first commit

1 files changed, 696 insertions, 0 deletions

diff --git a/src/tools/lcc/src/stmt.c b/src/tools/lcc/src/stmt.c
new file mode 100644
index 0000000..9c3bdbe
--- /dev/null
+++ b/src/tools/lcc/src/stmt.c
@@ -0,0 +1,696 @@
+#include "c.h"
+
+
+#define SWSIZE 512
+
+#define den(i,j) ((j-buckets[i]+1.0)/(v[j]-v[buckets[i]]+1))
+
+struct code codehead = { Start };
+Code codelist = &codehead;
+float density = 0.5;
+Table stmtlabs;
+
+static int foldcond(Tree e1, Tree e2);
+static void caselabel(Swtch, long, int);
+static void cmp(int, Symbol, long, int);
+static Tree conditional(int);
+static void dostmt(int, Swtch, int);
+static int equal(Symbol, Symbol);
+static void forstmt(int, Swtch, int);
+static void ifstmt(int, int, Swtch, int);
+static Symbol localaddr(Tree);
+static void stmtlabel(void);
+static void swstmt(int, int, int);
+static void whilestmt(int, Swtch, int);
+Code code(int kind) {
+	Code cp;
+
+	if (!reachable(kind))
+		warning("unreachable code\n");
+
+	NEW(cp, FUNC);
+	cp->kind = kind;
+	cp->prev = codelist;
+	cp->next = NULL;
+	codelist->next = cp;
+	codelist = cp;
+	return cp;
+}
+int reachable(int kind) {
+
+	if (kind > Start) {
+		Code cp;
+		for (cp = codelist; cp->kind < Label; )
+			cp = cp->prev;
+		if (cp->kind == Jump || cp->kind == Switch)
+			return 0;
+	}
+	return 1;
+}
+void addlocal(Symbol p) {
+	if (!p->defined) {
+		code(Local)->u.var = p;
+		p->defined = 1;
+		p->scope = level;
+	}
+}
+void definept(Coordinate *p) {
+	Code cp = code(Defpoint);
+
+	cp->u.point.src = p ? *p : src;
+	cp->u.point.point = npoints;
+	if (ncalled > 0) {
+		int n = findcount(cp->u.point.src.file,
+			cp->u.point.src.x, cp->u.point.src.y);
+		if (n > 0)
+			refinc = (float)n/ncalled;
+	}
+	if (glevel > 2)	locus(identifiers, &cp->u.point.src);
+	if (events.points && reachable(Gen))
+		{
+			Tree e = NULL;
+			apply(events.points, &cp->u.point.src, &e);
+			if (e)
+				listnodes(e, 0, 0);
+		}
+}
+void statement(int loop, Swtch swp, int lev) {
+	float ref = refinc;
+
+	if (Aflag >= 2 && lev == 15)
+		warning("more than 15 levels of nested statements\n");
+	switch (t) {
+	case IF:       ifstmt(genlabel(2), loop, swp, lev + 1);
+ break;
+	case WHILE:    whilestmt(genlabel(3), swp, lev + 1); break;
+	case DO:       dostmt(genlabel(3), swp, lev + 1); expect(';');
+					break;
+
+	case FOR:      forstmt(genlabel(4), swp, lev + 1);
+ break;
+	case BREAK:    walk(NULL, 0, 0);
+		       definept(NULL);
+		       if (swp && swp->lab > loop)
+		       	branch(swp->lab + 1);
+		       else if (loop)
+		       	branch(loop + 2);
+		       else
+		       	error("illegal break statement\n");
+		       t = gettok(); expect(';');
+					   break;
+
+	case CONTINUE: walk(NULL, 0, 0);
+		       definept(NULL);
+		       if (loop)
+		       	branch(loop + 1);
+		       else
+		       	error("illegal continue statement\n");
+		       t = gettok(); expect(';');
+					      break;
+
+	case SWITCH:   swstmt(loop, genlabel(2), lev + 1);
+ break;
+	case CASE:     {
+		       	int lab = genlabel(1);
+		       	if (swp == NULL)
+		       		error("illegal case label\n");
+		       	definelab(lab);
+		       	while (t == CASE) {
+		       		static char stop[] = { IF, ID, 0 };
+		       		Tree p;
+		       		t = gettok();
+		       		p = constexpr(0);
+		       		if (generic(p->op) == CNST && isint(p->type)) {
+		       			if (swp) {
+		       				needconst++;
+		       				p = cast(p, swp->sym->type);
+		       				if (p->type->op == UNSIGNED)
+		       					p->u.v.i = extend(p->u.v.u, p->type);
+		       				needconst--;
+		       				caselabel(swp, p->u.v.i, lab);
+		       			}
+		       		} else
+		       			error("case label must be a constant integer expression\n");
+
+		       		test(':', stop);
+		       	}
+		       	statement(loop, swp, lev);
+		       } break;
+	case DEFAULT:  if (swp == NULL)
+		       	error("illegal default label\n");
+		       else if (swp->deflab)
+		       	error("extra default label\n");
+		       else {
+		       	swp->deflab = findlabel(swp->lab);
+		       	definelab(swp->deflab->u.l.label);
+		       }
+		       t = gettok();
+		       expect(':');
+		       statement(loop, swp, lev); break;
+	case RETURN:   {
+		       	Type rty = freturn(cfunc->type);
+		       	t = gettok();
+		       	definept(NULL);
+		       	if (t != ';')
+		       		if (rty == voidtype) {
+		       			error("extraneous return value\n");
+		       			expr(0);
+		       			retcode(NULL);
+		       		} else
+		       			retcode(expr(0));
+		       	else {
+		       		if (rty != voidtype)
+		       			warning("missing return value\n");
+		       		retcode(NULL);
+		       	}
+		       	branch(cfunc->u.f.label);
+		       } expect(';');
+					    break;
+
+	case '{':      compound(loop, swp, lev + 1); break;
+	case ';':      definept(NULL); t = gettok(); break;
+	case GOTO:     walk(NULL, 0, 0);
+		       definept(NULL);
+		       t = gettok();
+		       if (t == ID) {
+		       	Symbol p = lookup(token, stmtlabs);
+		       	if (p == NULL) {
+				p = install(token, &stmtlabs, 0, FUNC);
+				p->scope = LABELS;
+				p->u.l.label = genlabel(1);
+				p->src = src;
+			}
+		       	use(p, src);
+		       	branch(p->u.l.label);
+		       	t = gettok();
+		       } else
+		       	error("missing label in goto\n"); expect(';');
+					  break;
+
+	case ID:       if (getchr() == ':') {
+		       	stmtlabel();
+		       	statement(loop, swp, lev);
+		       	break;
+		       }
+	default:       definept(NULL);
+		       if (kind[t] != ID) {
+		       	error("unrecognized statement\n");
+		       	t = gettok();
+		       } else {
+		       	Tree e = expr0(0);
+		       	listnodes(e, 0, 0);
+		       	if (nodecount == 0 || nodecount > 200)
+		       		walk(NULL, 0, 0);
+		       	else if (glevel) walk(NULL, 0, 0);
+		       	deallocate(STMT);
+		       } expect(';');
+						break;
+
+	}
+	if (kind[t] != IF && kind[t] != ID
+	&& t != '}' && t != EOI) {
+		static char stop[] = { IF, ID, '}', 0 };
+		error("illegal statement termination\n");
+		skipto(0, stop);
+	}
+	refinc = ref;
+}
+
+static void ifstmt(int lab, int loop, Swtch swp, int lev) {
+	t = gettok();
+	expect('(');
+	definept(NULL);
+	walk(conditional(')'), 0, lab);
+	refinc /= 2.0;
+	statement(loop, swp, lev);
+	if (t == ELSE) {
+		branch(lab + 1);
+		t = gettok();
+		definelab(lab);
+		statement(loop, swp, lev);
+		if (findlabel(lab + 1)->ref)
+			definelab(lab + 1);
+	} else
+		definelab(lab);
+}
+static Tree conditional(int tok) {
+	Tree p = expr(tok);
+
+	if (Aflag > 1 && isfunc(p->type))
+		warning("%s used in a conditional expression\n",
+			funcname(p));
+	return cond(p);
+}
+static void stmtlabel(void) {
+	Symbol p = lookup(token, stmtlabs);
+
+	if (p == NULL) {
+		p = install(token, &stmtlabs, 0, FUNC);
+		p->scope = LABELS;
+		p->u.l.label = genlabel(1);
+		p->src = src;
+	}
+	if (p->defined)
+		error("redefinition of label `%s' previously defined at %w\n", p->name, &p->src);
+
+	p->defined = 1;
+	definelab(p->u.l.label);
+	t = gettok();
+	expect(':');
+}
+static void forstmt(int lab, Swtch swp, int lev) {
+	int once = 0;
+	Tree e1 = NULL, e2 = NULL, e3 = NULL;
+	Coordinate pt2, pt3;
+	
+	t = gettok();
+	expect('(');
+	definept(NULL);
+	if (kind[t] == ID)
+		e1 = texpr(expr0, ';', FUNC);
+	else
+		expect(';');
+	walk(e1, 0, 0);
+	pt2 = src;
+	refinc *= 10.0;
+	if (kind[t] == ID)
+		e2 = texpr(conditional, ';', FUNC);
+	else
+		expect(';');
+	pt3 = src;
+	if (kind[t] == ID)
+		e3 = texpr(expr0, ')', FUNC);
+	else {
+		static char stop[] = { IF, ID, '}', 0 };
+		test(')', stop);
+	}
+	if (e2) {
+		once = foldcond(e1, e2);
+		if (!once)
+			branch(lab + 3);
+	}
+	definelab(lab);
+	statement(lab, swp, lev);
+	definelab(lab + 1);
+	definept(&pt3);
+	if (e3)
+		walk(e3, 0, 0);
+	if (e2) {
+		if (!once)
+			definelab(lab + 3);
+		definept(&pt2);
+		walk(e2, lab, 0);
+	} else {
+		definept(&pt2);
+		branch(lab);
+	}
+	if (findlabel(lab + 2)->ref)
+		definelab(lab + 2);
+}
+static void swstmt(int loop, int lab, int lev) {
+	Tree e;
+	struct swtch sw;
+	Code head, tail;
+
+	t = gettok();
+	expect('(');
+	definept(NULL);
+	e = expr(')');
+	if (!isint(e->type)) {
+		error("illegal type `%t' in switch expression\n",
+			e->type);
+		e = retype(e, inttype);
+	}
+	e = cast(e, promote(e->type));
+	if (generic(e->op) == INDIR && isaddrop(e->kids[0]->op)
+	&& e->kids[0]->u.sym->type == e->type
+	&& !isvolatile(e->kids[0]->u.sym->type)) {
+		sw.sym = e->kids[0]->u.sym;
+		walk(NULL, 0, 0);
+	} else {
+		sw.sym = genident(REGISTER, e->type, level);
+		addlocal(sw.sym);
+		walk(asgn(sw.sym, e), 0, 0);
+	}
+	head = code(Switch);
+	sw.lab = lab;
+	sw.deflab = NULL;
+	sw.ncases = 0;
+	sw.size = SWSIZE;
+	sw.values = newarray(SWSIZE, sizeof *sw.values, FUNC);
+	sw.labels = newarray(SWSIZE, sizeof *sw.labels, FUNC);
+	refinc /= 10.0;
+	statement(loop, &sw, lev);
+	if (sw.deflab == NULL) {
+		sw.deflab = findlabel(lab);
+		definelab(lab);
+		if (sw.ncases == 0)
+			warning("switch statement with no cases\n");
+	}
+	if (findlabel(lab + 1)->ref)
+		definelab(lab + 1);
+	tail = codelist;
+	codelist = head->prev;
+	codelist->next = head->prev = NULL;
+	if (sw.ncases > 0)
+		swgen(&sw);
+	branch(lab);
+	head->next->prev = codelist;
+	codelist->next = head->next;
+	codelist = tail;
+}
+static void caselabel(Swtch swp, long val, int lab) {
+	int k;
+
+	if (swp->ncases >= swp->size)
+		{
+		long   *vals = swp->values;
+		Symbol *labs = swp->labels;
+		swp->size *= 2;
+		swp->values = newarray(swp->size, sizeof *swp->values, FUNC);
+		swp->labels = newarray(swp->size, sizeof *swp->labels, FUNC);
+		for (k = 0; k < swp->ncases; k++) {
+			swp->values[k] = vals[k];
+			swp->labels[k] = labs[k];
+		}
+		}
+	k = swp->ncases;
+	for ( ; k > 0 && swp->values[k-1] >= val; k--) {
+		swp->values[k] = swp->values[k-1];
+		swp->labels[k] = swp->labels[k-1];
+	}
+	if (k < swp->ncases && swp->values[k] == val)
+		error("duplicate case label `%d'\n", val);
+	swp->values[k] = val;
+	swp->labels[k] = findlabel(lab);
+	++swp->ncases;
+	if (Aflag >= 2 && swp->ncases == 258)
+		warning("more than 257 cases in a switch\n");
+}
+void swgen(Swtch swp) {
+	int *buckets, k, n;
+	long *v = swp->values;
+
+	buckets = newarray(swp->ncases + 1,
+		sizeof *buckets, FUNC);
+	for (n = k = 0; k < swp->ncases; k++, n++) {
+		buckets[n] = k;
+		while (n > 0 && den(n-1, k) >= density)
+			n--;
+	}
+	buckets[n] = swp->ncases;
+	swcode(swp, buckets, 0, n - 1);
+}
+void swcode(Swtch swp, int b[], int lb, int ub) {
+	int hilab, lolab, l, u, k = (lb + ub)/2;
+	long *v = swp->values;
+
+	if (k > lb && k < ub) {
+		lolab = genlabel(1);
+		hilab = genlabel(1);
+	} else if (k > lb) {
+		lolab = genlabel(1);
+		hilab = swp->deflab->u.l.label;
+	} else if (k < ub) {
+		lolab = swp->deflab->u.l.label;
+		hilab = genlabel(1);
+	} else
+		lolab = hilab = swp->deflab->u.l.label;
+	l = b[k];
+	u = b[k+1] - 1;
+	if (u - l + 1 <= 3)
+		{
+			int i;
+			for (i = l; i <= u; i++)
+				cmp(EQ, swp->sym, v[i], swp->labels[i]->u.l.label);
+			if (k > lb && k < ub)
+				cmp(GT, swp->sym, v[u], hilab);
+			else if (k > lb)
+				cmp(GT, swp->sym, v[u], hilab);
+			else if (k < ub)
+				cmp(LT, swp->sym, v[l], lolab);
+			else
+				assert(lolab == hilab),
+				branch(lolab);
+			walk(NULL, 0, 0);
+		}
+	else {
+		Tree e;
+		Type ty = signedint(swp->sym->type);
+		Symbol table = genident(STATIC,
+			array(voidptype, u - l + 1, 0), GLOBAL);
+		(*IR->defsymbol)(table);
+		if (!isunsigned(swp->sym->type) || v[l] != 0)
+			cmp(LT, swp->sym, v[l], lolab);
+		cmp(GT, swp->sym, v[u], hilab);
+		e = (*optree['-'])(SUB, cast(idtree(swp->sym), ty), cnsttree(ty, v[l]));
+		if (e->type->size < unsignedptr->size)
+			e = cast(e, unsignedlong);
+		walk(tree(JUMP, voidtype,
+			rvalue((*optree['+'])(ADD, pointer(idtree(table)), e)), NULL),
+			0, 0);
+		code(Switch);
+		codelist->u.swtch.table = table;
+		codelist->u.swtch.sym = swp->sym;
+		codelist->u.swtch.deflab = swp->deflab;
+		codelist->u.swtch.size = u - l + 1;
+		codelist->u.swtch.values = &v[l];
+		codelist->u.swtch.labels = &swp->labels[l];
+		if (v[u] - v[l] + 1 >= 10000)
+			warning("switch generates a huge table\n");
+	}
+	if (k > lb) {
+		assert(lolab != swp->deflab->u.l.label);
+		definelab(lolab);
+		swcode(swp, b, lb, k - 1);
+	}
+	if (k < ub) {
+		assert(hilab != swp->deflab->u.l.label);
+		definelab(hilab);
+		swcode(swp, b, k + 1, ub);
+	}
+}
+static void cmp(int op, Symbol p, long n, int lab) {
+	Type ty = signedint(p->type);
+
+	listnodes(eqtree(op,
+			cast(idtree(p), ty),
+			cnsttree(ty, n)),
+		lab, 0);
+}
+void retcode(Tree p) {
+	Type ty;
+
+	if (p == NULL) {
+		if (events.returns)
+			apply(events.returns, cfunc, NULL);
+		return;
+	}
+	p = pointer(p);
+	ty = assign(freturn(cfunc->type), p);
+	if (ty == NULL) {
+		error("illegal return type; found `%t' expected `%t'\n",
+			p->type, freturn(cfunc->type));
+		return;
+	}
+	p = cast(p, ty);
+	if (retv)
+		{
+			if (iscallb(p))
+				p = tree(RIGHT, p->type,
+					tree(CALL+B, p->type,
+						p->kids[0]->kids[0], idtree(retv)),
+					rvalue(idtree(retv)));
+			else
+				p = asgntree(ASGN, rvalue(idtree(retv)), p);
+			walk(p, 0, 0);
+			if (events.returns)
+				apply(events.returns, cfunc, rvalue(idtree(retv)));
+			return;
+		}
+	if (events.returns)
+		{
+			Symbol t1 = genident(AUTO, p->type, level);
+			addlocal(t1);
+			walk(asgn(t1, p), 0, 0);
+			apply(events.returns, cfunc, idtree(t1));
+			p = idtree(t1);
+		}
+	if (!isfloat(p->type))
+		p = cast(p, promote(p->type));
+	if (isptr(p->type))
+		{
+			Symbol q = localaddr(p);
+			if (q && (q->computed || q->generated))
+				warning("pointer to a %s is an illegal return value\n",
+					q->scope == PARAM ? "parameter" : "local");
+			else if (q)
+				warning("pointer to %s `%s' is an illegal return value\n",
+					q->scope == PARAM ? "parameter" : "local", q->name);
+		}
+	walk(tree(mkop(RET,p->type), p->type, p, NULL), 0, 0);
+}
+void definelab(int lab) {
+	Code cp;
+	Symbol p = findlabel(lab);
+
+	assert(lab);
+	walk(NULL, 0, 0);
+	code(Label)->u.forest = newnode(LABEL+V, NULL, NULL, p);
+	for (cp = codelist->prev; cp->kind <= Label; )
+		cp = cp->prev;
+	while (   cp->kind == Jump
+	       && cp->u.forest->kids[0]
+	       && specific(cp->u.forest->kids[0]->op) == ADDRG+P
+	       && cp->u.forest->kids[0]->syms[0] == p) {
+		assert(cp->u.forest->kids[0]->syms[0]->u.l.label == lab);
+		p->ref--;
+		assert(cp->next);
+		assert(cp->prev);
+		cp->prev->next = cp->next;
+		cp->next->prev = cp->prev;
+		cp = cp->prev;
+		while (cp->kind <= Label)
+			cp = cp->prev;
+	}
+}
+Node jump(int lab) {
+	Symbol p = findlabel(lab);
+
+	p->ref++;
+	return newnode(JUMP+V, newnode(ADDRG+ttob(voidptype), NULL, NULL, p),
+		NULL, NULL);
+}
+void branch(int lab) {
+	Code cp;
+	Symbol p = findlabel(lab);
+
+	assert(lab);
+	walk(NULL, 0, 0);
+	code(Label)->u.forest = jump(lab);
+	for (cp = codelist->prev; cp->kind < Label; )
+		cp = cp->prev;
+	while (   cp->kind == Label
+	       && cp->u.forest->op == LABEL+V
+	       && !equal(cp->u.forest->syms[0], p)) {
+		equatelab(cp->u.forest->syms[0], p);
+		assert(cp->next);
+		assert(cp->prev);
+		cp->prev->next = cp->next;
+		cp->next->prev = cp->prev;
+		cp = cp->prev;
+		while (cp->kind < Label)
+			cp = cp->prev;
+	}
+	if (cp->kind == Jump || cp->kind == Switch) {
+		p->ref--;
+		codelist->prev->next = NULL;
+		codelist = codelist->prev;
+	} else {
+		codelist->kind = Jump;
+		if (cp->kind == Label
+		&&  cp->u.forest->op == LABEL+V
+		&&  equal(cp->u.forest->syms[0], p))
+			warning("source code specifies an infinite loop");
+	}
+}
+void equatelab(Symbol old, Symbol new) {
+	assert(old->u.l.equatedto == NULL);
+	old->u.l.equatedto = new;
+	new->ref++;
+}
+static int equal(Symbol lprime, Symbol dst) {
+	assert(dst && lprime);
+	for ( ; dst; dst = dst->u.l.equatedto)
+		if (lprime == dst)
+			return 1;
+	return 0;
+}
+/* dostmt - do statement while ( expression ) */
+static void dostmt(int lab, Swtch swp, int lev) {
+	refinc *= 10.0;
+	t = gettok();
+	definelab(lab);
+	statement(lab, swp, lev);
+	definelab(lab + 1);
+	expect(WHILE);
+	expect('(');
+	definept(NULL);
+	walk(conditional(')'), lab, 0);
+	if (findlabel(lab + 2)->ref)
+		definelab(lab + 2);
+}
+
+/* foldcond - check if initial test in for(e1;e2;e3) S is necessary */
+static int foldcond(Tree e1, Tree e2) {
+	int op = generic(e2->op);
+	Symbol v;
+
+	if (e1 == 0 || e2 == 0)
+		return 0;
+	if (generic(e1->op) == ASGN && isaddrop(e1->kids[0]->op)
+	&& generic(e1->kids[1]->op) == CNST) {
+		v = e1->kids[0]->u.sym;
+		e1 = e1->kids[1];
+	} else
+		return 0;
+	if ((op==LE || op==LT || op==EQ || op==NE || op==GT || op==GE)
+	&& generic(e2->kids[0]->op) == INDIR
+	&& e2->kids[0]->kids[0]->u.sym == v
+	&& e2->kids[1]->op == e1->op) {
+		e1 = simplify(op, e2->type, e1, e2->kids[1]);
+		if (e1->op == CNST+I)
+			return e1->u.v.i;
+	}
+	return 0;
+}
+
+/* localaddr - returns q if p yields the address of local/parameter q; otherwise returns 0 */
+static Symbol localaddr(Tree p) {
+	if (p == NULL)
+		return NULL;
+	switch (generic(p->op)) {
+	case INDIR: case CALL: case ARG:
+		return NULL;
+	case ADDRL: case ADDRF:
+		return p->u.sym;
+	case RIGHT: case ASGN:
+		if (p->kids[1])
+			return localaddr(p->kids[1]);
+		return localaddr(p->kids[0]);
+	case COND: {
+		Symbol q;
+		assert(p->kids[1] && p->kids[1]->op == RIGHT);
+		if ((q = localaddr(p->kids[1]->kids[0])) != NULL)
+			return q;
+		return localaddr(p->kids[1]->kids[1]);
+		}
+	default: {
+		Symbol q;
+		if (p->kids[0] && (q = localaddr(p->kids[0])) != NULL)
+			return q;
+		return localaddr(p->kids[1]);
+		}
+	}
+}
+
+/* whilestmt - while ( expression ) statement */
+static void whilestmt(int lab, Swtch swp, int lev) {
+	Coordinate pt;
+	Tree e;
+
+	refinc *= 10.0;
+	t = gettok();
+	expect('(');
+	walk(NULL, 0, 0);
+	pt = src;
+	e = texpr(conditional, ')', FUNC);
+	branch(lab + 1);
+	definelab(lab);
+	statement(lab, swp, lev);
+	definelab(lab + 1);
+	definept(&pt);
+	walk(e, lab, 0);
+	if (findlabel(lab + 2)->ref)
+		definelab(lab + 2);
+}