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Makefile.flags 6.8 KB

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  1. # ==========================================================================
  2. # Build system
  3. # ==========================================================================
  4. BB_VER = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
  5. export BB_VER
  6. SKIP_STRIP ?= n
  7. # -std=gnu99 needed for [U]LLONG_MAX on some systems
  8. CPPFLAGS += $(call cc-option,-std=gnu99,)
  9. CPPFLAGS += \
  10. -Iinclude -Ilibbb \
  11. $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include -I$(srctree)/libbb) \
  12. -include include/autoconf.h \
  13. -D_GNU_SOURCE -DNDEBUG \
  14. $(if $(CONFIG_LFS),-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64) \
  15. -D"BB_VER=KBUILD_STR($(BB_VER))"
  16. CFLAGS += $(call cc-option,-Wall,)
  17. CFLAGS += $(call cc-option,-Wshadow,)
  18. CFLAGS += $(call cc-option,-Wwrite-strings,)
  19. CFLAGS += $(call cc-option,-Wundef,)
  20. CFLAGS += $(call cc-option,-Wstrict-prototypes,)
  21. CFLAGS += $(call cc-option,-Wunused -Wunused-parameter,)
  22. CFLAGS += $(call cc-option,-Wunused-function -Wunused-value,)
  23. CFLAGS += $(call cc-option,-Wmissing-prototypes -Wmissing-declarations,)
  24. CFLAGS += $(call cc-option,-Wno-format-security,)
  25. # warn about C99 declaration after statement
  26. CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
  27. # If you want to add more -Wsomething above, make sure that it is
  28. # still possible to build bbox without warnings.
  29. ifeq ($(CONFIG_WERROR),y)
  30. CFLAGS += $(call cc-option,-Werror,)
  31. ## TODO:
  32. ## gcc version 4.4.0 20090506 (Red Hat 4.4.0-4) (GCC) is a PITA:
  33. ## const char *ptr; ... off_t v = *(off_t*)ptr; -> BOOM
  34. ## and no easy way to convince it to shut the hell up.
  35. ## We have a lot of such things all over the place.
  36. ## Classic *(off_t*)(void*)ptr does not work,
  37. ## and I am unwilling to do crazy gcc specific ({ void *ppp = ...; })
  38. ## stuff in macros. This would obfuscate the code too much.
  39. ## Maybe try __attribute__((__may_alias__))?
  40. #CFLAGS += $(call cc-ifversion, -eq, 0404, -fno-strict-aliasing)
  41. endif
  42. # gcc 3.x emits bogus "old style proto" warning on find.c:alloc_action()
  43. CFLAGS += $(call cc-ifversion, -ge, 0400, -Wold-style-definition)
  44. CFLAGS += $(call cc-option,-fno-builtin-strlen -finline-limit=0 -fomit-frame-pointer -ffunction-sections -fdata-sections,)
  45. # -fno-guess-branch-probability: prohibit pseudo-random guessing
  46. # of branch probabilities (hopefully makes bloatcheck more stable):
  47. CFLAGS += $(call cc-option,-fno-guess-branch-probability,)
  48. CFLAGS += $(call cc-option,-funsigned-char -static-libgcc,)
  49. CFLAGS += $(call cc-option,-falign-functions=1 -falign-jumps=1 -falign-labels=1 -falign-loops=1,)
  50. # Defeat .eh_frame bloat (gcc 4.6.3 x86-32 defconfig: 20% smaller busybox binary):
  51. CFLAGS += $(call cc-option,-fno-unwind-tables,)
  52. CFLAGS += $(call cc-option,-fno-asynchronous-unwind-tables,)
  53. # No automatic printf->puts,putchar conversions
  54. # (try disabling this and comparing assembly, it's instructive)
  55. CFLAGS += $(call cc-option,-fno-builtin-printf,)
  56. # FIXME: These warnings are at least partially to be concerned about and should
  57. # be fixed..
  58. #CFLAGS += $(call cc-option,-Wconversion,)
  59. ifneq ($(CONFIG_DEBUG),y)
  60. CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  61. else
  62. CFLAGS += $(call cc-option,-g,)
  63. #CFLAGS += "-D_FORTIFY_SOURCE=2"
  64. ifeq ($(CONFIG_DEBUG_PESSIMIZE),y)
  65. CFLAGS += $(call cc-option,-O0,)
  66. else
  67. CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  68. endif
  69. endif
  70. ifeq ($(CONFIG_DEBUG_SANITIZE),y)
  71. CFLAGS += $(call cc-option,-fsanitize=address,)
  72. CFLAGS += $(call cc-option,-fsanitize=leak,)
  73. CFLAGS += $(call cc-option,-fsanitize=undefined,)
  74. endif
  75. # If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)...
  76. ARCH_FPIC ?= -fpic
  77. ARCH_FPIE ?= -fpie
  78. ARCH_PIE ?= -pie
  79. # Usage: $(eval $(call pkg_check_modules,VARIABLE-PREFIX,MODULES))
  80. define pkg_check_modules
  81. $(1)_CFLAGS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --cflags $(2))
  82. $(1)_LIBS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --libs $(2))
  83. endef
  84. ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
  85. # on i386: 14% smaller libbusybox.so
  86. # (code itself is 9% bigger, we save on relocs/PLT/GOT)
  87. CFLAGS += $(ARCH_FPIC)
  88. # and another 4% reduction of libbusybox.so:
  89. # (external entry points must be marked EXTERNALLY_VISIBLE)
  90. CFLAGS += $(call cc-option,-fvisibility=hidden)
  91. endif
  92. ifeq ($(CONFIG_STATIC),y)
  93. CFLAGS_busybox += -static
  94. PKG_CONFIG_FLAGS += --static
  95. endif
  96. ifeq ($(CONFIG_PIE),y)
  97. CFLAGS_busybox += $(ARCH_PIE)
  98. CFLAGS += $(ARCH_FPIE)
  99. endif
  100. ifneq ($(CONFIG_EXTRA_CFLAGS),)
  101. CFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_CFLAGS)))
  102. #"))
  103. endif
  104. # Note: both "" (string consisting of two quote chars) and empty string
  105. # are possible, and should be skipped below.
  106. ifneq ($(subst "",,$(CONFIG_SYSROOT)),)
  107. CFLAGS += --sysroot=$(CONFIG_SYSROOT)
  108. export SYSROOT=$(CONFIG_SYSROOT)
  109. endif
  110. # Android has no separate crypt library
  111. # gcc-4.2.1 fails if we try to feed C source on stdin:
  112. # echo 'int main(void){return 0;}' | $(CC) $(CFLAGS) -lcrypt -o /dev/null -xc -
  113. # fall back to using a temp file:
  114. CRYPT_AVAILABLE := $(shell echo 'int main(void){return 0;}' >crypttest.c; $(CC) $(CFLAGS) -lcrypt -o /dev/null crypttest.c >/dev/null 2>&1 && echo "y"; rm crypttest.c)
  115. ifeq ($(CRYPT_AVAILABLE),y)
  116. LDLIBS += m crypt
  117. else
  118. LDLIBS += m
  119. endif
  120. # libpam may use libpthread, libdl and/or libaudit.
  121. # On some platforms that requires an explicit -lpthread, -ldl, -laudit.
  122. # However, on *other platforms* it fails when some of those flags
  123. # given needlessly. On some systems, crypt needs pthread.
  124. #
  125. # I even had a system where a runtime test for pthread
  126. # (similar to CRYPT_AVAILABLE test above) was not reliable.
  127. #
  128. # Do not propagate this mess by adding libraries to CONFIG_PAM/CRYPT_AVAILABLE blocks.
  129. # Add libraries you need to CONFIG_EXTRA_LDLIBS instead.
  130. ifeq ($(CONFIG_PAM),y)
  131. LDLIBS += pam pam_misc
  132. endif
  133. ifeq ($(CONFIG_SELINUX),y)
  134. SELINUX_PC_MODULES = libselinux libsepol
  135. $(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
  136. CPPFLAGS += $(SELINUX_CFLAGS)
  137. LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
  138. endif
  139. ifeq ($(CONFIG_FEATURE_NSLOOKUP_BIG),y)
  140. LDLIBS += resolv
  141. endif
  142. ifeq ($(CONFIG_EFENCE),y)
  143. LDLIBS += efence
  144. endif
  145. ifeq ($(CONFIG_DMALLOC),y)
  146. LDLIBS += dmalloc
  147. endif
  148. # If a flat binary should be built, CFLAGS_busybox="-elf2flt"
  149. # env var should be set for make invocation.
  150. # Here we check whether CFLAGS_busybox indeed contains that flag.
  151. # (For historical reasons, we also check LDFLAGS, which doesn't
  152. # seem to be entirely correct variable to put "-elf2flt" into).
  153. W_ELF2FLT = -elf2flt
  154. ifneq (,$(findstring $(W_ELF2FLT),$(LDFLAGS) $(CFLAGS_busybox)))
  155. SKIP_STRIP = y
  156. endif
  157. ifneq ($(CONFIG_EXTRA_LDFLAGS),)
  158. LDFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_LDFLAGS)))
  159. #"))
  160. endif
  161. ifneq ($(CONFIG_EXTRA_LDLIBS),)
  162. LDLIBS += $(strip $(subst ",,$(CONFIG_EXTRA_LDLIBS)))
  163. #"))
  164. endif
  165. # Busybox is a stack-fatty so make sure we increase default size
  166. # TODO: use "make stksizes" to find & fix big stack users
  167. # (we stole scripts/checkstack.pl from the kernel... thanks guys!)
  168. # Reduced from 20k to 16k in 1.9.0.
  169. FLTFLAGS += -s 16000