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 // Copyright (c) 2012 The Chromium 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 BASE_COMPILER_SPECIFIC_H_

 #define BASE_COMPILER_SPECIFIC_H_

 #include "build/build_config.h"

 #if defined(COMPILER_MSVC)

 // Macros for suppressing and disabling warnings on MSVC.

 //

 // Warning numbers are enumerated at:

 // http://msdn.microsoft.com/en-us/library/8x5x43k7(VS.80).aspx

 //

 // The warning pragma:

 // http://msdn.microsoft.com/en-us/library/2c8f766e(VS.80).aspx

 //

 // Using __pragma instead of #pragma inside macros:

 // http://msdn.microsoft.com/en-us/library/d9x1s805.aspx

 // MSVC_SUPPRESS_WARNING disables warning |n| for the remainder of the line and

 // for the next line of the source file.

 #define MSVC_SUPPRESS_WARNING(n) __pragma(warning(suppress:n))

 // MSVC_PUSH_DISABLE_WARNING pushes |n| onto a stack of warnings to be disabled.

 // The warning remains disabled until popped by MSVC_POP_WARNING.

 #define MSVC_PUSH_DISABLE_WARNING(n) __pragma(warning(push)) \

                                      __pragma(warning(disable:n))

 // MSVC_PUSH_WARNING_LEVEL pushes |n| as the global warning level.  The level

 // remains in effect until popped by MSVC_POP_WARNING().  Use 0 to disable all

 // warnings.

 #define MSVC_PUSH_WARNING_LEVEL(n) __pragma(warning(push, n))

 // Pop effects of innermost MSVC_PUSH_* macro.

 #define MSVC_POP_WARNING() __pragma(warning(pop))

 #define MSVC_DISABLE_OPTIMIZE() __pragma(optimize("", off))

 #define MSVC_ENABLE_OPTIMIZE() __pragma(optimize("", on))

 // Allows exporting a class that inherits from a non-exported base class.

 // This uses suppress instead of push/pop because the delimiter after the

 // declaration (either "," or "{") has to be placed before the pop macro.

 //

 // Example usage:

 // class EXPORT_API Foo : NON_EXPORTED_BASE(public Bar) {

 //

 // MSVC Compiler warning C4275:

 // non dll-interface class 'Bar' used as base for dll-interface class 'Foo'.

 // Note that this is intended to be used only when no access to the base class'

 // static data is done through derived classes or inline methods. For more info,

 // see http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx

 #define NON_EXPORTED_BASE(code) MSVC_SUPPRESS_WARNING(4275) \

                                 code

 #else  // Not MSVC

 #define MSVC_SUPPRESS_WARNING(n)

 #define MSVC_PUSH_DISABLE_WARNING(n)

 #define MSVC_PUSH_WARNING_LEVEL(n)

 #define MSVC_POP_WARNING()

 #define MSVC_DISABLE_OPTIMIZE()

 #define MSVC_ENABLE_OPTIMIZE()

 #define NON_EXPORTED_BASE(code) code

 #endif  // COMPILER_MSVC

 // Annotate a variable indicating it's ok if the variable is not used.

 // (Typically used to silence a compiler warning when the assignment

 // is important for some other reason.)

 // Use like:

 //   int x ALLOW_UNUSED = ...;

 #if defined(COMPILER_GCC)

 #define ALLOW_UNUSED __attribute__((unused))

 #else

 #define ALLOW_UNUSED

 #endif

 // Annotate a function indicating it should not be inlined.

 // Use like:

 //   NOINLINE void DoStuff() { ... }

 #if defined(COMPILER_GCC)

 #define NOINLINE __attribute__((noinline))

 #elif defined(COMPILER_MSVC)

 #define NOINLINE __declspec(noinline)

 #else

 #define NOINLINE

 #endif

 // Specify memory alignment for structs, classes, etc.

 // Use like:

 //   class ALIGNAS(16) MyClass { ... }

 //   ALIGNAS(16) int array[4];

 #if defined(COMPILER_MSVC)

 #define ALIGNAS(byte_alignment) __declspec(align(byte_alignment))

 #elif defined(COMPILER_GCC)

 #define ALIGNAS(byte_alignment) __attribute__((aligned(byte_alignment)))

 #endif

 // Return the byte alignment of the given type (available at compile time).  Use

 // sizeof(type) prior to checking __alignof to workaround Visual C++ bug:

 // http://goo.gl/isH0C

 // Use like:

 //   ALIGNOF(int32)  // this would be 4

 #if defined(COMPILER_MSVC)

 #define ALIGNOF(type) (sizeof(type) - sizeof(type) + __alignof(type))

 #elif defined(COMPILER_GCC)

 #define ALIGNOF(type) __alignof__(type)

 #endif

 // Annotate a virtual method indicating it must be overriding a virtual

 // method in the parent class.

 // Use like:

 //   virtual void foo() OVERRIDE;

 #if defined(COMPILER_MSVC)

 #define OVERRIDE override

 #elif defined(__clang__)

 #define OVERRIDE override

 #else

 #define OVERRIDE

 #endif

 // Annotate a virtual method indicating that subclasses must not override it,

 // or annotate a class to indicate that it cannot be subclassed.

 // Use like:

 //   virtual void foo() FINAL;

 //   class B FINAL : public A {};

 #if defined(COMPILER_MSVC)

 // TODO(jered): Change this to "final" when chromium no longer uses MSVC 2010.

 #define FINAL sealed

 #elif defined(__clang__)

 #define FINAL final

 #else

 #define FINAL

 #endif

 // Annotate a function indicating the caller must examine the return value.

 // Use like:

 //   int foo() WARN_UNUSED_RESULT;

 // To explicitly ignore a result, see |ignore_result()| in <base/basictypes.h>.

 #if defined(COMPILER_GCC)

 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))

 #else

 #define WARN_UNUSED_RESULT

 #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(COMPILER_GCC)

 #define PRINTF_FORMAT(format_param, dots_param) \

     __attribute__((format(printf, format_param, dots_param)))

 #else

 #define PRINTF_FORMAT(format_param, dots_param)

 #endif

 // WPRINTF_FORMAT is the same, but for wide format strings.

 // This doesn't appear to yet be implemented in any compiler.

 // See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38308 .

 #define WPRINTF_FORMAT(format_param, dots_param)

 // If available, it would look like:

 //   __attribute__((format(wprintf, format_param, dots_param)))

 // MemorySanitizer annotations.

 #ifdef MEMORY_SANITIZER

 extern "C" {

 void __msan_unpoison(const void *p, unsigned long s);

 }  // extern "C"

 // Mark a memory region fully initialized.

 // Use this to annotate code that deliberately reads uninitialized data, for

 // example a GC scavenging root set pointers from the stack.

 #define MSAN_UNPOISON(p, s)  __msan_unpoison(p, s)

 #else  // MEMORY_SANITIZER

 #define MSAN_UNPOISON(p, s)

 #endif  // MEMORY_SANITIZER

 #endif  // BASE_COMPILER_SPECIFIC_H_