re PR ada/18434 (Ada: cannot build gnattools on Tru64 UNIX V5.1B)

2005-11-14  Robert Dewar  <dewar@adacore.com>
	    Ed Schonberg  <schonberg@adacore.com>

	PR ada/18434

	* types.ads: Include All_Checks in Suppress_Array

	* checks.adb (Check_Needed): Remove kludge for a/=b rewritten as
	not(a=b), since we no longer do this rewriting, and hence it is not
	needed.
	(Elaboration_Checks_Suppressed): Add special casing to
	deal with different cases of static and dynamic elaboration checks (all
	checks does not count in the first case, but does in the second).
	(Expr_Known_Valid): Do not assume that the result of any arbitrary
	function call is valid, since this is not the case.
	(Ensure_Valid): Do not apply validity check to a real literal
	in a universal or fixed context

	* exp_ch4.adb (Expand_N_Op_Ne): Don't expand a/=b to not(a=b) for
	elementary types using the operator in standard. It is cleaner not to
	modify the programmers intent, especially in the case of floating-point.
	(Rewrite_Comparison): Fix handling of /= (this was always wrong, but
	it did not matter because we always rewrote a/=b to not(a=b).
	(Expand_Allocator_Expression): For an allocator expression whose nominal
	subtype is an unconstrained packed type, convert the expression to its
	actual constrained subtype.
	Implement warning for <= or >= where < or > not possible
	Fix to Vax_Float tests (too early in many routines, causing premature
	Vax_Float expansions.

	* sem_prag.adb (Analyze_Pragma, case Obsolescent): Allow this pragma
	to be used with packages and generic packages as well as with
	subprograms.
	(Suppress): Set All_Checks, but not Elaboration_Check, for case
	of pragma Suppress (All_Checks)
	(Analyze_Pragma, case Warnings): Implement first argument allowed to be
	a string literal for precise control over warnings.
	Avoid raise of pragma in case of unrecognized pragma and just return
	instead.

	* sem_prag.ads: Minor reformatting

	* switch-c.adb (Scan_Front_End_Switches): Replace "raise Bad_Switch;"
	with call to new procedure Bad_Switch. Call Scan_Pos with new parameter
	Switch. Do not handle any exception.
	Include -gnatwx as part of -gnatg (warn on redundant parens)
	Allow optional = after -gnatm
	(Scan_Front_End_Switches): The -gnatp switch sets All_Checks, but no
	longer sets Elaboration_Checks.
	Code to set warning mode moved to Sem_Warn
	so that it can be shared by pragma processing.

	* s-mastop-tru64.adb (Pop_Frame): Remove redundant parentheses in if
	statement.

	* s-taprop-solaris.adb: 
	Change some <= to =, to avoid new warning

	* a-exexda.adb, prj-proc.adb: 
	Fix obvious typo (Num_Tracebacks compared <= 0 instead of < 0)
	Fix obvious typo (Total_Errors_Detected <= 0 should be = 0)

From-SVN: r106950

gcc/ada/a-exexda.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2005 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2005, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -386,7 +386,7 @@ package body Exception_Data is
       Ptr  : in out Natural)
    is
    begin
-      if X.Num_Tracebacks <= 0 then
+      if X.Num_Tracebacks = 0 then
          return;
       end if;
 

gcc/ada/checks.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2005 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2005, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -2481,13 +2481,11 @@ package body Checks is
             exit when N = Right_Opnd (P)
               and then Nkind (Left_Opnd (P)) = N_Op_Eq;
 
-         --  And/And then case, left operand must be inequality test. Note that
-         --  at this stage, the expander will have changed a/=b to not (a=b).
+         --  And/And then case, left operand must be inequality test
 
          elsif K = N_Op_And or else K = N_And_Then then
             exit when N = Right_Opnd (P)
-              and then Nkind (Left_Opnd (P)) = N_Op_Not
-              and then Nkind (Right_Opnd (Left_Opnd (P))) = N_Op_Eq;
+              and then Nkind (Left_Opnd (P)) = N_Op_Ne;
          end if;
 
          N := P;
@@ -3259,15 +3257,32 @@ package body Checks is
 
    function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is
    begin
+      --  The complication in this routine is that if we are in the dynamic
+      --  model of elaboration, we also check All_Checks, since All_Checks
+      --  does not set Elaboration_Check explicitly.
+
       if Present (E) then
          if Kill_Elaboration_Checks (E) then
             return True;
+
          elsif Checks_May_Be_Suppressed (E) then
-            return Is_Check_Suppressed (E, Elaboration_Check);
+            if Is_Check_Suppressed (E, Elaboration_Check) then
+               return True;
+            elsif Dynamic_Elaboration_Checks then
+               return Is_Check_Suppressed (E, All_Checks);
+            else
+               return False;
+            end if;
          end if;
       end if;
 
-      return Scope_Suppress (Elaboration_Check);
+      if Scope_Suppress (Elaboration_Check) then
+         return True;
+      elsif Dynamic_Elaboration_Checks then
+         return Scope_Suppress (All_Checks);
+      else
+         return False;
+      end if;
    end Elaboration_Checks_Suppressed;
 
    ---------------------------
@@ -3690,6 +3705,15 @@ package body Checks is
       then
          return;
 
+      --  No check on a univeral real constant. The context will eventually
+      --  convert it to a machine number for some target type, or report an
+      --  illegality.
+
+      elsif Nkind (Expr) = N_Real_Literal
+        and then Etype (Expr) = Universal_Real
+      then
+         return;
+
       --  An annoying special case. If this is an out parameter of a scalar
       --  type, then the value is not going to be accessed, therefore it is
       --  inappropriate to do any validity check at the call site.
@@ -3845,11 +3869,10 @@ package body Checks is
       then
          return Expr_Known_Valid (Expression (Expr));
 
-      --  The result of any function call or operator is always considered
-      --  valid, since we assume the necessary checks are done by the call.
-      --  For operators on floating-point operations, we must also check
-      --  when the operation is the right-hand side of an assignment, or
-      --  is an actual in a call.
+      --  The result of any operator is always considered valid, since we
+      --  assume the necessary checks are done by the operator. For operators
+      --  on floating-point operations, we must also check when the operation
+      --  is the right-hand side of an assignment, or is an actual in a call.
 
       elsif
         Nkind (Expr) in N_Binary_Op or else Nkind (Expr) in N_Unary_Op
@@ -3866,9 +3889,6 @@ package body Checks is
             return True;
          end if;
 
-      elsif Nkind (Expr) = N_Function_Call then
-         return True;
-
       --  For all other cases, we do not know the expression is valid
 
       else

gcc/ada/prj-proc.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2001-2005 Free Software Foundation, Inc.          --
+--          Copyright (C) 2001-2005, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -1129,7 +1129,7 @@ package body Prj.Proc is
          end loop;
       end if;
 
-      Success := Total_Errors_Detected <= 0;
+      Success := Total_Errors_Detected = 0;
    end Process;
 
    -------------------------------

gcc/ada/s-mastop-tru64.adb

@@ -7,7 +7,7 @@
 --                                 B o d y                                  --
 --                         (Version for Alpha/Dec Unix)                     --
 --                                                                          --
---           Copyright (C) 1999-2005 Ada Core Technologies, Inc.            --
+--                     Copyright (C) 1999-2005, AdaCore                     --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -143,7 +143,7 @@ package body System.Machine_State_Operations is
       Prf : constant System.Address := exc_lookup_function (Get_Code_Loc (M));
 
    begin
-      if (Prf = System.Null_Address) then
+      if Prf = System.Null_Address then
          c_set_code_loc (M, 0);
       else
          exc_virtual_unwind (Prf, M);

gcc/ada/s-taprop-solaris.adb

@@ -1382,7 +1382,7 @@ package body System.Task_Primitives.Operations is
    begin
       --  Check that caller is abort-deferred
 
-      if Self_ID.Deferral_Level <= 0 then
+      if Self_ID.Deferral_Level = 0 then
          return False;
       end if;
 
@@ -1419,7 +1419,7 @@ package body System.Task_Primitives.Operations is
 
       --  Check that caller is abort-deferred
 
-      if Self_ID.Deferral_Level <= 0 then
+      if Self_ID.Deferral_Level = 0 then
          return False;
       end if;
 
@@ -1498,7 +1498,7 @@ package body System.Task_Primitives.Operations is
    begin
       --  Check that caller is abort-deferred
 
-      if Self_ID.Deferral_Level <= 0 then
+      if Self_ID.Deferral_Level = 0 then
          return False;
       end if;
 
@@ -1617,7 +1617,7 @@ package body System.Task_Primitives.Operations is
 
       --  Check that caller is abort-deferred
 
-      if Self_ID.Deferral_Level <= 0 then
+      if Self_ID.Deferral_Level = 0 then
          return False;
       end if;
 
@@ -1646,7 +1646,7 @@ package body System.Task_Primitives.Operations is
    begin
       --  Check that caller is abort-deferred
 
-      if Self_ID.Deferral_Level <= 0 then
+      if Self_ID.Deferral_Level = 0 then
          return False;
       end if;
 
@@ -1833,7 +1833,7 @@ package body System.Task_Primitives.Operations is
 
       --  Check that caller is abort-deferred
 
-      if Self_ID.Deferral_Level <= 0 then
+      if Self_ID.Deferral_Level = 0 then
          return False;
       end if;
 

gcc/ada/sem_prag.adb

@@ -64,6 +64,7 @@ with Sem_Res;  use Sem_Res;
 with Sem_Type; use Sem_Type;
 with Sem_Util; use Sem_Util;
 with Sem_VFpt; use Sem_VFpt;
+with Sem_Warn; use Sem_Warn;
 with Stand;    use Stand;
 with Sinfo;    use Sinfo;
 with Sinfo.CN; use Sinfo.CN;
@@ -236,8 +237,9 @@ package body Sem_Prag is
 
       Pragma_Exit : exception;
       --  This exception is used to exit pragma processing completely. It
-      --  is used when an error is detected, and in other situations where
-      --  it is known that no further processing is required.
+      --  is used when an error is detected, and no further processing is
+      --  required. It is also used if an earlier error has left the tree
+      --  in a state where the pragma should not be processed.
 
       Arg_Count : Nat;
       --  Number of pragma argument associations
@@ -1336,10 +1338,7 @@ package body Sem_Prag is
                   then
                      Unit_Name := Defining_Entity (Unit_Node);
 
-                  elsif     Unit_Kind = N_Function_Instantiation
-                    or else Unit_Kind = N_Package_Instantiation
-                    or else Unit_Kind = N_Procedure_Instantiation
-                  then
+                  elsif Unit_Kind in N_Generic_Instantiation then
                      Unit_Name := Defining_Entity (Unit_Node);
 
                   else
@@ -3784,9 +3783,21 @@ package body Sem_Prag is
             --  suppress check for any check id value.
 
             if C = All_Checks then
+
+               --  For All_Checks, we set all specific checks with the
+               --  exception of Elaboration_Check, which is handled specially
+               --  because of not wanting All_Checks to have the effect of
+               --  deactivating static elaboration order processing.
+
                for J in Scope_Suppress'Range loop
+                  if J /= Elaboration_Check then
                      Scope_Suppress (J) := Suppress_Case;
+                  end if;
                end loop;
+
+            --  If not All_Checks, just set appropriate entry. Note that we
+            --  will set Elaboration_Check if this is explicitly specified.
+
             else
                Scope_Suppress (C) := Suppress_Case;
             end if;
@@ -4259,7 +4270,7 @@ package body Sem_Prag is
          if Warn_On_Unrecognized_Pragma then
             Error_Pragma ("unrecognized pragma%!?");
          else
-            raise Pragma_Exit;
+            return;
          end if;
       else
          Prag_Id := Get_Pragma_Id (Chars (N));
@@ -5991,7 +6002,7 @@ package body Sem_Prag is
                 Present (Source_Location)
             then
                Error_Pragma
-                 ("parameter profile and source location can not " &
+                 ("parameter profile and source location cannot " &
                   "be used together in pragma%");
             end if;
 
@@ -8141,6 +8152,28 @@ package body Sem_Prag is
             S      : String_Id;
             Active : Boolean := True;
 
+            procedure Check_Obsolete_Subprogram;
+            --  Checks if Subp is a subprogram declaration node, and if so
+            --  replaces Subp by the defining entity of the subprogram. If not,
+            --  issues an error message
+
+            ------------------------------
+            -- Check_Obsolete_Subprogram--
+            ------------------------------
+
+            procedure Check_Obsolete_Subprogram is
+            begin
+               if Nkind (Subp) /= N_Subprogram_Declaration then
+                  Error_Pragma
+                    ("pragma% misplaced, must immediately " &
+                     "follow subprogram/package declaration");
+               else
+                  Subp := Defining_Entity (Subp);
+               end if;
+            end Check_Obsolete_Subprogram;
+
+         --  Start of processing for pragma Obsolescent
+
          begin
             GNAT_Pragma;
             Check_At_Most_N_Arguments (2);
@@ -8153,6 +8186,7 @@ package body Sem_Prag is
 
             if Present (Prev (N)) then
                Subp := Prev (N);
+               Check_Obsolete_Subprogram;
 
             --  Second possibility, stand alone subprogram declaration with the
             --  pragma immediately following the declaration.
@@ -8161,25 +8195,22 @@ package body Sem_Prag is
               and then Nkind (Parent (N)) = N_Compilation_Unit_Aux
             then
                Subp := Unit (Parent (Parent (N)));
+               Check_Obsolete_Subprogram;
 
-            --  Any other possibility is a misplacement
+            --  Only other possibility is library unit placement for package
 
             else
-               Subp := Empty;
-            end if;
-
-            --  Check correct placement
+               Subp := Find_Lib_Unit_Name;
 
-            if Nkind (Subp) /= N_Subprogram_Declaration then
-               Error_Pragma
-                 ("pragma% misplaced, must immediately " &
-                  "follow subprogram spec");
+               if Ekind (Subp) /= E_Package
+                 and then Ekind (Subp) /= E_Generic_Package
+               then
+                  Check_Obsolete_Subprogram;
+               end if;
             end if;
 
             --  If OK placement, acquire arguments
 
-            Subp := Defining_Entity (Subp);
-
             if Arg_Count >= 1 then
 
                --  Deal with static string argument
@@ -9907,8 +9938,7 @@ package body Sem_Prag is
                  ("pragma% requires separate spec and must come before body");
 
             elsif Rep_Item_Too_Early (E, N)
-                 or else
-               Rep_Item_Too_Late (E, N)
+              or else Rep_Item_Too_Late (E, N)
             then
                raise Pragma_Exit;
 
@@ -10346,16 +10376,58 @@ package body Sem_Prag is
          --------------
 
          --  pragma Warnings (On | Off, [LOCAL_NAME])
+         --  pragma Warnings (static_string_EXPRESSION);
 
          when Pragma_Warnings => Warnings : begin
             GNAT_Pragma;
             Check_At_Least_N_Arguments (1);
-            Check_At_Most_N_Arguments (2);
             Check_No_Identifiers;
 
-            --  One argument case was processed by parser in Par.Prag
+            --  One argument case
 
-            if Arg_Count /= 1 then
+            if Arg_Count = 1 then
+               declare
+                  Argx : constant Node_Id := Get_Pragma_Arg (Arg1);
+
+               begin
+                  --  On/Off one argument case was processed by parser
+
+                  if Nkind (Argx) = N_Identifier
+                    and then
+                      (Chars (Argx) = Name_On
+                         or else
+                       Chars (Argx) = Name_Off)
+                  then
+                     null;
+
+                  else
+                     Check_Arg_Is_Static_Expression (Arg1, Standard_String);
+
+                     declare
+                        Lit : constant Node_Id   := Expr_Value_S (Argx);
+                        Str : constant String_Id := Strval (Lit);
+                        C   : Char_Code;
+
+                     begin
+                        for J in 1 .. String_Length (Str) loop
+                           C := Get_String_Char (Str, J);
+
+                           if In_Character_Range (C)
+                             and then Set_Warning_Switch (Get_Character (C))
+                           then
+                              null;
+                           else
+                              Error_Pragma_Arg
+                                ("invalid warning switch character", Arg1);
+                           end if;
+                        end loop;
+                     end;
+                  end if;
+               end;
+
+            --  Two argument case
+
+            elsif Arg_Count /= 1 then
                Check_Arg_Is_One_Of (Arg1, Name_On, Name_Off);
                Check_Arg_Count (2);
 
@@ -10390,8 +10462,8 @@ package body Sem_Prag is
                      return;
                   else
                      loop
-                        Set_Warnings_Off (E,
-                          (Chars (Expression (Arg1)) = Name_Off));
+                        Set_Warnings_Off
+                          (E, (Chars (Expression (Arg1)) = Name_Off));
 
                         if Is_Enumeration_Type (E) then
                            declare
@@ -10410,6 +10482,10 @@ package body Sem_Prag is
                      end loop;
                   end if;
                end;
+
+               --  More than two arguments
+            else
+               Check_At_Most_N_Arguments (2);
             end if;
          end Warnings;
 

gcc/ada/sem_prag.ads

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2004 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2005, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -28,62 +28,62 @@
 --  (logically this processing belongs in chapter 4)
 
 with Types; use Types;
+
 package Sem_Prag is
 
    procedure Analyze_Pragma (N : Node_Id);
    --  Analyze procedure for pragma reference node N
 
    function Delay_Config_Pragma_Analyze (N : Node_Id) return Boolean;
-   --  N is a pragma appearing in a configuration pragma file. Most
-   --  such pragmas are analyzed when the file is read, before parsing
-   --  and analyzing the main unit. However, the analysis of certain
-   --  pragmas results in adding information to the compiled main unit,
-   --  and this cannot be done till the main unit is processed. Such
-   --  pragmas return True from this function and in Frontend pragmas
-   --  where Delay_Config_Pragma_Analyze is True have their analysis
-   --  delayed until after the main program is parsed and analyzed.
+   --  N is a pragma appearing in a configuration pragma file. Most such
+   --  pragmas are analyzed when the file is read, before parsing and analyzing
+   --  the main unit. However, the analysis of certain pragmas results in
+   --  adding information to the compiled main unit, and this cannot be done
+   --  till the main unit is processed. Such pragmas return True from this
+   --  function and in Frontend pragmas where Delay_Config_Pragma_Analyze is
+   --  True have their analysis delayed until after the main program is parsed
+   --  and analyzed.
 
    function Is_Non_Significant_Pragma_Reference (N : Node_Id) return Boolean;
    --  The node N is a node for an entity and the issue is whether the
-   --  occurrence is a reference for the purposes of giving warnings
-   --  about unreferenced variables. This function returns True if the
-   --  reference is not a reference from this point of view (e.g. the
-   --  occurrence in a pragma Pack) and False if it is a real reference
-   --  (e.g. the occcurrence in a pragma Export);
+   --  occurrence is a reference for the purposes of giving warnings about
+   --  unreferenced variables. This function returns True if the reference is
+   --  not a reference from this point of view (e.g. the occurrence in a pragma
+   --  Pack) and False if it is a real reference (e.g. the occcurrence in a
+   --  pragma Export);
 
    function Is_Pragma_String_Literal (Par : Node_Id) return Boolean;
-   --  Given an N_Pragma_Argument_Association node, Par, which has the form
-   --  of an operator symbol, determines whether or not it should be treated
-   --  as an string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol.
-   --  If True is returned, the argument is converted to a string literal. If
+   --  Given an N_Pragma_Argument_Association node, Par, which has the form of
+   --  an operator symbol, determines whether or not it should be treated as an
+   --  string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol. If
+   --  True is returned, the argument is converted to a string literal. If
    --  False is returned, then the argument is treated as an entity reference
    --  to the operator.
 
    function Is_Config_Static_String (Arg : Node_Id) return Boolean;
-   --  This is called for a configuration pragma that requires either a
-   --  string literal or a concatenation of string literals. We cannot
-   --  use normal static string processing because it is too early in
-   --  the case of the pragma appearing in a configuration pragmas file.
-   --  If Arg is of an appropriate form, then this call obtains the string
-   --  (doing any necessary concatenations) and places it in Name_Buffer,
-   --  setting Name_Len to its length, and then returns True. If it is
-   --  not of the correct form, then an appropriate error message is
-   --  posted, and False is returned.
+   --  This is called for a configuration pragma that requires either string
+   --  literal or a concatenation of string literals. We cannot use normal
+   --  static string processing because it is too early in the case of the
+   --  pragma appearing in a configuration pragmas file. If Arg is of an
+   --  appropriate form, then this call obtains the string (doing any necessary
+   --  concatenations) and places it in Name_Buffer, setting Name_Len to its
+   --  length, and then returns True. If it is not of the correct form, then an
+   --  appropriate error message is posted, and False is returned.
 
    procedure Process_Compilation_Unit_Pragmas (N : Node_Id);
-   --  Called at the start of processing compilation unit N to deal with
-   --  any special issues regarding pragmas. In particular, we have to
-   --  deal with Suppress_All at this stage, since it appears after the
-   --  unit instead of before.
+   --  Called at the start of processing compilation unit N to deal with any
+   --  special issues regarding pragmas. In particular, we have to deal with
+   --  Suppress_All at this stage, since it appears after the unit instead of
+   --  before.
 
    procedure Set_Encoded_Interface_Name (E : Entity_Id; S : Node_Id);
-   --  This routine is used to set an encoded interface name. The node
-   --  S is an N_String_Literal node for the external name to be set, and
-   --  E is an entity whose Interface_Name field is to be set. In the
-   --  normal case where S contains a name that is a valid C identifier,
-   --  then S is simply set as the value of the Interface_Name. Otherwise
-   --  it is encoded. See the body for details of the encoding. This
-   --  encoding is only done on VMS systems, since it seems pretty silly,
-   --  but is needed to pass some dubious tests in the test suite.
+   --  This routine is used to set an encoded interface name. The node S is an
+   --  N_String_Literal node for the external name to be set, and E is an
+   --  entity whose Interface_Name field is to be set. In the normal case where
+   --  S contains a name that is a valid C identifier, then S is simply set as
+   --  the value of the Interface_Name. Otherwise it is encoded. See the body
+   --  for details of the encoding. This encoding is only done on VMS systems,
+   --  since it seems pretty silly, but is needed to pass some dubious tests in
+   --  the test suite.
 
 end Sem_Prag;

gcc/ada/types.ads

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2005 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2005, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -311,14 +311,14 @@ package Types is
    --  is in practice infinite and there is no need to check the range.
 
    Ureal_Low_Bound : constant := 500_000_000;
-   --  Low bound for Ureal values.
+   --  Low bound for Ureal values
 
    Ureal_High_Bound : constant := 599_999_999;
    --  Maximum number of Ureal values stored is 100_000_000 which is in
    --  practice infinite so that no check is required.
 
    Uint_Low_Bound : constant := 600_000_000;
-   --  Low bound for Uint values.
+   --  Low bound for Uint values
 
    Uint_Table_Start : constant := 2_000_000_000;
    --  Location where table entries for universal integers start (see
@@ -479,7 +479,7 @@ package Types is
    --  are not valid.
 
    First_Elist_Id : constant Elist_Id := No_Elist + 1;
-   --  Subscript of first allocated Elist header.
+   --  Subscript of first allocated Elist header
 
    --  Element Id values are used to identify individual elements of an
    --  element list (see package Elists for further details).
@@ -696,12 +696,19 @@ package Types is
       Tag_Check,
       All_Checks);
 
-   --  The following record contains an entry for each recognized check name
+   --  The following array contains an entry for each recognized check name
    --  for pragma Suppress. It is used to represent current settings of scope
    --  based suppress actions from pragma Suppress or command line settings.
 
-   type Suppress_Array is
-     array (Check_Id range Access_Check .. Tag_Check) of Boolean;
+   --  Note: when Suppress_Array (All_Checks) is True, then generally all other
+   --  specific check entries are set True, except for the Elaboration_Check
+   --  entry which is set only if an explicit Suppress for this check is given.
+   --  The reason for this non-uniformity is that we do not want All_Checks to
+   --  suppress elaboration checking when using the static elaboration model.
+   --  We recognize only an explicit suppress of Elaboration_Check as a signal
+   --  that the static elaboration checking should skip a compile time check.
+
+   type Suppress_Array is array (Check_Id) of Boolean;
    pragma Pack (Suppress_Array);
 
    --  To add a new check type to GNAT, the following steps are required: