MetadataVisualizer: CustomAttribute blob usage statistics

src/Test/PdbUtilities/Metadata/MetadataVisualizer.cs

@@ -1140,6 +1140,52 @@ private void WriteBlobs()
                 }
             }
 
+            _writer.WriteLine();
+            _writer.WriteLine("CustomAttribute sizes by constructor:");
+            foreach (var grouping in from caHandle in _reader.CustomAttributes
+                                     let ca = _reader.GetCustomAttribute(caHandle)
+                                     group ca.Constructor by ca.Value into values   // blob -> { ctor1, ctor2, ... }
+                                     group values.Key by values.First() into g      // ctor1 -> { blob1, ... }
+                                     select new { Ctor = g.Key, Size = g.Sum(ca => _reader.GetBlobReader(ca).Length) } into ctorAndSize
+                                     orderby ctorAndSize.Size descending
+                                     select ctorAndSize)
+            {
+                string typeStr = null;
+                switch (grouping.Ctor.Kind)
+                {
+                    case HandleKind.MemberReference:
+                        var memberRef = _reader.GetMemberReference((MemberReferenceHandle)grouping.Ctor);
+
+                        switch (memberRef.Parent.Kind)
+                        {
+                            case HandleKind.TypeReference:
+                                var typeRef = _reader.GetTypeReference((TypeReferenceHandle)memberRef.Parent);
+                                typeStr = typeRef.Namespace.IsNil ? _reader.GetString(typeRef.Name) : _reader.GetString(typeRef.Namespace) + "." + _reader.GetString(typeRef.Name);
+                                break;
+
+                            case HandleKind.TypeDefinition:
+                                var typeDef = _reader.GetTypeDefinition((TypeDefinitionHandle)memberRef.Parent);
+                                typeStr = typeDef.Namespace.IsNil ? _reader.GetString(typeDef.Name) : _reader.GetString(typeDef.Namespace) + "." + _reader.GetString(typeDef.Name);
+                                break;
+
+                            case HandleKind.MethodDefinition:
+                            case HandleKind.ModuleReference:
+                            case HandleKind.TypeSpecification:
+                                break;
+                        }
+
+                        break;
+
+                    case HandleKind.MethodDefinition:
+                        // TODO
+                        break;
+                }
+
+
+                // grouping.Key
+                _writer.WriteLine($"  {typeStr ?? Token(grouping.Ctor)}: {grouping.Size} bytes");
+            }
+
             _writer.WriteLine();
         }