// *** 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
}
// NewArray ---
// int size;
public IrExp visit(AstNewArray n)
{
IrExp size = new IrConst(n.size);
IrStmtList sl = new IrStmtList();
IrName top = new IrName();
IrTemp array = new IrTemp();
IrTemp cnt = new IrTemp();
IrExp bound = new IrBinop(IrBinop.OP.MUL, new IrConst(n.size + 1), cWordSize);
sl.add(new IrMove(array, new IrCall(new IrName("malloc"), new IrExpList(bound))));
sl.add(new IrMove(new IrMem(array), size));
sl.add(new IrMove(cnt, new IrBinop(IrBinop.OP.ADD, array,
new IrBinop(IrBinop.OP.MUL, size, cWordSize))));
sl.add(new IrLabel(top));
sl.add(new IrMove(new IrMem(cnt), cZero));
sl.add(new IrMove(cnt, new IrBinop(IrBinop.OP.SUB, cnt, cWordSize)));
sl.add(new IrCJump(IrCJump.OP.GT, cnt, array, top));
return new IrEseq(sl, array);
}
/* 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(IrBinop e)
{
// evaluate both operands to lval and rval
int lval = e.left.accept(this);
int rval = e.right.accept(this);
// evaluate expression value
switch (e.op) {
case IrBinop.OP.ADD: return lval + rval;
case IrBinop.OP.SUB: return lval - rval;
case IrBinop.OP.MUL: return lval * rval;
case IrBinop.OP.DIV: return lval / rval;
case IrBinop.OP.AND: return (2 == (lval + rval)) ? 1 : 0;
case IrBinop.OP.OR: return (0 < (lval + rval)) ? 1 : 0;
default: throw new Exception("Encountered undefined BINOP value: " + e.op);
}
}
public IrExp visit(IrBinop t)
{
IrExp left = t.left.accept(this);
IrExp right = t.right.accept(this);
IrStmt s = mergeStmts(getStmt(left), getStmt(right));
if (s != null)
return new IrEseq(s, new IrBinop(t.op, getExp(left), getExp(right)));
return t;
}