@Override
public Type typecheck(SymTab s) {
Type varType = preDot.typecheck(s); // this must be a class type
// if it's another type throw an error
if (varType.getType() == "int" || varType.getType() == "bool" || varType.getType() == "empty") {
throw new Error(
line
+ ":"
+ column
+ " error: "
+ "used non-class variabe like a class (bad field access)");
}
classType = varType.getType();
/* Currently postDot is an ArrExpr that is kinda broken. Take example FieldExpr a.var, a:Point, var:int[]
* postDot currently has name as an IDExpr with name "var", but "var" isn't a variable
* Construct a new ArrExpr with postDot's accesses but prepend the classname, and typecheck it
*/
ArrExpr real =
new ArrExpr(
new IDExpr(varType.getType() + "." + postDot.getName().getName(), line, column),
postDot.getAccesses(),
postDot.getLine(),
postDot.getColumn());
// if this typechecks, the full FieldExpr is good
type = real.typecheck(s);
return type;
}
public IRExpr buildIRExpr() {
String _temp = LabelMaker.Generate_Unique_Label("_temp");
List<IRStmt> seqList = new ArrayList<IRStmt>();
seqList.add(new IRMove(new IRTemp(_temp), preDot.buildIRExpr()));
long offset =
(Compiler.DispachTable.get(classType).getFields().indexOf(postDot.getName().getName()) + 1)
* 8; // +1 for "this" pointer
seqList.add(
new IRMove(
new IRTemp(_temp),
new IRBinOp(IRBinOp.OpType.ADD, new IRTemp(_temp), new IRConst(offset))));
return new IRESeq(new IRSeq(seqList), new IRMem(new IRTemp(_temp)));
}