Make GPU_DCHECK* keep reference to passed variables

gpu/command_buffer/common/logging.h

 // 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 GPU_COMMAND_BUFFER_COMMON_LOGGING_H_
 #define GPU_COMMAND_BUFFER_COMMON_LOGGING_H_
 
 #include <assert.h>
 
 #include <ostream>
@@ skipping 138 matching lines @@
  private:
   Logger(const Logger& logger)
       : condition_(logger.condition_),
         level_(logger.level_) {
   }
 
   const bool condition_;
   const LogLevel level_;
 };
 
-// This is a logger that does not do anything for release builds.
-class NoLogger {
- public:
-  template <typename T>
-  NoLogger& operator<<(const T& value) {
-    return *this;
-  }
-};
-
 }  // namespace gpu
 
 #define GPU_CHECK(X) ::gpu::Logger::CheckTrue( \
     (X), __FILE__, __LINE__, #X, "GPU_CHECK")
 #define GPU_CHECK_EQ(X, Y) ::gpu::Logger::CheckEqual( \
     (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_CHECK_EQ")
 #define GPU_CHECK_NE(X, Y) ::gpu::Logger::CheckNotEqual( \
     (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_CHECK_NE")
 #define GPU_CHECK_GT(X, Y) ::gpu::Logger::CheckGreaterThan( \
     (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_CHECK_GT")
 #define GPU_CHECK_LT(X, Y) ::gpu::Logger::CheckLessThan( \
     (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_CHECK_LT")
 #define GPU_CHECK_GE(X, Y) ::gpu::Logger::CheckGreaterEqual( \
     (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_CHECK_GE")
 #define GPU_CHECK_LE(X, Y) ::gpu::Logger::CheckLessEqual( \
     (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_CHECK_LE")
 #define GPU_LOG(LEVEL) ::gpu::Logger(false, LEVEL)
 
+
 #if defined(NDEBUG)
+#define GPU_DEBUG_IS_ON() false

[apatrick_chromium, 2011/10/13 18:14:13]

This could just be:

#define GPU_DEBUG_IS_ON false

because the macro takes no parameters.

+#else
+#define GPU_DEBUG_IS_ON() true
+#endif
 
-#define GPU_DCHECK(X) ::gpu::NoLogger()
-#define GPU_DCHECK_EQ(X, Y) ::gpu::NoLogger()
-#define GPU_DCHECK_NE(X, Y) ::gpu::NoLogger()
-#define GPU_DCHECK_GT(X, Y) ::gpu::NoLogger()
-#define GPU_DCHECK_LT(X, Y) ::gpu::NoLogger()
-#define GPU_DCHECK_GE(X, Y) ::gpu::NoLogger()
-#define GPU_DCHECK_LE(X, Y) ::gpu::NoLogger()
-#define GPU_DLOG(LEVEL) ::gpu::NoLogger()
 
-#else  // NDEBUG
+#define GPU_DCHECK(X) \
+  if(GPU_DEBUG_IS_ON()) \

[apatrick_chromium, 2011/10/13 18:14:13]

Chromium code style would be:

if (GPU_DEBUG_IS_ON()) \
  ::gpu::Logger::CheckTrue( \
      (X), __FILE__, __LINE__, #X, "GPU_DCHECK")

Note the extra two spaces of indentation in front of "(X)" and the space after
the "if".

But it won't work in all cases. Example:

if (foo)
  GPU_DCHECK(bar > 0);
else
  GPU_DCHECK(bar < 0);

With this change, the "else" would be paired with the "if(GPU_DEBUG_IS_ON())" in
the expanded GPU_DCHECK macro instead of the "if (foo)".

Lastly, have you verified that the compiler does not generate any extra code for
these macros when GPU_DEBUG_IS_ON is false and the optimizer is enabled?

+    ::gpu::Logger::CheckTrue( \
+      (X), __FILE__, __LINE__, #X, "GPU_DCHECK")
+#define GPU_DCHECK_EQ(X, Y) \
+  if(GPU_DEBUG_IS_ON()) \
+    ::gpu::Logger::CheckEqual( \
+        (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_EQ")
+#define GPU_DCHECK_NE(X, Y) \
+  if(GPU_DEBUG_IS_ON()) \
+    ::gpu::Logger::CheckNotEqual( \
+      (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_NE")
+#define GPU_DCHECK_GT(X, Y) \
+  if(GPU_DEBUG_IS_ON()) \
+    ::gpu::Logger::CheckGreaterThan( \
+      (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_GT")
+#define GPU_DCHECK_LT(X, Y) \
+  if(GPU_DEBUG_IS_ON()) \
+    ::gpu::Logger::CheckLessThan( \
+      (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_LT")
+#define GPU_DCHECK_GE(X, Y) \
+  if(GPU_DEBUG_IS_ON()) \
+    ::gpu::Logger::CheckGreaterEqual( \
+      (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_GE")
+#define GPU_DCHECK_LE(X, Y) \
+  if(GPU_DEBUG_IS_ON()) \
+    ::gpu::Logger::CheckLessEqual( \
+      (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_LE")
+#define GPU_DLOG(LEVEL) if(GPU_DEBUG_IS_ON()) ::gpu::Logger(true, LEVEL)
 
-#define GPU_DCHECK(X) ::gpu::Logger::CheckTrue( \
-    (X), __FILE__, __LINE__, #X, "GPU_DCHECK")
-#define GPU_DCHECK_EQ(X, Y) ::gpu::Logger::CheckEqual( \
-    (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_EQ")
-#define GPU_DCHECK_NE(X, Y) ::gpu::Logger::CheckNotEqual( \
-    (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_NE")
-#define GPU_DCHECK_GT(X, Y) ::gpu::Logger::CheckGreaterThan( \
-    (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_GT")
-#define GPU_DCHECK_LT(X, Y) ::gpu::Logger::CheckLessThan( \
-    (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_LT")
-#define GPU_DCHECK_GE(X, Y) ::gpu::Logger::CheckGreaterEqual( \
-    (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_GE")
-#define GPU_DCHECK_LE(X, Y) ::gpu::Logger::CheckLessEqual( \
-    (X), (Y), __FILE__, __LINE__, #X, #Y, "GPU_DCHECK_LE")
-#define GPU_DLOG(LEVEL) ::gpu::Logger(true, LEVEL)
 
-#endif  // NDEBUG
 
 #define GPU_NOTREACHED() GPU_DCHECK(false)
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_LOGGING_H_