[Mlir-commits] [mlir] [MLIR][LLVM] Support Recursive DITypes (PR #80251)

[Tobias Gysi]

================
@@ -301,6 +301,70 @@ def LLVM_DIExpressionAttr : LLVM_Attr<"DIExpression", "di_expression"> {
   let assemblyFormat = "`<` ( `[` $operations^ `]` ) : (``)? `>`";
 }
 
+//===----------------------------------------------------------------------===//
+// DIRecursiveTypeAttr
+//===----------------------------------------------------------------------===//
+
+def LLVM_DIRecursiveTypeAttr : LLVM_Attr<"DIRecursiveType", "di_recursive_type",
+                                    /*traits=*/[], "DITypeAttr"> {
+  let description = [{
+    This attribute enables recursive DITypes. There are two modes for this
+    attribute.
+
+    1. If `baseType` is present:
+      - This type is considered a recursive declaration (rec-decl).
+      - The `baseType` is a self-recursive type identified by the `id` field.
+
+    2. If `baseType` is not present:
+      - This type is considered a recursive self reference (rec-self).
+      - This DIRecursiveType itself is a placeholder type that should be
+        conceptually replaced with the closet parent DIRecursiveType with the
+        same `id` field.
+
+    e.g. To represent a linked list struct:
+
+      #rec_self = di_recursive_type<self_id = 0>
+      #ptr = di_derived_type<baseType: #rec_self, ...>
+      #field = di_derived_type<name = "next", baseType: #ptr, ...>
+      #struct = di_composite_type<name = "Node", elements: #field, ...>
+      #rec = di_recursive_type<self_id = 0, baseType: #struct>
+
+      #var = di_local_variable<type = #struct_type, ...>
+
+    Note that the a rec-self without an outer rec-decl with the same id is
----------------
gysit wrote:

```suggestion
    Note that a rec-self without an outer rec-decl with the same id is
```

https://github.com/llvm/llvm-project/pull/80251