improved handling of dict offset in object instances

lostmsu · lostmsu · commit 57525cd8934c · 2021-04-11T13:25:53.000-07:00
diff --git a/src/runtime/interop.cs b/src/runtime/interop.cs
@@ -185,7 +185,10 @@ public static int magic(IntPtr type)
 
         public static int TypeDictOffset(IntPtr type)
         {
-            return ManagedDataOffsets.DictOffset(type);
+            Debug.Assert(TypeOffset.tp_dictoffset > 0);
+            int dictOffset = Marshal.ReadInt32(type, TypeOffset.tp_dictoffset);
+            Debug.Assert(dictOffset == ManagedDataOffsets.DictOffset(type));
+            return dictOffset;
         }
 
         public static int Size(IntPtr pyType)
diff --git a/src/runtime/managedtype.cs b/src/runtime/managedtype.cs
@@ -260,13 +260,17 @@ protected static void ClearObjectDict(IntPtr ob)
         protected static IntPtr GetObjectDict(IntPtr ob)
         {
             IntPtr type = Runtime.PyObject_TYPE(ob);
-            return Marshal.ReadIntPtr(ob, ObjectOffset.TypeDictOffset(type));
+            int dictOffset = ObjectOffset.TypeDictOffset(type);
+            if (dictOffset == 0) return IntPtr.Zero;
+            return Marshal.ReadIntPtr(ob, dictOffset);
         }
 
         protected static void SetObjectDict(IntPtr ob, IntPtr value)
         {
             IntPtr type = Runtime.PyObject_TYPE(ob);
-            Marshal.WriteIntPtr(ob, ObjectOffset.TypeDictOffset(type), value);
+            int dictOffset = ObjectOffset.TypeDictOffset(type);
+            Debug.Assert(dictOffset > 0);
+            Marshal.WriteIntPtr(ob, dictOffset, value);
         }
     }
 }
diff --git a/src/runtime/typemanager.cs b/src/runtime/typemanager.cs
@@ -165,7 +165,7 @@ internal static IntPtr CreateType(Type impl)
             // Set tp_basicsize to the size of our managed instance objects.
             Marshal.WriteIntPtr(type, TypeOffset.tp_basicsize, (IntPtr)ob_size);
 
-            var offset = (IntPtr)ObjectOffset.TypeDictOffset(type);
+            var offset = (IntPtr)ManagedDataOffsets.DictOffset(type);
             Marshal.WriteIntPtr(type, TypeOffset.tp_dictoffset, offset);
 
             SlotsHolder slotsHolder = CreateSolotsHolder(type);

Original file line number	Diff line number	Diff line change
`@@ -185,7 +185,10 @@ public static int magic(IntPtr type)`
`185`	`185`
`186`	`186`	`public static int TypeDictOffset(IntPtr type)`
`187`	`187`	`{`
`188`		`- return ManagedDataOffsets.DictOffset(type);`
	`188`	`+ Debug.Assert(TypeOffset.tp_dictoffset > 0);`
	`189`	`+ int dictOffset = Marshal.ReadInt32(type, TypeOffset.tp_dictoffset);`
	`190`	`+ Debug.Assert(dictOffset == ManagedDataOffsets.DictOffset(type));`
	`191`	`+ return dictOffset;`
`189`	`192`	`}`
`190`	`193`
`191`	`194`	`public static int Size(IntPtr pyType)`
Original file line number	Diff line number	Diff line change
`@@ -260,13 +260,17 @@ protected static void ClearObjectDict(IntPtr ob)`
`260`	`260`	`protected static IntPtr GetObjectDict(IntPtr ob)`
`261`	`261`	`{`
`262`	`262`	`IntPtr type = Runtime.PyObject_TYPE(ob);`
`263`		`- return Marshal.ReadIntPtr(ob, ObjectOffset.TypeDictOffset(type));`
	`263`	`+ int dictOffset = ObjectOffset.TypeDictOffset(type);`
	`264`	`+ if (dictOffset == 0) return IntPtr.Zero;`
	`265`	`+ return Marshal.ReadIntPtr(ob, dictOffset);`
`264`	`266`	`}`
`265`	`267`
`266`	`268`	`protected static void SetObjectDict(IntPtr ob, IntPtr value)`
`267`	`269`	`{`
`268`	`270`	`IntPtr type = Runtime.PyObject_TYPE(ob);`
`269`		`- Marshal.WriteIntPtr(ob, ObjectOffset.TypeDictOffset(type), value);`
	`271`	`+ int dictOffset = ObjectOffset.TypeDictOffset(type);`
	`272`	`+ Debug.Assert(dictOffset > 0);`
	`273`	`+ Marshal.WriteIntPtr(ob, dictOffset, value);`
`270`	`274`	`}`
`271`	`275`	`}`
`272`	`276`	`}`