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))"
  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# No automatic printf->puts,putchar conversions
  60# (try disabling this and comparing assembly, it's instructive)
  61CFLAGS += $(call cc-option,-fno-builtin-printf,)
  62
  63# FIXME: These warnings are at least partially to be concerned about and should
  64# be fixed..
  65#CFLAGS += $(call cc-option,-Wconversion,)
  66
  67ifneq ($(CONFIG_DEBUG),y)
  68CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  69else
  70CFLAGS += $(call cc-option,-g,)
  71#CFLAGS += "-D_FORTIFY_SOURCE=2"
  72ifeq ($(CONFIG_DEBUG_PESSIMIZE),y)
  73CFLAGS += $(call cc-option,-O0,)
  74else
  75CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  76endif
  77endif
  78ifeq ($(CONFIG_DEBUG_SANITIZE),y)
  79CFLAGS += $(call cc-option,-fsanitize=address,)
  80CFLAGS += $(call cc-option,-fsanitize=leak,)
  81CFLAGS += $(call cc-option,-fsanitize=undefined,)
  82endif
  83
  84# If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)...
  85ARCH_FPIC ?= -fpic
  86ARCH_FPIE ?= -fpie
  87ARCH_PIE ?= -pie
  88
  89# Usage: $(eval $(call pkg_check_modules,VARIABLE-PREFIX,MODULES))
  90define pkg_check_modules
  91$(1)_CFLAGS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --cflags $(2))
  92$(1)_LIBS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --libs $(2))
  93endef
  94
  95ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
  96# on i386: 14% smaller libbusybox.so
  97# (code itself is 9% bigger, we save on relocs/PLT/GOT)
  98CFLAGS += $(ARCH_FPIC)
  99# and another 4% reduction of libbusybox.so:
 100# (external entry points must be marked EXTERNALLY_VISIBLE)
 101CFLAGS += $(call cc-option,-fvisibility=hidden)
 102endif
 103
 104ifeq ($(CONFIG_STATIC),y)
 105CFLAGS_busybox += -static
 106PKG_CONFIG_FLAGS += --static
 107endif
 108
 109ifeq ($(CONFIG_PIE),y)
 110CFLAGS_busybox += $(ARCH_PIE)
 111CFLAGS += $(ARCH_FPIE)
 112endif
 113
 114ifneq ($(CONFIG_EXTRA_CFLAGS),)
 115CFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_CFLAGS)))
 116#"))
 117endif
 118
 119# Note: both "" (string consisting of two quote chars) and empty string
 120# are possible, and should be skipped below.
 121ifneq ($(subst "",,$(CONFIG_SYSROOT)),)
 122CFLAGS += --sysroot=$(CONFIG_SYSROOT)
 123export SYSROOT=$(CONFIG_SYSROOT)
 124endif
 125
 126# Android has no separate crypt library
 127# gcc-4.2.1 fails if we try to feed C source on stdin:
 128#  echo 'int main(void){return 0;}' | $(CC) $(CFLAGS) -lcrypt -o /dev/null -xc -
 129# fall back to using a temp file:
 130CRYPT_AVAILABLE := $(shell echo 'int main(void){return 0;}' >crypttest.c; $(CC) $(CFLAGS) -lcrypt -o /dev/null crypttest.c >/dev/null 2>&1 && echo "y"; rm crypttest.c)
 131ifeq ($(CRYPT_AVAILABLE),y)
 132LDLIBS += m crypt
 133else
 134LDLIBS += m
 135endif
 136
 137# libpam may use libpthread, libdl and/or libaudit.
 138# On some platforms that requires an explicit -lpthread, -ldl, -laudit.
 139# However, on *other platforms* it fails when some of those flags
 140# given needlessly. On some systems, crypt needs pthread.
 141#
 142# I even had a system where a runtime test for pthread
 143# (similar to CRYPT_AVAILABLE test above) was not reliable.
 144#
 145# Do not propagate this mess by adding libraries to CONFIG_PAM/CRYPT_AVAILABLE blocks.
 146# Add libraries you need to CONFIG_EXTRA_LDLIBS instead.
 147
 148ifeq ($(CONFIG_PAM),y)
 149LDLIBS += pam pam_misc
 150endif
 151
 152ifeq ($(CONFIG_SELINUX),y)
 153SELINUX_PC_MODULES = libselinux libsepol
 154$(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
 155CPPFLAGS += $(SELINUX_CFLAGS)
 156LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
 157endif
 158
 159ifeq ($(CONFIG_EFENCE),y)
 160LDLIBS += efence
 161endif
 162
 163ifeq ($(CONFIG_DMALLOC),y)
 164LDLIBS += dmalloc
 165endif
 166
 167# If a flat binary should be built, CFLAGS_busybox="-elf2flt"
 168# env var should be set for make invocation.
 169# Here we check whether CFLAGS_busybox indeed contains that flag.
 170# (For historical reasons, we also check LDFLAGS, which doesn't
 171# seem to be entirely correct variable to put "-elf2flt" into).
 172W_ELF2FLT = -elf2flt
 173ifneq (,$(findstring $(W_ELF2FLT),$(LDFLAGS) $(CFLAGS_busybox)))
 174SKIP_STRIP = y
 175endif
 176
 177ifneq ($(CONFIG_EXTRA_LDFLAGS),)
 178LDFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_LDFLAGS)))
 179#"))
 180endif
 181
 182ifneq ($(CONFIG_EXTRA_LDLIBS),)
 183LDLIBS += $(strip $(subst ",,$(CONFIG_EXTRA_LDLIBS)))
 184#"))
 185endif
 186
 187# Busybox is a stack-fatty so make sure we increase default size
 188# TODO: use "make stksizes" to find & fix big stack users
 189# (we stole scripts/checkstack.pl from the kernel... thanks guys!)
 190# Reduced from 20k to 16k in 1.9.0.
 191FLTFLAGS += -s 16000
 192