gcc/ada/ghost.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                G H O S T                                 --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2014-2023, 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.  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 COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  This package contains routines that deal with the static and runtime
  27 --  semantics of Ghost entities.
  28
  29 with Opt;   use Opt;
  30 with Types; use Types;
  31
  32 package Ghost is
  33
  34    procedure Check_Ghost_Completion
  35      (Prev_Id  : Entity_Id;
  36       Compl_Id : Entity_Id);
  37    --  Verify that the Ghost policy of initial entity Prev_Id is compatible
  38    --  with the Ghost policy of completing entity Compl_Id. Emit an error if
  39    --  this is not the case.
  40
  41    procedure Check_Ghost_Context
  42      (Ghost_Id  : Entity_Id;
  43       Ghost_Ref : Node_Id);
  44    --  Determine whether node Ghost_Ref appears within a Ghost-friendly context
  45    --  where Ghost entity Ghost_Id can safely reside.
  46
  47    procedure Check_Ghost_Context_In_Generic_Association
  48      (Actual : Node_Id;
  49       Formal : Entity_Id);
  50    --  Check that if Actual contains references to ghost entities, generic
  51    --  formal parameter Formal is ghost (SPARK RM 6.9(10)).
  52
  53    procedure Check_Ghost_Formal_Procedure_Or_Package
  54      (N          : Node_Id;
  55       Actual     : Entity_Id;
  56       Formal     : Entity_Id;
  57       Is_Default : Boolean := False);
  58    --  Verify that if generic formal procedure (resp. package) Formal is ghost,
  59    --  then Actual is not Empty and also a ghost procedure (resp. package)
  60    --  (SPARK RM 6.9(13-14)). The error if any is located on N. If
  61    --  Is_Default is False, N and Actual represent the actual parameter in an
  62    --  instantiation. Otherwise, they represent the default subprogram of a
  63    --  formal subprogram declaration.
  64
  65    procedure Check_Ghost_Formal_Variable
  66      (Actual     : Node_Id;
  67       Formal     : Entity_Id;
  68       Is_Default : Boolean := False);
  69    --  Verify that if Formal (either an IN OUT generic formal parameter, or an
  70    --  IN generic formal parameter of access-to-variable type) is ghost, then
  71    --  Actual is a ghost object (SPARK RM 6.9(13-14)). Is_Default is True when
  72    --  Actual is the default expression of the formal object declaration.
  73
  74    procedure Check_Ghost_Overriding
  75      (Subp            : Entity_Id;
  76       Overridden_Subp : Entity_Id);
  77    --  Verify that the Ghost policy of parent subprogram Overridden_Subp is
  78    --  compatible with the Ghost policy of overriding subprogram Subp. Emit
  79    --  an error if this is not the case.
  80
  81    procedure Check_Ghost_Primitive (Prim : Entity_Id; Typ : Entity_Id);
  82    --  Verify that the Ghost policy of primitive operation Prim is the same as
  83    --  the Ghost policy of tagged type Typ. Emit an error if this is not the
  84    --  case.
  85
  86    procedure Check_Ghost_Refinement
  87      (State      : Node_Id;
  88       State_Id   : Entity_Id;
  89       Constit    : Node_Id;
  90       Constit_Id : Entity_Id);
  91    --  Verify that the Ghost policy of constituent Constit_Id is compatible
  92    --  with the Ghost policy of abstract state State_I.
  93
  94    procedure Check_Ghost_Type (Typ : Entity_Id);
  95    --  Verify that Ghost type Typ is neither concurrent, nor effectively
  96    --  volatile.
  97
  98    function Implements_Ghost_Interface (Typ : Entity_Id) return Boolean;
  99    --  Determine whether type Typ implements at least one Ghost interface
 100
 101    procedure Initialize;
 102    --  Initialize internal tables
 103
 104    procedure Install_Ghost_Region (Mode : Ghost_Mode_Type; N : Node_Id);
 105    pragma Inline (Install_Ghost_Region);
 106    --  Install a Ghost region described by mode Mode and ignored region start
 107    --  node N.
 108
 109    function Is_Ghost_Assignment (N : Node_Id) return Boolean;
 110    --  Determine whether arbitrary node N denotes an assignment statement whose
 111    --  target is a Ghost entity.
 112
 113    function Is_Ghost_Declaration (N : Node_Id) return Boolean;
 114    --  Determine whether arbitrary node N denotes a declaration which defines
 115    --  a Ghost entity.
 116
 117    function Is_Ghost_Pragma (N : Node_Id) return Boolean;
 118    --  Determine whether arbitrary node N denotes a pragma which encloses a
 119    --  Ghost entity or is associated with a Ghost entity.
 120
 121    function Is_Ghost_Procedure_Call (N : Node_Id) return Boolean;
 122    --  Determine whether arbitrary node N denotes a procedure call invoking a
 123    --  Ghost procedure.
 124
 125    function Is_Ignored_Ghost_Unit (N : Node_Id) return Boolean;
 126    --  Determine whether compilation unit N is subject to pragma Ghost with
 127    --  policy Ignore.
 128
 129    procedure Lock;
 130    --  Lock internal tables before calling backend
 131
 132    procedure Mark_And_Set_Ghost_Assignment (N : Node_Id);
 133    --  Mark assignment statement N as Ghost when:
 134    --
 135    --    * The left hand side denotes a Ghost entity
 136    --
 137    --  Install the Ghost mode of the assignment statement. This routine starts
 138    --  a Ghost region and must be used with routine Restore_Ghost_Region.
 139
 140    procedure Mark_And_Set_Ghost_Body
 141      (N       : Node_Id;
 142       Spec_Id : Entity_Id);
 143    --  Mark package or subprogram body N as Ghost when:
 144    --
 145    --    * The body is subject to pragma Ghost
 146    --
 147    --    * The body completes a previous declaration whose spec denoted by
 148    --      Spec_Id is a Ghost entity.
 149    --
 150    --    * The body appears within a Ghost region
 151    --
 152    --  Install the Ghost mode of the body. This routine starts a Ghost region
 153    --  and must be used with routine Restore_Ghost_Region.
 154
 155    procedure Mark_And_Set_Ghost_Completion
 156      (N       : Node_Id;
 157       Prev_Id : Entity_Id);
 158    --  Mark completion N of a deferred constant or private type [extension]
 159    --  Ghost when:
 160    --
 161    --    * The entity of the previous declaration denoted by Prev_Id is Ghost
 162    --
 163    --    * The completion appears within a Ghost region
 164    --
 165    --  Install the Ghost mode of the completion. This routine starts a Ghost
 166    --  region and must be used with routine Restore_Ghost_Region.
 167
 168    procedure Mark_And_Set_Ghost_Declaration (N : Node_Id);
 169    --  Mark declaration N as Ghost when:
 170    --
 171    --    * The declaration is subject to pragma Ghost
 172    --
 173    --    * The declaration denotes a child package or subprogram and the parent
 174    --      is a Ghost unit.
 175    --
 176    --    * The declaration appears within a Ghost region
 177    --
 178    --  Install the Ghost mode of the declaration. This routine starts a Ghost
 179    --  region and must be used with routine Restore_Ghost_Region.
 180
 181    procedure Mark_And_Set_Ghost_Instantiation
 182      (N      : Node_Id;
 183       Gen_Id : Entity_Id);
 184    --  Mark instantiation N as Ghost when:
 185    --
 186    --    * The instantiation is subject to pragma Ghost
 187    --
 188    --    * The generic template denoted by Gen_Id is Ghost
 189    --
 190    --    * The instantiation appears within a Ghost region
 191    --
 192    --  Install the Ghost mode of the instantiation. This routine starts a Ghost
 193    --  region and must be used with routine Restore_Ghost_Region.
 194
 195    procedure Mark_And_Set_Ghost_Procedure_Call (N : Node_Id);
 196    --  Mark procedure call N as Ghost when:
 197    --
 198    --    * The procedure being invoked is a Ghost entity
 199    --
 200    --  Install the Ghost mode of the procedure call. This routine starts a
 201    --  Ghost region and must be used with routine Restore_Ghost_Region.
 202
 203    procedure Mark_Ghost_Clause (N : Node_Id);
 204    --  Mark use package, use type, or with clause N as Ghost when:
 205    --
 206    --    * The clause mentions a Ghost entity
 207
 208    procedure Mark_Ghost_Pragma
 209      (N  : Node_Id;
 210       Id : Entity_Id);
 211    --  Mark pragma N as Ghost when:
 212    --
 213    --    * The pragma encloses Ghost entity Id
 214    --
 215    --    * The pragma is associated with Ghost entity Id
 216
 217    procedure Mark_Ghost_Renaming
 218      (N  : Node_Id;
 219       Id : Entity_Id);
 220    --  Mark renaming declaration N as Ghost when:
 221    --
 222    --    * Renamed entity Id denotes a Ghost entity
 223
 224    procedure Remove_Ignored_Ghost_Code;
 225    --  Remove all code marked as ignored Ghost from the trees of all qualifying
 226    --  units (SPARK RM 6.9(4)).
 227    --
 228    --  WARNING: this is a separate front end pass, care should be taken to keep
 229    --  it optimized.
 230
 231    procedure Restore_Ghost_Region (Mode : Ghost_Mode_Type; N : Node_Id);
 232    pragma Inline (Restore_Ghost_Region);
 233    --  Restore a Ghost region to a previous state described by mode Mode and
 234    --  ignored region start node N. This routine must be used in conjunction
 235    --  with the following routines:
 236    --
 237    --    Install_Ghost_Region
 238    --    Mark_And_Set_xxx
 239    --    Set_Ghost_Mode
 240
 241    procedure Set_Ghost_Mode (N : Node_Or_Entity_Id);
 242    --  Install the Ghost mode of arbitrary node N. This routine starts a Ghost
 243    --  region and must be used with routine Restore_Ghost_Region.
 244
 245    procedure Set_Is_Ghost_Entity (Id : Entity_Id);
 246    --  Set the relevant Ghost attributes of entity Id depending on the current
 247    --  Ghost assertion policy in effect.
 248
 249 end Ghost;