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

base/logging.h

 // 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_LOGGING_H_
 #define BASE_LOGGING_H_
 
 #include <cassert>
 #include <string>
 #include <cstring>
@@ skipping 635 matching lines @@
   LAZY_STREAM(LOG_STREAM(DCHECK), false)                                \
   << "Check failed: " #condition ". "
 
 #define DPCHECK(condition)                                              \
   __analysis_assume(!!(condition)),                                     \
   LAZY_STREAM(PLOG_STREAM(DCHECK), false)                               \
   << "Check failed: " #condition ". "
 
 #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_
 
 // Helper macro for binary operators.
 // Don't use this macro directly in your code, use DCHECK_EQ et al below.
 #define DCHECK_OP(name, op, val1, val2)                                   \
   if (DCHECK_IS_ON())                                                     \
     if (std::string* _result = logging::Check##name##Impl(                \
             (val1), (val2), #val1 " " #op " " #val2))                     \
@@ skipping 21 matching lines @@
 
 #define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2)
 #define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2)
 #define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2)
 #define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2)
 #define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2)
 #define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2)
 #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
 
 // Redefine the standard assert to use our nice log files
 #undef assert
 #define assert(x) DLOG_ASSERT(x)
 
 // This class more or less represents a particular log message.  You
 // create an instance of LogMessage and then stream stuff to it.
@@ skipping 211 matching lines @@
 #elif NOTIMPLEMENTED_POLICY == 5
 #define NOTIMPLEMENTED() do {\
   static bool logged_once = false;\
   LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
   logged_once = true;\
 } while(0);\
 EAT_STREAM_PARAMETERS
 #endif
 
 #endif  // BASE_LOGGING_H_