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

---
 gcc/gcc/elna-generic.cc | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'gcc')

diff --git a/gcc/gcc/elna-generic.cc b/gcc/gcc/elna-generic.cc
index ed75fa4..3b43f5e 100644
--- a/gcc/gcc/elna-generic.cc
+++ b/gcc/gcc/elna-generic.cc
@@ -92,6 +92,46 @@ namespace elna::gcc
         }
     }
 
+    // Volatile-qualifying the pointee is what carries the guarantee into
+    // GIMPLE; the flags on the reference itself mirror what the C front end
+    // sets when it dereferences a volatile pointer.
+    tree generic_visitor::build_volatile_reference(location_t location,
+            boot::expression& pointer, const boot::type& accessed)
+    {
+        pointer.accept(this);
+
+        tree pointee = get_inner_alias(accessed, this->symbols);
+        tree qualified = build_qualified_type(pointee, TYPE_QUALS(pointee) | TYPE_QUAL_VOLATILE);
+        tree address = fold_convert_loc(location, build_pointer_type(qualified),
+                prepare_rvalue(this->current_expression));
+        tree reference = build_simple_mem_ref_loc(location, address);
+
+        TREE_THIS_VOLATILE(reference) = 1;
+        TREE_SIDE_EFFECTS(reference) = 1;
+
+        return reference;
+    }
+
+    void generic_visitor::build_volatile_load_builtin(location_t call_location,
+            boot::procedure_call *call)
+    {
+        this->current_expression = build_volatile_reference(call_location,
+                *call->arguments.at(0), call->type_decoration);
+    }
+
+    void generic_visitor::build_volatile_store_builtin(location_t call_location,
+            boot::procedure_call *call)
+    {
+        tree target = build_volatile_reference(call_location,
+                *call->arguments.at(0), call->argument_types.at(1));
+
+        call->arguments.at(1)->accept(this);
+        tree value = prepare_rvalue(this->current_expression);
+
+        this->current_expression = build2_loc(call_location, MODIFY_EXPR, void_type_node,
+                target, value);
+    }
+
     bool generic_visitor::build_builtin_procedures(boot::procedure_call *call)
     {
         const location_t call_location = get_location(&call->position());
@@ -103,6 +143,16 @@ namespace elna::gcc
                 build_assert_builtin(call_location, call->arguments);
                 return true;
             }
+            if (named_call->name == "volatile_load")
+            {
+                build_volatile_load_builtin(call_location, call);
+                return true;
+            }
+            if (named_call->name == "volatile_store")
+            {
+                build_volatile_store_builtin(call_location, call);
+                return true;
+            }
         }
         return false;
     }
-- 
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