- reverted most of the last commit after realizing that trying to manage constructing/destructing per variable is not going to work because it'd require some extensive exception management in the compiled VM code.

- instead add a list of SpecialInits to VMScriptFunction so this can be done transparently when setting up and popping the stack frame. The only drawback is that this requires permanent allocation of stack objects for the entire lifetime of a function but this is a relatively small tradeoff for significantly reduced maintenance work throughout.
- removed most #include "vm.h", because nearly all files already pull this in through dobject.h.

src/scripting/vm/vm.h

@@ -2,7 +2,6 @@
 #define VM_H
 
 #include "zstring.h"
-#include "dobject.h"
 #include "autosegs.h"
 #include "vectors.h"
 
@@ -815,6 +814,12 @@ public:
 	VM_UHALF MaxParam;		// Maximum number of parameters this function has on the stack at once
 	VM_UBYTE NumArgs;		// Number of arguments this function takes
 	FString PrintableName;	// so that the VM can print meaningful info if something in this function goes wrong.
+	TArray<FTypeAndOffset> SpecialInits;	// list of all contents on the extra stack which require construction and destruction
+
+	void InitExtra(void *addr);
+	void DestroyExtra(void *addr);
+	void SetExtraSpecial(PType *type, unsigned offset);
+	int AllocExtraStack(PType *type);
 };
 
 class VMFrameStack
@@ -822,7 +827,6 @@ class VMFrameStack
 public:
 	VMFrameStack();
 	~VMFrameStack();
-	VMFrame *AllocFrame(int numregd, int numregf, int numregs, int numrega);
 	VMFrame *AllocFrame(VMScriptFunction *func);
 	VMFrame *PopFrame();
 	VMFrame *TopFrame()

src/scripting/vm/vmbuilder.h

@@ -1,7 +1,7 @@
 #ifndef VMUTIL_H
 #define VMUTIL_H
 
-#include "vm.h"
+#include "dobject.h"
 
 class VMFunctionBuilder
 {

src/scripting/vm/vmdisasm.cpp

@@ -31,7 +31,7 @@
 **
 */
 
-#include "vm.h"
+#include "dobject.h"
 #include "c_console.h"
 #include "templates.h"
 

src/scripting/vm/vmexec.cpp

@@ -34,7 +34,7 @@
 #include <math.h>
 #include <v_video.h>
 #include <s_sound.h>
-#include "vm.h"
+#include "dobject.h"
 #include "xs_Float.h"
 #include "math/cmath.h"
 

src/scripting/vm/vmframe.cpp

@@ -32,7 +32,7 @@
 */
 
 #include <new>
-#include "vm.h"
+#include "dobject.h"
 
 IMPLEMENT_CLASS(VMException, false, false, false, false)
 IMPLEMENT_CLASS(VMFunction, true, true, false, false)
@@ -162,6 +162,38 @@ size_t VMScriptFunction::PropagateMark()
 	return NumKonstA * sizeof(void *) + Super::PropagateMark();
 }
 
+void VMScriptFunction::InitExtra(void *addr)
+{
+	char *caddr = (char*)addr;
+
+	for (auto tao : SpecialInits)
+	{
+		tao.first->InitializeValue(caddr + tao.second, nullptr);
+	}
+}
+
+void VMScriptFunction::DestroyExtra(void *addr)
+{
+	char *caddr = (char*)addr;
+
+	for (auto tao : SpecialInits)
+	{
+		tao.first->DestroyValue(caddr + tao.second);
+	}
+}
+
+void VMScriptFunction::SetExtraSpecial(PType *type, unsigned offset)
+{
+	type->SetDefaultValue(nullptr, offset, &SpecialInits);
+}
+
+int VMScriptFunction::AllocExtraStack(PType *type)
+{
+	int address = ((ExtraSpace + type->Align - 1) / type->Align) * type->Align;
+	ExtraSpace = address + type->Size;
+	return address;
+}
+
 //===========================================================================
 //
 // VMFrame :: InitRegS
@@ -223,34 +255,6 @@ VMFrameStack::~VMFrameStack()
 	UnusedBlocks = NULL;
 }
 
-//===========================================================================
-//
-// VMFrameStack :: AllocFrame
-//
-// Allocates a frame from the stack with the desired number of registers.
-//
-//===========================================================================
-
-VMFrame *VMFrameStack::AllocFrame(int numregd, int numregf, int numregs, int numrega)
-{
-	assert((unsigned)numregd < 255);
-	assert((unsigned)numregf < 255);
-	assert((unsigned)numregs < 255);
-	assert((unsigned)numrega < 255);
-	// To keep the arguments to this function simpler, it assumes that every
-	// register might be used as a parameter for a single call.
-	int numparam = numregd + numregf + numregs + numrega;
-	int size = VMFrame::FrameSize(numregd, numregf, numregs, numrega, numparam, 0);
-	VMFrame *frame = Alloc(size);
-	frame->NumRegD = numregd;
-	frame->NumRegF = numregf;
-	frame->NumRegS = numregs;
-	frame->NumRegA = numrega;
-	frame->MaxParam = numparam;
-	frame->InitRegS();
-	return frame;
-}
-
 //===========================================================================
 //
 // VMFrameStack :: AllocFrame
@@ -273,6 +277,10 @@ VMFrame *VMFrameStack::AllocFrame(VMScriptFunction *func)
 	frame->MaxParam = func->MaxParam;
 	frame->Func = func;
 	frame->InitRegS();
+	if (func->SpecialInits.Size())
+	{
+		func->InitExtra(frame->GetExtra());
+	}
 	return frame;
 }
 
@@ -358,6 +366,11 @@ VMFrame *VMFrameStack::PopFrame()
 	{
 		return NULL;
 	}
+	auto Func = static_cast<VMScriptFunction *>(frame->Func);
+	if (Func->SpecialInits.Size())
+	{
+		Func->DestroyExtra(frame->GetExtra());
+	}
 	// Free any string registers this frame had.
 	FString *regs = frame->GetRegS();
 	for (int i = frame->NumRegS; i != 0; --i)