LXR linux/scripts/Makefile.compiler

   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. "$$TMP" serves as a temporary file and is
  21# automatically cleaned up.
  22try-run = $(shell set -e;               \
  23        TMP=$(TMPOUT)/tmp;              \
  24        mkdir -p $(TMPOUT);             \
  25        trap "rm -rf $(TMPOUT)" EXIT;   \
  26        if ($(1)) >/dev/null 2>&1;      \
  27        then echo "$(2)";               \
  28        else echo "$(3)";               \
  29        fi)
  30
  31# as-option
  32# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
  33
  34as-option = $(call try-run,\
  35        $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
  36
  37# as-instr
  38# Usage: cflags-y += $(call as-instr,instr,option1,option2)
  39
  40as-instr = $(call try-run,\
  41        printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -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 = $(call try-run,\
  57        $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
  58
  59# cc-disable-warning
  60# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
  61cc-disable-warning = $(call try-run,\
  62        $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
  63
  64# cc-ifversion
  65# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  66cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
  67
  68# ld-option
  69# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
  70ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
  71
  72# ld-ifversion
  73# Usage:  $(call ld-ifversion, -ge, 22252, y)
  74ld-ifversion = $(shell [ $(CONFIG_LD_VERSION)0 $(1) $(2)0 ] && echo $(3) || echo $(4))
  75