DRTVWR-559: Replace debugLoggingEnabled() function with LL_DEBUGS().

The trouble with debugLoggingEnabled() is that it locked mutexes and searched
maps every time that call was reached. LL_DEBUGS() has the same functionality
(albeit with idiosyncratic syntax) but performs expensive lookups only once
per session, caching the result in a local static variable.

3 files changed, 29 insertions, 21 deletions

diff --git a/indra/llcommon/llcallstack.h b/indra/llcommon/llcallstack.h
index 5acf04a49f..d5a2b7b157 100644
--- a/indra/llcommon/llcallstack.h
+++ b/indra/llcommon/llcallstack.h
@@ -79,9 +79,9 @@ struct LLContextStatus
 
 LL_COMMON_API std::ostream& operator<<(std::ostream& s, const LLContextStatus& context_status);
 
-#define dumpStack(tag) \
-    if (debugLoggingEnabled(tag)) \
-    { \
-        LLCallStack cs; \
-        LL_DEBUGS(tag) << "STACK:\n" << "====================\n" << cs << "====================" << LL_ENDL; \
-    }
+#define dumpStack(tag)                          \
+    LL_DEBUGS(tag) << "STACK:\n"                \
+                   << "====================\n"  \
+                   << LLCallStack()             \
+                   << "===================="    \
+                   << LL_ENDL;
diff --git a/indra/llcommon/llerror.cpp b/indra/llcommon/llerror.cpp
index 56fb7c21ca..5aa8558878 100644
--- a/indra/llcommon/llerror.cpp
+++ b/indra/llcommon/llerror.cpp
@@ -1609,19 +1609,5 @@ namespace LLError
     }
 }
 
-bool debugLoggingEnabled(const std::string& tag)
-{
-    LLMutexTrylock lock(getMutex<LOG_MUTEX>(), 5);
-    if (!lock.isLocked())
-    {
-        return false;
-    }
-
-    SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
-    LLError::ELevel level = LLError::LEVEL_DEBUG;
-    bool res = checkLevelMap(s->mTagLevelMap, tag, level);
-    return res;
-}
-
 
 
diff --git a/indra/llcommon/llerror.h b/indra/llcommon/llerror.h
index b7dec3cb7f..08eb323c4a 100644
--- a/indra/llcommon/llerror.h
+++ b/indra/llcommon/llerror.h
@@ -467,7 +467,29 @@ typedef LLError::NoClassInfo _LL_CLASS_TO_LOG;
 		LLError::CallSite& _site(_sites[which]);                        \
 		lllog_test_()
 
-// Check at run-time whether logging is enabled, without generating output
+/*
+// Check at run-time whether logging is enabled, without generating output.
+Resist the temptation to add a function like this because it incurs the
+expense of locking and map-searching every time control reaches it.
 bool debugLoggingEnabled(const std::string& tag);
 
+Instead of:
+
+if debugLoggingEnabled("SomeTag")
+{
+    // ... presumably expensive operation ...
+    LL_DEBUGS("SomeTag") << ... << LL_ENDL;
+}
+
+Use this:
+
+LL_DEBUGS("SomeTag");
+// ... presumably expensive operation ...
+LL_CONT << ...;
+LL_ENDL;
+
+LL_DEBUGS("SomeTag") performs the locking and map-searching ONCE, then caches
+the result in a static variable.
+*/ 
+
 #endif // LL_LLERROR_H