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Fix errors in reuse of non defined symbols

There were several errors when a symbol reused some previous
non declared symbol in a different namespace, because it was
not covering the possibility that the symbol already existed.

--- a/cc1/cc1.h

+++ b/cc1/cc1.h

@@ -311,7 +311,7 @@

 /* symbol.c */

 extern void dumpstab(char *msg);

-extern Symbol *lookup(unsigned ns);

+extern Symbol *lookup(unsigned ns, char *name);

 extern Symbol *nextsym(Symbol *sym, unsigned ns);

 extern Symbol *install(unsigned ns, Symbol *sym);

 extern Symbol *newsym(unsigned ns);

@@ -318,6 +318,7 @@

 extern void pushctx(void), popctx(void);

 extern void ikeywords(void);

 extern void delmacro(Symbol *sym);

+extern Symbol *newlabel(void);

 /* stmt.c */

 extern void compound(Symbol *lbreak, Symbol *lcont, Caselist *lswitch);

--- a/cc1/cpp.c

+++ b/cc1/cpp.c

@@ -29,7 +29,7 @@

 	Symbol *sym;

 	strcpy(yytext, s);

-	sym = lookup(NS_CPP);

+	sym = lookup(NS_CPP, yytext);

 	sym->flags |= ISDECLARED;

 	return sym;

 }

@@ -338,7 +338,7 @@

 		warn("'%s' redefined", yytext);

 		free(sym->u.s);

 	} else {

-		sym = lookup(NS_CPP);

+		sym = lookup(NS_CPP, yytext);

 		sym->flags |= ISDECLARED;

 	}

--- a/cc1/lex.c

+++ b/cc1/lex.c

@@ -378,7 +378,7 @@

 		/* nothing */;

 	input->p = p;

 	tok2str();

-	sym = lookup(lex_ns);

+	sym = lookup(lex_ns, yytext);

 	if (sym->ns == NS_CPP) {

 		if (!disexpand && expand(begin, sym))

 			return next();

--- a/cc1/stmt.c

+++ b/cc1/stmt.c

@@ -22,6 +22,7 @@

 	case TYPEIDEN:

 		if ((sym = install(NS_LABEL, yylval.sym)) == NULL)

 			error("label '%s' already defined", yytoken);

+		sym->flags |= ISDEFINED;

 		emit(OLABEL, sym);

 		next();

 		expect(':');

@@ -51,9 +52,9 @@

 	Symbol *begin, *cond, *end;

 	Node *np;

-	begin = newsym(NS_LABEL);

-	end = newsym(NS_LABEL);

-	cond = newsym(NS_LABEL);

+	begin = newlabel();

+	end = newlabel();

+	cond = newlabel();

 	expect(WHILE);

 	np = condition();

@@ -74,9 +75,9 @@

 	Symbol *begin, *cond, *end;

 	Node *econd, *einc, *einit;

-	begin = newsym(NS_LABEL);

-	end = newsym(NS_LABEL);

-	cond = newsym(NS_LABEL);

+	begin = newlabel();

+	end = newlabel();

+	cond = newlabel();

 	expect(FOR);

 	expect('(');

@@ -106,8 +107,8 @@

 	Symbol *begin, *end;

 	Node *np;

-	begin = newsym(NS_LABEL);

-	end = newsym(NS_LABEL);

+	begin = newlabel();

+	end = newlabel();

 	expect(DO);

 	emit(OBLOOP, NULL);

 	emit(OLABEL, begin);

@@ -166,12 +167,17 @@

 static void

 Goto(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)

 {

+	Symbol *sym;

+

 	setnamespace(NS_LABEL);

 	next();

 	if (yytoken != IDEN)

 		unexpected();

-	yylval.sym->flags |= ISUSED;

-	emit(OJUMP, yylval.sym);

+	sym = yylval.sym;

+	if ((sym->flags & ISDECLARED) == 0)

+		sym = install(NS_LABEL, sym);

+	sym->flags |= ISUSED;

+	emit(OJUMP, sym);

 	next();

 	expect(';');

 }

@@ -198,8 +204,8 @@

 	expect (')');

 	lcase.expr = cond;

-	lcase.lbreak = newsym(NS_LABEL);

-	lcase.ltable = newsym(NS_LABEL);

+	lcase.lbreak = newlabel();

+	lcase.ltable = newlabel();

 	emit(OSWITCH, &lcase);

 	stmt(lbreak, lcont, &lcase);

@@ -224,7 +230,7 @@

 	pcase = xmalloc(sizeof(*pcase));

 	pcase->expr = np;

 	pcase->next = lswitch->head;

-	emit(OLABEL, pcase->label = newsym(NS_LABEL));

+	emit(OLABEL, pcase->label = newlabel());

 	lswitch->head = pcase;

 	if (++lswitch->nr == NR_SWITCH)

 		error("too case labels for a switch statement");

@@ -234,7 +240,7 @@

 static void

 Default(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)

 {

-	Symbol *ldefault = newsym(NS_LABEL);

+	Symbol *ldefault = newlabel();

 	expect(DEFAULT);

 	expect(':');

@@ -250,7 +256,7 @@

 	Symbol *end, *lelse;

 	Node *np;

-	lelse = newsym(NS_LABEL);

+	lelse = newlabel();

 	expect(IF);

 	np = condition();

 	emit(OBRANCH, lelse);

@@ -257,7 +263,7 @@

 	emit(OEXPR, negate(np));

 	stmt(lbreak, lcont, lswitch);

 	if (accept(ELSE)) {

-		end = newsym(NS_LABEL);

+		end = newlabel();

 		emit(OJUMP, end);

 		emit(OLABEL, lelse);

 		stmt(lbreak, lcont, lswitch);

--- a/cc1/symbol.c

+++ b/cc1/symbol.c

@@ -110,9 +110,9 @@

 		for (sym = labels; sym; sym = next) {

 			next = sym->next;

 			f = sym->flags;

-			if ((f & (ISUSED|ISDECLARED)) == ISDECLARED)

+			if ((f & (ISUSED|ISDEFINED)) == ISDEFINED)

 				warn("'%s' defined but not used", sym->name);

-			if ((f & ISDECLARED) == 0)

+			if ((f & ISDEFINED) == 0)

 				printerr("label '%s' is not defined", sym->name);

 			free(sym->name);

 			free(sym);

@@ -171,7 +171,7 @@

 	sym->ns = ns;

 	sym->ctx = (ns == NS_CPP) ? UCHAR_MAX : curctx;

 	sym->token = IDEN;

-	sym->flags = ISDECLARED;

+	sym->flags = ISDECLARED | ISUSED;

 	sym->u.s = sym->name = NULL;

 	sym->type = NULL;

 	sym->next = sym->hash = NULL;

@@ -180,7 +180,6 @@

 		return sym;

 	if (ns == NS_LABEL) {

 		sym->next = labels;

-		sym->id = newid();

 		return labels = sym;

 	}

@@ -201,18 +200,27 @@

 }

 Symbol *

-lookup(unsigned ns)

+newlabel(void)

 {

+	Symbol *sym = newsym(NS_LABEL);

+	sym->id = newid();

+	sym->flags |= ISDEFINED;

+	return sym;

+}

+

+Symbol *

+lookup(unsigned ns, char *name)

+{

 	Symbol *sym, **h;

 	unsigned sns, v;

 	char *t, c;

-	v = hash(yytext);

+	v = hash(name);

 	h = &htab[v];

-	c = *yytext;

+	c = *name;

 	for (sym = *h; sym; sym = sym->hash) {

 		t = sym->name;

-		if (*t != c || strcmp(t, yytext))

+		if (*t != c || strcmp(t, name))

 			continue;

 		sns = sym->ns;

 		if (sns == NS_KEYWORD || sns == NS_CPP)

@@ -221,8 +229,8 @@

 			continue;

 		return sym;

 	}

-	sym = linkhash(newsym(ns), yytext, v);

-	sym->flags &= ~ISDECLARED;

+	sym = linkhash(newsym(ns), name, v);

+	sym->flags &= ~(ISDECLARED | ISUSED);

 	return sym;

 }

@@ -263,21 +271,19 @@

 Symbol *

 install(unsigned ns, Symbol *sym)

 {

-	if (sym->ctx == curctx) {

-		if (sym->flags & ISDECLARED) {

-			if (ns == sym->ns)

-				return NULL;

-		} else {

-			sym->flags |= ISDECLARED;

-			sym->ns = ns;

-			goto assign_id;

-		}

+	if (sym->ctx == curctx && ns == sym->ns) {

+		if (sym->flags & ISDECLARED)

+			return NULL;

+	} else {

+		sym = lookup(ns, sym->name);

+		if (sym->flags & ISDECLARED)

+			return sym;

 	}

-	sym = linkhash(newsym(ns), sym->name, hash(sym->name));

-assign_id:

-	if (sym->ns != NS_CPP || sym->ns != NS_LABEL)

-		sym->id = newid();

+	sym->flags |= ISDECLARED;

+	if (ns == NS_CPP)

+		return sym;

+	sym->id = newid();

 	return sym;

 }

@@ -348,8 +354,7 @@

 	for (lp = list; *lp; ++lp) {

 		for (bp = *lp; bp->str; ++bp) {

-			strcpy(yytext, bp->str);

-			sym = lookup(ns);

+			sym = lookup(ns, bp->str);

 			sym->token = bp->token;

 			sym->u.token = bp->value;

 		}

--- a/cc1/tests/test011.c

+++ b/cc1/tests/test011.c

@@ -2,6 +2,8 @@

 name: TEST011

 description: Basic test for goto

 output:

+test011.c:14: warning: 'foo' defined but not used

+test011.c:14: warning: 'start' defined but not used

 F1

 G1	F1	main

 {

--- a/cc1/tests/test012.c

+++ b/cc1/tests/test012.c

@@ -2,6 +2,7 @@

 name: TEST012

 description: Basic switch test

 output:

+test012.c:39: warning: 'foo' defined but not used

 F1

 G1	F1	main

 {

@@ -70,7 +71,7 @@

 }

 */

-

+#line 1

 int

 main()