xref: /linux/scripts/Makefile.compiler (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1# SPDX-License-Identifier: GPL-2.0-only
2
3# cc-cross-prefix
4# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
5# Return first <prefix> where a <prefix>gcc is found in PATH.
6# If no gcc found in PATH with listed prefixes return nothing
7#
8# Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
9# would try to directly execute the shell builtin 'command'. This workaround
10# should be kept for a long time since this issue was fixed only after the
11# GNU Make 4.2.1 release.
12cc-cross-prefix = $(firstword $(foreach c, $(1), \
13			$(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
14
15# output directory for tests below
16TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$
17
18# try-run
19# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
20# Exit code chooses option. "$$TMP" serves as a temporary file and is
21# automatically cleaned up.
22try-run = $(shell set -e;		\
23	TMP=$(TMPOUT)/tmp;		\
24	trap "rm -rf $(TMPOUT)" EXIT;	\
25	mkdir -p $(TMPOUT);		\
26	if ($(1)) >/dev/null 2>&1;	\
27	then echo "$(2)";		\
28	else echo "$(3)";		\
29	fi)
30
31# as-option
32# Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
33
34as-option = $(call try-run,\
35	$(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2))
36
37# as-instr
38# Usage: aflags-y += $(call as-instr,instr,option1,option2)
39
40as-instr = $(call try-run,\
41	printf "%b\n" "$(1)" | $(CC) -Werror $(CLANG_FLAGS) $(KBUILD_AFLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3))
42
43# __cc-option
44# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
45__cc-option = $(call try-run,\
46	$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
47
48# cc-option
49# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
50
51cc-option = $(call __cc-option, $(CC),\
52	$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS),$(1),$(2))
53
54# cc-option-yn
55# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
56cc-option-yn = $(if $(call cc-option,$1),y,n)
57
58# cc-disable-warning
59# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
60cc-disable-warning = $(if $(call cc-option,-W$(strip $1)),-Wno-$(strip $1))
61
62# gcc-min-version
63# Usage: cflags-$(call gcc-min-version, 70100) += -foo
64gcc-min-version = $(call test-ge, $(CONFIG_GCC_VERSION), $1)
65
66# clang-min-version
67# Usage: cflags-$(call clang-min-version, 110000) += -foo
68clang-min-version = $(call test-ge, $(CONFIG_CLANG_VERSION), $1)
69
70# ld-option
71# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
72ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
73
74# __rustc-option
75# Usage: MY_RUSTFLAGS += $(call __rustc-option,$(RUSTC),$(MY_RUSTFLAGS),-Cinstrument-coverage,-Zinstrument-coverage)
76# TODO: remove RUSTC_BOOTSTRAP=1 when we raise the minimum GNU Make version to 4.4
77__rustc-option = $(call try-run,\
78	echo '#![allow(missing_docs)]#![feature(no_core)]#![no_core]' | RUSTC_BOOTSTRAP=1\
79	$(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null,$(2)) $(3)\
80	--crate-type=rlib --out-dir=$(TMPOUT) --emit=obj=- - >/dev/null,$(3),$(4))
81
82# rustc-option
83# Usage: rustflags-y += $(call rustc-option,-Cinstrument-coverage,-Zinstrument-coverage)
84rustc-option = $(call __rustc-option, $(RUSTC),\
85	$(KBUILD_RUSTFLAGS),$(1),$(2))
86
87# rustc-option-yn
88# Usage: flag := $(call rustc-option-yn,-Cinstrument-coverage)
89rustc-option-yn = $(if $(call rustc-option,$1),y,n)
90