Eliminate unnecessary ChangeType calls

azurefx · Mar 30, 2020 · cde12fa · cde12fa
1 parent 2e99bb1
commit cde12fa
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Showing 2 changed files with 11 additions and 5 deletions.
diff --git a/CLRBridge/CLRBridge.csproj b/CLRBridge/CLRBridge.csproj
@@ -2,8 +2,8 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <AssemblyVersion>0.1.0.0</AssemblyVersion>
-    <Version>0.1.0</Version>
+    <AssemblyVersion>0.1.1.0</AssemblyVersion>
+    <Version>0.1.1</Version>
   </PropertyGroup>
 
 </Project>
diff --git a/CLRBridge/Callback.cs b/CLRBridge/Callback.cs
@@ -53,9 +53,15 @@ private static Delegate CompileHandlerInvocation(Type delegateType, Func<object[
             var target = handler.Target == null ? null : Expression.Constant(handler.Target);
             var parametersObj = parameters.Select(parm => Expression.Convert(parm, typeof(object)));
             var call = Expression.Call(target, handler.Method, Expression.NewArrayInit(typeof(object), parametersObj));
-            ChangeTypeMethod method = Convert.ChangeType;
-            var changeType = Expression.Call(method.Method, call, Expression.Constant(invokeFun.ReturnType));
-            var body = invokeFun.ReturnType == typeof(void) ? (Expression)call : Expression.Convert(changeType, invokeFun.ReturnType);
+            var ret = Expression.Variable(typeof(object));
+            ChangeTypeMethod changeTypeMethod = Convert.ChangeType;
+            var typeCast = Expression.Block(new[] { ret },
+                Expression.Assign(ret, call),
+                Expression.Condition(Expression.TypeIs(ret, invokeFun.ReturnType),
+                    ret,
+                    Expression.Call(changeTypeMethod.Method, ret, Expression.Constant(invokeFun.ReturnType)))
+            );
+            var body = invokeFun.ReturnType == typeof(void) ? (Expression)call : Expression.Convert(typeCast, invokeFun.ReturnType);
             return Expression.Lambda(delegateType, body, parameters).Compile();
         }
     }