$ clang -dM -E -arch armv7 -x c /dev/null
#define OBJC_NEW_PROPERTIES 1
#define __APCS_32__ 1
#define __APPLE_CC__ 6000
#define __APPLE__ 1
#define __ARMEL__ 1
#define __ARM_ARCH 7
#define __ARM_ARCH_7A__ 1
#define __ARM_ARCH_PROFILE A
#define __ARM_NEON__ 1
#define __ARM_VFPV3__ 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_CONSUME 1
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BLOCKS__ 1
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ unsigned short
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __CONSTANT_CFSTRINGS__ 1
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ 2.2204460492503131e-16
#define __DBL_HAS_DENORM__ 1
#define __DBL_HAS_INFINITY__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __DBL_MANT_DIG__ 53
#define __DBL_MAX_10_EXP__ 308
#define __DBL_MAX_EXP__ 1024
#define __DBL_MAX__ 1.7976931348623157e+308
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN__ 2.2250738585072014e-308
#define __DECIMAL_DIG__ 17
#define __DYNAMIC__ 1
#define __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ 50000
#define __FINITE_MATH_ONLY__ 0
#define __FLT_DENORM_MIN__ 1.40129846e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209290e-7F
#define __FLT_EVAL_METHOD__ 0
#define __FLT_HAS_DENORM__ 1
#define __FLT_HAS_INFINITY__ 1
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MANT_DIG__ 24
#define __FLT_MAX_10_EXP__ 38
#define __FLT_MAX_EXP__ 128
#define __FLT_MAX__ 3.40282347e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN__ 1.17549435e-38F
#define __FLT_RADIX__ 2
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GNUC_MINOR__ 2
#define __GNUC_PATCHLEVEL__ 1
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 4
#define __GXX_ABI_VERSION 1002
#define __GXX_RTTI 1
#define __INT16_TYPE__ short
#define __INT32_TYPE__ int
#define __INT64_C_SUFFIX__ LL
#define __INT64_TYPE__ long long int
#define __INT8_TYPE__ char
#define __INTMAX_MAX__ 9223372036854775807LL
#define __INTMAX_TYPE__ long long int
#define __INTMAX_WIDTH__ 64
#define __INTPTR_TYPE__ long int
#define __INTPTR_WIDTH__ 32
#define __INT_MAX__ 2147483647
#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
#define __LDBL_DIG__ 15
#define __LDBL_EPSILON__ 2.2204460492503131e-16L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 53
#define __LDBL_MAX_10_EXP__ 308
#define __LDBL_MAX_EXP__ 1024
#define __LDBL_MAX__ 1.7976931348623157e+308L
#define __LDBL_MIN_10_EXP__ (-307)
#define __LDBL_MIN_EXP__ (-1021)
#define __LDBL_MIN__ 2.2250738585072014e-308L
#define __LITTLE_ENDIAN__ 1
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __LONG_MAX__ 2147483647L
#define __MACH__ 1
#define __NO_INLINE__ 1
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PIC__ 2
#define __POINTER_WIDTH__ 32
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_TYPE__ int
#define __PTRDIFF_WIDTH__ 32
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 127
#define __SHRT_MAX__ 32767
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT__ 4
#define __SIZEOF_INT__ 4
#define __SIZEOF_LONG_DOUBLE__ 8
#define __SIZEOF_LONG_LONG__ 8
#define __SIZEOF_LONG__ 4
#define __SIZEOF_POINTER__ 4
#define __SIZEOF_PTRDIFF_T__ 4
#define __SIZEOF_SHORT__ 2
#define __SIZEOF_SIZE_T__ 4
#define __SIZEOF_WCHAR_T__ 4
#define __SIZEOF_WINT_T__ 4
#define __SIZE_MAX__ 4294967295UL
#define __SIZE_TYPE__ long unsigned int
#define __SIZE_WIDTH__ 32
#define __SSP__ 1
#define __STDC_HOSTED__ 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 199901L
#define __STDC__ 1
#define __THUMBEL__ 1
#define __THUMB_INTERWORK__ 1
#define __UINTMAX_TYPE__ long long unsigned int
#define __USER_LABEL_PREFIX__ _
#define __USING_SJLJ_EXCEPTIONS__ 1
#define __VERSION__ "4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)"
#define __VFP_FP__ 1
#define __WCHAR_MAX__ 2147483647
#define __WCHAR_TYPE__ int
#define __WCHAR_WIDTH__ 32
#define __WINT_TYPE__ int
#define __WINT_WIDTH__ 32
#define __apple_build_version__ 5030040
#define __arm 1
#define __arm__ 1
#define __block __attribute__((__blocks__(byref)))
#define __clang__ 1
#define __clang_major__ 5
#define __clang_minor__ 1
#define __clang_patchlevel__ 0
#define __clang_version__ "5.1 (clang-503.0.40)"
#define __llvm__ 1
#define __pic__ 2
#define __strong
#define __thumb2__ 1
#define __thumb__ 1
#define __unsafe_unretained
#define __weak __attribute__((objc_gc(weak)))
$ clang -dM -E -arch armv7s -x c /dev/null
#define OBJC_NEW_PROPERTIES 1
#define __APCS_32__ 1
#define __APPLE_CC__ 6000
#define __APPLE__ 1
#define __ARMEL__ 1
#define __ARM_ARCH 7
#define __ARM_ARCH_7S__ 1
#define __ARM_ARCH_EXT_IDIV__ 1
#define __ARM_NEON__ 1
#define __ARM_VFPV4__ 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_CONSUME 1
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BLOCKS__ 1
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ unsigned short
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __CONSTANT_CFSTRINGS__ 1
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ 2.2204460492503131e-16
#define __DBL_HAS_DENORM__ 1
#define __DBL_HAS_INFINITY__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __DBL_MANT_DIG__ 53
#define __DBL_MAX_10_EXP__ 308
#define __DBL_MAX_EXP__ 1024
#define __DBL_MAX__ 1.7976931348623157e+308
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN__ 2.2250738585072014e-308
#define __DECIMAL_DIG__ 17
#define __DYNAMIC__ 1
#define __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ 50000
#define __FINITE_MATH_ONLY__ 0
#define __FLT_DENORM_MIN__ 1.40129846e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209290e-7F
#define __FLT_EVAL_METHOD__ 0
#define __FLT_HAS_DENORM__ 1
#define __FLT_HAS_INFINITY__ 1
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MANT_DIG__ 24
#define __FLT_MAX_10_EXP__ 38
#define __FLT_MAX_EXP__ 128
#define __FLT_MAX__ 3.40282347e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN__ 1.17549435e-38F
#define __FLT_RADIX__ 2
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __GCC_ATOMIC_LLONG_LOCK_FREE 1
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GNUC_MINOR__ 2
#define __GNUC_PATCHLEVEL__ 1
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 4
#define __GXX_ABI_VERSION 1002
#define __GXX_RTTI 1
#define __INT16_TYPE__ short
#define __INT32_TYPE__ int
#define __INT64_C_SUFFIX__ LL
#define __INT64_TYPE__ long long int
#define __INT8_TYPE__ char
#define __INTMAX_MAX__ 9223372036854775807LL
#define __INTMAX_TYPE__ long long int
#define __INTMAX_WIDTH__ 64
#define __INTPTR_TYPE__ long int
#define __INTPTR_WIDTH__ 32
#define __INT_MAX__ 2147483647
#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
#define __LDBL_DIG__ 15
#define __LDBL_EPSILON__ 2.2204460492503131e-16L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 53
#define __LDBL_MAX_10_EXP__ 308
#define __LDBL_MAX_EXP__ 1024
#define __LDBL_MAX__ 1.7976931348623157e+308L
#define __LDBL_MIN_10_EXP__ (-307)
#define __LDBL_MIN_EXP__ (-1021)
#define __LDBL_MIN__ 2.2250738585072014e-308L
#define __LITTLE_ENDIAN__ 1
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __LONG_MAX__ 2147483647L
#define __MACH__ 1
#define __NO_INLINE__ 1
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PIC__ 2
#define __POINTER_WIDTH__ 32
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_TYPE__ int
#define __PTRDIFF_WIDTH__ 32
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 127
#define __SHRT_MAX__ 32767
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT__ 4
#define __SIZEOF_INT__ 4
#define __SIZEOF_LONG_DOUBLE__ 8
#define __SIZEOF_LONG_LONG__ 8
#define __SIZEOF_LONG__ 4
#define __SIZEOF_POINTER__ 4
#define __SIZEOF_PTRDIFF_T__ 4
#define __SIZEOF_SHORT__ 2
#define __SIZEOF_SIZE_T__ 4
#define __SIZEOF_WCHAR_T__ 4
#define __SIZEOF_WINT_T__ 4
#define __SIZE_MAX__ 4294967295UL
#define __SIZE_TYPE__ long unsigned int
#define __SIZE_WIDTH__ 32
#define __SSP__ 1
#define __STDC_HOSTED__ 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 199901L
#define __STDC__ 1
#define __THUMBEL__ 1
#define __THUMB_INTERWORK__ 1
#define __UINTMAX_TYPE__ long long unsigned int
#define __USER_LABEL_PREFIX__ _
#define __USING_SJLJ_EXCEPTIONS__ 1
#define __VERSION__ "4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)"
#define __VFP_FP__ 1
#define __WCHAR_MAX__ 2147483647
#define __WCHAR_TYPE__ int
#define __WCHAR_WIDTH__ 32
#define __WINT_TYPE__ int
#define __WINT_WIDTH__ 32
#define __apple_build_version__ 5030040
#define __arm 1
#define __arm__ 1
#define __block __attribute__((__blocks__(byref)))
#define __clang__ 1
#define __clang_major__ 5
#define __clang_minor__ 1
#define __clang_patchlevel__ 0
#define __clang_version__ "5.1 (clang-503.0.40)"
#define __llvm__ 1
#define __pic__ 2
#define __strong
#define __thumb2__ 1
#define __thumb__ 1
#define __unsafe_unretained
#define __weak __attribute__((objc_gc(weak)))
$ clang -dM -E -arch arm64 -x c /dev/null
#define OBJC_NEW_PROPERTIES 1
#define _LP64 1
#define __AARCH64_SIMD__ 1
#define __APPLE_CC__ 6000
#define __APPLE__ 1
#define __ARM64_ARCH_8__ 1
#define __ARM_NEON__ 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_CONSUME 1
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BLOCKS__ 1
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ unsigned short
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __CONSTANT_CFSTRINGS__ 1
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ 2.2204460492503131e-16
#define __DBL_HAS_DENORM__ 1
#define __DBL_HAS_INFINITY__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __DBL_MANT_DIG__ 53
#define __DBL_MAX_10_EXP__ 308
#define __DBL_MAX_EXP__ 1024
#define __DBL_MAX__ 1.7976931348623157e+308
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN__ 2.2250738585072014e-308
#define __DECIMAL_DIG__ 17
#define __DYNAMIC__ 1
#define __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ 50000
#define __FINITE_MATH_ONLY__ 0
#define __FLT_DENORM_MIN__ 1.40129846e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209290e-7F
#define __FLT_EVAL_METHOD__ 0
#define __FLT_HAS_DENORM__ 1
#define __FLT_HAS_INFINITY__ 1
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MANT_DIG__ 24
#define __FLT_MAX_10_EXP__ 38
#define __FLT_MAX_EXP__ 128
#define __FLT_MAX__ 3.40282347e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN__ 1.17549435e-38F
#define __FLT_RADIX__ 2
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __GNUC_MINOR__ 2
#define __GNUC_PATCHLEVEL__ 1
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 4
#define __GXX_ABI_VERSION 1002
#define __GXX_RTTI 1
#define __INT16_TYPE__ short
#define __INT32_TYPE__ int
#define __INT64_C_SUFFIX__ LL
#define __INT64_TYPE__ long long int
#define __INT8_TYPE__ char
#define __INTMAX_MAX__ 9223372036854775807L
#define __INTMAX_TYPE__ long int
#define __INTMAX_WIDTH__ 64
#define __INTPTR_TYPE__ long int
#define __INTPTR_WIDTH__ 64
#define __INT_MAX__ 2147483647
#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
#define __LDBL_DIG__ 15
#define __LDBL_EPSILON__ 2.2204460492503131e-16L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 53
#define __LDBL_MAX_10_EXP__ 308
#define __LDBL_MAX_EXP__ 1024
#define __LDBL_MAX__ 1.7976931348623157e+308L
#define __LDBL_MIN_10_EXP__ (-307)
#define __LDBL_MIN_EXP__ (-1021)
#define __LDBL_MIN__ 2.2250738585072014e-308L
#define __LITTLE_ENDIAN__ 1
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __LONG_MAX__ 9223372036854775807L
#define __LP64__ 1
#define __MACH__ 1
#define __NO_INLINE__ 1
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PIC__ 2
#define __POINTER_WIDTH__ 64
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_TYPE__ long int
#define __PTRDIFF_WIDTH__ 64
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 127
#define __SHRT_MAX__ 32767
#define __SIG_ATOMIC_WIDTH__ 32
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT__ 4
#define __SIZEOF_INT128__ 16
#define __SIZEOF_INT__ 4
#define __SIZEOF_LONG_DOUBLE__ 8
#define __SIZEOF_LONG_LONG__ 8
#define __SIZEOF_LONG__ 8
#define __SIZEOF_POINTER__ 8
#define __SIZEOF_PTRDIFF_T__ 8
#define __SIZEOF_SHORT__ 2
#define __SIZEOF_SIZE_T__ 8
#define __SIZEOF_WCHAR_T__ 4
#define __SIZEOF_WINT_T__ 4
#define __SIZE_MAX__ 18446744073709551615UL
#define __SIZE_TYPE__ long unsigned int
#define __SIZE_WIDTH__ 64
#define __SSP__ 1
#define __STDC_HOSTED__ 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 199901L
#define __STDC__ 1
#define __UINTMAX_TYPE__ long unsigned int
#define __USER_LABEL_PREFIX__ _
#define __VERSION__ "4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)"
#define __WCHAR_MAX__ 2147483647
#define __WCHAR_TYPE__ int
#define __WCHAR_WIDTH__ 32
#define __WINT_TYPE__ int
#define __WINT_WIDTH__ 32
#define __aarch64__ 1
#define __apple_build_version__ 5030040
#define __arm64 1
#define __arm64__ 1
#define __block __attribute__((__blocks__(byref)))
#define __clang__ 1
#define __clang_major__ 5
#define __clang_minor__ 1
#define __clang_patchlevel__ 0
#define __clang_version__ "5.1 (clang-503.0.40)"
#define __llvm__ 1
#define __pic__ 2
#define __strong
#define __unsafe_unretained
#define __weak __attribute__((objc_gc(weak)))
xcode 编译器在各个arch下面默认宏