Fix tracking of whether a destructor would be deleted.

I've been unable to find any cases whose behavior is actually changed by this,
but only because an implicitly deleted destructor also results in it being
impossible to have a trivial (non-deleted) copy constructor, which the place
where this really matters (choosing whether to pass a class in registers)
happens to also check.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@313948 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/DeclCXX.h b/include/clang/AST/DeclCXX.h
index e2391d785d9b55c6879d5702f71467bfd74b157c..d85ace9dda06bc50387f155e0b01749178a867bd 100644 (file)
--- a/include/clang/AST/DeclCXX.h
+++ b/include/clang/AST/DeclCXX.h
@@ -838,7 +838,10 @@ public:
 
   /// \brief \c true if a defaulted destructor for this class would be deleted.
   bool defaultedDestructorIsDeleted() const {
-    return !data().DefaultedDestructorIsDeleted;
+    assert((!needsOverloadResolutionForDestructor() ||
+            (data().DeclaredSpecialMembers & SMF_Destructor)) &&
+           "this property has not yet been computed by Sema");
+    return data().DefaultedDestructorIsDeleted;
   }
 
   /// \brief \c true if we know for sure that this class has a single,
@@ -985,6 +988,15 @@ public:
     data().DefaultedMoveConstructorIsDeleted = true;
   }
 
+  /// \brief Set that we attempted to declare an implicit destructor,
+  /// but overload resolution failed so we deleted it.
+  void setImplicitDestructorIsDeleted() {
+    assert((data().DefaultedDestructorIsDeleted ||
+            needsOverloadResolutionForDestructor()) &&
+           "destructor should not be deleted");
+    data().DefaultedDestructorIsDeleted = true;
+  }
+
   /// \brief Determine whether this class should get an implicit move
   /// constructor or if any existing special member function inhibits this.
   bool needsImplicitMoveConstructor() const {

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 063a0b262b2dce1a80db85e6aadacb8f2b684044..33f02c5b7f4bf27c2e47be44e4e905205afbfca8 100644 (file)
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -15119,8 +15119,10 @@ void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
     if (CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(Record)) {
       auto *Dtor = CXXRecord->getDestructor();
       if (Dtor && Dtor->isImplicit() &&
-          ShouldDeleteSpecialMember(Dtor, CXXDestructor))
+          ShouldDeleteSpecialMember(Dtor, CXXDestructor)) {
+        CXXRecord->setImplicitDestructorIsDeleted();
         SetDeclDeleted(Dtor, CXXRecord->getLocation());
+      }
     }
 
     if (Record->hasAttrs()) {

diff --git a/test/CXX/special/class.dtor/p5-implicit.cpp b/test/CXX/special/class.dtor/p5-implicit.cpp
new file mode 100644 (file)
index 0000000..703be15
--- /dev/null
+++ b/test/CXX/special/class.dtor/p5-implicit.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -std=c++11 %s -ast-dump | FileCheck %s
+
+struct A { ~A() = delete; };
+// CHECK-LABEL: CXXRecordDecl {{.*}} struct A
+// CHECK: Destructor trivial user_declared
+
+struct B : A {};
+// CHECK-LABEL: CXXRecordDecl {{.*}} struct B
+// CHECK: Destructor trivial needs_overload_resolution
+
+struct C : B {};
+// CHECK-LABEL: CXXRecordDecl {{.*}} struct C
+// CHECK: Destructor trivial needs_overload_resolution
+
+struct D { ~D(); };
+struct E : D {};
+union U {
+  E e;
+};
+// CHECK-LABEL: CXXRecordDecl {{.*}} union U
+// CHECK: Destructor non_trivial needs_implicit defaulted_is_deleted