// *** partial implementation, will be fixed in proj2 ****
// NewObj ---
// Id cid;
public IrExp visit(AstNewObj n)
{
// A NewObj node should be translated into a CALL to "malloc" with a single argument representing the size
// of the object, followed by a sequence of statements for initializing the object’s class variables.
// A special note: the initialization expressions saved in the the symbol table entry for this purpose are
// AST expressions, and need to be translated into IR expressions. Furthermore, this translation should be
// conducted in the proper scope environment — the IrgenVisitor variable currClass needs to point to the
// object’s class.
IrStmtList stmts = new IrStmtList();
// Calculate the size of the object
ClassRec classRec = symTable.GetClass(n.cid); // <get the object's ClassRec from symbol table>;
int numVars = GetNumObjVars(classRec);
// Construct malloc call node
IrExp size = new IrBinop(IrBinop.OP.MUL, new IrConst(numVars > 0 ? numVars : 1), cWordSize);
IrCall call = new IrCall(new IrName("malloc"), new IrExpList(size));
IrTemp tmp = new IrTemp(); // This TEMP will contain the location of the object variables
stmts.add(new IrMove(tmp, call)); // Move the results of the malloc call into the temp
GetInitStmts(classRec, stmts, tmp); // Recursively get object's variable initialization statements
return new IrEseq(stmts, tmp); // Construct resulting statement
}
/* throws ParseException */
public static IrExp EXP()
{
IrToken t;
int n;
String str;
IrStmt s;
IrExp e, e2;
IrExpList el = new IrExpList();
jj_consume_token(RegExpId.kw32);
switch ((jj_ntk == RegExpId.UNDEFINED) ? jj_ntk_fn() : jj_ntk)
{
case RegExpId.kwESEQ:
jj_consume_token(RegExpId.kwESEQ);
s = STMT();
e = EXP();
e = new IrEseq(s,e);
break;
case RegExpId.kwMEM:
jj_consume_token(RegExpId.kwMEM);
e = EXP();
e = new IrMem(e);
break;
case RegExpId.kwBINOP:
jj_consume_token(RegExpId.kwBINOP);
IrBinop.OP op = binopCode();
e = EXP();
e2 = EXP();
e = new IrBinop(op,e,e2);
break;
case RegExpId.kwCALL:
jj_consume_token(RegExpId.kwCALL);
e = EXP();
jj_consume_token(RegExpId.kw32);
// label_4:
while (true)
{
switch ((jj_ntk == RegExpId.UNDEFINED) ? jj_ntk_fn() : jj_ntk)
{
case RegExpId.kw32:
break;
default:
jj_la1[7] = jj_gen;
goto label_4a; // break label_4;
}
e2 = EXP();
el.add(e2);
}
label_4a:
jj_consume_token(RegExpId.kw35);
e = new IrCall((IrName)e,el);
break;
case RegExpId.kwTEMP:
jj_consume_token(RegExpId.kwTEMP);
n = INT();
e = new IrTemp(n);
break;
case RegExpId.kwNAME:
jj_consume_token(RegExpId.kwNAME);
t = jj_consume_token(RegExpId.ID);
e = new IrName(t.image);
break;
case RegExpId.kwFIELD:
jj_consume_token(RegExpId.kwFIELD);
e = EXP();
n = INT();
e = new IrField(e,n);
break;
case RegExpId.kwPARAM:
jj_consume_token(RegExpId.kwPARAM);
n = INT();
e = new IrParam(n);
break;
case RegExpId.kwVAR:
jj_consume_token(RegExpId.kwVAR);
n = INT();
e = new IrVar(n);
break;
case RegExpId.kwCONST:
jj_consume_token(RegExpId.kwCONST);
n = INT();
e = new IrConst(n);
break;
case RegExpId.kwSTRING:
jj_consume_token(RegExpId.kwSTRING);
str = STR();
e = new IrString(str);
break;
default:
jj_la1[8] = jj_gen;
jj_consume_token(RegExpId.UNDEFINED);
throw new IrParseException();
}
jj_consume_token(RegExpId.kw35);
{if (true) return e;}
throw new Error("Missing return statement in function");
}
public int visit(IrCall s)
{
if (s.func.id.Equals("malloc")) {
IrExp arg0 = s.args.elementAt(0);
int val = arg0.accept(this);
hp -= val;
retVal=hp;
} else {
//– find the FUNC node corresponding to the routine from the program’s funcs list, and switch there
IrFunc func = findFunc(s.func.id);
//push parameters onto the stack (at stack[sp+1], stack[sp+2], etc.);
for (int i = 0; i < s.args.size(); ++i) {
stack[sp + i + 1] = s.args.elementAt(i).accept(this);
}
// adjust the frame pointer (save the current fp in stack[sp], and set sp to be the new fp);
stack[sp] = fp;
fp = sp;
//to execute (by invoking accept() on the FUNC node);
func.accept(this);
// After control returns, restore the saved frame pointer.
sp = fp;
fp = stack[sp];
}
return retVal;
}
public IrExp visit(IrCall t)
{
IrExp args = t.args.accept(this);
IrStmt s = getStmt(args);
if (t.func.id != "malloc")
{
IrTemp tmp = new IrTemp();
IrStmt s1 = new IrMove(tmp, new IrCall(t.func, (IrExpList)getExp(args)));
return new IrEseq(mergeStmts(s, s1), tmp);
}
else if (s != null)
{
return new IrEseq(s, new IrCall(t.func, (IrExpList)getExp(args)));
}
else
{
return t;
}
}