[Mlir-commits] [mlir] [mlir] Add property combinators, initial ODS support (PR #94732)

[Christian Ulmann]

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@@ -68,18 +69,67 @@ class Property<string storageTypeParam = "", string desc = ""> {
   // - `$_storage` is the variable to hash.
   //
   // The expression should define a llvm::hash_code.
-  code hashProperty = [{
-    llvm::hash_value($_storage);
+  // If unspecified, defaults to `llvm::hash_value($_storage)`.
+  // The default is not specified in tablegen because many combinators, like
+  // ArrayProperty, can fall back to more efficient implementations of
+  // `hashProperty` when their underlying elements have trivial hashing.
+  code hashProperty = "";
+
+  // The body of the parser for a value of this property.
+  // Format:
+  // - `$_parser` is the OpAsmParser.
+  // - `$_storage` is the location into which the value is to be placed if it is
+  //  present.
+  // - `$_cxtx` is a `MLIRContext *`
+  //
+  // This defines the body of a function (typically a lambda) that returns a
+  // ParseResult. There is an implicit `return success()` at the end of the parser
+  // code.
+  //
+  // When this code executes, `$_storage` will be initialized to the property's
+  // default value (if any, accounting for the storage type override).
+  code parser = [{
+    auto value = ::mlir::FieldParser<}] # storageType # [{>::parse($_parser);
+    if (::mlir::failed(value))
+      return ::mlir::failure();
+    $_storage = std::move(*value);
   }];
 
+  // The body of the parser for a value of this property as the anchor of an optional
+  // group. This should parse the property if possible and do nothing if a value of
+  // the relevant type is not next in the parse stream.
+  // You are not required to define this parser if it cannot be meaningfully
+  // implemented.
+  // This has the same context and substitutions as `parser` except that it is
+  // required to return an OptionalParseResult.
+  //
+  // Note that the printer for a property should always print a non-empty value.
+  //
----------------
Dinistro wrote:

Should this be moved downwards to the printer's comment?

https://github.com/llvm/llvm-project/pull/94732