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| -rw-r--r-- | include/qemu/compiler.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index a309f90..b037442 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -22,6 +22,36 @@ #define QEMU_EXTERN_C extern #endif +/* + * Tricky points: + * - Use __builtin_choose_expr to avoid type promotion from ?:, + * - Invalid sizes result in a compile time error stemming from + * the fact that abort has no parameters. + * - It's easier to use the endian-specific unaligned load/store + * functions than host-endian unaligned load/store plus tswapN. + * - The pragmas are necessary only to silence a clang false-positive + * warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 . + * - We have to disable -Wpragmas warnings to avoid a complaint about + * an unknown warning type from older compilers that don't know about + * -Waddress-of-packed-member. + * - gcc has bugs in its _Pragma() support in some versions, eg + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only + * include the warning-suppression pragmas for clang + */ +#ifdef __clang__ +#define PRAGMA_DISABLE_PACKED_WARNING \ + _Pragma("GCC diagnostic push"); \ + _Pragma("GCC diagnostic ignored \"-Wpragmas\""); \ + _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"") + +#define PRAGMA_REENABLE_PACKED_WARNING \ + _Pragma("GCC diagnostic pop") + +#else +#define PRAGMA_DISABLE_PACKED_WARNING +#define PRAGMA_REENABLE_PACKED_WARNING +#endif + #if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__)) # define QEMU_PACKED __attribute__((gcc_struct, packed)) #else |