# SPDX-License-Identifier: GPL-2.0-only# Kconfig helper macros # Convenient variablescomma       := ,quote       := "squote      := 'empty       :=space       := $(empty) $(empty)dollar      := $right_paren := )left_paren  := ( # $(if-success,<command>,<then>,<else>)# Return <then> if <command> exits with 0, <else> otherwise.if-success = $(shell,{ $(1); } >/dev/null 2>&1 && echo "$(2)" || echo "$(3)") # $(success,<command>)# Return y if <command> exits with 0, n otherwisesuccess = $(if-success,$(1),y,n) # $(failure,<command>)# Return n if <command> exits with 0, y otherwisefailure = $(if-success,$(1),n,y) # $(cc-option,<flag>)# Return y if the compiler supports <flag>, n otherwisecc-option = $(success,$(CC) -Werror $(CLANG_FLAGS) $(1) -S -x c /dev/null -o /dev/null) # $(ld-option,<flag>)# Return y if the linker supports <flag>, n otherwiseld-option = $(success,$(LD) -v $(1)) # $(as-option,<flag>)# /dev/zero is used as output instead of /dev/null as some assembler cribs when# both input and output are same. Also both of them have same write behaviour so# can be easily substituted.as-option = $(success, $(CC) $(CLANG_FLAGS) $(1) -c -x assembler /dev/null -o /dev/zero) # $(as-instr,<instr>)# Return y if the assembler supports <instr>, n otherwiseas-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -) # check if $(CC) and $(LD) exist$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found) # Fail if the linker is gold as it's not capable of linking the kernel proper$(error-if,$(success, $(LD) -v | grep -q gold), gold linker '$(LD)' not supported) # machine bit flags#  $(m32-flag): -m32 if the compiler supports it, or an empty string otherwise.#  $(m64-flag): -m64 if the compiler supports it, or an empty string otherwise.cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))m32-flag := $(cc-option-bit,-m32)m64-flag := $(cc-option-bit,-m64)