constexpr: semantic checking for constexpr functions and constructors. Based in

part on patches by Peter Collingbourne.

We diverge from the C++11 standard in a few areas, mostly related to checking
constexpr function declarations, and not just definitions. See WG21 paper
N3308=11-0078 for details.

Function invocation substitution is not available in this patch; constexpr
functions cannot yet be used from within constant expressions.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140926 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 22 deletions

diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 7471a3da5d..a2c6954d75 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -1134,29 +1134,19 @@ bool Type::isLiteralType() const {
     return true;
   //    -- a class type that has all of the following properties:
   if (const RecordType *RT = BaseTy->getAs<RecordType>()) {
+    //    -- a trivial destructor,
+    //    -- every constructor call and full-expression in the
+    //       brace-or-equal-initializers for non-static data members (if any)
+    //       is a constant expression,
+    //    -- it is an aggregate type or has at least one constexpr
+    //       constructor or constructor template that is not a copy or move
+    //       constructor, and
+    //    -- all non-static data members and base classes of literal types
+    //
+    // We resolve DR1361 by ignoring the second bullet.
     if (const CXXRecordDecl *ClassDecl =
-        dyn_cast<CXXRecordDecl>(RT->getDecl())) {
-      //    -- a trivial destructor,
-      if (!ClassDecl->hasTrivialDestructor())
-        return false;
-
-      //    -- every constructor call and full-expression in the
-      //       brace-or-equal-initializers for non-static data members (if any)
-      //       is a constant expression,
-      // We deliberately do not implement this restriction. It isn't necessary
-      // and doesn't make any sense.
-
-      //    -- it is an aggregate type or has at least one constexpr
-      //       constructor or constructor template that is not a copy or move
-      //       constructor, and
-      if (!ClassDecl->isAggregate() &&
-          !ClassDecl->hasConstexprNonCopyMoveConstructor())
-        return false;
-
-      //    -- all non-static data members and base classes of literal types
-      if (ClassDecl->hasNonLiteralTypeFieldsOrBases())
-        return false;
-    }
+        dyn_cast<CXXRecordDecl>(RT->getDecl()))
+      return ClassDecl->isLiteral();
 
     return true;
   }