harec

commit f7e8c9f1b41ff5c9430147fe483b1b890552a140
parent 8bc045be450b1a4f5fd0b8da11315a26fee8fd4b
Author: Drew DeVault <sir@cmpwn.com>
Date:   Tue,  2 Feb 2021 17:23:27 -0500

gen: implement match transitivity

Diffstat:
M
src/gen.c
 | 
38
+++++++++++++++++++++++++++++---------
M
tests/18-match.ha
 | 
60
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 89 insertions(+), 9 deletions(-)
diff --git a/src/gen.c b/src/gen.c
@@ -1515,17 +1515,37 @@ gen_match_tagged(struct gen_context *ctx,
 		fbranch.kind = QV_LABEL;
 		fbranch.name = strdup(genl(&flabel, &ctx->id, "next.case.%d"));
 
-		const struct type *intermediate =
-			tagged_select_subtype(mtype, _case->type);
-		if (intermediate->id != _case->type->id) {
-			assert(0); // TODO
-		}
+		struct qbe_value temp_tag = {0}, subval = {0}, offs = {0};
+		gen_temp(ctx, &subval, &qbe_long, "subtag.ptr.%d");
+		gen_temp(ctx, &temp_tag, &qbe_word, "subtag.tag.%d");
+		pushi(ctx->current, &subval, Q_COPY, &mval, NULL);
+		struct qbe_value *curtag = &tag;
+		const struct type *subtype = mtype;
+		const struct type *test = _case->type;
+		do {
+			struct qbe_statement slabel = {0};
+			struct qbe_value sbranch = {0};
+			sbranch.kind = QV_LABEL;
+			sbranch.name = strdup(genl(&slabel, &ctx->id, "match.subtype.%d"));
+
+			test = tagged_select_subtype(subtype, _case->type);
+			constw(&match, test->id);
+			pushi(ctx->current, &temp, Q_CEQW, &match, curtag, NULL);
+			pushi(ctx->current, NULL, Q_JNZ, &temp, &sbranch, &fbranch, NULL);
+			push(&ctx->current->body, &slabel);
+
+			if (test->id != _case->type->id) {
+				constl(&offs, subtype->align);
+				pushi(ctx->current, &subval, Q_ADD, &subval, &offs, NULL);
+				pushi(ctx->current, &temp_tag, Q_LOADUW, &subval, NULL);
+				curtag = &temp_tag;
+			}
 
-		constw(&match, _case->type->id);
-		pushi(ctx->current, &temp, Q_CEQW, &match, &tag, NULL);
-		pushi(ctx->current, NULL, Q_JNZ, &temp, &tbranch, &fbranch, NULL);
-		push(&ctx->current->body, &tlabel);
+			subtype = test;
+		} while (test->id != _case->type->id);
+		pushi(ctx->current, NULL, Q_JMP, &tbranch, NULL);
 
+		push(&ctx->current->body, &tlabel);
 		if (_case->object) {
 			struct qbe_value val = {0}, temp = {0};
 			gen_temp(ctx, &val,
diff --git a/tests/18-match.ha b/tests/18-match.ha
@@ -92,6 +92,65 @@ fn implicit_cast() void = {
 	assert(a is foobar);
 };
 
+type foo = void;
+type bar = void;
+type foobar = (foo | bar);
+type baz = int;
+type foobarbaz = (foobar | baz);
+
+fn transitivity() void = {
+	let x: (foobar | int) = 10;
+	match (x) {
+		i: int => assert(i == 10),
+		foo => abort(),
+		bar => abort(),
+	};
+
+	x = foo;
+	let visit = false;
+	match (x) {
+		int => abort(),
+		foo => {
+			visit = true;
+		},
+		bar => abort(),
+	};
+	assert(visit);
+
+	x = bar;
+	visit = false;
+	match (x) {
+		int    => abort(),
+		foo    => abort(),
+		foobar => {
+			visit = true;
+		},
+	};
+	assert(visit);
+
+	let y: foobarbaz = 10;
+	visit = false;
+	match (y) {
+		baz => {
+			visit = true;
+		},
+		foo => abort(),
+		bar => abort(),
+	};
+	assert(visit);
+
+	y = foo;
+	visit = false;
+	match (y) {
+		baz => abort(),
+		foo => {
+			visit = true;
+		},
+		bar => abort(),
+	};
+	assert(visit);
+};
+
 export fn main() void = {
 	tagged();
 	termination();
@@ -100,5 +159,6 @@ export fn main() void = {
 	alias();
 	tagged_result();
 	implicit_cast();
+	transitivity();
 	// TODO: Test exhaustiveness and dupe detection
 };