Implement C++11 delegating constructors.

* cp-tree.h (enum cpp0x_warn_str): Add CPP0X_DELEGATING_CTORS.
	* error.c (maybe_warn_cpp0x): Adjust.
	* parser.c (cp_parser_mem_initializer_list): Use it.  Diagnose
	multiple initializers if a delegating initializer is present.
	* call.c (build_special_member_call): Convert an assert into an if.
	* init.c (perform_target_ctor): New.
	(emit_mem_initializers): Use it.
	(expand_member_init, expand_default_init): Adjust.

Co-Authored-By: Pedro Lamarão <pedro.lamarao@gmail.com>

From-SVN: r182012

gcc/cp/ChangeLog

@@ -1,3 +1,16 @@
+2011-12-05  Ville Voutilainen  <ville.voutilainen@gmail.com>
+	    Pedro Lamarão  <pedro.lamarao@gmail.com>
+
+	Implement C++11 delegating constructors.
+	* cp-tree.h (enum cpp0x_warn_str): Add CPP0X_DELEGATING_CTORS.
+	* error.c (maybe_warn_cpp0x): Adjust.
+	* parser.c (cp_parser_mem_initializer_list): Use it.  Diagnose
+	multiple initializers if a delegating initializer is present.
+	* call.c (build_special_member_call): Convert an assert into an if.
+	* init.c (perform_target_ctor): New.
+	(emit_mem_initializers): Use it.
+	(expand_member_init, expand_default_init): Adjust.
+
 2011-12-05  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/51404

gcc/cp/call.c

@@ -6978,8 +6978,10 @@ build_special_member_call (tree instance, tree name, VEC(tree,gc) **args,
 			    current_in_charge_parm, integer_zero_node),
 		    current_vtt_parm,
 		    vtt);
-      gcc_assert (BINFO_SUBVTT_INDEX (binfo));
-      sub_vtt = fold_build_pointer_plus (vtt, BINFO_SUBVTT_INDEX (binfo));
+      if (BINFO_SUBVTT_INDEX (binfo))
+	sub_vtt = fold_build_pointer_plus (vtt, BINFO_SUBVTT_INDEX (binfo));
+      else
+	sub_vtt = vtt;
 
       if (args == NULL)
 	{

gcc/cp/cp-tree.h

@@ -404,7 +404,9 @@ typedef enum cpp0x_warn_str
   /* non-static data member initializers */
   CPP0X_NSDMI,
   /* user defined literals */
-  CPP0X_USER_DEFINED_LITERALS
+  CPP0X_USER_DEFINED_LITERALS,
+  /* delegating constructors */
+  CPP0X_DELEGATING_CTORS
 } cpp0x_warn_str;
   
 /* The various kinds of operation used by composite_pointer_type. */

gcc/cp/error.c

@@ -3304,6 +3304,11 @@ maybe_warn_cpp0x (cpp0x_warn_str str)
 		 "user-defined literals "
 		 "only available with -std=c++11 or -std=gnu++11");
 	break;
+      case CPP0X_DELEGATING_CTORS:
+	pedwarn (input_location, 0,
+		 "delegating constructors "
+		 "only available with -std=c++11 or -std=gnu++11");
+        break;
       default:
 	gcc_unreachable ();
       }

gcc/cp/init.c

@@ -485,6 +485,30 @@ build_value_init_noctor (tree type, tsubst_flags_t complain)
   return build_zero_init (type, NULL_TREE, /*static_storage_p=*/false);
 }
 
+/* Initialize current class with INIT, a TREE_LIST of
+   arguments for a target constructor. If TREE_LIST is void_type_node,
+   an empty initializer list was given.  */
+
+static void
+perform_target_ctor (tree init)
+{
+  tree decl = current_class_ref;
+  tree type = current_class_type;
+
+  finish_expr_stmt (build_aggr_init (decl, init, LOOKUP_NORMAL,
+                                     tf_warning_or_error));
+  if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
+    {
+      tree expr = build_delete (type, decl, sfk_complete_destructor,
+				LOOKUP_NORMAL
+				|LOOKUP_NONVIRTUAL
+				|LOOKUP_DESTRUCTOR,
+				0, tf_warning_or_error);
+      if (expr != error_mark_node)
+	finish_eh_cleanup (expr);
+    }
+}
+
 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
    arguments.  If TREE_LIST is void_type_node, an empty initializer
    list was given; if NULL_TREE no initializer was given.  */
@@ -988,6 +1012,16 @@ emit_mem_initializers (tree mem_inits)
   if (!COMPLETE_TYPE_P (current_class_type))
     return;
 
+  if (mem_inits
+      && TYPE_P (TREE_PURPOSE (mem_inits))
+      && same_type_p (TREE_PURPOSE (mem_inits), current_class_type))
+    {
+      /* Delegating constructor. */
+      gcc_assert (TREE_CHAIN (mem_inits) == NULL_TREE);
+      perform_target_ctor (TREE_VALUE (mem_inits));
+      return;
+    }
+
   if (DECL_DEFAULTED_FN (current_function_decl))
     flags |= LOOKUP_DEFAULTED;
 
@@ -1318,8 +1352,9 @@ expand_member_init (tree name)
       tree virtual_binfo;
       int i;
 
-      if (current_template_parms)
-	return basetype;
+      if (same_type_p (basetype, current_class_type)
+	  || current_template_parms)
+	  return basetype;
 
       class_binfo = TYPE_BINFO (current_class_type);
       direct_binfo = NULL_TREE;
@@ -1578,13 +1613,33 @@ expand_default_init (tree binfo, tree true_exp, tree exp, tree init, int flags,
   else
     parms = make_tree_vector_single (init);
 
-  if (true_exp == exp)
-    ctor_name = complete_ctor_identifier;
-  else
-    ctor_name = base_ctor_identifier;
-
-  rval = build_special_member_call (exp, ctor_name, &parms, binfo, flags,
-                                    complain);
+  if (exp == current_class_ref && current_function_decl
+      && DECL_HAS_IN_CHARGE_PARM_P (current_function_decl))
+    {
+      /* Delegating constructor. */
+      tree complete;
+      tree base;
+      complete = build_special_member_call (exp, complete_ctor_identifier,
+					&parms, binfo, flags,
+					complain);
+      base = build_special_member_call (exp, base_ctor_identifier,
+					&parms, binfo, flags,
+					complain);
+      rval = build3 (COND_EXPR, TREE_TYPE (complete),
+		    build2 (EQ_EXPR, boolean_type_node,
+			    current_in_charge_parm, integer_zero_node),
+		    base,
+		    complete);
+    }
+   else
+    {
+      if (true_exp == exp)
+	ctor_name = complete_ctor_identifier;
+      else
+	ctor_name = base_ctor_identifier;
+      rval = build_special_member_call (exp, ctor_name, &parms, binfo, flags,
+					complain);
+  }
 
   if (parms != NULL)
     release_tree_vector (parms);

gcc/cp/parser.c

@@ -11321,6 +11321,7 @@ static void
 cp_parser_mem_initializer_list (cp_parser* parser)
 {
   tree mem_initializer_list = NULL_TREE;
+  tree target_ctor = error_mark_node;
   cp_token *token = cp_lexer_peek_token (parser->lexer);
 
   /* Let the semantic analysis code know that we are starting the
@@ -11358,6 +11359,27 @@ cp_parser_mem_initializer_list (cp_parser* parser)
           if (mem_initializer != error_mark_node)
             mem_initializer = make_pack_expansion (mem_initializer);
         }
+      if (target_ctor != error_mark_node
+	  && mem_initializer != error_mark_node)
+	{
+	  error ("mem-initializer for %qD follows constructor delegation",
+		 TREE_PURPOSE (mem_initializer));
+	  mem_initializer = error_mark_node;
+	}
+      /* Look for a target constructor. */
+      if (mem_initializer != error_mark_node
+	  && TYPE_P (TREE_PURPOSE (mem_initializer))
+	  && same_type_p (TREE_PURPOSE (mem_initializer), current_class_type))
+	{
+	  maybe_warn_cpp0x (CPP0X_DELEGATING_CTORS);
+	  if (mem_initializer_list)
+	    {
+	      error ("constructor delegation follows mem-initializer for %qD",
+		     TREE_PURPOSE (mem_initializer_list));
+	      mem_initializer = error_mark_node;
+	    }
+	  target_ctor = mem_initializer;
+	}
       /* Add it to the list, unless it was erroneous.  */
       if (mem_initializer != error_mark_node)
 	{

gcc/testsuite/ChangeLog

@@ -1,3 +1,13 @@
+2011-12-05  Ville Voutilainen  <ville.voutilainen@gmail.com>
+	    Pedro Lamarão <pedro.lamarao@gmail.com>
+
+	* g++.dg/cpp0x/dc1.C: New test.
+	* g++.dg/cpp0x/dc2.C: New test.
+	* g++.dg/cpp0x/dc3.C: New test.
+	* g++.dg/cpp0x/dc4.C: New test.
+	* g++.dg/cpp0x/dc5.C: New test.
+	* g++.dg/template/meminit1.C: Adjust expected error.
+
 2011-12-05  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/51404

gcc/testsuite/g++.dg/cpp0x/dc1.C

@@ -0,0 +1,43 @@
+// { dg-do compile }
+// { dg-options --std=c++0x }
+
+struct B {
+	int i;
+	B (int _i) : i(_i) { }
+	~B () { i = 0; }
+};
+
+struct A : public B {
+	A () : B(-1) { }
+	A (int i) : A() { }
+	A (double b) : A(static_cast<int>(b)) { }
+	A (double b, double b2) : A(b2) { }
+	~A () { }
+};
+
+void f_A () { A a(2.0, 3.0); }
+
+struct C {
+	C () { }
+	virtual ~C() { }
+	virtual int f () = 0;
+};
+
+struct D : public C {
+	int i;
+	D (int _i) : C(), i(_i) { }
+	D () : D(-1) { }
+	virtual ~D() { }
+	virtual int f () { }
+};
+
+void f_D () { C* c = new D(); }
+
+template <typename T>
+struct E {
+	T t;
+	E () : E(T()) { }
+	E (T _t) : t(_t) { }
+};
+
+void f_E () { E<int> e; }

gcc/testsuite/g++.dg/cpp0x/dc2.C

@@ -0,0 +1,23 @@
+// { dg-do compile }
+// { dg-options --std=c++0x }
+
+struct A {
+	int i, j;
+	A () : A(0), j(0) { } // { dg-error "constructor delegation" }
+	A (int _i) : i(_i) { }
+};
+
+struct B {
+	int i, j;
+	B () : i(0), B(0) { } // { dg-error "constructor delegation" }
+	B (int _j) : j(_j) { }
+
+};
+
+struct C {};
+
+struct D : public C {
+	D () : C() { }
+	D (float) : D(), C() { } // { dg-error "constructor delegation" }
+	D (float, float): C(), D() { } // { dg-error "constructor delegation" }
+};

gcc/testsuite/g++.dg/cpp0x/dc3.C

@@ -0,0 +1,63 @@
+// { dg-do compile }
+// { dg-options --std=c++0x }
+
+struct X {};
+
+struct B {
+	int i;
+	B (int _i) : i(_i) { }
+	~B () { i = 0; }
+};
+
+template <typename T>
+struct A : public B {
+	A () : B(-1) { }
+	~A () { }
+};
+
+template <typename T>
+struct A<T*> : public B {
+	A () : B(-1) { }
+	A (int i) : A() { }
+	A (double b) : A(static_cast<int>(b)) { }
+	A (double b, double b2) : A(b2) { }
+	~A () { }
+};
+
+void f_A () { A<X*> a(2.0, 3.0); }
+
+struct C {
+	C () { }
+	virtual ~C() { }
+	virtual int f () = 0;
+};
+
+template <typename T>
+struct D : public C {
+	int i;
+	D (int _i) : C(), i(_i) { }
+};
+
+template <>
+struct D<X> : public C {
+	int i;
+	D (int _i) : C(), i(_i) { }
+	D () : D(-1) { }
+	virtual ~D() { }
+	virtual int f () { }
+};
+
+void f_D () { D<X>* d = new D<X>(); }
+
+template <typename T>
+struct E {
+};
+
+template <>
+struct E<int> {
+	int i;
+	E () : E(0) { }
+	E (int _i) : i(_i) { }
+};
+
+void f_E () { E<int> e; }

gcc/testsuite/g++.dg/cpp0x/dc4.C

@@ -0,0 +1,7 @@
+// { dg-do compile }
+// { dg-options "--std=c++98" }
+
+struct X {
+  X() {}
+  X(int) : X() {} // { dg-warning "delegating constructors" }
+};

gcc/testsuite/g++.dg/cpp0x/dc5.C

@@ -0,0 +1,28 @@
+// { dg-do run }
+// { dg-options "--std=c++0x" }
+
+#include <cassert>
+
+int count = 0;
+struct VB
+{
+  VB() {++count;}
+};
+
+struct B : virtual VB
+{
+  B() : B(42) {}
+  B(int)  {}
+};
+
+struct D : B
+{
+  D() {}
+  D(int) : D() {}
+};
+
+int main()
+{
+  D d{42};
+  assert(count == 1);
+}

gcc/testsuite/g++.dg/template/meminit1.C

@@ -2,7 +2,7 @@
 template <class T >
 struct S
 {
-  S() : S() {} // { dg-error "base" }
+  S() : S() {} // { dg-message "delegating constructors" }
 };
 
-S<int> s; // { dg-message "required" }
+S<int> s;