gcc/ada/exp_ch7.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              E X P _ C H 7                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- GNAT was originally developed  by the GNAT team at  New York University. --
  24 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  25 --                                                                          --
  26 ------------------------------------------------------------------------------
  27
  28 with Types; use Types;
  29
  30 package Exp_Ch7 is
  31
  32    procedure Expand_N_Package_Body        (N : Node_Id);
  33    procedure Expand_N_Package_Declaration (N : Node_Id);
  34
  35    ------------------------------
  36    --  Finalization Management --
  37    ------------------------------
  38
  39    function In_Finalization_Root (E : Entity_Id) return Boolean;
  40    --  True if current scope is in package System.Finalization_Root. Used
  41    --  to avoid certain expansions that would involve circularity in the
  42    --  Rtsfind mechanism.
  43
  44    procedure Build_Final_List (N : Node_Id; Typ : Entity_Id);
  45    --  Build finalization list for anonymous access types, and for access
  46    --  types that are frozen before their designated types are known to
  47    --  be controlled.
  48
  49    procedure Build_Controlling_Procs (Typ : Entity_Id);
  50    --  Typ is a record, and array type having controlled components.
  51    --  Create the procedures Deep_Initialize, Deep_Adjust and Deep_Finalize
  52    --  that take care of finalization management at run-time.
  53
  54    procedure Build_Late_Proc (Typ : Entity_Id; Nam : Name_Id);
  55    --  Build one controlling procedure when a late body overrides one of
  56    --  the controlling operations.
  57
  58    function Controller_Component (Typ : Entity_Id) return Entity_Id;
  59    --  Returns the entity of the component whose name is 'Name_uController'
  60
  61    function Controlled_Type (T : Entity_Id) return Boolean;
  62    --  True if T potentially needs finalization actions
  63
  64    function Find_Final_List
  65      (E    : Entity_Id;
  66       Ref  : Node_Id := Empty)
  67       return Node_Id;
  68       --  E is an entity representing a controlled object, a controlled type
  69       --  or a scope. If Ref is not empty, it is a reference to a controlled
  70       --  record, the closest Final list is in the controller component of
  71       --  the record containing Ref otherwise this function returns a
  72       --  reference to the final list attached to the closest dynamic scope
  73       --  (that can be E itself) creating this final list if necessary.
  74
  75    function Has_New_Controlled_Component (E : Entity_Id) return Boolean;
  76    --  E is a type entity. Give the same resul as Has_Controlled_Component
  77    --  except for tagged extensions where the result is True only if the
  78    --  latest extension contains a controlled component.
  79
  80    function Make_Attach_Call
  81      (Obj_Ref      : Node_Id;
  82       Flist_Ref    : Node_Id;
  83       With_Attach  : Node_Id)
  84       return         Node_Id;
  85    --  Attach the referenced object to the referenced Final Chain
  86    --  'Flist_Ref' With_Attach is an expression of type Short_Short_Integer
  87    --  which can be either '0' to signify no attachment, '1' for
  88    --  attachement to a simply linked list or '2' for attachement to a
  89    --  doubly linked list.
  90
  91    function Make_Init_Call
  92      (Ref          : Node_Id;
  93       Typ          : Entity_Id;
  94       Flist_Ref    : Node_Id;
  95       With_Attach  : Node_Id)
  96       return         List_Id;
  97    --  Ref is an expression (with no-side effect and is not required to
  98    --  have been previously analyzed) that references the object to be
  99    --  initialized. Typ is the expected type of Ref, which is a controlled
 100    --  type (Is_Controlled) or a type with controlled components
 101    --  (Has_Controlled). 'Dynamic_Case' controls the way the object is
 102    --  attached which is different whether the object is dynamically
 103    --  allocated or not.
 104    --
 105    --  This function will generate the appropriate calls to make
 106    --  sure that the objects referenced by Ref are initialized. The
 107    --  generate code is quite different depending on the fact the type
 108    --  IS_Controlled or HAS_Controlled but this is not the problem of the
 109    --  caller, the details are in the body.
 110
 111    function Make_Adjust_Call
 112      (Ref          : Node_Id;
 113       Typ          : Entity_Id;
 114       Flist_Ref    : Node_Id;
 115       With_Attach  : Node_Id)
 116       return         List_Id;
 117    --  Ref is an expression (with no-side effect and is not required to
 118    --  have been previously analyzed) that references the object to be
 119    --  adjusted. Typ is the expected type of Ref, which is a controlled
 120    --  type (Is_Controlled) or a type with controlled components
 121    --  (Has_Controlled).
 122    --
 123    --  This function will generate the appropriate calls to make
 124    --  sure that the objects referenced by Ref are adjusted. The generated
 125    --  code is quite different depending on the fact the type IS_Controlled
 126    --  or HAS_Controlled but this is not the problem of the caller, the
 127    --  details are in the body. If the parameter With_Attach is set to
 128    --  True, the finalizable objects involved are attached to the proper
 129    --  finalization chain. The objects must be attached when the adjust
 130    --  takes place after an initialization expression but not when it takes
 131    --  place after a regular assignment.
 132    --
 133    --  The description of With_Attach is completely obsolete ???
 134
 135    function Make_Final_Call
 136      (Ref         : Node_Id;
 137       Typ         : Entity_Id;
 138       With_Detach : Node_Id)
 139       return        List_Id;
 140    --  Ref is an expression (with no-side effect and is not required to
 141    --  have been previously analyzed) that references the object
 142    --  to be Finalized. Typ is the expected type of Ref, which is a
 143    --  controlled type (Is_Controlled) or a type with controlled
 144    --  components (Has_Controlled).
 145    --
 146    --  This function will generate the appropriate calls to make
 147    --  sure that the objects referenced by Ref are finalized. The generated
 148    --  code is quite different depending on the fact the type IS_Controlled
 149    --  or HAS_Controlled but this is not the problem of the caller, the
 150    --  details are in the body. If the parameter With_Detach is set to
 151    --  True, the finalizable objects involved are detached from the proper
 152    --  finalization chain. The objects must be detached when finalizing an
 153    --  unchecked deallocated object but not when finalizing the target of
 154    --  an assignment, it is not necessary either on scope exit.
 155
 156    procedure Expand_Ctrl_Function_Call (N : Node_Id);
 157    --  Expand a call to a function returning a controlled value. That is to
 158    --  say attach the result of the call to the current finalization list,
 159    --  which is the one of the transient scope created for such constructs.
 160
 161    --------------------------------
 162    -- Transient Scope Management --
 163    --------------------------------
 164
 165    procedure Expand_Cleanup_Actions (N : Node_Id);
 166    --  Expand the necessary stuff into a scope to enable finalization of local
 167    --  objects and deallocation of transient data when exiting the scope. N is
 168    --  a "scope node" that is to say one of the following: N_Block_Statement,
 169    --  N_Subprogram_Body, N_Task_Body, N_Entry_Body.
 170
 171    procedure Establish_Transient_Scope (N : Node_Id; Sec_Stack : Boolean);
 172    --  Push a new transient scope on the scope stack. N is the node responsible
 173    --  for the need of a transient scope. If Sec_Stack is True then the
 174    --  secondary stack is brought in, otherwise it isn't.
 175
 176    function Node_To_Be_Wrapped return Node_Id;
 177    --  return the node to be wrapped if the current scope is transient.
 178
 179    procedure Store_Before_Actions_In_Scope (L : List_Id);
 180    --  Append the list L of actions to the end of the before-actions store
 181    --  in the top of the scope stack
 182
 183    procedure Store_After_Actions_In_Scope (L : List_Id);
 184    --  Append the list L of actions to the beginning of the after-actions
 185    --  store in the top of the scope stack
 186
 187    procedure Wrap_Transient_Declaration (N : Node_Id);
 188    --  N is an object declaration. Expand the finalization calls after the
 189    --  declaration and make the outer scope beeing the transient one.
 190
 191    procedure Wrap_Transient_Expression (N : Node_Id);
 192    --  N is a sub-expression. Expand a transient block around an expression
 193
 194    procedure Wrap_Transient_Statement (N : Node_Id);
 195    --  N is a statement. Expand a transient block around an instruction
 196
 197 end Exp_Ch7;