win: Fix InitializationStateDcheck in Release build

util/misc/initialization_state_dcheck.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_UTIL_MISC_INITIALIZATION_INITIALIZATION_STATE_DCHECK_H_
 #define CRASHPAD_UTIL_MISC_INITIALIZATION_INITIALIZATION_STATE_DCHECK_H_
 
 //! \file
 
 #include "base/basictypes.h"
+#include "base/compiler_specific.h"
 #include "base/logging.h"
+#include "build/build_config.h"
 #include "util/misc/initialization_state.h"
 
 namespace crashpad {
 
 #if DCHECK_IS_ON || DOXYGEN
 
 //! \brief Tracks whether data are initialized, triggering a DCHECK assertion
 //!     on an invalid data access.
 //!
 //! Put an InitializationStateDcheck member into a class to help DCHECK that
@@ skipping 115 matching lines @@
 //! \param[in] initialization_state_dcheck A crashpad::InitializationStateDcheck
 //!     object.
 //!
 //! \sa crashpad::InitializationStateDcheck
 #define INITIALIZATION_STATE_DCHECK_VALID(initialization_state_dcheck) \
   DCHECK_EQ((initialization_state_dcheck).state(),                     \
             (initialization_state_dcheck).kStateValid)
 
 #else
 
+#if defined(COMPILER_MSVC)
+// bool[0] (below) is not accepted by MSVC.
+struct InitializationStateDcheck {
+};
+#else
 // Since this is to be used as a DCHECK (for debugging), it should be
 // non-intrusive in non-DCHECK (non-debug, release) builds. An empty struct
 // would still have a nonzero size (rationale:
 // http://www.stroustrup.com/bs_faq2.html#sizeof-empty). Zero-length arrays are
 // technically invalid according to the standard, but clang and g++ accept them
 // without complaint even with warnings turned up. They take up no space at all,
 // and they can be “initialized” with the same () syntax used to initialize
 // objects of the DCHECK_IS_ON InitializationStateDcheck class above.
 using InitializationStateDcheck = bool[0];
+#endif  // COMPILER_MSVC
 
-namespace internal {
-
-// This function exists to make use of the InitializationStateDcheck object so
-// that it appears to be used. It always returns true, so that it can be used
-// as the argument to a no-op DCHECK.
-inline bool EatInitializationState(const InitializationStateDcheck*) {
-  return true;
-}
-
-}  // namepspace internal
-
-// The contents of these DCHECKs will never be evaluated, but they make use of
-// initialization_state_dcheck to avoid triggering -Wunused-private-field
-// warnings.
+// Avoid triggering warnings by repurposing these macros when DCHECKs are
+// disabled.
 #define INITIALIZATION_STATE_SET_INITIALIZING(initialization_state_dcheck) \
-  DCHECK(::crashpad::internal::EatInitializationState( \
-      &(initialization_state_dcheck)))
+  ALLOW_UNUSED_LOCAL(initialization_state_dcheck)
 #define INITIALIZATION_STATE_SET_VALID(initialization_state_dcheck) \
-  DCHECK(::crashpad::internal::EatInitializationState( \
-      &(initialization_state_dcheck)))
+  ALLOW_UNUSED_LOCAL(initialization_state_dcheck)
 #define INITIALIZATION_STATE_DCHECK_VALID(initialization_state_dcheck) \
-  DCHECK(::crashpad::internal::EatInitializationState( \
-      &(initialization_state_dcheck)))
+  ALLOW_UNUSED_LOCAL(initialization_state_dcheck)
 
 #endif
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_MISC_INITIALIZATION_INITIALIZATION_STATE_DCHECK_H_