[PATCH 2/8] builtin: define a symbol_op for a generic op acting on integer

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

This can be used to define some generic (polymorphic) builtin
with a signature like:
	op(T)
	op(T, T)
	op(T,T, ... T)
where T is some integer type.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 builtin.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 builtin.h |  2 ++
 2 files changed, 52 insertions(+)

diff --git a/builtin.c b/builtin.c
index ff03dbab9a06..f03bf109c818 100644
--- a/builtin.c
+++ b/builtin.c
@@ -390,6 +390,56 @@ static struct symbol_op overflow_p_op = {
 };
 
 
+///
+// Evaluate the arguments of 'generic' integer operators.
+//
+// All arguments must be the same basic integer type and
+// their number comes from the prototype and is already checked.
+static int evaluate_generic_int_op(struct expression *expr)
+{
+	struct symbol *fntype = expr->fn->ctype->ctype.base_type;
+	struct symbol_list *types = NULL;
+	struct symbol *ctype = NULL;
+	struct expression *arg;
+	struct symbol *t;
+	int n = 0;
+
+	PREPARE_PTR_LIST(fntype->arguments, t);
+	FOR_EACH_PTR(expr->args, arg) {
+		struct symbol *type;
+
+		if (++n == 1) {
+			t = arg->ctype;
+			if (!arg || !(type = arg->ctype))
+				return 0;
+			if (type->type == SYM_NODE)
+				type = type->ctype.base_type;
+			if (!type)
+				return 0;
+			if (type->ctype.base_type != &int_type || type == &bool_ctype)
+				goto err;
+		} else {
+			t = ctype;
+		}
+		add_ptr_list(&types, t);
+		NEXT_PTR_LIST(t);
+	} END_FOR_EACH_PTR(arg);
+	FINISH_PTR_LIST(t);
+	return evaluate_arguments(types, expr->args);
+
+err:
+	sparse_error(arg->pos, "non-integer type for argument %d:", n);
+	info(arg->pos, "        %s", show_typename(arg->ctype));
+	expr->ctype = &bad_ctype;
+	return 0;
+}
+
+struct symbol_op generic_int_op = {
+	.args = args_prototype,
+	.evaluate = evaluate_generic_int_op,
+};
+
+
 static int eval_atomic_common(struct expression *expr)
 {
 	struct symbol *fntype = expr->fn->ctype->ctype.base_type;
diff --git a/builtin.h b/builtin.h
index 9cb6728444fe..5fe77c926244 100644
--- a/builtin.h
+++ b/builtin.h
@@ -14,4 +14,6 @@ struct builtin_fn {
 
 void declare_builtins(int stream, const struct builtin_fn tbl[]);
 
+extern struct symbol_op generic_int_op;
+
 #endif
-- 
2.31.1