- scriptified PowerProtection and PowerDamage.

- made ModifyDamage calls iterative instead of recursive. With going through the VM they'd be too costly otherwise.
- small optimization: Detect empty VM functions right when entering the VM and shortcut them. This is to reduce the overhead of virtual placeholders, which in a few cases (e.g. CanCollideWith and ModifyDamage) can be called quite frequently.

src/scripting/vm/vmframe.cpp

@@ -467,15 +467,30 @@ int VMFrameStack::Call(VMFunction *func, VMValue *params, int numparams, VMRetur
 		}
 		else
 		{
-			VMCycles[0].Clock();
-			VMCalls[0]++;
-			AllocFrame(static_cast<VMScriptFunction *>(func));
-			allocated = true;
-			VMFillParams(params, TopFrame(), numparams);
-			int numret = VMExec(this, static_cast<VMScriptFunction *>(func)->Code, results, numresults);
-			PopFrame();
-			VMCycles[0].Unclock();
-			return numret;
+			auto code = static_cast<VMScriptFunction *>(func)->Code;
+			// handle empty functions consisting of a single return explicitly so that empty virtual callbacks do not need to set up an entire VM frame.
+			if (code->word == 0x0080804e)
+			{
+				return 0;
+			}
+			else if (code->word == 0x0004804e)
+			{
+				if (numresults == 0) return 0;
+				results[0].SetInt(static_cast<VMScriptFunction *>(func)->KonstD[0]);
+				return 1;
+			}
+			else
+			{
+				VMCycles[0].Clock();
+				VMCalls[0]++;
+				AllocFrame(static_cast<VMScriptFunction *>(func));
+				allocated = true;
+				VMFillParams(params, TopFrame(), numparams);
+				int numret = VMExec(this, code, results, numresults);
+				PopFrame();
+				VMCycles[0].Unclock();
+				return numret;
+			}
 		}
 	}
 	catch (VMException *exception)