Chrome OS: Reduce NOTREACHED() overhead for release builds.

base/logging.h

Index: base/logging.h
diff --git a/base/logging.h b/base/logging.h
index cc0a5aa11bc4de78eaf868d1af2e289236baf4f1..cc341f97c4a601154eaffc5e0a86c475161f9116 100644
--- a/base/logging.h
+++ b/base/logging.h
@@ -653,12 +653,12 @@ const LogSeverity LOG_DCHECK = LOG_INFO;
 
 #else  // _PREFAST_
 
-#define DCHECK(condition)                                                \
-  LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \
+#define DCHECK(condition)                                         \
+  LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON() && !(condition)) \

[danakj, 2015/05/04 18:21:46]

This is unrelated, please don't lump multiple logical changes into one CL.

[Thiemo Nagel, 2015/05/04 19:15:47]

Done.

       << "Check failed: " #condition ". "
 
-#define DPCHECK(condition)                                                \
-  LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \
+#define DPCHECK(condition)                                         \
+  LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON() && !(condition)) \
       << "Check failed: " #condition ". "
 
 #endif  // _PREFAST_
@@ -700,8 +700,12 @@ const LogSeverity LOG_DCHECK = LOG_INFO;
 #define DCHECK_IMPLIES(val1, val2) DCHECK(!(val1) || (val2))
 
 #if !DCHECK_IS_ON() && defined(OS_CHROMEOS)
-#define NOTREACHED() LOG(ERROR) << "NOTREACHED() hit in " << \
-    __FUNCTION__ << ". "
+// Implement logging of NOTREACHED() as a dedicated function to get function
+// call overhead down to a minimum.
+void LogErrorNotReached(const char* file, int line, const char* function_name);
+#define NOTREACHED()                                                     \
+  true ? ::logging::LogErrorNotReached(__FILE__, __LINE__, __FUNCTION__) \

[danakj, 2015/05/04 18:27:41]

what's the point of the ternary that's always true?

[Thiemo Nagel, 2015/05/04 19:15:47]

The ternary is used as a binder so that EAT_STREAM_PARAMETERS can be attached as
part of the same, single statement.  Using two statements would break use cases
such as "if (cond) NOTREACHED(); else blah();".

+       : EAT_STREAM_PARAMETERS
 #else
 #define NOTREACHED() DCHECK(false)
 #endif