Merge pull request #78008 from swiftlang/fix-definit-init-6.1

[6.1] DefiniteInitialization: correctly handle upcasts in delegating initializers

Author: eeckstein

lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp

@@ -2741,6 +2741,12 @@ void LifetimeChecker::processUninitializedRelease(SILInstruction *Release,
     if (Pointer->getType().isAddress())
       Pointer = B.createLoad(Loc, Pointer, LoadOwnershipQualifier::Take);
 
+    // Cast back down from an upcast.
+    if (auto *UI = dyn_cast<UpcastInst>(Pointer)) {
+      Pointer =
+          B.createUncheckedRefCast(Loc, Pointer, UI->getOperand()->getType());
+    }
+
     auto MetatypeTy = CanMetatypeType::get(TheMemory.getASTType(),
                                            MetatypeRepresentation::Thick);
     auto SILMetatypeTy = SILType::getPrimitiveObjectType(MetatypeTy);
@@ -2763,12 +2769,6 @@ void LifetimeChecker::processUninitializedRelease(SILInstruction *Release,
       }
     }
 
-    // Cast back down from an upcast.
-    if (auto *UI = dyn_cast<UpcastInst>(Pointer)) {
-      Pointer =
-          B.createUncheckedRefCast(Loc, Pointer, UI->getOperand()->getType());
-    }
-
     // We've already destroyed any instance variables initialized by this
     // constructor, now destroy instance variables initialized by subclass
     // constructors that delegated to us, and finally free the memory.

test/SILOptimizer/definite_init_crashes_objc.sil

@@ -37,8 +37,8 @@ class Sub : Super {
 // CHECK:         switch_enum
 // CHECK-SAME:        case #Optional.none!enumelt: [[NONE:bb[0-9]+]]
 // CHECK:       [[NONE]]:
-// CHECK:         [[SUB_META_1:%[^,]+]] = metatype $@thick Sub.Type
 // CHECK:         [[SUB_1:%[^,]+]] = unchecked_ref_cast [[SUPER_1]] : $Super to $Sub
+// CHECK:         [[SUB_META_1:%[^,]+]] = metatype $@thick Sub.Type
 // CHECK:         dealloc_partial_ref
 // CHECK-SAME:        [[SUB_1]]
 // CHECK-SAME:        [[SUB_META_1]]

test/SILOptimizer/definite_init_markuninitialized_delegatingself.sil

@@ -148,6 +148,31 @@ bb0(%0 : @owned $DerivedClassWithNontrivialStoredProperties):
   return %13 : $()
 }
 
+// CHECK-LABEL: sil [ossa] @test_delegating_derived_with_upcast :
+// CHECK:       bb0([[ARG:%.*]] : @owned $DerivedClassWithNontrivialStoredProperties):
+// CHECK-NEXT:    [[SELFBOX:%[0-9]+]] = alloc_stack $DerivedClassWithNontrivialStoredProperties
+// CHECK-NEXT:    store [[ARG]] to [init] [[SELFBOX]]
+// CHECK-NEXT:    [[SELF:%[0-9]+]] = load [take] [[SELFBOX]]
+// CHECK-NEXT:    [[UC:%[0-9]+]] = upcast [[SELF]]
+// CHECK-NEXT:    [[DC:%[0-9]+]] = unchecked_ref_cast [[UC]]
+// CHECK-NEXT:    [[METATYPE:%[0-9]+]] = value_metatype $@thick DerivedClassWithNontrivialStoredProperties.Type, [[DC]] : $DerivedClassWithNontrivialStoredProperties
+// CHECK-NEXT:    dealloc_partial_ref [[DC]] : $DerivedClassWithNontrivialStoredProperties, [[METATYPE]] : $@thick DerivedClassWithNontrivialStoredProperties.Type
+// CHECK-NEXT:    dealloc_stack [[SELFBOX]]
+sil [ossa] @test_delegating_derived_with_upcast : $@convention(method) (@owned DerivedClassWithNontrivialStoredProperties) -> () {
+bb0(%0 : @owned $DerivedClassWithNontrivialStoredProperties):
+  %1 = alloc_stack $DerivedClassWithNontrivialStoredProperties
+  %2 = mark_uninitialized [delegatingselfallocated] %1 : $*DerivedClassWithNontrivialStoredProperties
+  store %0 to [init] %2 : $*DerivedClassWithNontrivialStoredProperties
+  %4 = load [take] %2 : $*DerivedClassWithNontrivialStoredProperties
+  %5 = upcast %4 : $DerivedClassWithNontrivialStoredProperties to $RootClassWithNontrivialStoredProperties
+
+  destroy_value %5 : $RootClassWithNontrivialStoredProperties
+  dealloc_stack %1 : $*DerivedClassWithNontrivialStoredProperties
+
+  %13 = tuple ()
+  return %13 : $()
+}
+
 // <rdar://problem/20608881> DI miscompiles this testcase into a memory leak
 struct MyStruct3 {
   @_hasStorage var c: C