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) 1992-2009, 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 defines the set of restriction identifiers. It is a generic
  33 --  package that is instantiated by the compiler/binder in package Rident, and
  34 --  is instantiated in package System.Restrictions for use at run-time.
  35
  36 --  The reason that we make this a generic package is so that in the case of
  37 --  the instantiation in Rident for use at compile time and bind time, we can
  38 --  generate normal image tables for the enumeration types, which are needed
  39 --  for diagnostic and informational messages. At run-time we really do not
  40 --  want to waste the space for these image tables, and they are not needed,
  41 --  so we can do the instantiation under control of Discard_Names to remove
  42 --  the tables.
  43
  44 generic
  45 package System.Rident is
  46    pragma Preelaborate;
  47
  48    --  The following enumeration type defines the set of restriction
  49    --  identifiers that are implemented in GNAT.
  50
  51    --  To add a new restriction identifier, add an entry with the name to be
  52    --  used in the pragma, and add calls to the Restrict.Check_Restriction
  53    --  routine as appropriate.
  54
  55    type Restriction_Id is
  56
  57       --  The following cases are checked for consistency in the binder. The
  58       --  binder will check that every unit either has the restriction set, or
  59       --  does not violate the restriction.
  60
  61      (Simple_Barriers,                         -- GNAT (Ravenscar)
  62       No_Abort_Statements,                     -- (RM D.7(5), H.4(3))
  63       No_Access_Subprograms,                   -- (RM H.4(17))
  64       No_Allocators,                           -- (RM H.4(7))
  65       No_Asynchronous_Control,                 -- (RM D.7(10))
  66       No_Calendar,                             -- GNAT
  67       No_Delay,                                -- (RM H.4(21))
  68       No_Direct_Boolean_Operators,             -- GNAT
  69       No_Dispatch,                             -- (RM H.4(19))
  70       No_Dispatching_Calls,                    -- GNAT
  71       No_Dynamic_Attachment,                   -- GNAT
  72       No_Dynamic_Priorities,                   -- (RM D.9(9))
  73       No_Enumeration_Maps,                     -- GNAT
  74       No_Entry_Calls_In_Elaboration_Code,      -- GNAT
  75       No_Entry_Queue,                          -- GNAT (Ravenscar)
  76       No_Exception_Handlers,                   -- GNAT
  77       No_Exception_Propagation,                -- GNAT
  78       No_Exception_Registration,               -- GNAT
  79       No_Exceptions,                           -- (RM H.4(12))
  80       No_Finalization,                         -- GNAT
  81       No_Fixed_Point,                          -- (RM H.4(15))
  82       No_Floating_Point,                       -- (RM H.4(14))
  83       No_IO,                                   -- (RM H.4(20))
  84       No_Implicit_Conditionals,                -- GNAT
  85       No_Implicit_Dynamic_Code,                -- GNAT
  86       No_Implicit_Heap_Allocations,            -- (RM D.8(8), H.4(3))
  87       No_Implicit_Loops,                       -- GNAT
  88       No_Initialize_Scalars,                   -- GNAT
  89       No_Local_Allocators,                     -- (RM H.4(8))
  90       No_Local_Timing_Events,                  -- (RM D.7(10.2/2))
  91       No_Local_Protected_Objects,              -- GNAT
  92       No_Nested_Finalization,                  -- (RM D.7(4))
  93       No_Protected_Type_Allocators,            -- GNAT
  94       No_Protected_Types,                      -- (RM H.4(5))
  95       No_Recursion,                            -- (RM H.4(22))
  96       No_Reentrancy,                           -- (RM H.4(23))
  97       No_Relative_Delay,                       -- GNAT (Ravenscar)
  98       No_Requeue_Statements,                   -- GNAT
  99       No_Secondary_Stack,                      -- GNAT
 100       No_Select_Statements,                    -- GNAT (Ravenscar)
 101       No_Specific_Termination_Handlers,        -- (RM D.7(10.7/2))
 102       No_Standard_Storage_Pools,               -- GNAT
 103       No_Stream_Optimizations,                 -- GNAT
 104       No_Streams,                              -- GNAT
 105       No_Task_Allocators,                      -- (RM D.7(7))
 106       No_Task_Attributes_Package,              -- GNAT
 107       No_Task_Hierarchy,                       -- (RM D.7(3), H.4(3))
 108       No_Task_Termination,                     -- GNAT (Ravenscar)
 109       No_Tasking,                              -- GNAT
 110       No_Terminate_Alternatives,               -- (RM D.7(6))
 111       No_Unchecked_Access,                     -- (RM H.4(18))
 112       No_Unchecked_Conversion,                 -- (RM H.4(16))
 113       No_Unchecked_Deallocation,               -- (RM H.4(9))
 114       Static_Priorities,                       -- GNAT
 115       Static_Storage_Size,                     -- GNAT
 116
 117       --  The following require consistency checking with special rules. See
 118       --  individual routines in unit Bcheck for details of what is required.
 119
 120       No_Default_Initialization,               -- GNAT
 121
 122       --  The following cases do not require consistency checking
 123
 124       Immediate_Reclamation,                   -- (RM H.4(10))
 125       No_Implementation_Attributes,            -- Ada 2005 AI-257
 126       No_Implementation_Pragmas,               -- Ada 2005 AI-257
 127       No_Implementation_Restrictions,          -- GNAT
 128       No_Elaboration_Code,                     -- GNAT
 129       No_Obsolescent_Features,                 -- Ada 2005 AI-368
 130       No_Wide_Characters,                      -- GNAT
 131
 132       --  The following cases require a parameter value
 133
 134       --  The following entries are fully checked at compile/bind time, which
 135       --  means that the compiler can in general tell the minimum value which
 136       --  could be used with a restrictions pragma. The binder can deduce the
 137       --  appropriate minimum value for the partition by taking the maximum
 138       --  value required by any unit.
 139
 140       Max_Protected_Entries,                   -- (RM D.7(14))
 141       Max_Select_Alternatives,                 -- (RM D.7(12))
 142       Max_Task_Entries,                        -- (RM D.7(13), H.4(3))
 143
 144       --  The following entries are also fully checked at compile/bind time,
 145       --  and the compiler can also at least in some cases tell the minimum
 146       --  value which could be used with a restriction pragma. The difference
 147       --  is that the contributions are additive, so the binder deduces this
 148       --  value by adding the unit contributions.
 149
 150       Max_Tasks,                               -- (RM D.7(19), H.4(3))
 151
 152       --  The following entries are checked at compile time only for zero/
 153       --  nonzero entries. This means that the compiler can tell at compile
 154       --  time if a restriction value of zero is (would be) violated, but that
 155       --  the compiler cannot distinguish between different non-zero values.
 156
 157       Max_Asynchronous_Select_Nesting,         -- (RM D.7(18), H.4(3))
 158       Max_Entry_Queue_Length,                  -- GNAT
 159
 160       --  The remaining entries are not checked at compile/bind time
 161
 162       Max_Storage_At_Blocking,                 -- (RM D.7(17))
 163
 164       Not_A_Restriction_Id);
 165
 166    --  Synonyms permitted for historical purposes of compatibility.
 167    --  Must be coordinated with Restrict.Process_Restriction_Synonym.
 168
 169    Boolean_Entry_Barriers : Restriction_Id renames Simple_Barriers;
 170    Max_Entry_Queue_Depth  : Restriction_Id renames Max_Entry_Queue_Length;
 171    No_Dynamic_Interrupts  : Restriction_Id renames No_Dynamic_Attachment;
 172    No_Requeue             : Restriction_Id renames No_Requeue_Statements;
 173    No_Task_Attributes     : Restriction_Id renames No_Task_Attributes_Package;
 174
 175    subtype All_Restrictions is Restriction_Id range
 176      Simple_Barriers .. Max_Storage_At_Blocking;
 177    --  All restrictions (excluding only Not_A_Restriction_Id)
 178
 179    subtype All_Boolean_Restrictions is Restriction_Id range
 180      Simple_Barriers .. No_Wide_Characters;
 181    --  All restrictions which do not take a parameter
 182
 183    subtype Partition_Boolean_Restrictions is All_Boolean_Restrictions range
 184      Simple_Barriers .. Static_Storage_Size;
 185    --  Boolean restrictions that are checked for partition consistency.
 186    --  Note that all parameter restrictions are checked for partition
 187    --  consistency by default, so this distinction is only needed in the
 188    --  case of Boolean restrictions.
 189
 190    subtype Cunit_Boolean_Restrictions is All_Boolean_Restrictions range
 191      Immediate_Reclamation .. No_Wide_Characters;
 192    --  Boolean restrictions that are not checked for partition consistency
 193    --  and that thus apply only to the current unit. Note that for these
 194    --  restrictions, the compiler does not apply restrictions found in
 195    --  with'ed units, parent specs etc. to the main unit.
 196
 197    subtype All_Parameter_Restrictions is
 198      Restriction_Id range
 199        Max_Protected_Entries .. Max_Storage_At_Blocking;
 200    --  All restrictions that take a parameter
 201
 202    subtype Checked_Parameter_Restrictions is
 203      All_Parameter_Restrictions range
 204        Max_Protected_Entries .. Max_Entry_Queue_Length;
 205    --  These are the parameter restrictions that can be at least partially
 206    --  checked at compile/binder time. Minimally, the compiler can detect
 207    --  violations of a restriction pragma with a value of zero reliably.
 208
 209    subtype Checked_Max_Parameter_Restrictions is
 210      Checked_Parameter_Restrictions range
 211        Max_Protected_Entries .. Max_Task_Entries;
 212    --  Restrictions with parameters that can be checked in some cases by
 213    --  maximizing among statically detected instances where the compiler
 214    --  can determine the count.
 215
 216    subtype Checked_Add_Parameter_Restrictions is
 217      Checked_Parameter_Restrictions range
 218        Max_Tasks .. Max_Tasks;
 219    --  Restrictions with parameters that can be checked in some cases by
 220    --  summing the statically detected instances where the compiler can
 221    --  determine the count.
 222
 223    subtype Checked_Val_Parameter_Restrictions is
 224      Checked_Parameter_Restrictions range
 225        Max_Protected_Entries .. Max_Tasks;
 226    --  Restrictions with parameter where the count is known at least in some
 227    --  cases by the compiler/binder.
 228
 229    subtype Checked_Zero_Parameter_Restrictions is
 230      Checked_Parameter_Restrictions range
 231        Max_Asynchronous_Select_Nesting .. Max_Entry_Queue_Length;
 232    --  Restrictions with parameters where the compiler can detect the use of
 233    --  the feature, and hence violations of a restriction specifying a value
 234    --  of zero, but cannot detect specific values other than zero/nonzero.
 235
 236    subtype Unchecked_Parameter_Restrictions is
 237      All_Parameter_Restrictions range
 238        Max_Storage_At_Blocking .. Max_Storage_At_Blocking;
 239    --  Restrictions with parameters where the compiler cannot ever detect
 240    --  corresponding compile time usage, so the binder and compiler never
 241    --  detect violations of any restriction.
 242
 243    -------------------------------------
 244    -- Restriction Status Declarations --
 245    -------------------------------------
 246
 247    --  The following declarations are used to record the current status or
 248    --  restrictions (for the current unit, or related units, at compile time,
 249    --  and for all units in a partition at bind time or run time).
 250
 251    type Restriction_Flags  is array (All_Restrictions)           of Boolean;
 252    type Restriction_Values is array (All_Parameter_Restrictions) of Natural;
 253    type Parameter_Flags    is array (All_Parameter_Restrictions) of Boolean;
 254
 255    type Restrictions_Info is record
 256       Set : Restriction_Flags;
 257       --  An entry is True in the Set array if a restrictions pragma has been
 258       --  encountered for the given restriction. If the value is True for a
 259       --  parameter restriction, then the corresponding entry in the Value
 260       --  array gives the minimum value encountered for any such restriction.
 261
 262       Value : Restriction_Values;
 263       --  If the entry for a parameter restriction in Set is True (i.e. a
 264       --  restrictions pragma for the restriction has been encountered), then
 265       --  the corresponding entry in the Value array is the minimum value
 266       --  specified by any such restrictions pragma. Note that a restrictions
 267       --  pragma specifying a value greater than Int'Last is simply ignored.
 268
 269       Violated : Restriction_Flags;
 270       --  An entry is True in the violations array if the compiler has detected
 271       --  a violation of the restriction. For a parameter restriction, the
 272       --  Count and Unknown arrays have additional information.
 273
 274       Count : Restriction_Values;
 275       --  If an entry for a parameter restriction is True in Violated, the
 276       --  corresponding entry in the Count array may record additional
 277       --  information. If the actual minimum count is known (by taking
 278       --  maximums, or sums, depending on the restriction), it will be
 279       --  recorded in this array. If not, then the value will remain zero.
 280       --  The value is also zero for a non-violated restriction.
 281
 282       Unknown : Parameter_Flags;
 283       --  If an entry for a parameter restriction is True in Violated, the
 284       --  corresponding entry in the Unknown array may record additional
 285       --  information. If the actual count is not known by the compiler (but
 286       --  is known to be non-zero), then the entry in Unknown will be True.
 287       --  This indicates that the value in Count is not known to be exact,
 288       --  and the actual violation count may be higher.
 289
 290       --  Note: If Violated (K) is True, then either Count (K) > 0 or
 291       --  Unknown (K) = True. It is possible for both these to be set.
 292       --  For example, if Count (K) = 3 and Unknown (K) is True, it means
 293       --  that the actual violation count is at least 3 but might be higher.
 294    end record;
 295
 296    No_Restrictions : constant Restrictions_Info :=
 297      (Set      => (others => False),
 298       Value    => (others => 0),
 299       Violated => (others => False),
 300       Count    => (others => 0),
 301       Unknown  => (others => False));
 302    --  Used to initialize Restrictions_Info variables
 303
 304    ----------------------------------
 305    -- Profile Definitions and Data --
 306    ----------------------------------
 307
 308    type Profile_Name is (No_Profile, Ravenscar, Restricted);
 309    --  Names of recognized profiles. No_Profile is used to indicate that a
 310    --  restriction came from pragma Restrictions[_Warning], as opposed to
 311    --  pragma Profile[_Warning].
 312
 313    subtype Profile_Name_Actual is Profile_Name range Ravenscar .. Restricted;
 314    --  Actual used profile names
 315
 316    type Profile_Data is record
 317       Set : Restriction_Flags;
 318       --  Set to True if given restriction must be set for the profile, and
 319       --  False if it need not be set (False does not mean that it must not be
 320       --  set, just that it need not be set). If the flag is True for a
 321       --  parameter restriction, then the Value array gives the maximum value
 322       --  permitted by the profile.
 323
 324       Value : Restriction_Values;
 325       --  An entry in this array is meaningful only if the corresponding flag
 326       --  in Set is True. In that case, the value in this array is the maximum
 327       --  value of the parameter permitted by the profile.
 328    end record;
 329
 330    Profile_Info : array (Profile_Name_Actual) of Profile_Data :=
 331
 332                      --  Restricted Profile
 333
 334                     (Restricted =>
 335
 336                         --  Restrictions for Restricted profile
 337
 338                        (Set   =>
 339                           (No_Abort_Statements             => True,
 340                            No_Asynchronous_Control         => True,
 341                            No_Dynamic_Attachment           => True,
 342                            No_Dynamic_Priorities           => True,
 343                            No_Entry_Queue                  => True,
 344                            No_Local_Protected_Objects      => True,
 345                            No_Protected_Type_Allocators    => True,
 346                            No_Requeue_Statements           => True,
 347                            No_Task_Allocators              => True,
 348                            No_Task_Attributes_Package      => True,
 349                            No_Task_Hierarchy               => True,
 350                            No_Terminate_Alternatives       => True,
 351                            Max_Asynchronous_Select_Nesting => True,
 352                            Max_Protected_Entries           => True,
 353                            Max_Select_Alternatives         => True,
 354                            Max_Task_Entries                => True,
 355                            others                          => False),
 356
 357                         --  Value settings for Restricted profile
 358
 359                         Value =>
 360                           (Max_Asynchronous_Select_Nesting => 0,
 361                            Max_Protected_Entries           => 1,
 362                            Max_Select_Alternatives         => 0,
 363                            Max_Task_Entries                => 0,
 364                            others                          => 0)),
 365
 366                      --  Ravenscar Profile
 367
 368                      --  Note: the table entries here only represent the
 369                      --  required restriction profile for Ravenscar. The
 370                      --  full Ravenscar profile also requires:
 371
 372                      --    pragma Dispatching_Policy (FIFO_Within_Priorities);
 373                      --    pragma Locking_Policy (Ceiling_Locking);
 374                      --    pragma Detect_Blocking
 375
 376                      Ravenscar  =>
 377
 378                      --  Restrictions for Ravenscar = Restricted profile ..
 379
 380                        (Set   =>
 381                           (No_Abort_Statements             => True,
 382                            No_Asynchronous_Control         => True,
 383                            No_Dynamic_Attachment           => True,
 384                            No_Dynamic_Priorities           => True,
 385                            No_Entry_Queue                  => True,
 386                            No_Local_Protected_Objects      => True,
 387                            No_Protected_Type_Allocators    => True,
 388                            No_Requeue_Statements           => True,
 389                            No_Task_Allocators              => True,
 390                            No_Task_Attributes_Package      => True,
 391                            No_Task_Hierarchy               => True,
 392                            No_Terminate_Alternatives       => True,
 393                            Max_Asynchronous_Select_Nesting => True,
 394                            Max_Protected_Entries           => True,
 395                            Max_Select_Alternatives         => True,
 396                            Max_Task_Entries                => True,
 397
 398                            --  plus these additional restrictions:
 399
 400                            No_Calendar                     => True,
 401                            No_Implicit_Heap_Allocations    => True,
 402                            No_Relative_Delay               => True,
 403                            No_Select_Statements            => True,
 404                            No_Task_Termination             => True,
 405                            Simple_Barriers                 => True,
 406                            others                          => False),
 407
 408                         --  Value settings for Ravenscar (same as Restricted)
 409
 410                         Value =>
 411                           (Max_Asynchronous_Select_Nesting => 0,
 412                            Max_Protected_Entries           => 1,
 413                            Max_Select_Alternatives         => 0,
 414                            Max_Task_Entries                => 0,
 415                            others                          => 0)));
 416
 417 end System.Rident;