Switch crypto/bn back to _umul128 on Windows clang.
Upstream (impressively quickly) fixed the missing intrinsic. Switch Windows
clang back to building the same code as MSVC. Also include the intrin.h header
rather than forward-declare the intrinsic. clang only works if the header is
explicitly included. Chromium forcibly includes it to work around these kinds
of issues, but we shouldn't rely on it.
BUG=crbug.com/438382
Change-Id: I0ff6d48e1a3aa455cff99f8dc4c407e88b84d446
Reviewed-on: https://boringssl-review.googlesource.com/2461
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/bn/internal.h b/crypto/bn/internal.h
index 573ddd7..e94f5ad 100644
--- a/crypto/bn/internal.h
+++ b/crypto/bn/internal.h
@@ -127,6 +127,11 @@
#include <inttypes.h>
+#if defined(OPENSSL_X86_64) && defined(_MSC_VER) && _MSC_VER >= 1400
+#include <intrin.h>
+#pragma intrinsic(__umulh, _umul128)
+#endif
+
#if defined(__cplusplus)
extern "C" {
#endif
@@ -239,8 +244,7 @@
}
#if !defined(OPENSSL_NO_ASM) && defined(OPENSSL_X86_64)
-/* Windows clang lacks _umul128, but inline asm works. */
-# if (defined(__GNUC__) && __GNUC__>=2) || defined(__clang__)
+# if defined(__GNUC__) && __GNUC__ >= 2
# define BN_UMULT_HIGH(a,b) ({ \
register BN_ULONG ret,discard; \
__asm__ ("mulq %3" \
@@ -253,13 +257,9 @@
: "=a"(low),"=d"(high) \
: "a"(a),"g"(b) \
: "cc");
-# elif defined(_MSC_VER) && _MSC_VER>=1400
- unsigned __int64 __umulh (unsigned __int64 a,unsigned __int64 b);
- unsigned __int64 _umul128 (unsigned __int64 a,unsigned __int64 b,
- unsigned __int64 *h);
-# pragma intrinsic(__umulh,_umul128)
-# define BN_UMULT_HIGH(a,b) __umulh((a),(b))
-# define BN_UMULT_LOHI(low,high,a,b) ((low)=_umul128((a),(b),&(high)))
+# elif defined(_MSC_VER) && _MSC_VER >= 1400
+# define BN_UMULT_HIGH(a, b) __umulh((a), (b))
+# define BN_UMULT_LOHI(low, high, a, b) ((low) = _umul128((a), (b), &(high)))
# endif
#elif !defined(OPENSSL_NO_ASM) && defined(OPENSSL_AARCH64)
# if defined(__GNUC__) && __GNUC__>=2
