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mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-04 20:19:47 +08:00
linux/scripts/Makefile.compiler
Miguel Ojeda 1c4494c14b rust: kbuild: use pound to support GNU Make < 4.3
GNU Make 4.3 changed the behavior of `#` inside commands in commit
c6966b323811 ("[SV 20513] Un-escaped # are not comments in function
invocations"):

    * WARNING: Backward-incompatibility!
      Number signs (#) appearing inside a macro reference or function invocation
      no longer introduce comments and should not be escaped with backslashes:
      thus a call such as:
        foo := $(shell echo '#')
      is legal.  Previously the number sign needed to be escaped, for example:
        foo := $(shell echo '\#')
      Now this latter will resolve to "\#".  If you want to write makefiles
      portable to both versions, assign the number sign to a variable:
        H := \#
        foo := $(shell echo '$H')
      This was claimed to be fixed in 3.81, but wasn't, for some reason.
      To detect this change search for 'nocomment' in the .FEATURES variable.

Unlike other commits in the kernel about this issue, such as commit
633174a704 ("lib/raid6/test/Makefile: Use $(pound) instead of \#
for Make 4.3"), that fixed the issue for newer GNU Makes, in our case
it was the opposite, i.e. we need to fix it for the older ones: someone
building with e.g. 4.2.1 gets the following error:

    scripts/Makefile.compiler:81: *** unterminated call to function 'call': missing ')'.  Stop.

Thus use the existing variable to fix it.

Reported-by: moyi geek <1441339168@qq.com>
Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/291565/topic/x/near/512001985
Cc: stable@vger.kernel.org
Fixes: e72a076c62 ("kbuild: fix issues with rustc-option")
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250414171241.2126137-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-04-15 20:45:46 +02:00

94 lines
3.5 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 = .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 = $(if $(call cc-option,$1),y,n)
# cc-disable-warning
# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
cc-disable-warning = $(if $(call cc-option,-W$(strip $1)),-Wno-$(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), $1)
# rustc-min-version
# Usage: rustc-$(call rustc-min-version, 108500) += -Cfoo
rustc-min-version = $(call test-ge, $(CONFIG_RUSTC_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))
# __rustc-option
# Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage)
# TODO: remove RUSTC_BOOTSTRAP=1 when we raise the minimum GNU Make version to 4.4
__rustc-option = $(call try-run,\
echo '$(pound)![allow(missing_docs)]$(pound)![feature(no_core)]$(pound)![no_core]' | RUSTC_BOOTSTRAP=1\
$(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null --target=%,$(2)) $(3)\
--crate-type=rlib --out-dir=$(TMPOUT) --emit=obj=- - >/dev/null,$(3),$(4))
# rustc-option
# Usage: rustflags-y += $(call rustc-option,-Cinstrument-coverage,-Zinstrument-coverage)
rustc-option = $(call __rustc-option, $(RUSTC),\
$(KBUILD_RUSTFLAGS),$(1),$(2))
# rustc-option-yn
# Usage: flag := $(call rustc-option-yn,-Cinstrument-coverage)
rustc-option-yn = $(if $(call rustc-option,$1),y,n)