xref: /external/v8/src/base/compiler-specific.h

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_BASE_COMPILER_SPECIFIC_H_
#define V8_BASE_COMPILER_SPECIFIC_H_

#include "include/v8config.h"

// Annotate a typedef or function indicating it's ok if it's not used.
// Use like:
//   typedef Foo Bar ALLOW_UNUSED_TYPE;
#if V8_HAS_ATTRIBUTE_UNUSED
#define ALLOW_UNUSED_TYPE __attribute__((unused))
#else
#define ALLOW_UNUSED_TYPE
#endif


// Annotate a function indicating the caller must examine the return value.
// Use like:
//   int foo() WARN_UNUSED_RESULT;
#if V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
#define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
#else
#define WARN_UNUSED_RESULT /* NOT SUPPORTED */
#endif

// Tell the compiler a function is using a printf-style format string.
// |format_param| is the one-based index of the format string parameter;
// |dots_param| is the one-based index of the "..." parameter.
// For v*printf functions (which take a va_list), pass 0 for dots_param.
// (This is undocumented but matches what the system C headers do.)
#if defined(__GNUC__)
#define PRINTF_FORMAT(format_param, dots_param) \
  __attribute__((format(printf, format_param, dots_param)))
#else
#define PRINTF_FORMAT(format_param, dots_param)
#endif

// The C++ standard requires that static const members have an out-of-class
// definition (in a single compilation unit), but MSVC chokes on this (when
// language extensions, which are required, are enabled). (You're only likely to
// notice the need for a definition if you take the address of the member or,
// more commonly, pass it to a function that takes it as a reference argument --
// probably an STL function.) This macro makes MSVC do the right thing. See
// http://msdn.microsoft.com/en-us/library/34h23df8(v=vs.100).aspx for more
// information. Use like:
//
// In .h file:
//   struct Foo {
//     static const int kBar = 5;
//   };
//
// In .cc file:
//   STATIC_CONST_MEMBER_DEFINITION const int Foo::kBar;
#if V8_HAS_DECLSPEC_SELECTANY
#define STATIC_CONST_MEMBER_DEFINITION __declspec(selectany)
#else
#define STATIC_CONST_MEMBER_DEFINITION
#endif

#endif  // V8_BASE_COMPILER_SPECIFIC_H_