[silgen] Fix deallocating destructor emission to begin a borrow scope around the class's call to its destroying destructor.

Author: gottesmm

lib/SILGen/SILGenDestructor.cpp

@@ -12,6 +12,7 @@
 
 #include "SILGenFunction.h"
 #include "RValue.h"
+#include "Scope.h"
 #include "swift/AST/AST.h"
 #include "swift/SIL/TypeLowering.h"
 
@@ -96,9 +97,13 @@ void SILGenFunction::emitDeallocatingDestructor(DestructorDecl *dd) {
     = emitSiblingMethodRef(loc, selfValue, dtorConstant, subs);
 
   // Call the destroying destructor.
-  SILType objectPtrTy = SILType::getNativeObjectType(F.getASTContext());
-  selfValue = B.createApply(loc, dtorValue.forward(*this),
-                            dtorTy, objectPtrTy, subs, selfValue);
+  {
+    FullExpr CleanupScope(Cleanups, CleanupLocation::get(loc));
+    ManagedValue borrowedSelf = emitManagedBeginBorrow(loc, selfValue);
+    SILType objectPtrTy = SILType::getNativeObjectType(F.getASTContext());
+    selfValue = B.createApply(loc, dtorValue.forward(*this),
+                              dtorTy, objectPtrTy, subs, borrowedSelf.getUnmanagedValue());
+  }
 
   // Deallocate the object.
   selfValue = B.createUncheckedRefCast(loc, selfValue, classTy);

test/SILGen/lifetime.swift

@@ -527,7 +527,9 @@ class Foo<T> {
   // CHECK-LABEL: sil hidden @_T08lifetime3FooCfD : $@convention(method) <T> (@owned Foo<T>) -> ()
   // CHECK: bb0([[SELF:%[0-9]+]] : $Foo<T>):
   // CHECK:   [[DESTROYING_REF:%[0-9]+]] = function_ref @_T08lifetime3FooCfd : $@convention(method) <τ_0_0> (@guaranteed Foo<τ_0_0>) -> @owned Builtin.NativeObject
-  // CHECK-NEXT:   [[RESULT_SELF:%[0-9]+]] = apply [[DESTROYING_REF]]<T>([[SELF]]) : $@convention(method) <τ_0_0> (@guaranteed Foo<τ_0_0>) -> @owned Builtin.NativeObject
+  // CHECK-NEXT:   [[BORROWED_SELF:%.*]] = begin_borrow [[SELF]]
+  // CHECK-NEXT:   [[RESULT_SELF:%[0-9]+]] = apply [[DESTROYING_REF]]<T>([[BORROWED_SELF]]) : $@convention(method) <τ_0_0> (@guaranteed Foo<τ_0_0>) -> @owned Builtin.NativeObject
+  // CHECK-NEXT:   end_borrow [[BORROWED_SELF]] from [[SELF]]
   // CHECK-NEXT:   [[SELF:%[0-9]+]] = unchecked_ref_cast [[RESULT_SELF]] : $Builtin.NativeObject to $Foo<T>
   // CHECK-NEXT:   dealloc_ref [[SELF]] : $Foo<T>
   // CHECK-NEXT:   [[RESULT:%[0-9]+]] = tuple ()