Fix GetCustomAttribute API for DllImportAttribute pseudo custom attribute

GetCustomAttribute for DllImportAttribute was throwing IndexOutOfRangeException. It made XUnit skip the rest of test methods after encoutering DllImport method in the test type.

It is regression introduced by https://github.com/dotnet/coreclr/pull/13870

Fixes https://github.com/dotnet/corefx/issues/27426

diff --git a/src/mscorlib/src/System/Reflection/CustomAttribute.cs b/src/mscorlib/src/System/Reflection/CustomAttribute.cs
index 580a34a..2614d6b 100644 (file)
--- a/src/mscorlib/src/System/Reflection/CustomAttribute.cs
+++ b/src/mscorlib/src/System/Reflection/CustomAttribute.cs
@@ -1878,38 +1878,35 @@ namespace System.Reflection
         // the only method that adds values to the Dictionary. For more details on 
         // Dictionary versus Hashtable thread safety:
         // See code:Dictionary#DictionaryVersusHashtableThreadSafety
-        private static Dictionary<RuntimeType, RuntimeType> s_pca;
-        private static int s_pcasCount;
+        private static readonly Dictionary<RuntimeType, RuntimeType> s_pca = CreatePseudoCustomAttributeDictionary();
         #endregion
 
         #region Static Constructor
-        static PseudoCustomAttribute()
-        {
-            RuntimeType[] pcas = new RuntimeType[]
-            {
-                // See //depot/DevDiv/private/Main/ndp/clr/src/MD/Compiler/CustAttr.cpp
-                typeof(FieldOffsetAttribute) as RuntimeType, // field
-                typeof(SerializableAttribute) as RuntimeType, // class, struct, enum, delegate
-                typeof(MarshalAsAttribute) as RuntimeType, // parameter, field, return-value
-                typeof(ComImportAttribute) as RuntimeType, // class, interface 
-                typeof(NonSerializedAttribute) as RuntimeType, // field, inherited
-                typeof(InAttribute) as RuntimeType, // parameter
-                typeof(OutAttribute) as RuntimeType, // parameter
-                typeof(OptionalAttribute) as RuntimeType, // parameter
-                typeof(DllImportAttribute) as RuntimeType, // method
-                typeof(PreserveSigAttribute) as RuntimeType, // method
-                typeof(TypeForwardedToAttribute) as RuntimeType, // assembly
+        static Dictionary<RuntimeType, RuntimeType> CreatePseudoCustomAttributeDictionary()
+        {
+            Type[] pcas = new Type[]
+            {
+                // See https://github.com/dotnet/coreclr/blob/master/src/md/compiler/custattr_emit.cpp
+                typeof(FieldOffsetAttribute), // field
+                typeof(SerializableAttribute), // class, struct, enum, delegate
+                typeof(MarshalAsAttribute), // parameter, field, return-value
+                typeof(ComImportAttribute), // class, interface 
+                typeof(NonSerializedAttribute), // field, inherited
+                typeof(InAttribute), // parameter
+                typeof(OutAttribute), // parameter
+                typeof(OptionalAttribute), // parameter
+                typeof(DllImportAttribute), // method
+                typeof(PreserveSigAttribute), // method
+                typeof(TypeForwardedToAttribute), // assembly
             };
 
-            s_pcasCount = pcas.Length;
-            Dictionary<RuntimeType, RuntimeType> temp_pca = new Dictionary<RuntimeType, RuntimeType>(s_pcasCount);
-
-            for (int i = 0; i < s_pcasCount; i++)
+            Dictionary<RuntimeType, RuntimeType> dict = new Dictionary<RuntimeType, RuntimeType>(pcas.Length);
+            foreach (RuntimeType runtimeType in pcas)
             {
-                VerifyPseudoCustomAttribute(pcas[i]);
-                temp_pca[pcas[i]] = pcas[i];
+                VerifyPseudoCustomAttribute(runtimeType);
+                dict[runtimeType] = runtimeType;
             }
-            s_pca = temp_pca;
+            return dict;
         }
 
         [Conditional("DEBUG")]
@@ -1935,23 +1932,22 @@ namespace System.Reflection
 
             bool all = caType == (RuntimeType)typeof(object) || caType == (RuntimeType)typeof(Attribute);
             if (!all && !s_pca.ContainsKey(caType))
-                return Array.Empty<Attribute>();
+                return null;
 
-            List<Attribute> pcas = new List<Attribute>();
+            Attribute[] pcas = new Attribute[all ? 2 : 1];
 
             if (all || caType == (RuntimeType)typeof(SerializableAttribute))
             {
                 if ((type.Attributes & TypeAttributes.Serializable) != 0)
-                    pcas.Add(new SerializableAttribute());
+                    pcas[count++] = new SerializableAttribute();
             }
             if (all || caType == (RuntimeType)typeof(ComImportAttribute))
             {
                 if ((type.Attributes & TypeAttributes.Import) != 0)
-                    pcas.Add(new ComImportAttribute());
+                    pcas[count++] = new ComImportAttribute();
             }
 
-            count = pcas.Count;
-            return pcas.ToArray();
+            return pcas;
         }
         internal static bool IsDefined(RuntimeType type, RuntimeType caType)
         {
@@ -1982,9 +1978,9 @@ namespace System.Reflection
 
             bool all = caType == (RuntimeType)typeof(object) || caType == (RuntimeType)typeof(Attribute);
             if (!all && !s_pca.ContainsKey(caType))
-                return Array.Empty<Attribute>();
+                return null;
 
-            List<Attribute> pcas = new List<Attribute>();
+            Attribute[] pcas = new Attribute[all ? 2 : 1];
             Attribute pca;
 
             if (all || caType == (RuntimeType)typeof(DllImportAttribute))
@@ -1995,11 +1991,10 @@ namespace System.Reflection
             if (all || caType == (RuntimeType)typeof(PreserveSigAttribute))
             {
                 if ((method.GetMethodImplementationFlags() & MethodImplAttributes.PreserveSig) != 0)
-                    pcas.Add(new PreserveSigAttribute());
+                    pcas[count++] = new PreserveSigAttribute();
             }
 
-            count = pcas.Count;
-            return pcas.ToArray();
+            return pcas;
         }
         internal static bool IsDefined(RuntimeMethodInfo method, RuntimeType caType)
         {
@@ -2032,7 +2027,7 @@ namespace System.Reflection
             if (!all && !s_pca.ContainsKey(caType))
                 return null;
 
-            Attribute[] pcas = new Attribute[s_pcasCount];
+            Attribute[] pcas = new Attribute[all ? 4 : 1];
             Attribute pca;
 
             if (all || caType == (RuntimeType)typeof(InAttribute))
@@ -2063,7 +2058,6 @@ namespace System.Reflection
             if (!all && !s_pca.ContainsKey(caType))
                 return false;
 
-
             if (all || caType == (RuntimeType)typeof(InAttribute))
             {
                 if (parameter.IsIn) return true;
@@ -2115,7 +2109,7 @@ namespace System.Reflection
             if (!all && !s_pca.ContainsKey(caType))
                 return null;
 
-            Attribute[] pcas = new Attribute[s_pcasCount];
+            Attribute[] pcas = new Attribute[all ? 3 : 1];
             Attribute pca;
 
             if (all || caType == (RuntimeType)typeof(MarshalAsAttribute))