Remove CXXRecordDecl flags which are unused after r158289.

We need an efficient mechanism to determine whether a defaulted default
constructor is constexpr, in order to determine whether a class is a literal
type, so keep the incrementally-built form on CXXRecordDecl. Remove the
on-demand computation of same, so that we only have one method for determining
whether a default constructor is constexpr. This doesn't affect correctness,
since default constructor lookup is much simpler than selecting a constructor
for copying or moving.

We don't need a corresponding mechanism for defaulted copy or move constructors,
since they can't affect whether a type is a literal type. Conversely, checking
whether such functions are constexpr can require non-trivial effort, so we defer
such checks until the copy or move constructor is required.

Thus we now only compute whether a copy or move constructor is constexpr on
demand, and only compute whether a default constructor is constexpr in advance.
This is unfortunate, but seems like the best solution.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158290 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 6 insertions, 76 deletions

diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index d8550eb0f2..bc139207ce 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -1858,14 +1858,8 @@ bool ASTNodeImporter::ImportDefinition(RecordDecl *From, RecordDecl *To,
       = FromData.HasConstexprNonCopyMoveConstructor;
     ToData.DefaultedDefaultConstructorIsConstexpr
       = FromData.DefaultedDefaultConstructorIsConstexpr;
-    ToData.DefaultedCopyConstructorIsConstexpr
-      = FromData.DefaultedCopyConstructorIsConstexpr;
-    ToData.DefaultedMoveConstructorIsConstexpr
-      = FromData.DefaultedMoveConstructorIsConstexpr;
     ToData.HasConstexprDefaultConstructor
       = FromData.HasConstexprDefaultConstructor;
-    ToData.HasConstexprCopyConstructor = FromData.HasConstexprCopyConstructor;
-    ToData.HasConstexprMoveConstructor = FromData.HasConstexprMoveConstructor;
     ToData.HasTrivialCopyConstructor = FromData.HasTrivialCopyConstructor;
     ToData.HasTrivialMoveConstructor = FromData.HasTrivialMoveConstructor;
     ToData.HasTrivialCopyAssignment = FromData.HasTrivialCopyAssignment;
diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 84aa7c5c88..0e28a5e7dd 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -47,10 +47,7 @@ CXXRecordDecl::DefinitionData::DefinitionData(CXXRecordDecl *D)
     HasTrivialDefaultConstructor(true),
     HasConstexprNonCopyMoveConstructor(false),
     DefaultedDefaultConstructorIsConstexpr(true),
-    DefaultedCopyConstructorIsConstexpr(true),
-    DefaultedMoveConstructorIsConstexpr(true),
-    HasConstexprDefaultConstructor(false), HasConstexprCopyConstructor(false),
-    HasConstexprMoveConstructor(false), HasTrivialCopyConstructor(true),
+    HasConstexprDefaultConstructor(false), HasTrivialCopyConstructor(true),
     HasTrivialMoveConstructor(true), HasTrivialCopyAssignment(true),
     HasTrivialMoveAssignment(true), HasTrivialDestructor(true),
     HasIrrelevantDestructor(true),
@@ -220,8 +217,6 @@ CXXRecordDecl::setBases(CXXBaseSpecifier const * const *Bases,
       //   In the definition of a constexpr constructor [...]
       //    -- the class shall not have any virtual base classes
       data().DefaultedDefaultConstructorIsConstexpr = false;
-      data().DefaultedCopyConstructorIsConstexpr = false;
-      data().DefaultedMoveConstructorIsConstexpr = false;
     } else {
       // C++ [class.ctor]p5:
       //   A default constructor is trivial [...] if:
@@ -260,25 +255,6 @@ CXXRecordDecl::setBases(CXXBaseSpecifier const * const *Bases,
       //   default constructor is constexpr.
       if (!BaseClassDecl->hasConstexprDefaultConstructor())
         data().DefaultedDefaultConstructorIsConstexpr = false;
-
-      // C++11 [class.copy]p13:
-      //   If the implicitly-defined constructor would satisfy the requirements
-      //   of a constexpr constructor, the implicitly-defined constructor is
-      //   constexpr.
-      // C++11 [dcl.constexpr]p4:
-      //    -- every constructor involved in initializing [...] base class
-      //       sub-objects shall be a constexpr constructor
-      if (!BaseClassDecl->hasConstexprCopyConstructor())
-        data().DefaultedCopyConstructorIsConstexpr = false;
-      if (BaseClassDecl->hasDeclaredMoveConstructor() ||
-          BaseClassDecl->needsImplicitMoveConstructor())
-        // FIXME: If the implicit move constructor generated for the base class
-        // would be ill-formed, the implicit move constructor generated for the
-        // derived class calls the base class' copy constructor.
-        data().DefaultedMoveConstructorIsConstexpr &=
-          BaseClassDecl->hasConstexprMoveConstructor();
-      else if (!BaseClassDecl->hasConstexprCopyConstructor())
-        data().DefaultedMoveConstructorIsConstexpr = false;
     }
     
     // C++ [class.ctor]p3:
@@ -471,11 +447,7 @@ void CXXRecordDecl::markedVirtualFunctionPure() {
 }
 
 void CXXRecordDecl::markedConstructorConstexpr(CXXConstructorDecl *CD) {
-  if (CD->isCopyConstructor())
-    data().HasConstexprCopyConstructor = true;
-  else if (CD->isMoveConstructor())
-    data().HasConstexprMoveConstructor = true;
-  else
+  if (!CD->isCopyOrMoveConstructor())
     data().HasConstexprNonCopyMoveConstructor = true;
 
   if (CD->isDefaultConstructor())
@@ -558,12 +530,8 @@ void CXXRecordDecl::addedMember(Decl *D) {
         }
       } else if (Constructor->isCopyConstructor()) {
         data().DeclaredCopyConstructor = true;
-        if (Constructor->isConstexpr())
-          data().HasConstexprCopyConstructor = true;
       } else if (Constructor->isMoveConstructor()) {
         data().DeclaredMoveConstructor = true;
-        if (Constructor->isConstexpr())
-          data().HasConstexprMoveConstructor = true;
       } else
         goto NotASpecialMember;
       return;
@@ -620,9 +588,6 @@ NotASpecialMember:;
         //   user-provided [...]
         if (UserProvided)
           data().HasTrivialCopyConstructor = false;
-
-        if (Constructor->isConstexpr())
-          data().HasConstexprCopyConstructor = true;
       } else if (Constructor->isMoveConstructor()) {
         data().UserDeclaredMoveConstructor = true;
         data().DeclaredMoveConstructor = true;
@@ -632,9 +597,6 @@ NotASpecialMember:;
         //   user-provided [...]
         if (UserProvided)
           data().HasTrivialMoveConstructor = false;
-
-        if (Constructor->isConstexpr())
-          data().HasConstexprMoveConstructor = true;
       }
     }
     if (Constructor->isConstexpr() && !Constructor->isCopyOrMoveConstructor()) {
@@ -676,19 +638,9 @@ NotASpecialMember:;
     // C++11 [class.dtor]p5: 
     //   A destructor is trivial if it is not user-provided and if
     //    -- the destructor is not virtual.
-    if (DD->isUserProvided() || DD->isVirtual()) {
+    if (DD->isUserProvided() || DD->isVirtual())
       data().HasTrivialDestructor = false;
-      // C++11 [dcl.constexpr]p1:
-      //   The constexpr specifier shall be applied only to [...] the
-      //   declaration of a static data member of a literal type.
-      // C++11 [basic.types]p10:
-      //   A type is a literal type if it is [...] a class type that [...] has
-      //   a trivial destructor.
-      data().DefaultedDefaultConstructorIsConstexpr = false;
-      data().DefaultedCopyConstructorIsConstexpr = false;
-      data().DefaultedMoveConstructorIsConstexpr = false;
-    }
-    
+
     return;
   }
   
@@ -939,27 +891,11 @@ NotASpecialMember:;
           // The standard requires any in-class initializer to be a constant
           // expression. We consider this to be a defect.
           data().DefaultedDefaultConstructorIsConstexpr = false;
-
-        if (!FieldRec->hasConstexprCopyConstructor())
-          data().DefaultedCopyConstructorIsConstexpr = false;
-
-        if (FieldRec->hasDeclaredMoveConstructor() ||
-            FieldRec->needsImplicitMoveConstructor())
-          // FIXME: If the implicit move constructor generated for the member's
-          // class would be ill-formed, the implicit move constructor generated
-          // for this class calls the member's copy constructor.
-          data().DefaultedMoveConstructorIsConstexpr &=
-            FieldRec->hasConstexprMoveConstructor();
-        else if (!FieldRec->hasConstexprCopyConstructor())
-          data().DefaultedMoveConstructorIsConstexpr = false;
       }
     } else {
       // Base element type of field is a non-class type.
-      if (!T->isLiteralType()) {
-        data().DefaultedDefaultConstructorIsConstexpr = false;
-        data().DefaultedCopyConstructorIsConstexpr = false;
-        data().DefaultedMoveConstructorIsConstexpr = false;
-      } else if (!Field->hasInClassInitializer() && !isUnion())
+      if (!T->isLiteralType() ||
+          (!Field->hasInClassInitializer() && !isUnion()))
         data().DefaultedDefaultConstructorIsConstexpr = false;
     }