Revert empty class parameter passing ABI changes.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@234977 138bc75d-0d04-0410-961f-82ee72b054a4

63 files changed, 49 insertions, 1010 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ca2a9a74600..e56d15bc40d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2016-04-14  Jason Merrill  <jason@redhat.com>
+
+	* cfgexpand.c, expr.c: Revert previous change.
+
 2016-04-14  Cesar Philippidis  <cesar@codesourcery.com>
 
 	PR middle-end/70643
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 4a5cf166869..1341c14ce2b 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -73,7 +73,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "builtins.h"
 #include "tree-chkp.h"
 #include "rtl-chkp.h"
-#include "langhooks.h"
 
 /* Some systems use __main in a way incompatible with its use in gcc, in these
    cases use the macros NAME__MAIN to give a quoted symbol and SYMBOL__MAIN to
@@ -6222,15 +6221,6 @@ pass_expand::execute (function *fun)
 		 (int) PARAM_VALUE (PARAM_SSP_BUFFER_SIZE));
     }
 
-  if (warn_abi)
-    if (tree attr = lookup_attribute ("abi warning",
-				      DECL_ATTRIBUTES (current_function_decl)))
-      warning_at (DECL_SOURCE_LOCATION (current_function_decl),
-		  OPT_Wabi, "definition of %qs: %s",
-		  identifier_to_locale (lang_hooks.decl_printable_name
-					(current_function_decl, 1)),
-		  TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr))));
-
   /* Set up parameters and prepare for return, for the function.  */
   expand_function_start (current_function_decl);
 
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 866b4f2dbba..4267f65daaa 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2016-04-14  Jason Merrill  <jason@redhat.com>
+
+	* call.c, decl.c, error.c, cp-tree.h, decl.c: Revert empty
+	parameter ABI change.
+
 2016-04-13  Martin Sebor  <msebor@redhat.com>
 
 	PR c++/69517
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 687e7bd4dce..ed234904a63 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -214,8 +214,6 @@ static void add_candidates (tree, tree, const vec<tree, va_gc> *, tree, tree,
 			    tsubst_flags_t);
 static conversion *merge_conversion_sequences (conversion *, conversion *);
 static tree build_temp (tree, tree, int, diagnostic_t *, tsubst_flags_t);
-static bool pass_as_empty_struct (tree type);
-static tree empty_class_arg (tree);
 
 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
    NAME can take many forms...  */
@@ -381,31 +379,16 @@ build_call_a (tree function, int n, tree *argarray)
   /* Don't pass empty class objects by value.  This is useful
      for tags in STL, which are used to control overload resolution.
      We don't need to handle other cases of copying empty classes.  */
-  bool warned = false;
-  if (decl && !TREE_PUBLIC (decl))
-    /* Don't warn about the ABI of a function local to this TU.  */
-    warned = true;
-  tree empty_arg = NULL_TREE;
   if (! decl || ! DECL_BUILT_IN (decl))
     for (i = 0; i < n; i++)
       {
 	tree arg = CALL_EXPR_ARG (function, i);
-	tree type = TREE_TYPE (arg);
-	if (is_really_empty_class (type)
-	    && ! TREE_ADDRESSABLE (type))
+	if (is_empty_class (TREE_TYPE (arg))
+	    && ! TREE_ADDRESSABLE (TREE_TYPE (arg)))
 	  {
-	    empty_arg = arg;
-	    CALL_EXPR_ARG (function, i) = empty_class_arg (arg);
-	  }
-	/* Warn about ABI changes for a non-final argument.  */
-	else if (!warned && empty_arg)
-	  {
-	    location_t loc = EXPR_LOC_OR_LOC (empty_arg, input_location);
-	    if (decl && !varargs_function_p (decl))
-	      mark_for_abi_warning (decl, empty_arg);
-	    else
-	      warn_empty_class_abi (empty_arg, loc);
-	    warned = true;
+	    tree t = build0 (EMPTY_CLASS_EXPR, TREE_TYPE (arg));
+	    arg = build2 (COMPOUND_EXPR, TREE_TYPE (t), arg, t);
+	    CALL_EXPR_ARG (function, i) = arg;
 	  }
       }
 
@@ -6889,15 +6872,6 @@ build_x_va_arg (source_location loc, tree expr, tree type)
       expr = build_va_arg (loc, expr, ref);
       return convert_from_reference (expr);
     }
-  else if (is_really_empty_class (type) && !TREE_ADDRESSABLE (type))
-    {
-      /* Do the reverse of empty_class_arg.  */
-      tree etype = pass_as_empty_struct (type) ? empty_struct_type : type;
-      expr = build_va_arg (loc, expr, etype);
-      warn_empty_class_abi (type, loc);
-      tree ec = build0 (EMPTY_CLASS_EXPR, type);
-      return build2 (COMPOUND_EXPR, type, expr, ec);
-    }
 
   return build_va_arg (loc, expr, type);
 }
@@ -6994,75 +6968,6 @@ convert_default_arg (tree type, tree arg, tree fn, int parmnum,
   return arg;
 }
 
-/* Return true iff TYPE should be passed and returned as a size 0 type rather
-   than its normal size, for compatibility with C.  */
-
-static bool
-pass_as_empty_struct (tree type)
-{
-  return (abi_version_at_least (10)
-	  && type != error_mark_node
-	  && COMPLETE_TYPE_P (type)
-	  && !TREE_ADDRESSABLE (type)
-	  && is_really_empty_class (type));
-}
-
-/* Adjust the value VAL of empty class type TYPE for argument passing.
-   Keep this synced with build_x_va_arg.  */
-
-static tree
-empty_class_arg (tree val)
-{
-  /* Don't pass empty class objects by value.  This is useful
-     for tags in STL, which are used to control overload resolution.
-     We don't need to handle other cases of copying empty classes.  */
-  tree type = TREE_TYPE (val);
-  tree etype = pass_as_empty_struct (type) ? empty_struct_type : type;
-  tree empty = build0 (EMPTY_CLASS_EXPR, etype);
-  return build2 (COMPOUND_EXPR, etype, val, empty);
-}
-
-/* Generate a message warning about the change in empty class parameter passing
-   ABI.  */
-
-static tree
-empty_class_msg (tree type)
-{
-  if (!TYPE_P (type))
-    type = TREE_TYPE (type);
-
-  return pp_format_to_string ("empty class %qT parameter passing ABI "
-			      "changes in -fabi-version=10 (GCC 6)", type);
-}
-
-/* Warn immediately about the change in empty class parameter ABI.  */
-
-void
-warn_empty_class_abi (tree arg, location_t loc)
-{
-  if (!warn_abi || !abi_version_crosses (10))
-    return;
-
-  warning_at (loc, OPT_Wabi, "%E", empty_class_msg (arg));
-}
-
-/* Tack a warning about the change in empty class parameter ABI onto FN, so
-   that we get a warning if a definition or call is emitted.  */
-
-void
-mark_for_abi_warning (tree fn, tree type)
-{
-  if (!warn_abi || !abi_version_crosses (10))
-    return;
-  if (lookup_attribute ("abi warning", DECL_ATTRIBUTES (fn)))
-    return;
-
-  tree msg = empty_class_msg (type);
-  msg = build_tree_list (NULL_TREE, msg);
-  DECL_ATTRIBUTES (fn) = tree_cons (get_identifier ("abi warning"), msg,
-				    DECL_ATTRIBUTES (fn));
-}
-
 /* Returns the type which will really be used for passing an argument of
    type TYPE.  */
 
@@ -7081,8 +6986,6 @@ type_passed_as (tree type)
 	   && COMPLETE_TYPE_P (type)
 	   && tree_int_cst_lt (TYPE_SIZE (type), TYPE_SIZE (integer_type_node)))
     type = integer_type_node;
-  else if (pass_as_empty_struct (type))
-    type = empty_struct_type;
 
   return type;
 }
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 87e3ea0b2ee..baff674dfb7 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -1150,8 +1150,6 @@ enum cp_tree_index
     CPTI_NULLPTR,
     CPTI_NULLPTR_TYPE,
 
-    CPTI_EMPTY_STRUCT,
-
     CPTI_MAX
 };
 
@@ -1187,7 +1185,6 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
 #define current_aggr			cp_global_trees[CPTI_AGGR_TAG]
 #define nullptr_node			cp_global_trees[CPTI_NULLPTR]
 #define nullptr_type_node		cp_global_trees[CPTI_NULLPTR_TYPE]
-#define empty_struct_type		cp_global_trees[CPTI_EMPTY_STRUCT]
 
 /* We cache these tree nodes so as to call get_identifier less
    frequently.  */
@@ -5540,8 +5537,6 @@ extern tree build_addr_func			(tree, tsubst_flags_t);
 extern void set_flags_from_callee		(tree);
 extern tree build_call_a			(tree, int, tree*);
 extern tree build_call_n			(tree, int, ...);
-extern void mark_for_abi_warning		(tree, tree);
-extern void warn_empty_class_abi		(tree, location_t);
 extern bool null_ptr_cst_p			(tree);
 extern bool null_member_pointer_value_p		(tree);
 extern bool sufficient_parms_p			(const_tree);
@@ -5896,7 +5891,6 @@ extern bool pedwarn_cxx98                       (location_t, int, const char *,
 extern location_t location_of                   (tree);
 extern void qualified_name_lookup_error		(tree, tree, tree,
 						 location_t);
-extern tree pp_format_to_string			(const char *, ...);
 
 /* in except.c */
 extern void init_exception_processing		(void);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 42e853f2190..65b5733b020 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -4180,10 +4180,6 @@ cxx_init_decl_processing (void)
     nullptr_node = build_int_cst (nullptr_type_node, 0);
   }
 
-  empty_struct_type = make_node (RECORD_TYPE);
-  finish_builtin_struct (empty_struct_type, "__empty_struct",
-			 NULL_TREE, NULL_TREE);
-
   abort_fndecl
     = build_library_fn_ptr ("__cxa_pure_virtual", void_ftype,
 			    ECF_NORETURN | ECF_NOTHROW);
@@ -14375,34 +14371,16 @@ store_parm_decls (tree current_function_parms)
 	     they end in the correct forward order.  */
       specparms = nreverse (specparms);
 
-      /* Don't warn about the ABI of a function local to this TU.  */
-      bool warned = !TREE_PUBLIC (current_function_decl);
-      bool saw_nonempty = false;
       for (parm = specparms; parm; parm = next)
 	{
 	  next = DECL_CHAIN (parm);
 	  if (TREE_CODE (parm) == PARM_DECL)
 	    {
-	      tree type = TREE_TYPE (parm);
 	      if (DECL_NAME (parm) == NULL_TREE
-		  || !VOID_TYPE_P (type))
+		  || !VOID_TYPE_P (parm))
 		pushdecl (parm);
 	      else
 		error ("parameter %qD declared void", parm);
-	      /* If this isn't the last parameter, maybe warn about ABI change
-		 in passing empty classes.  */
-	      if (processing_template_decl)
-		continue;
-	      if (TREE_ADDRESSABLE (type)
-		  || !is_really_empty_class (type))
-		saw_nonempty = true;
-	      else if (!warned
-		       && (saw_nonempty
-			   || varargs_function_p (current_function_decl)))
-		{
-		  mark_for_abi_warning (current_function_decl, type);
-		  warned = true;
-		}
 	    }
 	  else
 	    {
diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index 5aaa1773bca..aa5fd411b28 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -3718,25 +3718,3 @@ qualified_name_lookup_error (tree scope, tree name,
       suggest_alternatives_for (location, name);
     }
 }
-
-/* Like error et al, but return the formatted message as a STRING_CST.  */
-
-tree
-pp_format_to_string (const char *msg, ...)
-{
-  pretty_printer *pp = global_dc->printer;
-  text_info text;
-  va_list ap;
-
-  va_start (ap, msg);
-  text.err_no = errno;
-  text.args_ptr = &ap;
-  text.format_spec = msg;
-  pp_format (pp, &text);
-  pp_output_formatted_text (pp);
-  va_end (ap);
-  const char *fmt = pp_formatted_text (pp);
-  tree str = build_string (strlen (fmt) + 1, fmt);
-  pp_clear_output_area (pp);
-  return str;
-}
diff --git a/gcc/expr.c b/gcc/expr.c
index 5f1118c4f7b..29d22b07256 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -10579,13 +10579,6 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 		      0, "%Kcall to %qs declared with attribute warning: %s",
 		      exp, identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 1)),
 		      TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr))));
-	if (warn_abi && fndecl
-	    && (attr = lookup_attribute ("abi warning",
-					 DECL_ATTRIBUTES (fndecl))) != NULL)
-	  warning_at (tree_nonartificial_location (exp),
-		      OPT_Wabi, "%Kcall to %qs: %s",
-		      exp, identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 1)),
-		      TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr))));
 
 	/* Check for a built-in function.  */
 	if (fndecl && DECL_BUILT_IN (fndecl))
diff --git a/gcc/testsuite/g++.dg/abi/empty12.C b/gcc/testsuite/g++.dg/abi/empty12.C
deleted file mode 100644
index ce1f6f2ae9c..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty12.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty12a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty12.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f); // { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty12.h b/gcc/testsuite/g++.dg/abi/empty12.h
deleted file mode 100644
index c61afcda0fb..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty12.h
+++ /dev/null
@@ -1,9 +0,0 @@
-struct dummy { };
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty12a.c b/gcc/testsuite/g++.dg/abi/empty12a.c
deleted file mode 100644
index 34a25bad75d..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty12a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty12.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty13.C b/gcc/testsuite/g++.dg/abi/empty13.C
deleted file mode 100644
index d1e094685de..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty13.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-x c -fabi-version=9" }
-// { dg-additional-sources "empty13a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty13.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f);
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty13.h b/gcc/testsuite/g++.dg/abi/empty13.h
deleted file mode 100644
index c61afcda0fb..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty13.h
+++ /dev/null
@@ -1,9 +0,0 @@
-struct dummy { };
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty13a.c b/gcc/testsuite/g++.dg/abi/empty13a.c
deleted file mode 100644
index b4303a63826..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty13a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty13.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 == -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty14.C b/gcc/testsuite/g++.dg/abi/empty14.C
deleted file mode 100644
index 1b9c3975753..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty14.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty14a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty14.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f); // { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty14.h b/gcc/testsuite/g++.dg/abi/empty14.h
deleted file mode 100644
index 5842279cf37..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty14.h
+++ /dev/null
@@ -1,10 +0,0 @@
-struct dummy0 { };
-struct dummy { struct dummy0 d[140]; };
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty14a.c b/gcc/testsuite/g++.dg/abi/empty14a.c
deleted file mode 100644
index 8b3d7800c36..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty14a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty14.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty15.C b/gcc/testsuite/g++.dg/abi/empty15.C
deleted file mode 100644
index ac0a8681dc9..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty15.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty15a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty15.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f); // { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty15.h b/gcc/testsuite/g++.dg/abi/empty15.h
deleted file mode 100644
index 1c6f26f5ae8..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty15.h
+++ /dev/null
@@ -1,30 +0,0 @@
-struct A1 {};
-struct A2 {};
-struct B1 { struct A1 a; struct A2 b; };
-struct B2 { struct A1 a; struct A2 b; };
-struct C1 { struct B1 a; struct B2 b; };
-struct C2 { struct B1 a; struct B2 b; };
-struct D1 { struct C1 a; struct C2 b; };
-struct D2 { struct C1 a; struct C2 b; };
-struct E1 { struct D1 a; struct D2 b; };
-struct E2 { struct D1 a; struct D2 b; };
-struct F1 { struct E1 a; struct E2 b; };
-struct F2 { struct E1 a; struct E2 b; };
-struct G1 { struct F1 a; struct F2 b; };
-struct G2 { struct F1 a; struct F2 b; };
-struct H1 { struct G1 a; struct G2 b; };
-struct H2 { struct G1 a; struct G2 b; };
-struct I1 { struct H1 a; struct H2 b; };
-struct I2 { struct H1 a; struct H2 b; };
-struct J1 { struct I1 a; struct I2 b; };
-struct J2 { struct I1 a; struct I2 b; };
-struct dummy { struct J1 a; struct J2 b; };
-
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty15a.c b/gcc/testsuite/g++.dg/abi/empty15a.c
deleted file mode 100644
index 325b2c5ba09..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty15a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty15.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty16.C b/gcc/testsuite/g++.dg/abi/empty16.C
deleted file mode 100644
index de2bf5cd51d..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty16.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty16a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty16.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f); // { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty16.h b/gcc/testsuite/g++.dg/abi/empty16.h
deleted file mode 100644
index 7552ae06576..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty16.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#ifdef __cplusplus
-struct A1 {};
-struct A2 {};
-struct dummy : A1, A2 {} ;
-#else
-struct dummy {};
-#endif
-
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty16a.c b/gcc/testsuite/g++.dg/abi/empty16a.c
deleted file mode 100644
index 6cb7fbccecc..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty16a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty16.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty17.C b/gcc/testsuite/g++.dg/abi/empty17.C
deleted file mode 100644
index c7a37c093d9..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty17.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty17a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty17.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f); // { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty17.h b/gcc/testsuite/g++.dg/abi/empty17.h
deleted file mode 100644
index 9cf72baca2e..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty17.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifdef __cplusplus
-struct A1
-{
-  void foo (void);
-  unsigned int : 15;
-};
-struct A2
-{
-  void bar (void);
-  unsigned int : 15;
-};
-struct dummy : A1, A2
-{
-  unsigned int : 15;
-};
-#else
-struct dummy {};
-#endif
-
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty17a.c b/gcc/testsuite/g++.dg/abi/empty17a.c
deleted file mode 100644
index 24408fde09c..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty17a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty17.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty18.C b/gcc/testsuite/g++.dg/abi/empty18.C
deleted file mode 100644
index 6cad33c8dd3..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty18.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty18a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty18.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f);			// { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty18.h b/gcc/testsuite/g++.dg/abi/empty18.h
deleted file mode 100644
index 86e7ecdd211..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty18.h
+++ /dev/null
@@ -1,9 +0,0 @@
-struct dummy { int d[0]; };
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty18a.c b/gcc/testsuite/g++.dg/abi/empty18a.c
deleted file mode 100644
index 902860bdc01..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty18a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty18.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty19.C b/gcc/testsuite/g++.dg/abi/empty19.C
deleted file mode 100644
index e3e855a99bb..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty19.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// PR c++/60336
-// { dg-do run }
-// { dg-options "-Wabi=9 -x c" }
-// { dg-additional-sources "empty19a.c" }
-// { dg-prune-output "command line option" }
-
-#include "empty19.h"
-extern "C" void fun(struct dummy, struct foo);
-
-int main()
-{
-  struct dummy d;
-  struct foo f = { -1, -2, -3, -4, -5 };
-
-  fun(d, f); // { dg-warning "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty19.h b/gcc/testsuite/g++.dg/abi/empty19.h
deleted file mode 100644
index 616b87bdd93..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty19.h
+++ /dev/null
@@ -1,10 +0,0 @@
-struct dummy0 { };
-struct dummy { struct dummy0 d[0]; };
-struct foo
-{
-  int i1;
-  int i2;
-  int i3;
-  int i4;
-  int i5;
-};
diff --git a/gcc/testsuite/g++.dg/abi/empty19a.c b/gcc/testsuite/g++.dg/abi/empty19a.c
deleted file mode 100644
index 767b1eb7320..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty19a.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "empty19.h"
-void fun(struct dummy d, struct foo f)
-{
-  if (f.i1 != -1)
-    __builtin_abort();
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty20.C b/gcc/testsuite/g++.dg/abi/empty20.C
deleted file mode 100644
index be1e826c838..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty20.C
+++ /dev/null
@@ -1,25 +0,0 @@
-// { dg-options "-Wabi=9 -O0" }
-
-struct A { };
-
-void f(A, A) { }		// No warning, trailing parms all empty
-void f(A, A, int) { }		// { dg-warning "ABI" }
-__attribute__ ((always_inline))
-inline void f(A a, int i) { }	// No warning, always inlined
-__attribute__ ((always_inline))
-inline void f2(A a, int i)	// But the call within the fn gets a warning
-{				// when it's inlined into main
-  f(a,a,i);			// { dg-warning "ABI" }
-}
-inline void f3(A a, int i)	// This one is never called
-{
-  f(a,a,i);
-}
-int main()
-{
-  A a;
-  f(a,a);
-  f(a,a,42);			// { dg-warning "ABI" }
-  f(a,42);
-  f2(a,42);
-}
diff --git a/gcc/testsuite/g++.dg/abi/empty21.C b/gcc/testsuite/g++.dg/abi/empty21.C
deleted file mode 100644
index 7538dd80c32..00000000000
--- a/gcc/testsuite/g++.dg/abi/empty21.C
+++ /dev/null
@@ -1,21 +0,0 @@
-// { dg-options "-Wabi=9" }
-
-#include <stdarg.h>
-
-struct A { };
-
-void f(int i, ...)
-{
-  va_list ap;
-  va_start (ap, i);
-  if (i >= 1)
-    va_arg (ap, A);		// { dg-warning "ABI" }
-  if (i >= 2)
-    va_arg (ap, int);
-}
-
-int main()
-{
-  f(0);
-  f(2, A(), 42);		// { dg-warning "ABI" }
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-1.C b/gcc/testsuite/g++.dg/abi/pr60336-1.C
deleted file mode 100644
index af0863887a0..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-1.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -std=c++11 -fno-pic" }
-// { dg-require-effective-target fpic }
-
-struct dummy { };
-struct true_type { struct dummy i; };
-
-extern true_type y;
-extern void xxx (true_type c);
-
-void
-yyy (void)
-{
-  xxx (y);
-}
-
-// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } }
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-10.C b/gcc/testsuite/g++.dg/abi/pr60336-10.C
deleted file mode 100644
index 6c9c990dad6..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-10.C
+++ /dev/null
@@ -1,50 +0,0 @@
-// { dg-do run }
-// { dg-options "-O2" }
-
-#include <stdarg.h>
-
-struct dummy0 { };
-struct dummy1 { };
-struct dummy : dummy0, dummy1 { };
-
-void
-test (struct dummy a, int m, ...)
-{
-  va_list va_arglist;
-  int i;
-  int count = 0;
-
-  if (m == 0)
-    count++;
-  va_start (va_arglist, m);
-  i = va_arg (va_arglist, int);
-  if (i == 1)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 2)
-  i = va_arg (va_arglist, int);
-    count++;
-  if (i == 3)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 4)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 5)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 6)
-    count++;
-  va_end (va_arglist);
-  if (count != 7)
-    __builtin_abort ();
-}
-
-struct dummy a0;
-
-int
-main ()
-{
-  test (a0, 0, 1, 2, 3, 4, 5, 6);
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-11.C b/gcc/testsuite/g++.dg/abi/pr60336-11.C
deleted file mode 100644
index c92f3d43a5b..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-11.C
+++ /dev/null
@@ -1,56 +0,0 @@
-// { dg-do run }
-// { dg-options "-O2" }
-
-#include <stdarg.h>
-
-struct dummy0
-{
-  void bar (void);
-};
-struct dummy1
-{
-  void foo (void);
-};
-struct dummy : dummy0, dummy1 { };
-
-void
-test (struct dummy a, int m, ...)
-{
-  va_list va_arglist;
-  int i;
-  int count = 0;
-
-  if (m == 0)
-    count++;
-  va_start (va_arglist, m);
-  i = va_arg (va_arglist, int);
-  if (i == 1)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 2)
-  i = va_arg (va_arglist, int);
-    count++;
-  if (i == 3)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 4)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 5)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 6)
-    count++;
-  va_end (va_arglist);
-  if (count != 7)
-    __builtin_abort ();
-}
-
-struct dummy a0;
-
-int
-main ()
-{
-  test (a0, 0, 1, 2, 3, 4, 5, 6);
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-12.C b/gcc/testsuite/g++.dg/abi/pr60336-12.C
deleted file mode 100644
index 83a7bb0cfa0..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-12.C
+++ /dev/null
@@ -1,57 +0,0 @@
-// { dg-do run }
-// { dg-options "-O2" }
-
-#include <stdarg.h>
-
-struct dummy0
-{
-};
-struct dummy1
-{
-  unsigned : 15;
-};
-struct dummy : dummy0, dummy1
-{
-};
-
-void
-test (struct dummy a, int m, ...)
-{
-  va_list va_arglist;
-  int i;
-  int count = 0;
-
-  if (m == 0)
-    count++;
-  va_start (va_arglist, m);
-  i = va_arg (va_arglist, int);
-  if (i == 1)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 2)
-  i = va_arg (va_arglist, int);
-    count++;
-  if (i == 3)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 4)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 5)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 6)
-    count++;
-  va_end (va_arglist);
-  if (count != 7)
-    __builtin_abort ();
-}
-
-struct dummy a0;
-
-int
-main ()
-{
-  test (a0, 0, 1, 2, 3, 4, 5, 6);
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-2.C b/gcc/testsuite/g++.dg/abi/pr60336-2.C
deleted file mode 100644
index 32eecb32a67..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-2.C
+++ /dev/null
@@ -1,48 +0,0 @@
-// { dg-do run }
-// { dg-options "-O2 -Wabi=9" }
-
-#include <stdarg.h>
-
-struct dummy { };
-
-void
-test (struct dummy a, int m, ...) // { dg-message "empty" }
-{
-  va_list va_arglist;
-  int i;
-  int count = 0;
-
-  if (m == 0)
-    count++;
-  va_start (va_arglist, m);
-  i = va_arg (va_arglist, int);
-  if (i == 1)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 2)
-  i = va_arg (va_arglist, int);
-    count++;
-  if (i == 3)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 4)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 5)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 6)
-    count++;
-  va_end (va_arglist);
-  if (count != 7)
-    __builtin_abort ();
-}
-
-struct dummy a0;
-
-int
-main ()
-{
-  test (a0, 0, 1, 2, 3, 4, 5, 6); // { dg-message "empty" }
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-3.C b/gcc/testsuite/g++.dg/abi/pr60336-3.C
deleted file mode 100644
index 8ebd4dda0e2..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-3.C
+++ /dev/null
@@ -1,15 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -Wabi=9" }
-
-struct dummy { struct{}__attribute__((aligned (4))) a[7]; };
-
-extern void test1 (struct dummy, ...);
-extern void (*test2) (struct dummy, ...);
-
-void
-foo ()
-{
-  struct dummy a0;
-  test1 (a0, 42); // { dg-message "empty" }
-  test2 (a0, 42); // { dg-message "empty" }
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-4.C b/gcc/testsuite/g++.dg/abi/pr60336-4.C
deleted file mode 100644
index 8790a663d2b..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-4.C
+++ /dev/null
@@ -1,48 +0,0 @@
-// { dg-do run { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } }
-// { dg-options "-O2 -fabi-version=9" }
-
-#include <stdarg.h>
-
-struct dummy { };
-
-void
-test (struct dummy a, int m, ...)
-{
-  va_list va_arglist;
-  int i;
-  int count = 0;
-
-  if (m == 0)
-    count++;
-  va_start (va_arglist, m);
-  i = va_arg (va_arglist, int);
-  if (i == 1)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 2)
-  i = va_arg (va_arglist, int);
-    count++;
-  if (i == 3)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 4)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 5)
-    count++;
-  i = va_arg (va_arglist, int);
-  if (i == 6)
-    count++;
-  va_end (va_arglist);
-  if (count == 7)
-    __builtin_abort ();
-}
-
-struct dummy a0;
-
-int
-main ()
-{
-  test (a0, 0, 1, 2, 3, 4, 5, 6);
-  return 0;
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-5.C b/gcc/testsuite/g++.dg/abi/pr60336-5.C
deleted file mode 100644
index b0c76ad5aa2..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-5.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -std=c++11 -fno-pic" }
-// { dg-require-effective-target fpic }
-
-struct dummy { };
-struct true_type { struct dummy i; struct dummy j; };
-
-extern true_type y;
-extern void xxx (true_type c);
-
-void
-yyy (void)
-{
-  xxx (y);
-}
-
-// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } }
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-6.C b/gcc/testsuite/g++.dg/abi/pr60336-6.C
deleted file mode 100644
index 58796519334..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-6.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -std=c++11 -fno-pic" }
-// { dg-require-effective-target fpic }
-
-struct dummy { };
-struct true_type { struct dummy i1; struct dummy i2; };
-
-extern true_type y;
-extern void xxx (true_type c);
-
-void
-yyy (void)
-{
-  xxx (y);
-}
-
-// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } }
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-7.C b/gcc/testsuite/g++.dg/abi/pr60336-7.C
deleted file mode 100644
index 0e5d2ef2f11..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-7.C
+++ /dev/null
@@ -1,17 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -std=c++11 -fno-pic" }
-// { dg-require-effective-target fpic }
-
-struct dummy { };
-struct true_type { struct dummy i[120]; };
-
-extern true_type y;
-extern void xxx (true_type c);
-
-void
-yyy (void)
-{
-  xxx (y);
-}
-
-// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } }
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-8.C b/gcc/testsuite/g++.dg/abi/pr60336-8.C
deleted file mode 100644
index fdfc924bfc5..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-8.C
+++ /dev/null
@@ -1,15 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -Wabi=9" }
-
-struct dummy { struct{} a[7][3]; };
-
-extern void test1 (struct dummy, ...);
-extern void (*test2) (struct dummy, ...);
-
-void
-foo ()
-{
-  struct dummy a0;
-  test1 (a0, 42); // { dg-message "empty" }
-  test2 (a0, 42); // { dg-message "empty" }
-}
diff --git a/gcc/testsuite/g++.dg/abi/pr60336-9.C b/gcc/testsuite/g++.dg/abi/pr60336-9.C
deleted file mode 100644
index 4ad333f6b9c..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr60336-9.C
+++ /dev/null
@@ -1,28 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -std=c++11 -fno-pic" }
-// { dg-require-effective-target fpic }
-
-struct A1 {}; struct A2 {};
-struct B1 { A1 a; A2 b; }; struct B2 { A1 a; A2 b; };
-struct C1 { B1 a; B2 b; }; struct C2 { B1 a; B2 b; };
-struct D1 { C1 a; C2 b; }; struct D2 { C1 a; C2 b; };
-struct E1 { D1 a; D2 b; }; struct E2 { D1 a; D2 b; };
-struct F1 { E1 a; E2 b; }; struct F2 { E1 a; E2 b; };
-struct G1 { F1 a; F2 b; }; struct G2 { F1 a; F2 b; };
-struct H1 { G1 a; G2 b; }; struct H2 { G1 a; G2 b; };
-struct I1 { H1 a; H2 b; }; struct I2 { H1 a; H2 b; };
-struct J1 { I1 a; I2 b; }; struct J2 { I1 a; I2 b; };
-struct dummy { J1 a; J2 b; };
-
-struct true_type { struct dummy i; };
-
-extern true_type y;
-extern void xxx (true_type c);
-
-void
-yyy (void)
-{
-  xxx (y);
-}
-
-// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } }
diff --git a/gcc/testsuite/g++.dg/abi/pr68355.C b/gcc/testsuite/g++.dg/abi/pr68355.C
deleted file mode 100644
index 1354fc497b5..00000000000
--- a/gcc/testsuite/g++.dg/abi/pr68355.C
+++ /dev/null
@@ -1,24 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O2 -std=c++11 -fno-pic" }
-// { dg-require-effective-target fpic }
-
-template<typename _Tp, _Tp __v>
-struct integral_constant
-{
-  static constexpr _Tp value = __v;
-  typedef _Tp value_type;
-  typedef integral_constant<_Tp, __v> type;
-  constexpr operator value_type() const { return value; }
-};
-
-typedef integral_constant<bool, true> true_type;
-extern void xxx (true_type c);
-
-void
-yyy (void)
-{
-  true_type y;
-  xxx (y);
-}
-
-// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx17integral_constantIbLb1EE" { target i?86-*-* x86_64-*-* } } }
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index d31a5d29120..f63e09145ba 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,7 @@
+2016-04-14  Jason Merrill  <jason@redhat.com>
+
+	Revert Jonathan's empty ABI change from yesterday.
+
 2016-04-13  Martin Sebor  <msebor@redhat.com>
 
 	PR c++/69517
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index bde003c68a0..57024e40ec0 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -84,32 +84,13 @@
 # define _GLIBCXX_DEPRECATED
 #endif
 
-#if __cplusplus
-
 // Macros for ABI tag attributes.
 #ifndef _GLIBCXX_ABI_TAG_CXX11
 # define _GLIBCXX_ABI_TAG_CXX11 __attribute ((__abi_tag__ ("cxx11")))
 #endif
 
-#if __GXX_ABI_VERSION >= 1010
-namespace std
-{
-  inline namespace _V2 { }
-}
-# define _GLIBCXX_BEGIN_NAMESPACE_EMPTY_TYPES \
-  _GLIBCXX_END_NAMESPACE_VERSION \
-  namespace _V2 { \
-  _GLIBCXX_BEGIN_NAMESPACE_VERSION
-# define _GLIBCXX_END_NAMESPACE_EMPTY_TYPES \
-  _GLIBCXX_END_NAMESPACE_VERSION \
-  } \
-  _GLIBCXX_BEGIN_NAMESPACE_VERSION
-# define _GLIBCXX_ABI_TAG_EMPTY __attribute ((__abi_tag__ ("cxxempty")))
-#else
-# define _GLIBCXX_BEGIN_NAMESPACE_EMPTY_TYPES
-# define _GLIBCXX_END_NAMESPACE_EMPTY_TYPES
-# define _GLIBCXX_ABI_TAG_EMPTY
-#endif
+
+#if __cplusplus
 
 // Macro for constexpr, to support in mixed 03/0x mode.
 #ifndef _GLIBCXX_CONSTEXPR
diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 22b71876129..5748920cc78 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -663,26 +663,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_insert_multi_node(__node_type* __hint,
 			   __hash_code __code, __node_type* __n);
 
-      template<bool _Uniq, typename... _Args>
-	typename enable_if<_Uniq, std::pair<iterator, bool>>::type
-	_M_emplace(__bool_constant<_Uniq>, _Args&&... __args);
+      template<typename... _Args>
+	std::pair<iterator, bool>
+	_M_emplace(std::true_type, _Args&&... __args);
 
-      template<bool _Uniq, typename... _Args>
-	typename enable_if<!_Uniq, iterator>::type
-	_M_emplace(__bool_constant<_Uniq> __uk, _Args&&... __args)
-	{
-	  return _M_emplace_hint(cend(), __uk, std::forward<_Args>(__args)...);
-	}
+      template<typename... _Args>
+	iterator
+	_M_emplace(std::false_type __uk, _Args&&... __args)
+	{ return _M_emplace(cend(), __uk, std::forward<_Args>(__args)...); }
 
       // Emplace with hint, useless when keys are unique.
       template<typename... _Args>
 	iterator
-	_M_emplace_hint(const_iterator, std::true_type __uk, _Args&&... __args)
+	_M_emplace(const_iterator, std::true_type __uk, _Args&&... __args)
 	{ return _M_emplace(__uk, std::forward<_Args>(__args)...).first; }
 
       template<typename... _Args>
 	iterator
-	_M_emplace_hint(const_iterator, std::false_type, _Args&&... __args);
+	_M_emplace(const_iterator, std::false_type, _Args&&... __args);
 
       template<typename _Arg, typename _NodeGenerator>
 	std::pair<iterator, bool>
@@ -714,10 +712,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		  const _NodeGenerator&, std::false_type);
 
       size_type
-      _M_erase(const key_type&, std::true_type);
+      _M_erase(std::true_type, const key_type&);
 
       size_type
-      _M_erase(const key_type&, std::false_type);
+      _M_erase(std::false_type, const key_type&);
 
       iterator
       _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n);
@@ -733,8 +731,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	iterator
 	emplace_hint(const_iterator __hint, _Args&&... __args)
 	{
-	  return _M_emplace_hint(__hint, __unique_keys(),
-				 std::forward<_Args>(__args)...);
+	  return _M_emplace(__hint, __unique_keys(),
+			    std::forward<_Args>(__args)...);
 	}
 
       // Insert member functions via inheritance.
@@ -750,7 +748,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       size_type
       erase(const key_type& __k)
-      { return _M_erase(__k, __unique_keys()); }
+      { return _M_erase(__unique_keys(), __k); }
 
       iterator
       erase(const_iterator, const_iterator);
@@ -1504,12 +1502,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   typename _Alloc, typename _ExtractKey, typename _Equal,
 	   typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
 	   typename _Traits>
-    template<bool _Uniq, typename... _Args>
+    template<typename... _Args>
       auto
       _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
 		 _H1, _H2, _Hash, _RehashPolicy, _Traits>::
-      _M_emplace(__bool_constant<_Uniq>, _Args&&... __args)
-      -> typename enable_if<_Uniq, pair<iterator, bool>>::type
+      _M_emplace(std::true_type, _Args&&... __args)
+      -> pair<iterator, bool>
       {
 	// First build the node to get access to the hash code
 	__node_type* __node = this->_M_allocate_node(std::forward<_Args>(__args)...);
@@ -1546,7 +1544,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       auto
       _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
 		 _H1, _H2, _Hash, _RehashPolicy, _Traits>::
-      _M_emplace_hint(const_iterator __hint, std::false_type, _Args&&... __args)
+      _M_emplace(const_iterator __hint, std::false_type, _Args&&... __args)
       -> iterator
       {
 	// First build the node to get its hash code.
@@ -1771,7 +1769,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     auto
     _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
 	       _H1, _H2, _Hash, _RehashPolicy, _Traits>::
-    _M_erase(const key_type& __k, std::true_type)
+    _M_erase(std::true_type, const key_type& __k)
     -> size_type
     {
       __hash_code __code = this->_M_hash_code(__k);
@@ -1795,7 +1793,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     auto
     _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
 	       _H1, _H2, _Hash, _RehashPolicy, _Traits>::
-    _M_erase(const key_type& __k, std::false_type)
+    _M_erase(std::false_type, const key_type& __k)
     -> size_type
     {
       __hash_code __code = this->_M_hash_code(__k);
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index ceb78b4d709..7a2ac92f839 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -906,8 +906,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	insert(const_iterator __hint, _Pair&& __v)
 	{
 	  __hashtable& __h = this->_M_conjure_hashtable();
-	  return __h._M_emplace_hint(__hint, __unique_keys(),
-				     std::forward<_Pair>(__v));
+	  return __h._M_emplace(__hint, __unique_keys(),
+				std::forward<_Pair>(__v));
 	}
    };
 
diff --git a/libstdc++-v3/include/bits/shared_ptr.h b/libstdc++-v3/include/bits/shared_ptr.h
index f4c27543c7b..b22477e96b2 100644
--- a/libstdc++-v3/include/bits/shared_ptr.h
+++ b/libstdc++-v3/include/bits/shared_ptr.h
@@ -166,7 +166,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *  __shared_ptr will release __p by calling __d(__p)
        */
       template<typename _Tp1, typename _Deleter, typename _Alloc>
-	_GLIBCXX_ABI_TAG_EMPTY
 	shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
 	: __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
 
@@ -186,7 +185,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *  The last owner will call __d(__p)
        */
       template<typename _Deleter, typename _Alloc>
-	_GLIBCXX_ABI_TAG_EMPTY
 	shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
 	: __shared_ptr<_Tp>(__p, __d, std::move(__a)) { }
 
diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h b/libstdc++-v3/include/bits/shared_ptr_base.h
index 6d523e17986..e844c9c91fe 100644
--- a/libstdc++-v3/include/bits/shared_ptr_base.h
+++ b/libstdc++-v3/include/bits/shared_ptr_base.h
@@ -436,7 +436,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	typedef _Sp_ebo_helper<1, _Alloc>	_Alloc_base;
 
       public:
-	_GLIBCXX_ABI_TAG_EMPTY
 	_Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
 	: _M_ptr(__p), _Del_base(__d), _Alloc_base(__a)
 	{ }
@@ -455,7 +454,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       : _M_impl(__p, __d, _Alloc()) { }
 
       // __d(__p) must not throw.
-      _GLIBCXX_ABI_TAG_EMPTY
       _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
       : _M_impl(__p, __d, __a) { }
 
@@ -586,7 +584,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	{ }
 
       template<typename _Ptr, typename _Deleter, typename _Alloc>
-	_GLIBCXX_ABI_TAG_EMPTY
 	__shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
 	{
 	  typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
@@ -903,7 +900,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	}
 
       template<typename _Tp1, typename _Deleter, typename _Alloc>
-	_GLIBCXX_ABI_TAG_EMPTY
 	__shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
 	: _M_ptr(__p), _M_refcount(__p, __d, std::move(__a))
 	{
@@ -918,7 +914,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	{ }
 
       template<typename _Deleter, typename _Alloc>
-	_GLIBCXX_ABI_TAG_EMPTY
         __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
 	: _M_ptr(0), _M_refcount(__p, __d, std::move(__a))
 	{ }
@@ -1044,7 +1039,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	{ __shared_ptr(__p, __d).swap(*this); }
 
       template<typename _Tp1, typename _Deleter, typename _Alloc>
-	_GLIBCXX_ABI_TAG_EMPTY
 	void
         reset(_Tp1* __p, _Deleter __d, _Alloc __a)
         { __shared_ptr(__p, __d, std::move(__a)).swap(*this); }
diff --git a/libstdc++-v3/include/bits/stl_algo.h b/libstdc++-v3/include/bits/stl_algo.h
index 28e1e3b2331..fbd03a79e1e 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -4270,7 +4270,6 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    *  is true then the assignment @c *i = @p __new_value is performed.
   */
   template<typename _ForwardIterator, typename _Predicate, typename _Tp>
-    _GLIBCXX_ABI_TAG_EMPTY
     void
     replace_if(_ForwardIterator __first, _ForwardIterator __last,
 	       _Predicate __pred, const _Tp& __new_value)
diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h
index e6ff00eec17..37ee5cc4053 100644
--- a/libstdc++-v3/include/bits/stl_pair.h
+++ b/libstdc++-v3/include/bits/stl_pair.h
@@ -72,17 +72,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
 
 #if __cplusplus >= 201103L
-
-_GLIBCXX_BEGIN_NAMESPACE_EMPTY_TYPES
-
   /// piecewise_construct_t
   struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
 
   /// piecewise_construct
   constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
 
-_GLIBCXX_END_NAMESPACE_EMPTY_TYPES
-
   // Forward declarations.
   template<typename...>
     class tuple;
diff --git a/libstdc++-v3/include/bits/uses_allocator.h b/libstdc++-v3/include/bits/uses_allocator.h
index 86162a8af8a..b1ff58a294b 100644
--- a/libstdc++-v3/include/bits/uses_allocator.h
+++ b/libstdc++-v3/include/bits/uses_allocator.h
@@ -42,15 +42,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     using __is_erased_or_convertible
       = __or_<is_same<_Tp, __erased_type>, is_convertible<_Alloc, _Tp>>;
 
-_GLIBCXX_BEGIN_NAMESPACE_EMPTY_TYPES
-
   /// [allocator.tag]
   struct allocator_arg_t { explicit allocator_arg_t() = default; };
 
   constexpr allocator_arg_t allocator_arg = allocator_arg_t();
 
-_GLIBCXX_END_NAMESPACE_EMPTY_TYPES
-
   template<typename _Tp, typename _Alloc, typename = __void_t<>>
     struct __uses_allocator_helper
     : false_type { };
@@ -69,15 +65,11 @@ _GLIBCXX_END_NAMESPACE_EMPTY_TYPES
 
   struct __uses_alloc_base { };
 
-_GLIBCXX_BEGIN_NAMESPACE_EMPTY_TYPES
-
   struct __uses_alloc0 : __uses_alloc_base
   {
     struct _Sink { void operator=(const void*) { } } _M_a;
   };
 
-_GLIBCXX_END_NAMESPACE_EMPTY_TYPES
-
   template<typename _Alloc>
     struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; };
 
diff --git a/libstdc++-v3/include/ext/pb_ds/assoc_container.hpp b/libstdc++-v3/include/ext/pb_ds/assoc_container.hpp
index a6b1e277a30..571d9468d7d 100644
--- a/libstdc++-v3/include/ext/pb_ds/assoc_container.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/assoc_container.hpp
@@ -120,44 +120,36 @@ namespace __gnu_pbds
       basic_hash_table(T0 t0) : base_type(t0) { }
 
     template<typename T0, typename T1>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1) : base_type(t0, t1) { }
 
     template<typename T0, typename T1, typename T2>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2) : base_type(t0, t1, t2) { }
 
     template<typename T0, typename T1, typename T2, typename T3>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2, T3 t3)
       : base_type(t0, t1, t2, t3) { }
 
     template<typename T0, typename T1, typename T2, typename T3, typename T4>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2, T3 t3, T4 t4)
       : base_type(t0, t1, t2, t3, t4) { }
 
     template<typename T0, typename T1, typename T2, typename T3, typename T4,
 	     typename T5>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2, T3 t3, T4 t4, T5 t5)
       : base_type(t0, t1, t2, t3, t4, t5) { }
 
     template<typename T0, typename T1, typename T2, typename T3, typename T4,
 	     typename T5, typename T6>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6)
       : base_type(t0, t1, t2, t3, t4, t5, t6) { }
 
     template<typename T0, typename T1, typename T2, typename T3, typename T4,
 	     typename T5, typename T6, typename T7>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7)
       : base_type(t0, t1, t2, t3, t4, t5, t6, t7) { }
 
     template<typename T0, typename T1, typename T2, typename T3, typename T4,
 	     typename T5, typename T6, typename T7, typename T8>
-      _GLIBCXX_ABI_TAG_EMPTY
       basic_hash_table(T0 t0, T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6,
 		       T7 t7, T8 t8)
       : base_type(t0, t1, t2, t3, t4, t5, t6, t7, t8)
diff --git a/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc b/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc
index 5487b0ac6a1..f3b2d87ab99 100644
--- a/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/scoped_allocator/69293_neg.cc
@@ -47,5 +47,5 @@ test01()
   scoped_alloc sa;
   auto p = sa.allocate(1);
   sa.construct(p);  // this is required to be ill-formed
-  // { dg-error "static assertion failed" "" { target *-*-* } 97 }
+  // { dg-error "static assertion failed" "" { target *-*-* } 89 }
 }
diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/cons/43820_neg.cc b/libstdc++-v3/testsuite/20_util/shared_ptr/cons/43820_neg.cc
index a0ce1f5a61b..395094f8bbe 100644
--- a/libstdc++-v3/testsuite/20_util/shared_ptr/cons/43820_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/shared_ptr/cons/43820_neg.cc
@@ -32,7 +32,7 @@ void test01()
 {
   X* px = 0;
   std::shared_ptr<X> p1(px);   // { dg-error "here" }
-  // { dg-error "incomplete" "" { target *-*-* } 892 }
+  // { dg-error "incomplete" "" { target *-*-* } 889 }
 
   std::shared_ptr<X> p9(ap());  // { dg-error "here" }
   // { dg-error "incomplete" "" { target *-*-* } 307 }
diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/cons/void_neg.cc b/libstdc++-v3/testsuite/20_util/shared_ptr/cons/void_neg.cc
index 88036fdcee9..8843ffea429 100644
--- a/libstdc++-v3/testsuite/20_util/shared_ptr/cons/void_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/shared_ptr/cons/void_neg.cc
@@ -25,5 +25,5 @@
 void test01()
 {
   std::shared_ptr<void> p((void*)nullptr);   // { dg-error "here" }
-  // { dg-error "incomplete" "" { target *-*-* } 891 }
+  // { dg-error "incomplete" "" { target *-*-* } 888 }
 }
diff --git a/libstdc++-v3/testsuite/20_util/uses_allocator/69293_neg.cc b/libstdc++-v3/testsuite/20_util/uses_allocator/69293_neg.cc
index 88e1ea10d84..19417fc2cef 100644
--- a/libstdc++-v3/testsuite/20_util/uses_allocator/69293_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/uses_allocator/69293_neg.cc
@@ -45,5 +45,5 @@ test01()
 {
   alloc_type a;
   std::tuple<X> t(std::allocator_arg, a); // this is required to be ill-formed
-  // { dg-error "static assertion failed" "" { target *-*-* } 97 }
+  // { dg-error "static assertion failed" "" { target *-*-* } 89 }
 }
diff --git a/libstdc++-v3/testsuite/20_util/uses_allocator/cons_neg.cc b/libstdc++-v3/testsuite/20_util/uses_allocator/cons_neg.cc
index e4cd2765bf7..b3df4ae9d7d 100644
--- a/libstdc++-v3/testsuite/20_util/uses_allocator/cons_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/uses_allocator/cons_neg.cc
@@ -44,4 +44,4 @@ void test01()
 
   tuple<Type> t(allocator_arg, a, 1);
 }
-// { dg-error "static assertion failed" "" { target *-*-* } 97 }
+// { dg-error "static assertion failed" "" { target *-*-* } 89 }
diff --git a/libstdc++-v3/testsuite/ext/profile/mutex_extensions_neg.cc b/libstdc++-v3/testsuite/ext/profile/mutex_extensions_neg.cc
index 8ffdee89f2a..e59d666307d 100644
--- a/libstdc++-v3/testsuite/ext/profile/mutex_extensions_neg.cc
+++ b/libstdc++-v3/testsuite/ext/profile/mutex_extensions_neg.cc
@@ -25,7 +25,7 @@
 
 #include <vector>
 
-// { dg-error "multiple inlined namespaces" "" { target *-*-* } 343 }
+// { dg-error "multiple inlined namespaces" "" { target *-*-* } 324 }
 
 // "template argument 1 is invalid"
 // { dg-prune-output "tuple:993" }