Makefile.flags 7.5 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 $(CONFIG_LFS),-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64) \
  15. -DBB_VER=$(squote)$(quote)$(BB_VER)$(quote)$(squote)
  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 += $(call cc-ifversion, -ge, 0400, -Wold-style-definition)
  44. ifneq ($(CC),clang)
  45. # "clang-9: warning: optimization flag '-finline-limit=0' is not supported
  46. CFLAGS += $(call cc-option,-finline-limit=0,)
  47. endif
  48. CFLAGS += $(call cc-option,-fno-builtin-strlen -fomit-frame-pointer -ffunction-sections -fdata-sections,)
  49. # -fno-guess-branch-probability: prohibit pseudo-random guessing
  50. # of branch probabilities (hopefully makes bloatcheck more stable):
  51. CFLAGS += $(call cc-option,-fno-guess-branch-probability,)
  52. CFLAGS += $(call cc-option,-funsigned-char,)
  53. ifneq ($(CC),clang)
  54. # "clang-9: warning: argument unused during compilation: '-static-libgcc'"
  55. CFLAGS += $(call cc-option,-static-libgcc,)
  56. endif
  57. CFLAGS += $(call cc-option,-falign-functions=1,)
  58. ifneq ($(CC),clang)
  59. # "clang-9: warning: optimization flag '-falign-jumps=1' is not supported" (and same for other two)
  60. CFLAGS += $(call cc-option,-falign-jumps=1 -falign-labels=1 -falign-loops=1,)
  61. endif
  62. # Defeat .eh_frame bloat (gcc 4.6.3 x86-32 defconfig: 20% smaller busybox binary):
  63. CFLAGS += $(call cc-option,-fno-unwind-tables,)
  64. CFLAGS += $(call cc-option,-fno-asynchronous-unwind-tables,)
  65. # No automatic printf->puts,putchar conversions
  66. # (try disabling this and comparing assembly, it's instructive)
  67. CFLAGS += $(call cc-option,-fno-builtin-printf,)
  68. # clang-9 does not like "str" + N and "if (CONFIG_ITEM && cond)" constructs
  69. CFLAGS += $(call cc-option,-Wno-string-plus-int -Wno-constant-logical-operand)
  70. # FIXME: These warnings are at least partially to be concerned about and should
  71. # be fixed..
  72. #CFLAGS += $(call cc-option,-Wconversion,)
  73. ifneq ($(CONFIG_DEBUG),y)
  74. CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  75. else
  76. CFLAGS += $(call cc-option,-g,)
  77. #CFLAGS += "-D_FORTIFY_SOURCE=2"
  78. ifeq ($(CONFIG_DEBUG_PESSIMIZE),y)
  79. CFLAGS += $(call cc-option,-O0,)
  80. else
  81. CFLAGS += $(call cc-option,-Os,$(call cc-option,-O2,))
  82. endif
  83. endif
  84. ifeq ($(CONFIG_DEBUG_SANITIZE),y)
  85. CFLAGS += $(call cc-option,-fsanitize=address,)
  86. CFLAGS += $(call cc-option,-fsanitize=leak,)
  87. CFLAGS += $(call cc-option,-fsanitize=undefined,)
  88. endif
  89. # If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)...
  90. ARCH_FPIC ?= -fpic
  91. ARCH_FPIE ?= -fpie
  92. ARCH_PIE ?= -pie
  93. # Usage: $(eval $(call pkg_check_modules,VARIABLE-PREFIX,MODULES))
  94. define pkg_check_modules
  95. $(1)_CFLAGS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --cflags $(2))
  96. $(1)_LIBS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --libs $(2))
  97. endef
  98. ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
  99. # on i386: 14% smaller libbusybox.so
  100. # (code itself is 9% bigger, we save on relocs/PLT/GOT)
  101. CFLAGS += $(ARCH_FPIC)
  102. # and another 4% reduction of libbusybox.so:
  103. # (external entry points must be marked EXTERNALLY_VISIBLE)
  104. CFLAGS += $(call cc-option,-fvisibility=hidden)
  105. endif
  106. ifeq ($(CONFIG_STATIC),y)
  107. CFLAGS_busybox += -static
  108. PKG_CONFIG_FLAGS += --static
  109. endif
  110. ifeq ($(CONFIG_PIE),y)
  111. CFLAGS_busybox += $(ARCH_PIE)
  112. CFLAGS += $(ARCH_FPIE)
  113. endif
  114. ifneq ($(CONFIG_EXTRA_CFLAGS),)
  115. CFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_CFLAGS)))
  116. #"))
  117. endif
  118. # Note: both "" (string consisting of two quote chars) and empty string
  119. # are possible, and should be skipped below.
  120. ifneq ($(subst "",,$(CONFIG_SYSROOT)),)
  121. CFLAGS += --sysroot=$(CONFIG_SYSROOT)
  122. export SYSROOT=$(CONFIG_SYSROOT)
  123. endif
  124. # Android has no separate crypt library
  125. # gcc-4.2.1 fails if we try to feed C source on stdin:
  126. # echo 'int main(void){return 0;}' | $(CC) $(CFLAGS) -lcrypt -o /dev/null -xc -
  127. # fall back to using a temp file:
  128. CRYPT_AVAILABLE := $(shell echo 'int main(void){return 0;}' >crypttest.c; $(CC) $(CFLAGS) -lcrypt -o /dev/null crypttest.c >/dev/null 2>&1 && echo "y"; rm crypttest.c)
  129. ifeq ($(CRYPT_AVAILABLE),y)
  130. LDLIBS += m rt crypt
  131. else
  132. LDLIBS += m rt
  133. endif
  134. # libm may be needed for dc, awk, ntpd
  135. # librt may be needed for clock_gettime()
  136. # libpam may use libpthread, libdl and/or libaudit.
  137. # On some platforms that requires an explicit -lpthread, -ldl, -laudit.
  138. # However, on *other platforms* it fails when some of those flags
  139. # given needlessly. On some systems, crypt needs pthread.
  140. #
  141. # I even had a system where a runtime test for pthread
  142. # (similar to CRYPT_AVAILABLE test above) was not reliable.
  143. #
  144. # Do not propagate this mess by adding libraries to CONFIG_PAM/CRYPT_AVAILABLE blocks.
  145. # Add libraries you need to CONFIG_EXTRA_LDLIBS instead.
  146. ifeq ($(CONFIG_PAM),y)
  147. LDLIBS += pam pam_misc
  148. endif
  149. ifeq ($(CONFIG_SELINUX),y)
  150. SELINUX_PC_MODULES = libselinux libsepol
  151. $(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
  152. CPPFLAGS += $(SELINUX_CFLAGS)
  153. LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
  154. endif
  155. ifeq ($(CONFIG_FEATURE_NSLOOKUP_BIG),y)
  156. LDLIBS += resolv
  157. endif
  158. ifeq ($(CONFIG_EFENCE),y)
  159. LDLIBS += efence
  160. endif
  161. ifeq ($(CONFIG_DMALLOC),y)
  162. LDLIBS += dmalloc
  163. endif
  164. # If a flat binary should be built, CFLAGS_busybox="-elf2flt"
  165. # env var should be set for make invocation.
  166. # Here we check whether CFLAGS_busybox indeed contains that flag.
  167. # (For historical reasons, we also check LDFLAGS, which doesn't
  168. # seem to be entirely correct variable to put "-elf2flt" into).
  169. W_ELF2FLT = -elf2flt
  170. ifneq (,$(findstring $(W_ELF2FLT),$(LDFLAGS) $(CFLAGS_busybox)))
  171. SKIP_STRIP = y
  172. endif
  173. ifneq ($(CONFIG_EXTRA_LDFLAGS),)
  174. LDFLAGS += $(strip $(subst ",,$(CONFIG_EXTRA_LDFLAGS)))
  175. #"))
  176. endif
  177. ifneq ($(CONFIG_EXTRA_LDLIBS),)
  178. LDLIBS += $(strip $(subst ",,$(CONFIG_EXTRA_LDLIBS)))
  179. #"))
  180. endif
  181. # Busybox is a stack-fatty so make sure we increase default size
  182. # TODO: use "make stksizes" to find & fix big stack users
  183. # (we stole scripts/checkstack.pl from the kernel... thanks guys!)
  184. # Reduced from 20k to 16k in 1.9.0.
  185. FLTFLAGS += -s 16000