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linux/scripts/Makefile.compiler
Nathan Chancellor 0ee695a471
kbuild: Add -Wa,--fatal-warnings to as-instr invocation
Certain assembler instruction tests may only induce warnings from the
assembler on an unsupported instruction or option, which causes as-instr
to succeed when it was expected to fail. Some tests workaround this
limitation by additionally testing that invalid input fails as expected.
However, this is fragile if the assembler is changed to accept the
invalid input, as it will cause the instruction/option to be unavailable
like it was unsupported even when it is.

Use '-Wa,--fatal-warnings' in the as-instr macro to turn these warnings
into hard errors, which avoids this fragility and makes tests more
robust and well formed.

Cc: stable@vger.kernel.org
Suggested-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Eric Biggers <ebiggers@google.com>
Tested-by: Andy Chiu <andybnac@gmail.com>
Reviewed-by: Andy Chiu <andybnac@gmail.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240125-fix-riscv-option-arch-llvm-18-v1-1-390ac9cc3cd0@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-02-16 16:07:07 -08:00

75 lines
2.7 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0-only
# cc-cross-prefix
# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
# Return first <prefix> where a <prefix>gcc is found in PATH.
# If no gcc found in PATH with listed prefixes return nothing
#
# Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
# would try to directly execute the shell builtin 'command'. This workaround
# should be kept for a long time since this issue was fixed only after the
# GNU Make 4.2.1 release.
cc-cross-prefix = $(firstword $(foreach c, $(1), \
$(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
# output directory for tests below
TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$
# try-run
# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
# Exit code chooses option. "$$TMP" serves as a temporary file and is
# automatically cleaned up.
try-run = $(shell set -e; \
TMP=$(TMPOUT)/tmp; \
trap "rm -rf $(TMPOUT)" EXIT; \
mkdir -p $(TMPOUT); \
if ($(1)) >/dev/null 2>&1; \
then echo "$(2)"; \
else echo "$(3)"; \
fi)
# as-option
# Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
as-option = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2))
# as-instr
# Usage: aflags-y += $(call as-instr,instr,option1,option2)
as-instr = $(call try-run,\
printf "%b\n" "$(1)" | $(CC) -Werror $(CLANG_FLAGS) $(KBUILD_AFLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3))
# __cc-option
# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
__cc-option = $(call try-run,\
$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
# cc-option
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
cc-option = $(call __cc-option, $(CC),\
$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS),$(1),$(2))
# cc-option-yn
# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
cc-option-yn = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
# cc-disable-warning
# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
cc-disable-warning = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
# gcc-min-version
# Usage: cflags-$(call gcc-min-version, 70100) += -foo
gcc-min-version = $(call test-ge, $(CONFIG_GCC_VERSION), $1)
# clang-min-version
# Usage: cflags-$(call clang-min-version, 110000) += -foo
clang-min-version = $(call test-ge, $(CONFIG_CLANG_VERSION), $1)
# ld-option
# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))