From 78b3bf0e65072f5fa42a8da43698711220d4f8ef Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Thu, 16 Mar 2023 15:35:15 -0400
Subject: [PATCH] c++: __func__ and local class DMI [PR105809]

As in 108242, we need to instantiate in the context of the enclosing
function, not after it's gone.

	PR c++/105809

gcc/cp/ChangeLog:

	* init.cc (get_nsdmi): Split out...
	(maybe_instantiate_nsdmi_init): ...this function.
	* cp-tree.h: Declare it.
	* pt.cc (tsubst_expr): Use it.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/constexpr-__func__3.C: New test.
---
 gcc/cp/cp-tree.h                                 |  1 +
 gcc/cp/init.cc                                   | 27 ++++++++++++++++--------
 gcc/cp/pt.cc                                     |  6 ++++++
 gcc/testsuite/g++.dg/cpp0x/constexpr-__func__3.C | 15 +++++++++++++
 4 files changed, 40 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-__func__3.C

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index dfc1c84..b74c18b 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7086,6 +7086,7 @@ extern bool is_copy_initialization		(tree);
 extern tree build_zero_init			(tree, tree, bool);
 extern tree build_value_init			(tree, tsubst_flags_t);
 extern tree build_value_init_noctor		(tree, tsubst_flags_t);
+extern tree maybe_instantiate_nsdmi_init	(tree, tsubst_flags_t);
 extern tree get_nsdmi				(tree, bool, tsubst_flags_t);
 extern tree build_offset_ref			(tree, tree, bool,
 						 tsubst_flags_t);
diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index 1b7d3d8..9030237 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -561,18 +561,16 @@ perform_target_ctor (tree init)
   return init;
 }
 
-/* Return the non-static data initializer for FIELD_DECL MEMBER.  */
+/* Instantiate the default member initializer of MEMBER, if needed.
+   Only get_nsdmi should use the return value of this function.  */
 
 static GTY((cache)) decl_tree_cache_map *nsdmi_inst;
 
 tree
-get_nsdmi (tree member, bool in_ctor, tsubst_flags_t complain)
+maybe_instantiate_nsdmi_init (tree member, tsubst_flags_t complain)
 {
-  tree init;
-  tree save_ccp = current_class_ptr;
-  tree save_ccr = current_class_ref;
-  
-  if (DECL_LANG_SPECIFIC (member) && DECL_TEMPLATE_INFO (member))
+  tree init = DECL_INITIAL (member);
+  if (init && DECL_LANG_SPECIFIC (member) && DECL_TEMPLATE_INFO (member))
     {
       init = DECL_INITIAL (DECL_TI_TEMPLATE (member));
       location_t expr_loc
@@ -642,8 +640,19 @@ get_nsdmi (tree member, bool in_ctor, tsubst_flags_t complain)
 	  input_location = sloc;
 	}
     }
-  else
-    init = DECL_INITIAL (member);
+
+  return init;
+}
+
+/* Return the non-static data initializer for FIELD_DECL MEMBER.  */
+
+tree
+get_nsdmi (tree member, bool in_ctor, tsubst_flags_t complain)
+{
+  tree save_ccp = current_class_ptr;
+  tree save_ccr = current_class_ref;
+
+  tree init = maybe_instantiate_nsdmi_init (member, complain);
 
   if (init && TREE_CODE (init) == DEFERRED_PARSE)
     {
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 1072882..056b8c7 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -19353,6 +19353,8 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 	  /* Closures are handled by the LAMBDA_EXPR.  */
 	  gcc_assert (!LAMBDA_TYPE_P (TREE_TYPE (t)));
 	  complete_type (tmp);
+	  tree save_ccp = current_class_ptr;
+	  tree save_ccr = current_class_ref;
 	  for (tree fld = TYPE_FIELDS (tmp); fld; fld = DECL_CHAIN (fld))
 	    if ((VAR_P (fld)
 		 || (TREE_CODE (fld) == FUNCTION_DECL
@@ -19360,6 +19362,10 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 		&& DECL_TEMPLATE_INSTANTIATION (fld))
 	      instantiate_decl (fld, /*defer_ok=*/false,
 				/*expl_inst_class=*/false);
+	    else if (TREE_CODE (fld) == FIELD_DECL)
+	      maybe_instantiate_nsdmi_init (fld, tf_warning_or_error);
+	  current_class_ptr = save_ccp;
+	  current_class_ref = save_ccr;
 	}
       break;
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__3.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__3.C
new file mode 100644
index 0000000..365a4e0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__3.C
@@ -0,0 +1,15 @@
+// PR c++/105809
+// { dg-do compile { target c++11 } }
+
+template<typename ss> void hh() {  ss t; }
+
+template<int>
+int f(void)
+{
+    constexpr char const* cc = __func__;
+    struct j{  char const* kk=cc; };
+    hh<j>();
+    return 0;
+}
+
+int t = f<1>();
-- 
2.7.4