Fix definition order of ZScript structs

Do a first pass over the Structs array in CompileAllFields() to reorder them such that if a struct uses other structs, those structs will be resolved first.

src/common/scripting/core/types.cpp

@@ -334,6 +334,7 @@ void PType::StaticInit()
 	TypeVector2->moveOp = OP_MOVEV2;
 	TypeVector2->RegType = REGT_FLOAT;
 	TypeVector2->RegCount = 2;
+	TypeVector2->isOrdered = true;
 
 	TypeVector3 = new PStruct(NAME_Vector3, nullptr);
 	TypeVector3->AddField(NAME_X, TypeFloat64);
@@ -347,6 +348,7 @@ void PType::StaticInit()
 	TypeVector3->moveOp = OP_MOVEV3;
 	TypeVector3->RegType = REGT_FLOAT;
 	TypeVector3->RegCount = 3;
+	TypeVector3->isOrdered = true;
 
 
 	TypeFVector2 = new PStruct(NAME_FVector2, nullptr);
@@ -358,6 +360,7 @@ void PType::StaticInit()
 	TypeFVector2->moveOp = OP_MOVEV2;
 	TypeFVector2->RegType = REGT_FLOAT;
 	TypeFVector2->RegCount = 2;
+	TypeFVector2->isOrdered = true;
 
 	TypeFVector3 = new PStruct(NAME_FVector3, nullptr);
 	TypeFVector3->AddField(NAME_X, TypeFloat32);
@@ -371,6 +374,7 @@ void PType::StaticInit()
 	TypeFVector3->moveOp = OP_MOVEV3;
 	TypeFVector3->RegType = REGT_FLOAT;
 	TypeFVector3->RegCount = 3;
+	TypeFVector3->isOrdered = true;
 
 	Namespaces.GlobalNamespace->Symbols.AddSymbol(Create<PSymbolType>(NAME_sByte, TypeSInt8));
 	Namespaces.GlobalNamespace->Symbols.AddSymbol(Create<PSymbolType>(NAME_Byte, TypeUInt8));

src/common/scripting/core/types.h

@@ -537,6 +537,7 @@ public:
 	PStruct(FName name, PTypeBase *outer, bool isnative = false);
 
 	bool isNative;
+	bool isOrdered = false;
 	// Some internal structs require explicit construction and destruction of fields the VM cannot handle directly so use these two functions for it.
 	VMFunction *mConstructor = nullptr;
 	VMFunction *mDestructor = nullptr;

src/common/scripting/frontend/zcc_compile.cpp

@@ -1325,7 +1325,7 @@ void ZCCCompiler::CompileAllFields()
 {
 	// Create copies of the arrays which can be altered
 	auto Classes = this->Classes;
-	auto Structs = this->Structs;
+	auto Structs = OrderStructs();
 	TMap<FName, bool> HasNativeChildren;
 
 	// first step: Look for native classes with native children.
@@ -1612,6 +1612,83 @@ bool ZCCCompiler::CompileFields(PContainerType *type, TArray<ZCC_VarDeclarator *
 	return Fields.Size() == 0;
 }
 
+//==========================================================================
+//
+// ZCCCompiler :: OrderStructs
+//
+// Order the Structs array so that the least-dependant structs come first
+//
+//==========================================================================
+
+TArray<ZCC_StructWork *> ZCCCompiler::OrderStructs()
+{
+	TArray<ZCC_StructWork *> new_order;
+
+	for (auto struct_def : Structs)
+	{
+		if (std::find(new_order.begin(), new_order.end(), struct_def) != new_order.end())
+		{
+			continue;
+		}
+		AddStruct(new_order, struct_def);
+	}
+	return new_order;
+}
+
+//==========================================================================
+//
+// ZCCCompiler :: AddStruct
+//
+// Adds a struct to the Structs array, preceded by all its dependant structs
+//
+//==========================================================================
+
+void ZCCCompiler::AddStruct(TArray<ZCC_StructWork *> &new_order, ZCC_StructWork *my_def)
+{
+	PStruct *my_type = static_cast<PStruct *>(my_def->Type());
+	if (my_type)
+	{
+		if (my_type->isOrdered)
+		{
+			return;
+		}
+		my_type->isOrdered = true;
+	}
+
+	// Find all struct fields and add them before this one
+	for (const auto field : my_def->Fields)
+	{
+		PType *fieldtype = DetermineType(my_type, field, field->Names->Name, field->Type, true, true);
+		if (fieldtype->isStruct() && !static_cast<PStruct *>(fieldtype)->isOrdered)
+		{
+			AddStruct(new_order, StructTypeToWork(static_cast<PStruct *>(fieldtype)));
+		}
+	}
+	new_order.Push(my_def);
+}
+
+//==========================================================================
+//
+// ZCCCompiler :: StructTypeToWork
+//
+// Find the ZCC_StructWork that corresponds to a PStruct
+//
+//==========================================================================
+
+ZCC_StructWork *ZCCCompiler::StructTypeToWork(const PStruct *type) const
+{
+	assert(type->isStruct());
+	for (auto &def : Structs)
+	{
+		if (def->Type() == type)
+		{
+			return def;
+		}
+	}
+	assert(false && "Struct not found");
+	return nullptr;
+}
+
 //==========================================================================
 //
 // ZCCCompiler :: FieldFlagsToString

src/common/scripting/frontend/zcc_compile.h

@@ -135,6 +135,9 @@ protected:
 	PType *DetermineType(PType *outertype, ZCC_TreeNode *field, FName name, ZCC_Type *ztype, bool allowarraytypes, bool formember);
 	PType *ResolveArraySize(PType *baseType, ZCC_Expression *arraysize, PContainerType *cls, bool *nosize);
 	PType *ResolveUserType(ZCC_BasicType *type, PSymbolTable *sym, bool nativetype);
+	TArray<ZCC_StructWork *> OrderStructs();
+	void AddStruct(TArray<ZCC_StructWork *> &new_order, ZCC_StructWork *struct_def);
+	ZCC_StructWork *StructTypeToWork(const PStruct *type) const;
 
 	void CompileFunction(ZCC_StructWork *c, ZCC_FuncDeclarator *f, bool forclass);