A step towards sorting out handling of triviality of special members in C++11.

Separate out the notions of 'has a trivial special member' and 'has a
non-trivial special member', and use them appropriately. These are not
opposites of one another (there might be no special member, or in C++11 there
might be a trivial one and a non-trivial one). The CXXRecordDecl predicates
continue to produce incorrect results, but do so in fewer cases now, and
they document the cases where they might be wrong.

No functionality changes are intended here (they will come when the predicates
start producing the right answers...).

llvm-svn: 168119

1 files changed, 22 insertions, 13 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 72516fda80c..cc19ce99596 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9735,13 +9735,18 @@ bool Sema::CheckNontrivialField(FieldDecl *FD) {
       // copy constructors.
 
       CXXSpecialMember member = CXXInvalid;
-      if (!RDecl->hasTrivialCopyConstructor())
+      // We're required to check for any non-trivial constructors. Since the
+      // implicit default constructor is suppressed if there are any
+      // user-declared constructors, we just need to check that there is a
+      // trivial default constructor and a trivial copy constructor. (We don't
+      // worry about move constructors here, since this is a C++98 check.)
+      if (RDecl->hasNonTrivialCopyConstructor())
         member = CXXCopyConstructor;
       else if (!RDecl->hasTrivialDefaultConstructor())
         member = CXXDefaultConstructor;
-      else if (!RDecl->hasTrivialCopyAssignment())
+      else if (RDecl->hasNonTrivialCopyAssignment())
         member = CXXCopyAssignment;
-      else if (!RDecl->hasTrivialDestructor())
+      else if (RDecl->hasNonTrivialDestructor())
         member = CXXDestructor;
 
       if (member != CXXInvalid) {
@@ -9789,6 +9794,8 @@ static bool diagnoseNonTrivialUserDeclaredCtor(Sema &S, QualType QT,
 
 /// DiagnoseNontrivial - Given that a class has a non-trivial
 /// special member, figure out why.
+/// FIXME: These checks are not correct in C++11 mode. Currently, this is OK
+/// since we only use this in C++11 for a -Wc++98-compat warning.
 void Sema::DiagnoseNontrivial(const RecordType* T, CXXSpecialMember member) {
   QualType QT(T, 0U);
   CXXRecordDecl* RD = cast<CXXRecordDecl>(T->getDecl());
@@ -9887,17 +9894,21 @@ void Sema::DiagnoseNontrivial(const RecordType* T, CXXSpecialMember member) {
     }
   }
 
-  bool (CXXRecordDecl::*hasTrivial)() const;
+  bool (CXXRecordDecl::*hasNonTrivial)() const;
   switch (member) {
   case CXXDefaultConstructor:
-    hasTrivial = &CXXRecordDecl::hasTrivialDefaultConstructor; break;
+    hasNonTrivial = &CXXRecordDecl::hasNonTrivialDefaultConstructor; break;
   case CXXCopyConstructor:
-    hasTrivial = &CXXRecordDecl::hasTrivialCopyConstructor; break;
+    hasNonTrivial = &CXXRecordDecl::hasNonTrivialCopyConstructor; break;
   case CXXCopyAssignment:
-    hasTrivial = &CXXRecordDecl::hasTrivialCopyAssignment; break;
+    hasNonTrivial = &CXXRecordDecl::hasNonTrivialCopyAssignment; break;
+  case CXXMoveConstructor:
+    hasNonTrivial = &CXXRecordDecl::hasNonTrivialMoveConstructor; break;
+  case CXXMoveAssignment:
+    hasNonTrivial = &CXXRecordDecl::hasNonTrivialMoveAssignment; break;
   case CXXDestructor:
-    hasTrivial = &CXXRecordDecl::hasTrivialDestructor; break;
-  default:
+    hasNonTrivial = &CXXRecordDecl::hasNonTrivialDestructor; break;
+  case CXXInvalid:
     llvm_unreachable("unexpected special member");
   }
 
@@ -9906,7 +9917,7 @@ void Sema::DiagnoseNontrivial(const RecordType* T, CXXSpecialMember member) {
     const RecordType *BaseRT = bi->getType()->getAs<RecordType>();
     assert(BaseRT && "Don't know how to handle dependent bases");
     CXXRecordDecl *BaseRecTy = cast<CXXRecordDecl>(BaseRT->getDecl());
-    if (!(BaseRecTy->*hasTrivial)()) {
+    if ((BaseRecTy->*hasNonTrivial)()) {
       SourceLocation BaseLoc = bi->getLocStart();
       Diag(BaseLoc, diag::note_nontrivial_has_nontrivial) << QT << 1 << member;
       DiagnoseNontrivial(BaseRT, member);
@@ -9922,7 +9933,7 @@ void Sema::DiagnoseNontrivial(const RecordType* T, CXXSpecialMember member) {
     if (const RecordType *EltRT = EltTy->getAs<RecordType>()) {
       CXXRecordDecl* EltRD = cast<CXXRecordDecl>(EltRT->getDecl());
 
-      if (!(EltRD->*hasTrivial)()) {
+      if ((EltRD->*hasNonTrivial)()) {
         SourceLocation FLoc = fi->getLocation();
         Diag(FLoc, diag::note_nontrivial_has_nontrivial) << QT << 0 << member;
         DiagnoseNontrivial(EltRT, member);
@@ -9945,8 +9956,6 @@ void Sema::DiagnoseNontrivial(const RecordType* T, CXXSpecialMember member) {
       }
     }
   }
-
-  llvm_unreachable("found no explanation for non-trivial member");
 }
 
 /// TranslateIvarVisibility - Translate visibility from a token ID to an