1# SPDX-License-Identifier: GPL-2.0
2ifneq ($(O),)
3ifeq ($(origin O), command line)
4	dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
5	ABSOLUTE_O := $(shell 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 += -Wshadow
36EXTRA_WARNINGS += -Wstrict-prototypes
37EXTRA_WARNINGS += -Wswitch-default
38EXTRA_WARNINGS += -Wswitch-enum
39EXTRA_WARNINGS += -Wundef
40EXTRA_WARNINGS += -Wwrite-strings
41EXTRA_WARNINGS += -Wformat
42
43CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
44
45# Makefiles suck: This macro sets a default value of $(2) for the
46# variable named by $(1), unless the variable has been set by
47# environment or command line. This is necessary for CC and AR
48# because make sets default values, so the simpler ?= approach
49# won't work as expected.
50define allow-override
51  $(if $(or $(findstring environment,$(origin $(1))),\
52            $(findstring command line,$(origin $(1)))),,\
53    $(eval $(1) = $(2)))
54endef
55
56# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
57$(call allow-override,CC,$(CROSS_COMPILE)gcc)
58$(call allow-override,AR,$(CROSS_COMPILE)ar)
59$(call allow-override,LD,$(CROSS_COMPILE)ld)
60$(call allow-override,CXX,$(CROSS_COMPILE)g++)
61$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
62
63ifeq ($(CC_NO_CLANG), 1)
64EXTRA_WARNINGS += -Wstrict-aliasing=3
65endif
66
67# Hack to avoid type-punned warnings on old systems such as RHEL5:
68# We should be changing CFLAGS and checking gcc version, but this
69# will do for now and keep the above -Wstrict-aliasing=3 in place
70# in newer systems.
71# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h
72ifneq ($(filter 3.%,$(MAKE_VERSION)),)  # make-3
73EXTRA_WARNINGS += -fno-strict-aliasing
74endif
75
76ifneq ($(findstring $(MAKEFLAGS), w),w)
77PRINT_DIR = --no-print-directory
78else
79NO_SUBDIR = :
80endif
81
82ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
83  silent=1
84endif
85
86#
87# Define a callable command for descending to a new directory
88#
89# Call by doing: $(call descend,directory[,target])
90#
91descend = \
92	+mkdir -p $(OUTPUT)$(1) && \
93	$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
94
95QUIET_SUBDIR0  = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
96QUIET_SUBDIR1  =
97
98ifneq ($(silent),1)
99  ifneq ($(V),1)
100	QUIET_CC       = @echo '  CC       '$@;
101	QUIET_CC_FPIC  = @echo '  CC FPIC  '$@;
102	QUIET_AR       = @echo '  AR       '$@;
103	QUIET_LINK     = @echo '  LINK     '$@;
104	QUIET_MKDIR    = @echo '  MKDIR    '$@;
105	QUIET_GEN      = @echo '  GEN      '$@;
106	QUIET_SUBDIR0  = +@subdir=
107	QUIET_SUBDIR1  = ;$(NO_SUBDIR) \
108			  echo '  SUBDIR   '$$subdir; \
109			 $(MAKE) $(PRINT_DIR) -C $$subdir
110	QUIET_FLEX     = @echo '  FLEX     '$@;
111	QUIET_BISON    = @echo '  BISON    '$@;
112
113	descend = \
114		+@echo	       '  DESCEND  '$(1); \
115		mkdir -p $(OUTPUT)$(1) && \
116		$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
117
118	QUIET_CLEAN    = @printf '  CLEAN    %s\n' $1;
119	QUIET_INSTALL  = @printf '  INSTALL  %s\n' $1;
120	QUIET_UNINST   = @printf '  UNINST   %s\n' $1;
121  endif
122endif
123