[Mlir-commits] [mlir] [mlir][EmitC] Create a pass to add a reflection map to a class (PR #205464)

[Andrzej Warzyński]

================
@@ -60,4 +60,49 @@ def WrapFuncInClassPass : Pass<"wrap-emitc-func-in-class", "ModuleOp"> {
   ];
 }
 
+def MLGOAddReflectionMapPass : Pass<"mlgo-add-reflection-map", "ModuleOp"> {
+  let summary = "Add a reflection map and a helper method to EmitC classes for runtime field lookup.";
+  let description = [{
+    This pass adds a `reflectionMap` field and an accompanying `getBufferForName` method to 
+    EmitC classes, enabling runtime lookup of class fields by name. 
+    This requires that the class has fields with attributes.
+    Each `emitc.field` is expected to have an attribute (configured by the
+    `included-field-attrs` option) that is an array containing a single string
+    attribute. If a field possesses both an attribute specified by
+    `included-field-attrs` and an attribute specified in `excluded-field-attrs`,
+    the `included-field-attrs` attribute takes precedence and the field will be
+    included in the reflection map.
----------------
banach-space wrote:

This is a bit confusing.

1. Why is `included-field-attrs` given precedence? That's very arbitrary. Why doesn't the pass prioritise in the order of specification? Or, select the right-most one (i.e. the last one that was added).
2. Do we really need both attributes? I would expect `included-field-attrs` to be sufficient to model everything that is required. 

My suggestion - remove `excluded-field-attrs` and keep `included-field-attrs`. Based on the tests taht I have seen, one set should be enough. Everything else that is not listed in `included-field-attrs` should be ignored. Will that work?

https://github.com/llvm/llvm-project/pull/205464