如何檢測預處理器中的X32 ABI或環境？

Question

X32是一個用於amd64/x86_64的ABI使用32位指針的CPU。我們的想法是將更大的x86_64寄存器組與由32位指針產生的更小的內存和高速緩存足跡結合起來。它提供了高達約40％的加速。有關詳細信息，請參閱Stack Overflow上的Difference between x86, x32, and x64 architectures和Debian X32 Ports wiki頁面，並將其設置爲chroot環境。

我們從環境下的Debian維護者處獲得一個錯誤報告。該報告是adcq是非法指令。內聯彙編是基於預處理器宏激活的，所以我們沒有正確檢測到X32（或者更正確，直到現在根本沒有檢測到）。

對於預處理器宏，最明顯的選擇就像__X32__，但沒有提供。基於Clang's patch和Debian's suggestion，它看起來像__ILP32__可以使用。但我想要更正規的答案，因爲_ILP32和__code_model_small__看起來也很有趣。 （我知道SSE2的問題，編譯器支持它，但操作系統沒有）。

在使用Clang和GCC時，可用於可靠檢測X32 ABI和環境的預處理器宏是什麼？

要說清楚，我並沒有試圖在這一點上修復代碼。我只想知道可以在完整補救中使用的宏。

---

# cpp -dM < /dev/null | sort 
#define __amd64 1 
#define __amd64__ 1 
#define __ATOMIC_ACQ_REL 4 
#define __ATOMIC_ACQUIRE 2 
#define __ATOMIC_CONSUME 1 
#define __ATOMIC_HLE_ACQUIRE 65536 
#define __ATOMIC_HLE_RELEASE 131072 
#define __ATOMIC_RELAXED 0 
#define __ATOMIC_RELEASE 3 
#define __ATOMIC_SEQ_CST 5 
#define __BIGGEST_ALIGNMENT__ 16 
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ 
#define __CHAR16_TYPE__ short unsigned int 
#define __CHAR32_TYPE__ unsigned int 
#define __CHAR_BIT__ 8 
#define __code_model_small__ 1 
#define __DBL_DECIMAL_DIG__ 17 
#define __DBL_DENORM_MIN__ ((double)4.94065645841246544177e-324L) 
#define __DBL_DIG__ 15 
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-16L) 
#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__ ((double)1.79769313486231570815e+308L) 
#define __DBL_MAX_EXP__ 1024 
#define __DBL_MIN_10_EXP__ (-307) 
#define __DBL_MIN__ ((double)2.22507385850720138309e-308L) 
#define __DBL_MIN_EXP__ (-1021) 
#define __DEC128_EPSILON__ 1E-33DL 
#define __DEC128_MANT_DIG__ 34 
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL 
#define __DEC128_MAX_EXP__ 6145 
#define __DEC128_MIN__ 1E-6143DL 
#define __DEC128_MIN_EXP__ (-6142) 
#define __DEC128_SUBNORMAL_MIN__ 0.000000000000000000000000000000001E-6143DL 
#define __DEC32_EPSILON__ 1E-6DF 
#define __DEC32_MANT_DIG__ 7 
#define __DEC32_MAX__ 9.999999E96DF 
#define __DEC32_MAX_EXP__ 97 
#define __DEC32_MIN__ 1E-95DF 
#define __DEC32_MIN_EXP__ (-94) 
#define __DEC32_SUBNORMAL_MIN__ 0.000001E-95DF 
#define __DEC64_EPSILON__ 1E-15DD 
#define __DEC64_MANT_DIG__ 16 
#define __DEC64_MAX__ 9.999999999999999E384DD 
#define __DEC64_MAX_EXP__ 385 
#define __DEC64_MIN__ 1E-383DD 
#define __DEC64_MIN_EXP__ (-382) 
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD 
#define __DEC_EVAL_METHOD__ 2 
#define __DECIMAL_BID_FORMAT__ 1 
#define __DECIMAL_DIG__ 21 
#define __ELF__ 1 
#define __FINITE_MATH_ONLY__ 0 
#define __FLOAT_WORD_ORDER__ __ORDER_LITTLE_ENDIAN__ 
#define __FLT_DECIMAL_DIG__ 9 
#define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F 
#define __FLT_DIG__ 6 
#define __FLT_EPSILON__ 1.19209289550781250000e-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__ 3.40282346638528859812e+38F 
#define __FLT_MAX_EXP__ 128 
#define __FLT_MIN_10_EXP__ (-37) 
#define __FLT_MIN__ 1.17549435082228750797e-38F 
#define __FLT_MIN_EXP__ (-125) 
#define __FLT_RADIX__ 2 
#define __FXSR__ 1 
#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 __GCC_HAVE_DWARF2_CFI_ASM 1 
#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 __GCC_IEC_559 2 
#define __GCC_IEC_559_COMPLEX 2 
#define __GNUC__ 5 
#define __GNUC_MINOR__ 2 
#define __GNUC_PATCHLEVEL__ 1 
#define __GNUC_STDC_INLINE__ 1 
#define __gnu_linux__ 1 
#define __GXX_ABI_VERSION 1009 
#define __has_include_next(STR) __has_include_next__(STR) 
#define __has_include(STR) __has_include__(STR) 
#define __ILP32__ 1 
#define _ILP32 1 
#define __INT16_C(c) c 
#define __INT16_MAX__ 0x7fff 
#define __INT16_TYPE__ short int 
#define __INT32_C(c) c 
#define __INT32_MAX__ 0x7fffffff 
#define __INT32_TYPE__ int 
#define __INT64_C(c) C## LL 
#define __INT64_MAX__ 0x7fffffffffffffffLL 
#define __INT64_TYPE__ long long int 
#define __INT8_C(c) c 
#define __INT8_MAX__ 0x7f 
#define __INT8_TYPE__ signed char 
#define __INT_FAST16_MAX__ 0x7fffffff 
#define __INT_FAST16_TYPE__ int 
#define __INT_FAST32_MAX__ 0x7fffffff 
#define __INT_FAST32_TYPE__ int 
#define __INT_FAST64_MAX__ 0x7fffffffffffffffLL 
#define __INT_FAST64_TYPE__ long long int 
#define __INT_FAST8_MAX__ 0x7f 
#define __INT_FAST8_TYPE__ signed char 
#define __INT_LEAST16_MAX__ 0x7fff 
#define __INT_LEAST16_TYPE__ short int 
#define __INT_LEAST32_MAX__ 0x7fffffff 
#define __INT_LEAST32_TYPE__ int 
#define __INT_LEAST64_MAX__ 0x7fffffffffffffffLL 
#define __INT_LEAST64_TYPE__ long long int 
#define __INT_LEAST8_MAX__ 0x7f 
#define __INT_LEAST8_TYPE__ signed char 
#define __INT_MAX__ 0x7fffffff 
#define __INTMAX_C(c) C## LL 
#define __INTMAX_MAX__ 0x7fffffffffffffffLL 
#define __INTMAX_TYPE__ long long int 
#define __INTPTR_MAX__ 0x7fffffff 
#define __INTPTR_TYPE__ int 
#define __k8 1 
#define __k8__ 1 
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L 
#define __LDBL_DIG__ 18 
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L 
#define __LDBL_HAS_DENORM__ 1 
#define __LDBL_HAS_INFINITY__ 1 
#define __LDBL_HAS_QUIET_NAN__ 1 
#define __LDBL_MANT_DIG__ 64 
#define __LDBL_MAX_10_EXP__ 4932 
#define __LDBL_MAX__ 1.18973149535723176502e+4932L 
#define __LDBL_MAX_EXP__ 16384 
#define __LDBL_MIN_10_EXP__ (-4931) 
#define __LDBL_MIN__ 3.36210314311209350626e-4932L 
#define __LDBL_MIN_EXP__ (-16381) 
#define __linux 1 
#define __linux__ 1 
#define linux 1 
#define __LONG_LONG_MAX__ 0x7fffffffffffffffLL 
#define __LONG_MAX__ 0x7fffffffL 
#define __MMX__ 1 
#define __NO_INLINE__ 1 
#define __ORDER_BIG_ENDIAN__ 4321 
#define __ORDER_LITTLE_ENDIAN__ 1234 
#define __ORDER_PDP_ENDIAN__ 3412 
#define __PRAGMA_REDEFINE_EXTNAME 1 
#define __PTRDIFF_MAX__ 0x7fffffff 
#define __PTRDIFF_TYPE__ int 
#define __REGISTER_PREFIX__ 
#define __SCHAR_MAX__ 0x7f 
#define __SHRT_MAX__ 0x7fff 
#define __SIG_ATOMIC_MAX__ 0x7fffffff 
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1) 
#define __SIG_ATOMIC_TYPE__ int 
#define __SIZE_MAX__ 0xffffffffU 
#define __SIZEOF_DOUBLE__ 8 
#define __SIZEOF_FLOAT128__ 16 
#define __SIZEOF_FLOAT__ 4 
#define __SIZEOF_FLOAT80__ 16 
#define __SIZEOF_INT128__ 16 
#define __SIZEOF_INT__ 4 
#define __SIZEOF_LONG__ 4 
#define __SIZEOF_LONG_DOUBLE__ 16 
#define __SIZEOF_LONG_LONG__ 8 
#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_TYPE__ unsigned int 
#define __SSE__ 1 
#define __SSE2__ 1 
#define __SSE2_MATH__ 1 
#define __SSE_MATH__ 1 
#define __STDC__ 1 
#define __STDC_HOSTED__ 1 
#define __STDC_IEC_559__ 1 
#define __STDC_IEC_559_COMPLEX__ 1 
#define __STDC_ISO_10646__ 201103L 
#define __STDC_NO_THREADS__ 1 
#define _STDC_PREDEF_H 1 
#define __STDC_UTF_16__ 1 
#define __STDC_UTF_32__ 1 
#define __STDC_VERSION__ 201112L 
#define __UINT16_C(c) c 
#define __UINT16_MAX__ 0xffff 
#define __UINT16_TYPE__ short unsigned int 
#define __UINT32_C(c) C## U 
#define __UINT32_MAX__ 0xffffffffU 
#define __UINT32_TYPE__ unsigned int 
#define __UINT64_C(c) C## ULL 
#define __UINT64_MAX__ 0xffffffffffffffffULL 
#define __UINT64_TYPE__ long long unsigned int 
#define __UINT8_C(c) c 
#define __UINT8_MAX__ 0xff 
#define __UINT8_TYPE__ unsigned char 
#define __UINT_FAST16_MAX__ 0xffffffffU 
#define __UINT_FAST16_TYPE__ unsigned int 
#define __UINT_FAST32_MAX__ 0xffffffffU 
#define __UINT_FAST32_TYPE__ unsigned int 
#define __UINT_FAST64_MAX__ 0xffffffffffffffffULL 
#define __UINT_FAST64_TYPE__ long long unsigned int 
#define __UINT_FAST8_MAX__ 0xff 
#define __UINT_FAST8_TYPE__ unsigned char 
#define __UINT_LEAST16_MAX__ 0xffff 
#define __UINT_LEAST16_TYPE__ short unsigned int 
#define __UINT_LEAST32_MAX__ 0xffffffffU 
#define __UINT_LEAST32_TYPE__ unsigned int 
#define __UINT_LEAST64_MAX__ 0xffffffffffffffffULL 
#define __UINT_LEAST64_TYPE__ long long unsigned int 
#define __UINT_LEAST8_MAX__ 0xff 
#define __UINT_LEAST8_TYPE__ unsigned char 
#define __UINTMAX_C(c) C## ULL 
#define __UINTMAX_MAX__ 0xffffffffffffffffULL 
#define __UINTMAX_TYPE__ long long unsigned int 
#define __UINTPTR_MAX__ 0xffffffffU 
#define __UINTPTR_TYPE__ unsigned int 
#define __unix 1 
#define __unix__ 1 
#define unix 1 
#define __USER_LABEL_PREFIX__ 
#define __VERSION__ "5.2.1 20150911" 
#define __WCHAR_MAX__ 0x7fffffffL 
#define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1) 
#define __WCHAR_TYPE__ long int 
#define __WINT_MAX__ 0xffffffffU 
#define __WINT_MIN__ 0U 
#define __WINT_TYPE__ unsigned int 
#define __x86_64 1 
#define __x86_64__ 1 

Answer 1

似乎沒有成爲一個預定義宏明確指定的X32環境。比較cpp -dM和cpp -dM -mx32的輸出，僅針對x32定義符號_ILP32和__ILP32__，並且僅針對不具有x32的x86_64定義_LP64和__LP64__。其他許多預定義的宏對於這兩種環境具有不同的值。

我認爲在編譯時檢測x32最直接的方法是檢查__x86_64__和SIZE_MAX宏。前者由gcc預定義（或不​​），後者在<stdint.h>中定義。

下面的程序演示了這一點。它適用於x86_64系統上的gcc -m64,gcc -m32和gcc -mx32，以及非x86_64系統（SPARC）上的gcc。

#include <stdio.h> 
#include <stdint.h> 
int main(void) { 
#ifdef __x86_64__ 
    #if SIZE_MAX == 0xFFFFFFFF 
     puts("This is x32"); 
    #else 
     puts("This is x86_64 but not x32"); 
    #endif 
#else 
    puts("This is not x64_64"); 
#endif 
}