harec

commit 86e0a84d07bbdb4fbe47607d5233f51c1a3877e1
parent 689bdd02034adc68233d4e93dd233ead6d508108
Author: Drew DeVault <sir@cmpwn.com>
Date:   Thu, 31 Dec 2020 10:47:23 -0500

Implement str -> *const char cast

Diffstat:
M
src/gen.c
 | 
28
++++++++++++++++++----------
M
src/type_store.c
 | 
5
+++--

2 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/src/gen.c b/src/gen.c
@@ -556,9 +556,23 @@ gen_expr_cast(struct gen_context *ctx,
 	bool is_signed = type_is_signed(from);
 
 	struct qbe_value in = {0}, result = {0};
+	gen_temp(ctx, &result, qtype_for_type(ctx, to, false), "cast.out.%d");
+
+	// Special case: str -> *const char
+	if (to->storage == TYPE_STORAGE_POINTER
+			&& to->pointer.referent->storage == TYPE_STORAGE_CHAR
+			&& from->storage == TYPE_STORAGE_STRING) {
+		gen_temp(ctx, &in, &qbe_long, "cast.in.%d");
+		qval_address(&in);
+		gen_expression(ctx, expr->cast.value, &in);
+		qval_deref(&in);
+		gen_load(ctx, &result, &in, false);
+		gen_store(ctx, out, &result);
+		return;
+	}
+
 	gen_temp(ctx, &in, qtype_for_type(ctx, from, false), "cast.in.%d");
 	gen_expression(ctx, expr->cast.value, &in);
-	gen_temp(ctx, &result, qtype_for_type(ctx, to, false), "cast.out.%d");
 
 	enum qbe_instr op;
 	switch (to->storage) {
@@ -608,22 +622,16 @@ gen_expr_cast(struct gen_context *ctx,
 	case TYPE_STORAGE_TAGGED_UNION:
 	case TYPE_STORAGE_ENUM:
 		assert(0); // TODO
-	case TYPE_STORAGE_STRING:
-		assert(0); // TODO
-	case TYPE_STORAGE_POINTER:
-		if (to->pointer.referent->storage == TYPE_STORAGE_CHAR
-				&& from->storage == TYPE_STORAGE_STRING) {
-			assert(0); // TODO
-		}
-		// Fallthrough
 	// Can be implemented with a copy
 	case TYPE_STORAGE_ARRAY:
-	case TYPE_STORAGE_SLICE:
 	case TYPE_STORAGE_NULL:
+	case TYPE_STORAGE_POINTER:
+	case TYPE_STORAGE_SLICE:
 		pushi(ctx->current, &result, Q_COPY, &in, NULL);
 		break;
 	case TYPE_STORAGE_BOOL:
 	case TYPE_STORAGE_FUNCTION:
+	case TYPE_STORAGE_STRING:
 	case TYPE_STORAGE_STRUCT:
 	case TYPE_STORAGE_UNION:
 	case TYPE_STORAGE_VOID:
diff --git a/src/type_store.c b/src/type_store.c
@@ -154,13 +154,14 @@ type_is_castable(const struct type *to,
 		return to->storage == TYPE_STORAGE_POINTER
 			|| to->storage == TYPE_STORAGE_NULL
 			|| to->storage == TYPE_STORAGE_UINTPTR;
-	case TYPE_STORAGE_STRING:
-		return to == &builtin_type_const_ptr_char;
 	case TYPE_STORAGE_SLICE:
 	case TYPE_STORAGE_ARRAY:
 	case TYPE_STORAGE_ALIAS:
 	case TYPE_STORAGE_TAGGED_UNION:
 		assert(0); // TODO
+	case TYPE_STORAGE_STRING:
+		return to->pointer.referent->storage == TYPE_STORAGE_CHAR
+				&& to->pointer.referent->flags & TYPE_CONST;
 	case TYPE_STORAGE_RUNE:
 		return to->storage == TYPE_STORAGE_U32;
 	// Cannot be cast: