gcc/ada/sem_dim.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              S E M _ D I M                               --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2011-2016, 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 Aspects;  use Aspects;
  27 with Atree;    use Atree;
  28 with Einfo;    use Einfo;
  29 with Errout;   use Errout;
  30 with Exp_Util; use Exp_Util;
  31 with Lib;      use Lib;
  32 with Namet;    use Namet;
  33 with Nlists;   use Nlists;
  34 with Nmake;    use Nmake;
  35 with Opt;      use Opt;
  36 with Rtsfind;  use Rtsfind;
  37 with Sem;      use Sem;
  38 with Sem_Eval; use Sem_Eval;
  39 with Sem_Res;  use Sem_Res;
  40 with Sem_Util; use Sem_Util;
  41 with Sinfo;    use Sinfo;
  42 with Sinput;   use Sinput;
  43 with Snames;   use Snames;
  44 with Stand;    use Stand;
  45 with Stringt;  use Stringt;
  46 with Table;
  47 with Tbuild;   use Tbuild;
  48 with Uintp;    use Uintp;
  49 with Urealp;   use Urealp;
  50
  51 with GNAT.HTable;
  52
  53 package body Sem_Dim is
  54
  55    -------------------------
  56    -- Rational Arithmetic --
  57    -------------------------
  58
  59    type Whole is new Int;
  60    subtype Positive_Whole is Whole range 1 .. Whole'Last;
  61
  62    type Rational is record
  63       Numerator   : Whole;
  64       Denominator : Positive_Whole;
  65    end record;
  66
  67    Zero : constant Rational := Rational'(Numerator =>   0,
  68                                          Denominator => 1);
  69
  70    No_Rational : constant Rational := Rational'(Numerator =>   0,
  71                                                 Denominator => 2);
  72    --  Used to indicate an expression that cannot be interpreted as a rational
  73    --  Returned value of the Create_Rational_From routine when parameter Expr
  74    --  is not a static representation of a rational.
  75
  76    --  Rational constructors
  77
  78    function "+" (Right : Whole) return Rational;
  79    function GCD (Left, Right : Whole) return Int;
  80    function Reduce (X : Rational) return Rational;
  81
  82    --  Unary operator for Rational
  83
  84    function "-" (Right : Rational) return Rational;
  85    function "abs" (Right : Rational) return Rational;
  86
  87    --  Rational operations for Rationals
  88
  89    function "+" (Left, Right : Rational) return Rational;
  90    function "-" (Left, Right : Rational) return Rational;
  91    function "*" (Left, Right : Rational) return Rational;
  92    function "/" (Left, Right : Rational) return Rational;
  93
  94    ------------------
  95    -- System Types --
  96    ------------------
  97
  98    Max_Number_Of_Dimensions : constant := 7;
  99    --  Maximum number of dimensions in a dimension system
 100
 101    High_Position_Bound : constant := Max_Number_Of_Dimensions;
 102    Invalid_Position    : constant := 0;
 103    Low_Position_Bound  : constant := 1;
 104
 105    subtype Dimension_Position is
 106      Nat range Invalid_Position .. High_Position_Bound;
 107
 108    type Name_Array is
 109      array (Dimension_Position range
 110               Low_Position_Bound .. High_Position_Bound) of Name_Id;
 111    --  Store the names of all units within a system
 112
 113    No_Names : constant Name_Array := (others => No_Name);
 114
 115    type Symbol_Array is
 116      array (Dimension_Position range
 117               Low_Position_Bound ..  High_Position_Bound) of String_Id;
 118    --  Store the symbols of all units within a system
 119
 120    No_Symbols : constant Symbol_Array := (others => No_String);
 121
 122    --  The following record should be documented field by field
 123
 124    type System_Type is record
 125       Type_Decl    : Node_Id;
 126       Unit_Names   : Name_Array;
 127       Unit_Symbols : Symbol_Array;
 128       Dim_Symbols  : Symbol_Array;
 129       Count        : Dimension_Position;
 130    end record;
 131
 132    Null_System : constant System_Type :=
 133                    (Empty, No_Names, No_Symbols, No_Symbols, Invalid_Position);
 134
 135    subtype System_Id is Nat;
 136
 137    --  The following table maps types to systems
 138
 139    package System_Table is new Table.Table (
 140      Table_Component_Type => System_Type,
 141      Table_Index_Type     => System_Id,
 142      Table_Low_Bound      => 1,
 143      Table_Initial        => 5,
 144      Table_Increment      => 5,
 145      Table_Name           => "System_Table");
 146
 147    --------------------
 148    -- Dimension Type --
 149    --------------------
 150
 151    type Dimension_Type is
 152      array (Dimension_Position range
 153               Low_Position_Bound ..  High_Position_Bound) of Rational;
 154
 155    Null_Dimension : constant Dimension_Type := (others => Zero);
 156
 157    type Dimension_Table_Range is range 0 .. 510;
 158    function Dimension_Table_Hash (Key : Node_Id) return Dimension_Table_Range;
 159
 160    --  The following table associates nodes with dimensions
 161
 162    package Dimension_Table is new
 163      GNAT.HTable.Simple_HTable
 164        (Header_Num => Dimension_Table_Range,
 165         Element    => Dimension_Type,
 166         No_Element => Null_Dimension,
 167         Key        => Node_Id,
 168         Hash       => Dimension_Table_Hash,
 169         Equal      => "=");
 170
 171    ------------------
 172    -- Symbol Types --
 173    ------------------
 174
 175    type Symbol_Table_Range is range 0 .. 510;
 176    function Symbol_Table_Hash (Key : Entity_Id) return Symbol_Table_Range;
 177
 178    --  Each subtype with a dimension has a symbolic representation of the
 179    --  related unit. This table establishes a relation between the subtype
 180    --  and the symbol.
 181
 182    package Symbol_Table is new
 183      GNAT.HTable.Simple_HTable
 184        (Header_Num => Symbol_Table_Range,
 185         Element    => String_Id,
 186         No_Element => No_String,
 187         Key        => Entity_Id,
 188         Hash       => Symbol_Table_Hash,
 189         Equal      => "=");
 190
 191    --  The following array enumerates all contexts which may contain or
 192    --  produce a dimension.
 193
 194    OK_For_Dimension : constant array (Node_Kind) of Boolean :=
 195      (N_Attribute_Reference       => True,
 196       N_Expanded_Name             => True,
 197       N_Explicit_Dereference      => True,
 198       N_Defining_Identifier       => True,
 199       N_Function_Call             => True,
 200       N_Identifier                => True,
 201       N_Indexed_Component         => True,
 202       N_Integer_Literal           => True,
 203       N_Op_Abs                    => True,
 204       N_Op_Add                    => True,
 205       N_Op_Divide                 => True,
 206       N_Op_Expon                  => True,
 207       N_Op_Minus                  => True,
 208       N_Op_Mod                    => True,
 209       N_Op_Multiply               => True,
 210       N_Op_Plus                   => True,
 211       N_Op_Rem                    => True,
 212       N_Op_Subtract               => True,
 213       N_Qualified_Expression      => True,
 214       N_Real_Literal              => True,
 215       N_Selected_Component        => True,
 216       N_Slice                     => True,
 217       N_Type_Conversion           => True,
 218       N_Unchecked_Type_Conversion => True,
 219
 220       others                      => False);
 221
 222    -----------------------
 223    -- Local Subprograms --
 224    -----------------------
 225
 226    procedure Analyze_Dimension_Assignment_Statement (N : Node_Id);
 227    --  Subroutine of Analyze_Dimension for assignment statement. Check that the
 228    --  dimensions of the left-hand side and the right-hand side of N match.
 229
 230    procedure Analyze_Dimension_Binary_Op (N : Node_Id);
 231    --  Subroutine of Analyze_Dimension for binary operators. Check the
 232    --  dimensions of the right and the left operand permit the operation.
 233    --  Then, evaluate the resulting dimensions for each binary operator.
 234
 235    procedure Analyze_Dimension_Component_Declaration (N : Node_Id);
 236    --  Subroutine of Analyze_Dimension for component declaration. Check that
 237    --  the dimensions of the type of N and of the expression match.
 238
 239    procedure Analyze_Dimension_Extended_Return_Statement (N : Node_Id);
 240    --  Subroutine of Analyze_Dimension for extended return statement. Check
 241    --  that the dimensions of the returned type and of the returned object
 242    --  match.
 243
 244    procedure Analyze_Dimension_Has_Etype (N : Node_Id);
 245    --  Subroutine of Analyze_Dimension for a subset of N_Has_Etype denoted by
 246    --  the list below:
 247    --    N_Attribute_Reference
 248    --    N_Identifier
 249    --    N_Indexed_Component
 250    --    N_Qualified_Expression
 251    --    N_Selected_Component
 252    --    N_Slice
 253    --    N_Type_Conversion
 254    --    N_Unchecked_Type_Conversion
 255
 256    procedure Analyze_Dimension_Number_Declaration (N : Node_Id);
 257    --  Procedure to analyze dimension of expression in a number declaration.
 258    --  This allows a named number to have nontrivial dimensions, while by
 259    --  default a named number is dimensionless.
 260
 261    procedure Analyze_Dimension_Object_Declaration (N : Node_Id);
 262    --  Subroutine of Analyze_Dimension for object declaration. Check that
 263    --  the dimensions of the object type and the dimensions of the expression
 264    --  (if expression is present) match. Note that when the expression is
 265    --  a literal, no error is returned. This special case allows object
 266    --  declaration such as: m : constant Length := 1.0;
 267
 268    procedure Analyze_Dimension_Object_Renaming_Declaration (N : Node_Id);
 269    --  Subroutine of Analyze_Dimension for object renaming declaration. Check
 270    --  the dimensions of the type and of the renamed object name of N match.
 271
 272    procedure Analyze_Dimension_Simple_Return_Statement (N : Node_Id);
 273    --  Subroutine of Analyze_Dimension for simple return statement
 274    --  Check that the dimensions of the returned type and of the returned
 275    --  expression match.
 276
 277    procedure Analyze_Dimension_Subtype_Declaration (N : Node_Id);
 278    --  Subroutine of Analyze_Dimension for subtype declaration. Propagate the
 279    --  dimensions from the parent type to the identifier of N. Note that if
 280    --  both the identifier and the parent type of N are not dimensionless,
 281    --  return an error.
 282
 283    procedure Analyze_Dimension_Unary_Op (N : Node_Id);
 284    --  Subroutine of Analyze_Dimension for unary operators. For Plus, Minus and
 285    --  Abs operators, propagate the dimensions from the operand to N.
 286
 287    function Create_Rational_From
 288      (Expr     : Node_Id;
 289       Complain : Boolean) return Rational;
 290    --  Given an arbitrary expression Expr, return a valid rational if Expr can
 291    --  be interpreted as a rational. Otherwise return No_Rational and also an
 292    --  error message if Complain is set to True.
 293
 294    function Dimensions_Of (N : Node_Id) return Dimension_Type;
 295    --  Return the dimension vector of node N
 296
 297    function Dimensions_Msg_Of
 298       (N                  : Node_Id;
 299        Description_Needed : Boolean := False) return String;
 300    --  Given a node N, return the dimension symbols of N, preceded by "has
 301    --  dimension" if Description_Needed. if N is dimensionless, return "'[']",
 302    --  or "is dimensionless" if Description_Needed.
 303
 304    procedure Dim_Warning_For_Numeric_Literal (N : Node_Id; Typ : Entity_Id);
 305    --  Issue a warning on the given numeric literal N to indicate that the
 306    --  compiler made the assumption that the literal is not dimensionless
 307    --  but has the dimension of Typ.
 308
 309    procedure Eval_Op_Expon_With_Rational_Exponent
 310      (N              : Node_Id;
 311       Exponent_Value : Rational);
 312    --  Evaluate the exponent it is a rational and the operand has a dimension
 313
 314    function Exists (Dim : Dimension_Type) return Boolean;
 315    --  Returns True iff Dim does not denote the null dimension
 316
 317    function Exists (Str : String_Id) return Boolean;
 318    --  Returns True iff Str does not denote No_String
 319
 320    function Exists (Sys : System_Type) return Boolean;
 321    --  Returns True iff Sys does not denote the null system
 322
 323    function From_Dim_To_Str_Of_Dim_Symbols
 324      (Dims         : Dimension_Type;
 325       System       : System_Type;
 326       In_Error_Msg : Boolean := False) return String_Id;
 327    --  Given a dimension vector and a dimension system, return the proper
 328    --  string of dimension symbols. If In_Error_Msg is True (i.e. the String_Id
 329    --  will be used to issue an error message) then this routine has a special
 330    --  handling for the insertion characters * or [ which must be preceded by
 331    --  a quote ' to be placed literally into the message.
 332
 333    function From_Dim_To_Str_Of_Unit_Symbols
 334      (Dims   : Dimension_Type;
 335       System : System_Type) return String_Id;
 336    --  Given a dimension vector and a dimension system, return the proper
 337    --  string of unit symbols.
 338
 339    function Is_Dim_IO_Package_Entity (E : Entity_Id) return Boolean;
 340    --  Return True if E is the package entity of System.Dim.Float_IO or
 341    --  System.Dim.Integer_IO.
 342
 343    function Is_Invalid (Position : Dimension_Position) return Boolean;
 344    --  Return True if Pos denotes the invalid position
 345
 346    procedure Move_Dimensions (From : Node_Id; To : Node_Id);
 347    --  Copy dimension vector of From to To and delete dimension vector of From
 348
 349    procedure Remove_Dimensions (N : Node_Id);
 350    --  Remove the dimension vector of node N
 351
 352    procedure Set_Dimensions (N : Node_Id; Val : Dimension_Type);
 353    --  Associate a dimension vector with a node
 354
 355    procedure Set_Symbol (E : Entity_Id; Val : String_Id);
 356    --  Associate a symbol representation of a dimension vector with a subtype
 357
 358    function String_From_Numeric_Literal (N : Node_Id) return String_Id;
 359    --  Return the string that corresponds to the numeric litteral N as it
 360    --  appears in the source.
 361
 362    function Symbol_Of (E : Entity_Id) return String_Id;
 363    --  E denotes a subtype with a dimension. Return the symbol representation
 364    --  of the dimension vector.
 365
 366    function System_Of (E : Entity_Id) return System_Type;
 367    --  E denotes a type, return associated system of the type if it has one
 368
 369    ---------
 370    -- "+" --
 371    ---------
 372
 373    function "+" (Right : Whole) return Rational is
 374    begin
 375       return Rational'(Numerator => Right, Denominator => 1);
 376    end "+";
 377
 378    function "+" (Left, Right : Rational) return Rational is
 379       R : constant Rational :=
 380             Rational'(Numerator   =>  Left.Numerator   * Right.Denominator +
 381                                       Left.Denominator * Right.Numerator,
 382                       Denominator => Left.Denominator  * Right.Denominator);
 383    begin
 384       return Reduce (R);
 385    end "+";
 386
 387    ---------
 388    -- "-" --
 389    ---------
 390
 391    function "-" (Right : Rational) return Rational is
 392    begin
 393       return Rational'(Numerator   => -Right.Numerator,
 394                        Denominator => Right.Denominator);
 395    end "-";
 396
 397    function "-" (Left, Right : Rational) return Rational is
 398       R : constant Rational :=
 399             Rational'(Numerator   => Left.Numerator   * Right.Denominator -
 400                                      Left.Denominator * Right.Numerator,
 401                       Denominator => Left.Denominator * Right.Denominator);
 402
 403    begin
 404       return Reduce (R);
 405    end "-";
 406
 407    ---------
 408    -- "*" --
 409    ---------
 410
 411    function "*" (Left, Right : Rational) return Rational is
 412       R : constant Rational :=
 413             Rational'(Numerator   => Left.Numerator   * Right.Numerator,
 414                       Denominator => Left.Denominator * Right.Denominator);
 415    begin
 416       return Reduce (R);
 417    end "*";
 418
 419    ---------
 420    -- "/" --
 421    ---------
 422
 423    function "/" (Left, Right : Rational) return Rational is
 424       R : constant Rational := abs Right;
 425       L : Rational := Left;
 426
 427    begin
 428       if Right.Numerator < 0 then
 429          L.Numerator := Whole (-Integer (L.Numerator));
 430       end if;
 431
 432       return Reduce (Rational'(Numerator   => L.Numerator   * R.Denominator,
 433                                Denominator => L.Denominator * R.Numerator));
 434    end "/";
 435
 436    -----------
 437    -- "abs" --
 438    -----------
 439
 440    function "abs" (Right : Rational) return Rational is
 441    begin
 442       return Rational'(Numerator   => abs Right.Numerator,
 443                        Denominator => Right.Denominator);
 444    end "abs";
 445
 446    ------------------------------
 447    -- Analyze_Aspect_Dimension --
 448    ------------------------------
 449
 450    --  with Dimension =>
 451    --    ([Symbol =>] SYMBOL, DIMENSION_VALUE {, DIMENSION_Value})
 452    --
 453    --  SYMBOL ::= STRING_LITERAL | CHARACTER_LITERAL
 454
 455    --  DIMENSION_VALUE ::=
 456    --    RATIONAL
 457    --  | others               => RATIONAL
 458    --  | DISCRETE_CHOICE_LIST => RATIONAL
 459
 460    --  RATIONAL ::= [-] NUMERIC_LITERAL [/ NUMERIC_LITERAL]
 461
 462    --  Note that when the dimensioned type is an integer type, then any
 463    --  dimension value must be an integer literal.
 464
 465    procedure Analyze_Aspect_Dimension
 466      (N    : Node_Id;
 467       Id   : Entity_Id;
 468       Aggr : Node_Id)
 469    is
 470       Def_Id : constant Entity_Id := Defining_Identifier (N);
 471
 472       Processed : array (Dimension_Type'Range) of Boolean := (others => False);
 473       --  This array is used when processing ranges or Others_Choice as part of
 474       --  the dimension aggregate.
 475
 476       Dimensions : Dimension_Type := Null_Dimension;
 477
 478       procedure Extract_Power
 479         (Expr     : Node_Id;
 480          Position : Dimension_Position);
 481       --  Given an expression with denotes a rational number, read the number
 482       --  and associate it with Position in Dimensions.
 483
 484       function Position_In_System
 485         (Id     : Node_Id;
 486          System : System_Type) return Dimension_Position;
 487       --  Given an identifier which denotes a dimension, return the position of
 488       --  that dimension within System.
 489
 490       -------------------
 491       -- Extract_Power --
 492       -------------------
 493
 494       procedure Extract_Power
 495         (Expr     : Node_Id;
 496          Position : Dimension_Position)
 497       is
 498       begin
 499          --  Integer case
 500
 501          if Is_Integer_Type (Def_Id) then
 502
 503             --  Dimension value must be an integer literal
 504
 505             if Nkind (Expr) = N_Integer_Literal then
 506                Dimensions (Position) := +Whole (UI_To_Int (Intval (Expr)));
 507             else
 508                Error_Msg_N ("integer literal expected", Expr);
 509             end if;
 510
 511          --  Float case
 512
 513          else
 514             Dimensions (Position) := Create_Rational_From (Expr, True);
 515          end if;
 516
 517          Processed (Position) := True;
 518       end Extract_Power;
 519
 520       ------------------------
 521       -- Position_In_System --
 522       ------------------------
 523
 524       function Position_In_System
 525         (Id     : Node_Id;
 526          System : System_Type) return Dimension_Position
 527       is
 528          Dimension_Name : constant Name_Id := Chars (Id);
 529
 530       begin
 531          for Position in System.Unit_Names'Range loop
 532             if Dimension_Name = System.Unit_Names (Position) then
 533                return Position;
 534             end if;
 535          end loop;
 536
 537          return Invalid_Position;
 538       end Position_In_System;
 539
 540       --  Local variables
 541
 542       Assoc          : Node_Id;
 543       Choice         : Node_Id;
 544       Expr           : Node_Id;
 545       Num_Choices    : Nat := 0;
 546       Num_Dimensions : Nat := 0;
 547       Others_Seen    : Boolean := False;
 548       Position       : Nat := 0;
 549       Sub_Ind        : Node_Id;
 550       Symbol         : String_Id := No_String;
 551       Symbol_Expr    : Node_Id;
 552       System         : System_Type;
 553       Typ            : Entity_Id;
 554
 555       Errors_Count : Nat;
 556       --  Errors_Count is a count of errors detected by the compiler so far
 557       --  just before the extraction of symbol, names and values in the
 558       --  aggregate (Step 2).
 559       --
 560       --  At the end of the analysis, there is a check to verify that this
 561       --  count equals to Serious_Errors_Detected i.e. no erros have been
 562       --  encountered during the process. Otherwise the Dimension_Table is
 563       --  not filled.
 564
 565    --  Start of processing for Analyze_Aspect_Dimension
 566
 567    begin
 568       --  STEP 1: Legality of aspect
 569
 570       if Nkind (N) /= N_Subtype_Declaration then
 571          Error_Msg_NE ("aspect& must apply to subtype declaration", N, Id);
 572          return;
 573       end if;
 574
 575       Sub_Ind := Subtype_Indication (N);
 576       Typ := Etype (Sub_Ind);
 577       System := System_Of (Typ);
 578
 579       if Nkind (Sub_Ind) = N_Subtype_Indication then
 580          Error_Msg_NE
 581            ("constraint not allowed with aspect&", Constraint (Sub_Ind), Id);
 582          return;
 583       end if;
 584
 585       --  The dimension declarations are useless if the parent type does not
 586       --  declare a valid system.
 587
 588       if not Exists (System) then
 589          Error_Msg_NE
 590            ("parent type of& lacks dimension system", Sub_Ind, Def_Id);
 591          return;
 592       end if;
 593
 594       if Nkind (Aggr) /= N_Aggregate then
 595          Error_Msg_N ("aggregate expected", Aggr);
 596          return;
 597       end if;
 598
 599       --  STEP 2: Symbol, Names and values extraction
 600
 601       --  Get the number of errors detected by the compiler so far
 602
 603       Errors_Count := Serious_Errors_Detected;
 604
 605       --  STEP 2a: Symbol extraction
 606
 607       --  The first entry in the aggregate may be the symbolic representation
 608       --  of the quantity.
 609
 610       --  Positional symbol argument
 611
 612       Symbol_Expr := First (Expressions (Aggr));
 613
 614       --  Named symbol argument
 615
 616       if No (Symbol_Expr)
 617         or else not Nkind_In (Symbol_Expr, N_Character_Literal,
 618                                            N_String_Literal)
 619       then
 620          Symbol_Expr := Empty;
 621
 622          --  Component associations present
 623
 624          if Present (Component_Associations (Aggr)) then
 625             Assoc  := First (Component_Associations (Aggr));
 626             Choice := First (Choices (Assoc));
 627
 628             if No (Next (Choice)) and then Nkind (Choice) = N_Identifier then
 629
 630                --  Symbol component association is present
 631
 632                if Chars (Choice) = Name_Symbol then
 633                   Num_Choices := Num_Choices + 1;
 634                   Symbol_Expr := Expression (Assoc);
 635
 636                   --  Verify symbol expression is a string or a character
 637
 638                   if not Nkind_In (Symbol_Expr, N_Character_Literal,
 639                                                 N_String_Literal)
 640                   then
 641                      Symbol_Expr := Empty;
 642                      Error_Msg_N
 643                        ("symbol expression must be character or string",
 644                         Symbol_Expr);
 645                   end if;
 646
 647                --  Special error if no Symbol choice but expression is string
 648                --  or character.
 649
 650                elsif Nkind_In (Expression (Assoc), N_Character_Literal,
 651                                                    N_String_Literal)
 652                then
 653                   Num_Choices := Num_Choices + 1;
 654                   Error_Msg_N
 655                     ("optional component Symbol expected, found&", Choice);
 656                end if;
 657             end if;
 658          end if;
 659       end if;
 660
 661       --  STEP 2b: Names and values extraction
 662
 663       --  Positional elements
 664
 665       Expr := First (Expressions (Aggr));
 666
 667       --  Skip the symbol expression when present
 668
 669       if Present (Symbol_Expr) and then Num_Choices = 0 then
 670          Expr := Next (Expr);
 671       end if;
 672
 673       Position := Low_Position_Bound;
 674       while Present (Expr) loop
 675          if Position > High_Position_Bound then
 676             Error_Msg_N
 677               ("type& has more dimensions than system allows", Def_Id);
 678             exit;
 679          end if;
 680
 681          Extract_Power (Expr, Position);
 682
 683          Position := Position + 1;
 684          Num_Dimensions := Num_Dimensions + 1;
 685
 686          Next (Expr);
 687       end loop;
 688
 689       --  Named elements
 690
 691       Assoc := First (Component_Associations (Aggr));
 692
 693       --  Skip the symbol association when present
 694
 695       if Num_Choices = 1 then
 696          Next (Assoc);
 697       end if;
 698
 699       while Present (Assoc) loop
 700          Expr := Expression (Assoc);
 701
 702          Choice := First (Choices (Assoc));
 703          while Present (Choice) loop
 704
 705             --  Identifier case: NAME => EXPRESSION
 706
 707             if Nkind (Choice) = N_Identifier then
 708                Position := Position_In_System (Choice, System);
 709
 710                if Is_Invalid (Position) then
 711                   Error_Msg_N ("dimension name& not part of system", Choice);
 712                else
 713                   Extract_Power (Expr, Position);
 714                end if;
 715
 716             --  Range case: NAME .. NAME => EXPRESSION
 717
 718             elsif Nkind (Choice) = N_Range then
 719                declare
 720                   Low      : constant Node_Id := Low_Bound (Choice);
 721                   High     : constant Node_Id := High_Bound (Choice);
 722                   Low_Pos  : Dimension_Position;
 723                   High_Pos : Dimension_Position;
 724
 725                begin
 726                   if Nkind (Low) /= N_Identifier then
 727                      Error_Msg_N ("bound must denote a dimension name", Low);
 728
 729                   elsif Nkind (High) /= N_Identifier then
 730                      Error_Msg_N ("bound must denote a dimension name", High);
 731
 732                   else
 733                      Low_Pos  := Position_In_System (Low, System);
 734                      High_Pos := Position_In_System (High, System);
 735
 736                      if Is_Invalid (Low_Pos) then
 737                         Error_Msg_N ("dimension name& not part of system",
 738                                      Low);
 739
 740                      elsif Is_Invalid (High_Pos) then
 741                         Error_Msg_N ("dimension name& not part of system",
 742                                      High);
 743
 744                      elsif Low_Pos > High_Pos then
 745                         Error_Msg_N ("expected low to high range", Choice);
 746
 747                      else
 748                         for Position in Low_Pos .. High_Pos loop
 749                            Extract_Power (Expr, Position);
 750                         end loop;
 751                      end if;
 752                   end if;
 753                end;
 754
 755             --  Others case: OTHERS => EXPRESSION
 756
 757             elsif Nkind (Choice) = N_Others_Choice then
 758                if Present (Next (Choice)) or else Present (Prev (Choice)) then
 759                   Error_Msg_N
 760                     ("OTHERS must appear alone in a choice list", Choice);
 761
 762                elsif Present (Next (Assoc)) then
 763                   Error_Msg_N
 764                     ("OTHERS must appear last in an aggregate", Choice);
 765
 766                elsif Others_Seen then
 767                   Error_Msg_N ("multiple OTHERS not allowed", Choice);
 768
 769                else
 770                   --  Fill the non-processed dimensions with the default value
 771                   --  supplied by others.
 772
 773                   for Position in Processed'Range loop
 774                      if not Processed (Position) then
 775                         Extract_Power (Expr, Position);
 776                      end if;
 777                   end loop;
 778                end if;
 779
 780                Others_Seen := True;
 781
 782             --  All other cases are illegal declarations of dimension names
 783
 784             else
 785                Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
 786             end if;
 787
 788             Num_Choices := Num_Choices + 1;
 789             Next (Choice);
 790          end loop;
 791
 792          Num_Dimensions := Num_Dimensions + 1;
 793          Next (Assoc);
 794       end loop;
 795
 796       --  STEP 3: Consistency of system and dimensions
 797
 798       if Present (First (Expressions (Aggr)))
 799         and then (First (Expressions (Aggr)) /= Symbol_Expr
 800                    or else Present (Next (Symbol_Expr)))
 801         and then (Num_Choices > 1
 802                    or else (Num_Choices = 1 and then not Others_Seen))
 803       then
 804          Error_Msg_N
 805            ("named associations cannot follow positional associations", Aggr);
 806       end if;
 807
 808       if Num_Dimensions > System.Count then
 809          Error_Msg_N ("type& has more dimensions than system allows", Def_Id);
 810
 811       elsif Num_Dimensions < System.Count and then not Others_Seen then
 812          Error_Msg_N ("type& has less dimensions than system allows", Def_Id);
 813       end if;
 814
 815       --  STEP 4: Dimension symbol extraction
 816
 817       if Present (Symbol_Expr) then
 818          if Nkind (Symbol_Expr) = N_Character_Literal then
 819             Start_String;
 820             Store_String_Char (UI_To_CC (Char_Literal_Value (Symbol_Expr)));
 821             Symbol := End_String;
 822
 823          else
 824             Symbol := Strval (Symbol_Expr);
 825          end if;
 826
 827          if String_Length (Symbol) = 0 then
 828             Error_Msg_N ("empty string not allowed here", Symbol_Expr);
 829          end if;
 830       end if;
 831
 832       --  STEP 5: Storage of extracted values
 833
 834       --  Check that no errors have been detected during the analysis
 835
 836       if Errors_Count = Serious_Errors_Detected then
 837
 838          --  Check for useless declaration
 839
 840          if Symbol = No_String and then not Exists (Dimensions) then
 841             Error_Msg_N ("useless dimension declaration", Aggr);
 842          end if;
 843
 844          if Symbol /= No_String then
 845             Set_Symbol (Def_Id, Symbol);
 846          end if;
 847
 848          if Exists (Dimensions) then
 849             Set_Dimensions (Def_Id, Dimensions);
 850          end if;
 851       end if;
 852    end Analyze_Aspect_Dimension;
 853
 854    -------------------------------------
 855    -- Analyze_Aspect_Dimension_System --
 856    -------------------------------------
 857
 858    --  with Dimension_System => (DIMENSION {, DIMENSION});
 859
 860    --  DIMENSION ::= (
 861    --    [Unit_Name   =>] IDENTIFIER,
 862    --    [Unit_Symbol =>] SYMBOL,
 863    --    [Dim_Symbol  =>] SYMBOL)
 864
 865    procedure Analyze_Aspect_Dimension_System
 866      (N    : Node_Id;
 867       Id   : Entity_Id;
 868       Aggr : Node_Id)
 869    is
 870       function Is_Derived_Numeric_Type (N : Node_Id) return Boolean;
 871       --  Determine whether type declaration N denotes a numeric derived type
 872
 873       -------------------------------
 874       -- Is_Derived_Numeric_Type --
 875       -------------------------------
 876
 877       function Is_Derived_Numeric_Type (N : Node_Id) return Boolean is
 878       begin
 879          return
 880            Nkind (N) = N_Full_Type_Declaration
 881              and then Nkind (Type_Definition (N)) = N_Derived_Type_Definition
 882              and then Is_Numeric_Type
 883                         (Entity (Subtype_Indication (Type_Definition (N))));
 884       end Is_Derived_Numeric_Type;
 885
 886       --  Local variables
 887
 888       Assoc        : Node_Id;
 889       Choice       : Node_Id;
 890       Dim_Aggr     : Node_Id;
 891       Dim_Symbol   : Node_Id;
 892       Dim_Symbols  : Symbol_Array := No_Symbols;
 893       Dim_System   : System_Type  := Null_System;
 894       Position     : Nat := 0;
 895       Unit_Name    : Node_Id;
 896       Unit_Names   : Name_Array   := No_Names;
 897       Unit_Symbol  : Node_Id;
 898       Unit_Symbols : Symbol_Array := No_Symbols;
 899
 900       Errors_Count : Nat;
 901       --  Errors_Count is a count of errors detected by the compiler so far
 902       --  just before the extraction of names and symbols in the aggregate
 903       --  (Step 3).
 904       --
 905       --  At the end of the analysis, there is a check to verify that this
 906       --  count equals Serious_Errors_Detected i.e. no errors have been
 907       --  encountered during the process. Otherwise the System_Table is
 908       --  not filled.
 909
 910    --  Start of processing for Analyze_Aspect_Dimension_System
 911
 912    begin
 913       --  STEP 1: Legality of aspect
 914
 915       if not Is_Derived_Numeric_Type (N) then
 916          Error_Msg_NE
 917            ("aspect& must apply to numeric derived type declaration", N, Id);
 918          return;
 919       end if;
 920
 921       if Nkind (Aggr) /= N_Aggregate then
 922          Error_Msg_N ("aggregate expected", Aggr);
 923          return;
 924       end if;
 925
 926       --  STEP 2: Structural verification of the dimension aggregate
 927
 928       if Present (Component_Associations (Aggr)) then
 929          Error_Msg_N ("expected positional aggregate", Aggr);
 930          return;
 931       end if;
 932
 933       --  STEP 3: Name and Symbol extraction
 934
 935       Dim_Aggr     := First (Expressions (Aggr));
 936       Errors_Count := Serious_Errors_Detected;
 937       while Present (Dim_Aggr) loop
 938          Position := Position + 1;
 939
 940          if Position > High_Position_Bound then
 941             Error_Msg_N ("too many dimensions in system", Aggr);
 942             exit;
 943          end if;
 944
 945          if Nkind (Dim_Aggr) /= N_Aggregate then
 946             Error_Msg_N ("aggregate expected", Dim_Aggr);
 947
 948          else
 949             if Present (Component_Associations (Dim_Aggr))
 950               and then Present (Expressions (Dim_Aggr))
 951             then
 952                Error_Msg_N
 953                  ("mixed positional/named aggregate not allowed here",
 954                   Dim_Aggr);
 955
 956             --  Verify each dimension aggregate has three arguments
 957
 958             elsif List_Length (Component_Associations (Dim_Aggr)) /= 3
 959               and then List_Length (Expressions (Dim_Aggr)) /= 3
 960             then
 961                Error_Msg_N
 962                  ("three components expected in aggregate", Dim_Aggr);
 963
 964             else
 965                --  Named dimension aggregate
 966
 967                if Present (Component_Associations (Dim_Aggr)) then
 968
 969                   --  Check first argument denotes the unit name
 970
 971                   Assoc     := First (Component_Associations (Dim_Aggr));
 972                   Choice    := First (Choices (Assoc));
 973                   Unit_Name := Expression (Assoc);
 974
 975                   if Present (Next (Choice))
 976                     or else Nkind (Choice) /= N_Identifier
 977                   then
 978                      Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
 979
 980                   elsif Chars (Choice) /= Name_Unit_Name then
 981                      Error_Msg_N ("expected Unit_Name, found&", Choice);
 982                   end if;
 983
 984                   --  Check the second argument denotes the unit symbol
 985
 986                   Next (Assoc);
 987                   Choice      := First (Choices (Assoc));
 988                   Unit_Symbol := Expression (Assoc);
 989
 990                   if Present (Next (Choice))
 991                     or else Nkind (Choice) /= N_Identifier
 992                   then
 993                      Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
 994
 995                   elsif Chars (Choice) /= Name_Unit_Symbol then
 996                      Error_Msg_N ("expected Unit_Symbol, found&", Choice);
 997                   end if;
 998
 999                   --  Check the third argument denotes the dimension symbol
1000
1001                   Next (Assoc);
1002                   Choice     := First (Choices (Assoc));
1003                   Dim_Symbol := Expression (Assoc);
1004
1005                   if Present (Next (Choice))
1006                     or else Nkind (Choice) /= N_Identifier
1007                   then
1008                      Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
1009                   elsif Chars (Choice) /= Name_Dim_Symbol then
1010                      Error_Msg_N ("expected Dim_Symbol, found&", Choice);
1011                   end if;
1012
1013                --  Positional dimension aggregate
1014
1015                else
1016                   Unit_Name   := First (Expressions (Dim_Aggr));
1017                   Unit_Symbol := Next (Unit_Name);
1018                   Dim_Symbol  := Next (Unit_Symbol);
1019                end if;
1020
1021                --  Check the first argument for each dimension aggregate is
1022                --  a name.
1023
1024                if Nkind (Unit_Name) = N_Identifier then
1025                   Unit_Names (Position) := Chars (Unit_Name);
1026                else
1027                   Error_Msg_N ("expected unit name", Unit_Name);
1028                end if;
1029
1030                --  Check the second argument for each dimension aggregate is
1031                --  a string or a character.
1032
1033                if not Nkind_In (Unit_Symbol, N_String_Literal,
1034                                              N_Character_Literal)
1035                then
1036                   Error_Msg_N
1037                     ("expected unit symbol (string or character)",
1038                      Unit_Symbol);
1039
1040                else
1041                   --  String case
1042
1043                   if Nkind (Unit_Symbol) = N_String_Literal then
1044                      Unit_Symbols (Position) := Strval (Unit_Symbol);
1045
1046                   --  Character case
1047
1048                   else
1049                      Start_String;
1050                      Store_String_Char
1051                        (UI_To_CC (Char_Literal_Value (Unit_Symbol)));
1052                      Unit_Symbols (Position) := End_String;
1053                   end if;
1054
1055                   --  Verify that the string is not empty
1056
1057                   if String_Length (Unit_Symbols (Position)) = 0 then
1058                      Error_Msg_N
1059                        ("empty string not allowed here", Unit_Symbol);
1060                   end if;
1061                end if;
1062
1063                --  Check the third argument for each dimension aggregate is
1064                --  a string or a character.
1065
1066                if not Nkind_In (Dim_Symbol, N_String_Literal,
1067                                             N_Character_Literal)
1068                then
1069                   Error_Msg_N
1070                     ("expected dimension symbol (string or character)",
1071                      Dim_Symbol);
1072
1073                else
1074                   --  String case
1075
1076                   if Nkind (Dim_Symbol) = N_String_Literal then
1077                      Dim_Symbols (Position) := Strval (Dim_Symbol);
1078
1079                   --  Character case
1080
1081                   else
1082                      Start_String;
1083                      Store_String_Char
1084                        (UI_To_CC (Char_Literal_Value (Dim_Symbol)));
1085                      Dim_Symbols (Position) := End_String;
1086                   end if;
1087
1088                   --  Verify that the string is not empty
1089
1090                   if String_Length (Dim_Symbols (Position)) = 0 then
1091                      Error_Msg_N ("empty string not allowed here", Dim_Symbol);
1092                   end if;
1093                end if;
1094             end if;
1095          end if;
1096
1097          Next (Dim_Aggr);
1098       end loop;
1099
1100       --  STEP 4: Storage of extracted values
1101
1102       --  Check that no errors have been detected during the analysis
1103
1104       if Errors_Count = Serious_Errors_Detected then
1105          Dim_System.Type_Decl    := N;
1106          Dim_System.Unit_Names   := Unit_Names;
1107          Dim_System.Unit_Symbols := Unit_Symbols;
1108          Dim_System.Dim_Symbols  := Dim_Symbols;
1109          Dim_System.Count        := Position;
1110          System_Table.Append (Dim_System);
1111       end if;
1112    end Analyze_Aspect_Dimension_System;
1113
1114    -----------------------
1115    -- Analyze_Dimension --
1116    -----------------------
1117
1118    --  This dispatch routine propagates dimensions for each node
1119
1120    procedure Analyze_Dimension (N : Node_Id) is
1121    begin
1122       --  Aspect is an Ada 2012 feature. Note that there is no need to check
1123       --  dimensions for nodes that don't come from source, except for subtype
1124       --  declarations where the dimensions are inherited from the base type,
1125       --  and for explicit dereferences generated when expanding iterators.
1126
1127       if Ada_Version < Ada_2012 then
1128          return;
1129
1130       elsif not Comes_From_Source (N)
1131         and then Nkind (N) /= N_Subtype_Declaration
1132         and then Nkind (N) /= N_Explicit_Dereference
1133       then
1134          return;
1135       end if;
1136
1137       case Nkind (N) is
1138          when N_Assignment_Statement =>
1139             Analyze_Dimension_Assignment_Statement (N);
1140
1141          when N_Binary_Op =>
1142             Analyze_Dimension_Binary_Op (N);
1143
1144          when N_Component_Declaration =>
1145             Analyze_Dimension_Component_Declaration (N);
1146
1147          when N_Extended_Return_Statement =>
1148             Analyze_Dimension_Extended_Return_Statement (N);
1149
1150          when N_Attribute_Reference       |
1151               N_Expanded_Name             |
1152               N_Explicit_Dereference      |
1153               N_Function_Call             |
1154               N_Indexed_Component         |
1155               N_Qualified_Expression      |
1156               N_Selected_Component        |
1157               N_Slice                     |
1158               N_Type_Conversion           |
1159               N_Unchecked_Type_Conversion =>
1160             Analyze_Dimension_Has_Etype (N);
1161
1162          --  In the presence of a repaired syntax error, an identifier
1163          --  may be introduced without a usable type.
1164
1165          when  N_Identifier                =>
1166             if Present (Etype (N)) then
1167                Analyze_Dimension_Has_Etype (N);
1168             end if;
1169
1170          when N_Number_Declaration =>
1171             Analyze_Dimension_Number_Declaration (N);
1172
1173          when N_Object_Declaration =>
1174             Analyze_Dimension_Object_Declaration (N);
1175
1176          when N_Object_Renaming_Declaration =>
1177             Analyze_Dimension_Object_Renaming_Declaration (N);
1178
1179          when N_Simple_Return_Statement =>
1180             if not Comes_From_Extended_Return_Statement (N) then
1181                Analyze_Dimension_Simple_Return_Statement (N);
1182             end if;
1183
1184          when N_Subtype_Declaration =>
1185             Analyze_Dimension_Subtype_Declaration (N);
1186
1187          when N_Unary_Op =>
1188             Analyze_Dimension_Unary_Op (N);
1189
1190          when others => null;
1191
1192       end case;
1193    end Analyze_Dimension;
1194
1195    ---------------------------------------
1196    -- Analyze_Dimension_Array_Aggregate --
1197    ---------------------------------------
1198
1199    procedure Analyze_Dimension_Array_Aggregate
1200      (N        : Node_Id;
1201       Comp_Typ : Entity_Id)
1202    is
1203       Comp_Ass         : constant List_Id        := Component_Associations (N);
1204       Dims_Of_Comp_Typ : constant Dimension_Type := Dimensions_Of (Comp_Typ);
1205       Exps             : constant List_Id        := Expressions (N);
1206
1207       Comp : Node_Id;
1208       Expr : Node_Id;
1209
1210       Error_Detected : Boolean := False;
1211       --  This flag is used in order to indicate if an error has been detected
1212       --  so far by the compiler in this routine.
1213
1214    begin
1215       --  Aspect is an Ada 2012 feature. Nothing to do here if the component
1216       --  base type is not a dimensioned type.
1217
1218       --  Note that here the original node must come from source since the
1219       --  original array aggregate may not have been entirely decorated.
1220
1221       if Ada_Version < Ada_2012
1222         or else not Comes_From_Source (Original_Node (N))
1223         or else not Has_Dimension_System (Base_Type (Comp_Typ))
1224       then
1225          return;
1226       end if;
1227
1228       --  Check whether there is any positional component association
1229
1230       if Is_Empty_List (Exps) then
1231          Comp := First (Comp_Ass);
1232       else
1233          Comp := First (Exps);
1234       end if;
1235
1236       while Present (Comp) loop
1237
1238          --  Get the expression from the component
1239
1240          if Nkind (Comp) = N_Component_Association then
1241             Expr := Expression (Comp);
1242          else
1243             Expr := Comp;
1244          end if;
1245
1246          --  Issue an error if the dimensions of the component type and the
1247          --  dimensions of the component mismatch.
1248
1249          --  Note that we must ensure the expression has been fully analyzed
1250          --  since it may not be decorated at this point. We also don't want to
1251          --  issue the same error message multiple times on the same expression
1252          --  (may happen when an aggregate is converted into a positional
1253          --  aggregate). We also must verify that this is a scalar component,
1254          --  and not a subaggregate of a multidimensional aggregate.
1255
1256          if Comes_From_Source (Original_Node (Expr))
1257            and then Present (Etype (Expr))
1258            and then Is_Numeric_Type (Etype (Expr))
1259            and then Dimensions_Of (Expr) /= Dims_Of_Comp_Typ
1260            and then Sloc (Comp) /= Sloc (Prev (Comp))
1261          then
1262             --  Check if an error has already been encountered so far
1263
1264             if not Error_Detected then
1265                Error_Msg_N ("dimensions mismatch in array aggregate", N);
1266                Error_Detected := True;
1267             end if;
1268
1269             Error_Msg_N
1270               ("\expected dimension " & Dimensions_Msg_Of (Comp_Typ)
1271                & ", found " & Dimensions_Msg_Of (Expr), Expr);
1272          end if;
1273
1274          --  Look at the named components right after the positional components
1275
1276          if not Present (Next (Comp))
1277            and then List_Containing (Comp) = Exps
1278          then
1279             Comp := First (Comp_Ass);
1280          else
1281             Next (Comp);
1282          end if;
1283       end loop;
1284    end Analyze_Dimension_Array_Aggregate;
1285
1286    --------------------------------------------
1287    -- Analyze_Dimension_Assignment_Statement --
1288    --------------------------------------------
1289
1290    procedure Analyze_Dimension_Assignment_Statement (N : Node_Id) is
1291       Lhs         : constant Node_Id := Name (N);
1292       Dims_Of_Lhs : constant Dimension_Type := Dimensions_Of (Lhs);
1293       Rhs         : constant Node_Id := Expression (N);
1294       Dims_Of_Rhs : constant Dimension_Type := Dimensions_Of (Rhs);
1295
1296       procedure Error_Dim_Msg_For_Assignment_Statement
1297         (N   : Node_Id;
1298          Lhs : Node_Id;
1299          Rhs : Node_Id);
1300       --  Error using Error_Msg_N at node N. Output the dimensions of left
1301       --  and right hand sides.
1302
1303       --------------------------------------------
1304       -- Error_Dim_Msg_For_Assignment_Statement --
1305       --------------------------------------------
1306
1307       procedure Error_Dim_Msg_For_Assignment_Statement
1308         (N   : Node_Id;
1309          Lhs : Node_Id;
1310          Rhs : Node_Id)
1311       is
1312       begin
1313          Error_Msg_N ("dimensions mismatch in assignment", N);
1314          Error_Msg_N ("\left-hand side "  & Dimensions_Msg_Of (Lhs, True), N);
1315          Error_Msg_N ("\right-hand side " & Dimensions_Msg_Of (Rhs, True), N);
1316       end Error_Dim_Msg_For_Assignment_Statement;
1317
1318    --  Start of processing for Analyze_Dimension_Assignment
1319
1320    begin
1321       if Dims_Of_Lhs /= Dims_Of_Rhs then
1322          Error_Dim_Msg_For_Assignment_Statement (N, Lhs, Rhs);
1323       end if;
1324    end Analyze_Dimension_Assignment_Statement;
1325
1326    ---------------------------------
1327    -- Analyze_Dimension_Binary_Op --
1328    ---------------------------------
1329
1330    --  Check and propagate the dimensions for binary operators
1331    --  Note that when the dimensions mismatch, no dimension is propagated to N.
1332
1333    procedure Analyze_Dimension_Binary_Op (N : Node_Id) is
1334       N_Kind : constant Node_Kind := Nkind (N);
1335
1336       function Dimensions_Of_Operand (N : Node_Id) return Dimension_Type;
1337       --  If the operand is a numeric literal that comes from a declared
1338       --  constant, use the dimensions of the constant which were computed
1339       --  from the expression of the constant declaration.
1340
1341       procedure Error_Dim_Msg_For_Binary_Op (N, L, R : Node_Id);
1342       --  Error using Error_Msg_NE and Error_Msg_N at node N. Output the
1343       --  dimensions of both operands.
1344
1345       ---------------------------
1346       -- Dimensions_Of_Operand --
1347       ---------------------------
1348
1349       function Dimensions_Of_Operand (N : Node_Id) return Dimension_Type is
1350       begin
1351          if Nkind (N) = N_Real_Literal
1352            and then Present (Original_Entity (N))
1353          then
1354             return Dimensions_Of (Original_Entity (N));
1355          else
1356             return Dimensions_Of (N);
1357          end if;
1358       end Dimensions_Of_Operand;
1359
1360       ---------------------------------
1361       -- Error_Dim_Msg_For_Binary_Op --
1362       ---------------------------------
1363
1364       procedure Error_Dim_Msg_For_Binary_Op (N, L, R : Node_Id) is
1365       begin
1366          Error_Msg_NE
1367            ("both operands for operation& must have same dimensions",
1368             N, Entity (N));
1369          Error_Msg_N ("\left operand "  & Dimensions_Msg_Of (L, True), N);
1370          Error_Msg_N ("\right operand " & Dimensions_Msg_Of (R, True), N);
1371       end Error_Dim_Msg_For_Binary_Op;
1372
1373    --  Start of processing for Analyze_Dimension_Binary_Op
1374
1375    begin
1376       if Nkind_In (N_Kind, N_Op_Add, N_Op_Expon, N_Op_Subtract)
1377         or else N_Kind in N_Multiplying_Operator
1378         or else N_Kind in N_Op_Compare
1379       then
1380          declare
1381             L                : constant Node_Id        := Left_Opnd (N);
1382             Dims_Of_L        : constant Dimension_Type :=
1383                                  Dimensions_Of_Operand (L);
1384             L_Has_Dimensions : constant Boolean        := Exists (Dims_Of_L);
1385             R                : constant Node_Id        := Right_Opnd (N);
1386             Dims_Of_R        : constant Dimension_Type :=
1387                                  Dimensions_Of_Operand (R);
1388             R_Has_Dimensions : constant Boolean        := Exists (Dims_Of_R);
1389             Dims_Of_N        : Dimension_Type          := Null_Dimension;
1390
1391          begin
1392             --  N_Op_Add, N_Op_Mod, N_Op_Rem or N_Op_Subtract case
1393
1394             if Nkind_In (N, N_Op_Add, N_Op_Mod, N_Op_Rem, N_Op_Subtract) then
1395
1396                --  Check both operands have same dimension
1397
1398                if Dims_Of_L /= Dims_Of_R then
1399                   Error_Dim_Msg_For_Binary_Op (N, L, R);
1400                else
1401                   --  Check both operands are not dimensionless
1402
1403                   if Exists (Dims_Of_L) then
1404                      Set_Dimensions (N, Dims_Of_L);
1405                   end if;
1406                end if;
1407
1408             --  N_Op_Multiply or N_Op_Divide case
1409
1410             elsif Nkind_In (N_Kind, N_Op_Multiply, N_Op_Divide) then
1411
1412                --  Check at least one operand is not dimensionless
1413
1414                if L_Has_Dimensions or R_Has_Dimensions then
1415
1416                   --  Multiplication case
1417
1418                   --  Get both operands dimensions and add them
1419
1420                   if N_Kind = N_Op_Multiply then
1421                      for Position in Dimension_Type'Range loop
1422                         Dims_Of_N (Position) :=
1423                           Dims_Of_L (Position) + Dims_Of_R (Position);
1424                      end loop;
1425
1426                   --  Division case
1427
1428                   --  Get both operands dimensions and subtract them
1429
1430                   else
1431                      for Position in Dimension_Type'Range loop
1432                         Dims_Of_N (Position) :=
1433                           Dims_Of_L (Position) - Dims_Of_R (Position);
1434                      end loop;
1435                   end if;
1436
1437                   if Exists (Dims_Of_N) then
1438                      Set_Dimensions (N, Dims_Of_N);
1439                   end if;
1440                end if;
1441
1442             --  Exponentiation case
1443
1444             --  Note: a rational exponent is allowed for dimensioned operand
1445
1446             elsif N_Kind = N_Op_Expon then
1447
1448                --  Check the left operand is not dimensionless. Note that the
1449                --  value of the exponent must be known compile time. Otherwise,
1450                --  the exponentiation evaluation will return an error message.
1451
1452                if L_Has_Dimensions then
1453                   if not Compile_Time_Known_Value (R) then
1454                      Error_Msg_N
1455                        ("exponent of dimensioned operand must be "
1456                         & "known at compile time", N);
1457                   end if;
1458
1459                   declare
1460                      Exponent_Value : Rational := Zero;
1461
1462                   begin
1463                      --  Real operand case
1464
1465                      if Is_Real_Type (Etype (L)) then
1466
1467                         --  Define the exponent as a Rational number
1468
1469                         Exponent_Value := Create_Rational_From (R, False);
1470
1471                         --  Verify that the exponent cannot be interpreted
1472                         --  as a rational, otherwise interpret the exponent
1473                         --  as an integer.
1474
1475                         if Exponent_Value = No_Rational then
1476                            Exponent_Value :=
1477                              +Whole (UI_To_Int (Expr_Value (R)));
1478                         end if;
1479
1480                      --  Integer operand case.
1481
1482                      --  For integer operand, the exponent cannot be
1483                      --  interpreted as a rational.
1484
1485                      else
1486                         Exponent_Value := +Whole (UI_To_Int (Expr_Value (R)));
1487                      end if;
1488
1489                      for Position in Dimension_Type'Range loop
1490                         Dims_Of_N (Position) :=
1491                           Dims_Of_L (Position) * Exponent_Value;
1492                      end loop;
1493
1494                      if Exists (Dims_Of_N) then
1495                         Set_Dimensions (N, Dims_Of_N);
1496                      end if;
1497                   end;
1498                end if;
1499
1500             --  Comparison cases
1501
1502             --  For relational operations, only dimension checking is
1503             --  performed (no propagation). If one operand is the result
1504             --  of constant folding the dimensions may have been lost
1505             --  in a tree copy, so assume that pre-analysis has verified
1506             --  that dimensions are correct.
1507
1508             elsif N_Kind in N_Op_Compare then
1509                if (L_Has_Dimensions or R_Has_Dimensions)
1510                  and then Dims_Of_L /= Dims_Of_R
1511                then
1512                   if Nkind (L) = N_Real_Literal
1513                     and then not (Comes_From_Source (L))
1514                     and then Expander_Active
1515                   then
1516                      null;
1517
1518                   elsif Nkind (R) = N_Real_Literal
1519                     and then not (Comes_From_Source (R))
1520                     and then Expander_Active
1521                   then
1522                      null;
1523
1524                   else
1525                      Error_Dim_Msg_For_Binary_Op (N, L, R);
1526                   end if;
1527                end if;
1528             end if;
1529
1530             --  If expander is active, remove dimension information from each
1531             --  operand, as only dimensions of result are relevant.
1532
1533             if Expander_Active then
1534                Remove_Dimensions (L);
1535                Remove_Dimensions (R);
1536             end if;
1537          end;
1538       end if;
1539    end Analyze_Dimension_Binary_Op;
1540
1541    ----------------------------
1542    -- Analyze_Dimension_Call --
1543    ----------------------------
1544
1545    procedure Analyze_Dimension_Call (N : Node_Id; Nam : Entity_Id) is
1546       Actuals        : constant List_Id := Parameter_Associations (N);
1547       Actual         : Node_Id;
1548       Dims_Of_Formal : Dimension_Type;
1549       Formal         : Node_Id;
1550       Formal_Typ     : Entity_Id;
1551
1552       Error_Detected : Boolean := False;
1553       --  This flag is used in order to indicate if an error has been detected
1554       --  so far by the compiler in this routine.
1555
1556    begin
1557       --  Aspect is an Ada 2012 feature. Note that there is no need to check
1558       --  dimensions for calls that don't come from source, or those that may
1559       --  have semantic errors.
1560
1561       if Ada_Version < Ada_2012
1562         or else not Comes_From_Source (N)
1563         or else Error_Posted (N)
1564       then
1565          return;
1566       end if;
1567
1568       --  Check the dimensions of the actuals, if any
1569
1570       if not Is_Empty_List (Actuals) then
1571
1572          --  Special processing for elementary functions
1573
1574          --  For Sqrt call, the resulting dimensions equal to half the
1575          --  dimensions of the actual. For all other elementary calls, this
1576          --  routine check that every actual is dimensionless.
1577
1578          if Nkind (N) = N_Function_Call then
1579             Elementary_Function_Calls : declare
1580                Dims_Of_Call : Dimension_Type;
1581                Ent          : Entity_Id := Nam;
1582
1583                function Is_Elementary_Function_Entity
1584                  (Sub_Id : Entity_Id) return Boolean;
1585                --  Given Sub_Id, the original subprogram entity, return True
1586                --  if call is to an elementary function (see Ada.Numerics.
1587                --  Generic_Elementary_Functions).
1588
1589                -----------------------------------
1590                -- Is_Elementary_Function_Entity --
1591                -----------------------------------
1592
1593                function Is_Elementary_Function_Entity
1594                  (Sub_Id : Entity_Id) return Boolean
1595                is
1596                   Loc : constant Source_Ptr := Sloc (Sub_Id);
1597
1598                begin
1599                   --  Is entity in Ada.Numerics.Generic_Elementary_Functions?
1600
1601                   return
1602                     Loc > No_Location
1603                       and then
1604                         Is_RTU
1605                           (Cunit_Entity (Get_Source_Unit (Loc)),
1606                             Ada_Numerics_Generic_Elementary_Functions);
1607                end Is_Elementary_Function_Entity;
1608
1609             --  Start of processing for Elementary_Function_Calls
1610
1611             begin
1612                --  Get original subprogram entity following the renaming chain
1613
1614                if Present (Alias (Ent)) then
1615                   Ent := Alias (Ent);
1616                end if;
1617
1618                --  Check the call is an Elementary function call
1619
1620                if Is_Elementary_Function_Entity (Ent) then
1621
1622                   --  Sqrt function call case
1623
1624                   if Chars (Ent) = Name_Sqrt then
1625                      Dims_Of_Call := Dimensions_Of (First_Actual (N));
1626
1627                      --  Evaluates the resulting dimensions (i.e. half the
1628                      --  dimensions of the actual).
1629
1630                      if Exists (Dims_Of_Call) then
1631                         for Position in Dims_Of_Call'Range loop
1632                            Dims_Of_Call (Position) :=
1633                              Dims_Of_Call (Position) *
1634                                Rational'(Numerator => 1, Denominator => 2);
1635                         end loop;
1636
1637                         Set_Dimensions (N, Dims_Of_Call);
1638                      end if;
1639
1640                   --  All other elementary functions case. Note that every
1641                   --  actual here should be dimensionless.
1642
1643                   else
1644                      Actual := First_Actual (N);
1645                      while Present (Actual) loop
1646                         if Exists (Dimensions_Of (Actual)) then
1647
1648                            --  Check if error has already been encountered
1649
1650                            if not Error_Detected then
1651                               Error_Msg_NE
1652                                 ("dimensions mismatch in call of&",
1653                                  N, Name (N));
1654                               Error_Detected := True;
1655                            end if;
1656
1657                            Error_Msg_N
1658                              ("\expected dimension '['], found "
1659                               & Dimensions_Msg_Of (Actual), Actual);
1660                         end if;
1661
1662                         Next_Actual (Actual);
1663                      end loop;
1664                   end if;
1665
1666                   --  Nothing more to do for elementary functions
1667
1668                   return;
1669                end if;
1670             end Elementary_Function_Calls;
1671          end if;
1672
1673          --  General case. Check, for each parameter, the dimensions of the
1674          --  actual and its corresponding formal match. Otherwise, complain.
1675
1676          Actual := First_Actual (N);
1677          Formal := First_Formal (Nam);
1678          while Present (Formal) loop
1679
1680             --  A missing corresponding actual indicates that the analysis of
1681             --  the call was aborted due to a previous error.
1682
1683             if No (Actual) then
1684                Check_Error_Detected;
1685                return;
1686             end if;
1687
1688             Formal_Typ     := Etype (Formal);
1689             Dims_Of_Formal := Dimensions_Of (Formal_Typ);
1690
1691             --  If the formal is not dimensionless, check dimensions of formal
1692             --  and actual match. Otherwise, complain.
1693
1694             if Exists (Dims_Of_Formal)
1695               and then Dimensions_Of (Actual) /= Dims_Of_Formal
1696             then
1697                --  Check if an error has already been encountered so far
1698
1699                if not Error_Detected then
1700                   Error_Msg_NE ("dimensions mismatch in& call", N, Name (N));
1701                   Error_Detected := True;
1702                end if;
1703
1704                Error_Msg_N
1705                  ("\expected dimension " & Dimensions_Msg_Of (Formal_Typ)
1706                   & ", found " & Dimensions_Msg_Of (Actual), Actual);
1707             end if;
1708
1709             Next_Actual (Actual);
1710             Next_Formal (Formal);
1711          end loop;
1712       end if;
1713
1714       --  For function calls, propagate the dimensions from the returned type
1715
1716       if Nkind (N) = N_Function_Call then
1717          Analyze_Dimension_Has_Etype (N);
1718       end if;
1719    end Analyze_Dimension_Call;
1720
1721    ---------------------------------------------
1722    -- Analyze_Dimension_Component_Declaration --
1723    ---------------------------------------------
1724
1725    procedure Analyze_Dimension_Component_Declaration (N : Node_Id) is
1726       Expr         : constant Node_Id        := Expression (N);
1727       Id           : constant Entity_Id      := Defining_Identifier (N);
1728       Etyp         : constant Entity_Id      := Etype (Id);
1729       Dims_Of_Etyp : constant Dimension_Type := Dimensions_Of (Etyp);
1730       Dims_Of_Expr : Dimension_Type;
1731
1732       procedure Error_Dim_Msg_For_Component_Declaration
1733         (N    : Node_Id;
1734          Etyp : Entity_Id;
1735          Expr : Node_Id);
1736       --  Error using Error_Msg_N at node N. Output the dimensions of the
1737       --  type Etyp and the expression Expr of N.
1738
1739       ---------------------------------------------
1740       -- Error_Dim_Msg_For_Component_Declaration --
1741       ---------------------------------------------
1742
1743       procedure Error_Dim_Msg_For_Component_Declaration
1744         (N    : Node_Id;
1745          Etyp : Entity_Id;
1746          Expr : Node_Id) is
1747       begin
1748          Error_Msg_N ("dimensions mismatch in component declaration", N);
1749          Error_Msg_N
1750            ("\expected dimension " & Dimensions_Msg_Of (Etyp) & ", found "
1751             & Dimensions_Msg_Of (Expr), Expr);
1752       end Error_Dim_Msg_For_Component_Declaration;
1753
1754    --  Start of processing for Analyze_Dimension_Component_Declaration
1755
1756    begin
1757       --  Expression is present
1758
1759       if Present (Expr) then
1760          Dims_Of_Expr := Dimensions_Of (Expr);
1761
1762          --  Check dimensions match
1763
1764          if Dims_Of_Etyp /= Dims_Of_Expr then
1765
1766             --  Numeric literal case. Issue a warning if the object type is not
1767             --  dimensionless to indicate the literal is treated as if its
1768             --  dimension matches the type dimension.
1769
1770             if Nkind_In (Original_Node (Expr), N_Real_Literal,
1771                                                N_Integer_Literal)
1772             then
1773                Dim_Warning_For_Numeric_Literal (Expr, Etyp);
1774
1775             --  Issue a dimension mismatch error for all other cases
1776
1777             else
1778                Error_Dim_Msg_For_Component_Declaration (N, Etyp, Expr);
1779             end if;
1780          end if;
1781       end if;
1782    end Analyze_Dimension_Component_Declaration;
1783
1784    -------------------------------------------------
1785    -- Analyze_Dimension_Extended_Return_Statement --
1786    -------------------------------------------------
1787
1788    procedure Analyze_Dimension_Extended_Return_Statement (N : Node_Id) is
1789       Return_Ent       : constant Entity_Id := Return_Statement_Entity (N);
1790       Return_Etyp      : constant Entity_Id :=
1791                            Etype (Return_Applies_To (Return_Ent));
1792       Return_Obj_Decls : constant List_Id := Return_Object_Declarations (N);
1793       Return_Obj_Decl  : Node_Id;
1794       Return_Obj_Id    : Entity_Id;
1795       Return_Obj_Typ   : Entity_Id;
1796
1797       procedure Error_Dim_Msg_For_Extended_Return_Statement
1798         (N              : Node_Id;
1799          Return_Etyp    : Entity_Id;
1800          Return_Obj_Typ : Entity_Id);
1801       --  Error using Error_Msg_N at node N. Output dimensions of the returned
1802       --  type Return_Etyp and the returned object type Return_Obj_Typ of N.
1803
1804       -------------------------------------------------
1805       -- Error_Dim_Msg_For_Extended_Return_Statement --
1806       -------------------------------------------------
1807
1808       procedure Error_Dim_Msg_For_Extended_Return_Statement
1809         (N              : Node_Id;
1810          Return_Etyp    : Entity_Id;
1811          Return_Obj_Typ : Entity_Id)
1812       is
1813       begin
1814          Error_Msg_N ("dimensions mismatch in extended return statement", N);
1815          Error_Msg_N
1816            ("\expected dimension " & Dimensions_Msg_Of (Return_Etyp)
1817             & ", found " & Dimensions_Msg_Of (Return_Obj_Typ), N);
1818       end Error_Dim_Msg_For_Extended_Return_Statement;
1819
1820    --  Start of processing for Analyze_Dimension_Extended_Return_Statement
1821
1822    begin
1823       if Present (Return_Obj_Decls) then
1824          Return_Obj_Decl := First (Return_Obj_Decls);
1825          while Present (Return_Obj_Decl) loop
1826             if Nkind (Return_Obj_Decl) = N_Object_Declaration then
1827                Return_Obj_Id := Defining_Identifier (Return_Obj_Decl);
1828
1829                if Is_Return_Object (Return_Obj_Id) then
1830                   Return_Obj_Typ := Etype (Return_Obj_Id);
1831
1832                   --  Issue an error message if dimensions mismatch
1833
1834                   if Dimensions_Of (Return_Etyp) /=
1835                        Dimensions_Of (Return_Obj_Typ)
1836                   then
1837                      Error_Dim_Msg_For_Extended_Return_Statement
1838                        (N, Return_Etyp, Return_Obj_Typ);
1839                      return;
1840                   end if;
1841                end if;
1842             end if;
1843
1844             Next (Return_Obj_Decl);
1845          end loop;
1846       end if;
1847    end Analyze_Dimension_Extended_Return_Statement;
1848
1849    -----------------------------------------------------
1850    -- Analyze_Dimension_Extension_Or_Record_Aggregate --
1851    -----------------------------------------------------
1852
1853    procedure Analyze_Dimension_Extension_Or_Record_Aggregate (N : Node_Id) is
1854       Comp     : Node_Id;
1855       Comp_Id  : Entity_Id;
1856       Comp_Typ : Entity_Id;
1857       Expr     : Node_Id;
1858
1859       Error_Detected : Boolean := False;
1860       --  This flag is used in order to indicate if an error has been detected
1861       --  so far by the compiler in this routine.
1862
1863    begin
1864       --  Aspect is an Ada 2012 feature. Note that there is no need to check
1865       --  dimensions for aggregates that don't come from source, or if we are
1866       --  within an initialization procedure, whose expressions have been
1867       --  checked at the point of record declaration.
1868
1869       if Ada_Version < Ada_2012
1870         or else not Comes_From_Source (N)
1871         or else Inside_Init_Proc
1872       then
1873          return;
1874       end if;
1875
1876       Comp := First (Component_Associations (N));
1877       while Present (Comp) loop
1878          Comp_Id  := Entity (First (Choices (Comp)));
1879          Comp_Typ := Etype (Comp_Id);
1880
1881          --  Check the component type is either a dimensioned type or a
1882          --  dimensioned subtype.
1883
1884          if Has_Dimension_System (Base_Type (Comp_Typ)) then
1885             Expr := Expression (Comp);
1886
1887             --  A box-initialized component needs no checking.
1888
1889             if No (Expr) and then Box_Present (Comp) then
1890                null;
1891
1892             --  Issue an error if the dimensions of the component type and the
1893             --  dimensions of the component mismatch.
1894
1895             elsif Dimensions_Of (Expr) /= Dimensions_Of (Comp_Typ) then
1896
1897                --  Check if an error has already been encountered so far
1898
1899                if not Error_Detected then
1900
1901                   --  Extension aggregate case
1902
1903                   if Nkind (N) = N_Extension_Aggregate then
1904                      Error_Msg_N
1905                        ("dimensions mismatch in extension aggregate", N);
1906
1907                   --  Record aggregate case
1908
1909                   else
1910                      Error_Msg_N
1911                        ("dimensions mismatch in record aggregate", N);
1912                   end if;
1913
1914                   Error_Detected := True;
1915                end if;
1916
1917                Error_Msg_N
1918                  ("\expected dimension " & Dimensions_Msg_Of (Comp_Typ)
1919                   & ", found " & Dimensions_Msg_Of (Expr), Comp);
1920             end if;
1921          end if;
1922
1923          Next (Comp);
1924       end loop;
1925    end Analyze_Dimension_Extension_Or_Record_Aggregate;
1926
1927    -------------------------------
1928    -- Analyze_Dimension_Formals --
1929    -------------------------------
1930
1931    procedure Analyze_Dimension_Formals (N : Node_Id; Formals : List_Id) is
1932       Dims_Of_Typ : Dimension_Type;
1933       Formal      : Node_Id;
1934       Typ         : Entity_Id;
1935
1936    begin
1937       --  Aspect is an Ada 2012 feature. Note that there is no need to check
1938       --  dimensions for sub specs that don't come from source.
1939
1940       if Ada_Version < Ada_2012 or else not Comes_From_Source (N) then
1941          return;
1942       end if;
1943
1944       Formal := First (Formals);
1945       while Present (Formal) loop
1946          Typ         := Parameter_Type (Formal);
1947          Dims_Of_Typ := Dimensions_Of  (Typ);
1948
1949          if Exists (Dims_Of_Typ) then
1950             declare
1951                Expr : constant Node_Id := Expression (Formal);
1952
1953             begin
1954                --  Issue a warning if Expr is a numeric literal and if its
1955                --  dimensions differ with the dimensions of the formal type.
1956
1957                if Present (Expr)
1958                  and then Dims_Of_Typ /= Dimensions_Of (Expr)
1959                  and then Nkind_In (Original_Node (Expr), N_Real_Literal,
1960                                                           N_Integer_Literal)
1961                then
1962                   Dim_Warning_For_Numeric_Literal (Expr, Etype (Typ));
1963                end if;
1964             end;
1965          end if;
1966
1967          Next (Formal);
1968       end loop;
1969    end Analyze_Dimension_Formals;
1970
1971    ---------------------------------
1972    -- Analyze_Dimension_Has_Etype --
1973    ---------------------------------
1974
1975    procedure Analyze_Dimension_Has_Etype (N : Node_Id) is
1976       Etyp         : constant Entity_Id := Etype (N);
1977       Dims_Of_Etyp : Dimension_Type     := Dimensions_Of (Etyp);
1978
1979    begin
1980       --  General case. Propagation of the dimensions from the type
1981
1982       if Exists (Dims_Of_Etyp) then
1983          Set_Dimensions (N, Dims_Of_Etyp);
1984
1985       --  Identifier case. Propagate the dimensions from the entity for
1986       --  identifier whose entity is a non-dimensionless constant.
1987
1988       elsif Nkind (N) = N_Identifier then
1989          Analyze_Dimension_Identifier : declare
1990             Id : constant Entity_Id := Entity (N);
1991
1992          begin
1993             --  If Id is missing, abnormal tree, assume previous error
1994
1995             if No (Id) then
1996                Check_Error_Detected;
1997                return;
1998
1999             elsif Ekind_In (Id,  E_Constant, E_Named_Real)
2000               and then Exists (Dimensions_Of (Id))
2001             then
2002                Set_Dimensions (N, Dimensions_Of (Id));
2003             end if;
2004          end Analyze_Dimension_Identifier;
2005
2006       --  Attribute reference case. Propagate the dimensions from the prefix.
2007
2008       elsif Nkind (N) = N_Attribute_Reference
2009         and then Has_Dimension_System (Base_Type (Etyp))
2010       then
2011          Dims_Of_Etyp := Dimensions_Of (Prefix (N));
2012
2013          --  Check the prefix is not dimensionless
2014
2015          if Exists (Dims_Of_Etyp) then
2016             Set_Dimensions (N, Dims_Of_Etyp);
2017          end if;
2018       end if;
2019
2020       --  Remove dimensions from inner expressions, to prevent dimensions
2021       --  table from growing uselessly.
2022
2023       case Nkind (N) is
2024          when N_Attribute_Reference |
2025               N_Indexed_Component   =>
2026             declare
2027                Expr  : Node_Id;
2028                Exprs : constant List_Id := Expressions (N);
2029             begin
2030                if Present (Exprs) then
2031                   Expr := First (Exprs);
2032                   while Present (Expr) loop
2033                      Remove_Dimensions (Expr);
2034                      Next (Expr);
2035                   end loop;
2036                end if;
2037             end;
2038
2039          when N_Qualified_Expression      |
2040               N_Type_Conversion           |
2041               N_Unchecked_Type_Conversion =>
2042             Remove_Dimensions (Expression (N));
2043
2044          when N_Selected_Component =>
2045             Remove_Dimensions (Selector_Name (N));
2046
2047          when others => null;
2048       end case;
2049    end Analyze_Dimension_Has_Etype;
2050
2051    ------------------------------------------
2052    -- Analyze_Dimension_Number_Declaration --
2053    ------------------------------------------
2054
2055    procedure Analyze_Dimension_Number_Declaration (N : Node_Id) is
2056       Expr        : constant Node_Id        := Expression (N);
2057       Id          : constant Entity_Id      := Defining_Identifier (N);
2058       Dim_Of_Expr : constant Dimension_Type := Dimensions_Of (Expr);
2059
2060    begin
2061       if Exists (Dim_Of_Expr) then
2062          Set_Dimensions (Id, Dim_Of_Expr);
2063          Set_Etype (Id, Etype (Expr));
2064       end if;
2065    end Analyze_Dimension_Number_Declaration;
2066
2067    ------------------------------------------
2068    -- Analyze_Dimension_Object_Declaration --
2069    ------------------------------------------
2070
2071    procedure Analyze_Dimension_Object_Declaration (N : Node_Id) is
2072       Expr        : constant Node_Id   := Expression (N);
2073       Id          : constant Entity_Id := Defining_Identifier (N);
2074       Etyp        : constant Entity_Id := Etype (Id);
2075       Dim_Of_Etyp : constant Dimension_Type := Dimensions_Of (Etyp);
2076       Dim_Of_Expr : Dimension_Type;
2077
2078       procedure Error_Dim_Msg_For_Object_Declaration
2079         (N    : Node_Id;
2080          Etyp : Entity_Id;
2081          Expr : Node_Id);
2082       --  Error using Error_Msg_N at node N. Output the dimensions of the
2083       --  type Etyp and of the expression Expr.
2084
2085       ------------------------------------------
2086       -- Error_Dim_Msg_For_Object_Declaration --
2087       ------------------------------------------
2088
2089       procedure Error_Dim_Msg_For_Object_Declaration
2090         (N    : Node_Id;
2091          Etyp : Entity_Id;
2092          Expr : Node_Id) is
2093       begin
2094          Error_Msg_N ("dimensions mismatch in object declaration", N);
2095          Error_Msg_N
2096            ("\expected dimension " & Dimensions_Msg_Of (Etyp) & ", found "
2097             & Dimensions_Msg_Of (Expr), Expr);
2098       end Error_Dim_Msg_For_Object_Declaration;
2099
2100    --  Start of processing for Analyze_Dimension_Object_Declaration
2101
2102    begin
2103       --  Expression is present
2104
2105       if Present (Expr) then
2106          Dim_Of_Expr := Dimensions_Of (Expr);
2107
2108          --  Check dimensions match
2109
2110          if Dim_Of_Expr /= Dim_Of_Etyp then
2111
2112             --  Numeric literal case. Issue a warning if the object type is not
2113             --  dimensionless to indicate the literal is treated as if its
2114             --  dimension matches the type dimension.
2115
2116             if Nkind_In (Original_Node (Expr), N_Real_Literal,
2117                                                N_Integer_Literal)
2118             then
2119                Dim_Warning_For_Numeric_Literal (Expr, Etyp);
2120
2121             --  Case of object is a constant whose type is a dimensioned type
2122
2123             elsif Constant_Present (N) and then not Exists (Dim_Of_Etyp) then
2124
2125                --  Propagate dimension from expression to object entity
2126
2127                Set_Dimensions (Id, Dim_Of_Expr);
2128
2129             --  For all other cases, issue an error message
2130
2131             else
2132                Error_Dim_Msg_For_Object_Declaration (N, Etyp, Expr);
2133             end if;
2134          end if;
2135
2136          --  Removal of dimensions in expression
2137
2138          Remove_Dimensions (Expr);
2139       end if;
2140    end Analyze_Dimension_Object_Declaration;
2141
2142    ---------------------------------------------------
2143    -- Analyze_Dimension_Object_Renaming_Declaration --
2144    ---------------------------------------------------
2145
2146    procedure Analyze_Dimension_Object_Renaming_Declaration (N : Node_Id) is
2147       Renamed_Name : constant Node_Id := Name (N);
2148       Sub_Mark     : constant Node_Id := Subtype_Mark (N);
2149
2150       procedure Error_Dim_Msg_For_Object_Renaming_Declaration
2151         (N            : Node_Id;
2152          Sub_Mark     : Node_Id;
2153          Renamed_Name : Node_Id);
2154       --  Error using Error_Msg_N at node N. Output the dimensions of
2155       --  Sub_Mark and of Renamed_Name.
2156
2157       ---------------------------------------------------
2158       -- Error_Dim_Msg_For_Object_Renaming_Declaration --
2159       ---------------------------------------------------
2160
2161       procedure Error_Dim_Msg_For_Object_Renaming_Declaration
2162         (N            : Node_Id;
2163          Sub_Mark     : Node_Id;
2164          Renamed_Name : Node_Id) is
2165       begin
2166          Error_Msg_N ("dimensions mismatch in object renaming declaration", N);
2167          Error_Msg_N
2168            ("\expected dimension " & Dimensions_Msg_Of (Sub_Mark) & ", found "
2169             & Dimensions_Msg_Of (Renamed_Name), Renamed_Name);
2170       end Error_Dim_Msg_For_Object_Renaming_Declaration;
2171
2172    --  Start of processing for Analyze_Dimension_Object_Renaming_Declaration
2173
2174    begin
2175       if Dimensions_Of (Renamed_Name) /= Dimensions_Of (Sub_Mark) then
2176          Error_Dim_Msg_For_Object_Renaming_Declaration
2177            (N, Sub_Mark, Renamed_Name);
2178       end if;
2179    end Analyze_Dimension_Object_Renaming_Declaration;
2180
2181    -----------------------------------------------
2182    -- Analyze_Dimension_Simple_Return_Statement --
2183    -----------------------------------------------
2184
2185    procedure Analyze_Dimension_Simple_Return_Statement (N : Node_Id) is
2186       Expr                : constant Node_Id := Expression (N);
2187       Return_Ent          : constant Entity_Id := Return_Statement_Entity (N);
2188       Return_Etyp         : constant Entity_Id :=
2189                               Etype (Return_Applies_To (Return_Ent));
2190       Dims_Of_Return_Etyp : constant Dimension_Type :=
2191                               Dimensions_Of (Return_Etyp);
2192
2193       procedure Error_Dim_Msg_For_Simple_Return_Statement
2194         (N           : Node_Id;
2195          Return_Etyp : Entity_Id;
2196          Expr        : Node_Id);
2197       --  Error using Error_Msg_N at node N. Output the dimensions of the
2198       --  returned type Return_Etyp and the returned expression Expr of N.
2199
2200       -----------------------------------------------
2201       -- Error_Dim_Msg_For_Simple_Return_Statement --
2202       -----------------------------------------------
2203
2204       procedure Error_Dim_Msg_For_Simple_Return_Statement
2205         (N           : Node_Id;
2206          Return_Etyp : Entity_Id;
2207          Expr        : Node_Id)
2208       is
2209       begin
2210          Error_Msg_N ("dimensions mismatch in return statement", N);
2211          Error_Msg_N
2212            ("\expected dimension " & Dimensions_Msg_Of (Return_Etyp)
2213             & ", found " & Dimensions_Msg_Of (Expr), Expr);
2214       end Error_Dim_Msg_For_Simple_Return_Statement;
2215
2216    --  Start of processing for Analyze_Dimension_Simple_Return_Statement
2217
2218    begin
2219       if Dims_Of_Return_Etyp /= Dimensions_Of (Expr) then
2220          Error_Dim_Msg_For_Simple_Return_Statement (N, Return_Etyp, Expr);
2221          Remove_Dimensions (Expr);
2222       end if;
2223    end Analyze_Dimension_Simple_Return_Statement;
2224
2225    -------------------------------------------
2226    -- Analyze_Dimension_Subtype_Declaration --
2227    -------------------------------------------
2228
2229    procedure Analyze_Dimension_Subtype_Declaration (N : Node_Id) is
2230       Id           : constant Entity_Id := Defining_Identifier (N);
2231       Dims_Of_Id   : constant Dimension_Type := Dimensions_Of (Id);
2232       Dims_Of_Etyp : Dimension_Type;
2233       Etyp         : Node_Id;
2234
2235    begin
2236       --  No constraint case in subtype declaration
2237
2238       if Nkind (Subtype_Indication (N)) /= N_Subtype_Indication then
2239          Etyp := Etype (Subtype_Indication (N));
2240          Dims_Of_Etyp := Dimensions_Of (Etyp);
2241
2242          if Exists (Dims_Of_Etyp) then
2243
2244             --  If subtype already has a dimension (from Aspect_Dimension), it
2245             --  cannot inherit different dimensions from its subtype.
2246
2247             if Exists (Dims_Of_Id) and then Dims_Of_Etyp /= Dims_Of_Id then
2248                Error_Msg_NE
2249                  ("subtype& already " & Dimensions_Msg_Of (Id, True), N, Id);
2250             else
2251                Set_Dimensions (Id, Dims_Of_Etyp);
2252                Set_Symbol (Id, Symbol_Of (Etyp));
2253             end if;
2254          end if;
2255
2256       --  Constraint present in subtype declaration
2257
2258       else
2259          Etyp := Etype (Subtype_Mark (Subtype_Indication (N)));
2260          Dims_Of_Etyp := Dimensions_Of (Etyp);
2261
2262          if Exists (Dims_Of_Etyp) then
2263             Set_Dimensions (Id, Dims_Of_Etyp);
2264             Set_Symbol (Id, Symbol_Of (Etyp));
2265          end if;
2266       end if;
2267    end Analyze_Dimension_Subtype_Declaration;
2268
2269    --------------------------------
2270    -- Analyze_Dimension_Unary_Op --
2271    --------------------------------
2272
2273    procedure Analyze_Dimension_Unary_Op (N : Node_Id) is
2274    begin
2275       case Nkind (N) is
2276          when N_Op_Plus | N_Op_Minus | N_Op_Abs =>
2277
2278             --  Propagate the dimension if the operand is not dimensionless
2279
2280             declare
2281                R : constant Node_Id := Right_Opnd (N);
2282             begin
2283                Move_Dimensions (R, N);
2284             end;
2285
2286          when others => null;
2287
2288       end case;
2289    end Analyze_Dimension_Unary_Op;
2290
2291    ---------------------------------
2292    -- Check_Expression_Dimensions --
2293    ---------------------------------
2294
2295    procedure Check_Expression_Dimensions
2296      (Expr : Node_Id;
2297       Typ  : Entity_Id)
2298    is
2299    begin
2300       if Is_Floating_Point_Type (Etype (Expr)) then
2301          Analyze_Dimension (Expr);
2302
2303          if Dimensions_Of (Expr) /= Dimensions_Of (Typ) then
2304             Error_Msg_N ("dimensions mismatch in array aggregate", Expr);
2305             Error_Msg_N
2306               ("\expected dimension " & Dimensions_Msg_Of (Typ)
2307                & ", found " & Dimensions_Msg_Of (Expr), Expr);
2308          end if;
2309       end if;
2310    end Check_Expression_Dimensions;
2311
2312    ---------------------
2313    -- Copy_Dimensions --
2314    ---------------------
2315
2316    procedure Copy_Dimensions (From, To : Node_Id) is
2317       Dims_Of_From : constant Dimension_Type := Dimensions_Of (From);
2318
2319    begin
2320       --  Ignore if not Ada 2012 or beyond
2321
2322       if Ada_Version < Ada_2012 then
2323          return;
2324
2325       --  For Ada 2012, Copy the dimension of 'From to 'To'
2326
2327       elsif Exists (Dims_Of_From) then
2328          Set_Dimensions (To, Dims_Of_From);
2329       end if;
2330    end Copy_Dimensions;
2331
2332    --------------------------
2333    -- Create_Rational_From --
2334    --------------------------
2335
2336    --  RATIONAL ::= [-] NUMERAL [/ NUMERAL]
2337
2338    --  A rational number is a number that can be expressed as the quotient or
2339    --  fraction a/b of two integers, where b is non-zero positive.
2340
2341    function Create_Rational_From
2342      (Expr     : Node_Id;
2343       Complain : Boolean) return Rational
2344    is
2345       Or_Node_Of_Expr : constant Node_Id := Original_Node (Expr);
2346       Result          : Rational := No_Rational;
2347
2348       function Process_Minus (N : Node_Id) return Rational;
2349       --  Create a rational from a N_Op_Minus node
2350
2351       function Process_Divide (N : Node_Id) return Rational;
2352       --  Create a rational from a N_Op_Divide node
2353
2354       function Process_Literal (N : Node_Id) return Rational;
2355       --  Create a rational from a N_Integer_Literal node
2356
2357       -------------------
2358       -- Process_Minus --
2359       -------------------
2360
2361       function Process_Minus (N : Node_Id) return Rational is
2362          Right  : constant Node_Id := Original_Node (Right_Opnd (N));
2363          Result : Rational;
2364
2365       begin
2366          --  Operand is an integer literal
2367
2368          if Nkind (Right) = N_Integer_Literal then
2369             Result := -Process_Literal (Right);
2370
2371          --  Operand is a divide operator
2372
2373          elsif Nkind (Right) = N_Op_Divide then
2374             Result := -Process_Divide (Right);
2375
2376          else
2377             Result := No_Rational;
2378          end if;
2379
2380          --  Provide minimal semantic information on dimension expressions,
2381          --  even though they have no run-time existence. This is for use by
2382          --  ASIS tools, in particular pretty-printing. If generating code
2383          --  standard operator resolution will take place.
2384
2385          if ASIS_Mode then
2386             Set_Entity (N, Standard_Op_Minus);
2387             Set_Etype  (N, Standard_Integer);
2388          end if;
2389
2390          return Result;
2391       end Process_Minus;
2392
2393       --------------------
2394       -- Process_Divide --
2395       --------------------
2396
2397       function Process_Divide (N : Node_Id) return Rational is
2398          Left      : constant Node_Id := Original_Node (Left_Opnd (N));
2399          Right     : constant Node_Id := Original_Node (Right_Opnd (N));
2400          Left_Rat  : Rational;
2401          Result    : Rational := No_Rational;
2402          Right_Rat : Rational;
2403
2404       begin
2405          --  Both left and right operands are integer literals
2406
2407          if Nkind (Left) = N_Integer_Literal
2408               and then
2409             Nkind (Right) = N_Integer_Literal
2410          then
2411             Left_Rat := Process_Literal (Left);
2412             Right_Rat := Process_Literal (Right);
2413             Result := Left_Rat / Right_Rat;
2414          end if;
2415
2416          --  Provide minimal semantic information on dimension expressions,
2417          --  even though they have no run-time existence. This is for use by
2418          --  ASIS tools, in particular pretty-printing. If generating code
2419          --  standard operator resolution will take place.
2420
2421          if ASIS_Mode then
2422             Set_Entity (N, Standard_Op_Divide);
2423             Set_Etype  (N, Standard_Integer);
2424          end if;
2425
2426          return Result;
2427       end Process_Divide;
2428
2429       ---------------------
2430       -- Process_Literal --
2431       ---------------------
2432
2433       function Process_Literal (N : Node_Id) return Rational is
2434       begin
2435          return +Whole (UI_To_Int (Intval (N)));
2436       end Process_Literal;
2437
2438    --  Start of processing for Create_Rational_From
2439
2440    begin
2441       --  Check the expression is either a division of two integers or an
2442       --  integer itself. Note that the check applies to the original node
2443       --  since the node could have already been rewritten.
2444
2445       --  Integer literal case
2446
2447       if Nkind (Or_Node_Of_Expr) = N_Integer_Literal then
2448          Result := Process_Literal (Or_Node_Of_Expr);
2449
2450       --  Divide operator case
2451
2452       elsif Nkind (Or_Node_Of_Expr) = N_Op_Divide then
2453          Result := Process_Divide (Or_Node_Of_Expr);
2454
2455       --  Minus operator case
2456
2457       elsif Nkind (Or_Node_Of_Expr) = N_Op_Minus then
2458          Result := Process_Minus (Or_Node_Of_Expr);
2459       end if;
2460
2461       --  When Expr cannot be interpreted as a rational and Complain is true,
2462       --  generate an error message.
2463
2464       if Complain and then Result = No_Rational then
2465          Error_Msg_N ("rational expected", Expr);
2466       end if;
2467
2468       return Result;
2469    end Create_Rational_From;
2470
2471    -------------------
2472    -- Dimensions_Of --
2473    -------------------
2474
2475    function Dimensions_Of (N : Node_Id) return Dimension_Type is
2476    begin
2477       return Dimension_Table.Get (N);
2478    end Dimensions_Of;
2479
2480    -----------------------
2481    -- Dimensions_Msg_Of --
2482    -----------------------
2483
2484    function Dimensions_Msg_Of
2485       (N                  : Node_Id;
2486        Description_Needed : Boolean := False) return String
2487    is
2488       Dims_Of_N      : constant Dimension_Type := Dimensions_Of (N);
2489       Dimensions_Msg : Name_Id;
2490       System         : System_Type;
2491
2492    begin
2493       --  Initialization of Name_Buffer
2494
2495       Name_Len := 0;
2496
2497       --  N is not dimensionless
2498
2499       if Exists (Dims_Of_N) then
2500          System := System_Of (Base_Type (Etype (N)));
2501
2502          --  When Description_Needed, add to string "has dimension " before the
2503          --  actual dimension.
2504
2505          if Description_Needed then
2506             Add_Str_To_Name_Buffer ("has dimension ");
2507          end if;
2508
2509          Add_String_To_Name_Buffer
2510            (From_Dim_To_Str_Of_Dim_Symbols (Dims_Of_N, System, True));
2511
2512       --  N is dimensionless
2513
2514       --  When Description_Needed, return "is dimensionless"
2515
2516       elsif Description_Needed then
2517          Add_Str_To_Name_Buffer ("is dimensionless");
2518
2519       --  Otherwise, return "'[']"
2520
2521       else
2522          Add_Str_To_Name_Buffer ("'[']");
2523       end if;
2524
2525       Dimensions_Msg := Name_Find;
2526       return Get_Name_String (Dimensions_Msg);
2527    end Dimensions_Msg_Of;
2528
2529    --------------------------
2530    -- Dimension_Table_Hash --
2531    --------------------------
2532
2533    function Dimension_Table_Hash
2534      (Key : Node_Id) return Dimension_Table_Range
2535    is
2536    begin
2537       return Dimension_Table_Range (Key mod 511);
2538    end Dimension_Table_Hash;
2539
2540    -------------------------------------
2541    -- Dim_Warning_For_Numeric_Literal --
2542    -------------------------------------
2543
2544    procedure Dim_Warning_For_Numeric_Literal (N : Node_Id; Typ : Entity_Id) is
2545    begin
2546       --  Initialize name buffer
2547
2548       Name_Len := 0;
2549
2550       Add_String_To_Name_Buffer (String_From_Numeric_Literal (N));
2551
2552       --  Insert a blank between the literal and the symbol
2553
2554       Add_Str_To_Name_Buffer (" ");
2555       Add_String_To_Name_Buffer (Symbol_Of (Typ));
2556
2557       Error_Msg_Name_1 := Name_Find;
2558       Error_Msg_N ("assumed to be%%??", N);
2559    end Dim_Warning_For_Numeric_Literal;
2560
2561    ----------------------------------------
2562    -- Eval_Op_Expon_For_Dimensioned_Type --
2563    ----------------------------------------
2564
2565    --  Evaluate the expon operator for real dimensioned type.
2566
2567    --  Note that if the exponent is an integer (denominator = 1) the node is
2568    --  evaluated by the regular Eval_Op_Expon routine (see Sem_Eval).
2569
2570    procedure Eval_Op_Expon_For_Dimensioned_Type
2571      (N    : Node_Id;
2572       Btyp : Entity_Id)
2573    is
2574       R       : constant Node_Id := Right_Opnd (N);
2575       R_Value : Rational := No_Rational;
2576
2577    begin
2578       if Is_Real_Type (Btyp) then
2579          R_Value := Create_Rational_From (R, False);
2580       end if;
2581
2582       --  Check that the exponent is not an integer
2583
2584       if R_Value /= No_Rational and then R_Value.Denominator /= 1 then
2585          Eval_Op_Expon_With_Rational_Exponent (N, R_Value);
2586       else
2587          Eval_Op_Expon (N);
2588       end if;
2589    end Eval_Op_Expon_For_Dimensioned_Type;
2590
2591    ------------------------------------------
2592    -- Eval_Op_Expon_With_Rational_Exponent --
2593    ------------------------------------------
2594
2595    --  For dimensioned operand in exponentiation, exponent is allowed to be a
2596    --  Rational and not only an Integer like for dimensionless operands. For
2597    --  that particular case, the left operand is rewritten as a function call
2598    --  using the function Expon_LLF from s-llflex.ads.
2599
2600    procedure Eval_Op_Expon_With_Rational_Exponent
2601      (N              : Node_Id;
2602       Exponent_Value : Rational)
2603    is
2604       Loc                   : constant Source_Ptr     := Sloc (N);
2605       Dims_Of_N             : constant Dimension_Type := Dimensions_Of (N);
2606       L                     : constant Node_Id        := Left_Opnd (N);
2607       Etyp_Of_L             : constant Entity_Id      := Etype (L);
2608       Btyp_Of_L             : constant Entity_Id      := Base_Type (Etyp_Of_L);
2609       Actual_1              : Node_Id;
2610       Actual_2              : Node_Id;
2611       Dim_Power             : Rational;
2612       List_Of_Dims          : List_Id;
2613       New_Aspect            : Node_Id;
2614       New_Aspects           : List_Id;
2615       New_Id                : Entity_Id;
2616       New_N                 : Node_Id;
2617       New_Subtyp_Decl_For_L : Node_Id;
2618       System                : System_Type;
2619
2620    begin
2621       --  Case when the operand is not dimensionless
2622
2623       if Exists (Dims_Of_N) then
2624
2625          --  Get the corresponding System_Type to know the exact number of
2626          --  dimensions in the system.
2627
2628          System := System_Of (Btyp_Of_L);
2629
2630          --  Generation of a new subtype with the proper dimensions
2631
2632          --  In order to rewrite the operator as a type conversion, a new
2633          --  dimensioned subtype with the resulting dimensions of the
2634          --  exponentiation must be created.
2635
2636          --  Generate:
2637
2638          --  Btyp_Of_L   : constant Entity_Id := Base_Type (Etyp_Of_L);
2639          --  System      : constant System_Id :=
2640          --                  Get_Dimension_System_Id (Btyp_Of_L);
2641          --  Num_Of_Dims : constant Number_Of_Dimensions :=
2642          --                  Dimension_Systems.Table (System).Dimension_Count;
2643
2644          --  subtype T is Btyp_Of_L
2645          --    with
2646          --      Dimension => (
2647          --        Dims_Of_N (1).Numerator / Dims_Of_N (1).Denominator,
2648          --        Dims_Of_N (2).Numerator / Dims_Of_N (2).Denominator,
2649          --        ...
2650          --        Dims_Of_N (Num_Of_Dims).Numerator /
2651          --          Dims_Of_N (Num_Of_Dims).Denominator);
2652
2653          --  Step 1: Generate the new aggregate for the aspect Dimension
2654
2655          New_Aspects  := Empty_List;
2656
2657          List_Of_Dims := New_List;
2658          for Position in Dims_Of_N'First ..  System.Count loop
2659             Dim_Power := Dims_Of_N (Position);
2660             Append_To (List_Of_Dims,
2661                Make_Op_Divide (Loc,
2662                  Left_Opnd  =>
2663                    Make_Integer_Literal (Loc, Int (Dim_Power.Numerator)),
2664                  Right_Opnd =>
2665                    Make_Integer_Literal (Loc, Int (Dim_Power.Denominator))));
2666          end loop;
2667
2668          --  Step 2: Create the new Aspect Specification for Aspect Dimension
2669
2670          New_Aspect :=
2671            Make_Aspect_Specification (Loc,
2672              Identifier => Make_Identifier (Loc, Name_Dimension),
2673              Expression => Make_Aggregate (Loc, Expressions => List_Of_Dims));
2674
2675          --  Step 3: Make a temporary identifier for the new subtype
2676
2677          New_Id := Make_Temporary (Loc, 'T');
2678          Set_Is_Internal (New_Id);
2679
2680          --  Step 4: Declaration of the new subtype
2681
2682          New_Subtyp_Decl_For_L :=
2683             Make_Subtype_Declaration (Loc,
2684                Defining_Identifier => New_Id,
2685                Subtype_Indication  => New_Occurrence_Of (Btyp_Of_L, Loc));
2686
2687          Append (New_Aspect, New_Aspects);
2688          Set_Parent (New_Aspects, New_Subtyp_Decl_For_L);
2689          Set_Aspect_Specifications (New_Subtyp_Decl_For_L, New_Aspects);
2690
2691          Analyze (New_Subtyp_Decl_For_L);
2692
2693       --  Case where the operand is dimensionless
2694
2695       else
2696          New_Id := Btyp_Of_L;
2697       end if;
2698
2699       --  Replacement of N by New_N
2700
2701       --  Generate:
2702
2703       --  Actual_1 := Long_Long_Float (L),
2704
2705       --  Actual_2 := Long_Long_Float (Exponent_Value.Numerator) /
2706       --                Long_Long_Float (Exponent_Value.Denominator);
2707
2708       --  (T (Expon_LLF (Actual_1, Actual_2)));
2709
2710       --  where T is the subtype declared in step 1
2711
2712       --  The node is rewritten as a type conversion
2713
2714       --  Step 1: Creation of the two parameters of Expon_LLF function call
2715
2716       Actual_1 :=
2717         Make_Type_Conversion (Loc,
2718           Subtype_Mark => New_Occurrence_Of (Standard_Long_Long_Float, Loc),
2719           Expression   => Relocate_Node (L));
2720
2721       Actual_2 :=
2722         Make_Op_Divide (Loc,
2723           Left_Opnd  =>
2724             Make_Real_Literal (Loc,
2725               UR_From_Uint (UI_From_Int (Int (Exponent_Value.Numerator)))),
2726           Right_Opnd =>
2727             Make_Real_Literal (Loc,
2728               UR_From_Uint (UI_From_Int (Int (Exponent_Value.Denominator)))));
2729
2730       --  Step 2: Creation of New_N
2731
2732       New_N :=
2733          Make_Type_Conversion (Loc,
2734            Subtype_Mark => New_Occurrence_Of (New_Id, Loc),
2735            Expression   =>
2736              Make_Function_Call (Loc,
2737                Name => New_Occurrence_Of (RTE (RE_Expon_LLF), Loc),
2738                Parameter_Associations => New_List (
2739                  Actual_1, Actual_2)));
2740
2741       --  Step 3: Rewrite N with the result
2742
2743       Rewrite (N, New_N);
2744       Set_Etype (N, New_Id);
2745       Analyze_And_Resolve (N, New_Id);
2746    end Eval_Op_Expon_With_Rational_Exponent;
2747
2748    ------------
2749    -- Exists --
2750    ------------
2751
2752    function Exists (Dim : Dimension_Type) return Boolean is
2753    begin
2754       return Dim /= Null_Dimension;
2755    end Exists;
2756
2757    function Exists (Str : String_Id) return Boolean is
2758    begin
2759       return Str /= No_String;
2760    end Exists;
2761
2762    function Exists (Sys : System_Type) return Boolean is
2763    begin
2764       return Sys /= Null_System;
2765    end Exists;
2766
2767    ---------------------------------
2768    -- Expand_Put_Call_With_Symbol --
2769    ---------------------------------
2770
2771    --  For procedure Put (resp. Put_Dim_Of) and function Image, defined in
2772    --  System.Dim.Float_IO or System.Dim.Integer_IO, the default string
2773    --  parameter is rewritten to include the unit symbol (or the dimension
2774    --  symbols if not a defined quantity) in the output of a dimensioned
2775    --  object.  If a value is already supplied by the user for the parameter
2776    --  Symbol, it is used as is.
2777
2778    --  Case 1. Item is dimensionless
2779
2780    --   * Put        : Item appears without a suffix
2781
2782    --   * Put_Dim_Of : the output is []
2783
2784    --      Obj : Mks_Type := 2.6;
2785    --      Put (Obj, 1, 1, 0);
2786    --      Put_Dim_Of (Obj);
2787
2788    --      The corresponding outputs are:
2789    --      $2.6
2790    --      $[]
2791
2792    --  Case 2. Item has a dimension
2793
2794    --   * Put        : If the type of Item is a dimensioned subtype whose
2795    --                  symbol is not empty, then the symbol appears as a
2796    --                  suffix. Otherwise, a new string is created and appears
2797    --                  as a suffix of Item. This string results in the
2798    --                  successive concatanations between each unit symbol
2799    --                  raised by its corresponding dimension power from the
2800    --                  dimensions of Item.
2801
2802    --   * Put_Dim_Of : The output is a new string resulting in the successive
2803    --                  concatanations between each dimension symbol raised by
2804    --                  its corresponding dimension power from the dimensions of
2805    --                  Item.
2806
2807    --      subtype Random is Mks_Type
2808    --        with
2809    --         Dimension => (
2810    --           Meter =>   3,
2811    --           Candela => -1,
2812    --           others =>  0);
2813
2814    --      Obj : Random := 5.0;
2815    --      Put (Obj);
2816    --      Put_Dim_Of (Obj);
2817
2818    --      The corresponding outputs are:
2819    --      $5.0 m**3.cd**(-1)
2820    --      $[l**3.J**(-1)]
2821
2822    --      The function Image returns the string identical to that produced by
2823    --      a call to Put whose first parameter is a string.
2824
2825    procedure Expand_Put_Call_With_Symbol (N : Node_Id) is
2826       Actuals        : constant List_Id := Parameter_Associations (N);
2827       Loc            : constant Source_Ptr := Sloc (N);
2828       Name_Call      : constant Node_Id := Name (N);
2829       New_Actuals    : constant List_Id := New_List;
2830       Actual         : Node_Id;
2831       Dims_Of_Actual : Dimension_Type;
2832       Etyp           : Entity_Id;
2833       New_Str_Lit    : Node_Id := Empty;
2834       Symbols        : String_Id;
2835
2836       Is_Put_Dim_Of : Boolean := False;
2837       --  This flag is used in order to differentiate routines Put and
2838       --  Put_Dim_Of. Set to True if the procedure is one of the Put_Dim_Of
2839       --  defined in System.Dim.Float_IO or System.Dim.Integer_IO.
2840
2841       function Has_Symbols return Boolean;
2842       --  Return True if the current Put call already has a parameter
2843       --  association for parameter "Symbols" with the correct string of
2844       --  symbols.
2845
2846       function Is_Procedure_Put_Call return Boolean;
2847       --  Return True if the current call is a call of an instantiation of a
2848       --  procedure Put defined in the package System.Dim.Float_IO and
2849       --  System.Dim.Integer_IO.
2850
2851       function Item_Actual return Node_Id;
2852       --  Return the item actual parameter node in the output call
2853
2854       -----------------
2855       -- Has_Symbols --
2856       -----------------
2857
2858       function Has_Symbols return Boolean is
2859          Actual     : Node_Id;
2860          Actual_Str : Node_Id;
2861
2862       begin
2863          --  Look for a symbols parameter association in the list of actuals
2864
2865          Actual := First (Actuals);
2866          while Present (Actual) loop
2867
2868             --  Positional parameter association case when the actual is a
2869             --  string literal.
2870
2871             if Nkind (Actual) = N_String_Literal then
2872                Actual_Str := Actual;
2873
2874             --  Named parameter association case when selector name is Symbol
2875
2876             elsif Nkind (Actual) = N_Parameter_Association
2877               and then Chars (Selector_Name (Actual)) = Name_Symbol
2878             then
2879                Actual_Str := Explicit_Actual_Parameter (Actual);
2880
2881             --  Ignore all other cases
2882
2883             else
2884                Actual_Str := Empty;
2885             end if;
2886
2887             if Present (Actual_Str) then
2888
2889                --  Return True if the actual comes from source or if the string
2890                --  of symbols doesn't have the default value (i.e. it is ""),
2891                --  in which case it is used as suffix of the generated string.
2892
2893                if Comes_From_Source (Actual)
2894                  or else String_Length (Strval (Actual_Str)) /= 0
2895                then
2896                   return True;
2897
2898                else
2899                   return False;
2900                end if;
2901             end if;
2902
2903             Next (Actual);
2904          end loop;
2905
2906          --  At this point, the call has no parameter association. Look to the
2907          --  last actual since the symbols parameter is the last one.
2908
2909          return Nkind (Last (Actuals)) = N_String_Literal;
2910       end Has_Symbols;
2911
2912       ---------------------------
2913       -- Is_Procedure_Put_Call --
2914       ---------------------------
2915
2916       function Is_Procedure_Put_Call return Boolean is
2917          Ent : Entity_Id;
2918          Loc : Source_Ptr;
2919
2920       begin
2921          --  There are three different Put (resp. Put_Dim_Of) routines in each
2922          --  generic dim IO package. Verify the current procedure call is one
2923          --  of them.
2924
2925          if Is_Entity_Name (Name_Call) then
2926             Ent := Entity (Name_Call);
2927
2928             --  Get the original subprogram entity following the renaming chain
2929
2930             if Present (Alias (Ent)) then
2931                Ent := Alias (Ent);
2932             end if;
2933
2934             Loc := Sloc (Ent);
2935
2936             --  Check the name of the entity subprogram is Put (resp.
2937             --  Put_Dim_Of) and verify this entity is located in either
2938             --  System.Dim.Float_IO or System.Dim.Integer_IO.
2939
2940             if Loc > No_Location
2941               and then Is_Dim_IO_Package_Entity
2942                          (Cunit_Entity (Get_Source_Unit (Loc)))
2943             then
2944                if Chars (Ent) = Name_Put_Dim_Of then
2945                   Is_Put_Dim_Of := True;
2946                   return True;
2947
2948                elsif Chars (Ent) = Name_Put
2949                  or else Chars (Ent) = Name_Image
2950                then
2951                   return True;
2952                end if;
2953             end if;
2954          end if;
2955
2956          return False;
2957       end Is_Procedure_Put_Call;
2958
2959       -----------------
2960       -- Item_Actual --
2961       -----------------
2962
2963       function Item_Actual return Node_Id is
2964          Actual : Node_Id;
2965
2966       begin
2967          --  Look for the item actual as a parameter association
2968
2969          Actual := First (Actuals);
2970          while Present (Actual) loop
2971             if Nkind (Actual) = N_Parameter_Association
2972               and then Chars (Selector_Name (Actual)) = Name_Item
2973             then
2974                return Explicit_Actual_Parameter (Actual);
2975             end if;
2976
2977             Next (Actual);
2978          end loop;
2979
2980          --  Case where the item has been defined without an association
2981
2982          Actual := First (Actuals);
2983
2984          --  Depending on the procedure Put, Item actual could be first or
2985          --  second in the list of actuals.
2986
2987          if Has_Dimension_System (Base_Type (Etype (Actual))) then
2988             return Actual;
2989          else
2990             return Next (Actual);
2991          end if;
2992       end Item_Actual;
2993
2994    --  Start of processing for Expand_Put_Call_With_Symbol
2995
2996    begin
2997       if Is_Procedure_Put_Call and then not Has_Symbols then
2998          Actual := Item_Actual;
2999          Dims_Of_Actual := Dimensions_Of (Actual);
3000          Etyp := Etype (Actual);
3001
3002          --  Put_Dim_Of case
3003
3004          if Is_Put_Dim_Of then
3005
3006             --  Check that the item is not dimensionless
3007
3008             --  Create the new String_Literal with the new String_Id generated
3009             --  by the routine From_Dim_To_Str_Of_Dim_Symbols.
3010
3011             if Exists (Dims_Of_Actual) then
3012                New_Str_Lit :=
3013                  Make_String_Literal (Loc,
3014                    From_Dim_To_Str_Of_Dim_Symbols
3015                      (Dims_Of_Actual, System_Of (Base_Type (Etyp))));
3016
3017             --  If dimensionless, the output is []
3018
3019             else
3020                New_Str_Lit :=
3021                  Make_String_Literal (Loc, "[]");
3022             end if;
3023
3024          --  Put case
3025
3026          else
3027             --  Add the symbol as a suffix of the value if the subtype has a
3028             --  unit symbol or if the parameter is not dimensionless.
3029
3030             if Exists (Symbol_Of (Etyp)) then
3031                Symbols := Symbol_Of (Etyp);
3032             else
3033                Symbols := From_Dim_To_Str_Of_Unit_Symbols
3034                             (Dims_Of_Actual, System_Of (Base_Type (Etyp)));
3035             end if;
3036
3037             --  Check Symbols exists
3038
3039             if Exists (Symbols) then
3040                Start_String;
3041
3042                --  Put a space between the value and the dimension
3043
3044                Store_String_Char (' ');
3045                Store_String_Chars (Symbols);
3046                New_Str_Lit := Make_String_Literal (Loc, End_String);
3047             end if;
3048          end if;
3049
3050          if Present (New_Str_Lit) then
3051
3052             --  Insert all actuals in New_Actuals
3053
3054             Actual := First (Actuals);
3055             while Present (Actual) loop
3056
3057                --  Copy every actuals in New_Actuals except the Symbols
3058                --  parameter association.
3059
3060                if Nkind (Actual) = N_Parameter_Association
3061                  and then Chars (Selector_Name (Actual)) /= Name_Symbol
3062                then
3063                   Append_To (New_Actuals,
3064                      Make_Parameter_Association (Loc,
3065                         Selector_Name => New_Copy (Selector_Name (Actual)),
3066                         Explicit_Actual_Parameter =>
3067                            New_Copy (Explicit_Actual_Parameter (Actual))));
3068
3069                elsif Nkind (Actual) /= N_Parameter_Association then
3070                   Append_To (New_Actuals, New_Copy (Actual));
3071                end if;
3072
3073                Next (Actual);
3074             end loop;
3075
3076             --  Create new Symbols param association and append to New_Actuals
3077
3078             Append_To (New_Actuals,
3079               Make_Parameter_Association (Loc,
3080                 Selector_Name => Make_Identifier (Loc, Name_Symbol),
3081                 Explicit_Actual_Parameter => New_Str_Lit));
3082
3083             --  Rewrite and analyze the procedure call
3084
3085             if Chars (Name_Call) = Name_Image then
3086                Rewrite (N,
3087                  Make_Function_Call (Loc,
3088                    Name =>                   New_Copy (Name_Call),
3089                    Parameter_Associations => New_Actuals));
3090                Analyze_And_Resolve (N);
3091             else
3092                Rewrite (N,
3093                  Make_Procedure_Call_Statement (Loc,
3094                    Name =>                   New_Copy (Name_Call),
3095                    Parameter_Associations => New_Actuals));
3096                Analyze (N);
3097             end if;
3098
3099          end if;
3100       end if;
3101    end Expand_Put_Call_With_Symbol;
3102
3103    ------------------------------------
3104    -- From_Dim_To_Str_Of_Dim_Symbols --
3105    ------------------------------------
3106
3107    --  Given a dimension vector and the corresponding dimension system, create
3108    --  a String_Id to output dimension symbols corresponding to the dimensions
3109    --  Dims. If In_Error_Msg is True, there is a special handling for character
3110    --  asterisk * which is an insertion character in error messages.
3111
3112    function From_Dim_To_Str_Of_Dim_Symbols
3113      (Dims         : Dimension_Type;
3114       System       : System_Type;
3115       In_Error_Msg : Boolean := False) return String_Id
3116    is
3117       Dim_Power : Rational;
3118       First_Dim : Boolean := True;
3119
3120       procedure Store_String_Oexpon;
3121       --  Store the expon operator symbol "**" in the string. In error
3122       --  messages, asterisk * is a special character and must be quoted
3123       --  to be placed literally into the message.
3124
3125       -------------------------
3126       -- Store_String_Oexpon --
3127       -------------------------
3128
3129       procedure Store_String_Oexpon is
3130       begin
3131          if In_Error_Msg then
3132             Store_String_Chars ("'*'*");
3133          else
3134             Store_String_Chars ("**");
3135          end if;
3136       end Store_String_Oexpon;
3137
3138    --  Start of processing for From_Dim_To_Str_Of_Dim_Symbols
3139
3140    begin
3141       --  Initialization of the new String_Id
3142
3143       Start_String;
3144
3145       --  Store the dimension symbols inside boxes
3146
3147       if In_Error_Msg then
3148          Store_String_Chars ("'[");
3149       else
3150          Store_String_Char ('[');
3151       end if;
3152
3153       for Position in Dimension_Type'Range loop
3154          Dim_Power := Dims (Position);
3155          if Dim_Power /= Zero then
3156
3157             if First_Dim then
3158                First_Dim := False;
3159             else
3160                Store_String_Char ('.');
3161             end if;
3162
3163             Store_String_Chars (System.Dim_Symbols (Position));
3164
3165             --  Positive dimension case
3166
3167             if Dim_Power.Numerator > 0 then
3168
3169                --  Integer case
3170
3171                if Dim_Power.Denominator = 1 then
3172                   if Dim_Power.Numerator /= 1 then
3173                      Store_String_Oexpon;
3174                      Store_String_Int (Int (Dim_Power.Numerator));
3175                   end if;
3176
3177                --  Rational case when denominator /= 1
3178
3179                else
3180                   Store_String_Oexpon;
3181                   Store_String_Char ('(');
3182                   Store_String_Int (Int (Dim_Power.Numerator));
3183                   Store_String_Char ('/');
3184                   Store_String_Int (Int (Dim_Power.Denominator));
3185                   Store_String_Char (')');
3186                end if;
3187
3188             --  Negative dimension case
3189
3190             else
3191                Store_String_Oexpon;
3192                Store_String_Char ('(');
3193                Store_String_Char ('-');
3194                Store_String_Int (Int (-Dim_Power.Numerator));
3195
3196                --  Integer case
3197
3198                if Dim_Power.Denominator = 1 then
3199                   Store_String_Char (')');
3200
3201                --  Rational case when denominator /= 1
3202
3203                else
3204                   Store_String_Char ('/');
3205                   Store_String_Int (Int (Dim_Power.Denominator));
3206                   Store_String_Char (')');
3207                end if;
3208             end if;
3209          end if;
3210       end loop;
3211
3212       if In_Error_Msg then
3213          Store_String_Chars ("']");
3214       else
3215          Store_String_Char (']');
3216       end if;
3217
3218       return End_String;
3219    end From_Dim_To_Str_Of_Dim_Symbols;
3220
3221    -------------------------------------
3222    -- From_Dim_To_Str_Of_Unit_Symbols --
3223    -------------------------------------
3224
3225    --  Given a dimension vector and the corresponding dimension system,
3226    --  create a String_Id to output the unit symbols corresponding to the
3227    --  dimensions Dims.
3228
3229    function From_Dim_To_Str_Of_Unit_Symbols
3230      (Dims   : Dimension_Type;
3231       System : System_Type) return String_Id
3232    is
3233       Dim_Power : Rational;
3234       First_Dim : Boolean := True;
3235
3236    begin
3237       --  Return No_String if dimensionless
3238
3239       if not Exists (Dims) then
3240          return No_String;
3241       end if;
3242
3243       --  Initialization of the new String_Id
3244
3245       Start_String;
3246
3247       for Position in Dimension_Type'Range loop
3248          Dim_Power := Dims (Position);
3249
3250          if Dim_Power /= Zero then
3251             if First_Dim then
3252                First_Dim := False;
3253             else
3254                Store_String_Char ('.');
3255             end if;
3256
3257             Store_String_Chars (System.Unit_Symbols (Position));
3258
3259             --  Positive dimension case
3260
3261             if Dim_Power.Numerator > 0 then
3262
3263                --  Integer case
3264
3265                if Dim_Power.Denominator = 1 then
3266                   if Dim_Power.Numerator /= 1 then
3267                      Store_String_Chars ("**");
3268                      Store_String_Int (Int (Dim_Power.Numerator));
3269                   end if;
3270
3271                --  Rational case when denominator /= 1
3272
3273                else
3274                   Store_String_Chars ("**");
3275                   Store_String_Char ('(');
3276                   Store_String_Int (Int (Dim_Power.Numerator));
3277                   Store_String_Char ('/');
3278                   Store_String_Int (Int (Dim_Power.Denominator));
3279                   Store_String_Char (')');
3280                end if;
3281
3282             --  Negative dimension case
3283
3284             else
3285                Store_String_Chars ("**");
3286                Store_String_Char ('(');
3287                Store_String_Char ('-');
3288                Store_String_Int (Int (-Dim_Power.Numerator));
3289
3290                --  Integer case
3291
3292                if Dim_Power.Denominator = 1 then
3293                   Store_String_Char (')');
3294
3295                --  Rational case when denominator /= 1
3296
3297                else
3298                   Store_String_Char ('/');
3299                   Store_String_Int (Int (Dim_Power.Denominator));
3300                   Store_String_Char (')');
3301                end if;
3302             end if;
3303          end if;
3304       end loop;
3305
3306       return End_String;
3307    end From_Dim_To_Str_Of_Unit_Symbols;
3308
3309    ---------
3310    -- GCD --
3311    ---------
3312
3313    function GCD (Left, Right : Whole) return Int is
3314       L : Whole;
3315       R : Whole;
3316
3317    begin
3318       L := Left;
3319       R := Right;
3320       while R /= 0 loop
3321          L := L mod R;
3322
3323          if L = 0 then
3324             return Int (R);
3325          end if;
3326
3327          R := R mod L;
3328       end loop;
3329
3330       return Int (L);
3331    end GCD;
3332
3333    --------------------------
3334    -- Has_Dimension_System --
3335    --------------------------
3336
3337    function Has_Dimension_System (Typ : Entity_Id) return Boolean is
3338    begin
3339       return Exists (System_Of (Typ));
3340    end Has_Dimension_System;
3341
3342    ------------------------------
3343    -- Is_Dim_IO_Package_Entity --
3344    ------------------------------
3345
3346    function Is_Dim_IO_Package_Entity (E : Entity_Id) return Boolean is
3347    begin
3348       --  Check the package entity corresponds to System.Dim.Float_IO or
3349       --  System.Dim.Integer_IO.
3350
3351       return
3352         Is_RTU (E, System_Dim_Float_IO)
3353           or else
3354         Is_RTU (E, System_Dim_Integer_IO);
3355    end Is_Dim_IO_Package_Entity;
3356
3357    -------------------------------------
3358    -- Is_Dim_IO_Package_Instantiation --
3359    -------------------------------------
3360
3361    function Is_Dim_IO_Package_Instantiation (N : Node_Id) return Boolean is
3362       Gen_Id : constant Node_Id := Name (N);
3363
3364    begin
3365       --  Check that the instantiated package is either System.Dim.Float_IO
3366       --  or System.Dim.Integer_IO.
3367
3368       return
3369         Is_Entity_Name (Gen_Id)
3370           and then Is_Dim_IO_Package_Entity (Entity (Gen_Id));
3371    end Is_Dim_IO_Package_Instantiation;
3372
3373    ----------------
3374    -- Is_Invalid --
3375    ----------------
3376
3377    function Is_Invalid (Position : Dimension_Position) return Boolean is
3378    begin
3379       return Position = Invalid_Position;
3380    end Is_Invalid;
3381
3382    ---------------------
3383    -- Move_Dimensions --
3384    ---------------------
3385
3386    procedure Move_Dimensions (From, To : Node_Id) is
3387    begin
3388       if Ada_Version < Ada_2012 then
3389          return;
3390       end if;
3391
3392       --  Copy the dimension of 'From to 'To' and remove dimension of 'From'
3393
3394       Copy_Dimensions   (From, To);
3395       Remove_Dimensions (From);
3396    end Move_Dimensions;
3397
3398    ------------
3399    -- Reduce --
3400    ------------
3401
3402    function Reduce (X : Rational) return Rational is
3403    begin
3404       if X.Numerator = 0 then
3405          return Zero;
3406       end if;
3407
3408       declare
3409          G : constant Int := GCD (X.Numerator, X.Denominator);
3410       begin
3411          return Rational'(Numerator =>   Whole (Int (X.Numerator)   / G),
3412                           Denominator => Whole (Int (X.Denominator) / G));
3413       end;
3414    end Reduce;
3415
3416    -----------------------
3417    -- Remove_Dimensions --
3418    -----------------------
3419
3420    procedure Remove_Dimensions (N : Node_Id) is
3421       Dims_Of_N : constant Dimension_Type := Dimensions_Of (N);
3422    begin
3423       if Exists (Dims_Of_N) then
3424          Dimension_Table.Remove (N);
3425       end if;
3426    end Remove_Dimensions;
3427
3428    -----------------------------------
3429    -- Remove_Dimension_In_Statement --
3430    -----------------------------------
3431
3432    --  Removal of dimension in statement as part of the Analyze_Statements
3433    --  routine (see package Sem_Ch5).
3434
3435    procedure Remove_Dimension_In_Statement (Stmt : Node_Id) is
3436    begin
3437       if Ada_Version < Ada_2012 then
3438          return;
3439       end if;
3440
3441       --  Remove dimension in parameter specifications for accept statement
3442
3443       if Nkind (Stmt) = N_Accept_Statement then
3444          declare
3445             Param : Node_Id := First (Parameter_Specifications (Stmt));
3446          begin
3447             while Present (Param) loop
3448                Remove_Dimensions (Param);
3449                Next (Param);
3450             end loop;
3451          end;
3452
3453       --  Remove dimension of name and expression in assignments
3454
3455       elsif Nkind (Stmt) = N_Assignment_Statement then
3456          Remove_Dimensions (Expression (Stmt));
3457          Remove_Dimensions (Name (Stmt));
3458       end if;
3459    end Remove_Dimension_In_Statement;
3460
3461    --------------------
3462    -- Set_Dimensions --
3463    --------------------
3464
3465    procedure Set_Dimensions (N : Node_Id; Val : Dimension_Type) is
3466    begin
3467       pragma Assert (OK_For_Dimension (Nkind (N)));
3468       pragma Assert (Exists (Val));
3469
3470       Dimension_Table.Set (N, Val);
3471    end Set_Dimensions;
3472
3473    ----------------
3474    -- Set_Symbol --
3475    ----------------
3476
3477    procedure Set_Symbol (E : Entity_Id; Val : String_Id) is
3478    begin
3479       Symbol_Table.Set (E, Val);
3480    end Set_Symbol;
3481
3482    ---------------------------------
3483    -- String_From_Numeric_Literal --
3484    ---------------------------------
3485
3486    function String_From_Numeric_Literal (N : Node_Id) return String_Id is
3487       Loc     : constant Source_Ptr        := Sloc (N);
3488       Sbuffer : constant Source_Buffer_Ptr :=
3489                   Source_Text (Get_Source_File_Index (Loc));
3490       Src_Ptr : Source_Ptr := Loc;
3491
3492       C : Character  := Sbuffer (Src_Ptr);
3493       --  Current source program character
3494
3495       function Belong_To_Numeric_Literal (C : Character) return Boolean;
3496       --  Return True if C belongs to a numeric literal
3497
3498       -------------------------------
3499       -- Belong_To_Numeric_Literal --
3500       -------------------------------
3501
3502       function Belong_To_Numeric_Literal (C : Character) return Boolean is
3503       begin
3504          case C is
3505             when '0' .. '9' |
3506                  '_'        |
3507                  '.'        |
3508                  'e'        |
3509                  '#'        |
3510                  'A'        |
3511                  'B'        |
3512                  'C'        |
3513                  'D'        |
3514                  'E'        |
3515                  'F'        =>
3516                return True;
3517
3518             --  Make sure '+' or '-' is part of an exponent.
3519
3520             when '+'  | '-' =>
3521                declare
3522                   Prev_C : constant Character := Sbuffer (Src_Ptr - 1);
3523                begin
3524                   return Prev_C = 'e' or else Prev_C = 'E';
3525                end;
3526
3527             --  All other character doesn't belong to a numeric literal
3528
3529             when others     =>
3530                return False;
3531          end case;
3532       end Belong_To_Numeric_Literal;
3533
3534    --  Start of processing for String_From_Numeric_Literal
3535
3536    begin
3537       Start_String;
3538       while Belong_To_Numeric_Literal (C) loop
3539          Store_String_Char (C);
3540          Src_Ptr := Src_Ptr + 1;
3541          C       := Sbuffer (Src_Ptr);
3542       end loop;
3543
3544       return End_String;
3545    end String_From_Numeric_Literal;
3546
3547    ---------------
3548    -- Symbol_Of --
3549    ---------------
3550
3551    function Symbol_Of (E : Entity_Id) return String_Id is
3552       Subtype_Symbol : constant String_Id := Symbol_Table.Get (E);
3553    begin
3554       if Subtype_Symbol /= No_String then
3555          return Subtype_Symbol;
3556       else
3557          return From_Dim_To_Str_Of_Unit_Symbols
3558                   (Dimensions_Of (E), System_Of (Base_Type (E)));
3559       end if;
3560    end Symbol_Of;
3561
3562    -----------------------
3563    -- Symbol_Table_Hash --
3564    -----------------------
3565
3566    function Symbol_Table_Hash (Key : Entity_Id) return Symbol_Table_Range is
3567    begin
3568       return Symbol_Table_Range (Key mod 511);
3569    end Symbol_Table_Hash;
3570
3571    ---------------
3572    -- System_Of --
3573    ---------------
3574
3575    function System_Of (E : Entity_Id) return System_Type is
3576       Type_Decl : constant Node_Id := Parent (E);
3577
3578    begin
3579       --  Look for Type_Decl in System_Table
3580
3581       for Dim_Sys in 1 .. System_Table.Last loop
3582          if Type_Decl = System_Table.Table (Dim_Sys).Type_Decl then
3583             return System_Table.Table (Dim_Sys);
3584          end if;
3585       end loop;
3586
3587       return Null_System;
3588    end System_Of;
3589
3590 end Sem_Dim;