[gcc r13-8075] Fix internal error on function returning dynamically-sized type

[Eric Botcazou <ebotcazou@gcc.gnu.org>]

https://gcc.gnu.org/g:c5e1cb7e501350ea339db44ca5a33704d817a6fb

commit r13-8075-gc5e1cb7e501350ea339db44ca5a33704d817a6fb
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Thu Nov 16 18:36:44 2023 +0100

    Fix internal error on function returning dynamically-sized type
    
    This is a tree sharing issue for the internal return type synthesized for
    a function returning a dynamically-sized type and taking an Out or In/Out
    parameter passed by copy.
    
    gcc/ada/
            * gcc-interface/decl.cc (gnat_to_gnu_subprog_type): Also create a
            TYPE_DECL for the return type built for the CI/CO mechanism.
    
    gcc/testsuite/
            * gnat.dg/varsize4.ads, gnat.dg/varsize4.adb: New test.
            * gnat.dg/varsize4_pkg.ads: New helper.

Diff:
---
 gcc/ada/gcc-interface/decl.cc          |  6 ++++++
 gcc/testsuite/gnat.dg/varsize4.adb     | 19 +++++++++++++++++++
 gcc/testsuite/gnat.dg/varsize4.ads     |  9 +++++++++
 gcc/testsuite/gnat.dg/varsize4_pkg.ads |  5 +++++
 4 files changed, 39 insertions(+)

diff --git a/gcc/ada/gcc-interface/decl.cc b/gcc/ada/gcc-interface/decl.cc
index 00cb3a6cf3b..1c5dd646186 100644
--- a/gcc/ada/gcc-interface/decl.cc
+++ b/gcc/ada/gcc-interface/decl.cc
@@ -6285,6 +6285,12 @@ gnat_to_gnu_subprog_type (Entity_Id gnat_subprog, bool definition,
 
 	  if (debug_info_p)
 	    rest_of_record_type_compilation (gnu_cico_return_type);
+
+	  /* Declare it now since it will never be declared otherwise.  This
+	     is necessary to ensure that its subtrees are properly marked.  */
+	  create_type_decl (TYPE_NAME (gnu_cico_return_type),
+			    gnu_cico_return_type,
+			    true, debug_info_p, gnat_subprog);
 	}
 
       gnu_return_type = gnu_cico_return_type;
diff --git a/gcc/testsuite/gnat.dg/varsize4.adb b/gcc/testsuite/gnat.dg/varsize4.adb
new file mode 100644
index 00000000000..3d0430de5aa
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/varsize4.adb
@@ -0,0 +1,19 @@
+-- { dg-do compile }
+
+package body Varsize4 is
+
+   function Func (bytes_read : out Natural) return Arr is
+      Ret : Arr := (others => False);
+   begin
+      return Ret;
+   end;
+
+   function Get return Natural is
+      Data  : Arr;
+      Bytes : Natural;
+   begin
+      Data := Func (Bytes);
+      return Bytes;
+   end;
+
+end Varsize4;
diff --git a/gcc/testsuite/gnat.dg/varsize4.ads b/gcc/testsuite/gnat.dg/varsize4.ads
new file mode 100644
index 00000000000..62b673fc16b
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/varsize4.ads
@@ -0,0 +1,9 @@
+with Varsize4_Pkg;
+
+package Varsize4 is
+
+   type Arr is array (1 .. Varsize4_Pkg.F) of Boolean;
+
+   function Get return Natural;
+
+end Varsize4;
diff --git a/gcc/testsuite/gnat.dg/varsize4_pkg.ads b/gcc/testsuite/gnat.dg/varsize4_pkg.ads
new file mode 100644
index 00000000000..e07a6b002dc
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/varsize4_pkg.ads
@@ -0,0 +1,5 @@
+package Varsize4_Pkg is
+
+   function F return Natural;
+
+end Varsize4_Pkg;