c++: C++11 range-for and ovl/lkp_iterator

We can't use C++11 range-based 'for' over a tree directly, because we don't
know what kind of range we want to use it as.  I suppose in some cases we
could guess, but it seems better to tersely make it explicit.  This patch
adds range adaptors ovl_range and lkp_range for use as the range of a
range-for, e.g.

  for (tree fn : lkp_range (fns)) { ... }

This patch also removes the private copy ops from ovl_iterator; it's
necessary for range-for, and these are effectively C++ forward_iterators,
which allow copying, so I don't see a reason to prevent it.  A bit more
would need to be done to make them actually conform as C++11 forward
iterators, but I don't think we particularly want to #include <iterator>
yet.

gcc/cp/ChangeLog:

	* cp-tree.h (class ovl_iterator): Allow copying.  Add op==.
	(class ovl_range, class lkp_range): New.
	* call.c (build_op_call_1, add_candidates): Use them.
	(build_op_delete_call, has_trivial_copy_assign_p): Likewise.
	(has_trivial_copy_p): Likewise.
	* class.c (handle_using_decl, get_basefndecls): Likewise.
	(maybe_warn_about_overly_private_class): Likewise.
	(warn_hidden, add_implicitly_declared_members): Likewise.
	(check_methods, clone_constructors_and_destructors): Likewise.
	(type_has_user_nondefault_constructor): Likewise.

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 678e120a165ba19c54f895cae95560c913cef0ad..57bac05fe70bc5a73ff3223faadd033a00d06da4 100644 (file)
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -4914,10 +4914,8 @@ build_op_call_1 (tree obj, vec<tree, va_gc> **args, tsubst_flags_t complain)
          || TYPE_REFFN_P (totype)
          || (TYPE_REF_P (totype)
              && TYPE_PTRFN_P (TREE_TYPE (totype))))
-       for (ovl_iterator iter (TREE_VALUE (convs)); iter; ++iter)
+       for (tree fn : ovl_range (TREE_VALUE (convs)))
          {
-           tree fn = *iter;
-
            if (DECL_NONCONVERTING_P (fn))
              continue;
 
@@ -5981,10 +5979,8 @@ add_candidates (tree fns, tree first_arg, const vec<tree, va_gc> *args,
     which = non_templates;
 
  again:
-  for (lkp_iterator iter (fns); iter; ++iter)
+  for (tree fn : lkp_range (fns))
     {
-      fn = *iter;
-
       if (check_converting && DECL_NONCONVERTING_P (fn))
        continue;
       if (check_list_ctor && !is_list_ctor (fn))
@@ -7016,10 +7012,8 @@ build_op_delete_call (enum tree_code code, tree addr, tree size,
             the usual deallocation function, so we shouldn't complain
             about using the operator delete (void *, size_t).  */
          if (DECL_CLASS_SCOPE_P (fn))
-           for (lkp_iterator iter (MAYBE_BASELINK_FUNCTIONS (fns));
-                iter; ++iter)
+           for (tree elt : lkp_range (MAYBE_BASELINK_FUNCTIONS (fns)))
              {
-               tree elt = *iter;
                if (usual_deallocation_fn_p (elt)
                    && FUNCTION_ARG_CHAIN (elt) == void_list_node)
                  goto ok;
@@ -7062,9 +7056,8 @@ build_op_delete_call (enum tree_code code, tree addr, tree size,
        allocation function. If the lookup finds a single matching
        deallocation function, that function will be called; otherwise, no
        deallocation function will be called."  */
-    for (lkp_iterator iter (MAYBE_BASELINK_FUNCTIONS (fns)); iter; ++iter)
+    for (tree elt : lkp_range (MAYBE_BASELINK_FUNCTIONS (fns)))
       {
-       tree elt = *iter;
        dealloc_info di_elt;
        if (usual_deallocation_fn_p (elt, &di_elt))
          {
@@ -9669,10 +9662,8 @@ has_trivial_copy_assign_p (tree type, bool access, bool *hasassign)
   /* Iterate over overloads of the assignment operator, checking
      accessible copy assignments for triviality.  */
 
-  for (ovl_iterator oi (fns); oi; ++oi)
+  for (tree f : ovl_range (fns))
     {
-      tree f = *oi;
-
       /* Skip operators that aren't copy assignments.  */
       if (!copy_fn_p (f))
        continue;
@@ -9715,10 +9706,8 @@ has_trivial_copy_p (tree type, bool access, bool hasctor[2])
   tree fns = get_class_binding (type, complete_ctor_identifier);
   bool all_trivial = true;
 
-  for (ovl_iterator oi (fns); oi; ++oi)
+  for (tree f : ovl_range (fns))
     {
-      tree f = *oi;
-
       /* Skip template constructors.  */
       if (TREE_CODE (f) != FUNCTION_DECL)
        continue;

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index dad3849d44fe9bb9a887b2c7348d281167b4e121..66bc1eea682258e25f3413241ffb84cee35ffb4c 100644 (file)
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -1347,10 +1347,10 @@ handle_using_decl (tree using_decl, tree t)
 
   /* Make type T see field decl FDECL with access ACCESS.  */
   if (flist)
-    for (ovl_iterator iter (flist); iter; ++iter)
+    for (tree f : ovl_range (flist))
       {
-       add_method (t, *iter, true);
-       alter_access (t, *iter, access);
+       add_method (t, f, true);
+       alter_access (t, f, access);
       }
   else if (USING_DECL_UNRELATED_P (using_decl))
     {
@@ -2259,18 +2259,20 @@ maybe_warn_about_overly_private_class (tree t)
       if (!TYPE_HAS_COPY_CTOR (t))
        nonprivate_ctor = true;
       else
-       for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t));
-            !nonprivate_ctor && iter; ++iter)
-         if (TREE_PRIVATE (*iter))
+       for (tree fn : ovl_range (CLASSTYPE_CONSTRUCTORS (t)))
+         if (TREE_PRIVATE (fn))
            continue;
-         else if (copy_fn_p (*iter) || move_fn_p (*iter))
+         else if (copy_fn_p (fn) || move_fn_p (fn))
            /* Ideally, we wouldn't count any constructor that takes
               an argument of the class type as a parameter, because
               such things cannot be used to construct an instance of
               the class unless you already have one.  */
-           copy_or_move = *iter;
+           copy_or_move = fn;
          else
-           nonprivate_ctor = true;
+           {
+             nonprivate_ctor = true;
+             break;
+           }
 
       if (!nonprivate_ctor)
        {
@@ -2876,10 +2878,8 @@ get_basefndecls (tree name, tree t, vec<tree> *base_fndecls)
   bool found_decls = false;
 
   /* Find virtual functions in T with the indicated NAME.  */
-  for (ovl_iterator iter (get_class_binding (t, name)); iter; ++iter)
+  for (tree method : ovl_range (get_class_binding (t, name)))
     {
-      tree method = *iter;
-
       if (TREE_CODE (method) == FUNCTION_DECL && DECL_VINDEX (method))
        {
          base_fndecls->safe_push (method);
@@ -2988,9 +2988,8 @@ warn_hidden (tree t)
          continue;
 
        /* Remove any overridden functions.  */
-       for (ovl_iterator iter (fns); iter; ++iter)
+       for (tree fndecl : ovl_range (fns))
          {
-           tree fndecl = *iter;
            if (TREE_CODE (fndecl) == FUNCTION_DECL
                && DECL_VINDEX (fndecl))
              {
@@ -3334,8 +3333,8 @@ add_implicitly_declared_members (tree t, tree* access_decls,
          tree ctor_list = decl;
          location_t loc = input_location;
          input_location = DECL_SOURCE_LOCATION (using_decl);
-         for (ovl_iterator iter (ctor_list); iter; ++iter)
-           one_inherited_ctor (*iter, t, using_decl);
+         for (tree fn : ovl_range (ctor_list))
+           one_inherited_ctor (fn, t, using_decl);
          *access_decls = TREE_CHAIN (*access_decls);
          input_location = loc;
        }
@@ -4751,9 +4750,8 @@ check_methods (tree t)
        TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = true;
     }
 
-  for (ovl_iterator i (CLASSTYPE_CONSTRUCTORS (t)); i; ++i)
+  for (tree fn : ovl_range (CLASSTYPE_CONSTRUCTORS (t)))
     {
-      tree fn = *i;
       if (!user_provided_p (fn))
        /* Might be trivial.  */;
       else if (copy_fn_p (fn))
@@ -4762,10 +4760,8 @@ check_methods (tree t)
        TYPE_HAS_COMPLEX_MOVE_CTOR (t) = true;
     }
 
-  for (ovl_iterator i (get_class_binding_direct (t, assign_op_identifier));
-       i; ++i)
+  for (tree fn : ovl_range (get_class_binding_direct (t, assign_op_identifier)))
     {
-      tree fn = *i;
       if (!user_provided_p (fn))
        /* Might be trivial.  */;
       else if (copy_fn_p (fn))
@@ -5107,8 +5103,8 @@ clone_constructors_and_destructors (tree t)
 {
   /* We do not need to propagate the usingness to the clone, at this
      point that is not needed.  */
-  for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
-    clone_cdtor (*iter, /*update_methods=*/true);
+  for (tree fn : ovl_range (CLASSTYPE_CONSTRUCTORS (t)))
+    clone_cdtor (fn, /*update_methods=*/true);
 
   if (tree dtor = CLASSTYPE_DESTRUCTOR (t))
     clone_cdtor (dtor, /*update_methods=*/true);
@@ -5283,9 +5279,8 @@ type_has_user_nondefault_constructor (tree t)
   if (!TYPE_HAS_USER_CONSTRUCTOR (t))
     return false;
 
-  for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
+  for (tree fn : ovl_range (CLASSTYPE_CONSTRUCTORS (t)))
     {
-      tree fn = *iter;
       if (user_provided_p (fn)
          && (TREE_CODE (fn) == TEMPLATE_DECL
              || (skip_artificial_parms_for (fn, DECL_ARGUMENTS (fn))

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 368d9f5adf79acddb8a03e7c8dd815c3a8c38373..a08867aea628cad0d8dcf2f0a954f646f2144032 100644 (file)
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -817,11 +817,6 @@ class ovl_iterator {
   {
   }
 
- private:
-  /* Do not duplicate.  */
-  ovl_iterator &operator= (const ovl_iterator &);
-  ovl_iterator (const ovl_iterator &);
-
  public:
   operator bool () const
   {
@@ -841,6 +836,10 @@ class ovl_iterator {
 
     return fn;
   }
+  bool operator== (const ovl_iterator &o) const
+  {
+    return ovl == o.ovl;
+  }
   tree get_using () const
   {
     gcc_checking_assert (using_p ());
@@ -903,6 +902,19 @@ class ovl_iterator {
   static tree reveal_node (tree ovl, tree node);
 };
 
+/* Treat a tree as a range of ovl_iterator, e.g.
+   for (tree f : ovl_range (fns)) { ... }  */
+
+class ovl_range
+{
+  tree t;
+  bool allow;
+public:
+  explicit ovl_range (tree t, bool allow = false): t(t), allow(allow) { }
+  ovl_iterator begin() { return ovl_iterator (t, allow); }
+  ovl_iterator end() { return ovl_iterator (NULL_TREE, allow); }
+};
+
 /* Iterator over a (potentially) 2 dimensional overload, which is
    produced by name lookup.  */
 
@@ -935,6 +947,18 @@ class lkp_iterator : public ovl_iterator {
   }
 };
 
+/* Treat a tree as a range of lkp_iterator, e.g.
+   for (tree f : lkp_range (fns)) { ... }  */
+
+class lkp_range
+{
+  tree t;
+public:
+  lkp_range (tree t): t(t) { }
+  lkp_iterator begin() { return lkp_iterator (t); }
+  lkp_iterator end() { return lkp_iterator (NULL_TREE); }
+};
+
 /* hash traits for declarations.  Hashes potential overload sets via
    DECL_NAME.  */