gcc/ada/exp_intr.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             E X P _ I N T R                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2008, 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 with Atree;    use Atree;
  27 with Checks;   use Checks;
  28 with Einfo;    use Einfo;
  29 with Elists;   use Elists;
  30 with Errout;   use Errout;
  31 with Exp_Atag; use Exp_Atag;
  32 with Exp_Ch4;  use Exp_Ch4;
  33 with Exp_Ch7;  use Exp_Ch7;
  34 with Exp_Ch11; use Exp_Ch11;
  35 with Exp_Code; use Exp_Code;
  36 with Exp_Fixd; use Exp_Fixd;
  37 with Exp_Util; use Exp_Util;
  38 with Freeze;   use Freeze;
  39 with Namet;    use Namet;
  40 with Nmake;    use Nmake;
  41 with Nlists;   use Nlists;
  42 with Restrict; use Restrict;
  43 with Rident;   use Rident;
  44 with Rtsfind;  use Rtsfind;
  45 with Sem;      use Sem;
  46 with Sem_Eval; use Sem_Eval;
  47 with Sem_Res;  use Sem_Res;
  48 with Sem_Type; use Sem_Type;
  49 with Sem_Util; use Sem_Util;
  50 with Sinfo;    use Sinfo;
  51 with Sinput;   use Sinput;
  52 with Snames;   use Snames;
  53 with Stand;    use Stand;
  54 with Stringt;  use Stringt;
  55 with Targparm; use Targparm;
  56 with Tbuild;   use Tbuild;
  57 with Uintp;    use Uintp;
  58 with Urealp;   use Urealp;
  59
  60 package body Exp_Intr is
  61
  62    -----------------------
  63    -- Local Subprograms --
  64    -----------------------
  65
  66    procedure Expand_Is_Negative (N : Node_Id);
  67    --  Expand a call to the intrinsic Is_Negative function
  68
  69    procedure Expand_Dispatching_Constructor_Call (N : Node_Id);
  70    --  Expand a call to an instantiation of Generic_Dispatching_Constructor
  71    --  into a dispatching call to the actual subprogram associated with the
  72    --  Constructor formal subprogram, passing it the Parameters actual of
  73    --  the call to the instantiation and dispatching based on call's Tag
  74    --  parameter.
  75
  76    procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id);
  77    --  Expand a call to Exception_Information/Message/Name. The first
  78    --  parameter, N, is the node for the function call, and Ent is the
  79    --  entity for the corresponding routine in the Ada.Exceptions package.
  80
  81    procedure Expand_Import_Call (N : Node_Id);
  82    --  Expand a call to Import_Address/Longest_Integer/Value. The parameter
  83    --  N is the node for the function call.
  84
  85    procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind);
  86    --  Expand an intrinsic shift operation, N and E are from the call to
  87    --  Expand_Intrinsic_Call (call node and subprogram spec entity) and
  88    --  K is the kind for the shift node
  89
  90    procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id);
  91    --  Expand a call to an instantiation of Unchecked_Conversion into a node
  92    --  N_Unchecked_Type_Conversion.
  93
  94    procedure Expand_Unc_Deallocation (N : Node_Id);
  95    --  Expand a call to an instantiation of Unchecked_Deallocation into a node
  96    --  N_Free_Statement and appropriate context.
  97
  98    procedure Expand_To_Address (N : Node_Id);
  99    procedure Expand_To_Pointer (N : Node_Id);
 100    --  Expand a call to corresponding function, declared in an instance of
 101    --  System.Address_To_Access_Conversions.
 102
 103    procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id);
 104    --  Rewrite the node by the appropriate string or positive constant.
 105    --  Nam can be one of the following:
 106    --    Name_File             - expand string that is the name of source file
 107    --    Name_Line             - expand integer line number
 108    --    Name_Source_Location  - expand string of form file:line
 109    --    Name_Enclosing_Entity - expand string  with name of enclosing entity
 110
 111    -----------------------------------------
 112    -- Expand_Dispatching_Constructor_Call --
 113    -----------------------------------------
 114
 115    --  Transform a call to an instantiation of Generic_Dispatching_Constructor
 116    --  of the form:
 117
 118    --     GDC_Instance (The_Tag, Parameters'Access)
 119
 120    --  to a class-wide conversion of a dispatching call to the actual
 121    --  associated with the formal subprogram Construct, designating The_Tag
 122    --  as the controlling tag of the call:
 123
 124    --     T'Class (Construct'Actual (Params)) -- Controlling tag is The_Tag
 125
 126    --  which will eventually be expanded to the following:
 127
 128    --     T'Class (The_Tag.all (Construct'Actual'Index).all (Params))
 129
 130    --  A class-wide membership test is also generated, preceding the call, to
 131    --  ensure that the controlling tag denotes a type in T'Class.
 132
 133    procedure Expand_Dispatching_Constructor_Call (N : Node_Id) is
 134       Loc        : constant Source_Ptr := Sloc (N);
 135       Tag_Arg    : constant Node_Id    := First_Actual (N);
 136       Param_Arg  : constant Node_Id    := Next_Actual (Tag_Arg);
 137       Subp_Decl  : constant Node_Id    := Parent (Parent (Entity (Name (N))));
 138       Inst_Pkg   : constant Node_Id    := Parent (Subp_Decl);
 139       Act_Rename : Node_Id;
 140       Act_Constr : Entity_Id;
 141       Iface_Tag  : Node_Id := Empty;
 142       Cnstr_Call : Node_Id;
 143       Result_Typ : Entity_Id;
 144
 145    begin
 146       --  The subprogram is the third actual in the instantiation, and is
 147       --  retrieved from the corresponding renaming declaration. However,
 148       --  freeze nodes may appear before, so we retrieve the declaration
 149       --  with an explicit loop.
 150
 151       Act_Rename := First (Visible_Declarations (Inst_Pkg));
 152       while Nkind (Act_Rename) /= N_Subprogram_Renaming_Declaration loop
 153          Next (Act_Rename);
 154       end loop;
 155
 156       Act_Constr := Entity (Name (Act_Rename));
 157       Result_Typ := Class_Wide_Type (Etype (Act_Constr));
 158
 159       --  Ada 2005 (AI-251): If the result is an interface type, the function
 160       --  returns a class-wide interface type (otherwise the resulting object
 161       --  would be abstract!)
 162
 163       if Is_Interface (Etype (Act_Constr)) then
 164          Set_Etype (Act_Constr, Result_Typ);
 165
 166          --  If the result type is not parent of Tag_Arg then we need to
 167          --  locate the tag of the secondary dispatch table.
 168
 169          if not Is_Ancestor (Etype (Result_Typ), Etype (Tag_Arg)) then
 170             pragma Assert (not Is_Interface (Etype (Tag_Arg)));
 171
 172             Iface_Tag :=
 173               Make_Object_Declaration (Loc,
 174                 Defining_Identifier =>
 175                   Make_Defining_Identifier (Loc, New_Internal_Name ('V')),
 176                 Object_Definition =>
 177                   New_Reference_To (RTE (RE_Tag), Loc),
 178                 Expression =>
 179                   Make_Function_Call (Loc,
 180                     Name => New_Reference_To (RTE (RE_Secondary_Tag), Loc),
 181                     Parameter_Associations => New_List (
 182                       Relocate_Node (Tag_Arg),
 183                       New_Reference_To
 184                         (Node (First_Elmt (Access_Disp_Table
 185                                             (Etype (Etype (Act_Constr))))),
 186                          Loc))));
 187             Insert_Action (N, Iface_Tag);
 188          end if;
 189       end if;
 190
 191       --  Create the call to the actual Constructor function
 192
 193       Cnstr_Call :=
 194         Make_Function_Call (Loc,
 195           Name                   => New_Occurrence_Of (Act_Constr, Loc),
 196           Parameter_Associations => New_List (Relocate_Node (Param_Arg)));
 197
 198       --  Establish its controlling tag from the tag passed to the instance
 199       --  The tag may be given by a function call, in which case a temporary
 200       --  should be generated now, to prevent out-of-order insertions during
 201       --  the expansion of that call when stack-checking is enabled.
 202
 203       if Present (Iface_Tag) then
 204          Set_Controlling_Argument (Cnstr_Call,
 205            New_Occurrence_Of (Defining_Identifier (Iface_Tag), Loc));
 206       else
 207          Remove_Side_Effects (Tag_Arg);
 208          Set_Controlling_Argument (Cnstr_Call,
 209            Relocate_Node (Tag_Arg));
 210       end if;
 211
 212       --  Rewrite and analyze the call to the instance as a class-wide
 213       --  conversion of the call to the actual constructor.
 214
 215       Rewrite (N, Convert_To (Result_Typ, Cnstr_Call));
 216       Analyze_And_Resolve (N, Etype (Act_Constr));
 217
 218       --  Do not generate a run-time check on the built object if tag
 219       --  checks are suppressed for the result type or VM_Target /= No_VM
 220
 221       if Tag_Checks_Suppressed (Etype (Result_Typ))
 222         or else VM_Target /= No_VM
 223       then
 224          null;
 225
 226       --  Generate a class-wide membership test to ensure that the call's tag
 227       --  argument denotes a type within the class. We must keep separate the
 228       --  case in which the Result_Type of the constructor function is a tagged
 229       --  type from the case in which it is an abstract interface because the
 230       --  run-time subprogram required to check these cases differ (and have
 231       --  one difference in their parameters profile).
 232
 233       --  Call CW_Membership if the Result_Type is a tagged type to look for
 234       --  the tag in the table of ancestor tags.
 235
 236       elsif not Is_Interface (Result_Typ) then
 237          Insert_Action (N,
 238            Make_Implicit_If_Statement (N,
 239              Condition =>
 240                Make_Op_Not (Loc,
 241                  Build_CW_Membership (Loc,
 242                    Obj_Tag_Node => Duplicate_Subexpr (Tag_Arg),
 243                    Typ_Tag_Node =>
 244                      New_Reference_To (
 245                         Node (First_Elmt (Access_Disp_Table (
 246                                             Root_Type (Result_Typ)))), Loc))),
 247              Then_Statements =>
 248                New_List (Make_Raise_Statement (Loc,
 249                            New_Occurrence_Of (RTE (RE_Tag_Error), Loc)))));
 250
 251       --  Call IW_Membership test if the Result_Type is an abstract interface
 252       --  to look for the tag in the table of interface tags.
 253
 254       else
 255          Insert_Action (N,
 256            Make_Implicit_If_Statement (N,
 257              Condition =>
 258                Make_Op_Not (Loc,
 259                  Make_Function_Call (Loc,
 260                     Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc),
 261                     Parameter_Associations => New_List (
 262                       Make_Attribute_Reference (Loc,
 263                         Prefix         => Duplicate_Subexpr (Tag_Arg),
 264                         Attribute_Name => Name_Address),
 265
 266                       New_Reference_To (
 267                         Node (First_Elmt (Access_Disp_Table (
 268                                             Root_Type (Result_Typ)))), Loc)))),
 269              Then_Statements =>
 270                New_List (
 271                  Make_Raise_Statement (Loc,
 272                    Name => New_Occurrence_Of (RTE (RE_Tag_Error), Loc)))));
 273       end if;
 274    end Expand_Dispatching_Constructor_Call;
 275
 276    ---------------------------
 277    -- Expand_Exception_Call --
 278    ---------------------------
 279
 280    --  If the function call is not within an exception handler, then the call
 281    --  is replaced by a null string. Otherwise the appropriate routine in
 282    --  Ada.Exceptions is called passing the choice parameter specification
 283    --  from the enclosing handler. If the enclosing handler lacks a choice
 284    --  parameter, then one is supplied.
 285
 286    procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id) is
 287       Loc : constant Source_Ptr := Sloc (N);
 288       P   : Node_Id;
 289       E   : Entity_Id;
 290
 291    begin
 292       --  Climb up parents to see if we are in exception handler
 293
 294       P := Parent (N);
 295       loop
 296          --  Case of not in exception handler, replace by null string
 297
 298          if No (P) then
 299             Rewrite (N,
 300               Make_String_Literal (Loc,
 301                 Strval => ""));
 302             exit;
 303
 304          --  Case of in exception handler
 305
 306          elsif Nkind (P) = N_Exception_Handler then
 307
 308             --  Handler cannot be used for a local raise, and furthermore, this
 309             --  is a violation of the No_Exception_Propagation restriction.
 310
 311             Set_Local_Raise_Not_OK (P);
 312             Check_Restriction (No_Exception_Propagation, N);
 313
 314             --  If no choice parameter present, then put one there. Note that
 315             --  we do not need to put it on the entity chain, since no one will
 316             --  be referencing it by normal visibility methods.
 317
 318             if No (Choice_Parameter (P)) then
 319                E := Make_Defining_Identifier (Loc, New_Internal_Name ('E'));
 320                Set_Choice_Parameter (P, E);
 321                Set_Ekind (E, E_Variable);
 322                Set_Etype (E, RTE (RE_Exception_Occurrence));
 323                Set_Scope (E, Current_Scope);
 324             end if;
 325
 326             Rewrite (N,
 327               Make_Function_Call (Loc,
 328                 Name => New_Occurrence_Of (RTE (Ent), Loc),
 329                 Parameter_Associations => New_List (
 330                   New_Occurrence_Of (Choice_Parameter (P), Loc))));
 331             exit;
 332
 333          --  Keep climbing!
 334
 335          else
 336             P := Parent (P);
 337          end if;
 338       end loop;
 339
 340       Analyze_And_Resolve (N, Standard_String);
 341    end Expand_Exception_Call;
 342
 343    ------------------------
 344    -- Expand_Import_Call --
 345    ------------------------
 346
 347    --  The function call must have a static string as its argument. We create
 348    --  a dummy variable which uses this string as the external name in an
 349    --  Import pragma. The result is then obtained as the address of this
 350    --  dummy variable, converted to the appropriate target type.
 351
 352    procedure Expand_Import_Call (N : Node_Id) is
 353       Loc : constant Source_Ptr := Sloc (N);
 354       Ent : constant Entity_Id  := Entity (Name (N));
 355       Str : constant Node_Id    := First_Actual (N);
 356       Dum : Entity_Id;
 357
 358    begin
 359       Dum := Make_Defining_Identifier (Loc, New_Internal_Name ('D'));
 360
 361       Insert_Actions (N, New_List (
 362         Make_Object_Declaration (Loc,
 363           Defining_Identifier => Dum,
 364           Object_Definition   =>
 365             New_Occurrence_Of (Standard_Character, Loc)),
 366
 367         Make_Pragma (Loc,
 368           Chars => Name_Import,
 369           Pragma_Argument_Associations => New_List (
 370             Make_Pragma_Argument_Association (Loc,
 371               Expression => Make_Identifier (Loc, Name_Ada)),
 372
 373             Make_Pragma_Argument_Association (Loc,
 374               Expression => Make_Identifier (Loc, Chars (Dum))),
 375
 376             Make_Pragma_Argument_Association (Loc,
 377               Chars => Name_Link_Name,
 378               Expression => Relocate_Node (Str))))));
 379
 380       Rewrite (N,
 381         Unchecked_Convert_To (Etype (Ent),
 382           Make_Attribute_Reference (Loc,
 383             Prefix         => Make_Identifier (Loc, Chars (Dum)),
 384             Attribute_Name => Name_Address)));
 385
 386       Analyze_And_Resolve (N, Etype (Ent));
 387    end Expand_Import_Call;
 388
 389    ---------------------------
 390    -- Expand_Intrinsic_Call --
 391    ---------------------------
 392
 393    procedure Expand_Intrinsic_Call (N : Node_Id; E : Entity_Id) is
 394       Nam : Name_Id;
 395
 396    begin
 397       --  If the intrinsic subprogram is generic, gets its original name
 398
 399       if Present (Parent (E))
 400         and then Present (Generic_Parent (Parent (E)))
 401       then
 402          Nam := Chars (Generic_Parent (Parent (E)));
 403       else
 404          Nam := Chars (E);
 405       end if;
 406
 407       if Nam = Name_Asm then
 408          Expand_Asm_Call (N);
 409
 410       elsif Nam = Name_Divide then
 411          Expand_Decimal_Divide_Call (N);
 412
 413       elsif Nam = Name_Exception_Information then
 414          Expand_Exception_Call (N, RE_Exception_Information);
 415
 416       elsif Nam = Name_Exception_Message then
 417          Expand_Exception_Call (N, RE_Exception_Message);
 418
 419       elsif Nam = Name_Exception_Name then
 420          Expand_Exception_Call (N, RE_Exception_Name_Simple);
 421
 422       elsif Nam = Name_Generic_Dispatching_Constructor then
 423          Expand_Dispatching_Constructor_Call (N);
 424
 425       elsif Nam = Name_Import_Address
 426               or else
 427             Nam = Name_Import_Largest_Value
 428               or else
 429             Nam = Name_Import_Value
 430       then
 431          Expand_Import_Call (N);
 432
 433       elsif Nam = Name_Is_Negative then
 434          Expand_Is_Negative (N);
 435
 436       elsif Nam = Name_Rotate_Left then
 437          Expand_Shift (N, E, N_Op_Rotate_Left);
 438
 439       elsif Nam = Name_Rotate_Right then
 440          Expand_Shift (N, E, N_Op_Rotate_Right);
 441
 442       elsif Nam = Name_Shift_Left then
 443          Expand_Shift (N, E, N_Op_Shift_Left);
 444
 445       elsif Nam = Name_Shift_Right then
 446          Expand_Shift (N, E, N_Op_Shift_Right);
 447
 448       elsif Nam = Name_Shift_Right_Arithmetic then
 449          Expand_Shift (N, E, N_Op_Shift_Right_Arithmetic);
 450
 451       elsif Nam = Name_Unchecked_Conversion then
 452          Expand_Unc_Conversion (N, E);
 453
 454       elsif Nam = Name_Unchecked_Deallocation then
 455          Expand_Unc_Deallocation (N);
 456
 457       elsif Nam = Name_To_Address then
 458          Expand_To_Address (N);
 459
 460       elsif Nam = Name_To_Pointer then
 461          Expand_To_Pointer (N);
 462
 463       elsif Nam = Name_File
 464         or else Nam = Name_Line
 465         or else Nam = Name_Source_Location
 466         or else Nam = Name_Enclosing_Entity
 467       then
 468          Expand_Source_Info (N, Nam);
 469
 470          --  If we have a renaming, expand the call to the original operation,
 471          --  which must itself be intrinsic, since renaming requires matching
 472          --  conventions and this has already been checked.
 473
 474       elsif Present (Alias (E)) then
 475          Expand_Intrinsic_Call (N,  Alias (E));
 476
 477          --  The only other case is where an external name was specified,
 478          --  since this is the only way that an otherwise unrecognized
 479          --  name could escape the checking in Sem_Prag. Nothing needs
 480          --  to be done in such a case, since we pass such a call to the
 481          --  back end unchanged.
 482
 483       else
 484          null;
 485       end if;
 486    end Expand_Intrinsic_Call;
 487
 488    ------------------------
 489    -- Expand_Is_Negative --
 490    ------------------------
 491
 492    procedure Expand_Is_Negative (N : Node_Id) is
 493       Loc   : constant Source_Ptr := Sloc (N);
 494       Opnd  : constant Node_Id    := Relocate_Node (First_Actual (N));
 495
 496    begin
 497
 498       --  We replace the function call by the following expression
 499
 500       --    if Opnd < 0.0 then
 501       --       True
 502       --    else
 503       --       if Opnd > 0.0 then
 504       --          False;
 505       --       else
 506       --          Float_Unsigned!(Float (Opnd)) /= 0
 507       --       end if;
 508       --    end if;
 509
 510       Rewrite (N,
 511         Make_Conditional_Expression (Loc,
 512           Expressions => New_List (
 513             Make_Op_Lt (Loc,
 514               Left_Opnd  => Duplicate_Subexpr (Opnd),
 515               Right_Opnd => Make_Real_Literal (Loc, Ureal_0)),
 516
 517             New_Occurrence_Of (Standard_True, Loc),
 518
 519             Make_Conditional_Expression (Loc,
 520              Expressions => New_List (
 521                Make_Op_Gt (Loc,
 522                  Left_Opnd  => Duplicate_Subexpr_No_Checks (Opnd),
 523                  Right_Opnd => Make_Real_Literal (Loc, Ureal_0)),
 524
 525                New_Occurrence_Of (Standard_False, Loc),
 526
 527                 Make_Op_Ne (Loc,
 528                   Left_Opnd =>
 529                     Unchecked_Convert_To
 530                       (RTE (RE_Float_Unsigned),
 531                        Convert_To
 532                          (Standard_Float,
 533                           Duplicate_Subexpr_No_Checks (Opnd))),
 534                   Right_Opnd =>
 535                     Make_Integer_Literal (Loc, 0)))))));
 536
 537       Analyze_And_Resolve (N, Standard_Boolean);
 538    end Expand_Is_Negative;
 539
 540    ------------------
 541    -- Expand_Shift --
 542    ------------------
 543
 544    --  This procedure is used to convert a call to a shift function to the
 545    --  corresponding operator node. This conversion is not done by the usual
 546    --  circuit for converting calls to operator functions (e.g. "+"(1,2)) to
 547    --  operator nodes, because shifts are not predefined operators.
 548
 549    --  As a result, whenever a shift is used in the source program, it will
 550    --  remain as a call until converted by this routine to the operator node
 551    --  form which Gigi is expecting to see.
 552
 553    --  Note: it is possible for the expander to generate shift operator nodes
 554    --  directly, which will be analyzed in the normal manner by calling Analyze
 555    --  and Resolve. Such shift operator nodes will not be seen by Expand_Shift.
 556
 557    procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind) is
 558       Loc   : constant Source_Ptr := Sloc (N);
 559       Typ   : constant Entity_Id  := Etype (N);
 560       Left  : constant Node_Id    := First_Actual (N);
 561       Right : constant Node_Id    := Next_Actual (Left);
 562       Ltyp  : constant Node_Id    := Etype (Left);
 563       Rtyp  : constant Node_Id    := Etype (Right);
 564       Snode : Node_Id;
 565
 566    begin
 567       Snode := New_Node (K, Loc);
 568       Set_Left_Opnd  (Snode, Relocate_Node (Left));
 569       Set_Right_Opnd (Snode, Relocate_Node (Right));
 570       Set_Chars      (Snode, Chars (E));
 571       Set_Etype      (Snode, Base_Type (Typ));
 572       Set_Entity     (Snode, E);
 573
 574       if Compile_Time_Known_Value (Type_High_Bound (Rtyp))
 575         and then Expr_Value (Type_High_Bound (Rtyp)) < Esize (Ltyp)
 576       then
 577          Set_Shift_Count_OK (Snode, True);
 578       end if;
 579
 580       --  Do the rewrite. Note that we don't call Analyze and Resolve on
 581       --  this node, because it already got analyzed and resolved when
 582       --  it was a function call!
 583
 584       Rewrite (N, Snode);
 585       Set_Analyzed (N);
 586    end Expand_Shift;
 587
 588    ------------------------
 589    -- Expand_Source_Info --
 590    ------------------------
 591
 592    procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id) is
 593       Loc : constant Source_Ptr := Sloc (N);
 594       Ent : Entity_Id;
 595
 596       procedure Write_Entity_Name (E : Entity_Id);
 597       --  Recursive procedure to construct string for qualified name of
 598       --  enclosing program unit. The qualification stops at an enclosing
 599       --  scope has no source name (block or loop). If entity is a subprogram
 600       --  instance, skip enclosing wrapper package.
 601
 602       -----------------------
 603       -- Write_Entity_Name --
 604       -----------------------
 605
 606       procedure Write_Entity_Name (E : Entity_Id) is
 607          SDef : Source_Ptr;
 608          TDef : constant Source_Buffer_Ptr :=
 609                   Source_Text (Get_Source_File_Index (Sloc (E)));
 610
 611       begin
 612          --  Nothing to do if at outer level
 613
 614          if Scope (E) = Standard_Standard then
 615             null;
 616
 617          --  If scope comes from source, write its name
 618
 619          elsif Comes_From_Source (Scope (E)) then
 620             Write_Entity_Name (Scope (E));
 621             Add_Char_To_Name_Buffer ('.');
 622
 623          --  If in wrapper package skip past it
 624
 625          elsif Is_Wrapper_Package (Scope (E)) then
 626             Write_Entity_Name (Scope (Scope (E)));
 627             Add_Char_To_Name_Buffer ('.');
 628
 629          --  Otherwise nothing to output (happens in unnamed block statements)
 630
 631          else
 632             null;
 633          end if;
 634
 635          --  Loop to output the name
 636
 637          --  is this right wrt wide char encodings ??? (no!)
 638
 639          SDef := Sloc (E);
 640          while TDef (SDef) in '0' .. '9'
 641            or else TDef (SDef) >= 'A'
 642            or else TDef (SDef) = ASCII.ESC
 643          loop
 644             Add_Char_To_Name_Buffer (TDef (SDef));
 645             SDef := SDef + 1;
 646          end loop;
 647       end Write_Entity_Name;
 648
 649    --  Start of processing for Expand_Source_Info
 650
 651    begin
 652       --  Integer cases
 653
 654       if Nam = Name_Line then
 655          Rewrite (N,
 656            Make_Integer_Literal (Loc,
 657              Intval => UI_From_Int (Int (Get_Logical_Line_Number (Loc)))));
 658          Analyze_And_Resolve (N, Standard_Positive);
 659
 660       --  String cases
 661
 662       else
 663          Name_Len := 0;
 664
 665          case Nam is
 666             when Name_File =>
 667                Get_Decoded_Name_String
 668                  (Reference_Name (Get_Source_File_Index (Loc)));
 669
 670             when Name_Source_Location =>
 671                Build_Location_String (Loc);
 672
 673             when Name_Enclosing_Entity =>
 674
 675                --  Skip enclosing blocks to reach enclosing unit
 676
 677                Ent := Current_Scope;
 678                while Present (Ent) loop
 679                   exit when Ekind (Ent) /= E_Block
 680                     and then Ekind (Ent) /= E_Loop;
 681                   Ent := Scope (Ent);
 682                end loop;
 683
 684                --  Ent now points to the relevant defining entity
 685
 686                Write_Entity_Name (Ent);
 687
 688             when others =>
 689                raise Program_Error;
 690          end case;
 691
 692          Rewrite (N,
 693            Make_String_Literal (Loc,
 694              Strval => String_From_Name_Buffer));
 695          Analyze_And_Resolve (N, Standard_String);
 696       end if;
 697
 698       Set_Is_Static_Expression (N);
 699    end Expand_Source_Info;
 700
 701    ---------------------------
 702    -- Expand_Unc_Conversion --
 703    ---------------------------
 704
 705    procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id) is
 706       Func : constant Entity_Id  := Entity (Name (N));
 707       Conv : Node_Id;
 708       Ftyp : Entity_Id;
 709       Ttyp : Entity_Id;
 710
 711    begin
 712       --  Rewrite as unchecked conversion node. Note that we must convert
 713       --  the operand to the formal type of the input parameter of the
 714       --  function, so that the resulting N_Unchecked_Type_Conversion
 715       --  call indicates the correct types for Gigi.
 716
 717       --  Right now, we only do this if a scalar type is involved. It is
 718       --  not clear if it is needed in other cases. If we do attempt to
 719       --  do the conversion unconditionally, it crashes 3411-018. To be
 720       --  investigated further ???
 721
 722       Conv := Relocate_Node (First_Actual (N));
 723       Ftyp := Etype (First_Formal (Func));
 724
 725       if Is_Scalar_Type (Ftyp) then
 726          Conv := Convert_To (Ftyp, Conv);
 727          Set_Parent (Conv, N);
 728          Analyze_And_Resolve (Conv);
 729       end if;
 730
 731       --  The instantiation of Unchecked_Conversion creates a wrapper package,
 732       --  and the target type is declared as a subtype of the actual. Recover
 733       --  the actual, which is the subtype indic. in the subtype declaration
 734       --  for the target type. This is semantically correct, and avoids
 735       --  anomalies with access subtypes. For entities, leave type as is.
 736
 737       --  We do the analysis here, because we do not want the compiler
 738       --  to try to optimize or otherwise reorganize the unchecked
 739       --  conversion node.
 740
 741       Ttyp := Etype (E);
 742
 743       if Is_Entity_Name (Conv) then
 744          null;
 745
 746       elsif Nkind (Parent (Ttyp)) = N_Subtype_Declaration then
 747          Ttyp := Entity (Subtype_Indication (Parent (Etype (E))));
 748
 749       elsif Is_Itype (Ttyp) then
 750          Ttyp :=
 751            Entity (Subtype_Indication (Associated_Node_For_Itype (Ttyp)));
 752       else
 753          raise Program_Error;
 754       end if;
 755
 756       Rewrite (N, Unchecked_Convert_To (Ttyp, Conv));
 757       Set_Etype (N, Ttyp);
 758       Set_Analyzed (N);
 759
 760       if Nkind (N) = N_Unchecked_Type_Conversion then
 761          Expand_N_Unchecked_Type_Conversion (N);
 762       end if;
 763    end Expand_Unc_Conversion;
 764
 765    -----------------------------
 766    -- Expand_Unc_Deallocation --
 767    -----------------------------
 768
 769    --  Generate the following Code :
 770
 771    --    if Arg /= null then
 772    --     <Finalize_Call> (.., T'Class(Arg.all), ..);  -- for controlled types
 773    --       Free (Arg);
 774    --       Arg := Null;
 775    --    end if;
 776
 777    --  For a task, we also generate a call to Free_Task to ensure that the
 778    --  task itself is freed if it is terminated, ditto for a simple protected
 779    --  object, with a call to Finalize_Protection. For composite types that
 780    --  have tasks or simple protected objects as components, we traverse the
 781    --  structures to find and terminate those components.
 782
 783    procedure Expand_Unc_Deallocation (N : Node_Id) is
 784       Loc   : constant Source_Ptr := Sloc (N);
 785       Arg   : constant Node_Id    := First_Actual (N);
 786       Typ   : constant Entity_Id  := Etype (Arg);
 787       Stmts : constant List_Id    := New_List;
 788       Rtyp  : constant Entity_Id  := Underlying_Type (Root_Type (Typ));
 789       Pool  : constant Entity_Id  := Associated_Storage_Pool (Rtyp);
 790
 791       Desig_T   : constant Entity_Id  := Designated_Type (Typ);
 792       Gen_Code  : Node_Id;
 793       Free_Node : Node_Id;
 794       Deref     : Node_Id;
 795       Free_Arg  : Node_Id;
 796       Free_Cod  : List_Id;
 797       Blk       : Node_Id;
 798
 799       Arg_Known_Non_Null : constant Boolean := Known_Non_Null (N);
 800       --  This captures whether we know the argument to be non-null so that
 801       --  we can avoid the test. The reason that we need to capture this is
 802       --  that we analyze some generated statements before properly attaching
 803       --  them to the tree, and that can disturb current value settings.
 804
 805    begin
 806       if No_Pool_Assigned (Rtyp) then
 807          Error_Msg_N ("?deallocation from empty storage pool!", N);
 808       end if;
 809
 810       --  Nothing to do if we know the argument is null
 811
 812       if Known_Null (N) then
 813          return;
 814       end if;
 815
 816       --  Processing for pointer to controlled type
 817
 818       if Needs_Finalization (Desig_T) then
 819          Deref :=
 820            Make_Explicit_Dereference (Loc,
 821              Prefix => Duplicate_Subexpr_No_Checks (Arg));
 822
 823          --  If the type is tagged, then we must force dispatching on the
 824          --  finalization call because the designated type may not be the
 825          --  actual type of the object.
 826
 827          if Is_Tagged_Type (Desig_T)
 828            and then not Is_Class_Wide_Type (Desig_T)
 829          then
 830             Deref := Unchecked_Convert_To (Class_Wide_Type (Desig_T), Deref);
 831
 832          elsif not Is_Tagged_Type (Desig_T) then
 833
 834             --  Set type of result, to force a conversion when needed (see
 835             --  exp_ch7, Convert_View), given that Deep_Finalize may be
 836             --  inherited from the parent type, and we need the type of the
 837             --  expression to see whether the conversion is in fact needed.
 838
 839             Set_Etype (Deref, Desig_T);
 840          end if;
 841
 842          Free_Cod :=
 843            Make_Final_Call
 844             (Ref         => Deref,
 845              Typ         => Desig_T,
 846              With_Detach => New_Reference_To (Standard_True, Loc));
 847
 848          if Abort_Allowed then
 849             Prepend_To (Free_Cod,
 850               Build_Runtime_Call (Loc, RE_Abort_Defer));
 851
 852             Blk :=
 853               Make_Block_Statement (Loc, Handled_Statement_Sequence =>
 854                 Make_Handled_Sequence_Of_Statements (Loc,
 855                   Statements  => Free_Cod,
 856                   At_End_Proc =>
 857                     New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc)));
 858
 859             --  We now expand the exception (at end) handler. We set a
 860             --  temporary parent pointer since we have not attached Blk
 861             --  to the tree yet.
 862
 863             Set_Parent (Blk, N);
 864             Analyze (Blk);
 865             Expand_At_End_Handler
 866               (Handled_Statement_Sequence (Blk), Entity (Identifier (Blk)));
 867             Append (Blk, Stmts);
 868
 869             --  We kill saved current values, since analyzing statements not
 870             --  properly attached to the tree can set wrong current values.
 871
 872             Kill_Current_Values;
 873
 874          else
 875             Append_List_To (Stmts, Free_Cod);
 876          end if;
 877       end if;
 878
 879       --  For a task type, call Free_Task before freeing the ATCB
 880
 881       if Is_Task_Type (Desig_T) then
 882          declare
 883             Stat : Node_Id := Prev (N);
 884             Nam1 : Node_Id;
 885             Nam2 : Node_Id;
 886
 887          begin
 888             --  An Abort followed by a Free will not do what the user
 889             --  expects, because the abort is not immediate. This is
 890             --  worth a friendly warning.
 891
 892             while Present (Stat)
 893               and then not Comes_From_Source (Original_Node (Stat))
 894             loop
 895                Prev (Stat);
 896             end loop;
 897
 898             if Present (Stat)
 899               and then Nkind (Original_Node (Stat)) = N_Abort_Statement
 900             then
 901                Stat := Original_Node (Stat);
 902                Nam1 := First (Names (Stat));
 903                Nam2 := Original_Node (First (Parameter_Associations (N)));
 904
 905                if Nkind (Nam1) = N_Explicit_Dereference
 906                  and then Is_Entity_Name (Prefix (Nam1))
 907                  and then Is_Entity_Name (Nam2)
 908                  and then Entity (Prefix (Nam1)) = Entity (Nam2)
 909                then
 910                   Error_Msg_N ("abort may take time to complete?", N);
 911                   Error_Msg_N ("\deallocation might have no effect?", N);
 912                   Error_Msg_N ("\safer to wait for termination.?", N);
 913                end if;
 914             end if;
 915          end;
 916
 917          Append_To
 918            (Stmts, Cleanup_Task (N, Duplicate_Subexpr_No_Checks (Arg)));
 919
 920       --  For composite types that contain tasks, recurse over the structure
 921       --  to build the selectors for the task subcomponents.
 922
 923       elsif Has_Task (Desig_T) then
 924          if Is_Record_Type (Desig_T) then
 925             Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T));
 926
 927          elsif Is_Array_Type (Desig_T) then
 928             Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T));
 929          end if;
 930       end if;
 931
 932       --  Same for simple protected types. Eventually call Finalize_Protection
 933       --  before freeing the PO for each protected component.
 934
 935       if Is_Simple_Protected_Type (Desig_T) then
 936          Append_To (Stmts,
 937            Cleanup_Protected_Object (N, Duplicate_Subexpr_No_Checks (Arg)));
 938
 939       elsif Has_Simple_Protected_Object (Desig_T) then
 940          if Is_Record_Type (Desig_T) then
 941             Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T));
 942          elsif Is_Array_Type (Desig_T) then
 943             Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T));
 944          end if;
 945       end if;
 946
 947       --  Normal processing for non-controlled types
 948
 949       Free_Arg := Duplicate_Subexpr_No_Checks (Arg);
 950       Free_Node := Make_Free_Statement (Loc, Empty);
 951       Append_To (Stmts, Free_Node);
 952       Set_Storage_Pool (Free_Node, Pool);
 953
 954       --  Deal with storage pool
 955
 956       if Present (Pool) then
 957
 958          --  Freeing the secondary stack is meaningless
 959
 960          if Is_RTE (Pool, RE_SS_Pool) then
 961             null;
 962
 963          elsif Is_Class_Wide_Type (Etype (Pool)) then
 964
 965             --  Case of a class-wide pool type: make a dispatching call
 966             --  to Deallocate through the class-wide Deallocate_Any.
 967
 968             Set_Procedure_To_Call (Free_Node,
 969               RTE (RE_Deallocate_Any));
 970
 971          else
 972             --  Case of a specific pool type: make a statically bound call
 973
 974             Set_Procedure_To_Call (Free_Node,
 975               Find_Prim_Op (Etype (Pool), Name_Deallocate));
 976          end if;
 977       end if;
 978
 979       if Present (Procedure_To_Call (Free_Node)) then
 980
 981          --  For all cases of a Deallocate call, the back-end needs to be
 982          --  able to compute the size of the object being freed. This may
 983          --  require some adjustments for objects of dynamic size.
 984          --
 985          --  If the type is class wide, we generate an implicit type with the
 986          --  right dynamic size, so that the deallocate call gets the right
 987          --  size parameter computed by GIGI. Same for an access to
 988          --  unconstrained packed array.
 989
 990          if Is_Class_Wide_Type (Desig_T)
 991            or else
 992             (Is_Array_Type (Desig_T)
 993                and then not Is_Constrained (Desig_T)
 994                and then Is_Packed (Desig_T))
 995          then
 996             declare
 997                Deref    : constant Node_Id :=
 998                             Make_Explicit_Dereference (Loc,
 999                               Duplicate_Subexpr_No_Checks (Arg));
1000                D_Subtyp : Node_Id;
1001                D_Type   : Entity_Id;
1002
1003             begin
1004                Set_Etype  (Deref, Typ);
1005                Set_Parent (Deref, Free_Node);
1006                D_Subtyp := Make_Subtype_From_Expr (Deref, Desig_T);
1007
1008                if Nkind (D_Subtyp) in N_Has_Entity then
1009                   D_Type := Entity (D_Subtyp);
1010
1011                else
1012                   D_Type := Make_Defining_Identifier (Loc,
1013                               New_Internal_Name ('A'));
1014                   Insert_Action (N,
1015                     Make_Subtype_Declaration (Loc,
1016                       Defining_Identifier => D_Type,
1017                       Subtype_Indication  => D_Subtyp));
1018                   Freeze_Itype (D_Type, N);
1019
1020                end if;
1021
1022                Set_Actual_Designated_Subtype (Free_Node, D_Type);
1023             end;
1024
1025          end if;
1026       end if;
1027
1028       --  Ada 2005 (AI-251): In case of abstract interface type we must
1029       --  displace the pointer to reference the base of the object to
1030       --  deallocate its memory, unless we're targetting a VM, in which case
1031       --  no special processing is required.
1032
1033       --  Generate:
1034       --    free (Base_Address (Obj_Ptr))
1035
1036       if Is_Interface (Directly_Designated_Type (Typ))
1037         and then VM_Target = No_VM
1038       then
1039          Set_Expression (Free_Node,
1040            Unchecked_Convert_To (Typ,
1041              Make_Function_Call (Loc,
1042                Name => New_Reference_To (RTE (RE_Base_Address), Loc),
1043                Parameter_Associations => New_List (
1044                  Unchecked_Convert_To (RTE (RE_Address), Free_Arg)))));
1045
1046       --  Generate:
1047       --    free (Obj_Ptr)
1048
1049       else
1050          Set_Expression (Free_Node, Free_Arg);
1051       end if;
1052
1053       --  Only remaining step is to set result to null, or generate a
1054       --  raise of constraint error if the target object is "not null".
1055
1056       if Can_Never_Be_Null (Etype (Arg)) then
1057          Append_To (Stmts,
1058            Make_Raise_Constraint_Error (Loc,
1059              Reason => CE_Access_Check_Failed));
1060
1061       else
1062          declare
1063             Lhs : constant Node_Id := Duplicate_Subexpr_No_Checks (Arg);
1064          begin
1065             Set_Assignment_OK (Lhs);
1066             Append_To (Stmts,
1067               Make_Assignment_Statement (Loc,
1068                 Name       => Lhs,
1069                 Expression => Make_Null (Loc)));
1070          end;
1071       end if;
1072
1073       --  If we know the argument is non-null, then make a block statement
1074       --  that contains the required statements, no need for a test.
1075
1076       if Arg_Known_Non_Null then
1077          Gen_Code :=
1078            Make_Block_Statement (Loc,
1079              Handled_Statement_Sequence =>
1080                Make_Handled_Sequence_Of_Statements (Loc,
1081              Statements => Stmts));
1082
1083       --  If the argument may be null, wrap the statements inside an IF that
1084       --  does an explicit test to exclude the null case.
1085
1086       else
1087          Gen_Code :=
1088            Make_Implicit_If_Statement (N,
1089              Condition =>
1090                Make_Op_Ne (Loc,
1091                  Left_Opnd  => Duplicate_Subexpr (Arg),
1092                  Right_Opnd => Make_Null (Loc)),
1093              Then_Statements => Stmts);
1094       end if;
1095
1096       --  Rewrite the call
1097
1098       Rewrite (N, Gen_Code);
1099       Analyze (N);
1100    end Expand_Unc_Deallocation;
1101
1102    -----------------------
1103    -- Expand_To_Address --
1104    -----------------------
1105
1106    procedure Expand_To_Address (N : Node_Id) is
1107       Loc : constant Source_Ptr := Sloc (N);
1108       Arg : constant Node_Id := First_Actual (N);
1109       Obj : Node_Id;
1110
1111    begin
1112       Remove_Side_Effects (Arg);
1113
1114       Obj := Make_Explicit_Dereference (Loc, Relocate_Node (Arg));
1115
1116       Rewrite (N,
1117         Make_Conditional_Expression (Loc,
1118           Expressions => New_List (
1119             Make_Op_Eq (Loc,
1120               Left_Opnd => New_Copy_Tree (Arg),
1121               Right_Opnd => Make_Null (Loc)),
1122             New_Occurrence_Of (RTE (RE_Null_Address), Loc),
1123             Make_Attribute_Reference (Loc,
1124               Prefix         => Obj,
1125               Attribute_Name => Name_Address))));
1126
1127       Analyze_And_Resolve (N, RTE (RE_Address));
1128    end Expand_To_Address;
1129
1130    -----------------------
1131    -- Expand_To_Pointer --
1132    -----------------------
1133
1134    procedure Expand_To_Pointer (N : Node_Id) is
1135       Arg : constant Node_Id := First_Actual (N);
1136
1137    begin
1138       Rewrite (N, Unchecked_Convert_To (Etype (N), Arg));
1139       Analyze (N);
1140    end Expand_To_Pointer;
1141
1142 end Exp_Intr;