diff --git a/src/scripting/backend/vmbuilder.cpp b/src/scripting/backend/vmbuilder.cpp
index 4ed4f5c4e..e4682432c 100644
--- a/src/scripting/backend/vmbuilder.cpp
+++ b/src/scripting/backend/vmbuilder.cpp
@@ -139,6 +139,7 @@ void VMFunctionBuilder::MakeFunction(VMScriptFunction *func)
 	func->NumRegA = Registers[REGT_POINTER].MostUsed;
 	func->NumRegS = Registers[REGT_STRING].MostUsed;
 	func->MaxParam = MaxParam;
+	func->StackSize = VMFrame::FrameSize(func->NumRegD, func->NumRegF, func->NumRegS, func->NumRegA, func->MaxParam, func->ExtraSpace);
 
 	// Technically, there's no reason why we can't end the function with
 	// entries on the parameter stack, but it means the caller probably
diff --git a/src/scripting/vm/vm.h b/src/scripting/vm/vm.h
index 42558da09..b95be74e3 100644
--- a/src/scripting/vm/vm.h
+++ b/src/scripting/vm/vm.h
@@ -716,6 +716,7 @@ public:
 	int ExtraSpace;
 	int CodeSize;			// Size of code in instructions (not bytes)
 	unsigned LineInfoCount;
+	unsigned StackSize;
 	VM_UBYTE NumRegD;
 	VM_UBYTE NumRegF;
 	VM_UBYTE NumRegS;
diff --git a/src/scripting/vm/vmframe.cpp b/src/scripting/vm/vmframe.cpp
index e2ec3865a..4a0a2538a 100644
--- a/src/scripting/vm/vmframe.cpp
+++ b/src/scripting/vm/vmframe.cpp
@@ -273,10 +273,8 @@ VMFrameStack::~VMFrameStack()
 
 VMFrame *VMFrameStack::AllocFrame(VMScriptFunction *func)
 {
-	int size = VMFrame::FrameSize(func->NumRegD, func->NumRegF, func->NumRegS, func->NumRegA,
-		func->MaxParam, func->ExtraSpace);
-	VMFrame *frame = Alloc(size);
 	frame->Func = func;
+	VMFrame *frame = Alloc(func->StackSize);
 	frame->NumRegD = func->NumRegD;
 	frame->NumRegF = func->NumRegF;
 	frame->NumRegS = func->NumRegS;