[msr] Handle IntPtr.Zero correctly.

xamarin · Aug 10, 2023 · 38771ad · 38771ad
1 parent 4b16a0f
commit 38771ad
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diff --git a/tools/dotnet-linker/AppBundleRewriter.cs b/tools/dotnet-linker/AppBundleRewriter.cs
@@ -236,6 +236,12 @@ public TypeReference System_IntPtr {
 			}
 		}
 
+		public FieldReference System_IntPtr_Zero {
+			get {
+				return GetFieldReference (CorlibAssembly, System_IntPtr, "Zero", "System.IntPtr::Zero", out var _);
+			}
+		}
+
 		public TypeReference System_Nullable_1 {
 			get {
 				return GetTypeReference (CorlibAssembly, "System.Nullable`1", out var _);
@@ -1174,6 +1180,7 @@ public void ClearCurrentAssembly ()
 			current_assembly = null;
 			type_map.Clear ();
 			method_map.Clear ();
+			field_map.Clear ();
 		}
 
 		public CustomAttribute CreateDynamicDependencyAttribute (string memberSignature)

diff --git a/tools/dotnet-linker/Steps/ManagedRegistrarStep.cs b/tools/dotnet-linker/Steps/ManagedRegistrarStep.cs
@@ -929,11 +929,22 @@ bool EmitConversion (MethodDefinition method, ILProcessor il, TypeReference type
 						var loadHandle = il.Create (OpCodes.Ldloc, tmpVariable);
 						var done = il.Create (OpCodes.Nop);
 						il.Emit (OpCodes.Stloc, tmpVariable);
+						// objectVariable = null
+						il.Emit (OpCodes.Ldnull);
+						il.Emit (OpCodes.Stloc, objectVariable);
+						// if (handle == IntPtr.Zero)
+						//     goto done;
+						il.Emit (OpCodes.Ldloc, tmpVariable); // handle
+						il.Emit (OpCodes.Ldsfld, abr.System_IntPtr_Zero);
+						il.Emit (OpCodes.Beq, done);
+						// objectVariable = TryGetNSObject (handle, false) as TargetType
 						il.Emit (OpCodes.Ldloc, tmpVariable); // handle
 						il.Emit (OpCodes.Ldc_I4_0); // false
 						il.Emit (OpCodes.Call, abr.Runtime_TryGetNSObject);
 						il.Emit (OpCodes.Castclass, targetType);
 						il.Emit (OpCodes.Stloc, objectVariable);
+						// if (objectVariable is null)
+						//     objectVariable = new TargetType (handle, false)
 						il.Emit (OpCodes.Ldloc, objectVariable);
 						il.Emit (OpCodes.Brfalse, loadHandle);
 						il.Emit (OpCodes.Br, done);
@@ -943,6 +954,8 @@ bool EmitConversion (MethodDefinition method, ILProcessor il, TypeReference type
 						il.Emit (OpCodes.Ldc_I4_0); // false
 						il.Emit (OpCodes.Newobj, method.Module.ImportReference (ctor));
 						il.Emit (OpCodes.Stloc, objectVariable);
+						// done:
+						// (load objectVariable on the stack)
 						il.Append (done);
 						il.Emit (OpCodes.Ldloc, objectVariable);
 					}