[mlir] Emit errors when creating unregistered attributes/types when not allowed

[rriddle]

Summary

This was missed when verification for creating unregistered operations was added.

mlir/lib/IR/BuiltinAttributes.cpp

 // OpaqueAttr
 //===----------------------------------------------------------------------===//
 
 LogicalResult OpaqueAttr::verify(function_ref<InFlightDiagnostic()> emitError,
                                  Identifier dialect, StringRef attrData,
                                  Type type) {
   if (!Dialect::isValidNamespace(dialect.strref()))
     return emitError() << "invalid dialect namespace '" << dialect << "'";
+
+  // Check that the dialect is actually registered.
+  MLIRContext *context = dialect.getContext();
+  if (!context->allowsUnregisteredDialects() &&
+      !context->getLoadedDialect(dialect.strref())) {
+    return emitError()
+           << "#" << dialect << "<\"" << attrData << "\"> : " << type
+           << " attribute created with unregistered dialect. If this is "
+              "intended, please call allowUnregisteredDialects() on the "
+              "MLIRContext, or use -allow-unregistered-dialect with "
+              "mlir-opt";
+  }
+
   return success();
 }
 
 //===----------------------------------------------------------------------===//
 // ElementsAttr
 //===----------------------------------------------------------------------===//
 
 ShapedType ElementsAttr::getType() const {

mlir/lib/IR/BuiltinTypes.cpp

 // OpaqueType
 //===----------------------------------------------------------------------===//
 
 /// Verify the construction of an opaque type.
 LogicalResult OpaqueType::verify(function_ref<InFlightDiagnostic()> emitError,
                                  Identifier dialect, StringRef typeData) {
   if (!Dialect::isValidNamespace(dialect.strref()))
     return emitError() << "invalid dialect namespace '" << dialect << "'";
+
+  // Check that the dialect is actually registered.
+  MLIRContext *context = dialect.getContext();
+  if (!context->allowsUnregisteredDialects() &&
+      !context->getLoadedDialect(dialect.strref())) {
+    return emitError()
+           << "`!" << dialect << "<\"" << typeData << "\">"
+           << "` type created with unregistered dialect. If this is "
+              "intended, please call allowUnregisteredDialects() on the "
+              "MLIRContext, or use -allow-unregistered-dialect with "
+              "mlir-opt";
+  }
+
   return success();
 }
 
 //===----------------------------------------------------------------------===//
 // ShapedType
 //===----------------------------------------------------------------------===//
 constexpr int64_t ShapedType::kDynamicSize;
 constexpr int64_t ShapedType::kDynamicStrideOrOffset;

mlir/test/IR/attribute.mlir

-// RUN: mlir-opt %s -split-input-file -verify-diagnostics | FileCheck %s
+// RUN: mlir-opt %s -split-input-file -allow-unregistered-dialect -verify-diagnostics | FileCheck %s
 
 //===----------------------------------------------------------------------===//
 // Test integer attributes
 //===----------------------------------------------------------------------===//
 
 func @int_attrs_pass() {
   "test.int_attrs"() {
     // CHECK: any_i32_attr = 5 : ui32

mlir/test/IR/invalid-unregistered.mlir

+// RUN: mlir-opt %s -split-input-file -verify-diagnostics
+
+// expected-error @below {{op created with unregistered dialect}}
+"unregistered_dialect.op"() : () -> ()
+
+// -----
+
+// expected-error @below {{attribute created with unregistered dialect}}
+#attr = #unregistered_dialect.attribute
+
+// -----
+
+// expected-error @below {{type created with unregistered dialect}}
+!type = type !unregistered_dialect.type

mlir/unittests/IR/AttributeTest.cpp

TEST(DenseSplatTest, BF16Splat) {
   FloatType floatTy = FloatType::getBF16(&context);
   Attribute value = FloatAttr::get(floatTy, 10.0);
 
   testSplat(floatTy, value);
 }
 
 TEST(DenseSplatTest, StringSplat) {
   MLIRContext context;
+  context.allowUnregisteredDialects();
   Type stringType =
       OpaqueType::get(Identifier::get("test", &context), "string");
   StringRef value = "test-string";
   testSplat(stringType, value);
 }
 
 TEST(DenseSplatTest, StringAttrSplat) {
   MLIRContext context;
+  context.allowUnregisteredDialects();
   Type stringType =
       OpaqueType::get(Identifier::get("test", &context), "string");
   Attribute stringAttr = StringAttr::get("test-string", stringType);
   testSplat(stringType, stringAttr);
 }
 
 TEST(DenseComplexTest, ComplexFloatSplat) {
   MLIRContext context;