DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Implementations of various class and method modifier attributes. */

#ifndef mozilla_Attributes_h_
#define mozilla_Attributes_h_

/*
 * This header does not include any other headers so that it can be included by
 * code that is (only currently) mfbt-incompatible.
 */

/*
 * MOZ_INLINE is a macro which expands to tell the compiler that the method
 * decorated with it should be inlined.  This macro is usable from C and C++
 * code, even though C89 does not support the |inline| keyword.  The compiler
 * may ignore this directive if it chooses.
 */
#if defined(__cplusplus)
#  define MOZ_INLINE            inline
#elif defined(_MSC_VER)
#  define MOZ_INLINE            __inline
#elif defined(__GNUC__)
#  define MOZ_INLINE            __inline__
#else
#  define MOZ_INLINE            inline
#endif

/*
 * MOZ_ALWAYS_INLINE is a macro which expands to tell the compiler that the
 * method decorated with it must be inlined, even if the compiler thinks
 * otherwise.  This is only a (much) stronger version of the MOZ_INLINE hint:
 * compilers are not guaranteed to respect it (although they're much more likely
 * to do so).
 */
#if defined(DEBUG)
#  define MOZ_ALWAYS_INLINE     MOZ_INLINE
#elif defined(_MSC_VER)
#  define MOZ_ALWAYS_INLINE     __forceinline
#elif defined(__GNUC__)
#  define MOZ_ALWAYS_INLINE     __attribute__((always_inline)) MOZ_INLINE
#else
#  define MOZ_ALWAYS_INLINE     MOZ_INLINE
#endif

/*
 * g++ requires -std=c++0x or -std=gnu++0x to support C++11 functionality
 * without warnings (functionality used by the macros below).  These modes are
 * detectable by checking whether __GXX_EXPERIMENTAL_CXX0X__ is defined or, more
 * standardly, by checking whether __cplusplus has a C++11 or greater value.
 * Current versions of g++ do not correctly set __cplusplus, so we check both
 * for forward compatibility.
 */
#if defined(__clang__)
   /*
    * Per Clang documentation, "Note that marketing version numbers should not
    * be used to check for language features, as different vendors use different
    * numbering schemes. Instead, use the feature checking macros."
    */
#  ifndef __has_extension
#    define __has_extension __has_feature /* compatibility, for older versions of clang */
#  endif
#  if __has_extension(cxx_deleted_functions)
#    define MOZ_HAVE_CXX11_DELETE
#  endif
#  if __has_extension(cxx_override_control)
#    define MOZ_HAVE_CXX11_OVERRIDE
#    define MOZ_HAVE_CXX11_FINAL         final
#  endif
#  if __has_extension(cxx_strong_enums)
#    define MOZ_HAVE_CXX11_ENUM_TYPE
#    define MOZ_HAVE_CXX11_STRONG_ENUMS
#  endif
#  if __has_attribute(noinline)
#    define MOZ_HAVE_NEVER_INLINE        __attribute__((noinline))
#  endif
#  if __has_attribute(noreturn)
#    define MOZ_HAVE_NORETURN            __attribute__((noreturn))
#  endif
#elif defined(__GNUC__)
#  if defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L
#    if __GNUC__ > 4
#      define MOZ_HAVE_CXX11_DELETE
#      define MOZ_HAVE_CXX11_OVERRIDE
#      define MOZ_HAVE_CXX11_FINAL       final
#    elif __GNUC__ == 4
#      if __GNUC_MINOR__ >= 7
#        define MOZ_HAVE_CXX11_OVERRIDE
#        define MOZ_HAVE_CXX11_FINAL     final
#      endif
#      if __GNUC_MINOR__ >= 4
#        define MOZ_HAVE_CXX11_DELETE
#        define MOZ_HAVE_CXX11_ENUM_TYPE
#        define MOZ_HAVE_CXX11_STRONG_ENUMS
#      endif
#    endif
#  else
     /* __final is a non-C++11 GCC synonym for 'final', per GCC r176655. */
#    if __GNUC__ > 4
#      define MOZ_HAVE_CXX11_FINAL       __final
#    elif __GNUC__ == 4
#      if __GNUC_MINOR__ >= 7
#        define MOZ_HAVE_CXX11_FINAL     __final
#      endif
#    endif
#  endif
#  define MOZ_HAVE_NEVER_INLINE          __attribute__((noinline))
#  define MOZ_HAVE_NORETURN              __attribute__((noreturn))
#elif defined(_MSC_VER)
#  if _MSC_VER >= 1400
#    define MOZ_HAVE_CXX11_OVERRIDE
     /* MSVC currently spells "final" as "sealed". */
#    define MOZ_HAVE_CXX11_FINAL         sealed
#    define MOZ_HAVE_CXX11_ENUM_TYPE
#  endif
#  if _MSC_VER >= 1700
#    define MOZ_HAVE_CXX11_STRONG_ENUMS
#  endif
#  define MOZ_HAVE_NEVER_INLINE          __declspec(noinline)
#  define MOZ_HAVE_NORETURN              __declspec(noreturn)
#endif

/*
 * MOZ_NEVER_INLINE is a macro which expands to tell the compiler that the
 * method decorated with it must never be inlined, even if the compiler would
 * otherwise choose to inline the method.  Compilers aren't absolutely
 * guaranteed to support this, but most do.
 */
#if defined(MOZ_HAVE_NEVER_INLINE)
#  define MOZ_NEVER_INLINE      MOZ_HAVE_NEVER_INLINE
#else
#  define MOZ_NEVER_INLINE      /* no support */
#endif

/*
 * MOZ_NORETURN, specified at the start of a function declaration, indicates
 * that the given function does not return.  (The function definition does not
 * need to be annotated.)
 *
 *   MOZ_NORETURN void abort(const char* msg);
 *
 * This modifier permits the compiler to optimize code assuming a call to such a
 * function will never return.  It also enables the compiler to avoid spurious
 * warnings about not initializing variables, or about any other seemingly-dodgy
 * operations performed after the function returns.
 *
 * This modifier does not affect the corresponding function's linking behavior.
 */
#if defined(MOZ_HAVE_NORETURN)
#  define MOZ_NORETURN          MOZ_HAVE_NORETURN
#else
#  define MOZ_NORETURN          /* no support */
#endif

/*
 * MOZ_ASAN_BLACKLIST is a macro to tell AddressSanitizer (a compile-time
 * instrumentation shipped with Clang) to not instrument the annotated function.
 * Furthermore, it will prevent the compiler from inlining the function because
 * inlining currently breaks the blacklisting mechanism of AddressSanitizer.
 */
#if defined(MOZ_ASAN)
#  define MOZ_ASAN_BLACKLIST MOZ_NEVER_INLINE __attribute__((no_address_safety_analysis))
# else
#  define MOZ_ASAN_BLACKLIST
#endif


#ifdef __cplusplus

/*
 * MOZ_DELETE, specified immediately prior to the ';' terminating an undefined-
 * method declaration, attempts to delete that method from the corresponding
 * class.  An attempt to use the method will always produce an error *at compile
 * time* (instead of sometimes as late as link time) when this macro can be
 * implemented.  For example, you can use MOZ_DELETE to produce classes with no
 * implicit copy constructor or assignment operator:
 *
 *   struct NonCopyable
 *   {
 *     private:
 *       NonCopyable(const NonCopyable& other) MOZ_DELETE;
 *       void operator=(const NonCopyable& other) MOZ_DELETE;
 *   };
 *
 * If MOZ_DELETE can't be implemented for the current compiler, use of the
 * annotated method will still cause an error, but the error might occur at link
 * time in some cases rather than at compile time.
 *
 * MOZ_DELETE relies on C++11 functionality not universally implemented.  As a
 * backstop, method declarations using MOZ_DELETE should be private.
 */
#if defined(MOZ_HAVE_CXX11_DELETE)
#  define MOZ_DELETE            = delete
#else
#  define MOZ_DELETE            /* no support */
#endif

/*
 * MOZ_OVERRIDE explicitly indicates that a virtual member function in a class
 * overrides a member function of a base class, rather than potentially being a
 * new member function.  MOZ_OVERRIDE should be placed immediately before the
 * ';' terminating the member function's declaration, or before '= 0;' if the
 * member function is pure.  If the member function is defined in the class
 * definition, it should appear before the opening brace of the function body.
 *
 *   class Base
 *   {
 *     public:
 *       virtual void f() = 0;
 *   };
 *   class Derived1 : public Base
 *   {
 *     public:
 *       virtual void f() MOZ_OVERRIDE;
 *   };
 *   class Derived2 : public Base
 *   {
 *     public:
 *       virtual void f() MOZ_OVERRIDE = 0;
 *   };
 *   class Derived3 : public Base
 *   {
 *     public:
 *       virtual void f() MOZ_OVERRIDE { }
 *   };
 *
 * In compilers supporting C++11 override controls, MOZ_OVERRIDE *requires* that
 * the function marked with it override a member function of a base class: it
 * is a compile error if it does not.  Otherwise MOZ_OVERRIDE does not affect
 * semantics and merely documents the override relationship to the reader (but
 * of course must still be used correctly to not break C++11 compilers).
 */
#if defined(MOZ_HAVE_CXX11_OVERRIDE)
#  define MOZ_OVERRIDE          override
#else
#  define MOZ_OVERRIDE          /* no support */
#endif

/*
 * MOZ_FINAL indicates that some functionality cannot be overridden through
 * inheritance.  It can be used to annotate either classes/structs or virtual
 * member functions.
 *
 * To annotate a class/struct with MOZ_FINAL, place MOZ_FINAL immediately after
 * the name of the class, before the list of classes from which it derives (if
 * any) and before its opening brace.  MOZ_FINAL must not be used to annotate
 * unnamed classes or structs.  (With some compilers, and with C++11 proper, the
 * underlying expansion is ambiguous with specifying a class name.)
 *
 *   class Base MOZ_FINAL
 *   {
 *     public:
 *       Base();
 *       ~Base();
 *       virtual void f() { }
 *   };
 *   // This will be an error in some compilers:
 *   class Derived : public Base
 *   {
 *     public:
 *       ~Derived() { }
 *   };
 *
 * One particularly common reason to specify MOZ_FINAL upon a class is to tell
 * the compiler that it's not dangerous for it to have a non-virtual destructor
 * yet have one or more virtual functions, silencing the warning it might emit
 * in this case.  Suppose Base above weren't annotated with MOZ_FINAL.  Because
 * ~Base() is non-virtual, an attempt to delete a Derived* through a Base*
 * wouldn't call ~Derived(), so any cleanup ~Derived() might do wouldn't happen.
 * (Formally C++ says behavior is undefined, but compilers will likely just call
 * ~Base() and not ~Derived().)  Specifying MOZ_FINAL tells the compiler that
 * it's safe for the destructor to be non-virtual.
 *
 * In compilers implementing final controls, it is an error to inherit from a
 * class annotated with MOZ_FINAL.  In other compilers it serves only as
 * documentation.
 *
 * To annotate a virtual member function with MOZ_FINAL, place MOZ_FINAL
 * immediately before the ';' terminating the member function's declaration, or
 * before '= 0;' if the member function is pure.  If the member function is
 * defined in the class definition, it should appear before the opening brace of
 * the function body.  (This placement is identical to that for MOZ_OVERRIDE.
 * If both are used, they should appear in the order 'MOZ_FINAL MOZ_OVERRIDE'
 * for consistency.)
 *
 *   class Base
 *   {
 *     public:
 *       virtual void f() MOZ_FINAL;
 *   };
 *   class Derived
 *   {
 *     public:
 *       // This will be an error in some compilers:
 *       virtual void f();
 *   };
 *
 * In compilers implementing final controls, it is an error for a derived class
 * to override a method annotated with MOZ_FINAL.  In other compilers it serves
 * only as documentation.
 */
#if defined(MOZ_HAVE_CXX11_FINAL)
#  define MOZ_FINAL             MOZ_HAVE_CXX11_FINAL
#else
#  define MOZ_FINAL             /* no support */
#endif

/**
 * MOZ_ENUM_TYPE specifies the underlying numeric type for an enum.  It's
 * specified by placing MOZ_ENUM_TYPE(type) immediately after the enum name in
 * its declaration, and before the opening curly brace, like
 *
 *   enum MyEnum MOZ_ENUM_TYPE(uint16_t)
 *   {
 *     A,
 *     B = 7,
 *     C
 *   };
 *
 * In supporting compilers, the macro will expand to ": uint16_t".  The
 * compiler will allocate exactly two bytes for MyEnum, and will require all
 * enumerators to have values between 0 and 65535.  (Thus specifying "B =
 * 100000" instead of "B = 7" would fail to compile.)  In old compilers, the
 * macro expands to the empty string, and the underlying type is generally
 * undefined.
 */
#ifdef MOZ_HAVE_CXX11_ENUM_TYPE
#  define MOZ_ENUM_TYPE(type)   : type
#else
#  define MOZ_ENUM_TYPE(type)   /* no support */
#endif

/**
 * MOZ_BEGIN_ENUM_CLASS and MOZ_END_ENUM_CLASS provide access to the
 * strongly-typed enumeration feature of C++11 ("enum class").  If supported
 * by the compiler, an enum defined using these macros will not be implicitly
 * converted to any other type, and its enumerators will be scoped using the
 * enumeration name.  Place MOZ_BEGIN_ENUM_CLASS(EnumName, type) in place of
 * "enum EnumName {", and MOZ_END_ENUM_CLASS(EnumName) in place of the closing
 * "};".  For example,
 *
 *   MOZ_BEGIN_ENUM_CLASS(Enum, int32_t)
 *     A, B = 6
 *   MOZ_END_ENUM_CLASS(Enum)
 *
 * This will make "Enum::A" and "Enum::B" appear in the global scope, but "A"
 * and "B" will not.  In compilers that support C++11 strongly-typed
 * enumerations, implicit conversions of Enum values to numeric types will
 * fail.  In other compilers, Enum itself will actually be defined as a class,
 * and some implicit conversions will fail while others will succeed.
 *
 * The type argument specifies the underlying type for the enum where
 * supported, as with MOZ_ENUM_TYPE().  For simplicity, it is currently
 * mandatory.  As with MOZ_ENUM_TYPE(), it will do nothing on compilers that do
 * not support it.
 */
#if defined(MOZ_HAVE_CXX11_STRONG_ENUMS)
  /* All compilers that support strong enums also support an explicit
   * underlying type, so no extra check is needed */
#  define MOZ_BEGIN_ENUM_CLASS(Name, type) enum class Name : type {
#  define MOZ_END_ENUM_CLASS(Name)         };
#else
   /**
    * We need Name to both name a type, and scope the provided enumerator
    * names.  Namespaces and classes both provide scoping, but namespaces
    * aren't types, so we need to use a class that wraps the enum values.  We
    * have an implicit conversion from the inner enum type to the class, so
    * statements like
    *
    *   Enum x = Enum::A;
    *
    * will still work.  We need to define an implicit conversion from the class
    * to the inner enum as well, so that (for instance) switch statements will
    * work.  This means that the class can be implicitly converted to a numeric
    * value as well via the enum type, since C++ allows an implicit
    * user-defined conversion followed by a standard conversion to still be
    * implicit.
    *
    * We have an explicit constructor from int defined, so that casts like
    * (Enum)7 will still work.  We also have a zero-argument constructor with
    * no arguments, so declaration without initialization (like "Enum foo;")
    * will work.
    *
    * Additionally, we'll delete as many operators as possible for the inner
    * enum type, so statements like this will still fail:
    *
    *   f(5 + Enum::B); // deleted operator+
    *
    * But we can't prevent things like this, because C++ doesn't allow
    * overriding conversions or assignment operators for enums:
    *
    *   int x = Enum::A;
    *   int f()
    *   {
    *     return Enum::A;
    *   }
    */
#  define MOZ_BEGIN_ENUM_CLASS(Name, type) \
     class Name \
     { \
       public: \
         enum Enum MOZ_ENUM_TYPE(type) \
         {
#  define MOZ_END_ENUM_CLASS(Name) \
         }; \
         Name() {} \
         Name(Enum aEnum) : mEnum(aEnum) {} \
         explicit Name(int num) : mEnum((Enum)num) {} \
         operator Enum() const { return mEnum; } \
       private: \
         Enum mEnum; \
     }; \
     inline int operator+(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator+(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator-(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator-(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator*(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator*(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator/(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator/(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator%(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator%(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator+(const Name::Enum&) MOZ_DELETE; \
     inline int operator-(const Name::Enum&) MOZ_DELETE; \
     inline int& operator++(Name::Enum&) MOZ_DELETE; \
     inline int operator++(Name::Enum&, int) MOZ_DELETE; \
     inline int& operator--(Name::Enum&) MOZ_DELETE; \
     inline int operator--(Name::Enum&, int) MOZ_DELETE; \
     inline bool operator==(const int&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator==(const Name::Enum&, const int&) MOZ_DELETE; \
     inline bool operator!=(const int&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator!=(const Name::Enum&, const int&) MOZ_DELETE; \
     inline bool operator>(const int&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator>(const Name::Enum&, const int&) MOZ_DELETE; \
     inline bool operator<(const int&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator<(const Name::Enum&, const int&) MOZ_DELETE; \
     inline bool operator>=(const int&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator>=(const Name::Enum&, const int&) MOZ_DELETE; \
     inline bool operator<=(const int&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator<=(const Name::Enum&, const int&) MOZ_DELETE; \
     inline bool operator!(const Name::Enum&) MOZ_DELETE; \
     inline bool operator&&(const bool&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator&&(const Name::Enum&, const bool&) MOZ_DELETE; \
     inline bool operator||(const bool&, const Name::Enum&) MOZ_DELETE; \
     inline bool operator||(const Name::Enum&, const bool&) MOZ_DELETE; \
     inline int operator~(const Name::Enum&) MOZ_DELETE; \
     inline int operator&(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator&(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator|(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator|(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator^(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator^(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator<<(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator<<(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int operator>>(const int&, const Name::Enum&) MOZ_DELETE; \
     inline int operator>>(const Name::Enum&, const int&) MOZ_DELETE; \
     inline int& operator+=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator-=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator*=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator/=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator%=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator&=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator|=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator^=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator<<=(int&, const Name::Enum&) MOZ_DELETE; \
     inline int& operator>>=(int&, const Name::Enum&) MOZ_DELETE;
#endif

/**
 * MOZ_WARN_UNUSED_RESULT tells the compiler to emit a warning if a function's
 * return value is not used by the caller.
 *
 * Place this attribute at the very beginning of a function definition. For
 * example, write
 *
 *   MOZ_WARN_UNUSED_RESULT int foo();
 *
 * or
 *
 *   MOZ_WARN_UNUSED_RESULT int foo() { return 42; }
 */
#if defined(__GNUC__) || defined(__clang__)
#  define MOZ_WARN_UNUSED_RESULT __attribute__ ((warn_unused_result))
#else
#  define MOZ_WARN_UNUSED_RESULT
#endif

#endif /* __cplusplus */

#endif  /* mozilla_Attributes_h_ */