[libclang] Only mark CXCursors for explicit attributes with a type

All attributes have a source range associated with it. However, implicit
attributes are added by the compiler, and not added because the user
wrote something in the input. So no token type should be set to
CXCursor_*Attr.

The problem was visible when a class gets marked by e.g.
MSInheritanceAttr, which has the full CXXRecordDecl's range as its
own range. The effect of marking that range as CXCursor_UnexposedAttr
was that all cursors for the record decl, including all child decls,
would become CXCursor_UnexposedAttr.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@330692 91177308-0d34-0410-b5e6-96231b3b80d8

test/Index/annotate-tokens-unexposed.cpp

@@ -0,0 +1,20 @@
+// RUN: c-index-test -test-annotate-tokens=%s:1:1:16:1 %s -target x86_64-pc-windows-msvc | FileCheck %s
+class Foo
+{
+public:
+    void step(int v);
+    Foo();
+};
+
+void bar()
+{
+    // Introduce a MSInheritanceAttr node on the CXXRecordDecl for Foo. The
+    // existance of this attribute should not mark all cursors for tokens in
+    // Foo as UnexposedAttr.
+    &Foo::step;
+}
+
+Foo::Foo()
+{}
+
+// CHECK-NOT: UnexposedAttr=

tools/libclang/CIndex.cpp

@@ -1796,7 +1796,7 @@ bool CursorVisitor::VisitCXXRecordDecl(CXXRecordDecl *D) {
 
 bool CursorVisitor::VisitAttributes(Decl *D) {
   for (const auto *I : D->attrs())
-    if (Visit(MakeCXCursor(I, D, TU)))
+    if (!I->isImplicit() && Visit(MakeCXCursor(I, D, TU)))
         return true;
 
   return false;