Merge pull request #995 from anthofoxo/lua-hook

Provide Lua hook function for automatic Lua instrumentation.

manual/tracy.tex

@@ -2000,6 +2000,14 @@ Cost of performing Lua call stack capture is presented in table~\ref{CallstackTi
 
 Even if Tracy is disabled, you still have to pay the no-op function call cost. To prevent that, you may want to use the \texttt{tracy::LuaRemove(char* script)} function, which will replace instrumentation calls with white-space. This function does nothing if the profiler is enabled.
 
+\subsubsection{Automatic instrumentation}
+
+Lua code can be automatically instrumented by using Lua hooks. The \texttt{tracy::LuaHook(lua\_State*, lua\_Debug*)} function may be used as or within a Lua hook. There is a small performance impact from using Lua hooks since the Lua VM will be required to invoke the hook function.
+
+The Lua hook must have the \texttt{LUA\_HOOKCALL} and \texttt{LUA\_HOOKRET} event mask set. You may either directly set the function as your hook or chain it to your existing hook.
+
+Use \texttt{lua\_sethook(L, tracy::LuaHook, LUA\_MASKCALL | LUA\_MASKRET, 0)} if you do not already have a Lua hook set or directly call \texttt{tracy::LuaHook(L, ar)} within your hook if you already have one set.
+
 \subsection{C API}
 \label{capi}
 

public/tracy/TracyLua.hpp

@@ -120,6 +120,8 @@ static inline void LuaRemove( char* script )
     }
 }
 
+static inline void LuaHook( lua_State* L, lua_Debug* ar ) {}
+
 }
 
 #else
@@ -439,6 +441,44 @@ static inline void LuaRegister( lua_State* L )
 
 static inline void LuaRemove( char* script ) {}
 
+static inline void LuaHook( lua_State* L, lua_Debug* ar )
+{
+    if ( ar->event == LUA_HOOKCALL )
+    {
+#ifdef TRACY_ON_DEMAND
+        const auto zoneCnt = GetLuaZoneState().counter++;
+        if ( zoneCnt != 0 && !GetLuaZoneState().active ) return;
+        GetLuaZoneState().active = GetProfiler().IsConnected();
+        if ( !GetLuaZoneState().active ) return;
+#endif
+        lua_getinfo( L, "Snl", ar );
+
+        char src[256];
+        detail::LuaShortenSrc( src, ar->short_src );
+
+        const auto srcloc = Profiler::AllocSourceLocation( ar->currentline, src, ar->name ? ar->name : ar->short_src );
+        TracyQueuePrepare( QueueType::ZoneBeginAllocSrcLoc );
+        MemWrite( &item->zoneBegin.time, Profiler::GetTime() );
+        MemWrite( &item->zoneBegin.srcloc, srcloc );
+        TracyQueueCommit( zoneBeginThread );
+    }
+    else if (ar->event == LUA_HOOKRET) {
+#ifdef TRACY_ON_DEMAND
+        assert( GetLuaZoneState().counter != 0 );
+        GetLuaZoneState().counter--;
+        if ( !GetLuaZoneState().active ) return;
+        if ( !GetProfiler().IsConnected() )
+        {
+            GetLuaZoneState().active = false;
+            return;
+        }
+#endif
+        TracyQueuePrepare( QueueType::ZoneEnd );
+        MemWrite( &item->zoneEnd.time, Profiler::GetTime() );
+        TracyQueueCommit( zoneEndThread );
+    }
+}
+
 }
 
 #endif