[gcc r13-667] [Ada] Do not give warnings for compiler-generated entities by default

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:e4c84b82c5f903de6911157281a837481bca780e

commit r13-667-ge4c84b82c5f903de6911157281a837481bca780e
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Wed Mar 23 14:46:28 2022 +0100

    [Ada] Do not give warnings for compiler-generated entities by default
    
    The rationale is that these entities are almost always the result of
    expansion activities in the front-end, over which the user has very
    limited control.  These warnings can be restored by means of -gnatD.
    
    gcc/ada/
    
            * gcc-interface/utils.cc (gnat_pushdecl): Also set TREE_NO_WARNING
            on the decl if Comes_From_Source is false for the associated node.

Diff:
---
 gcc/ada/gcc-interface/utils.cc | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/gcc/ada/gcc-interface/utils.cc b/gcc/ada/gcc-interface/utils.cc
index d747c639a8f..c583acaf967 100644
--- a/gcc/ada/gcc-interface/utils.cc
+++ b/gcc/ada/gcc-interface/utils.cc
@@ -852,8 +852,11 @@ gnat_pushdecl (tree decl, Node_Id gnat_node)
   if (!deferred_decl_context)
     DECL_CONTEXT (decl) = context;
 
-  suppress_warning (decl, all_warnings,
-		    No (gnat_node) || Warnings_Off (gnat_node));
+  /* Disable warnings for compiler-generated entities or explicit request.  */
+  if (No (gnat_node)
+      || !Comes_From_Source (gnat_node)
+      || Warnings_Off (gnat_node))
+    suppress_warning (decl);
 
   /* Set the location of DECL and emit a declaration for it.  */
   if (Present (gnat_node) && !renaming_from_instantiation_p (gnat_node))