Fix ICEs with recursive type declarations

1 files changed, 25 insertions, 12 deletions

diff --git a/gcc/gcc/elna-builtins.cc b/gcc/gcc/elna-builtins.cc
index c728a00..3d10c44 100644
--- a/gcc/gcc/elna-builtins.cc
+++ b/gcc/gcc/elna-builtins.cc
@@ -170,7 +170,8 @@ namespace elna::gcc
                 static_cast<int>(procedure.parameters.size()), parameter_types.data());
     }
 
-    tree get_inner_alias(const boot::type& type, const std::shared_ptr<symbol_table>& symbols)
+    tree get_inner_alias(const boot::type& type, const std::shared_ptr<symbol_table>& symbols,
+            tree placeholder)
     {
         if (auto reference = type.get<boot::primitive_type>())
         {
@@ -181,7 +182,7 @@ namespace elna::gcc
         }
         else if (auto reference = type.get<boot::record_type>())
         {
-            tree composite_type_node = make_node(RECORD_TYPE);
+            tree composite_type_node = placeholder != NULL_TREE ? placeholder : make_node(RECORD_TYPE);
 
             if (!reference->base.empty())
             {
@@ -217,17 +218,17 @@ namespace elna::gcc
         }
         else if (auto reference = type.get<boot::pointer_type>())
         {
-            return build_pointer_type(get_inner_alias(reference->base, symbols));
+            return build_pointer_type(get_inner_alias(reference->base, symbols, placeholder));
         }
         else if (auto reference = type.get<boot::array_type>())
         {
-            tree base = get_inner_alias(reference->base, symbols);
+            tree base = get_inner_alias(reference->base, symbols, placeholder);
 
             return build_static_array_type(base, reference->size);
         }
         else if (auto reference = type.get<boot::slice_type>())
         {
-            tree base_type = get_inner_alias(reference->base, symbols);
+            tree base_type = get_inner_alias(reference->base, symbols, placeholder);
             tree slice_record = make_node(RECORD_TYPE);
             tree ptr_field = build_field(UNKNOWN_LOCATION, slice_record, "ptr",
                     build_pointer_type(base_type));
@@ -246,7 +247,7 @@ namespace elna::gcc
         }
         else if (auto reference = type.get<boot::constant_type>())
         {
-            tree unqualified = get_inner_alias(reference->unqualified, symbols);
+            tree unqualified = get_inner_alias(reference->unqualified, symbols, placeholder);
             return build_qualified_type(unqualified, TYPE_QUAL_CONST);
         }
         else if (auto reference = type.get<boot::alias_type>())
@@ -264,15 +265,28 @@ namespace elna::gcc
 
         if (looked_up == NULL_TREE)
         {
-            tree type_tree = get_inner_alias(reference->referent, symbols);
+            /*
+             * Enter a placeholder before converting the referent: a
+             * self-reference through a pointer or a slice then finds the
+             * in-progress declaration and breaks the conversion recursion.
+             */
+            tree placeholder = make_node(RECORD_TYPE);
+            looked_up = build_decl(UNKNOWN_LOCATION, TYPE_DECL,
+                    get_identifier(symbol_name.c_str()), placeholder);
+
+            TREE_PUBLIC(looked_up) = 1;
+            TYPE_NAME(placeholder) = DECL_NAME(looked_up);
+            symbols->enter(symbol_name, looked_up);
+
+            tree type_tree = get_inner_alias(reference->referent, symbols, placeholder);
             if (type_tree == error_mark_node)
             {
                 return error_mark_node;
             }
-            looked_up = build_decl(UNKNOWN_LOCATION, TYPE_DECL,
-                    get_identifier(symbol_name.c_str()), type_tree);
-
-            TREE_PUBLIC(looked_up) = 1;
+            if (type_tree != placeholder)
+            {
+                TREE_TYPE(looked_up) = type_tree;
+            }
             if (is_unique_type(type_tree))
             {
                 TYPE_NAME(type_tree) = DECL_NAME(looked_up);
@@ -282,7 +296,6 @@ namespace elna::gcc
             {
                 TYPE_NAME(type_tree) = looked_up;
             }
-            symbols->enter(symbol_name, looked_up);
         }
         return looked_up;
     }