gcc/ada/exp_smem.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             E X P _ S M E M                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1998-2007, 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 Einfo;    use Einfo;
  28 with Exp_Util; use Exp_Util;
  29 with Nmake;    use Nmake;
  30 with Namet;    use Namet;
  31 with Nlists;   use Nlists;
  32 with Rtsfind;  use Rtsfind;
  33 with Sem;      use Sem;
  34 with Sem_Util; use Sem_Util;
  35 with Sinfo;    use Sinfo;
  36 with Snames;   use Snames;
  37 with Stand;    use Stand;
  38 with Stringt;  use Stringt;
  39 with Tbuild;   use Tbuild;
  40
  41 package body Exp_Smem is
  42
  43    Insert_Node : Node_Id;
  44    --  Node after which a write call is to be inserted
  45
  46    -----------------------
  47    -- Local Subprograms --
  48    -----------------------
  49
  50    procedure Add_Read_Before (N : Node_Id);
  51    --  Insert a Shared_Var_ROpen call for variable before node N
  52
  53    procedure Add_Write_After (N : Node_Id);
  54    --  Insert a Shared_Var_WOpen call for variable after the node
  55    --  Insert_Node, as recorded by On_Lhs_Of_Assigment (where it points
  56    --  to the assignment statement) or Is_Out_Actual (where it points to
  57    --  the procedure call statement).
  58
  59    procedure Build_Full_Name (E : Entity_Id; N : out String_Id);
  60    --  Build the fully qualified string name of a shared variable
  61
  62    function On_Lhs_Of_Assignment (N : Node_Id) return Boolean;
  63    --  Determines if N is on the left hand of the assignment. This means
  64    --  that either it is a simple variable, or it is a record or array
  65    --  variable with a corresponding selected or indexed component on
  66    --  the left side of an assignment. If the result is True, then
  67    --  Insert_Node is set to point to the assignment
  68
  69    function Is_Out_Actual (N : Node_Id) return Boolean;
  70    --  In a similar manner, this function determines if N appears as an
  71    --  OUT or IN OUT parameter to a procedure call. If the result is
  72    --  True, then Insert_Node is set to point to the call.
  73
  74    ---------------------
  75    -- Add_Read_Before --
  76    ---------------------
  77
  78    procedure Add_Read_Before (N : Node_Id) is
  79       Loc : constant Source_Ptr := Sloc (N);
  80       Ent : constant Node_Id    := Entity (N);
  81
  82    begin
  83       if Present (Shared_Var_Read_Proc (Ent)) then
  84          Insert_Action (N,
  85            Make_Procedure_Call_Statement (Loc,
  86              Name =>
  87                New_Occurrence_Of (Shared_Var_Read_Proc (Ent), Loc),
  88              Parameter_Associations => Empty_List));
  89       end if;
  90    end Add_Read_Before;
  91
  92    -------------------------------
  93    -- Add_Shared_Var_Lock_Procs --
  94    -------------------------------
  95
  96    procedure Add_Shared_Var_Lock_Procs (N : Node_Id) is
  97       Loc   : constant Source_Ptr := Sloc (N);
  98       Obj   : constant Entity_Id  := Entity (Expression (First_Actual (N)));
  99       Inode : Node_Id;
 100       Vnm   : String_Id;
 101
 102    begin
 103       --  We have to add Shared_Var_Lock and Shared_Var_Unlock calls around
 104       --  the procedure or function call node. First we locate the right
 105       --  place to do the insertion, which is the call itself in the
 106       --  procedure call case, or else the nearest non subexpression
 107       --  node that contains the function call.
 108
 109       Inode := N;
 110       while Nkind (Inode) /= N_Procedure_Call_Statement
 111         and then Nkind (Inode) in N_Subexpr
 112       loop
 113          Inode := Parent (Inode);
 114       end loop;
 115
 116       --  Now insert the Lock and Unlock calls and the read/write calls
 117
 118       --  Two concerns here. First we are not dealing with the exception
 119       --  case, really we need some kind of cleanup routine to do the
 120       --  Unlock. Second, these lock calls should be inside the protected
 121       --  object processing, not outside, otherwise they can be done at
 122       --  the wrong priority, resulting in dead lock situations ???
 123
 124       Build_Full_Name (Obj, Vnm);
 125
 126       --  First insert the Lock call before
 127
 128       Insert_Before_And_Analyze (Inode,
 129         Make_Procedure_Call_Statement (Loc,
 130           Name => New_Occurrence_Of (RTE (RE_Shared_Var_Lock), Loc),
 131           Parameter_Associations => New_List (
 132             Make_String_Literal (Loc, Vnm))));
 133
 134       --  Now, right after the Lock, insert a call to read the object
 135
 136       Insert_Before_And_Analyze (Inode,
 137         Make_Procedure_Call_Statement (Loc,
 138           Name => New_Occurrence_Of (Shared_Var_Read_Proc (Obj), Loc)));
 139
 140       --  Now insert the Unlock call after
 141
 142       Insert_After_And_Analyze (Inode,
 143         Make_Procedure_Call_Statement (Loc,
 144           Name => New_Occurrence_Of (RTE (RE_Shared_Var_Unlock), Loc),
 145           Parameter_Associations => New_List (
 146             Make_String_Literal (Loc, Vnm))));
 147
 148       --  Now for a procedure call, but not a function call, insert the
 149       --  call to write the object just before the unlock.
 150
 151       if Nkind (N) = N_Procedure_Call_Statement then
 152          Insert_After_And_Analyze (Inode,
 153            Make_Procedure_Call_Statement (Loc,
 154              Name => New_Occurrence_Of (Shared_Var_Assign_Proc (Obj), Loc)));
 155       end if;
 156
 157    end Add_Shared_Var_Lock_Procs;
 158
 159    ---------------------
 160    -- Add_Write_After --
 161    ---------------------
 162
 163    procedure Add_Write_After (N : Node_Id) is
 164       Loc : constant Source_Ptr := Sloc (N);
 165       Ent : constant Node_Id    := Entity (N);
 166
 167    begin
 168       if Present (Shared_Var_Assign_Proc (Ent)) then
 169          Insert_After_And_Analyze (Insert_Node,
 170            Make_Procedure_Call_Statement (Loc,
 171              Name =>
 172                New_Occurrence_Of (Shared_Var_Assign_Proc (Ent), Loc),
 173              Parameter_Associations => Empty_List));
 174       end if;
 175    end Add_Write_After;
 176
 177    ---------------------
 178    -- Build_Full_Name --
 179    ---------------------
 180
 181    procedure Build_Full_Name (E : Entity_Id; N : out String_Id) is
 182
 183       procedure Build_Name (E : Entity_Id);
 184       --  This is a recursive routine used to construct the fully qualified
 185       --  string name of the package corresponding to the shared variable.
 186
 187       ----------------
 188       -- Build_Name --
 189       ----------------
 190
 191       procedure Build_Name (E : Entity_Id) is
 192       begin
 193          if Scope (E) /= Standard_Standard then
 194             Build_Name (Scope (E));
 195             Store_String_Char ('.');
 196          end if;
 197
 198          Get_Decoded_Name_String (Chars (E));
 199          Store_String_Chars (Name_Buffer (1 .. Name_Len));
 200       end Build_Name;
 201
 202    --  Start of processing for Build_Full_Name
 203
 204    begin
 205       Start_String;
 206       Build_Name (E);
 207       N := End_String;
 208    end Build_Full_Name;
 209
 210    ------------------------------------
 211    -- Expand_Shared_Passive_Variable --
 212    ------------------------------------
 213
 214    procedure Expand_Shared_Passive_Variable (N : Node_Id) is
 215       Typ : constant Entity_Id := Etype (N);
 216
 217    begin
 218       --  Nothing to do for protected or limited objects
 219
 220       if Is_Limited_Type (Typ) or else Is_Concurrent_Type (Typ) then
 221          return;
 222
 223       --  If we are on the left hand side of an assignment, then we add
 224       --  the write call after the assignment.
 225
 226       elsif On_Lhs_Of_Assignment (N) then
 227          Add_Write_After (N);
 228
 229       --  If we are a parameter for an out or in out formal, then put
 230       --  the read before and the write after.
 231
 232       elsif Is_Out_Actual (N) then
 233          Add_Read_Before (N);
 234          Add_Write_After (N);
 235
 236       --  All other cases are simple reads
 237
 238       else
 239          Add_Read_Before (N);
 240       end if;
 241    end Expand_Shared_Passive_Variable;
 242
 243    -------------------
 244    -- Is_Out_Actual --
 245    -------------------
 246
 247    function Is_Out_Actual (N : Node_Id) return Boolean is
 248       Kind : Entity_Kind;
 249       Call : Node_Id;
 250
 251    begin
 252       Find_Actual_Mode (N, Kind, Call);
 253
 254       if Kind = E_Out_Parameter or else Kind = E_In_Out_Parameter then
 255          Insert_Node := Call;
 256          return True;
 257       else
 258          return False;
 259       end if;
 260    end Is_Out_Actual;
 261
 262    ---------------------------
 263    -- Make_Shared_Var_Procs --
 264    ---------------------------
 265
 266    function Make_Shared_Var_Procs (N : Node_Id) return Node_Id is
 267       Loc : constant Source_Ptr := Sloc (N);
 268       Ent : constant Entity_Id  := Defining_Identifier (N);
 269       Typ : constant Entity_Id  := Etype (Ent);
 270       Vnm : String_Id;
 271       Atr : Node_Id;
 272
 273       After : constant Node_Id := Next (N);
 274       --  Node located right after N originally (after insertion of the SV
 275       --  procs this node is right after the last inserted node).
 276
 277       Assign_Proc : constant Entity_Id :=
 278                       Make_Defining_Identifier (Loc,
 279                         Chars => New_External_Name (Chars (Ent), 'A'));
 280
 281       Read_Proc : constant Entity_Id :=
 282                     Make_Defining_Identifier (Loc,
 283                       Chars => New_External_Name (Chars (Ent), 'R'));
 284
 285       S : Entity_Id;
 286
 287    --  Start of processing for Make_Shared_Var_Procs
 288
 289    begin
 290       Build_Full_Name (Ent, Vnm);
 291
 292       --  We turn off Shared_Passive during construction and analysis of
 293       --  the assign and read routines, to avoid improper attempts to
 294       --  process the variable references within these procedures.
 295
 296       Set_Is_Shared_Passive (Ent, False);
 297
 298       --  Construct assignment routine
 299
 300       --    procedure VarA is
 301       --       S : Ada.Streams.Stream_IO.Stream_Access;
 302       --    begin
 303       --       S := Shared_Var_WOpen ("pkg.var");
 304       --       typ'Write (S, var);
 305       --       Shared_Var_Close (S);
 306       --    end VarA;
 307
 308       S   := Make_Defining_Identifier (Loc, Name_uS);
 309
 310       Atr :=
 311         Make_Attribute_Reference (Loc,
 312           Prefix => New_Occurrence_Of (Typ, Loc),
 313           Attribute_Name => Name_Write,
 314           Expressions => New_List (
 315             New_Reference_To (S, Loc),
 316             New_Occurrence_Of (Ent, Loc)));
 317
 318       Insert_After_And_Analyze (N,
 319         Make_Subprogram_Body (Loc,
 320           Specification =>
 321             Make_Procedure_Specification (Loc,
 322               Defining_Unit_Name => Assign_Proc),
 323
 324          --  S : Ada.Streams.Stream_IO.Stream_Access;
 325
 326           Declarations => New_List (
 327             Make_Object_Declaration (Loc,
 328               Defining_Identifier => S,
 329               Object_Definition =>
 330                 New_Occurrence_Of (RTE (RE_Stream_Access), Loc))),
 331
 332           Handled_Statement_Sequence =>
 333             Make_Handled_Sequence_Of_Statements (Loc,
 334               Statements => New_List (
 335
 336                --  S := Shared_Var_WOpen ("pkg.var");
 337
 338                 Make_Assignment_Statement (Loc,
 339                   Name => New_Reference_To (S, Loc),
 340                   Expression =>
 341                     Make_Function_Call (Loc,
 342                       Name =>
 343                         New_Occurrence_Of
 344                           (RTE (RE_Shared_Var_WOpen), Loc),
 345                       Parameter_Associations => New_List (
 346                         Make_String_Literal (Loc, Vnm)))),
 347
 348                 Atr,
 349
 350                --  Shared_Var_Close (S);
 351
 352                 Make_Procedure_Call_Statement (Loc,
 353                   Name =>
 354                     New_Occurrence_Of (RTE (RE_Shared_Var_Close), Loc),
 355                   Parameter_Associations =>
 356                     New_List (New_Reference_To (S, Loc)))))));
 357
 358       --  Construct read routine
 359
 360       --    procedure varR is
 361       --       S : Ada.Streams.Stream_IO.Stream_Access;
 362       --    begin
 363       --       S := Shared_Var_ROpen ("pkg.var");
 364       --       if S /= null then
 365       --          typ'Read (S, Var);
 366       --          Shared_Var_Close (S);
 367       --       end if;
 368       --    end varR;
 369
 370       S   := Make_Defining_Identifier (Loc, Name_uS);
 371
 372       Atr :=
 373         Make_Attribute_Reference (Loc,
 374           Prefix => New_Occurrence_Of (Typ, Loc),
 375           Attribute_Name => Name_Read,
 376           Expressions => New_List (
 377             New_Reference_To (S, Loc),
 378             New_Occurrence_Of (Ent, Loc)));
 379
 380       Insert_After_And_Analyze (N,
 381         Make_Subprogram_Body (Loc,
 382           Specification =>
 383             Make_Procedure_Specification (Loc,
 384               Defining_Unit_Name => Read_Proc),
 385
 386          --  S : Ada.Streams.Stream_IO.Stream_Access;
 387
 388           Declarations => New_List (
 389             Make_Object_Declaration (Loc,
 390               Defining_Identifier => S,
 391               Object_Definition =>
 392                 New_Occurrence_Of (RTE (RE_Stream_Access), Loc))),
 393
 394           Handled_Statement_Sequence =>
 395             Make_Handled_Sequence_Of_Statements (Loc,
 396               Statements => New_List (
 397
 398                --  S := Shared_Var_ROpen ("pkg.var");
 399
 400                 Make_Assignment_Statement (Loc,
 401                   Name => New_Reference_To (S, Loc),
 402                   Expression =>
 403                     Make_Function_Call (Loc,
 404                       Name =>
 405                         New_Occurrence_Of
 406                           (RTE (RE_Shared_Var_ROpen), Loc),
 407                       Parameter_Associations => New_List (
 408                         Make_String_Literal (Loc, Vnm)))),
 409
 410                --  if S /= null then
 411
 412                 Make_Implicit_If_Statement (N,
 413                   Condition =>
 414                     Make_Op_Ne (Loc,
 415                       Left_Opnd  => New_Reference_To (S, Loc),
 416                       Right_Opnd => Make_Null (Loc)),
 417
 418                    Then_Statements => New_List (
 419
 420                      --  typ'Read (S, Var);
 421
 422                      Atr,
 423
 424                      --  Shared_Var_Close (S);
 425
 426                      Make_Procedure_Call_Statement (Loc,
 427                        Name =>
 428                          New_Occurrence_Of
 429                            (RTE (RE_Shared_Var_Close), Loc),
 430                        Parameter_Associations =>
 431                          New_List (New_Reference_To (S, Loc)))))))));
 432
 433       Set_Is_Shared_Passive      (Ent, True);
 434       Set_Shared_Var_Assign_Proc (Ent, Assign_Proc);
 435       Set_Shared_Var_Read_Proc   (Ent, Read_Proc);
 436
 437       --  Return last node before After
 438
 439       declare
 440          Nod : Node_Id := Next (N);
 441
 442       begin
 443          while Next (Nod) /= After loop
 444             Nod := Next (Nod);
 445          end loop;
 446
 447          return Nod;
 448       end;
 449    end Make_Shared_Var_Procs;
 450
 451    --------------------------
 452    -- On_Lhs_Of_Assignment --
 453    --------------------------
 454
 455    function On_Lhs_Of_Assignment (N : Node_Id) return Boolean is
 456       P : constant Node_Id := Parent (N);
 457
 458    begin
 459       if Nkind (P) = N_Assignment_Statement then
 460          if N = Name (P) then
 461             Insert_Node := P;
 462             return True;
 463          else
 464             return False;
 465          end if;
 466
 467       elsif (Nkind (P) = N_Indexed_Component
 468                or else
 469              Nkind (P) = N_Selected_Component)
 470         and then N = Prefix (P)
 471       then
 472          return On_Lhs_Of_Assignment (P);
 473
 474       else
 475          return False;
 476       end if;
 477    end On_Lhs_Of_Assignment;
 478
 479 end Exp_Smem;