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+// Copyright (c) 2011 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_
+#pragma once
+
+#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 |this| to be passed as an argument in constructor initializer lists.
+// This uses push/pop instead of the seemingly simpler suppress feature to avoid
+// having the warning be disabled for more than just |code|.
+//
+// Example usage:
+// Foo::Foo() : x(NULL), ALLOW_THIS_IN_INITIALIZER_LIST(y(this)), z(3) {}
+//
+// Compiler warning C4355: 'this': used in base member initializer list:
+// http://msdn.microsoft.com/en-us/library/3c594ae3(VS.80).aspx
+#define ALLOW_THIS_IN_INITIALIZER_LIST(code) MSVC_PUSH_DISABLE_WARNING(4355) \
+ code \
+ MSVC_POP_WARNING()
+
+// 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
+// can be gained through the derived class. 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 ALLOW_THIS_IN_INITIALIZER_LIST(code) code
+#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))
+#define NOINLINE __attribute__((noinline))
+#else
+#define ALLOW_UNUSED
+#define NOINLINE
+#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 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)))
+
+#endif // BASE_COMPILER_SPECIFIC_H_