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) 1992-2011, 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 pragma Compiler_Unit;
  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 to be
  54    --  used in the pragma, and add calls to the Restrict.Check_Restriction
  55    --  routine as appropriate.
  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_Allocators_After_Elaboration,         -- Ada 2012 (RM D.7(19.1/2))
  68       No_Anonymous_Allocators,                 -- Ada 2012 (RM H.4(8/1))
  69       No_Asynchronous_Control,                 -- (RM D.7(10))
  70       No_Calendar,                             -- GNAT
  71       No_Default_Stream_Attributes,            -- Ada 2012 (RM 13.12.1(4/2))
  72       No_Delay,                                -- (RM H.4(21))
  73       No_Direct_Boolean_Operators,             -- GNAT
  74       No_Dispatch,                             -- (RM H.4(19))
  75       No_Dispatching_Calls,                    -- GNAT
  76       No_Dynamic_Attachment,                   -- GNAT
  77       No_Dynamic_Priorities,                   -- (RM D.9(9))
  78       No_Enumeration_Maps,                     -- GNAT
  79       No_Entry_Calls_In_Elaboration_Code,      -- GNAT
  80       No_Entry_Queue,                          -- GNAT (Ravenscar)
  81       No_Exception_Handlers,                   -- GNAT
  82       No_Exception_Propagation,                -- GNAT
  83       No_Exception_Registration,               -- GNAT
  84       No_Exceptions,                           -- (RM H.4(12))
  85       No_Finalization,                         -- GNAT
  86       No_Fixed_Point,                          -- (RM H.4(15))
  87       No_Floating_Point,                       -- (RM H.4(14))
  88       No_IO,                                   -- (RM H.4(20))
  89       No_Implicit_Conditionals,                -- GNAT
  90       No_Implicit_Dynamic_Code,                -- GNAT
  91       No_Implicit_Heap_Allocations,            -- (RM D.8(8), H.4(3))
  92       No_Implicit_Loops,                       -- GNAT
  93       No_Initialize_Scalars,                   -- GNAT
  94       No_Local_Allocators,                     -- (RM H.4(8))
  95       No_Local_Timing_Events,                  -- (RM D.7(10.2/2))
  96       No_Local_Protected_Objects,              -- GNAT
  97       No_Nested_Finalization,                  -- (RM D.7(4))
  98       No_Protected_Type_Allocators,            -- GNAT
  99       No_Protected_Types,                      -- (RM H.4(5))
 100       No_Recursion,                            -- (RM H.4(22))
 101       No_Reentrancy,                           -- (RM H.4(23))
 102       No_Relative_Delay,                       -- GNAT (Ravenscar)
 103       No_Requeue_Statements,                   -- GNAT
 104       No_Secondary_Stack,                      -- GNAT
 105       No_Select_Statements,                    -- GNAT (Ravenscar)
 106       No_Specific_Termination_Handlers,        -- (RM D.7(10.7/2))
 107       No_Standard_Storage_Pools,               -- GNAT
 108       No_Stream_Optimizations,                 -- GNAT
 109       No_Streams,                              -- GNAT
 110       No_Task_Allocators,                      -- (RM D.7(7))
 111       No_Task_Attributes_Package,              -- GNAT
 112       No_Task_Hierarchy,                       -- (RM D.7(3), H.4(3))
 113       No_Task_Termination,                     -- GNAT (Ravenscar)
 114       No_Tasking,                              -- GNAT
 115       No_Terminate_Alternatives,               -- (RM D.7(6))
 116       No_Unchecked_Access,                     -- (RM H.4(18))
 117       No_Unchecked_Conversion,                 -- (RM H.4(16))
 118       No_Unchecked_Deallocation,               -- (RM H.4(9))
 119       Static_Priorities,                       -- GNAT
 120       Static_Storage_Size,                     -- GNAT
 121
 122       --  The following require consistency checking with special rules. See
 123       --  individual routines in unit Bcheck for details of what is required.
 124
 125       No_Default_Initialization,               -- GNAT
 126
 127       --  The following cases do not require consistency checking
 128
 129       Immediate_Reclamation,                   -- (RM H.4(10))
 130       No_Implementation_Aspect_Specifications, -- Ada 2012 AI-241
 131       No_Implementation_Attributes,            -- Ada 2005 AI-257
 132       No_Implementation_Identifiers,           -- Ada 2012 AI-246
 133       No_Implementation_Pragmas,               -- Ada 2005 AI-257
 134       No_Implementation_Restrictions,          -- GNAT
 135       No_Implementation_Units,                 -- Ada 2012 AI-242
 136       No_Implicit_Aliasing,                    -- GNAT
 137       No_Elaboration_Code,                     -- GNAT
 138       No_Obsolescent_Features,                 -- Ada 2005 AI-368
 139       No_Wide_Characters,                      -- GNAT
 140       SPARK,                                   -- GNAT
 141
 142       --  The following cases require a parameter value
 143
 144       --  The following entries are fully checked at compile/bind time, which
 145       --  means that the compiler can in general tell the minimum value which
 146       --  could be used with a restrictions pragma. The binder can deduce the
 147       --  appropriate minimum value for the partition by taking the maximum
 148       --  value required by any unit.
 149
 150       Max_Protected_Entries,                   -- (RM D.7(14))
 151       Max_Select_Alternatives,                 -- (RM D.7(12))
 152       Max_Task_Entries,                        -- (RM D.7(13), H.4(3))
 153
 154       --  The following entries are also fully checked at compile/bind time,
 155       --  and the compiler can also at least in some cases tell the minimum
 156       --  value which could be used with a restriction pragma. The difference
 157       --  is that the contributions are additive, so the binder deduces this
 158       --  value by adding the unit contributions.
 159
 160       Max_Tasks,                               -- (RM D.7(19), H.4(3))
 161
 162       --  The following entries are checked at compile time only for zero/
 163       --  nonzero entries. This means that the compiler can tell at compile
 164       --  time if a restriction value of zero is (would be) violated, but that
 165       --  the compiler cannot distinguish between different non-zero values.
 166
 167       Max_Asynchronous_Select_Nesting,         -- (RM D.7(18), H.4(3))
 168       Max_Entry_Queue_Length,                  -- GNAT
 169
 170       --  The remaining entries are not checked at compile/bind time
 171
 172       Max_Storage_At_Blocking,                 -- (RM D.7(17))
 173
 174       Not_A_Restriction_Id);
 175
 176    --  Synonyms permitted for historical purposes of compatibility.
 177    --  Must be coordinated with Restrict.Process_Restriction_Synonym.
 178
 179    Boolean_Entry_Barriers : Restriction_Id renames Simple_Barriers;
 180    Max_Entry_Queue_Depth  : Restriction_Id renames Max_Entry_Queue_Length;
 181    No_Dynamic_Interrupts  : Restriction_Id renames No_Dynamic_Attachment;
 182    No_Requeue             : Restriction_Id renames No_Requeue_Statements;
 183    No_Task_Attributes     : Restriction_Id renames No_Task_Attributes_Package;
 184
 185    subtype All_Restrictions is Restriction_Id range
 186      Simple_Barriers .. Max_Storage_At_Blocking;
 187    --  All restrictions (excluding only Not_A_Restriction_Id)
 188
 189    subtype All_Boolean_Restrictions is Restriction_Id range
 190      Simple_Barriers .. SPARK;
 191    --  All restrictions which do not take a parameter
 192
 193    subtype Partition_Boolean_Restrictions is All_Boolean_Restrictions range
 194      Simple_Barriers .. Static_Storage_Size;
 195    --  Boolean restrictions that are checked for partition consistency.
 196    --  Note that all parameter restrictions are checked for partition
 197    --  consistency by default, so this distinction is only needed in the
 198    --  case of Boolean restrictions.
 199
 200    subtype Cunit_Boolean_Restrictions is All_Boolean_Restrictions range
 201      Immediate_Reclamation .. SPARK;
 202    --  Boolean restrictions that are not checked for partition consistency
 203    --  and that thus apply only to the current unit. Note that for these
 204    --  restrictions, the compiler does not apply restrictions found in
 205    --  with'ed units, parent specs etc. to the main unit.
 206
 207    subtype All_Parameter_Restrictions is
 208      Restriction_Id range
 209        Max_Protected_Entries .. Max_Storage_At_Blocking;
 210    --  All restrictions that take a parameter
 211
 212    subtype Checked_Parameter_Restrictions is
 213      All_Parameter_Restrictions range
 214        Max_Protected_Entries .. Max_Entry_Queue_Length;
 215    --  These are the parameter restrictions that can be at least partially
 216    --  checked at compile/binder time. Minimally, the compiler can detect
 217    --  violations of a restriction pragma with a value of zero reliably.
 218
 219    subtype Checked_Max_Parameter_Restrictions is
 220      Checked_Parameter_Restrictions range
 221        Max_Protected_Entries .. Max_Task_Entries;
 222    --  Restrictions with parameters that can be checked in some cases by
 223    --  maximizing among statically detected instances where the compiler
 224    --  can determine the count.
 225
 226    subtype Checked_Add_Parameter_Restrictions is
 227      Checked_Parameter_Restrictions range
 228        Max_Tasks .. Max_Tasks;
 229    --  Restrictions with parameters that can be checked in some cases by
 230    --  summing the statically detected instances where the compiler can
 231    --  determine the count.
 232
 233    subtype Checked_Val_Parameter_Restrictions is
 234      Checked_Parameter_Restrictions range
 235        Max_Protected_Entries .. Max_Tasks;
 236    --  Restrictions with parameter where the count is known at least in some
 237    --  cases by the compiler/binder.
 238
 239    subtype Checked_Zero_Parameter_Restrictions is
 240      Checked_Parameter_Restrictions range
 241        Max_Asynchronous_Select_Nesting .. Max_Entry_Queue_Length;
 242    --  Restrictions with parameters where the compiler can detect the use of
 243    --  the feature, and hence violations of a restriction specifying a value
 244    --  of zero, but cannot detect specific values other than zero/nonzero.
 245
 246    subtype Unchecked_Parameter_Restrictions is
 247      All_Parameter_Restrictions range
 248        Max_Storage_At_Blocking .. Max_Storage_At_Blocking;
 249    --  Restrictions with parameters where the compiler cannot ever detect
 250    --  corresponding compile time usage, so the binder and compiler never
 251    --  detect violations of any restriction.
 252
 253    -------------------------------------
 254    -- Restriction Status Declarations --
 255    -------------------------------------
 256
 257    --  The following declarations are used to record the current status or
 258    --  restrictions (for the current unit, or related units, at compile time,
 259    --  and for all units in a partition at bind time or run time).
 260
 261    type Restriction_Flags  is array (All_Restrictions)           of Boolean;
 262    type Restriction_Values is array (All_Parameter_Restrictions) of Natural;
 263    type Parameter_Flags    is array (All_Parameter_Restrictions) of Boolean;
 264
 265    type Restrictions_Info is record
 266       Set : Restriction_Flags;
 267       --  An entry is True in the Set array if a restrictions pragma has been
 268       --  encountered for the given restriction. If the value is True for a
 269       --  parameter restriction, then the corresponding entry in the Value
 270       --  array gives the minimum value encountered for any such restriction.
 271
 272       Value : Restriction_Values;
 273       --  If the entry for a parameter restriction in Set is True (i.e. a
 274       --  restrictions pragma for the restriction has been encountered), then
 275       --  the corresponding entry in the Value array is the minimum value
 276       --  specified by any such restrictions pragma. Note that a restrictions
 277       --  pragma specifying a value greater than Int'Last is simply ignored.
 278
 279       Violated : Restriction_Flags;
 280       --  An entry is True in the violations array if the compiler has detected
 281       --  a violation of the restriction. For a parameter restriction, the
 282       --  Count and Unknown arrays have additional information.
 283
 284       Count : Restriction_Values;
 285       --  If an entry for a parameter restriction is True in Violated, the
 286       --  corresponding entry in the Count array may record additional
 287       --  information. If the actual minimum count is known (by taking
 288       --  maximums, or sums, depending on the restriction), it will be
 289       --  recorded in this array. If not, then the value will remain zero.
 290       --  The value is also zero for a non-violated restriction.
 291
 292       Unknown : Parameter_Flags;
 293       --  If an entry for a parameter restriction is True in Violated, the
 294       --  corresponding entry in the Unknown array may record additional
 295       --  information. If the actual count is not known by the compiler (but
 296       --  is known to be non-zero), then the entry in Unknown will be True.
 297       --  This indicates that the value in Count is not known to be exact,
 298       --  and the actual violation count may be higher.
 299
 300       --  Note: If Violated (K) is True, then either Count (K) > 0 or
 301       --  Unknown (K) = True. It is possible for both these to be set.
 302       --  For example, if Count (K) = 3 and Unknown (K) is True, it means
 303       --  that the actual violation count is at least 3 but might be higher.
 304    end record;
 305
 306    No_Restrictions : constant Restrictions_Info :=
 307      (Set      => (others => False),
 308       Value    => (others => 0),
 309       Violated => (others => False),
 310       Count    => (others => 0),
 311       Unknown  => (others => False));
 312    --  Used to initialize Restrictions_Info variables
 313
 314    ----------------------------------
 315    -- Profile Definitions and Data --
 316    ----------------------------------
 317
 318    --  Note: to add a profile, modify the following declarations appropriately,
 319    --  add Name_xxx to Snames, and add a branch to the conditions for pragmas
 320    --  Profile and Profile_Warnings in the body of Sem_Prag.
 321
 322    type Profile_Name is
 323      (No_Profile,
 324       No_Implementation_Extensions,
 325       Ravenscar,
 326       Restricted);
 327    --  Names of recognized profiles. No_Profile is used to indicate that a
 328    --  restriction came from pragma Restrictions[_Warning], as opposed to
 329    --  pragma Profile[_Warning].
 330
 331    subtype Profile_Name_Actual is Profile_Name
 332      range No_Implementation_Extensions .. Restricted;
 333    --  Actual used profile names
 334
 335    type Profile_Data is record
 336       Set : Restriction_Flags;
 337       --  Set to True if given restriction must be set for the profile, and
 338       --  False if it need not be set (False does not mean that it must not be
 339       --  set, just that it need not be set). If the flag is True for a
 340       --  parameter restriction, then the Value array gives the maximum value
 341       --  permitted by the profile.
 342
 343       Value : Restriction_Values;
 344       --  An entry in this array is meaningful only if the corresponding flag
 345       --  in Set is True. In that case, the value in this array is the maximum
 346       --  value of the parameter permitted by the profile.
 347    end record;
 348
 349    Profile_Info : constant array (Profile_Name_Actual) of Profile_Data :=
 350
 351                     (No_Implementation_Extensions =>
 352                         --  Restrictions for Restricted profile
 353
 354                        (Set   =>
 355                           (No_Implementation_Aspect_Specifications => True,
 356                            No_Implementation_Attributes            => True,
 357                            No_Implementation_Identifiers           => True,
 358                            No_Implementation_Pragmas               => True,
 359                            No_Implementation_Units                 => True,
 360                            others                                  => False),
 361
 362                         --  Value settings for Restricted profile (none
 363
 364                         Value =>
 365                           (others                          => 0)),
 366
 367                      --  Restricted Profile
 368
 369                      Restricted =>
 370
 371                         --  Restrictions for Restricted profile
 372
 373                        (Set   =>
 374                           (No_Abort_Statements             => True,
 375                            No_Asynchronous_Control         => True,
 376                            No_Dynamic_Attachment           => True,
 377                            No_Dynamic_Priorities           => True,
 378                            No_Entry_Queue                  => True,
 379                            No_Local_Protected_Objects      => True,
 380                            No_Protected_Type_Allocators    => True,
 381                            No_Requeue_Statements           => True,
 382                            No_Task_Allocators              => True,
 383                            No_Task_Attributes_Package      => True,
 384                            No_Task_Hierarchy               => True,
 385                            No_Terminate_Alternatives       => True,
 386                            Max_Asynchronous_Select_Nesting => True,
 387                            Max_Protected_Entries           => True,
 388                            Max_Select_Alternatives         => True,
 389                            Max_Task_Entries                => True,
 390                            others                          => False),
 391
 392                         --  Value settings for Restricted profile
 393
 394                         Value =>
 395                           (Max_Asynchronous_Select_Nesting => 0,
 396                            Max_Protected_Entries           => 1,
 397                            Max_Select_Alternatives         => 0,
 398                            Max_Task_Entries                => 0,
 399                            others                          => 0)),
 400
 401                      --  Ravenscar Profile
 402
 403                      --  Note: the table entries here only represent the
 404                      --  required restriction profile for Ravenscar. The
 405                      --  full Ravenscar profile also requires:
 406
 407                      --    pragma Dispatching_Policy (FIFO_Within_Priorities);
 408                      --    pragma Locking_Policy (Ceiling_Locking);
 409                      --    pragma Detect_Blocking
 410
 411                      Ravenscar  =>
 412
 413                      --  Restrictions for Ravenscar = Restricted profile ..
 414
 415                        (Set   =>
 416                           (No_Abort_Statements             => True,
 417                            No_Asynchronous_Control         => True,
 418                            No_Dynamic_Attachment           => True,
 419                            No_Dynamic_Priorities           => True,
 420                            No_Entry_Queue                  => True,
 421                            No_Local_Protected_Objects      => True,
 422                            No_Protected_Type_Allocators    => True,
 423                            No_Requeue_Statements           => True,
 424                            No_Task_Allocators              => True,
 425                            No_Task_Attributes_Package      => True,
 426                            No_Task_Hierarchy               => True,
 427                            No_Terminate_Alternatives       => True,
 428                            Max_Asynchronous_Select_Nesting => True,
 429                            Max_Protected_Entries           => True,
 430                            Max_Select_Alternatives         => True,
 431                            Max_Task_Entries                => True,
 432
 433                            --  plus these additional restrictions:
 434
 435                            No_Calendar                     => True,
 436                            No_Implicit_Heap_Allocations    => True,
 437                            No_Relative_Delay               => True,
 438                            No_Select_Statements            => True,
 439                            No_Task_Termination             => True,
 440                            Simple_Barriers                 => True,
 441                            others                          => False),
 442
 443                         --  Value settings for Ravenscar (same as Restricted)
 444
 445                         Value =>
 446                           (Max_Asynchronous_Select_Nesting => 0,
 447                            Max_Protected_Entries           => 1,
 448                            Max_Select_Alternatives         => 0,
 449                            Max_Task_Entries                => 0,
 450                            others                          => 0)));
 451
 452 end System.Rident;