harec

commit 17628e5e79de400e908e214454454aaef5834e3b
parent 9d1d4f3a8d66ce1d0df74e528b770586b712074f
Author: Drew DeVault <sir@cmpwn.com>
Date:   Mon,  2 Aug 2021 11:39:30 +0200

gen: implement -at variant of gen_expr_list

It would be nice to merge these. Only ever using the _at form for
expression lists risks generating extra storage when not required, for
instance:

let x: []int = ...
let y = x[{
	z;
}];

Signed-off-by: Drew DeVault <sir@cmpwn.com>

Diffstat:
M
src/gen.c
 | 
24
+++++++++++++++++++++---

1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/src/gen.c b/src/gen.c
@@ -207,6 +207,7 @@ gen_expr_const(struct gen_context *ctx, const struct expression *expr)
 	abort(); // Invariant
 }
 
+// TODO: Decide how/if gen_expr_list and gen_expr_list_at should be merged
 static struct gen_value
 gen_expr_list(struct gen_context *ctx, const struct expression *expr)
 {
@@ -221,6 +222,21 @@ gen_expr_list(struct gen_context *ctx, const struct expression *expr)
 	abort(); // Unreachable
 }
 
+static void
+gen_expr_list_at(struct gen_context *ctx,
+	const struct expression *expr,
+	struct gen_value out)
+{
+	// TODO: Set up defer scope
+	for (const struct expressions *exprs = &expr->list.exprs;
+			exprs; exprs = exprs->next) {
+		if (!exprs->next) {
+			gen_expr_at(ctx, exprs->expr, out);
+		}
+		gen_expr(ctx, exprs->expr);
+	}
+}
+
 static struct gen_value
 gen_expr_return(struct gen_context *ctx, const struct expression *expr)
 {
@@ -313,8 +329,7 @@ gen_expr(struct gen_context *ctx, const struct expression *expr)
 	case EXPR_UNARITHM:
 		assert(0); // TODO
 	case EXPR_STRUCT:
-		// Prefers _at style
-		break;
+		break; // Prefers -at style
 	}
 
 	struct gen_value out = mktemp(ctx, expr->result, "object.%d");
@@ -334,11 +349,14 @@ gen_expr_at(struct gen_context *ctx,
 	assert(out.kind != GV_CONST);
 
 	switch (expr->type) {
+	case EXPR_LIST:
+		gen_expr_list_at(ctx, expr, out);
+		return;
 	case EXPR_STRUCT:
 		gen_expr_struct_at(ctx, expr, out);
 		return;
 	default:
-		break; // Does not have an _at implementation
+		break; // Prefers non-at style
 	}
 
 	gen_store(ctx, out, gen_expr(ctx, expr));