Commit 5d5cc0d0 authored by Johann's avatar Johann

Check for bswap* builtins before using

Canonical builtin checks for clang are to use
__has_builtin. Much less fragile than version checks.

https://code.google.com/p/webm/issues/detail?id=1082

Change-Id: I8151fb75899acdf1a935c23aad9441da99a9abcd
parent ec623a0b
......@@ -25,14 +25,10 @@
# define LOCAL_GCC_PREREQ(maj, min) 0
#endif
#ifdef __clang__
# define LOCAL_CLANG_VERSION ((__clang_major__ << 8) | __clang_minor__)
# define LOCAL_CLANG_PREREQ(maj, min) \
(LOCAL_CLANG_VERSION >= (((maj) << 8) | (min)))
#else
# define LOCAL_CLANG_VERSION 0
# define LOCAL_CLANG_PREREQ(maj, min) 0
#endif // __clang__
// handle clang compatibility
#ifndef __has_builtin
# define __has_builtin(x) 0
#endif
// some endian fix (e.g.: mips-gcc doesn't define __BIG_ENDIAN__)
#if !defined(WORDS_BIGENDIAN) && \
......@@ -53,14 +49,16 @@
#define HToBE32(X) BSwap32(X)
#endif
// clang-3.3 and gcc-4.3 have builtin functions for swap32/swap64
#if LOCAL_GCC_PREREQ(4, 3) || LOCAL_CLANG_PREREQ(3, 3)
#if LOCAL_GCC_PREREQ(4, 8) || __has_builtin(__builtin_bswap16)
#define HAVE_BUILTIN_BSWAP16
#endif
#if LOCAL_GCC_PREREQ(4, 3) || __has_builtin(__builtin_bswap32)
#define HAVE_BUILTIN_BSWAP32
#define HAVE_BUILTIN_BSWAP64
#endif
// clang-3.3 and gcc-4.8 have a builtin function for swap16
#if LOCAL_GCC_PREREQ(4, 8) || LOCAL_CLANG_PREREQ(3, 3)
#define HAVE_BUILTIN_BSWAP16
#if LOCAL_GCC_PREREQ(4, 3) || __has_builtin(__builtin_bswap64)
#define HAVE_BUILTIN_BSWAP64
#endif
#if HAVE_MIPS32 && defined(__mips__) && !defined(__mips64) && \
......
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