From 31f7f784fe7fa68bca218df43ec8965569d6cb5d Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 1 Nov 2016 21:50:29 -0400
Subject: Implement P0136R1, Rewording inheriting constructors.

gcc/c-family/
	* c.opt (-fnew-inheriting-ctors): New.
	* c-opts.c: Default to on for ABI 11+.
gcc/cp/
	* call.c (enum rejection_reason_code): Add rr_inherited_ctor.
	(inherited_ctor_rejection): New.
	(add_function_candidate): Reject inherited ctors for copying.
	(enforce_access): Use strip_inheriting_ctors.
	(print_z_candidate): Likewise.  Handle rr_inherited_ctor.
	(convert_like_real): Avoid copying inheriting ctor parameters.
	(build_over_call): Likewise.  A base ctor inheriting from vbase
	has no parms.  Sorry about varargs.
	(joust): A local constructor beats inherited with the same convs.
	* class.c (add_method): Handle hiding inheriting ctors.
	(one_inherited_ctor): Handle new semantics.
	(add_implicitly_declared_members): Pass using_decl down.
	(build_clone): A base ctor inheriting from vbase has no parms.
	* cp-tree.h (DECL_INHERITED_CTOR): Store this instead of the base.
	(SET_DECL_INHERITED_CTOR): Likewise.
	(DECL_INHERITED_CTOR_BASE): Adjust.
	* constexpr.c: Adjust.
	* error.c (dump_function_decl): Decorate inheriting ctors.
	* init.c (emit_mem_initializers): Suppress access control in
	inheriting ctor.
	* mangle.c (write_special_name_constructor): Handle new inheriting
	ctor mangling.
	* method.c (strip_inheriting_ctors, inherited_ctor_binfo)
	(ctor_omit_inherited_parms, binfo_inherited_from): New.
	(synthesized_method_walk): Use binfo_inherited_from.  Suppress
	access control in inheriting ctor.
	(deduce_inheriting_ctor): Deleted if ambiguous ctor inheritance.
	(maybe_explain_implicit_delete): Explain ambigous ctor inheritance.
	(add_one_base_init, do_build_copy_constructor): Adjust.
	(locate_fn_flags, explain_implicit_non_constexpr): Adjust.
	(implicitly_declare_fn): Adjust.
	(get_inherited_ctor): Remove.
	* name-lookup.c (do_class_using_decl): Check for indirect ctor
	inheritance.
	* optimize.c (cdtor_comdat_group): Adjust for new mangling.
	(maybe_clone_body): Handle omitted parms in base clone.
	(maybe_thunk_body): Don't thunk if base clone omits parms.
	* pt.c (tsubst_decl): Adjust.
	(instantiate_template_1): Suppress access control in inheriting
	ctor.
	(fn_type_unification): Do deduction with inherited ctor.
	* tree.c (special_function_p): Adjust.
gcc/
	* tree-inline.c (copy_tree_body_r): Only copy the taken branch of
	a COND_EXPR with constant condition.
libiberty/
	* cp-demangle.c (d_ctor_dtor_name): Handle inheriting constructor.

From-SVN: r241765
---
 gcc/cp/optimize.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'gcc/cp/optimize.c')

diff --git a/gcc/cp/optimize.c b/gcc/cp/optimize.c
index e2032c1..b926ef7 100644
--- a/gcc/cp/optimize.c
+++ b/gcc/cp/optimize.c
@@ -166,7 +166,8 @@ cdtor_comdat_group (tree complete, tree base)
       {
 	gcc_assert (!diff_seen
 		    && idx > 0
-		    && (p[idx - 1] == 'C' || p[idx - 1] == 'D')
+		    && (p[idx - 1] == 'C' || p[idx - 1] == 'D'
+			|| p[idx - 1] == 'I')
 		    && p[idx] == '1'
 		    && q[idx] == '2');
 	grp_name[idx] = '5';
@@ -259,6 +260,11 @@ maybe_thunk_body (tree fn, bool force)
      (for non-vague linkage ctors) or the COMDAT group (otherwise).  */
 
   populate_clone_array (fn, fns);
+
+  /* Don't use thunks if the base clone omits inherited parameters.  */
+  if (ctor_omit_inherited_parms (fns[0]))
+    return 0;
+
   DECL_ABSTRACT_P (fn) = false;
   if (!DECL_WEAK (fn))
     {
@@ -490,7 +496,7 @@ maybe_clone_body (tree fn)
 	parm = DECL_CHAIN (parm);
       if (DECL_HAS_VTT_PARM_P (clone))
 	clone_parm = DECL_CHAIN (clone_parm);
-      for (; parm;
+      for (; parm && clone_parm;
 	   parm = DECL_CHAIN (parm), clone_parm = DECL_CHAIN (clone_parm))
 	/* Update this parameter.  */
 	update_cloned_parm (parm, clone_parm, first);
@@ -616,7 +622,8 @@ maybe_clone_body (tree fn)
               else
                 {
                   decl_map->put (parm, clone_parm);
-                  clone_parm = DECL_CHAIN (clone_parm);
+		  if (clone_parm)
+		    clone_parm = DECL_CHAIN (clone_parm);
                 }
             }
 
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