public bool VisitNode(ExpressionOnlyStatement node)
{
// expression;
Write("");
node.Value.AcceptVisitor(this);
return(true);
}
public CodeBody Decompile()
{
// Skip native funcs
var Func = DataContainer as ME3Function;
if (Func != null && Func.FunctionFlags.HasFlag(FunctionFlags.Native))
{
var comment = new ExpressionOnlyStatement(null, null, new SymbolReference(null, null, null, "// Native function"));
return(new CodeBody(new List <Statement>()
{
comment
}, null, null));
}
Position = 0;
_totalPadding = 0;
CurrentScope = new Stack <int>();
var statements = new List <Statement>();
StatementLocations = new Dictionary <UInt16, Statement>();
StartPositions = new Stack <UInt16>();
Scopes = new List <List <Statement> >();
LabelTable = new List <LabelTableEntry>();
ForEachScopes = new Stack <UInt16>();
DecompileDefaultParameterValues(statements);
Scopes.Add(statements);
CurrentScope.Push(Scopes.Count - 1);
while (Position < Size && !CurrentIs(StandardByteCodes.EndOfScript))
{
var current = DecompileStatement();
if (current == null && CurrentByte == (byte)StandardByteCodes.EndOfScript)
{
break; // Natural end after label table, no error
}
if (current == null)
{
break; // TODO: ERROR!
}
statements.Add(current);
}
CurrentScope.Pop();;
AddStateLabels();
return(new CodeBody(statements, null, null));
}
private void DecompileDefaultParameterValues(List <Statement> statements)
{
OptionalParams = new Stack <FunctionParameter>();
var func = DataContainer as ME3Function;
if (func != null) // Gets all optional params for default value parsing
{
for (int n = 0; n < Parameters.Count; n++)
{
if (func.Parameters[n].PropertyFlags.HasFlag(PropertyFlags.OptionalParm))
{
OptionalParams.Push(Parameters[n]);
}
}
}
while (CurrentByte == (byte)StandardByteCodes.DefaultParmValue ||
CurrentByte == (byte)StandardByteCodes.Nothing)
{
StartPositions.Push((UInt16)Position);
var token = PopByte();
if (token == (byte)StandardByteCodes.DefaultParmValue) // default value assigned
{
ReadInt16(); //MemSize of value
var value = DecompileExpression();
PopByte(); // end of value
var builder = new CodeBuilderVisitor(); // what a wonderful hack, TODO.
value.AcceptVisitor(builder);
if (OptionalParams.Count != 0)
{
var parm = OptionalParams.Pop();
parm.Variables.First().Name += " = " + builder.GetCodeString();
StartPositions.Pop();
}
else
{ // TODO: weird, research how to deal with this
var comment = new SymbolReference(null, null, null, "// Orphaned Default Parm: " + builder.GetCodeString());
var statement = new ExpressionOnlyStatement(null, null, comment);
StatementLocations.Add(StartPositions.Pop(), statement);
statements.Add(statement);
}
}
}
}
public Statement DecompileStatement()
{
StartPositions.Push((UInt16)Position);
var token = CurrentByte;
switch (token)
{
// return [expression];
case (byte)StandardByteCodes.Return:
return(DecompileReturn());
// switch (expression)
case (byte)StandardByteCodes.Switch:
return(DecompileSwitch());
// case expression :
case (byte)StandardByteCodes.Case:
return(DecompileCase());
// if (expression) // while / for / do until
case (byte)StandardByteCodes.JumpIfNot:
return(DecompileConditionalJump());
// continue
case (byte)StandardByteCodes.Jump: // TODO: UDK seems to compile this from break when inside ForEach, handle?
return(DecompileJump());
// continue (iterator)
case (byte)StandardByteCodes.IteratorNext:
PopByte(); // pop iteratornext token
return(DecompileJump());
// break;
case (byte)StandardByteCodes.IteratorPop:
return(DecompileIteratorPop());
// stop;
case (byte)StandardByteCodes.Stop:
PopByte();
var stopStatement = new StopStatement(null, null);
StatementLocations.Add(StartPositions.Pop(), stopStatement);
return(stopStatement);
// Goto label
case (byte)StandardByteCodes.GotoLabel:
PopByte();
var labelExpr = DecompileExpression();
var func = new SymbolReference(null, null, null, "goto");
var call = new FunctionCall(func, new List <Expression>()
{
labelExpr
}, null, null);
var gotoLabel = new ExpressionOnlyStatement(null, null, call);
StatementLocations.Add(StartPositions.Pop(), gotoLabel);
return(gotoLabel);
// assignable expression = expression;
case (byte)StandardByteCodes.Let:
case (byte)StandardByteCodes.LetBool:
case (byte)StandardByteCodes.LetDelegate:
return(DecompileAssign());
// [skip x bytes]
case (byte)StandardByteCodes.Skip: // TODO: this should never occur as statement, possibly remove?
PopByte();
ReadUInt16();
StartPositions.Pop();
return(DecompileStatement());
case (byte)StandardByteCodes.Nothing:
PopByte();
StartPositions.Pop();
return(DecompileStatement()); // TODO, should probably have a nothing expression or statement, this is ugly
// foreach IteratorFunction(...)
case (byte)StandardByteCodes.Iterator:
return(DecompileForEach());
// foreach arrayName(valuevariable[, indexvariable])
case (byte)StandardByteCodes.DynArrayIterator:
return(DecompileForEach(isDynArray: true));
case (byte)StandardByteCodes.LabelTable:
DecompileLabelTable();
StartPositions.Pop();
return(DecompileStatement());
#region unsupported
case (byte)StandardByteCodes.OptIfLocal: // TODO: verify, handle syntax
return(DecompileConditionalJump(isOpt: true));
case (byte)StandardByteCodes.OptIfInstance: // TODO: verify, handle syntax
return(DecompileConditionalJump(isOpt: true));
#endregion
default:
var expr = DecompileExpression();
if (expr != null)
{
var statement = new ExpressionOnlyStatement(null, null, expr);
StatementLocations.Add(StartPositions.Pop(), statement);
return(statement);
}
// ERROR!
break;
}
return(null);
}
public CodeBody Decompile()
{
// Skip native funcs
if (DataContainer is UFunction Func && Func.FunctionFlags.HasFlag(FunctionFlags.Native))
{
var comment = new ExpressionOnlyStatement(new SymbolReference(null, "// Native function"));
return(new CodeBody(new List <Statement> {
comment
}));
}
if (ContainingClass.Export.ObjectName == "SFXGalaxyMapObject")
{
//these functions are broken and cannot be decompiled. instead of trying, we construct a simpler, functionally identical version
if (DataContainer.Export.ObjectName == "GetEditorLabel")
{
return(new CodeBody(new List <Statement> {
new ReturnStatement(new SymbolReference(null, "sLabel"))
}));
}
if (DataContainer.Export.ObjectName == "InitializeAppearance")
{
return(new CodeBody(new List <Statement> {
new ReturnStatement()
}));
}
}
Position = 0;
_totalPadding = 0;
CurrentScope = new Stack <int>();
var statements = new List <Statement>();
StatementLocations = new Dictionary <ushort, Statement>();
StartPositions = new Stack <ushort>();
Scopes = new List <List <Statement> >();
LabelTable = new List <LabelTableEntry>();
ForEachScopes = new Stack <ushort>();
DecompileDefaultParameterValues(statements);
Scopes.Add(statements);
CurrentScope.Push(Scopes.Count - 1);
while (Position < Size && !CurrentIs(OpCodes.EndOfScript))
{
var current = DecompileStatement();
if (current == null && PeekByte == (byte)OpCodes.EndOfScript)
{
break; // Natural end after label table, no error
}
if (current == null)
{
//as well as being eye-catching in generated code, this is totally invalid unrealscript and will cause compilation errors!
statements.Clear();
statements.Add(new ExpressionOnlyStatement(new SymbolReference(null, "**************************")));
statements.Add(new ExpressionOnlyStatement(new SymbolReference(null, "* *")));
statements.Add(new ExpressionOnlyStatement(new SymbolReference(null, "* DECOMPILATION ERROR! *")));
statements.Add(new ExpressionOnlyStatement(new SymbolReference(null, "* *")));
statements.Add(new ExpressionOnlyStatement(new SymbolReference(null, "**************************")));
return(new CodeBody(statements));
}
statements.Add(current);
}
CurrentScope.Pop();
AddStateLabels();
Dictionary <Statement, ushort> LocationStatements = StatementLocations.ToDictionary(kvp => kvp.Value, kvp => kvp.Key);
DecompileLoopsAndIfs(statements, LocationStatements);
//a void return at the end of a function is a bytecode implementation detail, get rid of it.
//This will also get rid of returnnothings, so loop to make sure we get both
while (statements.Count > 0 && statements.Last() is ReturnStatement ret && ret.Value is null)
{
statements.RemoveAt(statements.Count - 1);
}
return(new CodeBody(statements));
}
public bool VisitNode(ExpressionOnlyStatement node)
{
throw new NotImplementedException();
}
public Statement DecompileStatement(ushort?startPosition = null)
{
StartPositions.Push(startPosition ?? (ushort)Position);
var token = PeekByte;
switch (token)
{
// return [expression];
case (byte)OpCodes.Return:
return(DecompileReturn());
// switch (expression)
case (byte)OpCodes.Switch:
return(DecompileSwitch());
// case expression :
case (byte)OpCodes.Case:
return(DecompileCase());
// if (expression) // while / for / do until
case (byte)OpCodes.JumpIfNot:
{
PopByte();
var jump = new IfNotJump(ReadUInt16(), DecompileExpression(), Position - StartPositions.Peek());
StatementLocations.Add(StartPositions.Pop(), jump);
return(jump);
}
case (byte)OpCodes.Jump:
{
PopByte();
ushort jumpLoc = ReadUInt16();
if (ForEachScopes.Count > 0 && jumpLoc == ForEachScopes.Peek())
{
var brk = new BreakStatement();
StatementLocations.Add(StartPositions.Pop(), brk);
return(brk);
}
var jump = new UnconditionalJump(jumpLoc);
StatementLocations.Add(StartPositions.Pop(), jump);
return(jump);
}
// continue (iterator)
case (byte)OpCodes.IteratorNext:
{
PopByte();
var itNext = new ContinueStatement();
StatementLocations.Add(StartPositions.Pop(), itNext);
if (PopByte() != (byte)OpCodes.Jump)
{
return(null); //there should always be a jump after an iteratornext that's not at the end of the loop
}
//skip the jump address
PopByte();
PopByte();
return(itNext);
}
// break;
case (byte)OpCodes.IteratorPop:
{
PopByte();
return(DecompileStatement(StartPositions.Pop()));
}
// stop;
case (byte)OpCodes.Stop:
PopByte();
var stopStatement = new StopStatement(null, null);
StatementLocations.Add(StartPositions.Pop(), stopStatement);
return(stopStatement);
// Goto label
case (byte)OpCodes.GotoLabel:
PopByte();
var gotoLabel = new StateGoto(DecompileExpression());
StatementLocations.Add(StartPositions.Pop(), gotoLabel);
return(gotoLabel);
// assignable expression = expression;
case (byte)OpCodes.Let:
case (byte)OpCodes.LetBool:
case (byte)OpCodes.LetDelegate:
return(DecompileAssign());
// [skip x bytes]
case (byte)OpCodes.Skip: // TODO: this should never occur as statement, possibly remove?
PopByte();
ReadUInt16();
StartPositions.Pop();
return(DecompileStatement());
case (byte)OpCodes.Nothing:
PopByte();
StartPositions.Pop();
return(DecompileStatement()); // TODO, should probably have a nothing expression or statement, this is ugly
// foreach IteratorFunction(...)
case (byte)OpCodes.Iterator:
return(DecompileForEach());
// foreach arrayName(valuevariable[, indexvariable])
case (byte)OpCodes.DynArrayIterator:
return(DecompileForEach(true));
case (byte)OpCodes.LabelTable:
DecompileLabelTable();
StartPositions.Pop();
return(DecompileStatement());
case (byte)OpCodes.OptIfLocal:
case (byte)OpCodes.OptIfInstance:
{
PopByte();
IEntry obj = ReadObject();
var condition = new SymbolReference(null, obj.ObjectName.Instanced);
bool not = Convert.ToBoolean(ReadByte());
if (obj.ClassName == "BoolProperty")
{
var ifJump = new IfNotJump(
ReadUInt16(), not ? (Expression)condition : new PreOpReference(new PreOpDeclaration("!", SymbolTable.BoolType, 0, null), condition),
Position - StartPositions.Peek());
StatementLocations.Add(StartPositions.Pop(), ifJump);
return(ifJump);
}
var nullJump = new NullJump(ReadUInt16(), condition, not)
{
SizeOfExpression = Position - StartPositions.Peek()
};
StatementLocations.Add(StartPositions.Pop(), nullJump);
return(nullJump);
}
case (byte)OpCodes.FilterEditorOnly:
{
PopByte();
var edFilter = new InEditorJump(ReadUInt16());
StatementLocations.Add(StartPositions.Pop(), edFilter);
return(edFilter);
}
case (byte)OpCodes.EatReturnValue:
PopByte();
ReadObject();
return(DecompileStatement(StartPositions.Pop()));
case (byte)OpCodes.Assert:
return(DecompileAssert());
default:
var expr = DecompileExpression();
if (expr != null)
{
var statement = new ExpressionOnlyStatement(expr, null, null);
StatementLocations.Add(StartPositions.Pop(), statement);
return(statement);
}
// ERROR!
return(null);
}
}
