1 files changed, 98 insertions, 0 deletions
diff --git a/libc/include/__llvm-libc-common.h b/libc/include/__llvm-libc-common.h
new file mode 100644
index 000000000000..c6fd33a55532
--- /dev/null
+++ b/libc/include/__llvm-libc-common.h
@@ -0,0 +1,98 @@
+//===-- Common definitions for LLVM-libc public header files --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LLVM_LIBC_COMMON_H
+#define _LLVM_LIBC_COMMON_H
+
+#define __LLVM_LIBC__ 1
+
+#ifdef __cplusplus
+
+#undef __BEGIN_C_DECLS
+#define __BEGIN_C_DECLS extern "C" {
+
+#undef __END_C_DECLS
+#define __END_C_DECLS }
+
+// Standard C++ doesn't have C99 restrict but GNU C++ has it with __ spelling.
+#undef __restrict
+#ifndef __GNUC__
+#define __restrict
+#endif
+
+#undef _Noreturn
+#define _Noreturn [[noreturn]]
+
+#undef _Alignas
+#define _Alignas alignas
+
+#undef _Static_assert
+#define _Static_assert static_assert
+
+#undef _Alignof
+#define _Alignof alignof
+
+#undef _Thread_local
+#define _Thread_local thread_local
+
+#undef __NOEXCEPT
+#if __cplusplus >= 201103L
+#define __NOEXCEPT noexcept
+#else
+#define __NOEXCEPT throw()
+#endif
+
+// This macro serves as a generic cast implementation for use in both C and C++,
+// similar to `__BIONIC_CAST` in Android.
+#undef __LLVM_LIBC_CAST
+#define __LLVM_LIBC_CAST(cast, type, value) (cast<type>(value))
+
+#else // not __cplusplus
+
+#undef __BEGIN_C_DECLS
+#define __BEGIN_C_DECLS
+
+#undef __END_C_DECLS
+#define __END_C_DECLS
+
+#undef __restrict
+#if __STDC_VERSION__ >= 199901L
+// C99 and above support the restrict keyword.
+#define __restrict restrict
+#elif !defined(__GNUC__)
+// GNU-compatible compilers accept the __ spelling in all modes.
+// Otherwise, omit the qualifier for pure C89 compatibility.
+#define __restrict
+#endif
+
+#undef _Noreturn
+#if __STDC_VERSION__ >= 201112L
+// In C11 and later, _Noreturn is a keyword.
+#elif defined(__GNUC__)
+// GNU-compatible compilers have an equivalent attribute.
+#define _Noreturn __attribute__((__noreturn__))
+#else
+#define _Noreturn
+#endif
+
+#undef __NOEXCEPT
+#ifdef __GNUC__
+#define __NOEXCEPT __attribute__((__nothrow__))
+#else
+#define __NOEXCEPT
+#endif
+
+#undef _Returns_twice
+#define _Returns_twice __attribute__((returns_twice))
+
+#undef __LLVM_LIBC_CAST
+#define __LLVM_LIBC_CAST(cast, type, value) ((type)(value))
+
+#endif // __cplusplus
+
+#endif // _LLVM_LIBC_COMMON_H