Compiler.h revision ee7f73b009784b73074eeb80a284afe30cf2a77a 
1//===-- llvm/Support/Compiler.h - Compiler abstraction support --*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
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.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_SUPPORT_COMPILER_H
16#define LLVM_SUPPORT_COMPILER_H
17
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")))
22#else
23#define VISIBILITY_HIDDEN
24#endif
25
26#if (__GNUC__ >= 4)
27#define ATTRIBUTE_USED __attribute__((__used__))
28#else
29#define ATTRIBUTE_USED
30#endif
31
32// C++ doesn't support 'extern template' of template specializations.  GCC does,
33// but requires __extension__ before it.  In the header, use this:
34//   EXTERN_TEMPLATE_INSTANTIATION(class foo<bar>);
35// in the .cpp file, use this:
36//   TEMPLATE_INSTANTIATION(class foo<bar>);
37#ifdef __GNUC__
38#define EXTERN_TEMPLATE_INSTANTIATION(X) __extension__ extern template X
39#define TEMPLATE_INSTANTIATION(X) template X
40#else
41#define EXTERN_TEMPLATE_INSTANTIATION(X)
42#define TEMPLATE_INSTANTIATION(X)
43#endif
44
45// DISABLE_INLINE - On compilers where we have a directive to do so, mark a
46// method "not for inlining".
47#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
48#define DISABLE_INLINE __attribute__((noinline))
49#else
50#define DISABLE_INLINE
51#endif
52
53#endif
54