[llvm] [mlir] [mlir] Add symbol user attribute interface. (PR #153206)

[Jacques Pienaar via llvm-commits]

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@@ -511,7 +511,14 @@ LogicalResult detail::verifySymbolTable(Operation *op) {
   SymbolTableCollection symbolTable;
   auto verifySymbolUserFn = [&](Operation *op) -> std::optional<WalkResult> {
     if (SymbolUserOpInterface user = dyn_cast<SymbolUserOpInterface>(op))
-      return WalkResult(user.verifySymbolUses(symbolTable));
+      if (failed(user.verifySymbolUses(symbolTable)))
+        return WalkResult::interrupt();
+    for (auto &attr : op->getAttrs()) {
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jpienaar wrote:

Properties are bits that only has meaning for an operation today. There is no generic interpretation. If properties had interfaces, then one could query an interface here in the same way. I see this not as inhibiting nor prerequisite here. And indeed today the only way would be via SymbolUserOpInterface, one could additionally factor out common function C++ side that could be used in both.

In practice, this is very useful for composition between dialects where one isn't the sole owner. I have a few pipelines where this would be used where the alternatives require coupling, rearchitecting, some interface injection (which doesn't quite work), doing a bit of silly additions of attributes/adding registries or just having a worse error & debugging experience. So just covering discardable attributes suffices in improving error localization sufficiently for such cases. 

https://github.com/llvm/llvm-project/pull/153206