specific linker emulation name.
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LD_EMULATION_aarch64=aarch64elf
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LD_EMULATION_amd64=elf_x86_64_fbsd
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LD_EMULATION_arm=armelf_fbsd
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LD_EMULATION_armv6=armelf_fbsd
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LD_EMULATION_armv7=armelf_fbsd
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LD_EMULATION_i386=elf_i386_fbsd
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LD_EMULATION_mips= elf32btsmip_fbsd
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LD_EMULATION_mipshf= elf32btsmip_fbsd
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LD_EMULATION_mips64= elf64btsmip_fbsd
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LD_EMULATION_mips64hf= elf64btsmip_fbsd
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LD_EMULATION_mipsel= elf32ltsmip_fbsd
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LD_EMULATION_mipselhf= elf32ltsmip_fbsd
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LD_EMULATION_mips64el= elf64ltsmip_fbsd
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LD_EMULATION_mips64elhf= elf64ltsmip_fbsd
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LD_EMULATION_mipsn32= elf32btsmipn32_fbsd
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LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works
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LD_EMULATION_powerpc= elf32ppc_fbsd
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LD_EMULATION_powerpcspe= elf32ppc_fbsd
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LD_EMULATION_powerpc64= elf64ppc_fbsd
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LD_EMULATION_powerpc64le= elf64lppc_fbsd
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LD_EMULATION_riscv64= elf64lriscv
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LD_EMULATION_riscv64sf= elf64lriscv
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LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}}
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