1// Copyright (c) 2012 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 BUTIL_COMPILER_SPECIFIC_H_
6#define BUTIL_COMPILER_SPECIFIC_H_
7
8#include "butil/build_config.h"
9
10#if defined(COMPILER_MSVC)
11
12// Macros for suppressing and disabling warnings on MSVC.
13//
14// Warning numbers are enumerated at:
15// http://msdn.microsoft.com/en-us/library/8x5x43k7(VS.80).aspx
16//
17// The warning pragma:
18// http://msdn.microsoft.com/en-us/library/2c8f766e(VS.80).aspx
19//
20// Using __pragma instead of #pragma inside macros:
21// http://msdn.microsoft.com/en-us/library/d9x1s805.aspx
22
23// MSVC_SUPPRESS_WARNING disables warning |n| for the remainder of the line and
24// for the next line of the source file.
25#define MSVC_SUPPRESS_WARNING(n) __pragma(warning(suppress:n))
26
27// MSVC_PUSH_DISABLE_WARNING pushes |n| onto a stack of warnings to be disabled.
28// The warning remains disabled until popped by MSVC_POP_WARNING.
29#define MSVC_PUSH_DISABLE_WARNING(n) __pragma(warning(push)) \
30 __pragma(warning(disable:n))
31
32// MSVC_PUSH_WARNING_LEVEL pushes |n| as the global warning level. The level
33// remains in effect until popped by MSVC_POP_WARNING(). Use 0 to disable all
34// warnings.
35#define MSVC_PUSH_WARNING_LEVEL(n) __pragma(warning(push, n))
36
37// Pop effects of innermost MSVC_PUSH_* macro.
38#define MSVC_POP_WARNING() __pragma(warning(pop))
39
40#define MSVC_DISABLE_OPTIMIZE() __pragma(optimize("", off))
41#define MSVC_ENABLE_OPTIMIZE() __pragma(optimize("", on))
42
43// Allows exporting a class that inherits from a non-exported base class.
44// This uses suppress instead of push/pop because the delimiter after the
45// declaration (either "," or "{") has to be placed before the pop macro.
46//
47// Example usage:
48// class EXPORT_API Foo : NON_EXPORTED_BASE(public Bar) {
49//
50// MSVC Compiler warning C4275:
51// non dll-interface class 'Bar' used as base for dll-interface class 'Foo'.
52// Note that this is intended to be used only when no access to the base class'
53// static data is done through derived classes or inline methods. For more info,
54// see http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx
55#define NON_EXPORTED_BASE(code) MSVC_SUPPRESS_WARNING(4275) \
56 code
57
58#else // Not MSVC
59
60#define MSVC_SUPPRESS_WARNING(n)
61#define MSVC_PUSH_DISABLE_WARNING(n)
62#define MSVC_PUSH_WARNING_LEVEL(n)
63#define MSVC_POP_WARNING()
64#define MSVC_DISABLE_OPTIMIZE()
65#define MSVC_ENABLE_OPTIMIZE()
66#define NON_EXPORTED_BASE(code) code
67
68#endif // COMPILER_MSVC
69
70
71// The C++ standard requires that static const members have an out-of-class
72// definition (in a single compilation unit), but MSVC chokes on this (when
73// language extensions, which are required, are enabled). (You're only likely to
74// notice the need for a definition if you take the address of the member or,
75// more commonly, pass it to a function that takes it as a reference argument --
76// probably an STL function.) This macro makes MSVC do the right thing. See
77// http://msdn.microsoft.com/en-us/library/34h23df8(v=vs.100).aspx for more
78// information. Use like:
79//
80// In .h file:
81// struct Foo {
82// static const int kBar = 5;
83// };
84//
85// In .cc file:
86// STATIC_CONST_MEMBER_DEFINITION const int Foo::kBar;
87#if defined(COMPILER_MSVC)
88#define STATIC_CONST_MEMBER_DEFINITION __declspec(selectany)
89#else
90#define STATIC_CONST_MEMBER_DEFINITION
91#endif
92
93// Annotate a variable indicating it's ok if the variable is not used.
94// (Typically used to silence a compiler warning when the assignment
95// is important for some other reason.)
96// Use like:
97// int x ALLOW_UNUSED = ...;
98#if defined(COMPILER_GCC)
99#define ALLOW_UNUSED __attribute__((unused))
100#else
101#define ALLOW_UNUSED
102#endif
103
104// Annotate a function indicating it should not be inlined.
105// Use like:
106// NOINLINE void DoStuff() { ... }
107#if defined(COMPILER_GCC)
108#define NOINLINE __attribute__((noinline))
109#elif defined(COMPILER_MSVC)
110#define NOINLINE __declspec(noinline)
111#else
112#define NOINLINE
113#endif
114
115#ifndef BUTIL_FORCE_INLINE
116#if defined(COMPILER_MSVC)
117#define BUTIL_FORCE_INLINE __forceinline
118#else
119#define BUTIL_FORCE_INLINE inline __attribute__((always_inline))
120#endif
121#endif // BUTIL_FORCE_INLINE
122
123// Specify memory alignment for structs, classes, etc.
124// Use like:
125// class ALIGNAS(16) MyClass { ... }
126// ALIGNAS(16) int array[4];
127#if defined(COMPILER_MSVC)
128#define ALIGNAS(byte_alignment) __declspec(align(byte_alignment))
129#elif defined(COMPILER_GCC)
130#define ALIGNAS(byte_alignment) __attribute__((aligned(byte_alignment)))
131#endif
132
133// Return the byte alignment of the given type (available at compile time). Use
134// sizeof(type) prior to checking __alignof to workaround Visual C++ bug:
135// http://goo.gl/isH0C
136// Use like:
137// ALIGNOF(int32_t) // this would be 4
138#if defined(COMPILER_MSVC)
139#define ALIGNOF(type) (sizeof(type) - sizeof(type) + __alignof(type))
140#elif defined(COMPILER_GCC)
141#define ALIGNOF(type) __alignof__(type)
142#endif
143
144// Annotate a virtual method indicating it must be overriding a virtual
145// method in the parent class.
146// Use like:
147// virtual void foo() OVERRIDE;
148#if defined(__clang__) || defined(COMPILER_MSVC)
149#define OVERRIDE override
150#elif defined(COMPILER_GCC) && __cplusplus >= 201103 && \
151 (__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40700
152// GCC 4.7 supports explicit virtual overrides when C++11 support is enabled.
153#define OVERRIDE override
154#else
155#define OVERRIDE
156#endif
157
158// Annotate a virtual method indicating that subclasses must not override it,
159// or annotate a class to indicate that it cannot be subclassed.
160// Use like:
161// virtual void foo() FINAL;
162// class B FINAL : public A {};
163#if defined(__clang__) || defined(COMPILER_MSVC)
164#define FINAL final
165#elif defined(COMPILER_GCC) && __cplusplus >= 201103 && \
166 (__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40700
167// GCC 4.7 supports explicit virtual overrides when C++11 support is enabled.
168#define FINAL final
169#else
170#define FINAL
171#endif
172
173// Annotate a function indicating the caller must examine the return value.
174// Use like:
175// int foo() WARN_UNUSED_RESULT;
176// To explicitly ignore a result, see |ignore_result()| in "butil/basictypes.h".
177// FIXME(gejun): GCC 3.4 report "unused" variable incorrectly (actually used).
178#if defined(COMPILER_GCC) && __cplusplus >= 201103 && \
179 (__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40700
180#define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
181#else
182#define WARN_UNUSED_RESULT
183#endif
184
185// Tell the compiler a function is using a printf-style format string.
186// |format_param| is the one-based index of the format string parameter;
187// |dots_param| is the one-based index of the "..." parameter.
188// For v*printf functions (which take a va_list), pass 0 for dots_param.
189// (This is undocumented but matches what the system C headers do.)
190#if defined(COMPILER_GCC)
191#define PRINTF_FORMAT(format_param, dots_param) \
192 __attribute__((format(printf, format_param, dots_param)))
193#else
194#define PRINTF_FORMAT(format_param, dots_param)
195#endif
196
197// WPRINTF_FORMAT is the same, but for wide format strings.
198// This doesn't appear to yet be implemented in any compiler.
199// See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38308 .
200#define WPRINTF_FORMAT(format_param, dots_param)
201// If available, it would look like:
202// __attribute__((format(wprintf, format_param, dots_param)))
203
204// MemorySanitizer annotations.
205#if defined(MEMORY_SANITIZER) && !defined(OS_NACL)
206#include <sanitizer/msan_interface.h>
207
208// Mark a memory region fully initialized.
209// Use this to annotate code that deliberately reads uninitialized data, for
210// example a GC scavenging root set pointers from the stack.
211#define MSAN_UNPOISON(p, s) __msan_unpoison(p, s)
212#else // MEMORY_SANITIZER
213#define MSAN_UNPOISON(p, s)
214#endif // MEMORY_SANITIZER
215
216// Macro useful for writing cross-platform function pointers.
217#if !defined(CDECL)
218#if defined(OS_WIN)
219#define CDECL __cdecl
220#else // defined(OS_WIN)
221#define CDECL
222#endif // defined(OS_WIN)
223#endif // !defined(CDECL)
224
225// Mark a branch likely or unlikely to be true.
226// We can't remove the BAIDU_ prefix because the name is likely to conflict,
227// namely kylin already has the macro.
228#if defined(COMPILER_GCC)
229# if defined(__cplusplus)
230# define BAIDU_LIKELY(expr) (__builtin_expect((bool)(expr), true))
231# define BAIDU_UNLIKELY(expr) (__builtin_expect((bool)(expr), false))
232# else
233# define BAIDU_LIKELY(expr) (__builtin_expect(!!(expr), 1))
234# define BAIDU_UNLIKELY(expr) (__builtin_expect(!!(expr), 0))
235# endif
236#else
237# define BAIDU_LIKELY(expr) (expr)
238# define BAIDU_UNLIKELY(expr) (expr)
239#endif
240
241// BAIDU_DEPRECATED void dont_call_me_anymore(int arg);
242// ...
243// warning: 'void dont_call_me_anymore(int)' is deprecated
244#if defined(COMPILER_GCC)
245# define BAIDU_DEPRECATED __attribute__((deprecated))
246#elif defined(COMPILER_MSVC)
247# define BAIDU_DEPRECATED __declspec(deprecated)
248#else
249# define BAIDU_DEPRECATED
250#endif
251
252// Mark function as weak. This is GCC only feature.
253#if defined(COMPILER_GCC)
254# define BAIDU_WEAK __attribute__((weak))
255#else
256# define BAIDU_WEAK
257#endif
258
259// Cacheline related --------------------------------------
260#define BAIDU_CACHELINE_SIZE 64
261
262#ifdef _MSC_VER
263# define BAIDU_CACHELINE_ALIGNMENT __declspec(align(BAIDU_CACHELINE_SIZE))
264#endif /* _MSC_VER */
265
266#ifdef __GNUC__
267# define BAIDU_CACHELINE_ALIGNMENT __attribute__((aligned(BAIDU_CACHELINE_SIZE)))
268#endif /* __GNUC__ */
269
270#ifndef BAIDU_CACHELINE_ALIGNMENT
271# define BAIDU_CACHELINE_ALIGNMENT /*BAIDU_CACHELINE_ALIGNMENT*/
272#endif
273
274#ifndef BAIDU_NOEXCEPT
275# if defined(BUTIL_CXX11_ENABLED)
276# define BAIDU_NOEXCEPT noexcept
277# else
278# define BAIDU_NOEXCEPT
279# endif
280#endif
281
282#endif // BUTIL_COMPILER_SPECIFIC_H_
283