//Extractors
static T_exp unEx(Tr_exp e){
Temp_temp r;
Temp_label t,f;
T_exp ex;
switch(e->kind){
case Tr_ex:
ex = e->u.ex;
break;
case Tr_cx:
r = Temp_newtemp();
t = Temp_newlabel();
f = Temp_newlabel();
doPatch(e->u.cx.trues, t);
doPatch(e->u.cx.falses, f);
ex = T_Eseq(T_Move(T_Temp(r), T_Const(1)),
T_Eseq(e->u.cx.stm,
T_Eseq(T_Label(f),
T_Eseq(T_Move(T_Temp(r), T_Const(0)),
T_Eseq(T_Label(t),
T_Temp(r)
)
)
)
)
);
break;
case Tr_nx:
ex = T_Eseq(e->u.nx, T_Const(0));
break;
}
return ex;
}
Tr_exp Tr_forExp(Tr_exp var, Tr_exp low, Tr_exp high, Tr_exp body){
debug("Tr_forExp");
T_stm st;
T_exp v = unEx(var);
Temp_label t = Temp_newlabel();
Temp_label f = LL_peek();//Get done label from the list, which should have been prepared before this function is called.
Temp_label start = Temp_newlabel();
T_stm cond = T_Cjump(T_le, v, unEx(high), t, f);
/*
T_Move var <- low
T_Label start
T_CJump var <= high, t, f
T_Label(t)
body
T_Move var + 1
T_Jump start
T_Label(f)
*/
st = T_Seq(T_Move(v, unEx(low)),
T_Seq(T_Label(start),
T_Seq(cond,
T_Seq(T_Label(t),
T_Seq(unNx(body),
T_Seq(T_Move(v, T_Binop(T_plus, v, T_Const(1))),
T_Seq(
T_Jump(
T_Name(start),
Temp_LabelList(start, NULL)
),
T_Label(f)
)
)
)
)
)
)
);
//Pop the label as it's no longer used
LL_pop();
return Tr_Nx(st);
}
Tr_exp transDec_functionDec(Tr_level level, S_table venv, S_table tenv, A_dec d, Temp_label breakk) {
for (A_fundecList fundecs = d->u.function; fundecs; fundecs = fundecs->tail) {
S_symbol name = fundecs->head->name;
Ty_tyList formals = makeFormalTyList(tenv, fundecs->head->params);
for (A_fundecList f = d->u.function; f != fundecs; f = f->tail)
if (f->head->name == name)
EM_error(f->head->pos,
"there are two functions with the same name in the same batch "
"of mutually recursive functions");
Ty_ty result = (fundecs->head->result)? S_look(tenv, fundecs->head->result) : Ty_Void();
Temp_label label = Temp_newlabel();
U_boolList escapeList = NULL;
for (A_fieldList l = fundecs->head->params; l; l = l->tail)
// todo: handle no escape
escapeList = U_BoolList(TRUE, escapeList);
S_enter(venv, name,
E_FunEntry(Tr_newLevel(level, label, escapeList), label, formals,
result));
}
for (A_fundecList fundecs = d->u.function; fundecs; fundecs = fundecs->tail) {
S_symbol name = fundecs->head->name;
E_enventry x = S_look(venv, name);
Ty_tyList formals = x->u.fun.formals;
Ty_ty result = x->u.fun.result;
Tr_level lev = x->u.fun.level;
S_beginScope(venv);
{
A_fieldList l;
Ty_tyList t;
Tr_accessList a;
for (l = fundecs->head->params, t = formals, a = Tr_formals(lev);
l;
l = l->tail, t = t->tail, a = a->tail)
S_enter(venv, l->head->name, E_VarEntry(a->head, t->head));
// check return type
struct expty body = transExp(lev, venv, tenv, fundecs->head->body, breakk);
if (!has_same_ty(result, body.ty)) {
if (has_same_ty(result, Ty_Void()))
EM_error(fundecs->head->pos, "procedure returns value '%s'",
type_msg(body.ty));
else
EM_error(fundecs->head->pos, "return type mismatched '%s' and '%s')",
type_msg(result), type_msg(body.ty));
}
Tr_procEntryExit(lev, body.exp, a);
}
S_endScope(venv);
}
return Tr_noExp();
}
Tr_exp Tr_whileExp(Tr_exp cond, Tr_exp body){
debug("Tr_whileExp");
T_stm st;
struct Cx cx_cond = unCx(cond);
Temp_label t = Temp_newlabel();
Temp_label f = LL_peek();//Get done label from the list, which should have been prepared before this function is called.
Temp_label start = Temp_newlabel();
doPatch(cx_cond.trues, t);
doPatch(cx_cond.falses, f);
/*
T_Label start
cx_cond.stm (true->t, false->f)
T_Label(t)
body
T_Jump start
T_Label(f)
*/
st = T_Seq(T_Label(start),
T_Seq(cx_cond.stm,
T_Seq(T_Label(t),
T_Seq(unNx(body),
T_Seq(
T_Jump(
T_Name(start),
Temp_LabelList(start, NULL)
),
T_Label(f)
)
)
)
)
);
//Pop the label as it's no longer used
LL_pop();
return Tr_Nx(st);
}
static T_stm unNx(Tr_exp e){
Temp_label t,f;
T_stm st;
switch(e->kind){
case Tr_ex:
st = T_Exp(e->u.ex);
break;
case Tr_cx:
t = Temp_newlabel();
f = Temp_newlabel();
doPatch(e->u.cx.trues, t);
doPatch(e->u.cx.falses, f);
st = T_Seq(e->u.cx.stm, T_Seq(T_Label(t), T_Label(f)));
break;
case Tr_nx:
st = e->u.nx;
break;
}
return st;
}
struct expty transExp_whileExp(Tr_level level, S_table venv, S_table tenv, A_exp a, Temp_label breakk) {
struct expty test = transExp(level, venv, tenv, a->u.whilee.test, breakk);
struct expty body = transExp(level, venv, tenv, a->u.whilee.body, breakk);
if (test.ty->kind != Ty_int)
EM_error(a->u.whilee.test->pos, "expected unqualified-id");
if (body.ty->kind != Ty_void)
EM_error(a->u.whilee.test->pos, "body of while not unit");
Temp_label newbreak = Temp_newlabel();
return expTy(Tr_whileExp(test.exp, body.exp, newbreak), Ty_Void());
}
Tr_exp Tr_stringExp(string str_val){
Temp_label tl = Temp_newlabel();
F_String(tl, str_val);
return Tr_Ex(T_Name(tl));
}
Tr_exp Tr_ifExp(Tr_exp cond, Tr_exp thenb, Tr_exp elseb){
T_exp ex;
T_stm st;
Tr_exp ret;
struct Cx cx_cond = unCx(cond);
Temp_label t = Temp_newlabel();
Temp_label f = Temp_newlabel();
Temp_label join = Temp_newlabel();
doPatch(cx_cond.trues, t);
doPatch(cx_cond.falses, f);
if(elseb==NULL){
//case 1: if-then
debug("Tr_ifExp: if-then");
st = T_Seq(cx_cond.stm,
T_Seq(T_Label(t),
T_Seq(unNx(thenb),
T_Label(f)
)
)
);
ret = Tr_Nx(st);
} else {
//case 2: if-then-else
if(thenb->kind==Tr_nx && elseb->kind==Tr_nx){
debug("Tr_ifExp: if-then-else (2 nx)");
//special case: two statements
st = T_Seq(cx_cond.stm,
T_Seq(T_Label(t),
T_Seq(unNx(thenb),
T_Seq(
T_Jump(
T_Name(join),
Temp_LabelList(join, NULL)
),
T_Seq(T_Label(f),
T_Seq(unNx(elseb),
T_Label(join)
)
)
)
)
)
);
ret = Tr_Nx(st);
//TODO: special case - two cx.
} else {
debug("Tr_ifExp: if-then-else");
Temp_temp r = Temp_newtemp();
ex = T_Eseq(cx_cond.stm,
T_Eseq(T_Label(t),
T_Eseq(T_Move(T_Temp(r), unEx(thenb)),
T_Eseq(
T_Jump(
T_Name(join),
Temp_LabelList(join, NULL)
),
T_Eseq(T_Label(f),
T_Eseq(T_Move(T_Temp(r), unEx(elseb)),
T_Eseq(T_Label(join),
T_Temp(r)
)
)
)
)
)
)
);
ret = Tr_Ex(ex);
}
}
return ret;
}
void Tr_genLoopDoneLabel(){
//Put a new label into the label list
Temp_label f = Temp_newlabel();
LL_push(f);
debug("new loop done label generated");
}
Tr_level Tr_outermost(void) {
if (!outer) outer = Tr_newLevel(NULL, Temp_newlabel(), NULL);
return outer;
}
