1 files changed, 27 insertions, 17 deletions

diff --git a/main.c b/main.c
index debb0ae..4f48ade 100644
--- a/main.c
+++ b/main.c
@@ -127,7 +127,7 @@ recurse:
 void parse_stmt(Lexer *l, Proc *p);
 
 /* TODO: return node from this! */
-void parse_block(Lexer *l, Proc *p, ScopeNameList *nl) {
+void parse_block(Lexer *l, Proc *p) {
 	Graph *g = &p->graph;
 	lex_next(l);
 	arena_reset(&p->scratch);
@@ -136,9 +136,6 @@ void parse_block(Lexer *l, Proc *p, ScopeNameList *nl) {
 		lex_expected_not(l, TM_EOF);
 		parse_stmt(l, p);
 	}
-	if (nl) {
-		scope_collect(&p->scope, g, nl, &p->scratch);
-	}
 	scope_pop(&p->scope, g);
 	lex_expected(l, TM_RBRACE);
 	lex_next(l);
@@ -163,7 +160,7 @@ void parse_assign(Lexer *l, Proc *p) {
 				str_fmt(&p->scratch, "possibly uninitialized %S",
 					type_desc(&e->type, &p->scratch)));
 	}
-	scope_update(b, e, &p->graph);
+	scope_update(&p->scope, b, e, &p->graph);
 }
 
 /* TODO: Implement a better system for this.
@@ -199,6 +196,7 @@ void parse_assign(Lexer *l, Proc *p) {
  *
  */
 
+#if 0
 void merge_scope(Lexer *l, Proc *p, Node *region, ScopeNameList *before, ScopeNameList *ntrue, ScopeNameList *nfalse) {
 	Graph *g = &p->graph;
 	for (int i = 0; i < before->len; i++) {
@@ -226,6 +224,7 @@ void merge_scope(Lexer *l, Proc *p, Node *region, ScopeNameList *before, ScopeNa
 		scope_update(b, phi, g);
 	}
 }
+#endif
 
 /* TODO: find out a way to encode known relations between nodes, based on the
  * conditional, within the body of an if statement --- e.g., for a statement
@@ -272,31 +271,41 @@ void parse_if(Lexer *l, Proc *p) {
 	assert(if_false->in.len > 0);
 	node_add(g, if_true, g->keepalive);
 	node_add(g, if_false, g->keepalive);
-	ScopeNameList scope_before = { 0 }, scope_true = { 0 }, scope_false = { 0 };
-	scope_collect(&p->scope, g, &scope_before, &p->scratch);
+
+	ScopeChangeList chg_if = { 0 };
+	ScopeChangeList chg_else = { 0 };
+
 	if (cond->type.lvl == T_CONST) {
 		if (cond->val.i) if_false->type.lvl = T_XCTRL;
 		else if_true->type.lvl = T_XCTRL;
 	}
+
 	ctrl(g, if_true);
 	lex_expected(l, TM_LBRACE);
 	int pos = l->pos.ofs;
-	parse_block(l, p, &scope_true);
+
+	scope_changelist_push(&p->scope, &chg_if, &p->scratch);
+	parse_block(l, p);
+	scope_changelist_pop(&p->scope, g);
+
 	if_true->src_pos = (LexSpan) { .ofs = pos, .n = l->pos.ofs - pos };
 	ctrl_if = g->ctrl;
 	node_add(g, ctrl_if, g->keepalive);
+
 	if (l->tok == TOK_ELSE) {
-		for (int i = 0; i < scope_before.len; i++) {
-			scope_update(scope_find(&p->scope, scope_before.data[i].name), scope_before.data[i].node, g);
-		}
 		ctrl(g, if_false);
 		lex_expect(l, TM_LBRACE);
 		pos = l->pos.ofs;
-		parse_block(l, p, &scope_false);
+
+		scope_changelist_push(&p->scope, &chg_else, &p->scratch);
+		parse_block(l, p);
+		scope_changelist_pop(&p->scope, g);
+
 		if_false->src_pos = (LexSpan) { .ofs = pos, .n = l->pos.ofs - pos };
 		ctrl_else = g->ctrl;
 		node_add(g, ctrl_else, g->keepalive);
 	}
+
 	Node *region;
 	if (ctrl_else) {
 		assert(ctrl_if);
@@ -320,11 +329,12 @@ void parse_if(Lexer *l, Proc *p) {
 	assert(g->ctrl->in.len > 0);
 	assert(region->in.data[0]);
 	assert(region->in.data[1]);
-	merge_scope(l, p, region, &scope_before, &scope_true, &scope_false);
-	scope_uncollect(&p->scope, g, &scope_true);
-	scope_uncollect(&p->scope, g, &scope_false);
-	scope_uncollect(&p->scope, g, &scope_before);
+
+	scope_changelist_merge(&p->scope, &chg_if, &chg_else, region, g, &p->scratch);
+	scope_changelist_discard(&chg_if, g);
+	scope_changelist_discard(&chg_else, g);
 	node_del_out(region, g->keepalive);
+
 	/* make sure we're not orphaning any phi nodes*/
 	if (g->ctrl->out.len < 1) {
 		ctrl(g, node_peephole(g->ctrl, g, l));
@@ -342,7 +352,7 @@ void parse_stmt(Lexer *l, Proc *p) {
 		parse_let(l, p);
 		break;
 	case TOK_LBRACE:
-		parse_block(l, p, NULL);
+		parse_block(l, p);
 		break;
 	case TOK_IDENT:
 		parse_assign(l, p);