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 BASE_COMPILER_SPECIFIC_H_ 6 #define BASE_COMPILER_SPECIFIC_H_ 7 8 #include "build/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 // Specify memory alignment for structs, classes, etc. 116 // Use like: 117 // class ALIGNAS(16) MyClass { ... } 118 // ALIGNAS(16) int array[4]; 119 #if defined(COMPILER_MSVC) 120 #define ALIGNAS(byte_alignment) __declspec(align(byte_alignment)) 121 #elif defined(COMPILER_GCC) 122 #define ALIGNAS(byte_alignment) __attribute__((aligned(byte_alignment))) 123 #endif 124 125 // Return the byte alignment of the given type (available at compile time). Use 126 // sizeof(type) prior to checking __alignof to workaround Visual C++ bug: 127 // http://goo.gl/isH0C 128 // Use like: 129 // ALIGNOF(int32) // this would be 4 130 #if defined(COMPILER_MSVC) 131 #define ALIGNOF(type) (sizeof(type) - sizeof(type) + __alignof(type)) 132 #elif defined(COMPILER_GCC) 133 #define ALIGNOF(type) __alignof__(type) 134 #endif 135 136 // Annotate a virtual method indicating it must be overriding a virtual 137 // method in the parent class. 138 // Use like: 139 // virtual void foo() OVERRIDE; 140 #define OVERRIDE override 141 142 // Annotate a virtual method indicating that subclasses must not override it, 143 // or annotate a class to indicate that it cannot be subclassed. 144 // Use like: 145 // virtual void foo() FINAL; 146 // class B FINAL : public A {}; 147 #define FINAL final 148 149 // Annotate a function indicating the caller must examine the return value. 150 // Use like: 151 // int foo() WARN_UNUSED_RESULT; 152 // To explicitly ignore a result, see |ignore_result()| in <base/basictypes.h>. 153 #if defined(COMPILER_GCC) 154 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result)) 155 #else 156 #define WARN_UNUSED_RESULT 157 #endif 158 159 // Tell the compiler a function is using a printf-style format string. 160 // |format_param| is the one-based index of the format string parameter; 161 // |dots_param| is the one-based index of the "..." parameter. 162 // For v*printf functions (which take a va_list), pass 0 for dots_param. 163 // (This is undocumented but matches what the system C headers do.) 164 #if defined(COMPILER_GCC) 165 #define PRINTF_FORMAT(format_param, dots_param) \ 166 __attribute__((format(printf, format_param, dots_param))) 167 #else 168 #define PRINTF_FORMAT(format_param, dots_param) 169 #endif 170 171 // WPRINTF_FORMAT is the same, but for wide format strings. 172 // This doesn't appear to yet be implemented in any compiler. 173 // See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38308 . 174 #define WPRINTF_FORMAT(format_param, dots_param) 175 // If available, it would look like: 176 // __attribute__((format(wprintf, format_param, dots_param))) 177 178 // MemorySanitizer annotations. 179 #if defined(MEMORY_SANITIZER) && !defined(OS_NACL) 180 #include <sanitizer/msan_interface.h> 181 182 // Mark a memory region fully initialized. 183 // Use this to annotate code that deliberately reads uninitialized data, for 184 // example a GC scavenging root set pointers from the stack. 185 #define MSAN_UNPOISON(p, s) __msan_unpoison(p, s) 186 #else // MEMORY_SANITIZER 187 #define MSAN_UNPOISON(p, s) 188 #endif // MEMORY_SANITIZER 189 190 // Macro useful for writing cross-platform function pointers. 191 #if !defined(CDECL) 192 #if defined(OS_WIN) 193 #define CDECL __cdecl 194 #else // defined(OS_WIN) 195 #define CDECL 196 #endif // defined(OS_WIN) 197 #endif // !defined(CDECL) 198 199 // Macro for hinting that an expression is likely to be false. 200 #if !defined(UNLIKELY) 201 #if defined(COMPILER_GCC) 202 #define UNLIKELY(x) __builtin_expect(!!(x), 0) 203 #else 204 #define UNLIKELY(x) (x) 205 #endif // defined(COMPILER_GCC) 206 #endif // !defined(UNLIKELY) 207 208 #endif // BASE_COMPILER_SPECIFIC_H_ 209
