[flang-commits] [flang] [mlir] [mlir] Support DialectRegistry extension comparison (PR #101119)

[Mehdi Amini via flang-commits]

================
@@ -173,6 +179,42 @@ bool dialect_extension_detail::hasPromisedInterface(Dialect &dialect,
 // DialectRegistry
 //===----------------------------------------------------------------------===//
 
+namespace {
+template <typename Fn>
+void applyExtensionsFn(
+    Fn &&applyExtension,
+    const llvm::MapVector<TypeID, std::unique_ptr<DialectExtensionBase>>
+        &extensions) {
+  // Note: Additional extensions may be added while applying an extension.
+  // The iterators will be invalidated if extensions are added so we'll keep
+  // a copy of the extensions for ourselves.
+
+  const auto extractExtension =
+      [](const auto &entry) -> DialectExtensionBase * {
+    return entry.second.get();
+  };
+
+  auto startIt = extensions.begin(), endIt = extensions.end();
+  size_t count = 0;
+  while (startIt != endIt) {
+    count += endIt - startIt;
+
+    // Grab the subset of extensions we'll apply in this iteration.
+    const auto subset =
+        llvm::map_to_vector(llvm::make_range(startIt, endIt), extractExtension);
+
+    // Apply!
+    for (const auto *ext : subset) {
+      applyExtension(*ext);
+    }
----------------
joker-eph wrote:

```suggestion
    for (const auto *ext : subset)
      applyExtension(*ext);
```

https://github.com/llvm/llvm-project/pull/101119