compiler-rt/lib/orc/compiler.h

   1 //===--------- compiler.h - Compiler abstraction support --------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of the ORC runtime support library.
  10 //
  11 // Most functionality in this file was swiped from llvm/Support/Compiler.h.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef ORC_RT_COMPILER_H
  16 #define ORC_RT_COMPILER_H
  17
  18 #if defined(_WIN32)
  19 #define ORC_RT_INTERFACE extern "C"
  20 #define ORC_RT_HIDDEN
  21 #define ORC_RT_IMPORT extern "C" __declspec(dllimport)
  22 #else
  23 #define ORC_RT_INTERFACE extern "C" __attribute__((visibility("default")))
  24 #define ORC_RT_HIDDEN __attribute__((visibility("hidden")))
  25 #define ORC_RT_IMPORT extern "C"
  26 #endif
  27
  28 #ifndef __has_builtin
  29 # define __has_builtin(x) 0
  30 #endif
  31
  32 // Only use __has_cpp_attribute in C++ mode. GCC defines __has_cpp_attribute in
  33 // C mode, but the :: in __has_cpp_attribute(scoped::attribute) is invalid.
  34 #ifndef ORC_RT_HAS_CPP_ATTRIBUTE
  35 #if defined(__cplusplus) && defined(__has_cpp_attribute)
  36 #define ORC_RT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
  37 #else
  38 #define ORC_RT_HAS_CPP_ATTRIBUTE(x) 0
  39 #endif
  40 #endif
  41
  42 // Use the 'nodiscard' attribute in C++17 or newer mode.
  43 #if defined(__cplusplus) && __cplusplus > 201402L &&                           \
  44     ORC_RT_HAS_CPP_ATTRIBUTE(nodiscard)
  45 #define ORC_RT_NODISCARD [[nodiscard]]
  46 #elif ORC_RT_HAS_CPP_ATTRIBUTE(clang::warn_unused_result)
  47 #define ORC_RT_NODISCARD [[clang::warn_unused_result]]
  48 // Clang in C++14 mode claims that it has the 'nodiscard' attribute, but also
  49 // warns in the pedantic mode that 'nodiscard' is a C++17 extension (PR33518).
  50 // Use the 'nodiscard' attribute in C++14 mode only with GCC.
  51 // TODO: remove this workaround when PR33518 is resolved.
  52 #elif defined(__GNUC__) && ORC_RT_HAS_CPP_ATTRIBUTE(nodiscard)
  53 #define ORC_RT_NODISCARD [[nodiscard]]
  54 #else
  55 #define ORC_RT_NODISCARD
  56 #endif
  57
  58 #if __has_builtin(__builtin_expect)
  59 #define ORC_RT_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
  60 #define ORC_RT_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
  61 #else
  62 #define ORC_RT_LIKELY(EXPR) (EXPR)
  63 #define ORC_RT_UNLIKELY(EXPR) (EXPR)
  64 #endif
  65
  66 #if defined(__APPLE__)
  67 #define ORC_RT_WEAK_IMPORT __attribute__((weak_import))
  68 #elif defined(_WIN32)
  69 #define ORC_RT_WEAK_IMPORT
  70 #else
  71 #define ORC_RT_WEAK_IMPORT __attribute__((weak))
  72 #endif
  73
  74 #endif // ORC_RT_COMPILER_H