linux/scripts/Makefile.compiler
Masahiro Yamada dd29865633 kbuild: set EXIT trap before creating temporary directory
Swap the order of 'mkdir' and 'trap' just in case the subshell is
interrupted between 'mkdir' and 'trap' although the effect might be
subtle.

This does not intend to make the cleanup perfect. There are more cases
that miss to remove the tmp directory, for example:

 - When interrupted, dash does not invoke the EXIT trap (bash does)

 - 'rm' command might be interrupted before removing the directory

I am not addressing all the cases since the tmp directory is harmless
after all.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-08-03 22:56:38 +09:00

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. "$$TMP" serves as a temporary file and is
# automatically cleaned up.
try-run = $(shell set -e; \
TMP=$(TMPOUT)/tmp; \
trap "rm -rf $(TMPOUT)" EXIT; \
mkdir -p $(TMPOUT); \
if ($(1)) >/dev/null 2>&1; \
then echo "$(2)"; \
else echo "$(3)"; \
fi)
# as-option
# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
as-option = $(call try-run,\
$(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
# as-instr
# Usage: cflags-y += $(call as-instr,instr,option1,option2)
as-instr = $(call try-run,\
printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -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)))
# cc-ifversion
# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
# ld-option
# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
# ld-ifversion
# Usage: $(call ld-ifversion, -ge, 22252, y)
ld-ifversion = $(shell [ $(CONFIG_LD_VERSION)0 $(1) $(2)0 ] && echo $(3) || echo $(4))