[Ada] Remove "constant" attribute on Osint.Unknown_Attributes

2018-05-25  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* exp_aggr.adb (Convert_To_Positional): Bump default for
	Max_Others_Replicate to 32. Update comments.
	* osint.ads (Unknown_Attributes): No longer pretend this is a constant.
	(No_File_Info_Cache): Initialize separately.
	* osint.adb (No_File_Info_Cache): Update initializer.

From-SVN: r260739

gcc/ada/ChangeLog

+2018-05-25  Arnaud Charlet  <charlet@adacore.com>
+
+	* exp_aggr.adb (Convert_To_Positional): Bump default for
+	Max_Others_Replicate to 32. Update comments.
+	* osint.ads (Unknown_Attributes): No longer pretend this is a constant.
+	(No_File_Info_Cache): Initialize separately.
+	* osint.adb (No_File_Info_Cache): Update initializer.
+
 2018-05-25  Javier Miranda  <miranda@adacore.com>
 
 	* sem_res.adb (Resolve_Membership_Op): Allow the use of the membership

gcc/ada/exp_aggr.adb

@@ -284,14 +284,14 @@ package body Exp_Aggr is
 
    procedure Convert_To_Positional
      (N                    : Node_Id;
-      Max_Others_Replicate : Nat     := 5;
+      Max_Others_Replicate : Nat     := 32;
       Handle_Bit_Packed    : Boolean := False);
    --  If possible, convert named notation to positional notation. This
    --  conversion is possible only in some static cases. If the conversion is
    --  possible, then N is rewritten with the analyzed converted aggregate.
    --  The parameter Max_Others_Replicate controls the maximum number of
    --  values corresponding to an others choice that will be converted to
-   --  positional notation (the default of 5 is the normal limit, and reflects
+   --  positional notation (the default of 32 is the normal limit, and reflects
    --  the fact that normally the loop is better than a lot of separate
    --  assignments). Note that this limit gets overridden in any case if
    --  either of the restrictions No_Elaboration_Code or No_Implicit_Loops is
@@ -301,11 +301,6 @@ package body Exp_Aggr is
    --  Packed_Array_Aggregate_Handled, we set this parameter to True, since
    --  these are cases we handle in there.
 
-   --  It would seem useful to have a higher default for Max_Others_Replicate,
-   --  but aggregates in the compiler make this impossible: the compiler
-   --  bootstrap fails if Max_Others_Replicate is greater than 25. This
-   --  is unexpected ???
-
    procedure Expand_Array_Aggregate (N : Node_Id);
    --  This is the top-level routine to perform array aggregate expansion.
    --  N is the N_Aggregate node to be expanded.
@@ -4296,7 +4291,7 @@ package body Exp_Aggr is
 
    procedure Convert_To_Positional
      (N                    : Node_Id;
-      Max_Others_Replicate : Nat     := 5;
+      Max_Others_Replicate : Nat     := 32;
       Handle_Bit_Packed    : Boolean := False)
    is
       Typ : constant Entity_Id := Etype (N);

gcc/ada/osint.adb

@@ -250,8 +250,7 @@ package body Osint is
       Attr : aliased File_Attributes;
    end record;
 
-   No_File_Info_Cache : constant File_Info_Cache :=
-                          (No_File, Unknown_Attributes);
+   No_File_Info_Cache : constant File_Info_Cache := (No_File, (others => 0));
 
    package File_Name_Hash_Table is new GNAT.HTable.Simple_HTable (
      Header_Num => File_Hash_Num,

gcc/ada/osint.ads

@@ -255,10 +255,26 @@ package Osint is
    --  from the disk and then cached in the File_Attributes parameter (possibly
    --  along with other values).
 
-   type File_Attributes is private;
-   Unknown_Attributes : constant File_Attributes;
+   File_Attributes_Size : constant Natural := 32;
+   --  This should be big enough to fit a "struct file_attributes" on any
+   --  system. It doesn't cause any malfunction if it is too big (which avoids
+   --  the need for either mapping the struct exactly or importing the sizeof
+   --  from C, which would result in dynamic code). However, it does waste
+   --  space (e.g. when a component of this type appears in a record, if it is
+   --  unnecessarily large). Note: for runtime units, use System.OS_Constants.
+   --  SIZEOF_struct_file_attributes instead, which has the exact value.
+
+   type File_Attributes is
+     array (1 .. File_Attributes_Size)
+       of System.Storage_Elements.Storage_Element;
+   for File_Attributes'Alignment use Standard'Maximum_Alignment;
+
+   Unknown_Attributes : File_Attributes;
    --  A cache for various attributes for a file (length, accessibility,...)
-   --  This must be initialized to Unknown_Attributes prior to the first call.
+   --  Will be initialized properly at elaboration (for efficiency later on,
+   --  avoid function calls every time we want to reset the attributes) prior
+   --  to the first usage. We cannot make it constant since the compiler may
+   --  put it in a read-only section.
 
    function Is_Directory
      (Name : C_File_Name;
@@ -754,22 +770,4 @@ private
    --  detected, the file being written is deleted, and a fatal error is
    --  signalled.
 
-   File_Attributes_Size : constant Natural := 32;
-   --  This should be big enough to fit a "struct file_attributes" on any
-   --  system. It doesn't cause any malfunction if it is too big (which avoids
-   --  the need for either mapping the struct exactly or importing the sizeof
-   --  from C, which would result in dynamic code). However, it does waste
-   --  space (e.g. when a component of this type appears in a record, if it is
-   --  unnecessarily large). Note: for runtime units, use System.OS_Constants.
-   --  SIZEOF_struct_file_attributes instead, which has the exact value.
-
-   type File_Attributes is
-     array (1 .. File_Attributes_Size)
-       of System.Storage_Elements.Storage_Element;
-   for File_Attributes'Alignment use Standard'Maximum_Alignment;
-
-   Unknown_Attributes : constant File_Attributes := (others => 0);
-   --  Will be initialized properly at elaboration (for efficiency later on,
-   --  avoid function calls every time we want to reset the attributes).
-
 end Osint;