Test RTC_DCHECK_IS_ON instead of checking DCHECK_ALWAYS_ON everywhere

webrtc/base/checks.h

 /*
  *  Copyright 2006 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_BASE_CHECKS_H_
 #define WEBRTC_BASE_CHECKS_H_
 
 #include "webrtc/typedefs.h"
 
-#if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
+// If you for some reson need to know if DCHECKs are on, test the value of
+// RTC_DCHECK_IS_ON. (Test its value, not if it's defined; it'll always be
+// defined, to either a true or a false value.)
+#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
 #define RTC_DCHECK_IS_ON 1
 #else
 #define RTC_DCHECK_IS_ON 0
 #endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 NO_RETURN void rtc_FatalMessage(const char* file, int line, const char* msg);
 #ifdef __cplusplus
@@ skipping 56 matching lines @@
 // The actual stream used isn't important. We reference condition in the code
 // but don't evaluate it; this is to avoid "unused variable" warnings (we do so
 // in a particularly convoluted way with an extra ?: because that appears to be
 // the simplest construct that keeps Visual Studio from complaining about
 // condition being unused).
 #define RTC_EAT_STREAM_PARAMETERS(condition) \
   (true ? true : !(condition))               \
       ? static_cast<void>(0)                 \
       : rtc::FatalMessageVoidify() & rtc::FatalMessage("", 0).stream()
 
-// RTC_CHECK dies with a fatal error if condition is not true.  It is *not*
-// controlled by NDEBUG, so the check will be executed regardless of
-// compilation mode.
+// RTC_CHECK dies with a fatal error if condition is not true. It is *not*
+// controlled by NDEBUG or anything else, so the check will be executed
+// regardless of compilation mode.
 //
 // We make sure RTC_CHECK et al. always evaluates their arguments, as
 // doing RTC_CHECK(FunctionWithSideEffect()) is a common idiom.
 #define RTC_CHECK(condition)                                      \
   RTC_LAZY_STREAM(rtc::FatalMessage(__FILE__, __LINE__).stream(), \
                   !(condition))                                   \
       << "Check failed: " #condition << std::endl << "# "
 
 // Helper macro for binary operators.
 // Don't use this macro directly in your code, use RTC_CHECK_EQ et al below.
@@ skipping 164 matching lines @@
 #define RTC_DCHECK_EQ(a, b) RTC_DCHECK((a) == (b))
 #define RTC_DCHECK_NE(a, b) RTC_DCHECK((a) != (b))
 #define RTC_DCHECK_LE(a, b) RTC_DCHECK((a) <= (b))
 #define RTC_DCHECK_LT(a, b) RTC_DCHECK((a) < (b))
 #define RTC_DCHECK_GE(a, b) RTC_DCHECK((a) >= (b))
 #define RTC_DCHECK_GT(a, b) RTC_DCHECK((a) > (b))
 
 #endif  // __cplusplus
 
 #endif  // WEBRTC_BASE_CHECKS_H_