gcc/ada/exp_ch3.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              E X P _ C H 3                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2024, 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 3 constructs
  27
  28 with Elists;  use Elists;
  29 with Exp_Tss; use Exp_Tss;
  30 with Types;   use Types;
  31 with Uintp;   use Uintp;
  32
  33 package Exp_Ch3 is
  34
  35    procedure Expand_N_Object_Declaration         (N : Node_Id);
  36    procedure Expand_N_Subtype_Indication         (N : Node_Id);
  37    procedure Expand_N_Variant_Part               (N : Node_Id);
  38    procedure Expand_N_Full_Type_Declaration      (N : Node_Id);
  39
  40    procedure Expand_Previous_Access_Type (Def_Id : Entity_Id);
  41    --  For a full type declaration that contains tasks, or that is a task,
  42    --  check whether there exists an access type whose designated type is an
  43    --  incomplete declarations for the current composite type. If so, build the
  44    --  master for that access type, now that it is known to denote an object
  45    --  with tasks.
  46
  47    procedure Expand_Record_Extension (T : Entity_Id; Def : Node_Id);
  48    --  Add a field _parent in the extension part of the record
  49
  50    procedure Build_Access_Subprogram_Wrapper_Body
  51      (Decl     : Node_Id;
  52       New_Decl : Node_Id);
  53    --  Build the wrapper body, which holds the indirect call through an access-
  54    --  to-subprogram, and whose expansion incorporates the contracts of the
  55    --  access type declaration. Called from Build_Access_Subprogram_Wrapper.
  56    --  Building the wrapper is done during analysis to perform proper semantic
  57    --  checks on the relevant aspects. The wrapper body could be simplified to
  58    --  a null body when expansion is disabled ???
  59
  60    function Build_Default_Initialization
  61      (N          : Node_Id;
  62       Typ        : Entity_Id;
  63       Obj_Id     : Entity_Id;
  64       For_CW     : Boolean := False;
  65       Target_Ref : Node_Id := Empty) return List_Id;
  66    --  Build the code to default-initialize an object of Typ either declared
  67    --  or allocated by node N if this is necessary. In the former case Obj_Id
  68    --  is the entity for the object whereas, in the second case, Obj_Id is a
  69    --  temporary generated to hold the result of the allocator. For_CW is set
  70    --  to True in the second case if this result is of a class-wide type.
  71
  72    --  Target_Ref is only passed identically to Build_Initialization_Call, so
  73    --  its description given for Build_Initialization_Call is also valid here.
  74
  75    function Build_Default_Simple_Initialization
  76      (N      : Node_Id;
  77       Typ    : Entity_Id;
  78       Obj_Id : Entity_Id) return Node_Id;
  79    --  Try to build an expression to default-initialize an object of Typ either
  80    --  declared or allocated by node N if this is necessary. In the former case
  81    --  Obj_Id is the entity for the object whereas, in the second case, it must
  82    --  be set to Empty.
  83
  84    procedure Build_Or_Copy_Discr_Checking_Funcs (N : Node_Id);
  85    --  For each variant component, builds a function that checks whether
  86    --  the component name is consistent with the current discriminants
  87    --  and sets the component's Dcheck_Function attribute to refer to it.
  88    --  N is the full type declaration node; the discriminant checking
  89    --  functions are inserted after this node.
  90    --  In the case of a derived untagged type, copy the attributes that were
  91    --  set for the components of the parent type onto the components of the
  92    --  derived type; no new subprograms are constructed in this case.
  93
  94    function Build_Initialization_Call
  95      (N                   : Node_Id;
  96       Id_Ref              : Node_Id;
  97       Typ                 : Entity_Id;
  98       In_Init_Proc        : Boolean   := False;
  99       Enclos_Type         : Entity_Id := Empty;
 100       Target_Ref          : Node_Id   := Empty;
 101       Discr_Map           : Elist_Id  := New_Elmt_List;
 102       With_Default_Init   : Boolean   := False;
 103       Constructor_Ref     : Node_Id   := Empty;
 104       Init_Control_Actual : Entity_Id := Empty) return List_Id;
 105    --  Builds a call to the initialization procedure for the base type of Typ,
 106    --  passing it the object denoted by Id_Ref, plus additional parameters as
 107    --  appropriate for the type (the _Master, for task types, for example).
 108    --  N is the construct for which the call is to be built. In_Init_Proc has
 109    --  to be set to True when the call is itself in an init proc in order to
 110    --  enable the use of discriminals.
 111    --
 112    --  Enclos_Type is the enclosing type when initializing a component of a
 113    --  composite type, and is used for the case where Typ is a task type of
 114    --  an array component: the indices of this enclosing type are then used
 115    --  to build the image string that identifies each task at run time.
 116    --
 117    --  Target_Ref is also used when Typ is a task type if the initialization
 118    --  call is to be generated for an allocator. It is either the name of a
 119    --  simple assignment whose expression is the allocator, or the defining
 120    --  identifier of an object declaration whose initializing expression is
 121    --  the allocator, or else the allocator's access type. It is used both
 122    --  to build the image string and to pass the task master.
 123    --
 124    --  Discr_Map is used to replace discriminants by their discriminals in
 125    --  expressions used to constrain record components. In the presence of
 126    --  entry families bounded by discriminants, protected type discriminants
 127    --  can appear within expressions in array bounds (not as stand-alone
 128    --  identifiers) and a general replacement is necessary.
 129    --
 130    --  Ada 2005 (AI-287): With_Default_Init is used to indicate that the
 131    --  initialization call corresponds to a default initialized component
 132    --  of an aggregate.
 133    --
 134    --  Constructor_Ref is a call to a constructor subprogram. It is currently
 135    --  used only to support C++ constructors.
 136    --
 137    --  Init_Control_Actual is Empty except in the case where the init proc
 138    --  for a tagged type calls the init proc for its parent type in order
 139    --  to initialize its _Parent component. In that case, it is the
 140    --  actual parameter value corresponding to the Init_Control formal
 141    --  parameter to be used in the call of the parent type's init proc.
 142
 143    function Build_Variant_Record_Equality
 144      (Typ         : Entity_Id;
 145       Spec_Id     : Entity_Id;
 146       Body_Id     : Entity_Id;
 147       Param_Specs : List_Id) return Node_Id;
 148    --  Build the body of the equality function Body_Id for the untagged variant
 149    --  record Typ with the given parameters specification list. If Spec_Id is
 150    --  present, the body is built for a renaming of the equality function.
 151
 152    function Freeze_Type (N : Node_Id) return Boolean;
 153    --  This function executes the freezing actions associated with the given
 154    --  freeze type node N and returns True if the node is to be deleted. We
 155    --  delete the node if it is present just for front end purpose and we don't
 156    --  want Gigi to see the node. This function can't delete the node itself
 157    --  since it would confuse any remaining processing of the freeze node.
 158    --
 159    --  Note: for GNATprove we have a minimal variant of this routine in
 160    --  Exp_SPARK.SPARK_Freeze_Type. They need to be kept in sync.
 161
 162    function Get_Simple_Init_Val
 163      (Typ  : Entity_Id;
 164       N    : Node_Id;
 165       Size : Uint := No_Uint) return Node_Id;
 166    --  Build an expression that represents the required initial value of type
 167    --  Typ for which predicate Needs_Simple_Initialization is True. N is a node
 168    --  whose source location is used in the construction of the expression.
 169    --  Size is used as follows:
 170    --
 171    --    * If the size of the object to be initialized it is known, it should
 172    --      be passed to the routine.
 173    --
 174    --    * If the size is unknown or is zero, then the Esize of Typ is used as
 175    --      an estimate of the size.
 176    --
 177    --  The object size is needed to prepare a known invalid value for use by
 178    --  Normalize_Scalars. A call to this routine where Typ denotes a scalar
 179    --  type is valid only when Normalize_Scalars or Initialize_Scalars is
 180    --  active, or if N is the node for a 'Invalid_Value attribute node.
 181
 182    procedure Init_Secondary_Tags
 183      (Typ            : Entity_Id;
 184       Target         : Node_Id;
 185       Init_Tags_List : List_Id;
 186       Stmts_List     : List_Id;
 187       Fixed_Comps    : Boolean := True;
 188       Variable_Comps : Boolean := True);
 189    --  Ada 2005 (AI-251): Initialize the tags of the secondary dispatch tables
 190    --  of Typ. The generated code referencing tag fields of Target is appended
 191    --  to Init_Tags_List and the code required to complete the elaboration of
 192    --  the dispatch tables of Typ is appended to Stmts_List. If Fixed_Comps is
 193    --  True then the tag components located at fixed positions of Target are
 194    --  initialized; if Variable_Comps is True then tags components located at
 195    --  variable positions of Target are initialized.
 196
 197    procedure Make_Controlling_Function_Wrappers
 198      (Tag_Typ   : Entity_Id;
 199       Decl_List : out List_Id;
 200       Body_List : out List_Id);
 201    --  Ada 2005 (AI-391): Makes specs and bodies for the wrapper functions
 202    --  associated with inherited functions with controlling results which
 203    --  are not overridden. The body of each wrapper function consists solely
 204    --  of a return statement whose expression is an extension aggregate
 205    --  invoking the inherited subprogram's parent subprogram and extended
 206    --  with a null association list.
 207
 208    procedure Make_Predefined_Primitive_Eq_Spec
 209      (Tag_Typ     : Entity_Id;
 210       Predef_List : List_Id;
 211       Renamed_Eq  : out Entity_Id);
 212    --  Creates spec for the predefined equality on a tagged type Tag_Typ, if
 213    --  required. If created, it will be appended to Predef_List.
 214    --
 215    --  The Parameter Renamed_Eq either returns the value Empty, or else
 216    --  the defining unit name for the predefined equality function in the
 217    --  case where the type has a primitive operation that is a renaming
 218    --  of predefined equality (but only if there is also an overriding
 219    --  user-defined equality function). The returned Renamed_Eq will be
 220    --  passed to the corresponding parameter of Predefined_Primitive_Bodies.
 221
 222    function Make_Tag_Assignment (N : Node_Id) return Node_Id;
 223    --  An object declaration that has an initialization for a tagged object
 224    --  requires a separate reassignment of the tag of the given type, because
 225    --  the expression may include an unchecked conversion. This tag assignment
 226    --  is inserted after the declaration, but if the object has an address
 227    --  clause the assignment is handled as part of the freezing of the object,
 228    --  see Check_Address_Clause.
 229
 230    procedure Predefined_Primitive_Eq_Body
 231      (Tag_Typ     : Entity_Id;
 232       Predef_List : List_Id;
 233       Renamed_Eq  : Entity_Id);
 234    --  Creates body for the predefined equality (and ineqality, if required) on
 235    --  a tagged type Tag_Typ. If created they will be appended to Predef_List.
 236    --
 237    --  The spec for the equality function has been created by
 238    --  Make_Predefined_Primitive_Eq_Spec; see there for description of
 239    --  the Renamed_Eq parameter.
 240
 241    function Stream_Operation_OK
 242      (Typ       : Entity_Id;
 243       Operation : TSS_Name_Type) return Boolean;
 244    --  Check whether the named stream operation must be emitted for a given
 245    --  type. The rules for inheritance of stream attributes by type extensions
 246    --  are enforced by this function. Furthermore, various restrictions prevent
 247    --  the generation of these operations, as a useful optimization or for
 248    --  certification purposes and to save unnecessary generated code.
 249
 250 end Exp_Ch3;