Re: [C++] Avoid producing duplicate binfos for member pointers

[Jason Merrill <jason at redhat dot com>]

On 06/30/2014 11:58 AM, Jason Merrill wrote:
> On 06/30/2014 08:42 AM, Jason Merrill wrote:
> > Hmm, I wonder why we need BINFOs at all for the ptrmemfunc RECORD_TYPEs,
> > which are not classes.
>
> I'm working on removing both BINFO and TYPE_LANG_SPECIFIC.

Like so.  Applying to trunk.

commit 8988eb91d4be24fb630f4d8538110a5f83d44daa
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Jun 30 08:34:33 2014 -0400

    	* decl.c (build_ptrmemfunc_type): Don't give a PMF RECORD_TYPE
    	TYPE_BINFO or TYPE_LANG_SPECIFIC.
    	* cp-tree.h (TYPE_PTRMEMFUNC_FLAG): Use TYPE_LANG_FLAG_2.
    	(TYPE_PTRMEMFUNC_P): Don't expect TYPE_LANG_SPECIFIC.
    	* typeck.c (build_ptrmemfunc_access_expr): Don't use lookup_member.
    	* pt.c (unify): Also check whether the argument is a PMF.

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index c1bd7cf..1e9e1af 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -126,6 +126,7 @@ c-common.h, not after.
    0: TYPE_DEPENDENT_P
    1: TYPE_HAS_USER_CONSTRUCTOR.
    2: TYPE_HAS_LATE_RETURN_TYPE (in FUNCTION_TYPE, METHOD_TYPE)
+      TYPE_PTRMEMFUNC_FLAG (in RECORD_TYPE)
    3: TYPE_FOR_JAVA.
    4: TYPE_HAS_NONTRIVIAL_DESTRUCTOR
    5: CLASS_TYPE_P (in RECORD_TYPE and UNION_TYPE)
@@ -3561,11 +3562,10 @@ more_aggr_init_expr_args_p (const aggr_init_expr_arg_iterator *iter)
    function type.  */
 #define TYPE_PTRMEMFUNC_P(NODE)		\
   (TREE_CODE (NODE) == RECORD_TYPE	\
-   && TYPE_LANG_SPECIFIC (NODE)		\
    && TYPE_PTRMEMFUNC_FLAG (NODE))
 
 #define TYPE_PTRMEMFUNC_FLAG(NODE) \
-  (LANG_TYPE_CLASS_CHECK (NODE)->ptrmemfunc_flag)
+  (TYPE_LANG_FLAG_2 (RECORD_TYPE_CHECK (NODE)))
 
 /* Returns true if NODE is a pointer-to-member.  */
 #define TYPE_PTRMEM_P(NODE) \
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 6902bb0..909f762 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -8073,13 +8073,10 @@ build_ptrmemfunc_type (tree type)
     unqualified_variant
       = build_ptrmemfunc_type (TYPE_MAIN_VARIANT (type));
 
-  t = make_class_type (RECORD_TYPE);
-  xref_basetypes (t, NULL_TREE);
+  t = make_node (RECORD_TYPE);
 
-  /* Let the front end know this is a pointer to member function...  */
+  /* Let the front end know this is a pointer to member function.  */
   TYPE_PTRMEMFUNC_FLAG (t) = 1;
-  /* ... and not really a class type.  */
-  SET_CLASS_TYPE_P (t, 0);
 
   field = build_decl (input_location, FIELD_DECL, pfn_identifier, type);
   fields = field;
@@ -8109,7 +8106,6 @@ build_ptrmemfunc_type (tree type)
       TYPE_MAIN_VARIANT (t) = unqualified_variant;
       TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (unqualified_variant);
       TYPE_NEXT_VARIANT (unqualified_variant) = t;
-      TREE_TYPE (TYPE_BINFO (t)) = t;
     }
 
   /* Cache this pointer-to-member type so that we can find it again
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 7f33b6d..70a946c 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18104,6 +18104,8 @@ unify (tree tparms, tree targs, tree parm, tree arg, int strict,
 			TYPE_PTRMEMFUNC_FN_TYPE (arg),
 			strict, explain_p);
 	}
+      else if (TYPE_PTRMEMFUNC_P (arg))
+	return unify_type_mismatch (explain_p, parm, arg);
 
       if (CLASSTYPE_TEMPLATE_INFO (parm))
 	{
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 042e600..9758dfe 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -2848,8 +2848,10 @@ build_ptrmemfunc_access_expr (tree ptrmem, tree member_name)
      type.  */
   ptrmem_type = TREE_TYPE (ptrmem);
   gcc_assert (TYPE_PTRMEMFUNC_P (ptrmem_type));
-  member = lookup_member (ptrmem_type, member_name, /*protect=*/0,
-			  /*want_type=*/false, tf_warning_or_error);
+  for (member = TYPE_FIELDS (ptrmem_type); member;
+       member = DECL_CHAIN (member))
+    if (DECL_NAME (member) == member_name)
+      break;
   return build_simple_component_ref (ptrmem, member);
 }