Use 'auto' with 'new' expressions

For variable declarations initialized with new expressions, use 'auto' for the
type specifier.

The 'auto' replacement happens only when the type of the VarDecl exactly
matches the type of the initializer and the VarDecl is *not* CV-qualified. The
only case that is currently handled is if the pointer type of the VarDecl is
itself CV qualified.

Some improvements need to be made to Clang's TypeLoc information in order for
other CV qualifier cases to be successfully handled. See the new test suite
new_cv_failing.cpp for examples of usages that could be handled with such an
improvement.

Function pointers are, for now, not transformed until the identifier info can
be extracted.

Reviewer: klimek
llvm-svn: 178575

1 files changed, 32 insertions, 3 deletions

diff --git a/clang-tools-extra/cpp11-migrate/UseAuto/UseAutoMatchers.cpp b/clang-tools-extra/cpp11-migrate/UseAuto/UseAutoMatchers.cpp
index b17708eabd4..08f9a7e52f6 100644
--- a/clang-tools-extra/cpp11-migrate/UseAuto/UseAutoMatchers.cpp
+++ b/clang-tools-extra/cpp11-migrate/UseAuto/UseAutoMatchers.cpp
@@ -18,7 +18,9 @@
 using namespace clang::ast_matchers;
 using namespace clang;
 
-const char *DeclNodeId = "decl";
+const char *IteratorDeclId = "iterator_decl";
+const char *DeclWithNewId = "decl_new";
+const char *NewExprId = "new_expr";
 
 namespace clang {
 namespace ast_matchers {
@@ -230,7 +232,7 @@ TypeMatcher iteratorFromUsingDeclaration() {
 }
 } // namespace
 
-DeclarationMatcher makeIteratorMatcher() {
+DeclarationMatcher makeIteratorDeclMatcher() {
   return varDecl(allOf(
                    hasWrittenNonListInitializer(),
                    unless(hasType(autoType())),
@@ -243,5 +245,32 @@ DeclarationMatcher makeIteratorMatcher() {
                        )
                      )
                    )
-                 )).bind(DeclNodeId);
+                 )).bind(IteratorDeclId);
+}
+
+DeclarationMatcher makeDeclWithNewMatcher() {
+  return varDecl(
+           hasInitializer(
+             ignoringParenImpCasts(
+               newExpr().bind(NewExprId)
+             )
+           ),
+
+           // FIXME: TypeLoc information is not reliable where CV qualifiers are
+           // concerned so these types can't be handled for now.
+           unless(hasType(pointerType(pointee(hasLocalQualifiers())))),
+
+           // FIXME: Handle function pointers. For now we ignore them because
+           // the replacement replaces the entire type specifier source range
+           // which includes the identifier.
+           unless(
+             hasType(
+               pointsTo(
+                 pointsTo(
+                   parenType(innerType(functionType()))
+                 )
+               )
+             )
+           )
+         ).bind(DeclWithNewId);
 }