Implement a new type trait __is_trivially_constructible(T, Args...)
that provides the behavior of the C++11 library trait
std::is_trivially_constructible<T, Args...>, which can't be
implemented purely as a library.

Since __is_trivially_constructible can have zero or more arguments, I
needed to add Yet Another Type Trait Expression Class, this one
handling arbitrary arguments. The next step will be to migrate
UnaryTypeTrait and BinaryTypeTrait over to this new, more general
TypeTrait class.

Fixes the Clang side of <rdar://problem/10895483> / PR12038.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151352 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 8d0f5fa..53c7634 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -1755,6 +1755,7 @@
   void VisitWhileStmt(WhileStmt *W);
   void VisitUnaryTypeTraitExpr(UnaryTypeTraitExpr *E);
   void VisitBinaryTypeTraitExpr(BinaryTypeTraitExpr *E);
+  void VisitTypeTraitExpr(TypeTraitExpr *E);
   void VisitArrayTypeTraitExpr(ArrayTypeTraitExpr *E);
   void VisitExpressionTraitExpr(ExpressionTraitExpr *E);
   void VisitUnresolvedMemberExpr(UnresolvedMemberExpr *U);
@@ -2056,6 +2057,11 @@
   AddTypeLoc(E->getLhsTypeSourceInfo());
 }
 
+void EnqueueVisitor::VisitTypeTraitExpr(TypeTraitExpr *E) {
+  for (unsigned I = E->getNumArgs(); I > 0; --I)
+    AddTypeLoc(E->getArg(I-1));
+}
+
 void EnqueueVisitor::VisitArrayTypeTraitExpr(ArrayTypeTraitExpr *E) {
   AddTypeLoc(E->getQueriedTypeSourceInfo());
 }