1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_COMPILER_SPECIFIC_H_
6#define BASE_COMPILER_SPECIFIC_H_
7#pragma once
8
9#include "build/build_config.h"
10
11#if defined(COMPILER_MSVC)
12
13// Macros for suppressing and disabling warnings on MSVC.
14//
15// Warning numbers are enumerated at:
16// http://msdn.microsoft.com/en-us/library/8x5x43k7(VS.80).aspx
17//
18// The warning pragma:
19// http://msdn.microsoft.com/en-us/library/2c8f766e(VS.80).aspx
20//
21// Using __pragma instead of #pragma inside macros:
22// http://msdn.microsoft.com/en-us/library/d9x1s805.aspx
23
24// MSVC_SUPPRESS_WARNING disables warning |n| for the remainder of the line and
25// for the next line of the source file.
26#define MSVC_SUPPRESS_WARNING(n) __pragma(warning(suppress:n))
27
28// MSVC_PUSH_DISABLE_WARNING pushes |n| onto a stack of warnings to be disabled.
29// The warning remains disabled until popped by MSVC_POP_WARNING.
30#define MSVC_PUSH_DISABLE_WARNING(n) __pragma(warning(push)) \
31                                     __pragma(warning(disable:n))
32
33// MSVC_PUSH_WARNING_LEVEL pushes |n| as the global warning level.  The level
34// remains in effect until popped by MSVC_POP_WARNING().  Use 0 to disable all
35// warnings.
36#define MSVC_PUSH_WARNING_LEVEL(n) __pragma(warning(push, n))
37
38// Pop effects of innermost MSVC_PUSH_* macro.
39#define MSVC_POP_WARNING() __pragma(warning(pop))
40
41#define MSVC_DISABLE_OPTIMIZE() __pragma(optimize("", off))
42#define MSVC_ENABLE_OPTIMIZE() __pragma(optimize("", on))
43
44// Allows |this| to be passed as an argument in constructor initializer lists.
45// This uses push/pop instead of the seemingly simpler suppress feature to avoid
46// having the warning be disabled for more than just |code|.
47//
48// Example usage:
49// Foo::Foo() : x(NULL), ALLOW_THIS_IN_INITIALIZER_LIST(y(this)), z(3) {}
50//
51// Compiler warning C4355: 'this': used in base member initializer list:
52// http://msdn.microsoft.com/en-us/library/3c594ae3(VS.80).aspx
53#define ALLOW_THIS_IN_INITIALIZER_LIST(code) MSVC_PUSH_DISABLE_WARNING(4355) \
54                                             code \
55                                             MSVC_POP_WARNING()
56
57#else  // Not MSVC
58
59#define MSVC_SUPPRESS_WARNING(n)
60#define MSVC_PUSH_DISABLE_WARNING(n)
61#define MSVC_PUSH_WARNING_LEVEL(n)
62#define MSVC_POP_WARNING()
63#define MSVC_DISABLE_OPTIMIZE()
64#define MSVC_ENABLE_OPTIMIZE()
65#define ALLOW_THIS_IN_INITIALIZER_LIST(code) code
66
67#endif  // COMPILER_MSVC
68
69
70// Annotate a variable indicating it's ok if the variable is not used.
71// (Typically used to silence a compiler warning when the assignment
72// is important for some other reason.)
73// Use like:
74//   int x ALLOW_UNUSED = ...;
75#if defined(COMPILER_GCC)
76#define ALLOW_UNUSED __attribute__((unused))
77#define NOINLINE __attribute__((noinline))
78#else
79#define ALLOW_UNUSED
80#define NOINLINE
81#endif
82
83// Annotate a virtual method indicating it must be overriding a virtual
84// method in the parent class.
85// Use like:
86//   virtual void foo() OVERRIDE;
87#if defined(COMPILER_MSVC)
88#define OVERRIDE override
89#elif defined(__clang__)
90#define OVERRIDE override
91#else
92#define OVERRIDE
93#endif
94
95// Annotate a function indicating the caller must examine the return value.
96// Use like:
97//   int foo() WARN_UNUSED_RESULT;
98#if defined(COMPILER_GCC)
99#define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
100#else
101#define WARN_UNUSED_RESULT
102#endif
103
104// Tell the compiler a function is using a printf-style format string.
105// |format_param| is the one-based index of the format string parameter;
106// |dots_param| is the one-based index of the "..." parameter.
107// For v*printf functions (which take a va_list), pass 0 for dots_param.
108// (This is undocumented but matches what the system C headers do.)
109#if defined(COMPILER_GCC)
110#define PRINTF_FORMAT(format_param, dots_param) \
111    __attribute__((format(printf, format_param, dots_param)))
112#else
113#define PRINTF_FORMAT(format_param, dots_param)
114#endif
115
116// WPRINTF_FORMAT is the same, but for wide format strings.
117// This doesn't appear to yet be implemented in any compiler.
118// See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38308 .
119#define WPRINTF_FORMAT(format_param, dots_param)
120// If available, it would look like:
121//   __attribute__((format(wprintf, format_param, dots_param)))
122
123#endif  // BASE_COMPILER_SPECIFIC_H_
124