2008-07-31 Hristian Kirtchev <kirtchev@adacore.com>

	* bindgen.adb Comment reformatting. Update the list of run-time globals.
	(Gen_Adainit_Ada): Add the declaration, import and value set for
	configuration flag Canonical_Streams.
	(Gen_Adainit_C): Add the declaration and initial value of external
	symbol __gl_canonical_streams.
	
	* init.c: Update the list of global values computed by the binder.
	
	* opt.ads: Add flag Canonical_Streams.
	
	* par-prag.adb (Prag): Include Pragma_Canonical_Streams to the list of
	semantically handled pragmas.
	
	* sem_prag.adb: Add an entry into enumeration type Sig_Flags.
	(Analyze_Pragma): Add case for pragma Canonical_Streams.
	
	* snames.adb: Add character value for name Canonical_Streams.
	
	* snames.ads:
	Add Name_Canonical_Streams to the list of configuration pragmas.
	Add Pragma_Canonical_Streams to enumeration type Pragma_Id.
	
	* snames.h: Add a definition for Pragma_Canonical_Streams.
	
	* s-ststop.adb:
	Add a flag and import to seize the value of external symbol
	__gl_canonical_streams. Update comment and initial value of constant
	Use_Block_IO.
	
	* gnat_rm.texi: Add section of pragma Canonical_Streams.
	
	* gnat_ugn.texi:
	Add pragma Canonical_Streams to the list of configuration pragmas.

From-SVN: r138407

gcc/ada/bindgen.adb

@@ -126,39 +126,39 @@ package body Bindgen is
    --     Detect_Blocking               : Integer;
    --     Default_Stack_Size            : Integer;
    --     Leap_Seconds_Support          : Integer;
-
-   --  Main_Priority is the priority value set by pragma Priority in the
-   --  main program. If no such pragma is present, the value is -1.
-
-   --  Time_Slice_Value is the time slice value set by pragma Time_Slice
-   --  in the main program, or by the use of a -Tnnn parameter for the
-   --  binder (if both are present, the binder value overrides). The
-   --  value is in milliseconds. A value of zero indicates that time
-   --  slicing should be suppressed. If no pragma is present, and no
-   --  -T switch was used, the value is -1.
-
-   --  WC_Encoding shows the wide character encoding method used for
-   --  the main program. This is one of the encoding letters defined
-   --  in System.WCh_Con.WC_Encoding_Letters.
-
-   --  Locking_Policy is a space if no locking policy was specified
-   --  for the partition. If a locking policy was specified, the value
-   --  is the upper case first character of the locking policy name,
-   --  for example, 'C' for Ceiling_Locking.
-
-   --  Queuing_Policy is a space if no queuing policy was specified
-   --  for the partition. If a queuing policy was specified, the value
-   --  is the upper case first character of the queuing policy name
-   --  for example, 'F' for FIFO_Queuing.
-
-   --  Task_Dispatching_Policy is a space if no task dispatching policy
-   --  was specified for the partition. If a task dispatching policy
-   --  was specified, the value is the upper case first character of
-   --  the policy name, e.g. 'F' for FIFO_Within_Priorities.
-
-   --  Priority_Specific_Dispatching is the address of a string used to
-   --  store the task dispatching policy specified for the different priorities
-   --  in the partition. The length of this string is determined by the last
+   --     Canonical_Streams             : Integer;
+
+   --  Main_Priority is the priority value set by pragma Priority in the main
+   --  program. If no such pragma is present, the value is -1.
+
+   --  Time_Slice_Value is the time slice value set by pragma Time_Slice in the
+   --  main program, or by the use of a -Tnnn parameter for the binder (if both
+   --  are present, the binder value overrides). The value is in milliseconds.
+   --  A value of zero indicates that time slicing should be suppressed. If no
+   --  pragma is present, and no -T switch was used, the value is -1.
+
+   --  WC_Encoding shows the wide character encoding method used for the main
+   --  program. This is one of the encoding letters defined in
+   --  System.WCh_Con.WC_Encoding_Letters.
+
+   --  Locking_Policy is a space if no locking policy was specified for the
+   --  partition. If a locking policy was specified, the value is the upper
+   --  case first character of the locking policy name, for example, 'C' for
+   --  Ceiling_Locking.
+
+   --  Queuing_Policy is a space if no queuing policy was specified for the
+   --  partition. If a queuing policy was specified, the value is the upper
+   --  case first character of the queuing policy name for example, 'F' for
+   --  FIFO_Queuing.
+
+   --  Task_Dispatching_Policy is a space if no task dispatching policy was
+   --  specified for the partition. If a task dispatching policy was specified,
+   --  the value is the upper case first character of the policy name, e.g. 'F'
+   --  for FIFO_Within_Priorities.
+
+   --  Priority_Specific_Dispatching is the address of a string used to store
+   --  the task dispatching policy specified for the different priorities in
+   --  the partition. The length of this string is determined by the last
    --  priority for which such a pragma applies (the string will be a null
    --  string if no specific dispatching policies were used). If pragma were
    --  present, the entries apply to the priorities in sequence from the first
@@ -182,12 +182,12 @@ package body Bindgen is
    --  such a pragma is given (the string will be a null string if no pragmas
    --  were used). If pragma were present the entries apply to the interrupts
    --  in sequence from the first interrupt, and are set to one of four
-   --  possible settings: 'n' for not specified, 'u' for user, 'r' for
-   --  run time, 's' for system, see description of Interrupt_State pragma
-   --  for further details.
+   --  possible settings: 'n' for not specified, 'u' for user, 'r' for run
+   --  time, 's' for system, see description of Interrupt_State pragma for
+   --  further details.
 
-   --  Num_Interrupt_States is the length of the Interrupt_States string.
-   --  It will be set to zero if no Interrupt_State pragmas are present.
+   --  Num_Interrupt_States is the length of the Interrupt_States string. It
+   --  will be set to zero if no Interrupt_State pragmas are present.
 
    --  Unreserve_All_Interrupts is set to one if at least one unit in the
    --  partition had a pragma Unreserve_All_Interrupts, and zero otherwise.
@@ -201,18 +201,21 @@ package body Bindgen is
    --  this partition, and to zero if longjmp/setjmp exceptions are used.
    --  the use of zero
 
-   --  Detect_Blocking indicates whether pragma Detect_Blocking is
-   --  active or not. A value of zero indicates that the pragma is not
-   --  present, while a value of 1 signals its presence in the
-   --  partition.
+   --  Detect_Blocking indicates whether pragma Detect_Blocking is active or
+   --  not. A value of zero indicates that the pragma is not present, while a
+   --  value of 1 signals its presence in the partition.
 
-   --  Default_Stack_Size is the default stack size used when creating an
-   --  Ada task with no explicit Storize_Size clause.
+   --  Default_Stack_Size is the default stack size used when creating an Ada
+   --  task with no explicit Storize_Size clause.
 
    --  Leap_Seconds_Support denotes whether leap seconds have been enabled or
    --  disabled. A value of zero indicates that leap seconds are turned "off",
    --  while a value of one signifies "on" status.
 
+   --  Canonical_Streams indicates whether stream-related optimizations are
+   --  active. A value of zero indicates that all optimizations are active,
+   --  while a value of one signifies that they have been disabled.
+
    -----------------------
    -- Local Subprograms --
    -----------------------
@@ -593,6 +596,9 @@ package body Bindgen is
          WBI ("      Leap_Seconds_Support : Integer;");
          WBI ("      pragma Import (C, Leap_Seconds_Support, " &
               """__gl_leap_seconds_support"");");
+         WBI ("      Canonical_Streams : Integer;");
+         WBI ("      pragma Import (C, Canonical_Streams, " &
+              """__gl_canonical_streams"");");
 
          --  Import entry point for elaboration time signal handler
          --  installation, and indication of if it's been called previously.
@@ -761,6 +767,17 @@ package body Bindgen is
          Set_String (";");
          Write_Statement_Buffer;
 
+         Set_String ("      Canonical_Streams := ");
+
+         if Canonical_Streams then
+            Set_Int (1);
+         else
+            Set_Int (0);
+         end if;
+
+         Set_String (";");
+         Write_Statement_Buffer;
+
          --  Generate call to Install_Handler
 
          WBI ("");
@@ -1042,6 +1059,18 @@ package body Bindgen is
          Set_String (";");
          Write_Statement_Buffer;
 
+         WBI ("   extern int __gl_canonical_streams;");
+         Set_String ("   __gl_canonical_streams = ");
+
+         if Canonical_Streams then
+            Set_Int (1);
+         else
+            Set_Int (0);
+         end if;
+
+         Set_String (";");
+         Write_Statement_Buffer;
+
          WBI ("");
 
          --  Install elaboration time signal handler

gcc/ada/gnat_rm.texi

@@ -104,6 +104,7 @@ Implementation Defined Pragmas
 * Pragma Assert::
 * Pragma Ast_Entry::
 * Pragma C_Pass_By_Copy::
+* Pragma Canonical_Streams::
 * Pragma Check::
 * Pragma Check_Name::
 * Pragma Check_Policy::
@@ -705,6 +706,7 @@ consideration, the use of these pragmas should be minimized.
 * Pragma Assert::
 * Pragma Ast_Entry::
 * Pragma C_Pass_By_Copy::
+* Pragma Canonical_Streams::
 * Pragma Check::
 * Pragma Check_Name::
 * Pragma Check_Policy::
@@ -1057,6 +1059,27 @@ You can also pass records by copy by specifying the convention
 @code{Import} and @code{Export} pragmas, which allow specification of
 passing mechanisms on a parameter by parameter basis.
 
+@node Pragma Canonical_Streams
+@unnumberedsec Canonical Streams
+@cindex Canonical streams
+@findex Canonical_Streams
+@noindent
+Syntax:
+@smallexample @c ada
+pragma Canonical_Streams;
+@end smallexample
+
+@noindent
+This configuration pragma affects the behavior of stream attributes of any 
+@code{String}, @code{Wide_String} or @code{Wide_Wide_String} based type. When 
+this pragma is present, @code{'Input}, @code{'Output}, @code{'Read} and 
+@code{'Write} exibit Ada 95 canonical behavior, in other words, streaming of 
+values is done character by character.
+
+@noindent
+The use of this pragma is intended to bypass any implementation-related 
+optimizations allowed by Ada 2005 RM 13.13.2 (56/2) Implementation Permission.
+
 @node Pragma Check
 @unnumberedsec Pragma Check
 @cindex Assertions

gcc/ada/gnat_ugn.texi

@@ -10925,6 +10925,7 @@ recognized by GNAT:
    Ada_2005
    Assertion_Policy
    C_Pass_By_Copy
+   Canonical_Streams
    Check_Name
    Check_Policy
    Compile_Time_Error

gcc/ada/init.c

@@ -102,6 +102,7 @@ int   __gl_zero_cost_exceptions          = 0;
 int   __gl_detect_blocking               = 0;
 int   __gl_default_stack_size            = -1;
 int   __gl_leap_seconds_support          = 0;
+int   __gl_canonical_streams             = 0;
 
 /* Indication of whether synchronous signal handler has already been
    installed by a previous call to adainit.  */

gcc/ada/opt.ads

@@ -283,6 +283,11 @@ package Opt is
    --  is set True, or if pragma No_Run_Time is used. See the spec of Rtsfind
    --  for details on the handling of the latter pragma.
 
+   Canonical_Streams : Boolean := False;
+   --  GNATBIND
+   --  Set to True if configuration pragma Canonical_Streams is present. It
+   --  controls the canonical behaviour of stream operations for String types.
+
    Constant_Condition_Warnings : Boolean := False;
    --  GNAT
    --  Set to True to activate warnings on constant conditions

gcc/ada/par-prag.adb

@@ -1054,6 +1054,7 @@ begin
            Pragma_Atomic                        |
            Pragma_Atomic_Components             |
            Pragma_Attach_Handler                |
+           Pragma_Canonical_Streams             |
            Pragma_Check                         |
            Pragma_Check_Name                    |
            Pragma_Check_Policy                  |

gcc/ada/s-ststop.adb

@@ -92,12 +92,23 @@ package body System.Strings.Stream_Ops is
 
       subtype String_Block is String_Type (1 .. C_In_Default_Block);
 
-      --  Block IO is used when the low level can support block IO and the size
-      --  of the character type is a multiple of the stream element type.
+      Flag : Integer;
+      pragma Import (C, Flag, "__gl_canonical_streams");
+      --  This imported value is used to determine whether configuration pragma
+      --  Canonical_Streams is present. A value of zero indicates whether any
+      --  stream-related optimizations are enabled, while a value of one
+      --  indicates a disabled status.
+
+      Canonical_Streams : constant Boolean := Flag = 1;
+
+      --  Block IO is used when the low level can support block IO, the size
+      --  of the character type is a multiple of the stream element type and
+      --  the compilation can use stream optimizations.
 
       Use_Block_IO : constant Boolean :=
                        Stream_Attributes.Block_IO_OK
-                         and then C_Size mod SE_Size = 0;
+                         and then C_Size mod SE_Size = 0
+                         and then not Canonical_Streams;
 
       --  Conversions to and from Default_Block
 

gcc/ada/sem_prag.adb

@@ -5540,6 +5540,18 @@ package body Sem_Prag is
             end if;
          end C_Pass_By_Copy;
 
+         -----------------------
+         -- Canonical_Streams --
+         -----------------------
+
+         --  pragma Canonical_Streams;
+
+         when Pragma_Canonical_Streams =>
+            GNAT_Pragma;
+            Check_Arg_Count (0);
+            Check_Valid_Configuration_Pragma;
+            Canonical_Streams := True;
+
          -----------
          -- Check --
          -----------
@@ -12081,6 +12093,7 @@ package body Sem_Prag is
       Pragma_Atomic                        =>  0,
       Pragma_Atomic_Components             =>  0,
       Pragma_Attach_Handler                => -1,
+      Pragma_Canonical_Streams             => -1,
       Pragma_Check                         => 99,
       Pragma_Check_Name                    =>  0,
       Pragma_Check_Policy                  =>  0,

gcc/ada/snames.adb

@@ -183,6 +183,7 @@ package body Snames is
      "ada_2005#" &
      "assertion_policy#" &
      "c_pass_by_copy#" &
+     "canonical_streams#" &
      "check_name#" &
      "check_policy#" &
      "compile_time_error#" &