From 52c8ca2c06da93c8d14e80a256e8996c1fa1e885 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Mon, 14 Sep 2026 21:11:03 +0200
Subject: Implement volatile operations

---
 include/elna/boot/type_check.h  | 26 +++++++++++++++++++++++---
 include/elna/gcc/elna-generic.h |  4 ++++
 2 files changed, 27 insertions(+), 3 deletions(-)

(limited to 'include')

diff --git a/include/elna/boot/type_check.h b/include/elna/boot/type_check.h
index 5faec43..582b887 100644
--- a/include/elna/boot/type_check.h
+++ b/include/elna/boot/type_check.h
@@ -181,6 +181,10 @@ namespace elna::boot
         {
             type actual;
         };
+        struct argument_not_scalar
+        {
+            type actual;
+        };
         struct constant_argument
         {
             type actual;
@@ -196,8 +200,8 @@ namespace elna::boot
         };
 
         using payload_type = std::variant<not_generic, unused_parameter,
-              argument_not_pointer, constant_argument, uninferrable_parameter,
-              shape_mismatch>;
+              argument_not_pointer, argument_not_scalar, constant_argument,
+              uninferrable_parameter, shape_mismatch>;
 
         generic_error(const source_position position, const std::string& generic_name,
                 payload_type payload);
@@ -209,6 +213,21 @@ namespace elna::boot
         payload_type payload;
     };
 
+    /**
+     * What a generic declaration accepts as a type argument.
+     *
+     * An erased generic takes a pointer, because that is what its single
+     * compiled body knows how to move.  A builtin has no body to erase, so it
+     * takes whatever it can load or store, and only a reading one tolerates a
+     * constant.
+     */
+    enum class argument_rule
+    {
+        pointer,
+        scalar,
+        mutable_scalar
+    };
+
     /**
      * Chain of responsibility for type compatibility checks.
      *
@@ -265,7 +284,8 @@ namespace elna::boot
         static bool is_equality_compatible(const type& left, const type& right);
 
         void visit_and_validate_condition(expression& condition);
-        void check_arguments(const named_expression& reference, const std::vector<type>& arguments);
+        void check_arguments(const named_expression& reference, const std::vector<type>& arguments,
+                const argument_rule rule);
         void check_parameters_used(const source_position position, const std::string& name,
                 const std::vector<type>& parameters, const type& heading);
         type infer_call(procedure_call& call, const named_expression& reference,
diff --git a/include/elna/gcc/elna-generic.h b/include/elna/gcc/elna-generic.h
index fbd68d8..dde883a 100644
--- a/include/elna/gcc/elna-generic.h
+++ b/include/elna/gcc/elna-generic.h
@@ -61,6 +61,10 @@ namespace elna::gcc
                 const std::vector<boot::type>& argument_types);
         bool build_builtin_procedures(boot::procedure_call *call);
         void build_assert_builtin(location_t call_location, const std::vector<boot::expression *>& arguments);
+        tree build_volatile_reference(location_t location, boot::expression& pointer,
+                const boot::type& accessed);
+        void build_volatile_load_builtin(location_t call_location, boot::procedure_call *call);
+        void build_volatile_store_builtin(location_t call_location, boot::procedure_call *call);
 
         void visit_statements(const std::vector<boot::statement *>& statements);
         void assert_constant();
-- 
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