Make a new TRACE macro that is slower but uses less memory

The current TRACE macros are designed for speed but it means
they generate lots of code. I added a 
TRACE_EVENT_BINARY_EFFICENTx for those cases
where memory is more important the speed. 

The issue here is I'm auto generating traces. The normal
TRACE_EVENT0 ended up adding 90k+ to the release build.
This new macro does not. This won't effect perf because
these macros used through a wrapper that only gets used 
when certain command line flags are passed in.

In other words the code that uses these macros is not 
called without the command line flags.

BUG=176383


Review URL: https://chromiumcodereview.appspot.com/12278018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182993 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 74 insertions, 0 deletions

diff --git a/base/debug/trace_event_impl.cc b/base/debug/trace_event_impl.cc
index 3c770c3..cbcf54b 100644
--- a/base/debug/trace_event_impl.cc
+++ b/base/debug/trace_event_impl.cc
@@ -821,3 +821,51 @@ void TraceLog::SetTimeOffset(TimeDelta offset) {
 
 }  // namespace debug
 }  // namespace base
+
+namespace trace_event_internal {
+
+ScopedTrace::ScopedTrace(
+    TRACE_EVENT_API_ATOMIC_WORD* event_uid, const char* name) {
+  category_enabled_ =
+    reinterpret_cast<const unsigned char*>(TRACE_EVENT_API_ATOMIC_LOAD(
+        *event_uid));
+  if (!category_enabled_) {
+    category_enabled_ = TRACE_EVENT_API_GET_CATEGORY_ENABLED("gpu");
+    TRACE_EVENT_API_ATOMIC_STORE(
+        *event_uid,
+        reinterpret_cast<TRACE_EVENT_API_ATOMIC_WORD>(category_enabled_));
+  }
+  if (*category_enabled_) {
+    name_ = name;
+    TRACE_EVENT_API_ADD_TRACE_EVENT(
+        TRACE_EVENT_PHASE_BEGIN,    // phase
+        category_enabled_,          // category enabled
+        name,                       // name
+        0,                          // id
+        0,                          // num_args
+        NULL,                       // arg_names
+        NULL,                       // arg_types
+        NULL,                       // arg_values
+        TRACE_EVENT_FLAG_NONE);     // flags
+  } else {
+    category_enabled_ = NULL;
+  }
+}
+
+ScopedTrace::~ScopedTrace() {
+  if (category_enabled_ && *category_enabled_) {
+    TRACE_EVENT_API_ADD_TRACE_EVENT(
+        TRACE_EVENT_PHASE_END,   // phase
+        category_enabled_,       // category enabled
+        name_,                   // name
+        0,                       // id
+        0,                       // num_args
+        NULL,                    // arg_names
+        NULL,                    // arg_types
+        NULL,                    // arg_values
+        TRACE_EVENT_FLAG_NONE);  // flags
+  }
+}
+
+}  // namespace trace_event_internal
+
diff --git a/base/debug/trace_event_internal.h b/base/debug/trace_event_internal.h
index 7cd56d0..2cdbe68 100644
--- a/base/debug/trace_event_internal.h
+++ b/base/debug/trace_event_internal.h
@@ -991,6 +991,32 @@ class TRACE_EVENT_API_CLASS_EXPORT TraceEndOnScopeClose {
   Data data_;
 };
 
+// Used by TRACE_EVENT_BINARY_EFFICIENTx macro. Do not use directly.
+class TRACE_EVENT_API_CLASS_EXPORT ScopedTrace {
+ public:
+  ScopedTrace(TRACE_EVENT_API_ATOMIC_WORD* event_uid, const char* name);
+  ~ScopedTrace();
+
+ private:
+  const unsigned char* category_enabled_;
+  const char* name_;
+};
+
+// A support macro for TRACE_EVENT_BINARY_EFFICIENTx
+#define INTERNAL_TRACE_EVENT_BINARY_EFFICIENT_ADD_SCOPED( \
+    category, name, ...) \
+    static TRACE_EVENT_API_ATOMIC_WORD INTERNAL_TRACE_EVENT_UID(atomic) = 0; \
+    trace_event_internal::ScopedTrace \
+        INTERNAL_TRACE_EVENT_UID(profileScope)( \
+            &INTERNAL_TRACE_EVENT_UID(atomic), name); \
+
+// This macro generates less code then TRACE_EVENT0 but is also
+// slower to execute when tracing is off. It should generally only be
+// used with code that is seldom executed or conditionally executed
+// when debugging.
+#define TRACE_EVENT_BINARY_EFFICIENT0(category, name) \
+    INTERNAL_TRACE_EVENT_BINARY_EFFICIENT_ADD_SCOPED(category, name)
+
 }  // namespace trace_event_internal
 
 #endif  // BASE_DEBUG_TRACE_EVENT_INTERNAL_H_