1 # SPDX-License-Identifier: GPL-2.0 2 ifneq ($(O),) 3 ifeq ($(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=$(ABSOLUTE_O) 8 ifeq ($(objtree),) 9 objtree := $(O) 10 endif 11 endif 12 endif 13 14 # check that the output directory actually exists 15 ifneq ($(OUTPUT),) 16 OUTDIR := $(shell cd $(OUTPUT) && pwd) 17 $(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist)) 18 endif 19 20 # 21 # Include saner warnings here, which can catch bugs: 22 # 23 EXTRA_WARNINGS := -Wbad-function-cast 24 EXTRA_WARNINGS += -Wdeclaration-after-statement 25 EXTRA_WARNINGS += -Wformat-security 26 EXTRA_WARNINGS += -Wformat-y2k 27 EXTRA_WARNINGS += -Winit-self 28 EXTRA_WARNINGS += -Wmissing-declarations 29 EXTRA_WARNINGS += -Wmissing-prototypes 30 EXTRA_WARNINGS += -Wnested-externs 31 EXTRA_WARNINGS += -Wno-system-headers 32 EXTRA_WARNINGS += -Wold-style-definition 33 EXTRA_WARNINGS += -Wpacked 34 EXTRA_WARNINGS += -Wredundant-decls 35 EXTRA_WARNINGS += -Wstrict-prototypes 36 EXTRA_WARNINGS += -Wswitch-default 37 EXTRA_WARNINGS += -Wswitch-enum 38 EXTRA_WARNINGS += -Wundef 39 EXTRA_WARNINGS += -Wwrite-strings 40 EXTRA_WARNINGS += -Wformat 41 EXTRA_WARNINGS += -Wno-type-limits 42 43 # Makefiles suck: This macro sets a default value of $(2) for the 44 # variable named by $(1), unless the variable has been set by 45 # environment or command line. This is necessary for CC and AR 46 # because make sets default values, so the simpler ?= approach 47 # won't work as expected. 48 define allow-override 49 $(if $(or $(findstring environment,$(origin $(1))),\ 50 $(findstring command line,$(origin $(1)))),,\ 51 $(eval $(1) = $(2))) 52 endef 53 54 ifneq ($(LLVM),) 55 ifneq ($(filter %/,$(LLVM)),) 56 LLVM_PREFIX := $(LLVM) 57 else ifneq ($(filter -%,$(LLVM)),) 58 LLVM_SUFFIX := $(LLVM) 59 endif 60 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)) 66 else 67 # 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) 73 endif 74 75 CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?) 76 77 ifneq ($(LLVM),) 78 HOSTAR ?= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX) 79 HOSTCC ?= $(LLVM_PREFIX)clang$(LLVM_SUFFIX) 80 HOSTLD ?= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX) 81 else 82 HOSTAR ?= ar 83 HOSTCC ?= gcc 84 HOSTLD ?= ld 85 endif 86 87 # Some tools require Clang, LLC and/or LLVM utils 88 CLANG ?= clang 89 LLC ?= llc 90 LLVM_CONFIG ?= llvm-config 91 LLVM_OBJCOPY ?= llvm-objcopy 92 LLVM_STRIP ?= llvm-strip 93 94 ifeq ($(CC_NO_CLANG), 1) 95 EXTRA_WARNINGS += -Wstrict-aliasing=3 96 97 else ifneq ($(CROSS_COMPILE),) 98 # Allow userspace to override CLANG_CROSS_FLAGS to specify their own 99 # sysroots and flags or to avoid the GCC call in pure Clang builds. 100 ifeq ($(CLANG_CROSS_FLAGS),) 101 CLANG_CROSS_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%)) 102 GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)gcc 2>/dev/null)) 103 ifneq ($(GCC_TOOLCHAIN_DIR),) 104 CLANG_CROSS_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) 105 CLANG_CROSS_FLAGS += --sysroot=$(shell $(CROSS_COMPILE)gcc -print-sysroot) 106 CLANG_CROSS_FLAGS += --gcc-toolchain=$(realpath $(GCC_TOOLCHAIN_DIR)/..) 107 endif # GCC_TOOLCHAIN_DIR 108 endif # CLANG_CROSS_FLAGS 109 CFLAGS += $(CLANG_CROSS_FLAGS) 110 AFLAGS += $(CLANG_CROSS_FLAGS) 111 else 112 CLANG_CROSS_FLAGS := 113 endif # CROSS_COMPILE 114 115 # Hack to avoid type-punned warnings on old systems such as RHEL5: 116 # We should be changing CFLAGS and checking gcc version, but this 117 # will do for now and keep the above -Wstrict-aliasing=3 in place 118 # in newer systems. 119 # Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h 120 # 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 about 124 # -Wshadow not being interesting before gcc 4.8. 125 126 ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3 127 EXTRA_WARNINGS += -fno-strict-aliasing 128 EXTRA_WARNINGS += -Wno-shadow 129 else 130 EXTRA_WARNINGS += -Wshadow 131 endif 132 133 ifneq ($(findstring $(MAKEFLAGS), w),w) 134 PRINT_DIR = --no-print-directory 135 else 136 NO_SUBDIR = : 137 endif 138 139 # If the user is running make -s (silent mode), suppress echoing of commands 140 # make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS. 141 ifeq ($(filter 3.%,$(MAKE_VERSION)),) 142 short-opts := $(firstword -$(MAKEFLAGS)) 143 else 144 short-opts := $(filter-out --%,$(MAKEFLAGS)) 145 endif 146 147 ifneq ($(findstring s,$(short-opts)),) 148 silent=1 149 endif 150 151 # 152 # Define a callable command for descending to a new directory 153 # 154 # Call by doing: $(call descend,directory[,target]) 155 # 156 descend = \ 157 +mkdir -p $(OUTPUT)$(1) && \ 158 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) 159 160 QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir 161 QUIET_SUBDIR1 = 162 163 ifneq ($(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 $$subdir 176 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 endif 189 endif 190 191 pound := \#
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