Define __ARM_ARCH with older compilers

This is needed for GCC 4.7 and earlier, as well as Visual Studio 2022 version 17.9 and earlier.

src/arm/32/util.S

@@ -31,6 +31,7 @@
 
 #include "config.h"
 #include "src/arm/asm.S"
+#include "src/arm/arm-arch.h"
 
 .macro v4bx rd
 #if __ARM_ARCH >= 5 || defined(__ARM_ARCH_4T__)

src/arm/arm-arch.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright © 2024, VideoLAN and dav1d authors
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef ARM_ARM_ARCH_H
+#define ARM_ARM_ARCH_H
+
+/* Compatibility header to define __ARM_ARCH with older compilers */
+#ifndef __ARM_ARCH
+
+#ifdef _M_ARM
+#define __ARM_ARCH _M_ARM
+
+#elif defined(__ARM_ARCH_8A__) || defined(_M_ARM64)
+#define __ARM_ARCH 8
+
+#elif defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || \
+      defined(__ARM_ARCH_7EM__) || defined(__ARM_ARCH_7R__) || \
+      defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__)
+#define __ARM_ARCH 7
+
+#elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || \
+      defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__) || \
+      defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__)
+#define __ARM_ARCH 6
+
+#elif defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_5T__) || \
+      defined(__ARM_ARCH_5E__) || defined(__ARM_ARCH_5TE__)
+#define __ARM_ARCH 5
+
+#elif defined(__ARM_ARCH_4__) || defined(__ARM_ARCH_4T__)
+#define __ARM_ARCH 4
+
+#elif defined(__ARM_ARCH_3__) || defined(__ARM_ARCH_3M__)
+#define __ARM_ARCH 3
+
+#elif defined(__ARM_ARCH_2__)
+#define __ARM_ARCH 2
+
+#else
+#error Unknown ARM architecture version
+#endif
+
+#endif /* !__ARM_ARCH */
+
+#endif /* ARM_ARM_ARCH_H */

tests/checkasm/checkasm.h

@@ -68,6 +68,10 @@ typedef sigjmp_buf checkasm_context;
 #include "include/common/bitdepth.h"
 #include "include/common/intops.h"
 
+#if ARCH_ARM
+#include "src/arm/arm-arch.h"
+#endif
+
 int xor128_rand(void);
 #define rnd xor128_rand