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llvm-mirror/include/llvm/Support/Compiler.h
Chris Lattner acb553060b don't use always_inline with gcc 3.4, it has some unimplemented features
and is too old to really care about the performance of the generated 
compiler.

llvm-svn: 97662
2010-03-03 20:47:12 +00:00

100 lines
3.0 KiB
C++

//===-- llvm/Support/Compiler.h - Compiler abstraction support --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines several macros, based on the current compiler. This allows
// use of compiler-specific features in a way that remains portable.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_COMPILER_H
#define LLVM_SUPPORT_COMPILER_H
// The VISIBILITY_HIDDEN macro, used for marking classes with the GCC-specific
// visibility("hidden") attribute.
#if (__GNUC__ >= 4) && !defined(__MINGW32__) && !defined(__CYGWIN__)
#define VISIBILITY_HIDDEN __attribute__ ((visibility("hidden")))
#else
#define VISIBILITY_HIDDEN
#endif
#if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
#define ATTRIBUTE_USED __attribute__((__used__))
#else
#define ATTRIBUTE_USED
#endif
#if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
#define ATTRIBUTE_UNUSED __attribute__((__unused__))
#else
#define ATTRIBUTE_UNUSED
#endif
#ifdef __GNUC__ // aka 'ATTRIBUTE_CONST' but following LLVM Conventions.
#define ATTRIBUTE_READNONE __attribute__((__const__))
#else
#define ATTRIBUTE_READNONE
#endif
#ifdef __GNUC__ // aka 'ATTRIBUTE_PURE' but following LLVM Conventions.
#define ATTRIBUTE_READONLY __attribute__((__pure__))
#else
#define ATTRIBUTE_READONLY
#endif
#if (__GNUC__ >= 4)
#define BUILTIN_EXPECT(EXPR, VALUE) __builtin_expect((EXPR), (VALUE))
#else
#define BUILTIN_EXPECT(EXPR, VALUE) (EXPR)
#endif
// C++ doesn't support 'extern template' of template specializations. GCC does,
// but requires __extension__ before it. In the header, use this:
// EXTERN_TEMPLATE_INSTANTIATION(class foo<bar>);
// in the .cpp file, use this:
// TEMPLATE_INSTANTIATION(class foo<bar>);
#ifdef __GNUC__
#define EXTERN_TEMPLATE_INSTANTIATION(X) __extension__ extern template X
#define TEMPLATE_INSTANTIATION(X) template X
#else
#define EXTERN_TEMPLATE_INSTANTIATION(X)
#define TEMPLATE_INSTANTIATION(X)
#endif
// DISABLE_INLINE - On compilers where we have a directive to do so, mark a
// method "not for inlining".
#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
#define DISABLE_INLINE __attribute__((noinline))
#elif defined(_MSC_VER)
#define DISABLE_INLINE __declspec(noinline)
#else
#define DISABLE_INLINE
#endif
// ALWAYS_INLINE - On compilers where we have a directive to do so, mark a
// method "always inline" because it is performance sensitive.
// GCC 3.4 supported this but is buggy in various cases and produces
// unimplemented errors, just use it in GCC 4.0 and later.
#if __GNUC__ > 3
#define ALWAYS_INLINE __attribute__((always_inline))
#else
// TODO: No idea how to do this with MSVC.
#define ALWAYS_INLINE
#endif
#ifdef __GNUC__
#define NORETURN __attribute__((noreturn))
#elif defined(_MSC_VER)
#define NORETURN __declspec(noreturn)
#else
#define NORETURN
#endif
#endif