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
75