From fc501ceff7fefc6ea2fdd956e2c769fcd11d9fdd Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Sun, 14 Apr 2024 23:34:15 -0700
Subject: decl: Save and re-open parameter scope for body

---
 decl.c | 49 ++++++++++++++++++++++++++++++++++---------------
 1 file changed, 34 insertions(+), 15 deletions(-)

(limited to 'decl.c')

diff --git a/decl.c b/decl.c
index 57c4a4d..96428ba 100644
--- a/decl.c
+++ b/decl.c
@@ -537,11 +537,11 @@ is used for the qualifiers of the base type). This is corrected in
 declarator().
 */
 static void
-declaratortypes(struct scope *s, struct list *result, char **name, bool allowabstract)
+declaratortypes(struct scope *s, struct list *result, char **name, struct scope **funcscope, bool allowabstract)
 {
-	struct list *ptr;
+	struct list *ptr, *prev;
 	struct type *t;
-	struct decl **p;
+	struct decl *d, **paramend;
 	struct expr *e;
 	enum typequal tq;
 	bool allowattr;
@@ -557,6 +557,7 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 	if (name)
 		*name = NULL;
 	ptr = result->next;
+	prev = ptr->prev;
 	switch (tok.kind) {
 	case TLPAREN:
 		next();
@@ -574,7 +575,7 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 				goto func;
 			}
 		}
-		declaratortypes(s, result, name, allowabstract);
+		declaratortypes(s, result, name, funcscope, allowabstract);
 		expect(TRPAREN, "after parenthesized declarator");
 		allowattr = false;
 		break;
@@ -601,10 +602,14 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 			t->u.func.isnoreturn = false;
 			t->u.func.params = NULL;
 			t->u.func.nparam = 0;
-			p = &t->u.func.params;
+			paramend = &t->u.func.params;
+			s = mkscope(s);
 			while (tok.kind != TRPAREN) {
-				*p = parameter(s);
-				p = &(*p)->next;
+				d = parameter(s);
+				if (d->name)
+					scopeputdecl(s, d);
+				*paramend = d;
+				paramend = &d->next;
 				++t->u.func.nparam;
 				if (!consume(TCOMMA))
 					break;
@@ -613,7 +618,14 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 					break;
 				}
 			}
-			if (t->u.func.nparam == 1 && !t->u.func.isvararg && t->u.func.params->type->kind == TYPEVOID && !t->u.func.params->name) {
+			if (funcscope && ptr->prev == prev) {
+				/* we may need to re-open the scope later if this is a function definition */
+				*funcscope = s;
+				s = s->parent;
+			} else {
+				s = delscope(s);
+			}
+			if (t->u.func.nparam == 1 && !t->u.func.isvararg && d->type->kind == TYPEVOID && !d->name) {
 				t->u.func.params = NULL;
 				t->u.func.nparam = 0;
 			}
@@ -655,14 +667,16 @@ declaratortypes(struct scope *s, struct list *result, char **name, bool allowabs
 }
 
 static struct qualtype
-declarator(struct scope *s, struct qualtype base, char **name, bool allowabstract)
+declarator(struct scope *s, struct qualtype base, char **name, struct scope **funcscope, bool allowabstract)
 {
 	struct type *t;
 	enum typequal tq;
 	struct expr *e;
 	struct list result = {&result, &result}, *l, *prev;
 
-	declaratortypes(s, &result, name, allowabstract);
+	if (funcscope)
+		*funcscope = NULL;
+	declaratortypes(s, &result, name, funcscope, allowabstract);
 	for (l = result.prev; l != &result; l = prev) {
 		prev = l->prev;
 		t = listelement(l, struct type, link);
@@ -715,7 +729,7 @@ parameter(struct scope *s)
 		error(&tok.loc, "no type in parameter declaration");
 	if (sc && sc != SCREGISTER)
 		error(&tok.loc, "parameter declaration has invalid storage-class specifier");
-	t = declarator(s, t, &name, true);
+	t = declarator(s, t, &name, NULL, true);
 	t.type = typeadjust(t.type, &t.qual);
 	return mkdecl(name, DECLOBJECT, t.type, t.qual, LINKNONE);
 }
@@ -855,7 +869,7 @@ structdecl(struct scope *s, struct structbuilder *b)
 			width = intconstexpr(s, false);
 			addmember(b, base, NULL, 0, width);
 		} else {
-			mt = declarator(s, base, &name, false);
+			mt = declarator(s, base, &name, NULL, false);
 			width = consume(TCOLON) ? intconstexpr(s, false) : -1;
 			addmember(b, mt, name, align, width);
 		}
@@ -874,7 +888,7 @@ typename(struct scope *s, enum typequal *tq)
 
 	t = declspecs(s, NULL, NULL, NULL);
 	if (t.type) {
-		t = declarator(s, t, NULL, true);
+		t = declarator(s, t, NULL, NULL, true);
 		if (tq)
 			*tq |= t.qual;
 	}
@@ -957,6 +971,7 @@ decl(struct scope *s, struct func *f)
 	int allowfunc = !f;
 	struct decl *d, *prior;
 	enum declkind kind;
+	struct scope *funcscope;
 	int align;
 
 	if (staticassert(s))
@@ -983,7 +998,7 @@ decl(struct scope *s, struct func *f)
 		return true;
 	}
 	for (;;) {
-		qt = declarator(s, base, &name, false);
+		qt = declarator(s, base, &name, &funcscope, false);
 		t = qt.type;
 		tq = qt.qual;
 		if (consume(T__ASM__)) {
@@ -1051,7 +1066,9 @@ decl(struct scope *s, struct func *f)
 					error(&tok.loc, "function definition not allowed");
 				if (d->defined)
 					error(&tok.loc, "function '%s' redefined", name);
-				s = mkscope(&filescope);
+				/* re-open scope from function declarator */
+				assert(funcscope);
+				s = funcscope;
 				f = mkfunc(d, name, t, s);
 				stmt(f, s);
 				/* XXX: need to keep track of function in case a later declaration specifies extern */
@@ -1061,6 +1078,8 @@ decl(struct scope *s, struct func *f)
 				delfunc(f);
 				d->defined = true;
 				return true;
+			} else if (funcscope) {
+				delscope(funcscope);
 			}
 			break;
 		}
-- 
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