gcc/ada/s-rident.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                         S Y S T E M . R I D E N T                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2008, 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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the GNU Public License.                                       --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package defines the set of restriction identifiers. It is a generic
  35 --  package that is instantiated by the compiler/binder in package Rident, and
  36 --  is instantiated in package System.Restrictions for use at run-time.
  37
  38 --  The reason that we make this a generic package is so that in the case of
  39 --  the instantiation in Rident for use at compile time and bind time, we can
  40 --  generate normal image tables for the enumeration types, which are needed
  41 --  for diagnostic and informational messages. At run-time we really do not
  42 --  want to waste the space for these image tables, and they are not needed,
  43 --  so we can do the instantiation under control of Discard_Names to remove
  44 --  the tables.
  45
  46 generic
  47 package System.Rident is
  48    pragma Preelaborate;
  49
  50    --  The following enumeration type defines the set of restriction
  51    --  identifiers that are implemented in GNAT.
  52
  53    --  To add a new restriction identifier, add an entry with the name
  54    --  to be used in the pragma, and add appropriate calls to the
  55    --  Restrict.Check_Restriction routine.
  56
  57    type Restriction_Id is
  58
  59       --  The following cases are checked for consistency in the binder. The
  60       --  binder will check that every unit either has the restriction set, or
  61       --  does not violate the restriction.
  62
  63      (Simple_Barriers,                         -- GNAT (Ravenscar)
  64       No_Abort_Statements,                     -- (RM D.7(5), H.4(3))
  65       No_Access_Subprograms,                   -- (RM H.4(17))
  66       No_Allocators,                           -- (RM H.4(7))
  67       No_Asynchronous_Control,                 -- (RM D.7(10))
  68       No_Calendar,                             -- GNAT
  69       No_Delay,                                -- (RM H.4(21))
  70       No_Direct_Boolean_Operators,             -- GNAT
  71       No_Dispatch,                             -- (RM H.4(19))
  72       No_Dispatching_Calls,                    -- GNAT
  73       No_Dynamic_Attachment,                   -- GNAT
  74       No_Dynamic_Priorities,                   -- (RM D.9(9))
  75       No_Enumeration_Maps,                     -- GNAT
  76       No_Entry_Calls_In_Elaboration_Code,      -- GNAT
  77       No_Entry_Queue,                          -- GNAT (Ravenscar)
  78       No_Exception_Handlers,                   -- GNAT
  79       No_Exception_Propagation,                -- GNAT
  80       No_Exception_Registration,               -- GNAT
  81       No_Exceptions,                           -- (RM H.4(12))
  82       No_Finalization,                         -- GNAT
  83       No_Fixed_Point,                          -- (RM H.4(15))
  84       No_Floating_Point,                       -- (RM H.4(14))
  85       No_IO,                                   -- (RM H.4(20))
  86       No_Implicit_Conditionals,                -- GNAT
  87       No_Implicit_Dynamic_Code,                -- GNAT
  88       No_Implicit_Heap_Allocations,            -- (RM D.8(8), H.4(3))
  89       No_Implicit_Loops,                       -- GNAT
  90       No_Initialize_Scalars,                   -- GNAT
  91       No_Local_Allocators,                     -- (RM H.4(8))
  92       No_Local_Timing_Events,                  -- (RM D.7(10.2/2))
  93       No_Local_Protected_Objects,              -- GNAT
  94       No_Nested_Finalization,                  -- (RM D.7(4))
  95       No_Protected_Type_Allocators,            -- GNAT
  96       No_Protected_Types,                      -- (RM H.4(5))
  97       No_Recursion,                            -- (RM H.4(22))
  98       No_Reentrancy,                           -- (RM H.4(23))
  99       No_Relative_Delay,                       -- GNAT (Ravenscar)
 100       No_Requeue_Statements,                   -- GNAT
 101       No_Secondary_Stack,                      -- GNAT
 102       No_Select_Statements,                    -- GNAT (Ravenscar)
 103       No_Specific_Termination_Handlers,        -- (RM D.7(10.7/2))
 104       No_Standard_Storage_Pools,               -- GNAT
 105       No_Streams,                              -- GNAT
 106       No_Task_Allocators,                      -- (RM D.7(7))
 107       No_Task_Attributes_Package,              -- GNAT
 108       No_Task_Hierarchy,                       -- (RM D.7(3), H.4(3))
 109       No_Task_Termination,                     -- GNAT (Ravenscar)
 110       No_Tasking,                              -- GNAT
 111       No_Terminate_Alternatives,               -- (RM D.7(6))
 112       No_Unchecked_Access,                     -- (RM H.4(18))
 113       No_Unchecked_Conversion,                 -- (RM H.4(16))
 114       No_Unchecked_Deallocation,               -- (RM H.4(9))
 115       Static_Priorities,                       -- GNAT
 116       Static_Storage_Size,                     -- GNAT
 117
 118       --  The following require consistency checking with special rules. See
 119       --  individual routines in unit Bcheck for details of what is required.
 120
 121       No_Default_Initialization,               -- GNAT
 122
 123       --  The following cases do not require consistency checking
 124
 125       Immediate_Reclamation,                   -- (RM H.4(10))
 126       No_Implementation_Attributes,            -- Ada 2005 AI-257
 127       No_Implementation_Pragmas,               -- Ada 2005 AI-257
 128       No_Implementation_Restrictions,          -- GNAT
 129       No_Elaboration_Code,                     -- GNAT
 130       No_Obsolescent_Features,                 -- Ada 2005 AI-368
 131       No_Wide_Characters,                      -- GNAT
 132
 133       --  The following cases require a parameter value
 134
 135       --  The following entries are fully checked at compile/bind time, which
 136       --  means that the compiler can in general tell the minimum value which
 137       --  could be used with a restrictions pragma. The binder can deduce the
 138       --  appropriate minimum value for the partition by taking the maximum
 139       --  value required by any unit.
 140
 141       Max_Protected_Entries,                   -- (RM D.7(14))
 142       Max_Select_Alternatives,                 -- (RM D.7(12))
 143       Max_Task_Entries,                        -- (RM D.7(13), H.4(3))
 144
 145       --  The following entries are also fully checked at compile/bind time,
 146       --  and the compiler can also at least in some cases tell the minimum
 147       --  value which could be used with a restriction pragma. The difference
 148       --  is that the contributions are additive, so the binder deduces this
 149       --  value by adding the unit contributions.
 150
 151       Max_Tasks,                               -- (RM D.7(19), H.4(3))
 152
 153       --  The following entries are checked at compile time only for zero/
 154       --  nonzero entries. This means that the compiler can tell at compile
 155       --  time if a restriction value of zero is (would be) violated, but that
 156       --  the compiler cannot distinguish between different non-zero values.
 157
 158       Max_Asynchronous_Select_Nesting,         -- (RM D.7(18), H.4(3))
 159       Max_Entry_Queue_Length,                  -- GNAT
 160
 161       --  The remaining entries are not checked at compile/bind time
 162
 163       Max_Storage_At_Blocking,                 -- (RM D.7(17))
 164
 165       Not_A_Restriction_Id);
 166
 167    --  Synonyms permitted for historical purposes of compatibility.
 168    --  Must be coordinated with Restrict.Process_Restriction_Synonym.
 169
 170    Boolean_Entry_Barriers : Restriction_Id renames Simple_Barriers;
 171    Max_Entry_Queue_Depth  : Restriction_Id renames Max_Entry_Queue_Length;
 172    No_Dynamic_Interrupts  : Restriction_Id renames No_Dynamic_Attachment;
 173    No_Requeue             : Restriction_Id renames No_Requeue_Statements;
 174    No_Task_Attributes     : Restriction_Id renames No_Task_Attributes_Package;
 175
 176    subtype All_Restrictions is Restriction_Id range
 177      Simple_Barriers .. Max_Storage_At_Blocking;
 178    --  All restrictions (excluding only Not_A_Restriction_Id)
 179
 180    subtype All_Boolean_Restrictions is Restriction_Id range
 181      Simple_Barriers .. No_Wide_Characters;
 182    --  All restrictions which do not take a parameter
 183
 184    subtype Partition_Boolean_Restrictions is All_Boolean_Restrictions range
 185      Simple_Barriers .. Static_Storage_Size;
 186    --  Boolean restrictions that are checked for partition consistency.
 187    --  Note that all parameter restrictions are checked for partition
 188    --  consistency by default, so this distinction is only needed in the
 189    --  case of Boolean restrictions.
 190
 191    subtype Cunit_Boolean_Restrictions is All_Boolean_Restrictions range
 192      Immediate_Reclamation .. No_Wide_Characters;
 193    --  Boolean restrictions that are not checked for partition consistency
 194    --  and that thus apply only to the current unit. Note that for these
 195    --  restrictions, the compiler does not apply restrictions found in
 196    --  with'ed units, parent specs etc. to the main unit.
 197
 198    subtype All_Parameter_Restrictions is
 199      Restriction_Id range
 200        Max_Protected_Entries .. Max_Storage_At_Blocking;
 201    --  All restrictions that are take a parameter
 202
 203    subtype Checked_Parameter_Restrictions is
 204      All_Parameter_Restrictions range
 205        Max_Protected_Entries .. Max_Entry_Queue_Length;
 206    --  These are the parameter restrictions that can be at least partially
 207    --  checked at compile/binder time. Minimally, the compiler can detect
 208    --  violations of a restriction pragma with a value of zero reliably.
 209
 210    subtype Checked_Max_Parameter_Restrictions is
 211      Checked_Parameter_Restrictions range
 212        Max_Protected_Entries .. Max_Task_Entries;
 213    --  Restrictions with parameters that can be checked in some cases by
 214    --  maximizing among statically detected instances where the compiler
 215    --  can determine the count.
 216
 217    subtype Checked_Add_Parameter_Restrictions is
 218      Checked_Parameter_Restrictions range
 219        Max_Tasks .. Max_Tasks;
 220    --  Restrictions with parameters that can be checked in some cases by
 221    --  summing the statically detected instances where the compiler can
 222    --  determine the count.
 223
 224    subtype Checked_Val_Parameter_Restrictions is
 225      Checked_Parameter_Restrictions range
 226        Max_Protected_Entries .. Max_Tasks;
 227    --  Restrictions with parameter where the count is known at least in
 228    --  some cases by the compiler/binder.
 229
 230    subtype Checked_Zero_Parameter_Restrictions is
 231      Checked_Parameter_Restrictions range
 232        Max_Asynchronous_Select_Nesting .. Max_Entry_Queue_Length;
 233    --  Restrictions with parameters where the compiler can detect the use of
 234    --  the feature, and hence violations of a restriction specifying a value
 235    --  of zero, but cannot detect specific values other than zero/nonzero.
 236
 237    subtype Unchecked_Parameter_Restrictions is
 238      All_Parameter_Restrictions range
 239        Max_Storage_At_Blocking .. Max_Storage_At_Blocking;
 240    --  Restrictions with parameters where the compiler cannot ever detect
 241    --  corresponding compile time usage, so the binder and compiler never
 242    --  detect violations of any restriction.
 243
 244    -------------------------------------
 245    -- Restriction Status Declarations --
 246    -------------------------------------
 247
 248    --  The following declarations are used to record the current status or
 249    --  restrictions (for the current unit, or related units, at compile time,
 250    --  and for all units in a partition at bind time or run time).
 251
 252    type Restriction_Flags  is array (All_Restrictions)           of Boolean;
 253    type Restriction_Values is array (All_Parameter_Restrictions) of Natural;
 254    type Parameter_Flags    is array (All_Parameter_Restrictions) of Boolean;
 255
 256    type Restrictions_Info is record
 257       Set : Restriction_Flags;
 258       --  An entry is True in the Set array if a restrictions pragma has been
 259       --  encountered for the given restriction. If the value is True for a
 260       --  parameter restriction, then the corresponding entry in the Value
 261       --  array gives the minimum value encountered for any such restriction.
 262
 263       Value : Restriction_Values;
 264       --  If the entry for a parameter restriction in Set is True (i.e. a
 265       --  restrictions pragma for the restriction has been encountered), then
 266       --  the corresponding entry in the Value array is the minimum value
 267       --  specified by any such restrictions pragma. Note that a restrictions
 268       --  pragma specifying a value greater than Int'Last is simply ignored.
 269
 270       Violated : Restriction_Flags;
 271       --  An entry is True in the violations array if the compiler has detected
 272       --  a violation of the restriction. For a parameter restriction, the
 273       --  Count and Unknown arrays have additional information.
 274
 275       Count : Restriction_Values;
 276       --  If an entry for a parameter restriction is True in Violated, the
 277       --  corresponding entry in the Count array may record additional
 278       --  information. If the actual minimum count is known (by taking
 279       --  maximums, or sums, depending on the restriction), it will be
 280       --  recorded in this array. If not, then the value will remain zero.
 281       --  The value is also zero for a non-violated restriction.
 282
 283       Unknown : Parameter_Flags;
 284       --  If an entry for a parameter restriction is True in Violated, the
 285       --  corresponding entry in the Unknown array may record additional
 286       --  information. If the actual count is not known by the compiler (but
 287       --  is known to be non-zero), then the entry in Unknown will be True.
 288       --  This indicates that the value in Count is not known to be exact,
 289       --  and the actual violation count may be higher.
 290
 291       --  Note: If Violated (K) is True, then either Count (K) > 0 or
 292       --  Unknown (K) = True. It is possible for both these to be set.
 293       --  For example, if Count (K) = 3 and Unknown (K) is True, it means
 294       --  that the actual violation count is at least 3 but might be higher.
 295    end record;
 296
 297    No_Restrictions : constant Restrictions_Info :=
 298      (Set      => (others => False),
 299       Value    => (others => 0),
 300       Violated => (others => False),
 301       Count    => (others => 0),
 302       Unknown  => (others => False));
 303    --  Used to initialize Restrictions_Info variables
 304
 305    ----------------------------------
 306    -- Profile Definitions and Data --
 307    ----------------------------------
 308
 309    type Profile_Name is (Ravenscar, Restricted);
 310    --  Names of recognized profiles
 311
 312    type Profile_Data is record
 313       Set : Restriction_Flags;
 314       --  Set to True if given restriction must be set for the profile,
 315       --  and False if it need not be set (False does not mean that it
 316       --  must not be set, just that it need not be set). If the flag
 317       --  is True for a parameter restriction, then the Value array
 318       --  gives the maximum value permitted by the profile.
 319
 320       Value : Restriction_Values;
 321       --  An entry in this array is meaningful only if the corresponding
 322       --  flag in Set is True. In that case, the value in this array is
 323       --  the maximum value of the parameter permitted by the profile.
 324    end record;
 325
 326    Profile_Info : array (Profile_Name) of Profile_Data :=
 327
 328                      --  Restricted Profile
 329
 330                     (Restricted =>
 331
 332                         --  Restrictions for Restricted profile
 333
 334                        (Set   =>
 335                           (No_Abort_Statements             => True,
 336                            No_Asynchronous_Control         => True,
 337                            No_Dynamic_Attachment           => True,
 338                            No_Dynamic_Priorities           => True,
 339                            No_Entry_Queue                  => True,
 340                            No_Local_Protected_Objects      => True,
 341                            No_Protected_Type_Allocators    => True,
 342                            No_Requeue_Statements           => True,
 343                            No_Task_Allocators              => True,
 344                            No_Task_Attributes_Package      => True,
 345                            No_Task_Hierarchy               => True,
 346                            No_Terminate_Alternatives       => True,
 347                            Max_Asynchronous_Select_Nesting => True,
 348                            Max_Protected_Entries           => True,
 349                            Max_Select_Alternatives         => True,
 350                            Max_Task_Entries                => True,
 351                            others                          => False),
 352
 353                         --  Value settings for Restricted profile
 354
 355                         Value =>
 356                           (Max_Asynchronous_Select_Nesting => 0,
 357                            Max_Protected_Entries           => 1,
 358                            Max_Select_Alternatives         => 0,
 359                            Max_Task_Entries                => 0,
 360                            others                          => 0)),
 361
 362                      --  Ravenscar Profile
 363
 364                      --  Note: the table entries here only represent the
 365                      --  required restriction profile for Ravenscar. The
 366                      --  full Ravenscar profile also requires:
 367
 368                      --    pragma Dispatching_Policy (FIFO_Within_Priorities);
 369                      --    pragma Locking_Policy (Ceiling_Locking);
 370                      --    pragma Detect_Blocking
 371
 372                      Ravenscar  =>
 373
 374                      --  Restrictions for Ravenscar = Restricted profile ..
 375
 376                        (Set   =>
 377                           (No_Abort_Statements             => True,
 378                            No_Asynchronous_Control         => True,
 379                            No_Dynamic_Attachment           => True,
 380                            No_Dynamic_Priorities           => True,
 381                            No_Entry_Queue                  => True,
 382                            No_Local_Protected_Objects      => True,
 383                            No_Protected_Type_Allocators    => True,
 384                            No_Requeue_Statements           => True,
 385                            No_Task_Allocators              => True,
 386                            No_Task_Attributes_Package      => True,
 387                            No_Task_Hierarchy               => True,
 388                            No_Terminate_Alternatives       => True,
 389                            Max_Asynchronous_Select_Nesting => True,
 390                            Max_Protected_Entries           => True,
 391                            Max_Select_Alternatives         => True,
 392                            Max_Task_Entries                => True,
 393
 394                            --  plus these additional restrictions:
 395
 396                            No_Calendar                     => True,
 397                            No_Implicit_Heap_Allocations    => True,
 398                            No_Relative_Delay               => True,
 399                            No_Select_Statements            => True,
 400                            No_Task_Termination             => True,
 401                            Simple_Barriers                 => True,
 402                            others                          => False),
 403
 404                         --  Value settings for Ravenscar (same as Restricted)
 405
 406                         Value =>
 407                           (Max_Asynchronous_Select_Nesting => 0,
 408                            Max_Protected_Entries           => 1,
 409                            Max_Select_Alternatives         => 0,
 410                            Max_Task_Entries                => 0,
 411                            others                          => 0)));
 412
 413 end System.Rident;