LXR busybox/Makefile.flags

   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,-Wunused-function -Wunused-value,)
  27CFLAGS += $(call cc-option,-Wmissing-prototypes -Wmissing-declarations,)
  28CFLAGS += $(call cc-option,-Wno-format-security,)
  29# warn about C99 declaration after statement
  30CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
  31# If you want to add more -Wsomething above, make sure that it is
  32# still possible to build bbox without warnings.
  33
  34ifeq ($(CONFIG_WERROR),y)
  35CFLAGS += $(call cc-option,-Werror,)
  36## TODO:
  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)
  46endif
  47# gcc 3.x emits bogus "old style proto" warning on find.c:alloc_action()
  48CFLAGS += $(call cc-ifversion, -ge, 0400, -Wold-style-definition)
  49
  50CFLAGS += $(call cc-option,-fno-builtin-strlen -finline-limit=0 -fomit-frame-pointer -ffunction-sections -fdata-sections,)
  51# -fno-guess-branch-probability: prohibit pseudo-random guessing
  52# of branch probabilities (hopefully makes bloatcheck more stable):
  53CFLAGS += $(call cc-option,-fno-guess-branch-probability,)
  54CFLAGS += $(call cc-option,-funsigned-char -static-libgcc,)
  55CFLAGS += $(call cc-option,-falign-functions=1 -falign-jumps=1 -falign-labels=1 -falign-loops=1,)
  56# Defeat .eh_frame bloat (gcc 4.6.3 x86-32 defconfig: 20% smaller busybox binary):
  57CFLAGS += $(call cc-option,-fno-unwind-tables,)
  58CFLAGS += $(call cc-option,-fno-asynchronous-unwind-tables,)
  59
  60# FIXME: These warnings are at least partially to be concerned about and should
  61# be fixed..
  62#CFLAGS += $(call cc-option,-Wconversion,)
  63
  64ifneq ($(CONFIG_DEBUG),y)
  65CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  66else
  67CFLAGS += $(call cc-option,-g,)
  68#CFLAGS += "-D_FORTIFY_SOURCE=2"
  69ifeq ($(CONFIG_DEBUG_PESSIMIZE),y)
  70CFLAGS += $(call cc-option,-O0,)
  71else
  72CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  73endif
  74endif
  75
  76# If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)...
  77ARCH_FPIC ?= -fpic
  78ARCH_FPIE ?= -fpie
  79ARCH_PIE ?= -pie
  80
  81# Usage: $(eval $(call pkg_check_modules,VARIABLE-PREFIX,MODULES))
  82define pkg_check_modules
  83$(1)_CFLAGS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --cflags $(2))
  84$(1)_LIBS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --libs $(2))
  85endef
  86
  87ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
  88# on i386: 14% smaller libbusybox.so
  89# (code itself is 9% bigger, we save on relocs/PLT/GOT)
  90CFLAGS += $(ARCH_FPIC)
  91# and another 4% reduction of libbusybox.so:
  92# (external entry points must be marked EXTERNALLY_VISIBLE)
  93CFLAGS += $(call cc-option,-fvisibility=hidden)
  94endif
  95
  96ifeq ($(CONFIG_STATIC),y)
  97CFLAGS_busybox += -static
  98PKG_CONFIG_FLAGS += --static
  99endif
 100
 101ifeq ($(CONFIG_PIE),y)
 102CFLAGS_busybox += $(ARCH_PIE)
 103CFLAGS += $(ARCH_FPIE)
 104endif
 105
 106ifneq ($(CONFIG_EXTRA_CFLAGS),)
 107CFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_CFLAGS)))
 108#"))
 109endif
 110
 111# Note: both "" (string consisting of two quote chars) and empty string
 112# are possible, and should be skipped below.
 113ifneq ($(subst "",,$(CONFIG_SYSROOT)),)
 114CFLAGS += --sysroot=$(CONFIG_SYSROOT)
 115export SYSROOT=$(CONFIG_SYSROOT)
 116endif
 117
 118# Android has no separate crypt library
 119# gcc-4.2.1 fails if we try to feed C source on stdin:
 120#  echo 'int main(void){return 0;}' | $(CC) $(CFLAGS) -lcrypt -o /dev/null -xc -
 121# fall back to using a temp file:
 122CRYPT_AVAILABLE := $(shell echo 'int main(void){return 0;}' >crypttest.c; $(CC) $(CFLAGS) -lcrypt -o /dev/null crypttest.c >/dev/null 2>&1 && echo "y"; rm crypttest.c)
 123ifeq ($(CRYPT_AVAILABLE),y)
 124LDLIBS += m crypt
 125else
 126LDLIBS += m
 127endif
 128
 129ifeq ($(CONFIG_PAM),y)
 130# libpam uses libpthread, so for static builds busybox must be linked to
 131# libpthread. On some platforms that requires an explicit -lpthread, so
 132# it should be in LDLIBS. For non-static builds, scripts/trylink will
 133# take care of removing -lpthread if possible. (Not bothering to check
 134# CONFIG_STATIC because even in a non-static build it could be that the
 135# only libpam available is libpam.a, so -lpthread could still be
 136# needed.)
 137LDLIBS += pam pam_misc pthread
 138endif
 139
 140ifeq ($(CONFIG_SELINUX),y)
 141SELINUX_PC_MODULES = libselinux libsepol
 142$(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
 143CPPFLAGS += $(SELINUX_CFLAGS)
 144LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
 145endif
 146
 147ifeq ($(CONFIG_EFENCE),y)
 148LDLIBS += efence
 149endif
 150
 151ifeq ($(CONFIG_DMALLOC),y)
 152LDLIBS += dmalloc
 153endif
 154
 155# If a flat binary should be built, CFLAGS_busybox="-elf2flt"
 156# env var should be set for make invocation.
 157# Here we check whether CFLAGS_busybox indeed contains that flag.
 158# (For historical reasons, we also check LDFLAGS, which doesn't
 159# seem to be entirely correct variable to put "-elf2flt" into).
 160W_ELF2FLT = -elf2flt
 161ifneq (,$(findstring $(W_ELF2FLT),$(LDFLAGS) $(CFLAGS_busybox)))
 162SKIP_STRIP = y
 163endif
 164
 165ifneq ($(CONFIG_EXTRA_LDFLAGS),)
 166EXTRA_LDFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_LDFLAGS)))
 167#"))
 168endif
 169
 170ifneq ($(CONFIG_EXTRA_LDLIBS),)
 171LDLIBS += $(strip $(subst ",,$(CONFIG_EXTRA_LDLIBS)))
 172#"))
 173endif
 174
 175# Busybox is a stack-fatty so make sure we increase default size
 176# TODO: use "make stksizes" to find & fix big stack users
 177# (we stole scripts/checkstack.pl from the kernel... thanks guys!)
 178# Reduced from 20k to 16k in 1.9.0.
 179FLTFLAGS += -s 16000
 180