From 3cdc850f2a7dbf1e170242417d67acf8d7e7b0d8 Mon Sep 17 00:00:00 2001
From: WormHeamer
Date: Sun, 3 Aug 2025 20:59:53 -0400
Subject: expand and clarify type system, fix double-free of nodes

---
 ir.c | 43 +++++++++++++++++++++++++++++--------------
 1 file changed, 29 insertions(+), 14 deletions(-)

(limited to 'ir.c')

diff --git a/ir.c b/ir.c
index c75113e..0ef19b9 100644
--- a/ir.c
+++ b/ir.c
@@ -3,9 +3,20 @@
 
 extern int no_opt;
 
+/* types */
+
+int type_eql(Type *a, Type *b) {
+	if (a->t != b->t) return 0;
+	if (a->next != b->next) return 0;
+	return a->next ? type_eql(a->next, b->next) : 1;
+}
+
+/* nodes */
+
 const char *node_type_name(NodeType t) {
 	const char *names[] = {
 		"start",
+		"projection",
 		"return",
 		"keepalive",
 		"literal",
@@ -50,18 +61,19 @@ void node_del_in(Node *n, Node *p) {
 }
 
 void node_kill(Node *n, Proc *p) {
-	for (int i = 0; i < n->in.len; i++) {
+	if (n->refs < 1) return;
+	while (n->in.len > 0) {
+		int i = --n->in.len;
 		node_del_out(n->in.data[i], n);
 		n->in.data[i]->refs--;
 		if (n->in.data[i]->out.len < 1) node_kill(n->in.data[i], p);
 	}
-	for (int i = 0; i < n->out.len; i++) {
+	while (n->out.len > 0) {
+		int i = --n->out.len;
 		node_del_in(n->out.data[i], n);
 		n->out.data[i]->refs--;
 		if (n->out.data[i]->refs < 1) node_die(n->out.data[i], p);
 	}
-	n->in.len = 0;
-	n->out.len = 0;
 	node_die(n, p);
 }
 
@@ -116,7 +128,7 @@ Node *node_dedup_lit(Proc *p, Value v) {
 	 * how many literals even usually occur in a procedure? */
 	for (int i = 0; i < p->start->out.len; i++) {
 		Node *t = p->start->out.data[i];
-		if (t->type == N_LIT && t->val.type == v.type && t->val.i == v.i) {
+		if (t->type == N_LIT && type_eql(&t->val.type, &v.type) && t->val.i == v.i) {
 			return t;
 		}
 	}
@@ -124,7 +136,7 @@ Node *node_dedup_lit(Proc *p, Value v) {
 }
 
 Node *node_new_lit_i64(Proc *p, int64_t i) {
-	Value v = (Value) { T_INT, { .i = i } };
+	Value v = (Value) { { .lvl = T_CONST, .t = T_INT }, { .i = i } };
 	Node *t = node_dedup_lit(p, v);
 	if (t) return t;
 	Node *n = node_new(p, N_LIT, p->start);
@@ -141,21 +153,24 @@ static inline int node_op_communative(NodeType t) {
 }
 
 Value node_compute(Node *n, Lexer *l) {
-	Type lit_type = T_BOT;
+	Type lit_type = { .lvl = T_BOT };
 	Node **in = n->in.data;
 	for (int i = 0; i < n->in.len; i++) {
 		Node *p = in[i];
-		if (p->type != N_LIT) break;
-		if (p->val.type != lit_type) {
-			if (lit_type == T_BOT) {
+		if (p->val.type.lvl != T_CONST) {
+			lit_type.lvl = T_BOT;
+			break;
+		}
+		if (!type_eql(&p->val.type, &lit_type)) {
+			if (lit_type.lvl == T_BOT) {
 				lit_type = p->val.type;
 			} else {
-				lit_type = T_BOT;
+				lit_type.lvl = T_BOT;
 				break;
 			}
 		}
 	}
-	if (lit_type == T_INT) {
+	if (lit_type.lvl == T_CONST && lit_type.t == T_INT) {
 		Value v = { .type = lit_type };
 		switch (n->type) {
 		case N_OP_NEG: v.i = -in[0]->val.i; break;
@@ -187,7 +202,7 @@ Node *node_peephole(Node *n, Proc *p, Lexer *l) {
 
 	if (n->type != N_LIT) {
 		Value v = node_compute(n, l);
-		if (v.type > T_CONST) {
+		if (v.type.lvl == T_CONST) {
 			node_kill(n, p);
 			Node *t = node_dedup_lit(p, v);
 			if (t) return t;
@@ -310,8 +325,8 @@ NameBinding *scope_bind(Scope *scope, Str name, Node *value, LexSpan pos, Proc *
 NameBinding *scope_update(Scope *scope, Str name, Node *to, Proc *proc) {
 	NameBinding *b = scope_find(scope, name);
 	if (!b) return NULL;
-	node_remove(proc, b->node, proc->keepalive);
 	node_add(proc, to, proc->keepalive);
+	node_remove(proc, b->node, proc->keepalive);
 	b->node = to;
 	return b;
 }
-- 
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