- build full argument lists for action function calls.

This uses one static global array to avoid frequent reallocations.

src/info.cpp

@@ -155,6 +155,7 @@ void FState::CheckCallerType(AActor *self, AActor *stateowner)
 	}
 }
 
+TArray<VMValue> actionParams;
 
 bool FState::CallAction(AActor *self, AActor *stateowner, FStateParamInfo *info, FState **stateret)
 {
@@ -162,7 +163,6 @@ bool FState::CallAction(AActor *self, AActor *stateowner, FStateParamInfo *info,
 	{
 		ActionCycles.Clock();
 
-		VMValue params[3] = { self, stateowner, VMValue(info) };
 		// If the function returns a state, store it at *stateret.
 		// If it doesn't return a state but stateret is non-nullptr, we need
 		// to set *stateret to nullptr.
@@ -176,19 +176,36 @@ bool FState::CallAction(AActor *self, AActor *stateowner, FStateParamInfo *info,
 				stateret = nullptr;
 			}
 		}
+
+		VMReturn ret;
+		ret.PointerAt((void **)stateret);
 		try
 		{
 			CheckCallerType(self, stateowner);
 
-			if (stateret == nullptr)
+			// Build the parameter array. Action functions have never any explicit parameters but need to pass the defaults
+			// and fill in the implicit arguments of the called function.
+
+			if (ActionFunc->DefaultArgs.Size() > 0)
 			{
-				VMCallAction(ActionFunc, params, ActionFunc->ImplicitArgs, nullptr, 0);
+				auto index = actionParams.Append(ActionFunc->DefaultArgs);
+				if (ActionFunc->ImplicitArgs >= 1)
+				{
+					actionParams[index] = self;
+				}
+				if (ActionFunc->ImplicitArgs == 3)
+				{
+					actionParams[index + 1] = stateowner;
+					actionParams[index + 2] = VMValue(info);
+				}
+
+				VMCallAction(ActionFunc, &actionParams[index], ActionFunc->DefaultArgs.Size(), &ret, stateret != nullptr);
+				actionParams.Clamp(index);
 			}
 			else
 			{
-				VMReturn ret;
-				ret.PointerAt((void **)stateret);
-				VMCallAction(ActionFunc, params, ActionFunc->ImplicitArgs, &ret, 1);
+				VMValue params[3] = { self, stateowner, VMValue(info) };
+				VMCallAction(ActionFunc, params, ActionFunc->ImplicitArgs, &ret, stateret != nullptr);
 			}
 		}
 		catch (CVMAbortException &err)

src/p_actionfunctions.cpp

@@ -111,12 +111,13 @@ static FRandom pr_bfgselfdamage("BFGSelfDamage");
 // until there is no next state
 //
 //==========================================================================
+extern TArray<VMValue> actionParams;	// this can use the same storage as CallAction
+
 
 bool AStateProvider::CallStateChain (AActor *actor, FState *state)
 {
 	INTBOOL result = false;
 	int counter = 0;
-	VMValue params[3] = { actor, this, 0 };
 
 	// We accept return types of `state`, `(int|bool)` or `state, (int|bool)`.
 	// The last one is for the benefit of A_Warp and A_Teleport.
@@ -154,7 +155,6 @@ bool AStateProvider::CallStateChain (AActor *actor, FState *state)
 			VMReturn *wantret;
 			FStateParamInfo stp = { state, STATE_StateChain, PSP_WEAPON };
 
-			params[2] = VMValue(&stp);
 			retval = true;		// assume success
 			wantret = NULL;		// assume no return value wanted
 			numret = 0;
@@ -182,10 +182,33 @@ bool AStateProvider::CallStateChain (AActor *actor, FState *state)
 				wantret = &ret[1];
 				numret = 1;
 			}
+
+
 			try
 			{
                 state->CheckCallerType(actor, this);
-				VMCallAction(state->ActionFunc, params, state->ActionFunc->ImplicitArgs, wantret, numret);
+
+				if (state->ActionFunc->DefaultArgs.Size() > 0)
+				{
+					auto index = actionParams.Append(state->ActionFunc->DefaultArgs);
+					if (state->ActionFunc->ImplicitArgs >= 1)
+					{
+						actionParams[index] = actor;
+					}
+					if (state->ActionFunc->ImplicitArgs == 3)
+					{
+						actionParams[index + 1] = this;
+						actionParams[index + 2] = VMValue(&stp);
+					}
+
+					VMCallAction(state->ActionFunc, &actionParams[index], state->ActionFunc->DefaultArgs.Size(), wantret, numret);
+					actionParams.Clamp(index);
+				}
+				else
+				{
+					VMValue params[3] = { actor, this, VMValue(&stp) };
+					VMCallAction(state->ActionFunc, params, state->ActionFunc->ImplicitArgs, wantret, numret);
+				}
 			}
 			catch (CVMAbortException &err)
 			{

src/tarray.h

@@ -278,13 +278,30 @@ public:
 		return Count++;
 	}
 
-	void Append(const TArray<T> &item)
+	unsigned Append(const TArray<T> &item)
 	{
-		unsigned start = Reserve(item.Size());
+		unsigned start = Count;
+
+		Grow(item.Size());
+
 		for (unsigned i = 0; i < item.Size(); i++)
 		{
-			Array[start + i] = item[i];
+			new(&Array[start + i]) T(item[i]);
 		}
+		return start;
+	}
+
+	unsigned Append(TArray<T> &&item)
+	{
+		unsigned start = Count;
+
+		Grow(item.Size());
+
+		for (unsigned i = 0; i < item.Size(); i++)
+		{
+			new(&Array[start + i]) T(std::move(item[i]));
+		}
+		return start;
 	}
 
 	bool Pop ()