gcc/ada/exp_ch9.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              E X P _ C H 9                               --
   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.  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 --  Expand routines for chapter 9 constructs
  27
  28 with Types; use Types;
  29
  30 package Exp_Ch9 is
  31
  32    type Subprogram_Protection_Mode is
  33      (Dispatching_Mode,
  34       Protected_Mode,
  35       Unprotected_Mode);
  36    --  This type is used to distinguish the different protection modes of a
  37    --  protected subprogram.
  38
  39    procedure Build_Activation_Chain_Entity (N : Node_Id);
  40    --  Given a declaration N of an object that is a task, or contains tasks
  41    --  (other than allocators to tasks) this routine ensures that an activation
  42    --  chain has been declared in the appropriate scope, building the required
  43    --  declaration for the chain variable if not. The name of this variable
  44    --  is always _Chain and it is accessed by name.
  45
  46    function Build_Call_With_Task (N : Node_Id; E : Entity_Id) return Node_Id;
  47    --  N is a node representing the name of a task or an access to a task.
  48    --  The value returned is a call to the function whose name is the entity
  49    --  E (typically a runtime routine entity obtained using RTE) with the
  50    --  Task_Id of the associated task as the parameter. The caller is
  51    --  responsible for analyzing and resolving the resulting tree.
  52
  53    function Build_Corresponding_Record
  54      (N    : Node_Id;
  55       Ctyp : Node_Id;
  56       Loc  : Source_Ptr) return Node_Id;
  57    --  Common to tasks and protected types. Copy discriminant specifications,
  58    --  build record declaration. N is the type declaration, Ctyp is the
  59    --  concurrent entity (task type or protected type).
  60
  61    function Build_Entry_Names (Conc_Typ : Entity_Id) return Node_Id;
  62    --  Create the statements which populate the entry names array of a task or
  63    --  protected type. The statements are wrapped inside a block due to a local
  64    --  declaration.
  65
  66    procedure Build_Master_Entity (E : Entity_Id);
  67    --  Given an entity E for the declaration of an object containing tasks
  68    --  or of a type declaration for an allocator whose designated type is a
  69    --  task or contains tasks, this routine marks the appropriate enclosing
  70    --  context as a master, and also declares a variable called _Master in
  71    --  the current declarative part which captures the value of Current_Master
  72    --  (if not already built by a prior call). We build this object (instead
  73    --  of just calling Current_Master) for two reasons. First it is clearly
  74    --  more efficient to call Current_Master only once for a bunch of tasks
  75    --  in the same declarative part, and second it makes things easier in
  76    --  generating the initialization routines, since they can just reference
  77    --  the object _Master by name, and they will get the proper Current_Master
  78    --  value at the outer level, and copy in the parameter value for the outer
  79    --  initialization call if the call is for a nested component). Note that
  80    --  in the case of nested packages, we only really need to make one such
  81    --  object at the outer level, but it is much easier to generate one per
  82    --  declarative part.
  83
  84    function Build_Private_Protected_Declaration (N : Node_Id) return Entity_Id;
  85    --  A subprogram body without a previous spec that appears in a protected
  86    --  body must be expanded separately to create a subprogram declaration
  87    --  for it, in order to resolve internal calls to it from other protected
  88    --  operations. It would seem that no locking version of the operation is
  89    --  needed, but in fact, in Ada 2005 the subprogram may be used in a call-
  90    --  back, and therefore a protected version of the operation must be
  91    --  generated as well.
  92
  93    function Build_Protected_Sub_Specification
  94      (N        : Node_Id;
  95       Prot_Typ : Entity_Id;
  96       Mode     : Subprogram_Protection_Mode) return Node_Id;
  97    --  Build the specification for protected subprogram. This is called when
  98    --  expanding a protected type, and also when expanding the declaration for
  99    --  an Access_To_Protected_Subprogram type. In the latter case, Prot_Typ is
 100    --  empty, and the first parameter of the signature of the protected op is
 101    --  of type System.Address.
 102
 103    procedure Build_Protected_Subprogram_Call
 104      (N        : Node_Id;
 105       Name     : Node_Id;
 106       Rec      : Node_Id;
 107       External : Boolean := True);
 108    --  The node N is a subprogram or entry call to a protected subprogram. This
 109    --  procedure rewrites this call with the appropriate expansion. Name is the
 110    --  subprogram, and Rec is the record corresponding to the protected object.
 111    --  External is False if the call is to another protected subprogram within
 112    --  the same object.
 113
 114    procedure Build_Task_Activation_Call (N : Node_Id);
 115    --  This procedure is called for constructs that can be task activators,
 116    --  i.e. task bodies, subprogram bodies, package bodies and blocks. If the
 117    --  construct is a task activator (as indicated by the non-empty setting of
 118    --  Activation_Chain_Entity, either in the construct, or, in the case of a
 119    --  package body, in its associated package spec), then a call to
 120    --  Activate_Tasks with this entity as the single parameter is inserted at
 121    --  the start of the statements of the activator.
 122
 123    procedure Build_Task_Allocate_Block
 124      (Actions : List_Id;
 125       N       : Node_Id;
 126       Args    : List_Id);
 127    --  This routine is used in the case of allocators where the designated type
 128    --  is a task or contains tasks. In this case, the normal initialize call
 129    --  is replaced by:
 130    --
 131    --    blockname : label;
 132    --    blockname : declare
 133    --       _Chain  : Activation_Chain;
 134    --
 135    --       procedure _Expunge is
 136    --       begin
 137    --         Expunge_Unactivated_Tasks (_Chain);
 138    --       end;
 139    --
 140    --    begin
 141    --       Init (Args);
 142    --       Activate_Tasks (_Chain);
 143    --    at end
 144    --       _Expunge;
 145    --    end;
 146    --
 147    --  to get the task or tasks created and initialized. The expunge call
 148    --  ensures that any tasks that get created but not activated due to an
 149    --  exception are properly expunged (it has no effect in the normal case).
 150    --  The argument N is the allocator, and Args is the list of arguments for
 151    --  the initialization call, constructed by the caller, which uses the
 152    --  Master_Id of the access type as the _Master parameter, and _Chain
 153    --  (defined above) as the _Chain parameter.
 154
 155    procedure Build_Task_Allocate_Block_With_Init_Stmts
 156      (Actions    : List_Id;
 157       N          : Node_Id;
 158       Init_Stmts : List_Id);
 159    --  Ada 2005 (AI-287): Similar to previous routine, but used to expand
 160    --  allocated aggregates with default initialized components. Init_Stmts
 161    --  contains the list of statements required to initialize the allocated
 162    --  aggregate. It replaces the call to Init (Args) done by
 163    --  Build_Task_Allocate_Block.
 164
 165    function Build_Wrapper_Spec
 166      (Subp_Id : Entity_Id;
 167       Obj_Typ : Entity_Id;
 168       Formals : List_Id) return Node_Id;
 169    --  Ada 2005 (AI-345): Build the specification of a primitive operation
 170    --  associated with a protected or task type. This is required to implement
 171    --  dispatching calls through interfaces. Subp_Id is the primitive to be
 172    --  wrapped, Obj_Typ is the type of the newly added formal parameter to
 173    --  handle object notation, Formals are the original entry formals that
 174    --  will be explicitly replicated.
 175
 176    function Concurrent_Ref (N : Node_Id) return Node_Id;
 177    --  Given the name of a concurrent object (task or protected object), or
 178    --  the name of an access to a concurrent object, this function returns an
 179    --  expression referencing the associated Task_Id or Protection object,
 180    --  respectively. Note that a special case is when the name is a reference
 181    --  to a task type name. This can only happen within a task body, and the
 182    --  meaning is to get the Task_Id for the currently executing task.
 183
 184    function Convert_Concurrent
 185      (N   : Node_Id;
 186       Typ : Entity_Id) return Node_Id;
 187    --  N is an expression of type Typ. If the type is not a concurrent type
 188    --  then it is returned unchanged. If it is a task or protected reference,
 189    --  Convert_Concurrent creates an unchecked conversion node from this
 190    --  expression to the corresponding concurrent record type value. We need
 191    --  this in any situation where the concurrent type is used, because the
 192    --  actual concurrent object is an object of the corresponding concurrent
 193    --  type, and manipulations on the concurrent object actually manipulate the
 194    --  corresponding object of the record type.
 195
 196    function Entry_Index_Expression
 197      (Sloc  : Source_Ptr;
 198       Ent   : Entity_Id;
 199       Index : Node_Id;
 200       Ttyp  : Entity_Id)
 201       return  Node_Id;
 202    --  Returns an expression to compute a task entry index given the name of
 203    --  the entry or entry family. For the case of a task entry family, the
 204    --  Index parameter contains the expression for the subscript. Ttyp is the
 205    --  task type.
 206
 207    procedure Establish_Task_Master (N : Node_Id);
 208    --  Given a subprogram body, or a block statement, or a task body, this
 209    --  procedure makes the necessary transformations required of a task master
 210    --  (add Enter_Master call at start, and establish a cleanup routine to make
 211    --  sure Complete_Master is called on exit).
 212
 213    procedure Expand_Access_Protected_Subprogram_Type (N : Node_Id);
 214    --  Build Equivalent_Type for an Access_To_Protected_Subprogram.
 215    --  Equivalent_Type is a record type with two components: a pointer to the
 216    --  protected object, and a pointer to the operation itself.
 217
 218    procedure Expand_Accept_Declarations (N : Node_Id; Ent : Entity_Id);
 219    --  Expand declarations required for accept statement. See bodies of both
 220    --  Expand_Accept_Declarations and Expand_N_Accept_Statement for full
 221    --  details of the nature and use of these declarations, which are inserted
 222    --  immediately before the accept node N. The second argument is the entity
 223    --  for the corresponding entry.
 224
 225    procedure Expand_Entry_Barrier (N : Node_Id; Ent : Entity_Id);
 226    --  Expand the entry barrier into a function. This is called directly
 227    --  from Analyze_Entry_Body so that the discriminals and privals of the
 228    --  barrier can be attached to the function declaration list, and a new
 229    --  set prepared for the entry body procedure, before the entry body
 230    --  statement sequence can be expanded. The resulting function is analyzed
 231    --  now, within the context of the protected object, to resolve calls to
 232    --  other protected functions.
 233
 234    procedure Expand_N_Abort_Statement            (N : Node_Id);
 235    procedure Expand_N_Accept_Statement           (N : Node_Id);
 236    procedure Expand_N_Asynchronous_Select        (N : Node_Id);
 237    procedure Expand_N_Conditional_Entry_Call     (N : Node_Id);
 238    procedure Expand_N_Delay_Relative_Statement   (N : Node_Id);
 239    procedure Expand_N_Delay_Until_Statement      (N : Node_Id);
 240    procedure Expand_N_Entry_Body                 (N : Node_Id);
 241    procedure Expand_N_Entry_Call_Statement       (N : Node_Id);
 242    procedure Expand_N_Entry_Declaration          (N : Node_Id);
 243    procedure Expand_N_Protected_Body             (N : Node_Id);
 244
 245    procedure Expand_N_Protected_Type_Declaration (N : Node_Id);
 246    --  Expands protected type declarations. This results, among other things,
 247    --  in the declaration of a record type for the representation of protected
 248    --  objects and (if there are entries) in an entry service procedure. The
 249    --  Protection value used by the GNARL to control the object will always be
 250    --  the first field of the record, and the entry service procedure spec (if
 251    --  it exists) will always immediately follow the record declaration. This
 252    --  allows these two nodes to be found from the type, without benefit of
 253    --  further attributes, using Corresponding_Record.
 254
 255    procedure Expand_N_Requeue_Statement          (N : Node_Id);
 256    procedure Expand_N_Selective_Accept           (N : Node_Id);
 257    procedure Expand_N_Single_Task_Declaration    (N : Node_Id);
 258    procedure Expand_N_Task_Body                  (N : Node_Id);
 259    procedure Expand_N_Task_Type_Declaration      (N : Node_Id);
 260    procedure Expand_N_Timed_Entry_Call           (N : Node_Id);
 261
 262    procedure Expand_Protected_Body_Declarations
 263      (N       : Node_Id;
 264       Spec_Id : Entity_Id);
 265    --  Expand declarations required for a protected body. See bodies of both
 266    --  Expand_Protected_Body_Declarations and Expand_N_Protected_Body for full
 267    --  details of the nature and use of these declarations. The second argument
 268    --  is the entity for the corresponding protected type declaration.
 269
 270    function External_Subprogram (E : Entity_Id) return Entity_Id;
 271    --  return the external version of a protected operation, which locks
 272    --  the object before invoking the internal protected subprogram body.
 273
 274    function First_Protected_Operation (D : List_Id) return Node_Id;
 275    --  Given the declarations list for a protected body, find the
 276    --  first protected operation body.
 277
 278    procedure Install_Private_Data_Declarations
 279      (Loc      : Source_Ptr;
 280       Spec_Id  : Entity_Id;
 281       Conc_Typ : Entity_Id;
 282       Body_Nod : Node_Id;
 283       Decls    : List_Id;
 284       Barrier  : Boolean := False;
 285       Family   : Boolean := False);
 286    --  This routines generates several types, objects and object renamings used
 287    --  in the handling of discriminants and private components of protected and
 288    --  task types. It also generates the entry index for entry families. Formal
 289    --  Spec_Id denotes an entry, entry family or a subprogram, Conc_Typ is the
 290    --  concurrent type where Spec_Id resides, Body_Nod is the corresponding
 291    --  body of Spec_Id, Decls are the declarations of the subprogram or entry.
 292    --  Flag Barrier denotes whether the context is an entry barrier function.
 293    --  Flag Family is used in conjunction with Barrier to denote a barrier for
 294    --  an entry family.
 295    --
 296    --  The generated types, entities and renamings are:
 297    --
 298    --  * If flag Barrier is set or Spec_Id denotes a protected entry or an
 299    --    entry family, generate:
 300    --
 301    --      type prot_typVP is access prot_typV;
 302    --      _object : prot_typVP := prot_typV (_O);
 303    --
 304    --    where prot_typV is the corresponding record of a protected type and
 305    --    _O is a formal parameter representing the concurrent object of either
 306    --    the barrier function or the entry (family).
 307    --
 308    --  * If Conc_Typ is a protected type, create a renaming for the Protection
 309    --    field _object:
 310    --
 311    --      conc_typR : protection_typ renames _object._object;
 312    --
 313    --  * If Conc_Typ has discriminants, create renamings of the form:
 314    --
 315    --      discr_nameD : discr_typ renames _object.discr_name;
 316    --        or
 317    --      discr_nameD : discr_typ renames _task.discr_name;
 318    --
 319    --  * If Conc_Typ denotes a protected type and has private components,
 320    --    generate renamings of the form:
 321    --
 322    --      comp_name : comp_typ renames _object.comp_name;
 323    --
 324    --  * Finally, is flag Barrier and Family are set or Spec_Id denotes an
 325    --    entry family, generate the entry index constant:
 326    --
 327    --      subtype Jnn is <Type of Index> range Low .. High;
 328    --      J : constant Jnn :=
 329    --            Jnn'Val (_E - <Index expression> + Jnn'Pos (Jnn'First));
 330    --
 331    --  All the above declarations are inserted in the order shown to the front
 332    --  of Decls.
 333
 334    function Make_Task_Create_Call (Task_Rec : Entity_Id) return Node_Id;
 335    --  Given the entity of the record type created for a task type, build
 336    --  the call to Create_Task
 337
 338    function Make_Initialize_Protection
 339      (Protect_Rec : Entity_Id) return List_Id;
 340    --  Given the entity of the record type created for a protected type, build
 341    --  a list of statements needed for proper initialization of the object.
 342
 343    function Next_Protected_Operation (N : Node_Id) return Node_Id;
 344    --  Given a protected operation node (a subprogram or entry body), find the
 345    --  following node in the declarations list.
 346
 347    procedure Set_Discriminals (Dec : Node_Id);
 348    --  Replace discriminals in a protected type for use by the next protected
 349    --  operation on the type. Each operation needs a new set of discriminals,
 350    --  since it needs a unique renaming of the discriminant fields in the
 351    --  record used to implement the protected type.
 352
 353 end Exp_Ch9;