Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0
2ifneq ($(O),)
3ifeq ($(origin O), command line)
4 dummy := $(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 := $(O)
10endif
11endif
12endif
13
14# check that the output directory actually exists
15ifneq ($(OUTPUT),)
16OUTDIR := $(shell cd $(OUTPUT) && pwd)
17$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
18endif
19
20#
21# Include saner warnings here, which can catch bugs:
22#
23EXTRA_WARNINGS := -Wbad-function-cast
24EXTRA_WARNINGS += -Wdeclaration-after-statement
25EXTRA_WARNINGS += -Wformat-security
26EXTRA_WARNINGS += -Wformat-y2k
27EXTRA_WARNINGS += -Winit-self
28EXTRA_WARNINGS += -Wmissing-declarations
29EXTRA_WARNINGS += -Wmissing-prototypes
30EXTRA_WARNINGS += -Wnested-externs
31EXTRA_WARNINGS += -Wno-system-headers
32EXTRA_WARNINGS += -Wold-style-definition
33EXTRA_WARNINGS += -Wpacked
34EXTRA_WARNINGS += -Wredundant-decls
35EXTRA_WARNINGS += -Wstrict-prototypes
36EXTRA_WARNINGS += -Wswitch-default
37EXTRA_WARNINGS += -Wswitch-enum
38EXTRA_WARNINGS += -Wundef
39EXTRA_WARNINGS += -Wwrite-strings
40EXTRA_WARNINGS += -Wformat
41
42CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
43
44# Makefiles suck: This macro sets a default value of $(2) for the
45# variable named by $(1), unless the variable has been set by
46# environment or command line. This is necessary for CC and AR
47# because make sets default values, so the simpler ?= approach
48# won't work as expected.
49define allow-override
50 $(if $(or $(findstring environment,$(origin $(1))),\
51 $(findstring command line,$(origin $(1)))),,\
52 $(eval $(1) = $(2)))
53endef
54
55# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
56$(call allow-override,CC,$(CROSS_COMPILE)gcc)
57$(call allow-override,AR,$(CROSS_COMPILE)ar)
58$(call allow-override,LD,$(CROSS_COMPILE)ld)
59$(call allow-override,CXX,$(CROSS_COMPILE)g++)
60$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
61
62ifneq ($(LLVM),)
63HOSTAR ?= llvm-ar
64HOSTCC ?= clang
65HOSTLD ?= ld.lld
66else
67HOSTAR ?= ar
68HOSTCC ?= gcc
69HOSTLD ?= ld
70endif
71
72# Some tools require Clang, LLC and/or LLVM utils
73CLANG ?= clang
74LLC ?= llc
75LLVM_CONFIG ?= llvm-config
76LLVM_OBJCOPY ?= llvm-objcopy
77LLVM_STRIP ?= llvm-strip
78
79ifeq ($(CC_NO_CLANG), 1)
80EXTRA_WARNINGS += -Wstrict-aliasing=3
81endif
82
83# Hack to avoid type-punned warnings on old systems such as RHEL5:
84# We should be changing CFLAGS and checking gcc version, but this
85# will do for now and keep the above -Wstrict-aliasing=3 in place
86# in newer systems.
87# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h
88#
89# See https://lkml.org/lkml/2006/11/28/253 and https://gcc.gnu.org/gcc-4.8/changes.html,
90# that takes into account Linus's comments (search for Wshadow) for the reasoning about
91# -Wshadow not being interesting before gcc 4.8.
92
93ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3
94EXTRA_WARNINGS += -fno-strict-aliasing
95EXTRA_WARNINGS += -Wno-shadow
96else
97EXTRA_WARNINGS += -Wshadow
98endif
99
100ifneq ($(findstring $(MAKEFLAGS), w),w)
101PRINT_DIR = --no-print-directory
102else
103NO_SUBDIR = :
104endif
105
106ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
107 silent=1
108endif
109
110#
111# Define a callable command for descending to a new directory
112#
113# Call by doing: $(call descend,directory[,target])
114#
115descend = \
116 +mkdir -p $(OUTPUT)$(1) && \
117 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
118
119QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
120QUIET_SUBDIR1 =
121
122ifneq ($(silent),1)
123 ifneq ($(V),1)
124 QUIET_CC = @echo ' CC '$@;
125 QUIET_CC_FPIC = @echo ' CC FPIC '$@;
126 QUIET_CLANG = @echo ' CLANG '$@;
127 QUIET_AR = @echo ' AR '$@;
128 QUIET_LINK = @echo ' LINK '$@;
129 QUIET_MKDIR = @echo ' MKDIR '$@;
130 QUIET_GEN = @echo ' GEN '$@;
131 QUIET_SUBDIR0 = +@subdir=
132 QUIET_SUBDIR1 = ;$(NO_SUBDIR) \
133 echo ' SUBDIR '$$subdir; \
134 $(MAKE) $(PRINT_DIR) -C $$subdir
135 QUIET_FLEX = @echo ' FLEX '$@;
136 QUIET_BISON = @echo ' BISON '$@;
137 QUIET_GENSKEL = @echo ' GEN-SKEL '$@;
138
139 descend = \
140 +@echo ' DESCEND '$(1); \
141 mkdir -p $(OUTPUT)$(1) && \
142 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
143
144 QUIET_CLEAN = @printf ' CLEAN %s\n' $1;
145 QUIET_INSTALL = @printf ' INSTALL %s\n' $1;
146 QUIET_UNINST = @printf ' UNINST %s\n' $1;
147 endif
148endif
149
150pound := \#