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- # SPDX-License-Identifier: GPL-2.0
- ifneq ($(O),)
- ifeq ($(origin O), command line)
- $(if $(shell cd $(PWD); test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
- ABSOLUTE_O := $(shell cd $(PWD); cd $(O) ; pwd)
- OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)
- COMMAND_O := O=$(ABSOLUTE_O)
- ifeq ($(objtree),)
- objtree := $(O)
- endif
- endif
- endif
- # check that the output directory actually exists
- ifneq ($(OUTPUT),)
- OUTDIR := $(shell cd $(OUTPUT) && pwd)
- $(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
- endif
- #
- # Include saner warnings here, which can catch bugs:
- #
- EXTRA_WARNINGS := -Wbad-function-cast
- EXTRA_WARNINGS += -Wdeclaration-after-statement
- EXTRA_WARNINGS += -Wformat-security
- EXTRA_WARNINGS += -Wformat-y2k
- EXTRA_WARNINGS += -Winit-self
- EXTRA_WARNINGS += -Wmissing-declarations
- EXTRA_WARNINGS += -Wmissing-prototypes
- EXTRA_WARNINGS += -Wnested-externs
- EXTRA_WARNINGS += -Wno-system-headers
- EXTRA_WARNINGS += -Wold-style-definition
- EXTRA_WARNINGS += -Wpacked
- EXTRA_WARNINGS += -Wredundant-decls
- EXTRA_WARNINGS += -Wstrict-prototypes
- EXTRA_WARNINGS += -Wswitch-default
- EXTRA_WARNINGS += -Wswitch-enum
- EXTRA_WARNINGS += -Wundef
- EXTRA_WARNINGS += -Wwrite-strings
- EXTRA_WARNINGS += -Wformat
- EXTRA_WARNINGS += -Wno-type-limits
- # Makefiles suck: This macro sets a default value of $(2) for the
- # variable named by $(1), unless the variable has been set by
- # environment or command line. This is necessary for CC and AR
- # because make sets default values, so the simpler ?= approach
- # won't work as expected.
- define allow-override
- $(if $(or $(findstring environment,$(origin $(1))),\
- $(findstring command line,$(origin $(1)))),,\
- $(eval $(1) = $(2)))
- endef
- ifneq ($(LLVM),)
- ifneq ($(filter %/,$(LLVM)),)
- LLVM_PREFIX := $(LLVM)
- else ifneq ($(filter -%,$(LLVM)),)
- LLVM_SUFFIX := $(LLVM)
- endif
- $(call allow-override,CC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))
- $(call allow-override,AR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX))
- $(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX))
- $(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX))
- $(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX))
- else
- # Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
- $(call allow-override,CC,$(CROSS_COMPILE)gcc)
- $(call allow-override,AR,$(CROSS_COMPILE)ar)
- $(call allow-override,LD,$(CROSS_COMPILE)ld)
- $(call allow-override,CXX,$(CROSS_COMPILE)g++)
- $(call allow-override,STRIP,$(CROSS_COMPILE)strip)
- endif
- CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
- ifneq ($(LLVM),)
- HOSTAR ?= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
- HOSTCC ?= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
- HOSTLD ?= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
- else
- HOSTAR ?= ar
- HOSTCC ?= gcc
- HOSTLD ?= ld
- endif
- # Some tools require Clang, LLC and/or LLVM utils
- CLANG ?= clang
- LLC ?= llc
- LLVM_CONFIG ?= llvm-config
- LLVM_OBJCOPY ?= llvm-objcopy
- LLVM_STRIP ?= llvm-strip
- # Some tools require bpftool
- SYSTEM_BPFTOOL ?= bpftool
- RUSTC ?= rustc
- ifeq ($(CC_NO_CLANG), 1)
- EXTRA_WARNINGS += -Wstrict-aliasing=3
- else ifneq ($(CROSS_COMPILE),)
- # Allow userspace to override CLANG_CROSS_FLAGS to specify their own
- # sysroots and flags or to avoid the GCC call in pure Clang builds.
- ifeq ($(CLANG_CROSS_FLAGS),)
- CLANG_TARGET := $(notdir $(CROSS_COMPILE:%-=%))
- CLANG_TARGET := $(subst s390-linux,s390x-linux,$(CLANG_TARGET))
- CLANG_CROSS_FLAGS := --target=$(CLANG_TARGET)
- GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)gcc 2>/dev/null))
- ifneq ($(GCC_TOOLCHAIN_DIR),)
- CLANG_CROSS_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
- CLANG_CROSS_FLAGS += --sysroot=$(shell $(CROSS_COMPILE)gcc -print-sysroot)
- CLANG_CROSS_FLAGS += --gcc-toolchain=$(realpath $(GCC_TOOLCHAIN_DIR)/..)
- endif # GCC_TOOLCHAIN_DIR
- endif # CLANG_CROSS_FLAGS
- CFLAGS += $(CLANG_CROSS_FLAGS)
- AFLAGS += $(CLANG_CROSS_FLAGS)
- else
- CLANG_CROSS_FLAGS :=
- endif # CROSS_COMPILE
- # Hack to avoid type-punned warnings on old systems such as RHEL5:
- # We should be changing CFLAGS and checking gcc version, but this
- # will do for now and keep the above -Wstrict-aliasing=3 in place
- # in newer systems.
- # Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h
- #
- # See https://lore.kernel.org/lkml/9a8748490611281710g78402fbeh8ff7fcc162dbcbca@mail.gmail.com/
- # and https://gcc.gnu.org/gcc-4.8/changes.html,
- # that takes into account Linus's comments (search for Wshadow) for the reasoning about
- # -Wshadow not being interesting before gcc 4.8.
- ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3
- EXTRA_WARNINGS += -fno-strict-aliasing
- EXTRA_WARNINGS += -Wno-shadow
- else
- EXTRA_WARNINGS += -Wshadow
- endif
- ifneq ($(findstring $(MAKEFLAGS), w),w)
- PRINT_DIR = --no-print-directory
- else
- NO_SUBDIR = :
- endif
- # Beautify output
- # ---------------------------------------------------------------------------
- #
- # Most of build commands in Kbuild start with "cmd_". You can optionally define
- # "quiet_cmd_*". If defined, the short log is printed. Otherwise, no log from
- # that command is printed by default.
- #
- # e.g.)
- # quiet_cmd_depmod = DEPMOD $(MODLIB)
- # cmd_depmod = $(srctree)/scripts/depmod.sh $(DEPMOD) $(KERNELRELEASE)
- #
- # A simple variant is to prefix commands with $(Q) - that's useful
- # for commands that shall be hidden in non-verbose mode.
- #
- # $(Q)$(MAKE) $(build)=scripts/basic
- #
- # To put more focus on warnings, be less verbose as default
- # Use 'make V=1' to see the full commands
- ifeq ($(V),1)
- quiet =
- Q =
- else
- quiet = quiet_
- Q = @
- endif
- # If the user is running make -s (silent mode), suppress echoing of commands
- # make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.
- ifeq ($(filter 3.%,$(MAKE_VERSION)),)
- short-opts := $(firstword -$(MAKEFLAGS))
- else
- short-opts := $(filter-out --%,$(MAKEFLAGS))
- endif
- ifneq ($(findstring s,$(short-opts)),)
- silent=1
- quiet=silent_
- endif
- export quiet Q
- #
- # Define a callable command for descending to a new directory
- #
- # Call by doing: $(call descend,directory[,target])
- #
- descend = \
- +mkdir -p $(OUTPUT)$(1) && \
- $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
- QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
- QUIET_SUBDIR1 =
- ifneq ($(silent),1)
- ifneq ($(V),1)
- QUIET_CC = @echo ' CC '$@;
- QUIET_CC_FPIC = @echo ' CC FPIC '$@;
- QUIET_CLANG = @echo ' CLANG '$@;
- QUIET_AR = @echo ' AR '$@;
- QUIET_LINK = @echo ' LINK '$@;
- QUIET_MKDIR = @echo ' MKDIR '$@;
- QUIET_GEN = @echo ' GEN '$@;
- QUIET_SUBDIR0 = +@subdir=
- QUIET_SUBDIR1 = ;$(NO_SUBDIR) \
- echo ' SUBDIR '$$subdir; \
- $(MAKE) $(PRINT_DIR) -C $$subdir
- QUIET_FLEX = @echo ' FLEX '$@;
- QUIET_BISON = @echo ' BISON '$@;
- QUIET_GENSKEL = @echo ' GENSKEL '$@;
- descend = \
- +@echo ' DESCEND '$(1); \
- mkdir -p $(OUTPUT)$(1) && \
- $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
- QUIET_CLEAN = @printf ' CLEAN %s\n' $1;
- QUIET_INSTALL = @printf ' INSTALL %s\n' $1;
- QUIET_UNINST = @printf ' UNINST %s\n' $1;
- endif
- endif
- pound := \#
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