1# ========================================================================== 2# Build system 3# ========================================================================== 4 5BB_VER = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION) 6export BB_VER 7SKIP_STRIP = n 8 9# -std=gnu99 needed for [U]LLONG_MAX on some systems 10CPPFLAGS += $(call cc-option,-std=gnu99,) 11 12CPPFLAGS += \ 13 -Iinclude -Ilibbb \ 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))" -DBB_BT=AUTOCONF_TIMESTAMP 19 20CFLAGS += $(call cc-option,-Wall,) 21CFLAGS += $(call cc-option,-Wshadow,) 22CFLAGS += $(call cc-option,-Wwrite-strings,) 23CFLAGS += $(call cc-option,-Wundef,) 24CFLAGS += $(call cc-option,-Wstrict-prototypes,) 25CFLAGS += $(call cc-option,-Wunused -Wunused-parameter,) 26CFLAGS += $(call cc-option,-Wmissing-prototypes -Wmissing-declarations,) 27# warn about C99 declaration after statement 28CFLAGS += $(call cc-option,-Wdeclaration-after-statement,) 29# If you want to add more -Wsomething above, make sure that it is 30# still possible to build bbox without warnings. 31 32ifeq ($(CONFIG_WERROR),y) 33CFLAGS += $(call cc-option,-Werror,) 34endif 35# gcc 3.x emits bogus "old style proto" warning on find.c:alloc_action() 36CFLAGS += $(call cc-ifversion, -ge, 0400, -Wold-style-definition) 37 38CFLAGS += $(call cc-option,-fno-builtin-strlen -finline-limit=0 -fomit-frame-pointer -ffunction-sections -fdata-sections,) 39# -fno-guess-branch-probability: prohibit pseudo-random guessing 40# of branch probabilities (hopefully makes bloatcheck more stable): 41CFLAGS += $(call cc-option,-fno-guess-branch-probability,) 42CFLAGS += $(call cc-option,-funsigned-char -static-libgcc,) 43CFLAGS += $(call cc-option,-falign-functions=1 -falign-jumps=1 -falign-labels=1 -falign-loops=1,) 44 45# FIXME: These warnings are at least partially to be concerned about and should 46# be fixed.. 47#CFLAGS += $(call cc-option,-Wconversion,) 48 49ifneq ($(CONFIG_DEBUG),y) 50CFLAGS += $(call cc-option,-Os,) 51else 52CFLAGS += $(call cc-option,-g,) 53#CFLAGS += "-D_FORTIFY_SOURCE=2" 54ifeq ($(CONFIG_DEBUG_PESSIMIZE),y) 55CFLAGS += $(call cc-option,-O0,) 56else 57CFLAGS += $(call cc-option,-Os,) 58endif 59endif 60 61# If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)... 62ARCH_FPIC ?= -fpic 63ARCH_FPIE ?= -fpie 64ARCH_PIE ?= -pie 65 66ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y) 67# on i386: 14% smaller libbusybox.so 68# (code itself is 9% bigger, we save on relocs/PLT/GOT) 69CFLAGS += $(ARCH_FPIC) 70# and another 4% reduction of libbusybox.so: 71# (external entry points must be marked EXTERNALLY_VISIBLE) 72CFLAGS += $(call cc-option,-fvisibility=hidden) 73endif 74 75ifeq ($(CONFIG_STATIC),y) 76CFLAGS_busybox += -static 77endif 78 79ifeq ($(CONFIG_PIE),y) 80CFLAGS_busybox += $(ARCH_PIE) 81CFLAGS += $(ARCH_FPIE) 82endif 83 84LDLIBS += m crypt 85 86ifeq ($(CONFIG_PAM),y) 87LDLIBS += pam pam_misc 88endif 89 90ifeq ($(CONFIG_SELINUX),y) 91LDLIBS += selinux sepol 92endif 93 94ifeq ($(CONFIG_EFENCE),y) 95LDLIBS += efence 96endif 97 98ifeq ($(CONFIG_DMALLOC),y) 99LDLIBS += dmalloc 100endif 101 102# If a flat binary should be built, CFLAGS_busybox="-Wl,-elf2flt" 103# env var should be set for make invocation. 104# Here we check whether CFLAGS_busybox indeed contains that flag. 105# (For historical reasons, we also check LDFLAGS, which doesn't 106# seem to be entirely correct variable to put "-Wl,-elf2flt" into). 107W_ELF2FLT = -Wl,-elf2flt 108ifneq (,$(findstring $(W_ELF2FLT),$(LDFLAGS) $(CFLAGS_busybox))) 109SKIP_STRIP = y 110endif 111 112# Busybox is a stack-fatty so make sure we increase default size 113# TODO: use "make stksizes" to find & fix big stack users 114# (we stole scripts/checkstack.pl from the kernel... thanks guys!) 115# Reduced from 20k to 16k in 1.9.0. 116FLTFLAGS += -s 16000 117