1 files changed, 60 insertions, 1 deletions
diff --git a/lib/builtins/int_lib.h b/lib/builtins/int_lib.h
index bca5d81d4414..e66cda3fffb4 100644
--- a/lib/builtins/int_lib.h
+++ b/lib/builtins/int_lib.h
@@ -20,6 +20,13 @@
 /* Assumption: Right shift of signed negative is arithmetic shift. */
 /* Assumption: Endianness is little or big (not mixed). */
 
+#if defined(__ELF__)
+#define FNALIAS(alias_name, original_name) \
+  void alias_name() __attribute__((alias(#original_name)))
+#else
+#define FNALIAS(alias, name) _Pragma("GCC error(\"alias unsupported on this file format\")")
+#endif
+
 /* ABI macro definitions */
 
 #if __ARM_EABI__
@@ -28,13 +35,25 @@
 # define COMPILER_RT_ABI __attribute__((pcs("aapcs")))
 #else
 # define ARM_EABI_FNALIAS(aeabi_name, name)
-# if defined(__arm__) && defined(_WIN32)
+# if defined(__arm__) && defined(_WIN32) && (!defined(_MSC_VER) || defined(__clang__))
 #   define COMPILER_RT_ABI __attribute__((pcs("aapcs")))
 # else
 #   define COMPILER_RT_ABI
 # endif
 #endif
 
+#ifdef _MSC_VER
+#define ALWAYS_INLINE __forceinline
+#define NOINLINE __declspec(noinline)
+#define NORETURN __declspec(noreturn)
+#define UNUSED
+#else
+#define ALWAYS_INLINE __attribute__((always_inline))
+#define NOINLINE __attribute__((noinline))
+#define NORETURN __attribute__((noreturn))
+#define UNUSED __attribute__((unused))
+#endif
+
 #if defined(__NetBSD__) && (defined(_KERNEL) || defined(_STANDALONE))
 /*
  * Kernel and boot environment can't use normal headers,
@@ -71,4 +90,44 @@ COMPILER_RT_ABI si_int __clzti2(ti_int a);
 COMPILER_RT_ABI tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem);
 #endif
 
+/* Definitions for builtins unavailable on MSVC */
+#if defined(_MSC_VER) && !defined(__clang__)
+#include <intrin.h>
+
+uint32_t __inline __builtin_ctz(uint32_t value) {
+  uint32_t trailing_zero = 0;
+  if (_BitScanForward(&trailing_zero, value))
+    return trailing_zero;
+  return 32;
+}
+
+uint32_t __inline __builtin_clz(uint32_t value) {
+  uint32_t leading_zero = 0;
+  if (_BitScanReverse(&leading_zero, value))
+    return 31 - leading_zero;
+  return 32;
+}
+
+#if defined(_M_ARM) || defined(_M_X64)
+uint32_t __inline __builtin_clzll(uint64_t value) {
+  uint32_t leading_zero = 0;
+  if (_BitScanReverse64(&leading_zero, value))
+    return 63 - leading_zero;
+  return 64;
+}
+#else
+uint32_t __inline __builtin_clzll(uint64_t value) {
+  if (value == 0)
+    return 64;
+  uint32_t msh = (uint32_t)(value >> 32);
+  uint32_t lsh = (uint32_t)(value & 0xFFFFFFFF);
+  if (msh != 0)
+    return __builtin_clz(msh);
+  return 32 + __builtin_clz(lsh);
+}
+#endif
+
+#define __builtin_clzl __builtin_clzll
+#endif /* defined(_MSC_VER) && !defined(__clang__) */
+
 #endif /* INT_LIB_H */