1 //===-- llvm/Support/Compiler.h - Compiler abstraction support --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines several macros, based on the current compiler. This allows
11 // use of compiler-specific features in a way that remains portable.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SUPPORT_COMPILER_H
16 #define LLVM_SUPPORT_COMPILER_H
18 // The VISIBILITY_HIDDEN macro, used for marking classes with the GCC-specific
19 // visibility("hidden") attribute.
20 #if (__GNUC__ >= 4) && !defined(__MINGW32__) && !defined(__CYGWIN__)
21 #define VISIBILITY_HIDDEN __attribute__ ((visibility("hidden")))
23 #define VISIBILITY_HIDDEN
26 #if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
27 #define ATTRIBUTE_USED __attribute__((__used__))
29 #define ATTRIBUTE_USED
33 #define BUILTIN_EXPECT(EXPR, VALUE) __builtin_expect((EXPR), (VALUE))
35 #define BUILTIN_EXPECT(EXPR, VALUE) (EXPR)
38 // C++ doesn't support 'extern template' of template specializations. GCC does,
39 // but requires __extension__ before it. In the header, use this:
40 // EXTERN_TEMPLATE_INSTANTIATION(class foo<bar>);
41 // in the .cpp file, use this:
42 // TEMPLATE_INSTANTIATION(class foo<bar>);
44 #define EXTERN_TEMPLATE_INSTANTIATION(X) __extension__ extern template X
45 #define TEMPLATE_INSTANTIATION(X) template X
47 #define EXTERN_TEMPLATE_INSTANTIATION(X)
48 #define TEMPLATE_INSTANTIATION(X)
51 // DISABLE_INLINE - On compilers where we have a directive to do so, mark a
52 // method "not for inlining".
53 #if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
54 #define DISABLE_INLINE __attribute__((noinline))
56 #define DISABLE_INLINE
60 #define NORETURN __attribute__((noreturn))