Rename cpp11-migrate to clang-modernize.

There is no reason to expect this tool to be limited to C++11, it seems
very likely to be of on-going interest. It seems likely to be useful for
modernizing even as new libraries come out in TSes and other formats
than a complete standard. Fundamentally, we need something a bit more
general. After some discussion on the list, going with
'clang-modernize'.

I've tried to do a reasonably comprehensive job of fixing up the names,
but I may still have missed some. Feel free to poke me if you spot any
fallout here. Things I've tried reasonably hard to find and fix:

- cpp11-migrate -> clang-modernize
- Migrator -> Modernizer
- Clean up the introductory documentation that was C++11 specific.

I'll also point out that this tool continues to delight me. =] Also,
a huge thanks to those who have so carefully, thoroughly documented the
tool. The docs here are simply phenomenal. Every tool should be this
well documented. I hope I have updated the documentation reasonably
well, but I'm not very good at documentation, so review much
appreciated.

llvm-svn: 189960

1 files changed, 70 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-modernize/UseNullptr/NullptrMatchers.cpp b/clang-tools-extra/clang-modernize/UseNullptr/NullptrMatchers.cpp
new file mode 100644
index 00000000000..0995c168b50
--- /dev/null
+++ b/clang-tools-extra/clang-modernize/UseNullptr/NullptrMatchers.cpp
@@ -0,0 +1,70 @@
+//===-- UseNullptr/NullptrMatchers.cpp - Matchers for null casts ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file contains the definitions for matcher-generating functions
+/// and a custom AST_MATCHER for identifying casts of type CK_NullTo*.
+///
+//===----------------------------------------------------------------------===//
+
+#include "NullptrMatchers.h"
+#include "clang/AST/ASTContext.h"
+
+using namespace clang::ast_matchers;
+using namespace clang;
+
+const char *CastSequence = "sequence";
+
+namespace clang {
+namespace ast_matchers {
+/// \brief Matches cast expressions that have a cast kind of CK_NullToPointer
+/// or CK_NullToMemberPointer.
+///
+/// Given
+/// \code
+///   int *p = 0;
+/// \endcode
+/// implicitCastExpr(isNullToPointer()) matches the implicit cast clang adds
+/// around \c 0.
+AST_MATCHER(CastExpr, isNullToPointer) {
+  return Node.getCastKind() == CK_NullToPointer ||
+    Node.getCastKind() == CK_NullToMemberPointer;
+}
+
+AST_MATCHER(Type, sugaredNullptrType) {
+  const Type *DesugaredType = Node.getUnqualifiedDesugaredType();
+  if (const BuiltinType *BT = dyn_cast<BuiltinType>(DesugaredType))
+    return BT->getKind() == BuiltinType::NullPtr;
+  return false;
+}
+
+} // end namespace ast_matchers
+} // end namespace clang
+
+StatementMatcher makeCastSequenceMatcher() {
+  StatementMatcher ImplicitCastToNull =
+    implicitCastExpr(
+      isNullToPointer(),
+      unless(
+        hasSourceExpression(
+          hasType(sugaredNullptrType())
+        )
+      )
+    );
+
+  return castExpr(
+           anyOf(
+             ImplicitCastToNull,
+             explicitCastExpr(
+               hasDescendant(ImplicitCastToNull)
+             )
+           ),
+           unless(hasAncestor(explicitCastExpr()))
+         ).bind(CastSequence);
+}