gcc/ada/restrict.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             R E S T R I C T                              --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                            $Revision: 1.1 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  12 --                                                                          --
  13 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- GNAT was originally developed  by the GNAT team at  New York University. --
  25 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  26 --                                                                          --
  27 ------------------------------------------------------------------------------
  28
  29 --  This package deals with the implementation of the Restrictions pragma
  30
  31 with Rident;
  32 with Types;  use Types;
  33 with Uintp;  use Uintp;
  34
  35 package Restrict is
  36
  37    type Restriction_Id is new Rident.Restriction_Id;
  38    --  The type Restriction_Id defines the set of restriction identifiers,
  39    --  which take no parameter (i.e. they are either present or not present).
  40    --  The actual definition is in the separate package Rident, so that it
  41    --  can easily be accessed by the binder without dragging in lots of stuff.
  42
  43    subtype Partition_Restrictions is
  44      Restriction_Id range
  45        Restriction_Id (Rident.Partition_Restrictions'First) ..
  46        Restriction_Id (Rident.Partition_Restrictions'Last);
  47    --  Range of restriction identifiers that are checked by the binder
  48
  49    subtype Compilation_Unit_Restrictions is
  50      Restriction_Id range
  51        Restriction_Id (Rident.Compilation_Unit_Restrictions'First) ..
  52        Restriction_Id (Rident.Compilation_Unit_Restrictions'Last);
  53    --  Range of restriction identifiers not checked by binder
  54
  55    type Restriction_Parameter_Id is new Rident.Restriction_Parameter_Id;
  56    --  The type Restriction_Parameter_Id records cases where a parameter is
  57    --  present in the corresponding pragma. These cases are not checked for
  58    --  consistency by the binder. The actual definition is in the separate
  59    --  package Rident for consistency.
  60
  61    type Restrictions_Flags is array (Restriction_Id) of Boolean;
  62    --  Type used for arrays indexed by Restriction_Id.
  63
  64    Restrictions : Restrictions_Flags := (others => False);
  65    --  Corresponding entry is False if restriction is not active, and
  66    --  True if the restriction is active, i.e. if a pragma Restrictions
  67    --  has been seen anywhere. Note that we are happy to pick up any
  68    --  restrictions pragmas in with'ed units, since we are required to
  69    --  be consistent at link time, and we might as well find the error
  70    --  at compile time. Clients must NOT use this array for checking to
  71    --  see if a restriction is violated, instead it is required that the
  72    --  Check_Restrictions subprograms be used for this purpose. The only
  73    --  legitimate direct use of this array is when the code is modified
  74    --  as a result of the restriction in some way.
  75
  76    Restrictions_Loc : array (Restriction_Id) of Source_Ptr;
  77    --  Locations of Restrictions pragmas for error message purposes.
  78    --  Valid only if corresponding entry in Restrictions is set.
  79
  80    Main_Restrictions : Restrictions_Flags := (others => False);
  81    --  This variable saves the cumulative restrictions in effect compiling
  82    --  any unit that is part of the extended main unit (i.e. the compiled
  83    --  unit, its spec if any, and its subunits if any). The reason we keep
  84    --  track of this is for the information that goes to the binder about
  85    --  restrictions that are set. The binder will identify a unit that has
  86    --  a restrictions pragma for error message purposes, and we do not want
  87    --  to pick up a restrictions pragma in a with'ed unit for this purpose.
  88
  89    Violations : Restrictions_Flags := (others => False);
  90    --  Corresponding entry is False if the restriction has not been
  91    --  violated in the current main unit, and True if it has been violated.
  92
  93    Restriction_Parameters :
  94      array (Restriction_Parameter_Id) of Uint := (others => No_Uint);
  95    --  This array indicates the setting of restriction parameter identifier
  96    --  values. All values are initially set to No_Uint indicating that the
  97    --  parameter is not set, and are set to the appropriate non-negative
  98    --  value if a Restrictions pragma specifies the corresponding
  99    --  restriction parameter identifier with an appropriate value.
 100
 101    Restriction_Parameters_Loc :
 102      array (Restriction_Parameter_Id) of Source_Ptr;
 103    --  Locations of Restrictions pragmas for error message purposes.
 104    --  Valid only if corresponding entry in Restriction_Parameters is
 105    --  set to a value other than No_Uint.
 106
 107    type Unit_Entry is record
 108       Res_Id : Restriction_Id;
 109       Filenm : String (1 .. 8);
 110    end record;
 111
 112    type Unit_Array_Type is array (Positive range <>) of Unit_Entry;
 113
 114    Unit_Array : constant Unit_Array_Type := (
 115      (No_Asynchronous_Control,    "a-astaco"),
 116      (No_Calendar,                "a-calend"),
 117      (No_Calendar,                "calendar"),
 118      (No_Delay,                   "a-calend"),
 119      (No_Delay,                   "calendar"),
 120      (No_Dynamic_Priorities,      "a-dynpri"),
 121      (No_IO,                      "a-direio"),
 122      (No_IO,                      "directio"),
 123      (No_IO,                      "a-sequio"),
 124      (No_IO,                      "sequenio"),
 125      (No_IO,                      "a-ststio"),
 126      (No_IO,                      "a-textio"),
 127      (No_IO,                      "text_io "),
 128      (No_IO,                      "a-witeio"),
 129      (No_Task_Attributes,         "a-tasatt"),
 130      (No_Streams,                 "a-stream"),
 131      (No_Unchecked_Conversion,    "a-unccon"),
 132      (No_Unchecked_Conversion,    "unchconv"),
 133      (No_Unchecked_Deallocation,  "a-uncdea"),
 134      (No_Unchecked_Deallocation,  "unchdeal"));
 135    --  This array defines the mapping between restriction identifiers and
 136    --  predefined language files containing units for which the identifier
 137    --  forbids semantic dependence.
 138
 139    type Save_Compilation_Unit_Restrictions is private;
 140    --  Type used for saving and restoring compilation unit restrictions.
 141    --  See Compilation_Unit_Restrictions_[Save|Restore] subprograms.
 142
 143    -----------------
 144    -- Subprograms --
 145    -----------------
 146
 147    procedure Check_Restricted_Unit (U : Unit_Name_Type; N : Node_Id);
 148    --  Checks if loading of unit U is prohibited by the setting of some
 149    --  restriction (e.g. No_IO restricts the loading of unit Ada.Text_IO).
 150    --  If a restriction exists post error message at the given node.
 151
 152    procedure Check_Restriction (R : Restriction_Id; N : Node_Id);
 153    --  Checks that the given restriction is not set, and if it is set, an
 154    --  appropriate message is posted on the given node. Also records the
 155    --  violation in the violations array. Note that it is mandatory to
 156    --  always use this routine to check if a restriction is violated. Such
 157    --  checks must never be done directly by the caller, since otherwise
 158    --  they are not properly recorded in the violations array.
 159
 160    procedure Check_Restriction
 161      (R : Restriction_Parameter_Id;
 162       N : Node_Id);
 163    --  Checks that the given restriction parameter identifier is not set to
 164    --  zero. If it is set to zero, then the node N is replaced by a node
 165    --  that raises Storage_Error, and a warning is issued.
 166
 167    procedure Check_Restriction
 168      (R : Restriction_Parameter_Id;
 169       V : Uint;
 170       N : Node_Id);
 171    --  Checks that the count in V does not exceed the maximum value of the
 172    --  restriction parameter value corresponding to the given restriction
 173    --  parameter identifier (if it has been set). If the count in V exceeds
 174    --  the maximum, then post an error message on node N.
 175
 176    procedure Check_Elaboration_Code_Allowed (N : Node_Id);
 177    --  Tests to see if elaboration code is allowed by the current restrictions
 178    --  settings. This function is called by Gigi when it needs to define
 179    --  an elaboration routine. If elaboration code is not allowed, an error
 180    --  message is posted on the node given as argument.
 181
 182    function No_Exception_Handlers_Set return Boolean;
 183    --  Test to see if current restrictions settings specify that no exception
 184    --  handlers are present. This function is called by Gigi when it needs to
 185    --  expand an AT END clean up identifier with no exception handler.
 186
 187    function Compilation_Unit_Restrictions_Save
 188      return Save_Compilation_Unit_Restrictions;
 189    --  This function saves the compilation unit restriction settings, and
 190    --  resets them to False. This is used e.g. when compiling a with'ed
 191    --  unit to avoid incorrectly propagating restrictions. Note that it
 192    --  would not be wrong to also save and reset the partition restrictions,
 193    --  since the binder would catch inconsistencies, but actually it is a
 194    --  good thing to acquire restrictions from with'ed units if they are
 195    --  required to be partition wide, because it allows the restriction
 196    --  violation message to be given at compile time instead of link time.
 197
 198    procedure Compilation_Unit_Restrictions_Restore
 199      (R : Save_Compilation_Unit_Restrictions);
 200    --  This is the corresponding restore procedure to restore restrictions
 201    --  previously saved by Compilation_Unit_Restrictions_Save.
 202
 203    procedure Disallow_In_No_Run_Time_Mode (Enode : Node_Id);
 204    --  If in No_Run_Time mode, then the construct represented by Enode is
 205    --  not permitted, and will be appropriately flagged.
 206
 207    procedure Set_No_Run_Time_Mode;
 208    --  Set the no run time mode, and associated restriction pragmas.
 209
 210    function Get_Restriction_Id
 211      (N    : Name_Id)
 212       return Restriction_Id;
 213    --  Given an identifier name, determines if it is a valid restriction
 214    --  identifier, and if so returns the corresponding Restriction_Id
 215    --  value, otherwise returns Not_A_Restriction_Id.
 216
 217    function Get_Restriction_Parameter_Id
 218      (N    : Name_Id)
 219       return Restriction_Parameter_Id;
 220    --  Given an identifier name, determines if it is a valid restriction
 221    --  parameter identifier, and if so returns the corresponding
 222    --  Restriction_Parameter_Id value, otherwise returns
 223    --  Not_A_Restriction_Parameter_Id.
 224
 225    function Abort_Allowed return Boolean;
 226    pragma Inline (Abort_Allowed);
 227    --  Tests to see if abort is allowed by the current restrictions settings.
 228    --  For abort to be allowed, either No_Abort_Statements must be False,
 229    --  or Max_Asynchronous_Select_Nesting must be non-zero.
 230
 231    function Restricted_Profile return Boolean;
 232    --  Tests to see if tasking operations follow the GNAT restricted run time
 233    --  profile.
 234
 235    procedure Set_Ravenscar;
 236    --  Sets the set of rerstrictions fro Ravenscar
 237
 238    procedure Set_Restricted_Profile;
 239    --  Sets the set of restrictions for pragma Restricted_Run_Time
 240
 241    function Tasking_Allowed return Boolean;
 242    pragma Inline (Tasking_Allowed);
 243    --  Tests to see if tasking operations are allowed by the current
 244    --  restrictions settings. For tasking to be allowed Max_Tasks must
 245    --  be non-zero.
 246
 247 private
 248    type Save_Compilation_Unit_Restrictions is
 249      array (Compilation_Unit_Restrictions) of Boolean;
 250    --  Type used for saving and restoring compilation unit restrictions.
 251    --  See Compilation_Unit_Restrictions_[Save|Restore] subprograms.
 252
 253 end Restrict;