From 4c0803d16504079f58c85f88f376c0d3842004c5 Mon Sep 17 00:00:00 2001 From: Elliott Hughes Date: Fri, 8 Sep 2017 16:52:59 -0700 Subject: [PATCH] Cast __builtin_swap64 to uint64_t. strace 4.19 causes clang to emit a questionable warning: external/strace/nlattr.c:254:35: error: format specifies type 'unsigned long' but the argument has type 'unsigned long long' [-Werror,-Wformat] tprintf("htobe64(%" PRIu64 ")", be64toh(num)); ~~~ ^~~~~~~~~~~~ bionic/libc/include/sys/endian.h:100:20: note: expanded from macro 'be64toh' #define be64toh(x) htobe64(x) ^~~~~~~~~~ bionic/libc/include/sys/endian.h:80:17: note: expanded from macro 'htobe64' #define htobe64 __swap64 ^ bionic/libc/include/sys/endian.h:48:18: note: expanded from macro '__swap64' #define __swap64 __builtin_bswap64 ^ What's happened here is: * be64toh is __builtin_bswap64 * PRIu64 is "lu" * __builtin_bswap64 is internally declared a "ULLiULLi" All of which leads to the `unsigned long` != `unsigned long long` complaint. It seems like __builtin_bswap64 should be ULiULi on 64-bit architectures, where `long` rather than `long long` is the natural way to refer to 64-bit types, as evidenced by the "lu" for PRIu64. As long as clang behaves like this, though, we can work around it with a cast. Also clean up the other casts in the file, be more consistent about whether these function-like macros are defined with an argument, and remove an incorrect comment. Bug: http://b/65495954 Test: ran tests, built strace 4.19 without warnings Change-Id: I8e06d4bf71e95d62f556eab8661033e04d487e0d --- libc/include/sys/endian.h | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/libc/include/sys/endian.h b/libc/include/sys/endian.h index 799a6f285..9155b4cb4 100644 --- a/libc/include/sys/endian.h +++ b/libc/include/sys/endian.h @@ -45,7 +45,7 @@ #define __swap16 __builtin_bswap16 #define __swap32 __builtin_bswap32 -#define __swap64 __builtin_bswap64 +#define __swap64(x) __BIONIC_CAST(static_cast,uint64_t,__builtin_bswap64(x)) /* glibc compatibility. */ __BEGIN_DECLS @@ -70,17 +70,17 @@ __END_DECLS #define PDP_ENDIAN _PDP_ENDIAN #define BYTE_ORDER _BYTE_ORDER -#define NTOHL(x) (x) = ntohl((u_int32_t)(x)) -#define NTOHS(x) (x) = ntohs((u_int16_t)(x)) -#define HTONL(x) (x) = htonl((u_int32_t)(x)) -#define HTONS(x) (x) = htons((u_int16_t)(x)) +#define NTOHL(x) (x) = ntohl(__BIONIC_CAST(static_cast,u_int32_t,(x))) +#define NTOHS(x) (x) = ntohs(__BIONIC_CAST(static_cast,u_int16_t,(x))) +#define HTONL(x) (x) = htonl(__BIONIC_CAST(static_cast,u_int32_t,(x))) +#define HTONS(x) (x) = htons(__BIONIC_CAST(static_cast,u_int16_t,(x))) -#define htobe16 __swap16 -#define htobe32 __swap32 -#define htobe64 __swap64 -#define betoh16 __swap16 -#define betoh32 __swap32 -#define betoh64 __swap64 +#define htobe16(x) __swap16(x) +#define htobe32(x) __swap32(x) +#define htobe64(x) __swap64(x) +#define betoh16(x) __swap16(x) +#define betoh32(x) __swap32(x) +#define betoh64(x) __swap64(x) #define htole16(x) (x) #define htole32(x) (x) @@ -101,6 +101,7 @@ __END_DECLS #define le16toh(x) htole16(x) #define le32toh(x) htole32(x) #define le64toh(x) htole64(x) -#endif /* __USE_BSD */ + +#endif #endif