[gcc r12-5097] [Ada] Avoid warnings regarding rep clauses in generics

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

https://gcc.gnu.org/g:db778c7022cc0e5b2b4100ccc7c2e52a0eaba3c0

commit r12-5097-gdb778c7022cc0e5b2b4100ccc7c2e52a0eaba3c0
Author: Bob Duff <duff@adacore.com>
Date:   Wed Nov 3 12:06:28 2021 -0400

    [Ada] Avoid warnings regarding rep clauses in generics
    
    gcc/ada/
    
            * repinfo.adb (List_Common_Type_Info, List_Object_Info): Add
            check for In_Generic_Scope.
            (List_Component_Layout): Check for known static values.
            * sem_ch13.adb (Check_Record_Representation_Clause): Add check
            for In_Generic_Scope.

Diff:
---
 gcc/ada/repinfo.adb  | 29 ++++++++++++++++++++++-------
 gcc/ada/sem_ch13.adb |  6 ++++--
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/gcc/ada/repinfo.adb b/gcc/ada/repinfo.adb
index b86885cec6c..a11057a1a49 100644
--- a/gcc/ada/repinfo.adb
+++ b/gcc/ada/repinfo.adb
@@ -38,6 +38,7 @@ with Output;         use Output;
 with Osint.C;        use Osint.C;
 with Sem_Aux;        use Sem_Aux;
 with Sem_Eval;       use Sem_Eval;
+with Sem_Util;
 with Sinfo;          use Sinfo;
 with Sinfo.Nodes;    use Sinfo.Nodes;
 with Sinfo.Utils;    use Sinfo.Utils;
@@ -426,11 +427,14 @@ package body Repinfo is
          end if;
 
       --  Alignment is not always set for task, protected, and class-wide
-      --  types.
+      --  types. Representation aspects are not computed for types in a
+      --  generic unit.
 
       else
          pragma Assert
-           (Is_Concurrent_Type (Ent) or else Is_Class_Wide_Type (Ent));
+           (Is_Concurrent_Type (Ent) or else
+              Is_Class_Wide_Type (Ent) or else
+              Sem_Util.In_Generic_Scope (Ent));
       end if;
    end List_Common_Type_Info;
 
@@ -902,6 +906,13 @@ package body Repinfo is
 
    procedure List_Object_Info (Ent : Entity_Id) is
    begin
+      --  The information has not been computed in a generic unit, so don't try
+      --  to print it.
+
+      if Sem_Util.In_Generic_Scope (Ent) then
+         return;
+      end if;
+
       Write_Separator;
 
       if List_Representation_Info_To_JSON then
@@ -1176,13 +1187,17 @@ package body Repinfo is
             Write_Str (" range  ");
          end if;
 
-         Sbit := Starting_First_Bit + Fbit;
+         if Known_Static_Normalized_First_Bit (Ent) then
+            Sbit := Starting_First_Bit + Fbit;
 
-         if Sbit >= SSU then
-            Sbit := Sbit - SSU;
-         end if;
+            if Sbit >= SSU then
+               Sbit := Sbit - SSU;
+            end if;
 
-         UI_Write (Sbit, Decimal);
+            UI_Write (Sbit, Decimal);
+         else
+            Write_Unknown_Val;
+         end if;
 
          if List_Representation_Info_To_JSON then
             Write_Line (", ");
diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb
index f6679456f2b..d63d60fb385 100644
--- a/gcc/ada/sem_ch13.adb
+++ b/gcc/ada/sem_ch13.adb
@@ -12618,9 +12618,11 @@ package body Sem_Ch13 is
       end if;
 
       --  Skip the following warnings if overlap was detected; programmer
-      --  should fix the errors first.
+      --  should fix the errors first. Also skip the warnings for types in
+      --  generics, because their representation information is not fully
+      --  computed.
 
-      if not Overlap_Detected then
+      if not Overlap_Detected and then not In_Generic_Scope (Rectype) then
          --  Check for record holes (gaps)
 
          if Warn_On_Record_Holes then