harec

commit 8ffde0ac1457cb165a9fb8ab74fc967050932266
parent 760442a0e917c516282418074a9d584a1ff71df5
Author: Eyal Sawady <ecs@d2evs.net>
Date:   Tue, 16 Feb 2021 20:04:02 -0500

gen: fix cast from zero-length array to slice

We need a null data field in this case instead of a pointer to the
original array.

Diffstat:
M
src/gen.c
 | 
8
+++++++-
M
tests/08-slices.ha
 | 
14
+++++++++++---

2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/src/gen.c b/src/gen.c
@@ -1383,7 +1383,13 @@ gen_expr_cast(struct gen_context *ctx,
 		constl(&offs, 8);
 		constl(&len, from->array.length);
 		pushi(ctx->current, &ptr, Q_COPY, out, NULL);
-		pushi(ctx->current, NULL, Q_STOREL, &in, &ptr, NULL);
+		if (from->array.length == 0) {
+			struct qbe_value temp = {0};
+			constl(&temp, 0);
+			pushi(ctx->current, NULL, Q_STOREL, &temp, &ptr, NULL);
+		} else {
+			pushi(ctx->current, NULL, Q_STOREL, &in, &ptr, NULL);
+		}
 		pushi(ctx->current, &ptr, Q_ADD, &ptr, &offs, NULL);
 		pushi(ctx->current, NULL, Q_STOREL, &len, &ptr, NULL);
 		pushi(ctx->current, &ptr, Q_ADD, &ptr, &offs, NULL);
diff --git a/tests/08-slices.ha b/tests/08-slices.ha
@@ -3,12 +3,20 @@ use rt;
 fn from_array() void = {
 	let src = [1, 2, 3];
 	let x: []int = src;
-	let ptr = &x: *struct {
-		data: *[*]int,
+	let xptr = &x: *struct {
+		data: nullable *[*]int,
+		length: size,
+		capacity: size,
+	};
+	assert(xptr.data == &src);
+
+	let y: []int = [];
+	let yptr = &y: *struct {
+		data: nullable *[*]int,
 		length: size,
 		capacity: size,
 	};
-	assert(ptr.data == &src);
+	assert(yptr.data == null);
 };
 
 fn storage() void = {