Fix illegal delegate usage

BadSingleton · BadSingleton · commit 5d9f76f4815f · 2020-12-17T13:17:17.000-05:00
Cache the delegates to native code we've created so that when we need to
call that delegate, we don't ask for a delegate from a native pointer
(that is a delegate to managed code.)
diff --git a/src/runtime/interop.cs b/src/runtime/interop.cs
@@ -491,6 +491,9 @@ internal static Type GetPrototype(string name)
             return pmap[name] as Type;
         }
 
+
+        internal static Dictionary<IntPtr, Delegate> allocatedThunks = new Dictionary<IntPtr, Delegate>();
+
         internal static ThunkInfo GetThunk(MethodInfo method, string funcType = null)
         {
             Type dt;
@@ -505,6 +508,7 @@ internal static ThunkInfo GetThunk(MethodInfo method, string funcType = null)
             }
             Delegate d = Delegate.CreateDelegate(dt, method);
             var info = new ThunkInfo(d);
+            allocatedThunks[info.Address] = d;
             return info;
         }
 
diff --git a/src/runtime/managedtype.cs b/src/runtime/managedtype.cs
@@ -178,7 +178,7 @@ internal static int PyVisit(IntPtr ob, IntPtr visit, IntPtr arg)
             {
                 return 0;
             }
-            var visitFunc = (Interop.ObjObjFunc)Marshal.GetDelegateForFunctionPointer(visit, typeof(Interop.ObjObjFunc));
+            var visitFunc = NativeCall.GetDelegate<Interop.ObjObjFunc>(visit);
             return visitFunc(ob, arg);
         }
 
@@ -196,7 +196,7 @@ internal void CallTypeClear()
             {
                 return;
             }
-            var clearFunc = (Interop.InquiryFunc)Marshal.GetDelegateForFunctionPointer(clearPtr, typeof(Interop.InquiryFunc));
+            var clearFunc = NativeCall.GetDelegate<Interop.InquiryFunc>(clearPtr);
             clearFunc(pyHandle);
         }
 
@@ -214,7 +214,8 @@ internal void CallTypeTraverse(Interop.ObjObjFunc visitproc, IntPtr arg)
             {
                 return;
             }
-            var traverseFunc = (Interop.ObjObjArgFunc)Marshal.GetDelegateForFunctionPointer(traversePtr, typeof(Interop.ObjObjArgFunc));
+            var traverseFunc = NativeCall.GetDelegate<Interop.ObjObjArgFunc>(traversePtr);
+
             var visiPtr = Marshal.GetFunctionPointerForDelegate(visitproc);
             traverseFunc(pyHandle, visiPtr, arg);
         }
diff --git a/src/runtime/nativecall.cs b/src/runtime/nativecall.cs
@@ -40,10 +40,15 @@ public static int Int_Call_3(IntPtr fp, IntPtr a1, IntPtr a2, IntPtr a3)
             return d(a1, a2, a3);
         }
 
-        private static T GetDelegate<T>(IntPtr fp) where T: Delegate
+        internal static T GetDelegate<T>(IntPtr fp) where T: Delegate
         {
-            // Use Marshal.GetDelegateForFunctionPointer<> directly after upgrade the framework
-            return (T)Marshal.GetDelegateForFunctionPointer(fp, typeof(T));
+            Delegate d = null;
+            if (!Interop.allocatedThunks.TryGetValue(fp, out d))
+            {
+                // Use Marshal.GetDelegateForFunctionPointer<> directly after upgrade the framework
+                d = Marshal.GetDelegateForFunctionPointer(fp, typeof(T));
+            }
+            return (T)d;
         }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -491,6 +491,9 @@ internal static Type GetPrototype(string name)`
`491`	`491`	`return pmap[name] as Type;`
`492`	`492`	`}`
`493`	`493`
	`494`	`+`
	`495`	`+ internal static Dictionary<IntPtr, Delegate> allocatedThunks = new Dictionary<IntPtr, Delegate>();`
	`496`	`+`
`494`	`497`	`internal static ThunkInfo GetThunk(MethodInfo method, string funcType = null)`
`495`	`498`	`{`
`496`	`499`	`Type dt;`
`@@ -505,6 +508,7 @@ internal static ThunkInfo GetThunk(MethodInfo method, string funcType = null)`
`505`	`508`	`}`
`506`	`509`	`Delegate d = Delegate.CreateDelegate(dt, method);`
`507`	`510`	`var info = new ThunkInfo(d);`
	`511`	`+ allocatedThunks[info.Address] = d;`
`508`	`512`	`return info;`
`509`	`513`	`}`
`510`	`514`
Original file line number	Diff line number	Diff line change
`@@ -178,7 +178,7 @@ internal static int PyVisit(IntPtr ob, IntPtr visit, IntPtr arg)`
`178`	`178`	`{`
`179`	`179`	`return 0;`
`180`	`180`	`}`
`181`		`- var visitFunc = (Interop.ObjObjFunc)Marshal.GetDelegateForFunctionPointer(visit, typeof(Interop.ObjObjFunc));`
	`181`	`+ var visitFunc = NativeCall.GetDelegate<Interop.ObjObjFunc>(visit);`
`182`	`182`	`return visitFunc(ob, arg);`
`183`	`183`	`}`
`184`	`184`
`@@ -196,7 +196,7 @@ internal void CallTypeClear()`
`196`	`196`	`{`
`197`	`197`	`return;`
`198`	`198`	`}`
`199`		`- var clearFunc = (Interop.InquiryFunc)Marshal.GetDelegateForFunctionPointer(clearPtr, typeof(Interop.InquiryFunc));`
	`199`	`+ var clearFunc = NativeCall.GetDelegate<Interop.InquiryFunc>(clearPtr);`
`200`	`200`	`clearFunc(pyHandle);`
`201`	`201`	`}`
`202`	`202`
`@@ -214,7 +214,8 @@ internal void CallTypeTraverse(Interop.ObjObjFunc visitproc, IntPtr arg)`
`214`	`214`	`{`
`215`	`215`	`return;`
`216`	`216`	`}`
`217`		`- var traverseFunc = (Interop.ObjObjArgFunc)Marshal.GetDelegateForFunctionPointer(traversePtr, typeof(Interop.ObjObjArgFunc));`
	`217`	`+ var traverseFunc = NativeCall.GetDelegate<Interop.ObjObjArgFunc>(traversePtr);`
	`218`	`+`
`218`	`219`	`var visiPtr = Marshal.GetFunctionPointerForDelegate(visitproc);`
`219`	`220`	`traverseFunc(pyHandle, visiPtr, arg);`
`220`	`221`	`}`
Original file line number	Diff line number	Diff line change
`@@ -40,10 +40,15 @@ public static int Int_Call_3(IntPtr fp, IntPtr a1, IntPtr a2, IntPtr a3)`
`40`	`40`	`return d(a1, a2, a3);`
`41`	`41`	`}`
`42`	`42`
`43`		`- private static T GetDelegate<T>(IntPtr fp) where T: Delegate`
	`43`	`+ internal static T GetDelegate<T>(IntPtr fp) where T: Delegate`
`44`	`44`	`{`
`45`		`- // Use Marshal.GetDelegateForFunctionPointer<> directly after upgrade the framework`
`46`		`- return (T)Marshal.GetDelegateForFunctionPointer(fp, typeof(T));`
	`45`	`+ Delegate d = null;`
	`46`	`+ if (!Interop.allocatedThunks.TryGetValue(fp, out d))`
	`47`	`+ {`
	`48`	`+ // Use Marshal.GetDelegateForFunctionPointer<> directly after upgrade the framework`
	`49`	`+ d = Marshal.GetDelegateForFunctionPointer(fp, typeof(T));`
	`50`	`+ }`
	`51`	`+ return (T)d;`
`47`	`52`	`}`
`48`	`53`	`}`
`49`	`54`	`}`