gcc/ada/s-stalib.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --              S Y S T E M . S T A N D A R D _ L I B R A R Y               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2015, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This package is included in all programs. It contains declarations that
  33 --  are required to be part of every Ada program. A special mechanism is
  34 --  required to ensure that these are loaded, since it may be the case in
  35 --  some programs that the only references to these required packages are
  36 --  from C code or from code generated directly by Gigi, and in both cases
  37 --  the binder is not aware of such references.
  38
  39 --  System.Standard_Library also includes data that must be present in every
  40 --  program, in particular data for all the standard exceptions, and also some
  41 --  subprograms that must be present in every program.
  42
  43 --  The binder unconditionally includes s-stalib.ali, which ensures that this
  44 --  package and the packages it references are included in all Ada programs,
  45 --  together with the included data.
  46
  47 pragma Compiler_Unit_Warning;
  48
  49 pragma Polling (Off);
  50 --  We must turn polling off for this unit, because otherwise we get
  51 --  elaboration circularities with Ada.Exceptions if polling is on.
  52
  53 with Ada.Unchecked_Conversion;
  54
  55 package System.Standard_Library is
  56    pragma Warnings (Off);
  57    pragma Preelaborate;
  58    pragma Warnings (On);
  59
  60    subtype Big_String is String (1 .. Positive'Last);
  61    pragma Suppress_Initialization (Big_String);
  62    --  Type used to obtain string access to given address. Initialization is
  63    --  suppressed, since we never want to have variables of this type, and
  64    --  we never want to attempt initialiazation of virtual variables of this
  65    --  type (e.g. when pragma Normalize_Scalars is used).
  66
  67    type Big_String_Ptr is access all Big_String;
  68    for Big_String_Ptr'Storage_Size use 0;
  69    --  We use this access type to pass a pointer to an area of storage to be
  70    --  accessed as a string. Of course when this pointer is used, it is the
  71    --  responsibility of the accessor to ensure proper bounds. The storage
  72    --  size clause ensures we do not allocate variables of this type.
  73
  74    function To_Ptr is
  75      new Ada.Unchecked_Conversion (System.Address, Big_String_Ptr);
  76
  77    -------------------------------------
  78    -- Exception Declarations and Data --
  79    -------------------------------------
  80
  81    type Raise_Action is access procedure;
  82    --  A pointer to a procedure used in the Raise_Hook field
  83
  84    type Exception_Data;
  85    type Exception_Data_Ptr is access all Exception_Data;
  86    --  An equivalent of Exception_Id that is public
  87
  88    --  The following record defines the underlying representation of exceptions
  89
  90    --  WARNING: Any changes to this may need to be reflected in the following
  91    --  locations in the compiler and runtime code:
  92
  93    --    1. The Internal_Exception routine in s-exctab.adb
  94    --    2. The processing in gigi that tests Not_Handled_By_Others
  95    --    3. Expand_N_Exception_Declaration in Exp_Ch11
  96    --    4. The construction of the exception type in Cstand
  97
  98    type Exception_Data is record
  99       Not_Handled_By_Others : Boolean;
 100       --  Normally set False, indicating that the exception is handled in the
 101       --  usual way by others (i.e. an others handler handles the exception).
 102       --  Set True to indicate that this exception is not caught by others
 103       --  handlers, but must be explicitly named in a handler. This latter
 104       --  setting is currently used by the Abort_Signal.
 105
 106       Lang : Character;
 107       --  A character indicating the language raising the exception.
 108       --  Set to "A" for exceptions defined by an Ada program.
 109       --  Set to "C" for imported C++ exceptions.
 110
 111       Name_Length : Natural;
 112       --  Length of fully expanded name of exception
 113
 114       Full_Name : System.Address;
 115       --  Fully expanded name of exception, null terminated
 116       --  You can use To_Ptr to convert this to a string.
 117
 118       HTable_Ptr : Exception_Data_Ptr;
 119       --  Hash table pointer used to link entries together in the hash table
 120       --  built (by Register_Exception in s-exctab.adb) for converting between
 121       --  identities and names.
 122
 123       Foreign_Data : Address;
 124       --  Data for imported exceptions. Not used in the Ada case. This
 125       --  represents the address of the RTTI for the C++ case.
 126
 127       Raise_Hook : Raise_Action;
 128       --  This field can be used to place a "hook" on an exception. If the
 129       --  value is non-null, then it points to a procedure which is called
 130       --  whenever the exception is raised. This call occurs immediately,
 131       --  before any other actions taken by the raise (and in particular
 132       --  before any unwinding of the stack occurs).
 133    end record;
 134
 135    --  Definitions for standard predefined exceptions defined in Standard,
 136
 137    --  Why are the NULs necessary here, seems like they should not be
 138    --  required, since Gigi is supposed to add a Nul to each name ???
 139
 140    Constraint_Error_Name : constant String := "CONSTRAINT_ERROR" & ASCII.NUL;
 141    Program_Error_Name    : constant String := "PROGRAM_ERROR"    & ASCII.NUL;
 142    Storage_Error_Name    : constant String := "STORAGE_ERROR"    & ASCII.NUL;
 143    Tasking_Error_Name    : constant String := "TASKING_ERROR"    & ASCII.NUL;
 144    Abort_Signal_Name     : constant String := "_ABORT_SIGNAL"    & ASCII.NUL;
 145
 146    Numeric_Error_Name    : constant String := "NUMERIC_ERROR"    & ASCII.NUL;
 147    --  This is used only in the Ada 83 case, but it is not worth having a
 148    --  separate version of s-stalib.ads for use in Ada 83 mode.
 149
 150    Constraint_Error_Def : aliased Exception_Data :=
 151      (Not_Handled_By_Others => False,
 152       Lang                  => 'A',
 153       Name_Length           => Constraint_Error_Name'Length,
 154       Full_Name             => Constraint_Error_Name'Address,
 155       HTable_Ptr            => null,
 156       Foreign_Data          => Null_Address,
 157       Raise_Hook            => null);
 158
 159    Numeric_Error_Def : aliased Exception_Data :=
 160      (Not_Handled_By_Others => False,
 161       Lang                  => 'A',
 162       Name_Length           => Numeric_Error_Name'Length,
 163       Full_Name             => Numeric_Error_Name'Address,
 164       HTable_Ptr            => null,
 165       Foreign_Data          => Null_Address,
 166       Raise_Hook            => null);
 167
 168    Program_Error_Def : aliased Exception_Data :=
 169      (Not_Handled_By_Others => False,
 170       Lang                  => 'A',
 171       Name_Length           => Program_Error_Name'Length,
 172       Full_Name             => Program_Error_Name'Address,
 173       HTable_Ptr            => null,
 174       Foreign_Data          => Null_Address,
 175       Raise_Hook            => null);
 176
 177    Storage_Error_Def : aliased Exception_Data :=
 178      (Not_Handled_By_Others => False,
 179       Lang                  => 'A',
 180       Name_Length           => Storage_Error_Name'Length,
 181       Full_Name             => Storage_Error_Name'Address,
 182       HTable_Ptr            => null,
 183       Foreign_Data          => Null_Address,
 184       Raise_Hook            => null);
 185
 186    Tasking_Error_Def : aliased Exception_Data :=
 187      (Not_Handled_By_Others => False,
 188       Lang                  => 'A',
 189       Name_Length           => Tasking_Error_Name'Length,
 190       Full_Name             => Tasking_Error_Name'Address,
 191       HTable_Ptr            => null,
 192       Foreign_Data          => Null_Address,
 193       Raise_Hook            => null);
 194
 195    Abort_Signal_Def : aliased Exception_Data :=
 196      (Not_Handled_By_Others => True,
 197       Lang                  => 'A',
 198       Name_Length           => Abort_Signal_Name'Length,
 199       Full_Name             => Abort_Signal_Name'Address,
 200       HTable_Ptr            => null,
 201       Foreign_Data          => Null_Address,
 202       Raise_Hook            => null);
 203
 204    pragma Export (C, Constraint_Error_Def, "constraint_error");
 205    pragma Export (C, Numeric_Error_Def,    "numeric_error");
 206    pragma Export (C, Program_Error_Def,    "program_error");
 207    pragma Export (C, Storage_Error_Def,    "storage_error");
 208    pragma Export (C, Tasking_Error_Def,    "tasking_error");
 209    pragma Export (C, Abort_Signal_Def,     "_abort_signal");
 210
 211    Local_Partition_ID : Natural := 0;
 212    --  This variable contains the local Partition_ID that will be used when
 213    --  building exception occurrences. In distributed mode, it will be
 214    --  set by each partition to the correct value during the elaboration.
 215
 216    type Exception_Trace_Kind is
 217      (RM_Convention,
 218       --  No particular trace is requested, only unhandled exceptions
 219       --  in the environment task (following the RM) will be printed.
 220       --  This is the default behavior.
 221
 222       Every_Raise,
 223       --  Denotes every possible raise event, either explicit or due to
 224       --  a specific language rule, within the context of a task or not.
 225
 226       Unhandled_Raise
 227       --  Denotes the raise events corresponding to exceptions for which
 228       --  there is no user defined handler.
 229      );
 230    --  Provide a way to denote different kinds of automatic traces related
 231    --  to exceptions that can be requested.
 232
 233    Exception_Trace : Exception_Trace_Kind := RM_Convention;
 234    pragma Atomic (Exception_Trace);
 235    --  By default, follow the RM convention
 236
 237    -----------------
 238    -- Subprograms --
 239    -----------------
 240
 241    procedure Abort_Undefer_Direct;
 242    pragma Inline (Abort_Undefer_Direct);
 243    --  A little procedure that just calls Abort_Undefer.all, for use in
 244    --  clean up procedures, which only permit a simple subprogram name.
 245
 246    procedure Adafinal;
 247    --  Performs the Ada Runtime finalization the first time it is invoked.
 248    --  All subsequent calls are ignored.
 249
 250 end System.Standard_Library;