| //===-- Common internal contructs -------------------------------*- C++ -*-===// |
| // |
| // 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_SUPPORT_COMMON_H |
| #define LLVM_LIBC_SUPPORT_COMMON_H |
| |
| #define LIBC_INLINE_ASM __asm__ __volatile__ |
| |
| #define likely(x) __builtin_expect(!!(x), 1) |
| #define unlikely(x) __builtin_expect(x, 0) |
| #define UNUSED __attribute__((unused)) |
| |
| #ifndef LLVM_LIBC_FUNCTION_ATTR |
| #define LLVM_LIBC_FUNCTION_ATTR |
| #endif |
| |
| #ifdef LLVM_LIBC_PUBLIC_PACKAGING |
| #define LLVM_LIBC_FUNCTION(type, name, arglist) \ |
| LLVM_LIBC_FUNCTION_ATTR decltype(__llvm_libc::name) \ |
| __##name##_impl__ __asm__(#name); \ |
| decltype(__llvm_libc::name) name [[gnu::alias(#name)]]; \ |
| type __##name##_impl__ arglist |
| #else |
| #define LLVM_LIBC_FUNCTION(type, name, arglist) type name arglist |
| #endif |
| |
| namespace __llvm_libc { |
| namespace internal { |
| constexpr bool same_string(char const *lhs, char const *rhs) { |
| for (; *lhs || *rhs; ++lhs, ++rhs) |
| if (*lhs != *rhs) |
| return false; |
| return true; |
| } |
| } // namespace internal |
| } // namespace __llvm_libc |
| |
| // LLVM_LIBC_IS_DEFINED checks whether a particular macro is defined. |
| // Usage: constexpr bool kUseAvx = LLVM_LIBC_IS_DEFINED(__AVX__); |
| // |
| // This works by comparing the stringified version of the macro with and without |
| // evaluation. If FOO is not undefined both stringifications yield "FOO". If FOO |
| // is defined, one stringification yields "FOO" while the other yields its |
| // stringified value "1". |
| #define LLVM_LIBC_IS_DEFINED(macro) \ |
| !__llvm_libc::internal::same_string( \ |
| LLVM_LIBC_IS_DEFINED__EVAL_AND_STRINGIZE(macro), #macro) |
| #define LLVM_LIBC_IS_DEFINED__EVAL_AND_STRINGIZE(s) #s |
| |
| #endif // LLVM_LIBC_SUPPORT_COMMON_H |