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1# SPDX-License-Identifier: GPL-2.02ifneq ($(O),)3ifeq ($(origin O), command line)4 $(if $(shell cd $(PWD); test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)5 ABSOLUTE_O := $(shell cd $(PWD); cd $(O) ; pwd)6 OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)7 COMMAND_O := O=$(ABSOLUTE_O)8ifeq ($(objtree),)9 objtree := $(O)10endif11endif12endif13 14# check that the output directory actually exists15ifneq ($(OUTPUT),)16OUTDIR := $(shell cd $(OUTPUT) && pwd)17$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))18endif19 20#21# Include saner warnings here, which can catch bugs:22#23EXTRA_WARNINGS := -Wbad-function-cast24EXTRA_WARNINGS += -Wdeclaration-after-statement25EXTRA_WARNINGS += -Wformat-security26EXTRA_WARNINGS += -Wformat-y2k27EXTRA_WARNINGS += -Winit-self28EXTRA_WARNINGS += -Wmissing-declarations29EXTRA_WARNINGS += -Wmissing-prototypes30EXTRA_WARNINGS += -Wnested-externs31EXTRA_WARNINGS += -Wno-system-headers32EXTRA_WARNINGS += -Wold-style-definition33EXTRA_WARNINGS += -Wpacked34EXTRA_WARNINGS += -Wredundant-decls35EXTRA_WARNINGS += -Wstrict-prototypes36EXTRA_WARNINGS += -Wswitch-default37EXTRA_WARNINGS += -Wswitch-enum38EXTRA_WARNINGS += -Wundef39EXTRA_WARNINGS += -Wwrite-strings40EXTRA_WARNINGS += -Wformat41EXTRA_WARNINGS += -Wno-type-limits42 43# Makefiles suck: This macro sets a default value of $(2) for the44# variable named by $(1), unless the variable has been set by45# environment or command line. This is necessary for CC and AR46# because make sets default values, so the simpler ?= approach47# won't work as expected.48define allow-override49 $(if $(or $(findstring environment,$(origin $(1))),\50 $(findstring command line,$(origin $(1)))),,\51 $(eval $(1) = $(2)))52endef53 54ifneq ($(LLVM),)55ifneq ($(filter %/,$(LLVM)),)56LLVM_PREFIX := $(LLVM)57else ifneq ($(filter -%,$(LLVM)),)58LLVM_SUFFIX := $(LLVM)59endif60 61$(call allow-override,CC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))62$(call allow-override,AR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX))63$(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX))64$(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX))65$(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX))66else67# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.68$(call allow-override,CC,$(CROSS_COMPILE)gcc)69$(call allow-override,AR,$(CROSS_COMPILE)ar)70$(call allow-override,LD,$(CROSS_COMPILE)ld)71$(call allow-override,CXX,$(CROSS_COMPILE)g++)72$(call allow-override,STRIP,$(CROSS_COMPILE)strip)73endif74 75CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)76 77ifneq ($(LLVM),)78HOSTAR ?= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)79HOSTCC ?= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)80HOSTLD ?= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)81else82HOSTAR ?= ar83HOSTCC ?= gcc84HOSTLD ?= ld85endif86 87# Some tools require Clang, LLC and/or LLVM utils88CLANG ?= clang89LLC ?= llc90LLVM_CONFIG ?= llvm-config91LLVM_OBJCOPY ?= llvm-objcopy92LLVM_STRIP ?= llvm-strip93 94ifeq ($(CC_NO_CLANG), 1)95EXTRA_WARNINGS += -Wstrict-aliasing=396 97else ifneq ($(CROSS_COMPILE),)98# Allow userspace to override CLANG_CROSS_FLAGS to specify their own99# sysroots and flags or to avoid the GCC call in pure Clang builds.100ifeq ($(CLANG_CROSS_FLAGS),)101CLANG_CROSS_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))102GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)gcc 2>/dev/null))103ifneq ($(GCC_TOOLCHAIN_DIR),)104CLANG_CROSS_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))105CLANG_CROSS_FLAGS += --sysroot=$(shell $(CROSS_COMPILE)gcc -print-sysroot)106CLANG_CROSS_FLAGS += --gcc-toolchain=$(realpath $(GCC_TOOLCHAIN_DIR)/..)107endif # GCC_TOOLCHAIN_DIR108endif # CLANG_CROSS_FLAGS109CFLAGS += $(CLANG_CROSS_FLAGS)110AFLAGS += $(CLANG_CROSS_FLAGS)111else112CLANG_CROSS_FLAGS :=113endif # CROSS_COMPILE114 115# Hack to avoid type-punned warnings on old systems such as RHEL5:116# We should be changing CFLAGS and checking gcc version, but this117# will do for now and keep the above -Wstrict-aliasing=3 in place118# in newer systems.119# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h120#121# See https://lore.kernel.org/lkml/9a8748490611281710g78402fbeh8ff7fcc162dbcbca@mail.gmail.com/122# and https://gcc.gnu.org/gcc-4.8/changes.html,123# that takes into account Linus's comments (search for Wshadow) for the reasoning about124# -Wshadow not being interesting before gcc 4.8.125 126ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3127EXTRA_WARNINGS += -fno-strict-aliasing128EXTRA_WARNINGS += -Wno-shadow129else130EXTRA_WARNINGS += -Wshadow131endif132 133ifneq ($(findstring $(MAKEFLAGS), w),w)134PRINT_DIR = --no-print-directory135else136NO_SUBDIR = :137endif138 139# If the user is running make -s (silent mode), suppress echoing of commands140# make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.141ifeq ($(filter 3.%,$(MAKE_VERSION)),)142short-opts := $(firstword -$(MAKEFLAGS))143else144short-opts := $(filter-out --%,$(MAKEFLAGS))145endif146 147ifneq ($(findstring s,$(short-opts)),)148 silent=1149endif150 151#152# Define a callable command for descending to a new directory153#154# Call by doing: $(call descend,directory[,target])155#156descend = \157 +mkdir -p $(OUTPUT)$(1) && \158 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)159 160QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir161QUIET_SUBDIR1 =162 163ifneq ($(silent),1)164 ifneq ($(V),1)165 QUIET_CC = @echo ' CC '$@;166 QUIET_CC_FPIC = @echo ' CC FPIC '$@;167 QUIET_CLANG = @echo ' CLANG '$@;168 QUIET_AR = @echo ' AR '$@;169 QUIET_LINK = @echo ' LINK '$@;170 QUIET_MKDIR = @echo ' MKDIR '$@;171 QUIET_GEN = @echo ' GEN '$@;172 QUIET_SUBDIR0 = +@subdir=173 QUIET_SUBDIR1 = ;$(NO_SUBDIR) \174 echo ' SUBDIR '$$subdir; \175 $(MAKE) $(PRINT_DIR) -C $$subdir176 QUIET_FLEX = @echo ' FLEX '$@;177 QUIET_BISON = @echo ' BISON '$@;178 QUIET_GENSKEL = @echo ' GENSKEL '$@;179 180 descend = \181 +@echo ' DESCEND '$(1); \182 mkdir -p $(OUTPUT)$(1) && \183 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)184 185 QUIET_CLEAN = @printf ' CLEAN %s\n' $1;186 QUIET_INSTALL = @printf ' INSTALL %s\n' $1;187 QUIET_UNINST = @printf ' UNINST %s\n' $1;188 endif189endif190 191pound := \#192