1 # ==========================================================================
3 # ==========================================================================
5 BB_VER = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
9 # -std=gnu99 needed for [U]LLONG_MAX on some systems
10 CPPFLAGS += $(call cc-option,-std=gnu99,)
14 $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include -I$(srctree)/libbb) \
15 -include include/autoconf.h \
16 -D_GNU_SOURCE -DNDEBUG \
17 $(if $(CONFIG_LFS),-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64) \
18 -D"BB_VER=KBUILD_STR($(BB_VER))"
20 CFLAGS += $(call cc-option,-Wall,)
21 CFLAGS += $(call cc-option,-Wshadow,)
22 CFLAGS += $(call cc-option,-Wwrite-strings,)
23 CFLAGS += $(call cc-option,-Wundef,)
24 CFLAGS += $(call cc-option,-Wstrict-prototypes,)
25 CFLAGS += $(call cc-option,-Wunused -Wunused-parameter,)
26 CFLAGS += $(call cc-option,-Wunused-function -Wunused-value,)
27 CFLAGS += $(call cc-option,-Wmissing-prototypes -Wmissing-declarations,)
28 CFLAGS += $(call cc-option,-Wno-format-security,)
29 # warn about C99 declaration after statement
30 CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
31 # If you want to add more -Wsomething above, make sure that it is
32 # still possible to build bbox without warnings.
34 ifeq ($(CONFIG_WERROR),y)
35 CFLAGS += $(call cc-option,-Werror,)
37 ## gcc version 4.4.0 20090506 (Red Hat 4.4.0-4) (GCC) is a PITA:
38 ## const char *ptr; ... off_t v = *(off_t*)ptr; -> BOOM
39 ## and no easy way to convince it to shut the hell up.
40 ## We have a lot of such things all over the place.
41 ## Classic *(off_t*)(void*)ptr does not work,
42 ## and I am unwilling to do crazy gcc specific ({ void *ppp = ...; })
43 ## stuff in macros. This would obfuscate the code too much.
44 ## Maybe try __attribute__((__may_alias__))?
45 #CFLAGS += $(call cc-ifversion, -eq, 0404, -fno-strict-aliasing)
47 # gcc 3.x emits bogus "old style proto" warning on find.c:alloc_action()
48 CFLAGS += $(call cc-ifversion, -ge, 0400, -Wold-style-definition)
51 # "clang-9: warning: optimization flag '-finline-limit=0' is not supported
52 CFLAGS += $(call cc-option,-finline-limit=0,)
55 CFLAGS += $(call cc-option,-fno-builtin-strlen -fomit-frame-pointer -ffunction-sections -fdata-sections,)
56 # -fno-guess-branch-probability: prohibit pseudo-random guessing
57 # of branch probabilities (hopefully makes bloatcheck more stable):
58 CFLAGS += $(call cc-option,-fno-guess-branch-probability,)
59 CFLAGS += $(call cc-option,-funsigned-char,)
62 # "clang-9: warning: argument unused during compilation: '-static-libgcc'"
63 CFLAGS += $(call cc-option,-static-libgcc,)
66 CFLAGS += $(call cc-option,-falign-functions=1,)
68 # "clang-9: warning: optimization flag '-falign-jumps=1' is not supported" (and same for other two)
69 CFLAGS += $(call cc-option,-falign-jumps=1 -falign-labels=1 -falign-loops=1,)
72 # Defeat .eh_frame bloat (gcc 4.6.3 x86-32 defconfig: 20% smaller busybox binary):
73 CFLAGS += $(call cc-option,-fno-unwind-tables,)
74 CFLAGS += $(call cc-option,-fno-asynchronous-unwind-tables,)
75 # No automatic printf->puts,putchar conversions
76 # (try disabling this and comparing assembly, it's instructive)
77 CFLAGS += $(call cc-option,-fno-builtin-printf,)
79 # clang-9 does not like "str" + N and "if (CONFIG_ITEM && cond)" constructs
80 CFLAGS += $(call cc-option,-Wno-string-plus-int -Wno-constant-logical-operand)
82 # FIXME: These warnings are at least partially to be concerned about and should
84 #CFLAGS += $(call cc-option,-Wconversion,)
86 ifneq ($(CONFIG_DEBUG),y)
87 CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
89 CFLAGS += $(call cc-option,-g,)
90 #CFLAGS += "-D_FORTIFY_SOURCE=2"
91 ifeq ($(CONFIG_DEBUG_PESSIMIZE),y)
92 CFLAGS += $(call cc-option,-O0,)
94 CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
97 ifeq ($(CONFIG_DEBUG_SANITIZE),y)
98 CFLAGS += $(call cc-option,-fsanitize=address,)
99 CFLAGS += $(call cc-option,-fsanitize=leak,)
100 CFLAGS += $(call cc-option,-fsanitize=undefined,)
103 # If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)...
108 # Usage: $(eval $(call pkg_check_modules,VARIABLE-PREFIX,MODULES))
109 define pkg_check_modules
110 $(1)_CFLAGS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --cflags $(2))
111 $(1)_LIBS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --libs $(2))
114 ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
115 # on i386: 14% smaller libbusybox.so
116 # (code itself is 9% bigger, we save on relocs/PLT/GOT)
117 CFLAGS += $(ARCH_FPIC)
118 # and another 4% reduction of libbusybox.so:
119 # (external entry points must be marked EXTERNALLY_VISIBLE)
120 CFLAGS += $(call cc-option,-fvisibility=hidden)
123 ifeq ($(CONFIG_STATIC),y)
124 CFLAGS_busybox += -static
125 PKG_CONFIG_FLAGS += --static
128 ifeq ($(CONFIG_PIE),y)
129 CFLAGS_busybox += $(ARCH_PIE)
130 CFLAGS += $(ARCH_FPIE)
133 ifneq ($(CONFIG_EXTRA_CFLAGS),)
134 CFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_CFLAGS)))
138 # Note: both "" (string consisting of two quote chars) and empty string
139 # are possible, and should be skipped below.
140 ifneq ($(subst "",,$(CONFIG_SYSROOT)),)
141 CFLAGS += --sysroot=$(CONFIG_SYSROOT)
142 export SYSROOT=$(CONFIG_SYSROOT)
145 # Android has no separate crypt library
146 # gcc-4.2.1 fails if we try to feed C source on stdin:
147 # echo 'int main(void){return 0;}' | $(CC) $(CFLAGS) -lcrypt -o /dev/null -xc -
148 # fall back to using a temp file:
149 CRYPT_AVAILABLE := $(shell echo 'int main(void){return 0;}' >crypttest.c; $(CC) $(CFLAGS) -lcrypt -o /dev/null crypttest.c >/dev/null 2>&1 && echo "y"; rm crypttest.c)
150 ifeq ($(CRYPT_AVAILABLE),y)
155 # libm may be needed for dc, awk, ntpd
156 # librt may be needed for clock_gettime()
158 # libpam may use libpthread, libdl and/or libaudit.
159 # On some platforms that requires an explicit -lpthread, -ldl, -laudit.
160 # However, on *other platforms* it fails when some of those flags
161 # given needlessly. On some systems, crypt needs pthread.
163 # I even had a system where a runtime test for pthread
164 # (similar to CRYPT_AVAILABLE test above) was not reliable.
166 # Do not propagate this mess by adding libraries to CONFIG_PAM/CRYPT_AVAILABLE blocks.
167 # Add libraries you need to CONFIG_EXTRA_LDLIBS instead.
169 ifeq ($(CONFIG_PAM),y)
170 LDLIBS += pam pam_misc
173 ifeq ($(CONFIG_SELINUX),y)
174 SELINUX_PC_MODULES = libselinux libsepol
175 $(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
176 CPPFLAGS += $(SELINUX_CFLAGS)
177 LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
180 ifeq ($(CONFIG_FEATURE_NSLOOKUP_BIG),y)
184 ifeq ($(CONFIG_EFENCE),y)
188 ifeq ($(CONFIG_DMALLOC),y)
192 # If a flat binary should be built, CFLAGS_busybox="-elf2flt"
193 # env var should be set for make invocation.
194 # Here we check whether CFLAGS_busybox indeed contains that flag.
195 # (For historical reasons, we also check LDFLAGS, which doesn't
196 # seem to be entirely correct variable to put "-elf2flt" into).
198 ifneq (,$(findstring $(W_ELF2FLT),$(LDFLAGS) $(CFLAGS_busybox)))
202 ifneq ($(CONFIG_EXTRA_LDFLAGS),)
203 LDFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_LDFLAGS)))
207 ifneq ($(CONFIG_EXTRA_LDLIBS),)
208 LDLIBS += $(strip $(subst ",,$(CONFIG_EXTRA_LDLIBS)))
212 # Busybox is a stack-fatty so make sure we increase default size
213 # TODO: use "make stksizes" to find & fix big stack users
214 # (we stole scripts/checkstack.pl from the kernel... thanks guys!)
215 # Reduced from 20k to 16k in 1.9.0.