1ifneq ($(O),)
2ifeq ($(origin O), command line)
3	dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
4	ABSOLUTE_O := $(shell cd $(O) ; pwd)
5	OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)
6	COMMAND_O := O=$(ABSOLUTE_O)
7ifeq ($(objtree),)
8	objtree := $(O)
9endif
10endif
11endif
12
13# check that the output directory actually exists
14ifneq ($(OUTPUT),)
15OUTDIR := $(shell cd $(OUTPUT) && /bin/pwd)
16$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
17endif
18
19#
20# Include saner warnings here, which can catch bugs:
21#
22EXTRA_WARNINGS := -Wbad-function-cast
23EXTRA_WARNINGS += -Wdeclaration-after-statement
24EXTRA_WARNINGS += -Wformat-security
25EXTRA_WARNINGS += -Wformat-y2k
26EXTRA_WARNINGS += -Winit-self
27EXTRA_WARNINGS += -Wmissing-declarations
28EXTRA_WARNINGS += -Wmissing-prototypes
29EXTRA_WARNINGS += -Wnested-externs
30EXTRA_WARNINGS += -Wno-system-headers
31EXTRA_WARNINGS += -Wold-style-definition
32EXTRA_WARNINGS += -Wpacked
33EXTRA_WARNINGS += -Wredundant-decls
34EXTRA_WARNINGS += -Wshadow
35EXTRA_WARNINGS += -Wstrict-prototypes
36EXTRA_WARNINGS += -Wswitch-default
37EXTRA_WARNINGS += -Wswitch-enum
38EXTRA_WARNINGS += -Wundef
39EXTRA_WARNINGS += -Wwrite-strings
40EXTRA_WARNINGS += -Wformat
41
42ifneq ($(CC), clang)
43EXTRA_WARNINGS += -Wstrict-aliasing=3
44endif
45
46# Hack to avoid type-punned warnings on old systems such as RHEL5:
47# We should be changing CFLAGS and checking gcc version, but this
48# will do for now and keep the above -Wstrict-aliasing=3 in place
49# in newer systems.
50# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h
51ifneq ($(filter 3.%,$(MAKE_VERSION)),)  # make-3
52EXTRA_WARNINGS += -fno-strict-aliasing
53endif
54
55ifneq ($(findstring $(MAKEFLAGS), w),w)
56PRINT_DIR = --no-print-directory
57else
58NO_SUBDIR = :
59endif
60
61ifneq ($(filter 4.%,$(MAKE_VERSION)),)  # make-4
62ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
63  silent=1
64endif
65else					# make-3.8x
66ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
67  silent=1
68endif
69endif
70
71#
72# Define a callable command for descending to a new directory
73#
74# Call by doing: $(call descend,directory[,target])
75#
76descend = \
77	+mkdir -p $(OUTPUT)$(1) && \
78	$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
79
80QUIET_SUBDIR0  = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
81QUIET_SUBDIR1  =
82
83ifneq ($(silent),1)
84  ifneq ($(V),1)
85	QUIET_CC       = @echo '  CC       '$@;
86	QUIET_CC_FPIC  = @echo '  CC FPIC  '$@;
87	QUIET_AR       = @echo '  AR       '$@;
88	QUIET_LINK     = @echo '  LINK     '$@;
89	QUIET_MKDIR    = @echo '  MKDIR    '$@;
90	QUIET_GEN      = @echo '  GEN      '$@;
91	QUIET_SUBDIR0  = +@subdir=
92	QUIET_SUBDIR1  = ;$(NO_SUBDIR) \
93			  echo '  SUBDIR   '$$subdir; \
94			 $(MAKE) $(PRINT_DIR) -C $$subdir
95	QUIET_FLEX     = @echo '  FLEX     '$@;
96	QUIET_BISON    = @echo '  BISON    '$@;
97
98	descend = \
99		+@echo	       '  DESCEND  '$(1); \
100		mkdir -p $(OUTPUT)$(1) && \
101		$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
102
103	QUIET_CLEAN    = @printf '  CLEAN    %s\n' $1;
104	QUIET_INSTALL  = @printf '  INSTALL  %s\n' $1;
105  endif
106endif
107