[mlir] Add a method on MLIRContext to retrieve the operations for a given dialect (#112344)

Currently we have `MLIRContext::getRegisteredOperations` which returns
all operations for the given context, with the addition of
`MLIRContext::getRegisteredOperationsByDialect` we can now retrieve the
same for a given dialect class.

Closes #111591

mlir/include/mlir/IR/MLIRContext.h

@@ -197,6 +197,11 @@ public:
   /// operations.
   ArrayRef<RegisteredOperationName> getRegisteredOperations();
 
+  /// Return a sorted array containing the information for registered operations
+  /// filtered by dialect name.
+  ArrayRef<RegisteredOperationName>
+  getRegisteredOperationsByDialect(StringRef dialectName);
+
   /// Return true if this operation name is registered in this context.
   bool isOperationRegistered(StringRef name);
 

mlir/lib/IR/MLIRContext.cpp

@@ -711,6 +711,30 @@ ArrayRef<RegisteredOperationName> MLIRContext::getRegisteredOperations() {
   return impl->sortedRegisteredOperations;
 }
 
+/// Return information for registered operations by dialect.
+ArrayRef<RegisteredOperationName>
+MLIRContext::getRegisteredOperationsByDialect(StringRef dialectName) {
+  auto lowerBound =
+      std::lower_bound(impl->sortedRegisteredOperations.begin(),
+                       impl->sortedRegisteredOperations.end(), dialectName,
+                       [](auto &lhs, auto &rhs) {
+                         return lhs.getDialect().getNamespace().compare(rhs);
+                       });
+
+  if (lowerBound == impl->sortedRegisteredOperations.end() ||
+      lowerBound->getDialect().getNamespace() != dialectName)
+    return ArrayRef<RegisteredOperationName>();
+
+  auto upperBound =
+      std::upper_bound(lowerBound, impl->sortedRegisteredOperations.end(),
+                       dialectName, [](auto &lhs, auto &rhs) {
+                         return lhs.compare(rhs.getDialect().getNamespace());
+                       });
+
+  size_t count = std::distance(lowerBound, upperBound);
+  return ArrayRef(&*lowerBound, count);
+}
+
 bool MLIRContext::isOperationRegistered(StringRef name) {
   return RegisteredOperationName::lookup(name, this).has_value();
 }