1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              S E M _ D I M                               --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 2011-2019, 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
26with Aspects;  use Aspects;
27with Atree;    use Atree;
28with Einfo;    use Einfo;
29with Errout;   use Errout;
30with Exp_Util; use Exp_Util;
31with Lib;      use Lib;
32with Namet;    use Namet;
33with Nlists;   use Nlists;
34with Nmake;    use Nmake;
35with Opt;      use Opt;
36with Rtsfind;  use Rtsfind;
37with Sem;      use Sem;
38with Sem_Aux;  use Sem_Aux;
39with Sem_Eval; use Sem_Eval;
40with Sem_Res;  use Sem_Res;
41with Sem_Util; use Sem_Util;
42with Sinfo;    use Sinfo;
43with Sinput;   use Sinput;
44with Snames;   use Snames;
45with Stand;    use Stand;
46with Stringt;  use Stringt;
47with Table;
48with Tbuild;   use Tbuild;
49with Uintp;    use Uintp;
50with Urealp;   use Urealp;
51
52with GNAT.HTable;
53
54package body Sem_Dim is
55
56   -------------------------
57   -- Rational Arithmetic --
58   -------------------------
59
60   type Whole is new Int;
61   subtype Positive_Whole is Whole range 1 .. Whole'Last;
62
63   type Rational is record
64      Numerator   : Whole;
65      Denominator : Positive_Whole;
66   end record;
67
68   Zero : constant Rational := Rational'(Numerator =>   0,
69                                         Denominator => 1);
70
71   No_Rational : constant Rational := Rational'(Numerator =>   0,
72                                                Denominator => 2);
73   --  Used to indicate an expression that cannot be interpreted as a rational
74   --  Returned value of the Create_Rational_From routine when parameter Expr
75   --  is not a static representation of a rational.
76
77   --  Rational constructors
78
79   function "+" (Right : Whole) return Rational;
80   function GCD (Left, Right : Whole) return Int;
81   function Reduce (X : Rational) return Rational;
82
83   --  Unary operator for Rational
84
85   function "-" (Right : Rational) return Rational;
86   function "abs" (Right : Rational) return Rational;
87
88   --  Rational operations for Rationals
89
90   function "+" (Left, Right : Rational) return Rational;
91   function "-" (Left, Right : Rational) return Rational;
92   function "*" (Left, Right : Rational) return Rational;
93   function "/" (Left, Right : Rational) return Rational;
94
95   ------------------
96   -- System Types --
97   ------------------
98
99   Max_Number_Of_Dimensions : constant := 7;
100   --  Maximum number of dimensions in a dimension system
101
102   High_Position_Bound : constant := Max_Number_Of_Dimensions;
103   Invalid_Position    : constant := 0;
104   Low_Position_Bound  : constant := 1;
105
106   subtype Dimension_Position is
107     Nat range Invalid_Position .. High_Position_Bound;
108
109   type Name_Array is
110     array (Dimension_Position range
111              Low_Position_Bound .. High_Position_Bound) of Name_Id;
112   --  Store the names of all units within a system
113
114   No_Names : constant Name_Array := (others => No_Name);
115
116   type Symbol_Array is
117     array (Dimension_Position range
118              Low_Position_Bound .. High_Position_Bound) of String_Id;
119   --  Store the symbols of all units within a system
120
121   No_Symbols : constant Symbol_Array := (others => No_String);
122
123   --  The following record should be documented field by field
124
125   type System_Type is record
126      Type_Decl    : Node_Id;
127      Unit_Names   : Name_Array;
128      Unit_Symbols : Symbol_Array;
129      Dim_Symbols  : Symbol_Array;
130      Count        : Dimension_Position;
131   end record;
132
133   Null_System : constant System_Type :=
134                   (Empty, No_Names, No_Symbols, No_Symbols, Invalid_Position);
135
136   subtype System_Id is Nat;
137
138   --  The following table maps types to systems
139
140   package System_Table is new Table.Table (
141     Table_Component_Type => System_Type,
142     Table_Index_Type     => System_Id,
143     Table_Low_Bound      => 1,
144     Table_Initial        => 5,
145     Table_Increment      => 5,
146     Table_Name           => "System_Table");
147
148   --------------------
149   -- Dimension Type --
150   --------------------
151
152   type Dimension_Type is
153     array (Dimension_Position range
154              Low_Position_Bound .. High_Position_Bound) of Rational;
155
156   Null_Dimension : constant Dimension_Type := (others => Zero);
157
158   type Dimension_Table_Range is range 0 .. 510;
159   function Dimension_Table_Hash (Key : Node_Id) return Dimension_Table_Range;
160
161   --  The following table associates nodes with dimensions
162
163   package Dimension_Table is new
164     GNAT.HTable.Simple_HTable
165       (Header_Num => Dimension_Table_Range,
166        Element    => Dimension_Type,
167        No_Element => Null_Dimension,
168        Key        => Node_Id,
169        Hash       => Dimension_Table_Hash,
170        Equal      => "=");
171
172   ------------------
173   -- Symbol Types --
174   ------------------
175
176   type Symbol_Table_Range is range 0 .. 510;
177   function Symbol_Table_Hash (Key : Entity_Id) return Symbol_Table_Range;
178
179   --  Each subtype with a dimension has a symbolic representation of the
180   --  related unit. This table establishes a relation between the subtype
181   --  and the symbol.
182
183   package Symbol_Table is new
184     GNAT.HTable.Simple_HTable
185       (Header_Num => Symbol_Table_Range,
186        Element    => String_Id,
187        No_Element => No_String,
188        Key        => Entity_Id,
189        Hash       => Symbol_Table_Hash,
190        Equal      => "=");
191
192   --  The following array enumerates all contexts which may contain or
193   --  produce a dimension.
194
195   OK_For_Dimension : constant array (Node_Kind) of Boolean :=
196     (N_Attribute_Reference       => True,
197      N_Case_Expression           => True,
198      N_Expanded_Name             => True,
199      N_Explicit_Dereference      => True,
200      N_Defining_Identifier       => True,
201      N_Function_Call             => True,
202      N_Identifier                => True,
203      N_If_Expression             => True,
204      N_Indexed_Component         => True,
205      N_Integer_Literal           => True,
206      N_Op_Abs                    => True,
207      N_Op_Add                    => True,
208      N_Op_Divide                 => True,
209      N_Op_Expon                  => True,
210      N_Op_Minus                  => True,
211      N_Op_Mod                    => True,
212      N_Op_Multiply               => True,
213      N_Op_Plus                   => True,
214      N_Op_Rem                    => True,
215      N_Op_Subtract               => True,
216      N_Qualified_Expression      => True,
217      N_Real_Literal              => True,
218      N_Selected_Component        => True,
219      N_Slice                     => True,
220      N_Type_Conversion           => True,
221      N_Unchecked_Type_Conversion => True,
222
223      others                      => False);
224
225   -----------------------
226   -- Local Subprograms --
227   -----------------------
228
229   procedure Analyze_Dimension_Assignment_Statement (N : Node_Id);
230   --  Subroutine of Analyze_Dimension for assignment statement. Check that the
231   --  dimensions of the left-hand side and the right-hand side of N match.
232
233   procedure Analyze_Dimension_Binary_Op (N : Node_Id);
234   --  Subroutine of Analyze_Dimension for binary operators. Check the
235   --  dimensions of the right and the left operand permit the operation.
236   --  Then, evaluate the resulting dimensions for each binary operator.
237
238   procedure Analyze_Dimension_Component_Declaration (N : Node_Id);
239   --  Subroutine of Analyze_Dimension for component declaration. Check that
240   --  the dimensions of the type of N and of the expression match.
241
242   procedure Analyze_Dimension_Extended_Return_Statement (N : Node_Id);
243   --  Subroutine of Analyze_Dimension for extended return statement. Check
244   --  that the dimensions of the returned type and of the returned object
245   --  match.
246
247   procedure Analyze_Dimension_Has_Etype (N : Node_Id);
248   --  Subroutine of Analyze_Dimension for a subset of N_Has_Etype denoted by
249   --  the list below:
250   --    N_Attribute_Reference
251   --    N_Identifier
252   --    N_Indexed_Component
253   --    N_Qualified_Expression
254   --    N_Selected_Component
255   --    N_Slice
256   --    N_Type_Conversion
257   --    N_Unchecked_Type_Conversion
258
259   procedure Analyze_Dimension_Case_Expression (N : Node_Id);
260   --  Verify that all alternatives have the same dimension
261
262   procedure Analyze_Dimension_If_Expression (N : Node_Id);
263   --  Verify that all alternatives have the same dimension
264
265   procedure Analyze_Dimension_Number_Declaration (N : Node_Id);
266   --  Procedure to analyze dimension of expression in a number declaration.
267   --  This allows a named number to have nontrivial dimensions, while by
268   --  default a named number is dimensionless.
269
270   procedure Analyze_Dimension_Object_Declaration (N : Node_Id);
271   --  Subroutine of Analyze_Dimension for object declaration. Check that
272   --  the dimensions of the object type and the dimensions of the expression
273   --  (if expression is present) match. Note that when the expression is
274   --  a literal, no error is returned. This special case allows object
275   --  declaration such as: m : constant Length := 1.0;
276
277   procedure Analyze_Dimension_Object_Renaming_Declaration (N : Node_Id);
278   --  Subroutine of Analyze_Dimension for object renaming declaration. Check
279   --  the dimensions of the type and of the renamed object name of N match.
280
281   procedure Analyze_Dimension_Simple_Return_Statement (N : Node_Id);
282   --  Subroutine of Analyze_Dimension for simple return statement
283   --  Check that the dimensions of the returned type and of the returned
284   --  expression match.
285
286   procedure Analyze_Dimension_Subtype_Declaration (N : Node_Id);
287   --  Subroutine of Analyze_Dimension for subtype declaration. Propagate the
288   --  dimensions from the parent type to the identifier of N. Note that if
289   --  both the identifier and the parent type of N are not dimensionless,
290   --  return an error.
291
292   procedure Analyze_Dimension_Type_Conversion (N : Node_Id);
293   --  Type conversions handle conversions between literals and dimensioned
294   --  types, from dimensioned types to their base type, and between different
295   --  dimensioned systems. Dimensions of the conversion are obtained either
296   --  from those of the expression, or from the target type, and dimensional
297   --  consistency must be checked when converting between values belonging
298   --  to different dimensioned systems.
299
300   procedure Analyze_Dimension_Unary_Op (N : Node_Id);
301   --  Subroutine of Analyze_Dimension for unary operators. For Plus, Minus and
302   --  Abs operators, propagate the dimensions from the operand to N.
303
304   function Create_Rational_From
305     (Expr     : Node_Id;
306      Complain : Boolean) return Rational;
307   --  Given an arbitrary expression Expr, return a valid rational if Expr can
308   --  be interpreted as a rational. Otherwise return No_Rational and also an
309   --  error message if Complain is set to True.
310
311   function Dimensions_Of (N : Node_Id) return Dimension_Type;
312   --  Return the dimension vector of node N
313
314   function Dimensions_Msg_Of
315      (N                  : Node_Id;
316       Description_Needed : Boolean := False) return String;
317   --  Given a node N, return the dimension symbols of N, preceded by "has
318   --  dimension" if Description_Needed. if N is dimensionless, return "'[']",
319   --  or "is dimensionless" if Description_Needed.
320
321   function Dimension_System_Root (T : Entity_Id) return Entity_Id;
322   --  Given a type that has dimension information, return the type that is the
323   --  root of its dimension system, e.g. Mks_Type. If T is not a dimensioned
324   --  type, i.e. a standard numeric type, return Empty.
325
326   procedure Dim_Warning_For_Numeric_Literal (N : Node_Id; Typ : Entity_Id);
327   --  Issue a warning on the given numeric literal N to indicate that the
328   --  compiler made the assumption that the literal is not dimensionless
329   --  but has the dimension of Typ.
330
331   procedure Eval_Op_Expon_With_Rational_Exponent
332     (N              : Node_Id;
333      Exponent_Value : Rational);
334   --  Evaluate the exponent it is a rational and the operand has a dimension
335
336   function Exists (Dim : Dimension_Type) return Boolean;
337   --  Returns True iff Dim does not denote the null dimension
338
339   function Exists (Str : String_Id) return Boolean;
340   --  Returns True iff Str does not denote No_String
341
342   function Exists (Sys : System_Type) return Boolean;
343   --  Returns True iff Sys does not denote the null system
344
345   function From_Dim_To_Str_Of_Dim_Symbols
346     (Dims         : Dimension_Type;
347      System       : System_Type;
348      In_Error_Msg : Boolean := False) return String_Id;
349   --  Given a dimension vector and a dimension system, return the proper
350   --  string of dimension symbols. If In_Error_Msg is True (i.e. the String_Id
351   --  will be used to issue an error message) then this routine has a special
352   --  handling for the insertion characters * or [ which must be preceded by
353   --  a quote ' to be placed literally into the message.
354
355   function From_Dim_To_Str_Of_Unit_Symbols
356     (Dims   : Dimension_Type;
357      System : System_Type) return String_Id;
358   --  Given a dimension vector and a dimension system, return the proper
359   --  string of unit symbols.
360
361   function Is_Dim_IO_Package_Entity (E : Entity_Id) return Boolean;
362   --  Return True if E is the package entity of System.Dim.Float_IO or
363   --  System.Dim.Integer_IO.
364
365   function Is_Invalid (Position : Dimension_Position) return Boolean;
366   --  Return True if Pos denotes the invalid position
367
368   procedure Move_Dimensions (From : Node_Id; To : Node_Id);
369   --  Copy dimension vector of From to To and delete dimension vector of From
370
371   procedure Remove_Dimensions (N : Node_Id);
372   --  Remove the dimension vector of node N
373
374   procedure Set_Dimensions (N : Node_Id; Val : Dimension_Type);
375   --  Associate a dimension vector with a node
376
377   procedure Set_Symbol (E : Entity_Id; Val : String_Id);
378   --  Associate a symbol representation of a dimension vector with a subtype
379
380   function String_From_Numeric_Literal (N : Node_Id) return String_Id;
381   --  Return the string that corresponds to the numeric litteral N as it
382   --  appears in the source.
383
384   function Symbol_Of (E : Entity_Id) return String_Id;
385   --  E denotes a subtype with a dimension. Return the symbol representation
386   --  of the dimension vector.
387
388   function System_Of (E : Entity_Id) return System_Type;
389   --  E denotes a type, return associated system of the type if it has one
390
391   ---------
392   -- "+" --
393   ---------
394
395   function "+" (Right : Whole) return Rational is
396   begin
397      return Rational'(Numerator => Right, Denominator => 1);
398   end "+";
399
400   function "+" (Left, Right : Rational) return Rational is
401      R : constant Rational :=
402            Rational'(Numerator   => Left.Numerator   * Right.Denominator +
403                                     Left.Denominator * Right.Numerator,
404                      Denominator => Left.Denominator * Right.Denominator);
405   begin
406      return Reduce (R);
407   end "+";
408
409   ---------
410   -- "-" --
411   ---------
412
413   function "-" (Right : Rational) return Rational is
414   begin
415      return Rational'(Numerator   => -Right.Numerator,
416                       Denominator => Right.Denominator);
417   end "-";
418
419   function "-" (Left, Right : Rational) return Rational is
420      R : constant Rational :=
421            Rational'(Numerator   => Left.Numerator   * Right.Denominator -
422                                     Left.Denominator * Right.Numerator,
423                      Denominator => Left.Denominator * Right.Denominator);
424
425   begin
426      return Reduce (R);
427   end "-";
428
429   ---------
430   -- "*" --
431   ---------
432
433   function "*" (Left, Right : Rational) return Rational is
434      R : constant Rational :=
435            Rational'(Numerator   => Left.Numerator   * Right.Numerator,
436                      Denominator => Left.Denominator * Right.Denominator);
437   begin
438      return Reduce (R);
439   end "*";
440
441   ---------
442   -- "/" --
443   ---------
444
445   function "/" (Left, Right : Rational) return Rational is
446      R : constant Rational := abs Right;
447      L : Rational := Left;
448
449   begin
450      if Right.Numerator < 0 then
451         L.Numerator := Whole (-Integer (L.Numerator));
452      end if;
453
454      return Reduce (Rational'(Numerator   => L.Numerator   * R.Denominator,
455                               Denominator => L.Denominator * R.Numerator));
456   end "/";
457
458   -----------
459   -- "abs" --
460   -----------
461
462   function "abs" (Right : Rational) return Rational is
463   begin
464      return Rational'(Numerator   => abs Right.Numerator,
465                       Denominator => Right.Denominator);
466   end "abs";
467
468   ------------------------------
469   -- Analyze_Aspect_Dimension --
470   ------------------------------
471
472   --  with Dimension =>
473   --    ([Symbol =>] SYMBOL, DIMENSION_VALUE {, DIMENSION_Value})
474   --
475   --  SYMBOL ::= STRING_LITERAL | CHARACTER_LITERAL
476
477   --  DIMENSION_VALUE ::=
478   --    RATIONAL
479   --  | others               => RATIONAL
480   --  | DISCRETE_CHOICE_LIST => RATIONAL
481
482   --  RATIONAL ::= [-] NUMERIC_LITERAL [/ NUMERIC_LITERAL]
483
484   --  Note that when the dimensioned type is an integer type, then any
485   --  dimension value must be an integer literal.
486
487   procedure Analyze_Aspect_Dimension
488     (N    : Node_Id;
489      Id   : Entity_Id;
490      Aggr : Node_Id)
491   is
492      Def_Id : constant Entity_Id := Defining_Identifier (N);
493
494      Processed : array (Dimension_Type'Range) of Boolean := (others => False);
495      --  This array is used when processing ranges or Others_Choice as part of
496      --  the dimension aggregate.
497
498      Dimensions : Dimension_Type := Null_Dimension;
499
500      procedure Extract_Power
501        (Expr     : Node_Id;
502         Position : Dimension_Position);
503      --  Given an expression with denotes a rational number, read the number
504      --  and associate it with Position in Dimensions.
505
506      function Position_In_System
507        (Id     : Node_Id;
508         System : System_Type) return Dimension_Position;
509      --  Given an identifier which denotes a dimension, return the position of
510      --  that dimension within System.
511
512      -------------------
513      -- Extract_Power --
514      -------------------
515
516      procedure Extract_Power
517        (Expr     : Node_Id;
518         Position : Dimension_Position)
519      is
520      begin
521         Dimensions (Position) := Create_Rational_From (Expr, True);
522         Processed (Position) := True;
523
524         --  If the dimensioned root type is an integer type, it is not
525         --  particularly useful, and fractional dimensions do not make
526         --  much sense for such types, so previously we used to reject
527         --  dimensions of integer types that were not integer literals.
528         --  However, the manipulation of dimensions does not depend on
529         --  the kind of root type, so we can accept this usage for rare
530         --  cases where dimensions are specified for integer values.
531
532      end Extract_Power;
533
534      ------------------------
535      -- Position_In_System --
536      ------------------------
537
538      function Position_In_System
539        (Id     : Node_Id;
540         System : System_Type) return Dimension_Position
541      is
542         Dimension_Name : constant Name_Id := Chars (Id);
543
544      begin
545         for Position in System.Unit_Names'Range loop
546            if Dimension_Name = System.Unit_Names (Position) then
547               return Position;
548            end if;
549         end loop;
550
551         return Invalid_Position;
552      end Position_In_System;
553
554      --  Local variables
555
556      Assoc          : Node_Id;
557      Choice         : Node_Id;
558      Expr           : Node_Id;
559      Num_Choices    : Nat := 0;
560      Num_Dimensions : Nat := 0;
561      Others_Seen    : Boolean := False;
562      Position       : Nat := 0;
563      Sub_Ind        : Node_Id;
564      Symbol         : String_Id := No_String;
565      Symbol_Expr    : Node_Id;
566      System         : System_Type;
567      Typ            : Entity_Id;
568
569      Errors_Count : Nat;
570      --  Errors_Count is a count of errors detected by the compiler so far
571      --  just before the extraction of symbol, names and values in the
572      --  aggregate (Step 2).
573      --
574      --  At the end of the analysis, there is a check to verify that this
575      --  count equals to Serious_Errors_Detected i.e. no erros have been
576      --  encountered during the process. Otherwise the Dimension_Table is
577      --  not filled.
578
579   --  Start of processing for Analyze_Aspect_Dimension
580
581   begin
582      --  STEP 1: Legality of aspect
583
584      if Nkind (N) /= N_Subtype_Declaration then
585         Error_Msg_NE ("aspect& must apply to subtype declaration", N, Id);
586         return;
587      end if;
588
589      Sub_Ind := Subtype_Indication (N);
590      Typ := Etype (Sub_Ind);
591      System := System_Of (Typ);
592
593      if Nkind (Sub_Ind) = N_Subtype_Indication then
594         Error_Msg_NE
595           ("constraint not allowed with aspect&", Constraint (Sub_Ind), Id);
596         return;
597      end if;
598
599      --  The dimension declarations are useless if the parent type does not
600      --  declare a valid system.
601
602      if not Exists (System) then
603         Error_Msg_NE
604           ("parent type of& lacks dimension system", Sub_Ind, Def_Id);
605         return;
606      end if;
607
608      if Nkind (Aggr) /= N_Aggregate then
609         Error_Msg_N ("aggregate expected", Aggr);
610         return;
611      end if;
612
613      --  STEP 2: Symbol, Names and values extraction
614
615      --  Get the number of errors detected by the compiler so far
616
617      Errors_Count := Serious_Errors_Detected;
618
619      --  STEP 2a: Symbol extraction
620
621      --  The first entry in the aggregate may be the symbolic representation
622      --  of the quantity.
623
624      --  Positional symbol argument
625
626      Symbol_Expr := First (Expressions (Aggr));
627
628      --  Named symbol argument
629
630      if No (Symbol_Expr)
631        or else not Nkind_In (Symbol_Expr, N_Character_Literal,
632                                           N_String_Literal)
633      then
634         Symbol_Expr := Empty;
635
636         --  Component associations present
637
638         if Present (Component_Associations (Aggr)) then
639            Assoc  := First (Component_Associations (Aggr));
640            Choice := First (Choices (Assoc));
641
642            if No (Next (Choice)) and then Nkind (Choice) = N_Identifier then
643
644               --  Symbol component association is present
645
646               if Chars (Choice) = Name_Symbol then
647                  Num_Choices := Num_Choices + 1;
648                  Symbol_Expr := Expression (Assoc);
649
650                  --  Verify symbol expression is a string or a character
651
652                  if not Nkind_In (Symbol_Expr, N_Character_Literal,
653                                                N_String_Literal)
654                  then
655                     Symbol_Expr := Empty;
656                     Error_Msg_N
657                       ("symbol expression must be character or string",
658                        Symbol_Expr);
659                  end if;
660
661               --  Special error if no Symbol choice but expression is string
662               --  or character.
663
664               elsif Nkind_In (Expression (Assoc), N_Character_Literal,
665                                                   N_String_Literal)
666               then
667                  Num_Choices := Num_Choices + 1;
668                  Error_Msg_N
669                    ("optional component Symbol expected, found&", Choice);
670               end if;
671            end if;
672         end if;
673      end if;
674
675      --  STEP 2b: Names and values extraction
676
677      --  Positional elements
678
679      Expr := First (Expressions (Aggr));
680
681      --  Skip the symbol expression when present
682
683      if Present (Symbol_Expr) and then Num_Choices = 0 then
684         Expr := Next (Expr);
685      end if;
686
687      Position := Low_Position_Bound;
688      while Present (Expr) loop
689         if Position > High_Position_Bound then
690            Error_Msg_N
691              ("type& has more dimensions than system allows", Def_Id);
692            exit;
693         end if;
694
695         Extract_Power (Expr, Position);
696
697         Position := Position + 1;
698         Num_Dimensions := Num_Dimensions + 1;
699
700         Next (Expr);
701      end loop;
702
703      --  Named elements
704
705      Assoc := First (Component_Associations (Aggr));
706
707      --  Skip the symbol association when present
708
709      if Num_Choices = 1 then
710         Next (Assoc);
711      end if;
712
713      while Present (Assoc) loop
714         Expr := Expression (Assoc);
715
716         Choice := First (Choices (Assoc));
717         while Present (Choice) loop
718
719            --  Identifier case: NAME => EXPRESSION
720
721            if Nkind (Choice) = N_Identifier then
722               Position := Position_In_System (Choice, System);
723
724               if Is_Invalid (Position) then
725                  Error_Msg_N ("dimension name& not part of system", Choice);
726               else
727                  Extract_Power (Expr, Position);
728               end if;
729
730            --  Range case: NAME .. NAME => EXPRESSION
731
732            elsif Nkind (Choice) = N_Range then
733               declare
734                  Low      : constant Node_Id := Low_Bound (Choice);
735                  High     : constant Node_Id := High_Bound (Choice);
736                  Low_Pos  : Dimension_Position;
737                  High_Pos : Dimension_Position;
738
739               begin
740                  if Nkind (Low) /= N_Identifier then
741                     Error_Msg_N ("bound must denote a dimension name", Low);
742
743                  elsif Nkind (High) /= N_Identifier then
744                     Error_Msg_N ("bound must denote a dimension name", High);
745
746                  else
747                     Low_Pos  := Position_In_System (Low, System);
748                     High_Pos := Position_In_System (High, System);
749
750                     if Is_Invalid (Low_Pos) then
751                        Error_Msg_N ("dimension name& not part of system",
752                                     Low);
753
754                     elsif Is_Invalid (High_Pos) then
755                        Error_Msg_N ("dimension name& not part of system",
756                                     High);
757
758                     elsif Low_Pos > High_Pos then
759                        Error_Msg_N ("expected low to high range", Choice);
760
761                     else
762                        for Position in Low_Pos .. High_Pos loop
763                           Extract_Power (Expr, Position);
764                        end loop;
765                     end if;
766                  end if;
767               end;
768
769            --  Others case: OTHERS => EXPRESSION
770
771            elsif Nkind (Choice) = N_Others_Choice then
772               if Present (Next (Choice)) or else Present (Prev (Choice)) then
773                  Error_Msg_N
774                    ("OTHERS must appear alone in a choice list", Choice);
775
776               elsif Present (Next (Assoc)) then
777                  Error_Msg_N
778                    ("OTHERS must appear last in an aggregate", Choice);
779
780               elsif Others_Seen then
781                  Error_Msg_N ("multiple OTHERS not allowed", Choice);
782
783               else
784                  --  Fill the non-processed dimensions with the default value
785                  --  supplied by others.
786
787                  for Position in Processed'Range loop
788                     if not Processed (Position) then
789                        Extract_Power (Expr, Position);
790                     end if;
791                  end loop;
792               end if;
793
794               Others_Seen := True;
795
796            --  All other cases are illegal declarations of dimension names
797
798            else
799               Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
800            end if;
801
802            Num_Choices := Num_Choices + 1;
803            Next (Choice);
804         end loop;
805
806         Num_Dimensions := Num_Dimensions + 1;
807         Next (Assoc);
808      end loop;
809
810      --  STEP 3: Consistency of system and dimensions
811
812      if Present (First (Expressions (Aggr)))
813        and then (First (Expressions (Aggr)) /= Symbol_Expr
814                   or else Present (Next (Symbol_Expr)))
815        and then (Num_Choices > 1
816                   or else (Num_Choices = 1 and then not Others_Seen))
817      then
818         Error_Msg_N
819           ("named associations cannot follow positional associations", Aggr);
820      end if;
821
822      if Num_Dimensions > System.Count then
823         Error_Msg_N ("type& has more dimensions than system allows", Def_Id);
824
825      elsif Num_Dimensions < System.Count and then not Others_Seen then
826         Error_Msg_N ("type& has less dimensions than system allows", Def_Id);
827      end if;
828
829      --  STEP 4: Dimension symbol extraction
830
831      if Present (Symbol_Expr) then
832         if Nkind (Symbol_Expr) = N_Character_Literal then
833            Start_String;
834            Store_String_Char (UI_To_CC (Char_Literal_Value (Symbol_Expr)));
835            Symbol := End_String;
836
837         else
838            Symbol := Strval (Symbol_Expr);
839         end if;
840
841         if String_Length (Symbol) = 0 then
842            Error_Msg_N ("empty string not allowed here", Symbol_Expr);
843         end if;
844      end if;
845
846      --  STEP 5: Storage of extracted values
847
848      --  Check that no errors have been detected during the analysis
849
850      if Errors_Count = Serious_Errors_Detected then
851
852         --  Check for useless declaration
853
854         if Symbol = No_String and then not Exists (Dimensions) then
855            Error_Msg_N ("useless dimension declaration", Aggr);
856         end if;
857
858         if Symbol /= No_String then
859            Set_Symbol (Def_Id, Symbol);
860         end if;
861
862         if Exists (Dimensions) then
863            Set_Dimensions (Def_Id, Dimensions);
864         end if;
865      end if;
866   end Analyze_Aspect_Dimension;
867
868   -------------------------------------
869   -- Analyze_Aspect_Dimension_System --
870   -------------------------------------
871
872   --  with Dimension_System => (DIMENSION {, DIMENSION});
873
874   --  DIMENSION ::= (
875   --    [Unit_Name   =>] IDENTIFIER,
876   --    [Unit_Symbol =>] SYMBOL,
877   --    [Dim_Symbol  =>] SYMBOL)
878
879   procedure Analyze_Aspect_Dimension_System
880     (N    : Node_Id;
881      Id   : Entity_Id;
882      Aggr : Node_Id)
883   is
884      function Is_Derived_Numeric_Type (N : Node_Id) return Boolean;
885      --  Determine whether type declaration N denotes a numeric derived type
886
887      -------------------------------
888      -- Is_Derived_Numeric_Type --
889      -------------------------------
890
891      function Is_Derived_Numeric_Type (N : Node_Id) return Boolean is
892      begin
893         return
894           Nkind (N) = N_Full_Type_Declaration
895             and then Nkind (Type_Definition (N)) = N_Derived_Type_Definition
896             and then Is_Numeric_Type
897                        (Entity (Subtype_Indication (Type_Definition (N))));
898      end Is_Derived_Numeric_Type;
899
900      --  Local variables
901
902      Assoc        : Node_Id;
903      Choice       : Node_Id;
904      Dim_Aggr     : Node_Id;
905      Dim_Symbol   : Node_Id;
906      Dim_Symbols  : Symbol_Array       := No_Symbols;
907      Dim_System   : System_Type        := Null_System;
908      Position     : Dimension_Position := Invalid_Position;
909      Unit_Name    : Node_Id;
910      Unit_Names   : Name_Array         := No_Names;
911      Unit_Symbol  : Node_Id;
912      Unit_Symbols : Symbol_Array       := No_Symbols;
913
914      Errors_Count : Nat;
915      --  Errors_Count is a count of errors detected by the compiler so far
916      --  just before the extraction of names and symbols in the aggregate
917      --  (Step 3).
918      --
919      --  At the end of the analysis, there is a check to verify that this
920      --  count equals Serious_Errors_Detected i.e. no errors have been
921      --  encountered during the process. Otherwise the System_Table is
922      --  not filled.
923
924   --  Start of processing for Analyze_Aspect_Dimension_System
925
926   begin
927      --  STEP 1: Legality of aspect
928
929      if not Is_Derived_Numeric_Type (N) then
930         Error_Msg_NE
931           ("aspect& must apply to numeric derived type declaration", N, Id);
932         return;
933      end if;
934
935      if Nkind (Aggr) /= N_Aggregate then
936         Error_Msg_N ("aggregate expected", Aggr);
937         return;
938      end if;
939
940      --  STEP 2: Structural verification of the dimension aggregate
941
942      if Present (Component_Associations (Aggr)) then
943         Error_Msg_N ("expected positional aggregate", Aggr);
944         return;
945      end if;
946
947      --  STEP 3: Name and Symbol extraction
948
949      Dim_Aggr     := First (Expressions (Aggr));
950      Errors_Count := Serious_Errors_Detected;
951      while Present (Dim_Aggr) loop
952         if Position = High_Position_Bound then
953            Error_Msg_N ("too many dimensions in system", Aggr);
954            exit;
955         end if;
956
957         Position := Position + 1;
958
959         if Nkind (Dim_Aggr) /= N_Aggregate then
960            Error_Msg_N ("aggregate expected", Dim_Aggr);
961
962         else
963            if Present (Component_Associations (Dim_Aggr))
964              and then Present (Expressions (Dim_Aggr))
965            then
966               Error_Msg_N
967                 ("mixed positional/named aggregate not allowed here",
968                  Dim_Aggr);
969
970            --  Verify each dimension aggregate has three arguments
971
972            elsif List_Length (Component_Associations (Dim_Aggr)) /= 3
973              and then List_Length (Expressions (Dim_Aggr)) /= 3
974            then
975               Error_Msg_N
976                 ("three components expected in aggregate", Dim_Aggr);
977
978            else
979               --  Named dimension aggregate
980
981               if Present (Component_Associations (Dim_Aggr)) then
982
983                  --  Check first argument denotes the unit name
984
985                  Assoc     := First (Component_Associations (Dim_Aggr));
986                  Choice    := First (Choices (Assoc));
987                  Unit_Name := Expression (Assoc);
988
989                  if Present (Next (Choice))
990                    or else Nkind (Choice) /= N_Identifier
991                  then
992                     Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
993
994                  elsif Chars (Choice) /= Name_Unit_Name then
995                     Error_Msg_N ("expected Unit_Name, found&", Choice);
996                  end if;
997
998                  --  Check the second argument denotes the unit symbol
999
1000                  Next (Assoc);
1001                  Choice      := First (Choices (Assoc));
1002                  Unit_Symbol := Expression (Assoc);
1003
1004                  if Present (Next (Choice))
1005                    or else Nkind (Choice) /= N_Identifier
1006                  then
1007                     Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
1008
1009                  elsif Chars (Choice) /= Name_Unit_Symbol then
1010                     Error_Msg_N ("expected Unit_Symbol, found&", Choice);
1011                  end if;
1012
1013                  --  Check the third argument denotes the dimension symbol
1014
1015                  Next (Assoc);
1016                  Choice     := First (Choices (Assoc));
1017                  Dim_Symbol := Expression (Assoc);
1018
1019                  if Present (Next (Choice))
1020                    or else Nkind (Choice) /= N_Identifier
1021                  then
1022                     Error_Msg_NE ("wrong syntax for aspect&", Choice, Id);
1023                  elsif Chars (Choice) /= Name_Dim_Symbol then
1024                     Error_Msg_N ("expected Dim_Symbol, found&", Choice);
1025                  end if;
1026
1027               --  Positional dimension aggregate
1028
1029               else
1030                  Unit_Name   := First (Expressions (Dim_Aggr));
1031                  Unit_Symbol := Next (Unit_Name);
1032                  Dim_Symbol  := Next (Unit_Symbol);
1033               end if;
1034
1035               --  Check the first argument for each dimension aggregate is
1036               --  a name.
1037
1038               if Nkind (Unit_Name) = N_Identifier then
1039                  Unit_Names (Position) := Chars (Unit_Name);
1040               else
1041                  Error_Msg_N ("expected unit name", Unit_Name);
1042               end if;
1043
1044               --  Check the second argument for each dimension aggregate is
1045               --  a string or a character.
1046
1047               if not Nkind_In (Unit_Symbol, N_String_Literal,
1048                                             N_Character_Literal)
1049               then
1050                  Error_Msg_N
1051                    ("expected unit symbol (string or character)",
1052                     Unit_Symbol);
1053
1054               else
1055                  --  String case
1056
1057                  if Nkind (Unit_Symbol) = N_String_Literal then
1058                     Unit_Symbols (Position) := Strval (Unit_Symbol);
1059
1060                  --  Character case
1061
1062                  else
1063                     Start_String;
1064                     Store_String_Char
1065                       (UI_To_CC (Char_Literal_Value (Unit_Symbol)));
1066                     Unit_Symbols (Position) := End_String;
1067                  end if;
1068
1069                  --  Verify that the string is not empty
1070
1071                  if String_Length (Unit_Symbols (Position)) = 0 then
1072                     Error_Msg_N
1073                       ("empty string not allowed here", Unit_Symbol);
1074                  end if;
1075               end if;
1076
1077               --  Check the third argument for each dimension aggregate is
1078               --  a string or a character.
1079
1080               if not Nkind_In (Dim_Symbol, N_String_Literal,
1081                                            N_Character_Literal)
1082               then
1083                  Error_Msg_N
1084                    ("expected dimension symbol (string or character)",
1085                     Dim_Symbol);
1086
1087               else
1088                  --  String case
1089
1090                  if Nkind (Dim_Symbol) = N_String_Literal then
1091                     Dim_Symbols (Position) := Strval (Dim_Symbol);
1092
1093                  --  Character case
1094
1095                  else
1096                     Start_String;
1097                     Store_String_Char
1098                       (UI_To_CC (Char_Literal_Value (Dim_Symbol)));
1099                     Dim_Symbols (Position) := End_String;
1100                  end if;
1101
1102                  --  Verify that the string is not empty
1103
1104                  if String_Length (Dim_Symbols (Position)) = 0 then
1105                     Error_Msg_N ("empty string not allowed here", Dim_Symbol);
1106                  end if;
1107               end if;
1108            end if;
1109         end if;
1110
1111         Next (Dim_Aggr);
1112      end loop;
1113
1114      --  STEP 4: Storage of extracted values
1115
1116      --  Check that no errors have been detected during the analysis
1117
1118      if Errors_Count = Serious_Errors_Detected then
1119         Dim_System.Type_Decl    := N;
1120         Dim_System.Unit_Names   := Unit_Names;
1121         Dim_System.Unit_Symbols := Unit_Symbols;
1122         Dim_System.Dim_Symbols  := Dim_Symbols;
1123         Dim_System.Count        := Position;
1124         System_Table.Append (Dim_System);
1125      end if;
1126   end Analyze_Aspect_Dimension_System;
1127
1128   -----------------------
1129   -- Analyze_Dimension --
1130   -----------------------
1131
1132   --  This dispatch routine propagates dimensions for each node
1133
1134   procedure Analyze_Dimension (N : Node_Id) is
1135   begin
1136      --  Aspect is an Ada 2012 feature. Note that there is no need to check
1137      --  dimensions for nodes that don't come from source, except for subtype
1138      --  declarations where the dimensions are inherited from the base type,
1139      --  for explicit dereferences generated when expanding iterators, and
1140      --  for object declarations generated for inlining.
1141
1142      if Ada_Version < Ada_2012 then
1143         return;
1144
1145      --  Inlined bodies have already been checked for dimensionality
1146
1147      elsif In_Inlined_Body then
1148         return;
1149
1150      elsif not Comes_From_Source (N) then
1151         if Nkind_In (N, N_Explicit_Dereference,
1152                         N_Identifier,
1153                         N_Object_Declaration,
1154                         N_Subtype_Declaration)
1155         then
1156            null;
1157         else
1158            return;
1159         end if;
1160      end if;
1161
1162      case Nkind (N) is
1163         when N_Assignment_Statement =>
1164            Analyze_Dimension_Assignment_Statement (N);
1165
1166         when N_Binary_Op =>
1167            Analyze_Dimension_Binary_Op (N);
1168
1169         when N_Case_Expression =>
1170            Analyze_Dimension_Case_Expression (N);
1171
1172         when N_Component_Declaration =>
1173            Analyze_Dimension_Component_Declaration (N);
1174
1175         when N_Extended_Return_Statement =>
1176            Analyze_Dimension_Extended_Return_Statement (N);
1177
1178         when N_Attribute_Reference
1179            | N_Expanded_Name
1180            | N_Explicit_Dereference
1181            | N_Function_Call
1182            | N_Indexed_Component
1183            | N_Qualified_Expression
1184            | N_Selected_Component
1185            | N_Slice
1186            | N_Unchecked_Type_Conversion
1187         =>
1188            Analyze_Dimension_Has_Etype (N);
1189
1190         --  In the presence of a repaired syntax error, an identifier may be
1191         --  introduced without a usable type.
1192
1193         when N_Identifier =>
1194            if Present (Etype (N)) then
1195               Analyze_Dimension_Has_Etype (N);
1196            end if;
1197
1198         when N_If_Expression =>
1199            Analyze_Dimension_If_Expression (N);
1200
1201         when N_Number_Declaration =>
1202            Analyze_Dimension_Number_Declaration (N);
1203
1204         when N_Object_Declaration =>
1205            Analyze_Dimension_Object_Declaration (N);
1206
1207         when N_Object_Renaming_Declaration =>
1208            Analyze_Dimension_Object_Renaming_Declaration (N);
1209
1210         when N_Simple_Return_Statement =>
1211            if not Comes_From_Extended_Return_Statement (N) then
1212               Analyze_Dimension_Simple_Return_Statement (N);
1213            end if;
1214
1215         when N_Subtype_Declaration =>
1216            Analyze_Dimension_Subtype_Declaration (N);
1217
1218         when  N_Type_Conversion =>
1219            Analyze_Dimension_Type_Conversion (N);
1220
1221         when N_Unary_Op =>
1222            Analyze_Dimension_Unary_Op (N);
1223
1224         when others =>
1225            null;
1226      end case;
1227   end Analyze_Dimension;
1228
1229   ---------------------------------------
1230   -- Analyze_Dimension_Array_Aggregate --
1231   ---------------------------------------
1232
1233   procedure Analyze_Dimension_Array_Aggregate
1234     (N        : Node_Id;
1235      Comp_Typ : Entity_Id)
1236   is
1237      Comp_Ass         : constant List_Id        := Component_Associations (N);
1238      Dims_Of_Comp_Typ : constant Dimension_Type := Dimensions_Of (Comp_Typ);
1239      Exps             : constant List_Id        := Expressions (N);
1240
1241      Comp         : Node_Id;
1242      Dims_Of_Expr : Dimension_Type;
1243      Expr         : Node_Id;
1244
1245      Error_Detected : Boolean := False;
1246      --  This flag is used in order to indicate if an error has been detected
1247      --  so far by the compiler in this routine.
1248
1249   begin
1250      --  Aspect is an Ada 2012 feature. Nothing to do here if the component
1251      --  base type is not a dimensioned type.
1252
1253      --  Inlined bodies have already been checked for dimensionality.
1254
1255      --  Note that here the original node must come from source since the
1256      --  original array aggregate may not have been entirely decorated.
1257
1258      if Ada_Version < Ada_2012
1259        or else In_Inlined_Body
1260        or else not Comes_From_Source (Original_Node (N))
1261        or else not Has_Dimension_System (Base_Type (Comp_Typ))
1262      then
1263         return;
1264      end if;
1265
1266      --  Check whether there is any positional component association
1267
1268      if Is_Empty_List (Exps) then
1269         Comp := First (Comp_Ass);
1270      else
1271         Comp := First (Exps);
1272      end if;
1273
1274      while Present (Comp) loop
1275
1276         --  Get the expression from the component
1277
1278         if Nkind (Comp) = N_Component_Association then
1279            Expr := Expression (Comp);
1280         else
1281            Expr := Comp;
1282         end if;
1283
1284         --  Issue an error if the dimensions of the component type and the
1285         --  dimensions of the component mismatch.
1286
1287         --  Note that we must ensure the expression has been fully analyzed
1288         --  since it may not be decorated at this point. We also don't want to
1289         --  issue the same error message multiple times on the same expression
1290         --  (may happen when an aggregate is converted into a positional
1291         --  aggregate). We also must verify that this is a scalar component,
1292         --  and not a subaggregate of a multidimensional aggregate.
1293         --  The expression may be an identifier that has been copied several
1294         --  times during expansion, its dimensions are those of its type.
1295
1296         if Is_Entity_Name (Expr) then
1297            Dims_Of_Expr := Dimensions_Of (Etype (Expr));
1298         else
1299            Dims_Of_Expr := Dimensions_Of (Expr);
1300         end if;
1301
1302         if Comes_From_Source (Original_Node (Expr))
1303           and then Present (Etype (Expr))
1304           and then Is_Numeric_Type (Etype (Expr))
1305           and then Dims_Of_Expr /= Dims_Of_Comp_Typ
1306           and then Sloc (Comp) /= Sloc (Prev (Comp))
1307         then
1308            --  Check if an error has already been encountered so far
1309
1310            if not Error_Detected then
1311               Error_Msg_N ("dimensions mismatch in array aggregate", N);
1312               Error_Detected := True;
1313            end if;
1314
1315            Error_Msg_N
1316              ("\expected dimension " & Dimensions_Msg_Of (Comp_Typ)
1317               & ", found " & Dimensions_Msg_Of (Expr), Expr);
1318         end if;
1319
1320         --  Look at the named components right after the positional components
1321
1322         if not Present (Next (Comp))
1323           and then List_Containing (Comp) = Exps
1324         then
1325            Comp := First (Comp_Ass);
1326         else
1327            Next (Comp);
1328         end if;
1329      end loop;
1330   end Analyze_Dimension_Array_Aggregate;
1331
1332   --------------------------------------------
1333   -- Analyze_Dimension_Assignment_Statement --
1334   --------------------------------------------
1335
1336   procedure Analyze_Dimension_Assignment_Statement (N : Node_Id) is
1337      Lhs         : constant Node_Id := Name (N);
1338      Dims_Of_Lhs : constant Dimension_Type := Dimensions_Of (Lhs);
1339      Rhs         : constant Node_Id := Expression (N);
1340      Dims_Of_Rhs : constant Dimension_Type := Dimensions_Of (Rhs);
1341
1342      procedure Error_Dim_Msg_For_Assignment_Statement
1343        (N   : Node_Id;
1344         Lhs : Node_Id;
1345         Rhs : Node_Id);
1346      --  Error using Error_Msg_N at node N. Output the dimensions of left
1347      --  and right hand sides.
1348
1349      --------------------------------------------
1350      -- Error_Dim_Msg_For_Assignment_Statement --
1351      --------------------------------------------
1352
1353      procedure Error_Dim_Msg_For_Assignment_Statement
1354        (N   : Node_Id;
1355         Lhs : Node_Id;
1356         Rhs : Node_Id)
1357      is
1358      begin
1359         Error_Msg_N ("dimensions mismatch in assignment", N);
1360         Error_Msg_N ("\left-hand side "  & Dimensions_Msg_Of (Lhs, True), N);
1361         Error_Msg_N ("\right-hand side " & Dimensions_Msg_Of (Rhs, True), N);
1362      end Error_Dim_Msg_For_Assignment_Statement;
1363
1364   --  Start of processing for Analyze_Dimension_Assignment
1365
1366   begin
1367      if Dims_Of_Lhs /= Dims_Of_Rhs then
1368         Error_Dim_Msg_For_Assignment_Statement (N, Lhs, Rhs);
1369      end if;
1370   end Analyze_Dimension_Assignment_Statement;
1371
1372   ---------------------------------
1373   -- Analyze_Dimension_Binary_Op --
1374   ---------------------------------
1375
1376   --  Check and propagate the dimensions for binary operators
1377   --  Note that when the dimensions mismatch, no dimension is propagated to N.
1378
1379   procedure Analyze_Dimension_Binary_Op (N : Node_Id) is
1380      N_Kind : constant Node_Kind := Nkind (N);
1381
1382      function Dimensions_Of_Operand (N : Node_Id) return Dimension_Type;
1383      --  If the operand is a numeric literal that comes from a declared
1384      --  constant, use the dimensions of the constant which were computed
1385      --  from the expression of the constant declaration. Otherwise the
1386      --  dimensions are those of the operand, or the type of the operand.
1387      --  This takes care of node rewritings from validity checks, where the
1388      --  dimensions of the operand itself may not be preserved, while the
1389      --  type comes from context and must have dimension information.
1390
1391      procedure Error_Dim_Msg_For_Binary_Op (N, L, R : Node_Id);
1392      --  Error using Error_Msg_NE and Error_Msg_N at node N. Output the
1393      --  dimensions of both operands.
1394
1395      ---------------------------
1396      -- Dimensions_Of_Operand --
1397      ---------------------------
1398
1399      function Dimensions_Of_Operand (N : Node_Id) return Dimension_Type is
1400         Dims : constant Dimension_Type := Dimensions_Of (N);
1401
1402      begin
1403         if Exists (Dims) then
1404            return Dims;
1405
1406         elsif Is_Entity_Name (N) then
1407            return Dimensions_Of (Etype (Entity (N)));
1408
1409         elsif Nkind (N) = N_Real_Literal then
1410
1411            if Present (Original_Entity (N)) then
1412               return Dimensions_Of (Original_Entity (N));
1413
1414            else
1415               return Dimensions_Of (Etype (N));
1416            end if;
1417
1418         --  Otherwise return the default dimensions
1419
1420         else
1421            return Dims;
1422         end if;
1423      end Dimensions_Of_Operand;
1424
1425      ---------------------------------
1426      -- Error_Dim_Msg_For_Binary_Op --
1427      ---------------------------------
1428
1429      procedure Error_Dim_Msg_For_Binary_Op (N, L, R : Node_Id) is
1430      begin
1431         Error_Msg_NE
1432           ("both operands for operation& must have same dimensions",
1433            N, Entity (N));
1434         Error_Msg_N ("\left operand "  & Dimensions_Msg_Of (L, True), N);
1435         Error_Msg_N ("\right operand " & Dimensions_Msg_Of (R, True), N);
1436      end Error_Dim_Msg_For_Binary_Op;
1437
1438   --  Start of processing for Analyze_Dimension_Binary_Op
1439
1440   begin
1441      --  If the node is already analyzed, do not examine the operands. At the
1442      --  end of the analysis their dimensions have been removed, and the node
1443      --  itself may have been rewritten.
1444
1445      if Analyzed (N) then
1446         return;
1447      end if;
1448
1449      if Nkind_In (N_Kind, N_Op_Add, N_Op_Expon, N_Op_Subtract)
1450        or else N_Kind in N_Multiplying_Operator
1451        or else N_Kind in N_Op_Compare
1452      then
1453         declare
1454            L                : constant Node_Id        := Left_Opnd (N);
1455            Dims_Of_L        : constant Dimension_Type :=
1456                                 Dimensions_Of_Operand (L);
1457            L_Has_Dimensions : constant Boolean        := Exists (Dims_Of_L);
1458            R                : constant Node_Id        := Right_Opnd (N);
1459            Dims_Of_R        : constant Dimension_Type :=
1460                                 Dimensions_Of_Operand (R);
1461            R_Has_Dimensions : constant Boolean        := Exists (Dims_Of_R);
1462            Dims_Of_N        : Dimension_Type          := Null_Dimension;
1463
1464         begin
1465            --  N_Op_Add, N_Op_Mod, N_Op_Rem or N_Op_Subtract case
1466
1467            if Nkind_In (N, N_Op_Add, N_Op_Mod, N_Op_Rem, N_Op_Subtract) then
1468
1469               --  Check both operands have same dimension
1470
1471               if Dims_Of_L /= Dims_Of_R then
1472                  Error_Dim_Msg_For_Binary_Op (N, L, R);
1473               else
1474                  --  Check both operands are not dimensionless
1475
1476                  if Exists (Dims_Of_L) then
1477                     Set_Dimensions (N, Dims_Of_L);
1478                  end if;
1479               end if;
1480
1481            --  N_Op_Multiply or N_Op_Divide case
1482
1483            elsif Nkind_In (N_Kind, N_Op_Multiply, N_Op_Divide) then
1484
1485               --  Check at least one operand is not dimensionless
1486
1487               if L_Has_Dimensions or R_Has_Dimensions then
1488
1489                  --  Multiplication case
1490
1491                  --  Get both operands dimensions and add them
1492
1493                  if N_Kind = N_Op_Multiply then
1494                     for Position in Dimension_Type'Range loop
1495                        Dims_Of_N (Position) :=
1496                          Dims_Of_L (Position) + Dims_Of_R (Position);
1497                     end loop;
1498
1499                  --  Division case
1500
1501                  --  Get both operands dimensions and subtract them
1502
1503                  else
1504                     for Position in Dimension_Type'Range loop
1505                        Dims_Of_N (Position) :=
1506                          Dims_Of_L (Position) - Dims_Of_R (Position);
1507                     end loop;
1508                  end if;
1509
1510                  if Exists (Dims_Of_N) then
1511                     Set_Dimensions (N, Dims_Of_N);
1512                  end if;
1513               end if;
1514
1515            --  Exponentiation case
1516
1517            --  Note: a rational exponent is allowed for dimensioned operand
1518
1519            elsif N_Kind = N_Op_Expon then
1520
1521               --  Check the left operand is not dimensionless. Note that the
1522               --  value of the exponent must be known compile time. Otherwise,
1523               --  the exponentiation evaluation will return an error message.
1524
1525               if L_Has_Dimensions then
1526                  if not Compile_Time_Known_Value (R) then
1527                     Error_Msg_N
1528                       ("exponent of dimensioned operand must be "
1529                        & "known at compile time", N);
1530                  end if;
1531
1532                  declare
1533                     Exponent_Value : Rational := Zero;
1534
1535                  begin
1536                     --  Real operand case
1537
1538                     if Is_Real_Type (Etype (L)) then
1539
1540                        --  Define the exponent as a Rational number
1541
1542                        Exponent_Value := Create_Rational_From (R, False);
1543
1544                        --  Verify that the exponent cannot be interpreted
1545                        --  as a rational, otherwise interpret the exponent
1546                        --  as an integer.
1547
1548                        if Exponent_Value = No_Rational then
1549                           Exponent_Value :=
1550                             +Whole (UI_To_Int (Expr_Value (R)));
1551                        end if;
1552
1553                     --  Integer operand case.
1554
1555                     --  For integer operand, the exponent cannot be
1556                     --  interpreted as a rational.
1557
1558                     else
1559                        Exponent_Value := +Whole (UI_To_Int (Expr_Value (R)));
1560                     end if;
1561
1562                     for Position in Dimension_Type'Range loop
1563                        Dims_Of_N (Position) :=
1564                          Dims_Of_L (Position) * Exponent_Value;
1565                     end loop;
1566
1567                     if Exists (Dims_Of_N) then
1568                        Set_Dimensions (N, Dims_Of_N);
1569                     end if;
1570                  end;
1571               end if;
1572
1573            --  Comparison cases
1574
1575            --  For relational operations, only dimension checking is
1576            --  performed (no propagation). If one operand is the result
1577            --  of constant folding the dimensions may have been lost
1578            --  in a tree copy, so assume that preanalysis has verified
1579            --  that dimensions are correct.
1580
1581            elsif N_Kind in N_Op_Compare then
1582               if (L_Has_Dimensions or R_Has_Dimensions)
1583                 and then Dims_Of_L /= Dims_Of_R
1584               then
1585                  if Nkind (L) = N_Real_Literal
1586                    and then not (Comes_From_Source (L))
1587                    and then Expander_Active
1588                  then
1589                     null;
1590
1591                  elsif Nkind (R) = N_Real_Literal
1592                    and then not (Comes_From_Source (R))
1593                    and then Expander_Active
1594                  then
1595                     null;
1596
1597                  --  Numeric literal case. Issue a warning to indicate the
1598                  --  literal is treated as if its dimension matches the type
1599                  --  dimension.
1600
1601                  elsif Nkind_In (Original_Node (L), N_Integer_Literal,
1602                                                     N_Real_Literal)
1603                  then
1604                     Dim_Warning_For_Numeric_Literal (L, Etype (R));
1605
1606                  elsif Nkind_In (Original_Node (R), N_Integer_Literal,
1607                                                     N_Real_Literal)
1608                  then
1609                     Dim_Warning_For_Numeric_Literal (R, Etype (L));
1610
1611                  else
1612                     Error_Dim_Msg_For_Binary_Op (N, L, R);
1613                  end if;
1614               end if;
1615            end if;
1616
1617            --  If expander is active, remove dimension information from each
1618            --  operand, as only dimensions of result are relevant.
1619
1620            if Expander_Active then
1621               Remove_Dimensions (L);
1622               Remove_Dimensions (R);
1623            end if;
1624         end;
1625      end if;
1626   end Analyze_Dimension_Binary_Op;
1627
1628   ----------------------------
1629   -- Analyze_Dimension_Call --
1630   ----------------------------
1631
1632   procedure Analyze_Dimension_Call (N : Node_Id; Nam : Entity_Id) is
1633      Actuals        : constant List_Id := Parameter_Associations (N);
1634      Actual         : Node_Id;
1635      Dims_Of_Formal : Dimension_Type;
1636      Formal         : Node_Id;
1637      Formal_Typ     : Entity_Id;
1638
1639      Error_Detected : Boolean := False;
1640      --  This flag is used in order to indicate if an error has been detected
1641      --  so far by the compiler in this routine.
1642
1643   begin
1644      --  Aspect is an Ada 2012 feature. Note that there is no need to check
1645      --  dimensions for calls in inlined bodies, or calls that don't come
1646      --  from source, or those that may have semantic errors.
1647
1648      if Ada_Version < Ada_2012
1649        or else In_Inlined_Body
1650        or else not Comes_From_Source (N)
1651        or else Error_Posted (N)
1652      then
1653         return;
1654      end if;
1655
1656      --  Check the dimensions of the actuals, if any
1657
1658      if not Is_Empty_List (Actuals) then
1659
1660         --  Special processing for elementary functions
1661
1662         --  For Sqrt call, the resulting dimensions equal to half the
1663         --  dimensions of the actual. For all other elementary calls, this
1664         --  routine check that every actual is dimensionless.
1665
1666         if Nkind (N) = N_Function_Call then
1667            Elementary_Function_Calls : declare
1668               Dims_Of_Call : Dimension_Type;
1669               Ent          : Entity_Id := Nam;
1670
1671               function Is_Elementary_Function_Entity
1672                 (Sub_Id : Entity_Id) return Boolean;
1673               --  Given Sub_Id, the original subprogram entity, return True
1674               --  if call is to an elementary function (see Ada.Numerics.
1675               --  Generic_Elementary_Functions).
1676
1677               -----------------------------------
1678               -- Is_Elementary_Function_Entity --
1679               -----------------------------------
1680
1681               function Is_Elementary_Function_Entity
1682                 (Sub_Id : Entity_Id) return Boolean
1683               is
1684                  Loc : constant Source_Ptr := Sloc (Sub_Id);
1685
1686               begin
1687                  --  Is entity in Ada.Numerics.Generic_Elementary_Functions?
1688
1689                  return
1690                    Loc > No_Location
1691                      and then
1692                        Is_RTU
1693                          (Cunit_Entity (Get_Source_Unit (Loc)),
1694                            Ada_Numerics_Generic_Elementary_Functions);
1695               end Is_Elementary_Function_Entity;
1696
1697            --  Start of processing for Elementary_Function_Calls
1698
1699            begin
1700               --  Get original subprogram entity following the renaming chain
1701
1702               if Present (Alias (Ent)) then
1703                  Ent := Alias (Ent);
1704               end if;
1705
1706               --  Check the call is an Elementary function call
1707
1708               if Is_Elementary_Function_Entity (Ent) then
1709
1710                  --  Sqrt function call case
1711
1712                  if Chars (Ent) = Name_Sqrt then
1713                     Dims_Of_Call := Dimensions_Of (First_Actual (N));
1714
1715                     --  Evaluates the resulting dimensions (i.e. half the
1716                     --  dimensions of the actual).
1717
1718                     if Exists (Dims_Of_Call) then
1719                        for Position in Dims_Of_Call'Range loop
1720                           Dims_Of_Call (Position) :=
1721                             Dims_Of_Call (Position) *
1722                               Rational'(Numerator => 1, Denominator => 2);
1723                        end loop;
1724
1725                        Set_Dimensions (N, Dims_Of_Call);
1726                     end if;
1727
1728                  --  All other elementary functions case. Note that every
1729                  --  actual here should be dimensionless.
1730
1731                  else
1732                     Actual := First_Actual (N);
1733                     while Present (Actual) loop
1734                        if Exists (Dimensions_Of (Actual)) then
1735
1736                           --  Check if error has already been encountered
1737
1738                           if not Error_Detected then
1739                              Error_Msg_NE
1740                                ("dimensions mismatch in call of&",
1741                                 N, Name (N));
1742                              Error_Detected := True;
1743                           end if;
1744
1745                           Error_Msg_N
1746                             ("\expected dimension '['], found "
1747                              & Dimensions_Msg_Of (Actual), Actual);
1748                        end if;
1749
1750                        Next_Actual (Actual);
1751                     end loop;
1752                  end if;
1753
1754                  --  Nothing more to do for elementary functions
1755
1756                  return;
1757               end if;
1758            end Elementary_Function_Calls;
1759         end if;
1760
1761         --  General case. Check, for each parameter, the dimensions of the
1762         --  actual and its corresponding formal match. Otherwise, complain.
1763
1764         Actual := First_Actual (N);
1765         Formal := First_Formal (Nam);
1766         while Present (Formal) loop
1767
1768            --  A missing corresponding actual indicates that the analysis of
1769            --  the call was aborted due to a previous error.
1770
1771            if No (Actual) then
1772               Check_Error_Detected;
1773               return;
1774            end if;
1775
1776            Formal_Typ     := Etype (Formal);
1777            Dims_Of_Formal := Dimensions_Of (Formal_Typ);
1778
1779            --  If the formal is not dimensionless, check dimensions of formal
1780            --  and actual match. Otherwise, complain.
1781
1782            if Exists (Dims_Of_Formal)
1783              and then Dimensions_Of (Actual) /= Dims_Of_Formal
1784            then
1785               --  Check if an error has already been encountered so far
1786
1787               if not Error_Detected then
1788                  Error_Msg_NE ("dimensions mismatch in& call", N, Name (N));
1789                  Error_Detected := True;
1790               end if;
1791
1792               Error_Msg_N
1793                 ("\expected dimension " & Dimensions_Msg_Of (Formal_Typ)
1794                  & ", found " & Dimensions_Msg_Of (Actual), Actual);
1795            end if;
1796
1797            Next_Actual (Actual);
1798            Next_Formal (Formal);
1799         end loop;
1800      end if;
1801
1802      --  For function calls, propagate the dimensions from the returned type
1803
1804      if Nkind (N) = N_Function_Call then
1805         Analyze_Dimension_Has_Etype (N);
1806      end if;
1807   end Analyze_Dimension_Call;
1808
1809   ---------------------------------------
1810   -- Analyze_Dimension_Case_Expression --
1811   ---------------------------------------
1812
1813   procedure Analyze_Dimension_Case_Expression (N : Node_Id) is
1814      Frst      : constant Node_Id        := First (Alternatives (N));
1815      Frst_Expr : constant Node_Id        := Expression (Frst);
1816      Dims      : constant Dimension_Type := Dimensions_Of (Frst_Expr);
1817
1818      Alt : Node_Id;
1819
1820   begin
1821      Alt := Next (Frst);
1822      while Present (Alt) loop
1823         if Dimensions_Of (Expression (Alt)) /= Dims then
1824            Error_Msg_N ("dimension mismatch in case expression", Alt);
1825            exit;
1826         end if;
1827
1828         Next (Alt);
1829      end loop;
1830
1831      Copy_Dimensions (Frst_Expr, N);
1832   end Analyze_Dimension_Case_Expression;
1833
1834   ---------------------------------------------
1835   -- Analyze_Dimension_Component_Declaration --
1836   ---------------------------------------------
1837
1838   procedure Analyze_Dimension_Component_Declaration (N : Node_Id) is
1839      Expr         : constant Node_Id        := Expression (N);
1840      Id           : constant Entity_Id      := Defining_Identifier (N);
1841      Etyp         : constant Entity_Id      := Etype (Id);
1842      Dims_Of_Etyp : constant Dimension_Type := Dimensions_Of (Etyp);
1843      Dims_Of_Expr : Dimension_Type;
1844
1845      procedure Error_Dim_Msg_For_Component_Declaration
1846        (N    : Node_Id;
1847         Etyp : Entity_Id;
1848         Expr : Node_Id);
1849      --  Error using Error_Msg_N at node N. Output the dimensions of the
1850      --  type Etyp and the expression Expr of N.
1851
1852      ---------------------------------------------
1853      -- Error_Dim_Msg_For_Component_Declaration --
1854      ---------------------------------------------
1855
1856      procedure Error_Dim_Msg_For_Component_Declaration
1857        (N    : Node_Id;
1858         Etyp : Entity_Id;
1859         Expr : Node_Id) is
1860      begin
1861         Error_Msg_N ("dimensions mismatch in component declaration", N);
1862         Error_Msg_N
1863           ("\expected dimension " & Dimensions_Msg_Of (Etyp) & ", found "
1864            & Dimensions_Msg_Of (Expr), Expr);
1865      end Error_Dim_Msg_For_Component_Declaration;
1866
1867   --  Start of processing for Analyze_Dimension_Component_Declaration
1868
1869   begin
1870      --  Expression is present
1871
1872      if Present (Expr) then
1873         Dims_Of_Expr := Dimensions_Of (Expr);
1874
1875         --  Check dimensions match
1876
1877         if Dims_Of_Etyp /= Dims_Of_Expr then
1878
1879            --  Numeric literal case. Issue a warning if the object type is not
1880            --  dimensionless to indicate the literal is treated as if its
1881            --  dimension matches the type dimension.
1882
1883            if Nkind_In (Original_Node (Expr), N_Real_Literal,
1884                                               N_Integer_Literal)
1885            then
1886               Dim_Warning_For_Numeric_Literal (Expr, Etyp);
1887
1888            --  Issue a dimension mismatch error for all other cases
1889
1890            else
1891               Error_Dim_Msg_For_Component_Declaration (N, Etyp, Expr);
1892            end if;
1893         end if;
1894      end if;
1895   end Analyze_Dimension_Component_Declaration;
1896
1897   -------------------------------------------------
1898   -- Analyze_Dimension_Extended_Return_Statement --
1899   -------------------------------------------------
1900
1901   procedure Analyze_Dimension_Extended_Return_Statement (N : Node_Id) is
1902      Return_Ent       : constant Entity_Id := Return_Statement_Entity (N);
1903      Return_Etyp      : constant Entity_Id :=
1904                           Etype (Return_Applies_To (Return_Ent));
1905      Return_Obj_Decls : constant List_Id := Return_Object_Declarations (N);
1906      Return_Obj_Decl  : Node_Id;
1907      Return_Obj_Id    : Entity_Id;
1908      Return_Obj_Typ   : Entity_Id;
1909
1910      procedure Error_Dim_Msg_For_Extended_Return_Statement
1911        (N              : Node_Id;
1912         Return_Etyp    : Entity_Id;
1913         Return_Obj_Typ : Entity_Id);
1914      --  Error using Error_Msg_N at node N. Output dimensions of the returned
1915      --  type Return_Etyp and the returned object type Return_Obj_Typ of N.
1916
1917      -------------------------------------------------
1918      -- Error_Dim_Msg_For_Extended_Return_Statement --
1919      -------------------------------------------------
1920
1921      procedure Error_Dim_Msg_For_Extended_Return_Statement
1922        (N              : Node_Id;
1923         Return_Etyp    : Entity_Id;
1924         Return_Obj_Typ : Entity_Id)
1925      is
1926      begin
1927         Error_Msg_N ("dimensions mismatch in extended return statement", N);
1928         Error_Msg_N
1929           ("\expected dimension " & Dimensions_Msg_Of (Return_Etyp)
1930            & ", found " & Dimensions_Msg_Of (Return_Obj_Typ), N);
1931      end Error_Dim_Msg_For_Extended_Return_Statement;
1932
1933   --  Start of processing for Analyze_Dimension_Extended_Return_Statement
1934
1935   begin
1936      if Present (Return_Obj_Decls) then
1937         Return_Obj_Decl := First (Return_Obj_Decls);
1938         while Present (Return_Obj_Decl) loop
1939            if Nkind (Return_Obj_Decl) = N_Object_Declaration then
1940               Return_Obj_Id := Defining_Identifier (Return_Obj_Decl);
1941
1942               if Is_Return_Object (Return_Obj_Id) then
1943                  Return_Obj_Typ := Etype (Return_Obj_Id);
1944
1945                  --  Issue an error message if dimensions mismatch
1946
1947                  if Dimensions_Of (Return_Etyp) /=
1948                       Dimensions_Of (Return_Obj_Typ)
1949                  then
1950                     Error_Dim_Msg_For_Extended_Return_Statement
1951                       (N, Return_Etyp, Return_Obj_Typ);
1952                     return;
1953                  end if;
1954               end if;
1955            end if;
1956
1957            Next (Return_Obj_Decl);
1958         end loop;
1959      end if;
1960   end Analyze_Dimension_Extended_Return_Statement;
1961
1962   -----------------------------------------------------
1963   -- Analyze_Dimension_Extension_Or_Record_Aggregate --
1964   -----------------------------------------------------
1965
1966   procedure Analyze_Dimension_Extension_Or_Record_Aggregate (N : Node_Id) is
1967      Comp     : Node_Id;
1968      Comp_Id  : Entity_Id;
1969      Comp_Typ : Entity_Id;
1970      Expr     : Node_Id;
1971
1972      Error_Detected : Boolean := False;
1973      --  This flag is used in order to indicate if an error has been detected
1974      --  so far by the compiler in this routine.
1975
1976   begin
1977      --  Aspect is an Ada 2012 feature. Note that there is no need to check
1978      --  dimensions in inlined bodies, or for aggregates that don't come
1979      --  from source, or if we are within an initialization procedure, whose
1980      --  expressions have been checked at the point of record declaration.
1981
1982      if Ada_Version < Ada_2012
1983        or else In_Inlined_Body
1984        or else not Comes_From_Source (N)
1985        or else Inside_Init_Proc
1986      then
1987         return;
1988      end if;
1989
1990      Comp := First (Component_Associations (N));
1991      while Present (Comp) loop
1992         Comp_Id  := Entity (First (Choices (Comp)));
1993         Comp_Typ := Etype (Comp_Id);
1994
1995         --  Check the component type is either a dimensioned type or a
1996         --  dimensioned subtype.
1997
1998         if Has_Dimension_System (Base_Type (Comp_Typ)) then
1999            Expr := Expression (Comp);
2000
2001            --  A box-initialized component needs no checking.
2002
2003            if No (Expr) and then Box_Present (Comp) then
2004               null;
2005
2006            --  Issue an error if the dimensions of the component type and the
2007            --  dimensions of the component mismatch.
2008
2009            elsif Dimensions_Of (Expr) /= Dimensions_Of (Comp_Typ) then
2010
2011               --  Check if an error has already been encountered so far
2012
2013               if not Error_Detected then
2014
2015                  --  Extension aggregate case
2016
2017                  if Nkind (N) = N_Extension_Aggregate then
2018                     Error_Msg_N
2019                       ("dimensions mismatch in extension aggregate", N);
2020
2021                  --  Record aggregate case
2022
2023                  else
2024                     Error_Msg_N
2025                       ("dimensions mismatch in record aggregate", N);
2026                  end if;
2027
2028                  Error_Detected := True;
2029               end if;
2030
2031               Error_Msg_N
2032                 ("\expected dimension " & Dimensions_Msg_Of (Comp_Typ)
2033                  & ", found " & Dimensions_Msg_Of (Expr), Comp);
2034            end if;
2035         end if;
2036
2037         Next (Comp);
2038      end loop;
2039   end Analyze_Dimension_Extension_Or_Record_Aggregate;
2040
2041   -------------------------------
2042   -- Analyze_Dimension_Formals --
2043   -------------------------------
2044
2045   procedure Analyze_Dimension_Formals (N : Node_Id; Formals : List_Id) is
2046      Dims_Of_Typ : Dimension_Type;
2047      Formal      : Node_Id;
2048      Typ         : Entity_Id;
2049
2050   begin
2051      --  Aspect is an Ada 2012 feature. Note that there is no need to check
2052      --  dimensions for sub specs that don't come from source.
2053
2054      if Ada_Version < Ada_2012 or else not Comes_From_Source (N) then
2055         return;
2056      end if;
2057
2058      Formal := First (Formals);
2059      while Present (Formal) loop
2060         Typ         := Parameter_Type (Formal);
2061         Dims_Of_Typ := Dimensions_Of  (Typ);
2062
2063         if Exists (Dims_Of_Typ) then
2064            declare
2065               Expr : constant Node_Id := Expression (Formal);
2066
2067            begin
2068               --  Issue a warning if Expr is a numeric literal and if its
2069               --  dimensions differ with the dimensions of the formal type.
2070
2071               if Present (Expr)
2072                 and then Dims_Of_Typ /= Dimensions_Of (Expr)
2073                 and then Nkind_In (Original_Node (Expr), N_Real_Literal,
2074                                                          N_Integer_Literal)
2075               then
2076                  Dim_Warning_For_Numeric_Literal (Expr, Etype (Typ));
2077               end if;
2078            end;
2079         end if;
2080
2081         Next (Formal);
2082      end loop;
2083   end Analyze_Dimension_Formals;
2084
2085   ---------------------------------
2086   -- Analyze_Dimension_Has_Etype --
2087   ---------------------------------
2088
2089   procedure Analyze_Dimension_Has_Etype (N : Node_Id) is
2090      Etyp         : constant Entity_Id := Etype (N);
2091      Dims_Of_Etyp : Dimension_Type     := Dimensions_Of (Etyp);
2092
2093   begin
2094      --  General case. Propagation of the dimensions from the type
2095
2096      if Exists (Dims_Of_Etyp) then
2097         Set_Dimensions (N, Dims_Of_Etyp);
2098
2099      --  Identifier case. Propagate the dimensions from the entity for
2100      --  identifier whose entity is a non-dimensionless constant.
2101
2102      elsif Nkind (N) = N_Identifier then
2103         Analyze_Dimension_Identifier : declare
2104            Id : constant Entity_Id := Entity (N);
2105
2106         begin
2107            --  If Id is missing, abnormal tree, assume previous error
2108
2109            if No (Id) then
2110               Check_Error_Detected;
2111               return;
2112
2113            elsif Ekind_In (Id,  E_Constant, E_Named_Real)
2114              and then Exists (Dimensions_Of (Id))
2115            then
2116               Set_Dimensions (N, Dimensions_Of (Id));
2117            end if;
2118         end Analyze_Dimension_Identifier;
2119
2120      --  Attribute reference case. Propagate the dimensions from the prefix.
2121
2122      elsif Nkind (N) = N_Attribute_Reference
2123        and then Has_Dimension_System (Base_Type (Etyp))
2124      then
2125         Dims_Of_Etyp := Dimensions_Of (Prefix (N));
2126
2127         --  Check the prefix is not dimensionless
2128
2129         if Exists (Dims_Of_Etyp) then
2130            Set_Dimensions (N, Dims_Of_Etyp);
2131         end if;
2132      end if;
2133
2134      --  Remove dimensions from inner expressions, to prevent dimensions
2135      --  table from growing uselessly.
2136
2137      case Nkind (N) is
2138         when N_Attribute_Reference
2139            | N_Indexed_Component
2140         =>
2141            declare
2142               Exprs : constant List_Id := Expressions (N);
2143               Expr  : Node_Id;
2144
2145            begin
2146               if Present (Exprs) then
2147                  Expr := First (Exprs);
2148                  while Present (Expr) loop
2149                     Remove_Dimensions (Expr);
2150                     Next (Expr);
2151                  end loop;
2152               end if;
2153            end;
2154
2155         when N_Qualified_Expression
2156            | N_Type_Conversion
2157            | N_Unchecked_Type_Conversion
2158         =>
2159            Remove_Dimensions (Expression (N));
2160
2161         when N_Selected_Component =>
2162            Remove_Dimensions (Selector_Name (N));
2163
2164         when others =>
2165            null;
2166      end case;
2167   end Analyze_Dimension_Has_Etype;
2168
2169   -------------------------------------
2170   -- Analyze_Dimension_If_Expression --
2171   -------------------------------------
2172
2173   procedure Analyze_Dimension_If_Expression (N : Node_Id) is
2174      Then_Expr : constant Node_Id := Next (First (Expressions (N)));
2175      Else_Expr : constant Node_Id := Next (Then_Expr);
2176
2177   begin
2178      if Dimensions_Of (Then_Expr) /= Dimensions_Of (Else_Expr) then
2179         Error_Msg_N ("dimensions mismatch in conditional expression", N);
2180      else
2181         Copy_Dimensions (Then_Expr, N);
2182      end if;
2183   end Analyze_Dimension_If_Expression;
2184
2185   ------------------------------------------
2186   -- Analyze_Dimension_Number_Declaration --
2187   ------------------------------------------
2188
2189   procedure Analyze_Dimension_Number_Declaration (N : Node_Id) is
2190      Expr        : constant Node_Id        := Expression (N);
2191      Id          : constant Entity_Id      := Defining_Identifier (N);
2192      Dim_Of_Expr : constant Dimension_Type := Dimensions_Of (Expr);
2193
2194   begin
2195      if Exists (Dim_Of_Expr) then
2196         Set_Dimensions (Id, Dim_Of_Expr);
2197         Set_Etype (Id, Etype (Expr));
2198      end if;
2199   end Analyze_Dimension_Number_Declaration;
2200
2201   ------------------------------------------
2202   -- Analyze_Dimension_Object_Declaration --
2203   ------------------------------------------
2204
2205   procedure Analyze_Dimension_Object_Declaration (N : Node_Id) is
2206      Expr        : constant Node_Id   := Expression (N);
2207      Id          : constant Entity_Id := Defining_Identifier (N);
2208      Etyp        : constant Entity_Id := Etype (Id);
2209      Dim_Of_Etyp : constant Dimension_Type := Dimensions_Of (Etyp);
2210      Dim_Of_Expr : Dimension_Type;
2211
2212      procedure Error_Dim_Msg_For_Object_Declaration
2213        (N    : Node_Id;
2214         Etyp : Entity_Id;
2215         Expr : Node_Id);
2216      --  Error using Error_Msg_N at node N. Output the dimensions of the
2217      --  type Etyp and of the expression Expr.
2218
2219      ------------------------------------------
2220      -- Error_Dim_Msg_For_Object_Declaration --
2221      ------------------------------------------
2222
2223      procedure Error_Dim_Msg_For_Object_Declaration
2224        (N    : Node_Id;
2225         Etyp : Entity_Id;
2226         Expr : Node_Id) is
2227      begin
2228         Error_Msg_N ("dimensions mismatch in object declaration", N);
2229         Error_Msg_N
2230           ("\expected dimension " & Dimensions_Msg_Of (Etyp) & ", found "
2231            & Dimensions_Msg_Of (Expr), Expr);
2232      end Error_Dim_Msg_For_Object_Declaration;
2233
2234   --  Start of processing for Analyze_Dimension_Object_Declaration
2235
2236   begin
2237      --  Expression is present
2238
2239      if Present (Expr) then
2240         Dim_Of_Expr := Dimensions_Of (Expr);
2241
2242         --  Check dimensions match
2243
2244         if Dim_Of_Expr /= Dim_Of_Etyp then
2245
2246            --  Numeric literal case. Issue a warning if the object type is
2247            --  not dimensionless to indicate the literal is treated as if
2248            --  its dimension matches the type dimension.
2249
2250            if Nkind_In (Original_Node (Expr), N_Real_Literal,
2251                                               N_Integer_Literal)
2252            then
2253               Dim_Warning_For_Numeric_Literal (Expr, Etyp);
2254
2255            --  Case of object is a constant whose type is a dimensioned type
2256
2257            elsif Constant_Present (N) and then not Exists (Dim_Of_Etyp) then
2258
2259               --  Propagate dimension from expression to object entity
2260
2261               Set_Dimensions (Id, Dim_Of_Expr);
2262
2263            --  Expression may have been constant-folded. If nominal type has
2264            --  dimensions, verify that expression has same type.
2265
2266            elsif Exists (Dim_Of_Etyp) and then Etype (Expr) = Etyp then
2267               null;
2268
2269            --  For all other cases, issue an error message
2270
2271            else
2272               Error_Dim_Msg_For_Object_Declaration (N, Etyp, Expr);
2273            end if;
2274         end if;
2275
2276         --  Remove dimensions in expression after checking consistency with
2277         --  given type.
2278
2279         Remove_Dimensions (Expr);
2280      end if;
2281   end Analyze_Dimension_Object_Declaration;
2282
2283   ---------------------------------------------------
2284   -- Analyze_Dimension_Object_Renaming_Declaration --
2285   ---------------------------------------------------
2286
2287   procedure Analyze_Dimension_Object_Renaming_Declaration (N : Node_Id) is
2288      Renamed_Name : constant Node_Id := Name (N);
2289      Sub_Mark     : constant Node_Id := Subtype_Mark (N);
2290
2291      procedure Error_Dim_Msg_For_Object_Renaming_Declaration
2292        (N            : Node_Id;
2293         Sub_Mark     : Node_Id;
2294         Renamed_Name : Node_Id);
2295      --  Error using Error_Msg_N at node N. Output the dimensions of
2296      --  Sub_Mark and of Renamed_Name.
2297
2298      ---------------------------------------------------
2299      -- Error_Dim_Msg_For_Object_Renaming_Declaration --
2300      ---------------------------------------------------
2301
2302      procedure Error_Dim_Msg_For_Object_Renaming_Declaration
2303        (N            : Node_Id;
2304         Sub_Mark     : Node_Id;
2305         Renamed_Name : Node_Id) is
2306      begin
2307         Error_Msg_N ("dimensions mismatch in object renaming declaration", N);
2308         Error_Msg_N
2309           ("\expected dimension " & Dimensions_Msg_Of (Sub_Mark) & ", found "
2310            & Dimensions_Msg_Of (Renamed_Name), Renamed_Name);
2311      end Error_Dim_Msg_For_Object_Renaming_Declaration;
2312
2313   --  Start of processing for Analyze_Dimension_Object_Renaming_Declaration
2314
2315   begin
2316      if Dimensions_Of (Renamed_Name) /= Dimensions_Of (Sub_Mark) then
2317         Error_Dim_Msg_For_Object_Renaming_Declaration
2318           (N, Sub_Mark, Renamed_Name);
2319      end if;
2320   end Analyze_Dimension_Object_Renaming_Declaration;
2321
2322   -----------------------------------------------
2323   -- Analyze_Dimension_Simple_Return_Statement --
2324   -----------------------------------------------
2325
2326   procedure Analyze_Dimension_Simple_Return_Statement (N : Node_Id) is
2327      Expr                : constant Node_Id := Expression (N);
2328      Return_Ent          : constant Entity_Id := Return_Statement_Entity (N);
2329      Return_Etyp         : constant Entity_Id :=
2330                              Etype (Return_Applies_To (Return_Ent));
2331      Dims_Of_Return_Etyp : constant Dimension_Type :=
2332                              Dimensions_Of (Return_Etyp);
2333
2334      procedure Error_Dim_Msg_For_Simple_Return_Statement
2335        (N           : Node_Id;
2336         Return_Etyp : Entity_Id;
2337         Expr        : Node_Id);
2338      --  Error using Error_Msg_N at node N. Output the dimensions of the
2339      --  returned type Return_Etyp and the returned expression Expr of N.
2340
2341      -----------------------------------------------
2342      -- Error_Dim_Msg_For_Simple_Return_Statement --
2343      -----------------------------------------------
2344
2345      procedure Error_Dim_Msg_For_Simple_Return_Statement
2346        (N           : Node_Id;
2347         Return_Etyp : Entity_Id;
2348         Expr        : Node_Id)
2349      is
2350      begin
2351         Error_Msg_N ("dimensions mismatch in return statement", N);
2352         Error_Msg_N
2353           ("\expected dimension " & Dimensions_Msg_Of (Return_Etyp)
2354            & ", found " & Dimensions_Msg_Of (Expr), Expr);
2355      end Error_Dim_Msg_For_Simple_Return_Statement;
2356
2357   --  Start of processing for Analyze_Dimension_Simple_Return_Statement
2358
2359   begin
2360      if Dims_Of_Return_Etyp /= Dimensions_Of (Expr) then
2361         Error_Dim_Msg_For_Simple_Return_Statement (N, Return_Etyp, Expr);
2362         Remove_Dimensions (Expr);
2363      end if;
2364   end Analyze_Dimension_Simple_Return_Statement;
2365
2366   -------------------------------------------
2367   -- Analyze_Dimension_Subtype_Declaration --
2368   -------------------------------------------
2369
2370   procedure Analyze_Dimension_Subtype_Declaration (N : Node_Id) is
2371      Id           : constant Entity_Id := Defining_Identifier (N);
2372      Dims_Of_Id   : constant Dimension_Type := Dimensions_Of (Id);
2373      Dims_Of_Etyp : Dimension_Type;
2374      Etyp         : Node_Id;
2375
2376   begin
2377      --  No constraint case in subtype declaration
2378
2379      if Nkind (Subtype_Indication (N)) /= N_Subtype_Indication then
2380         Etyp := Etype (Subtype_Indication (N));
2381         Dims_Of_Etyp := Dimensions_Of (Etyp);
2382
2383         if Exists (Dims_Of_Etyp) then
2384
2385            --  If subtype already has a dimension (from Aspect_Dimension), it
2386            --  cannot inherit different dimensions from its subtype.
2387
2388            if Exists (Dims_Of_Id) and then Dims_Of_Etyp /= Dims_Of_Id then
2389               Error_Msg_NE
2390                 ("subtype& already " & Dimensions_Msg_Of (Id, True), N, Id);
2391            else
2392               Set_Dimensions (Id, Dims_Of_Etyp);
2393               Set_Symbol (Id, Symbol_Of (Etyp));
2394            end if;
2395         end if;
2396
2397      --  Constraint present in subtype declaration
2398
2399      else
2400         Etyp := Etype (Subtype_Mark (Subtype_Indication (N)));
2401         Dims_Of_Etyp := Dimensions_Of (Etyp);
2402
2403         if Exists (Dims_Of_Etyp) then
2404            Set_Dimensions (Id, Dims_Of_Etyp);
2405            Set_Symbol (Id, Symbol_Of (Etyp));
2406         end if;
2407      end if;
2408   end Analyze_Dimension_Subtype_Declaration;
2409
2410   ---------------------------------------
2411   -- Analyze_Dimension_Type_Conversion --
2412   ---------------------------------------
2413
2414   procedure Analyze_Dimension_Type_Conversion (N : Node_Id) is
2415      Expr_Root   : constant Entity_Id :=
2416                      Dimension_System_Root (Etype (Expression (N)));
2417      Target_Root : constant Entity_Id :=
2418                      Dimension_System_Root (Etype (N));
2419
2420   begin
2421      --  If the expression has dimensions and the target type has dimensions,
2422      --  the conversion has the dimensions of the expression. Consistency is
2423      --  checked below. Converting to a non-dimensioned type such as Float
2424      --  ignores the dimensions of the expression.
2425
2426      if Exists (Dimensions_Of (Expression (N)))
2427        and then Present (Target_Root)
2428      then
2429         Set_Dimensions (N, Dimensions_Of (Expression (N)));
2430
2431      --  Otherwise the dimensions are those of the target type.
2432
2433      else
2434         Analyze_Dimension_Has_Etype (N);
2435      end if;
2436
2437      --  A conversion between types in different dimension systems (e.g. MKS
2438      --  and British units) must respect the dimensions of expression and
2439      --  type, It is up to the user to provide proper conversion factors.
2440
2441      --  Upward conversions to root type of a dimensioned system are legal,
2442      --  and correspond to "view conversions", i.e. preserve the dimensions
2443      --  of the expression; otherwise conversion must be between types with
2444      --  then same dimensions. Conversions to a non-dimensioned type such as
2445      --  Float lose the dimensions of the expression.
2446
2447      if Present (Expr_Root)
2448       and then Present (Target_Root)
2449       and then Etype (N) /= Target_Root
2450       and then Dimensions_Of (Expression (N)) /= Dimensions_Of (Etype (N))
2451      then
2452         Error_Msg_N ("dimensions mismatch in conversion", N);
2453         Error_Msg_N
2454           ("\expression " & Dimensions_Msg_Of (Expression (N), True), N);
2455         Error_Msg_N
2456           ("\target type " & Dimensions_Msg_Of (Etype (N), True), N);
2457      end if;
2458   end Analyze_Dimension_Type_Conversion;
2459
2460   --------------------------------
2461   -- Analyze_Dimension_Unary_Op --
2462   --------------------------------
2463
2464   procedure Analyze_Dimension_Unary_Op (N : Node_Id) is
2465   begin
2466      case Nkind (N) is
2467
2468         --  Propagate the dimension if the operand is not dimensionless
2469
2470         when N_Op_Abs
2471            | N_Op_Minus
2472            | N_Op_Plus
2473         =>
2474            declare
2475               R : constant Node_Id := Right_Opnd (N);
2476            begin
2477               Move_Dimensions (R, N);
2478            end;
2479
2480         when others =>
2481            null;
2482      end case;
2483   end Analyze_Dimension_Unary_Op;
2484
2485   ---------------------------------
2486   -- Check_Expression_Dimensions --
2487   ---------------------------------
2488
2489   procedure Check_Expression_Dimensions
2490     (Expr : Node_Id;
2491      Typ  : Entity_Id)
2492   is
2493   begin
2494      if Is_Floating_Point_Type (Etype (Expr)) then
2495         Analyze_Dimension (Expr);
2496
2497         if Dimensions_Of (Expr) /= Dimensions_Of (Typ) then
2498            Error_Msg_N ("dimensions mismatch in array aggregate", Expr);
2499            Error_Msg_N
2500              ("\expected dimension " & Dimensions_Msg_Of (Typ)
2501               & ", found " & Dimensions_Msg_Of (Expr), Expr);
2502         end if;
2503      end if;
2504   end Check_Expression_Dimensions;
2505
2506   ---------------------
2507   -- Copy_Dimensions --
2508   ---------------------
2509
2510   procedure Copy_Dimensions (From : Node_Id; To : Node_Id) is
2511      Dims_Of_From : constant Dimension_Type := Dimensions_Of (From);
2512
2513   begin
2514      --  Ignore if not Ada 2012 or beyond
2515
2516      if Ada_Version < Ada_2012 then
2517         return;
2518
2519      --  For Ada 2012, Copy the dimension of 'From to 'To'
2520
2521      elsif Exists (Dims_Of_From) then
2522         Set_Dimensions (To, Dims_Of_From);
2523      end if;
2524   end Copy_Dimensions;
2525
2526   -----------------------------------
2527   -- Copy_Dimensions_Of_Components --
2528   -----------------------------------
2529
2530   procedure Copy_Dimensions_Of_Components (Rec : Entity_Id) is
2531      C : Entity_Id;
2532
2533   begin
2534      C := First_Component (Rec);
2535      while Present (C) loop
2536         if Nkind (Parent (C)) = N_Component_Declaration then
2537            Copy_Dimensions
2538              (Expression (Parent (Corresponding_Record_Component (C))),
2539               Expression (Parent (C)));
2540         end if;
2541         Next_Component (C);
2542      end loop;
2543   end Copy_Dimensions_Of_Components;
2544
2545   --------------------------
2546   -- Create_Rational_From --
2547   --------------------------
2548
2549   --  RATIONAL ::= [-] NUMERAL [/ NUMERAL]
2550
2551   --  A rational number is a number that can be expressed as the quotient or
2552   --  fraction a/b of two integers, where b is non-zero positive.
2553
2554   function Create_Rational_From
2555     (Expr     : Node_Id;
2556      Complain : Boolean) return Rational
2557   is
2558      Or_Node_Of_Expr : constant Node_Id := Original_Node (Expr);
2559      Result          : Rational := No_Rational;
2560
2561      function Process_Minus (N : Node_Id) return Rational;
2562      --  Create a rational from a N_Op_Minus node
2563
2564      function Process_Divide (N : Node_Id) return Rational;
2565      --  Create a rational from a N_Op_Divide node
2566
2567      function Process_Literal (N : Node_Id) return Rational;
2568      --  Create a rational from a N_Integer_Literal node
2569
2570      -------------------
2571      -- Process_Minus --
2572      -------------------
2573
2574      function Process_Minus (N : Node_Id) return Rational is
2575         Right  : constant Node_Id := Original_Node (Right_Opnd (N));
2576         Result : Rational;
2577
2578      begin
2579         --  Operand is an integer literal
2580
2581         if Nkind (Right) = N_Integer_Literal then
2582            Result := -Process_Literal (Right);
2583
2584         --  Operand is a divide operator
2585
2586         elsif Nkind (Right) = N_Op_Divide then
2587            Result := -Process_Divide (Right);
2588
2589         else
2590            Result := No_Rational;
2591         end if;
2592
2593         --  Provide minimal semantic information on dimension expressions,
2594         --  even though they have no run-time existence. This is for use by
2595         --  ASIS tools, in particular pretty-printing. If generating code
2596         --  standard operator resolution will take place.
2597
2598         if ASIS_Mode then
2599            Set_Entity (N, Standard_Op_Minus);
2600            Set_Etype  (N, Standard_Integer);
2601         end if;
2602
2603         return Result;
2604      end Process_Minus;
2605
2606      --------------------
2607      -- Process_Divide --
2608      --------------------
2609
2610      function Process_Divide (N : Node_Id) return Rational is
2611         Left      : constant Node_Id := Original_Node (Left_Opnd (N));
2612         Right     : constant Node_Id := Original_Node (Right_Opnd (N));
2613         Left_Rat  : Rational;
2614         Result    : Rational := No_Rational;
2615         Right_Rat : Rational;
2616
2617      begin
2618         --  Both left and right operands are integer literals
2619
2620         if Nkind (Left) = N_Integer_Literal
2621              and then
2622            Nkind (Right) = N_Integer_Literal
2623         then
2624            Left_Rat := Process_Literal (Left);
2625            Right_Rat := Process_Literal (Right);
2626            Result := Left_Rat / Right_Rat;
2627         end if;
2628
2629         --  Provide minimal semantic information on dimension expressions,
2630         --  even though they have no run-time existence. This is for use by
2631         --  ASIS tools, in particular pretty-printing. If generating code
2632         --  standard operator resolution will take place.
2633
2634         if ASIS_Mode then
2635            Set_Entity (N, Standard_Op_Divide);
2636            Set_Etype  (N, Standard_Integer);
2637         end if;
2638
2639         return Result;
2640      end Process_Divide;
2641
2642      ---------------------
2643      -- Process_Literal --
2644      ---------------------
2645
2646      function Process_Literal (N : Node_Id) return Rational is
2647      begin
2648         return +Whole (UI_To_Int (Intval (N)));
2649      end Process_Literal;
2650
2651   --  Start of processing for Create_Rational_From
2652
2653   begin
2654      --  Check the expression is either a division of two integers or an
2655      --  integer itself. Note that the check applies to the original node
2656      --  since the node could have already been rewritten.
2657
2658      --  Integer literal case
2659
2660      if Nkind (Or_Node_Of_Expr) = N_Integer_Literal then
2661         Result := Process_Literal (Or_Node_Of_Expr);
2662
2663      --  Divide operator case
2664
2665      elsif Nkind (Or_Node_Of_Expr) = N_Op_Divide then
2666         Result := Process_Divide (Or_Node_Of_Expr);
2667
2668      --  Minus operator case
2669
2670      elsif Nkind (Or_Node_Of_Expr) = N_Op_Minus then
2671         Result := Process_Minus (Or_Node_Of_Expr);
2672      end if;
2673
2674      --  When Expr cannot be interpreted as a rational and Complain is true,
2675      --  generate an error message.
2676
2677      if Complain and then Result = No_Rational then
2678         Error_Msg_N ("rational expected", Expr);
2679      end if;
2680
2681      return Result;
2682   end Create_Rational_From;
2683
2684   -------------------
2685   -- Dimensions_Of --
2686   -------------------
2687
2688   function Dimensions_Of (N : Node_Id) return Dimension_Type is
2689   begin
2690      return Dimension_Table.Get (N);
2691   end Dimensions_Of;
2692
2693   -----------------------
2694   -- Dimensions_Msg_Of --
2695   -----------------------
2696
2697   function Dimensions_Msg_Of
2698      (N                  : Node_Id;
2699       Description_Needed : Boolean := False) return String
2700   is
2701      Dims_Of_N      : constant Dimension_Type := Dimensions_Of (N);
2702      Dimensions_Msg : Name_Id;
2703      System         : System_Type;
2704
2705   begin
2706      --  Initialization of Name_Buffer
2707
2708      Name_Len := 0;
2709
2710      --  N is not dimensionless
2711
2712      if Exists (Dims_Of_N) then
2713         System := System_Of (Base_Type (Etype (N)));
2714
2715         --  When Description_Needed, add to string "has dimension " before the
2716         --  actual dimension.
2717
2718         if Description_Needed then
2719            Add_Str_To_Name_Buffer ("has dimension ");
2720         end if;
2721
2722         Append
2723           (Global_Name_Buffer,
2724            From_Dim_To_Str_Of_Dim_Symbols (Dims_Of_N, System, True));
2725
2726      --  N is dimensionless
2727
2728      --  When Description_Needed, return "is dimensionless"
2729
2730      elsif Description_Needed then
2731         Add_Str_To_Name_Buffer ("is dimensionless");
2732
2733      --  Otherwise, return "'[']"
2734
2735      else
2736         Add_Str_To_Name_Buffer ("'[']");
2737      end if;
2738
2739      Dimensions_Msg := Name_Find;
2740      return Get_Name_String (Dimensions_Msg);
2741   end Dimensions_Msg_Of;
2742
2743   --------------------------
2744   -- Dimension_Table_Hash --
2745   --------------------------
2746
2747   function Dimension_Table_Hash
2748     (Key : Node_Id) return Dimension_Table_Range
2749   is
2750   begin
2751      return Dimension_Table_Range (Key mod 511);
2752   end Dimension_Table_Hash;
2753
2754   -------------------------------------
2755   -- Dim_Warning_For_Numeric_Literal --
2756   -------------------------------------
2757
2758   procedure Dim_Warning_For_Numeric_Literal (N : Node_Id; Typ : Entity_Id) is
2759   begin
2760      --  Consider the literal zero (integer 0 or real 0.0) to be of any
2761      --  dimension.
2762
2763      case Nkind (Original_Node (N)) is
2764         when N_Real_Literal =>
2765            if Expr_Value_R (N) = Ureal_0 then
2766               return;
2767            end if;
2768
2769         when N_Integer_Literal =>
2770            if Expr_Value (N) = Uint_0 then
2771               return;
2772            end if;
2773
2774         when others =>
2775            null;
2776      end case;
2777
2778      --  Initialize name buffer
2779
2780      Name_Len := 0;
2781
2782      Append (Global_Name_Buffer, String_From_Numeric_Literal (N));
2783
2784      --  Insert a blank between the literal and the symbol
2785
2786      Add_Str_To_Name_Buffer (" ");
2787      Append (Global_Name_Buffer, Symbol_Of (Typ));
2788
2789      Error_Msg_Name_1 := Name_Find;
2790      Error_Msg_N ("assumed to be%%??", N);
2791   end Dim_Warning_For_Numeric_Literal;
2792
2793   ----------------------
2794   -- Dimensions_Match --
2795   ----------------------
2796
2797   function Dimensions_Match (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2798   begin
2799      return
2800        not Has_Dimension_System (Base_Type (T1))
2801          or else Dimensions_Of (T1) = Dimensions_Of (T2);
2802   end Dimensions_Match;
2803
2804   ---------------------------
2805   -- Dimension_System_Root --
2806   ---------------------------
2807
2808   function Dimension_System_Root (T : Entity_Id) return Entity_Id is
2809      Root : Entity_Id;
2810
2811   begin
2812      Root := Base_Type (T);
2813
2814      if Has_Dimension_System (Root) then
2815         return First_Subtype (Root);   --  for example Dim_Mks
2816
2817      else
2818         return Empty;
2819      end if;
2820   end Dimension_System_Root;
2821
2822   ----------------------------------------
2823   -- Eval_Op_Expon_For_Dimensioned_Type --
2824   ----------------------------------------
2825
2826   --  Evaluate the expon operator for real dimensioned type.
2827
2828   --  Note that if the exponent is an integer (denominator = 1) the node is
2829   --  evaluated by the regular Eval_Op_Expon routine (see Sem_Eval).
2830
2831   procedure Eval_Op_Expon_For_Dimensioned_Type
2832     (N    : Node_Id;
2833      Btyp : Entity_Id)
2834   is
2835      R       : constant Node_Id := Right_Opnd (N);
2836      R_Value : Rational := No_Rational;
2837
2838   begin
2839      if Is_Real_Type (Btyp) then
2840         R_Value := Create_Rational_From (R, False);
2841      end if;
2842
2843      --  Check that the exponent is not an integer
2844
2845      if R_Value /= No_Rational and then R_Value.Denominator /= 1 then
2846         Eval_Op_Expon_With_Rational_Exponent (N, R_Value);
2847      else
2848         Eval_Op_Expon (N);
2849      end if;
2850   end Eval_Op_Expon_For_Dimensioned_Type;
2851
2852   ------------------------------------------
2853   -- Eval_Op_Expon_With_Rational_Exponent --
2854   ------------------------------------------
2855
2856   --  For dimensioned operand in exponentiation, exponent is allowed to be a
2857   --  Rational and not only an Integer like for dimensionless operands. For
2858   --  that particular case, the left operand is rewritten as a function call
2859   --  using the function Expon_LLF from s-llflex.ads.
2860
2861   procedure Eval_Op_Expon_With_Rational_Exponent
2862     (N              : Node_Id;
2863      Exponent_Value : Rational)
2864   is
2865      Loc                   : constant Source_Ptr     := Sloc (N);
2866      Dims_Of_N             : constant Dimension_Type := Dimensions_Of (N);
2867      L                     : constant Node_Id        := Left_Opnd (N);
2868      Etyp_Of_L             : constant Entity_Id      := Etype (L);
2869      Btyp_Of_L             : constant Entity_Id      := Base_Type (Etyp_Of_L);
2870      Actual_1              : Node_Id;
2871      Actual_2              : Node_Id;
2872      Dim_Power             : Rational;
2873      List_Of_Dims          : List_Id;
2874      New_Aspect            : Node_Id;
2875      New_Aspects           : List_Id;
2876      New_Id                : Entity_Id;
2877      New_N                 : Node_Id;
2878      New_Subtyp_Decl_For_L : Node_Id;
2879      System                : System_Type;
2880
2881   begin
2882      --  Case when the operand is not dimensionless
2883
2884      if Exists (Dims_Of_N) then
2885
2886         --  Get the corresponding System_Type to know the exact number of
2887         --  dimensions in the system.
2888
2889         System := System_Of (Btyp_Of_L);
2890
2891         --  Generation of a new subtype with the proper dimensions
2892
2893         --  In order to rewrite the operator as a type conversion, a new
2894         --  dimensioned subtype with the resulting dimensions of the
2895         --  exponentiation must be created.
2896
2897         --  Generate:
2898
2899         --  Btyp_Of_L   : constant Entity_Id := Base_Type (Etyp_Of_L);
2900         --  System      : constant System_Id :=
2901         --                  Get_Dimension_System_Id (Btyp_Of_L);
2902         --  Num_Of_Dims : constant Number_Of_Dimensions :=
2903         --                  Dimension_Systems.Table (System).Dimension_Count;
2904
2905         --  subtype T is Btyp_Of_L
2906         --    with
2907         --      Dimension => (
2908         --        Dims_Of_N (1).Numerator / Dims_Of_N (1).Denominator,
2909         --        Dims_Of_N (2).Numerator / Dims_Of_N (2).Denominator,
2910         --        ...
2911         --        Dims_Of_N (Num_Of_Dims).Numerator /
2912         --          Dims_Of_N (Num_Of_Dims).Denominator);
2913
2914         --  Step 1: Generate the new aggregate for the aspect Dimension
2915
2916         New_Aspects  := Empty_List;
2917
2918         List_Of_Dims := New_List;
2919         for Position in Dims_Of_N'First .. System.Count loop
2920            Dim_Power := Dims_Of_N (Position);
2921            Append_To (List_Of_Dims,
2922               Make_Op_Divide (Loc,
2923                 Left_Opnd  =>
2924                   Make_Integer_Literal (Loc, Int (Dim_Power.Numerator)),
2925                 Right_Opnd =>
2926                   Make_Integer_Literal (Loc, Int (Dim_Power.Denominator))));
2927         end loop;
2928
2929         --  Step 2: Create the new Aspect Specification for Aspect Dimension
2930
2931         New_Aspect :=
2932           Make_Aspect_Specification (Loc,
2933             Identifier => Make_Identifier (Loc, Name_Dimension),
2934             Expression => Make_Aggregate (Loc, Expressions => List_Of_Dims));
2935
2936         --  Step 3: Make a temporary identifier for the new subtype
2937
2938         New_Id := Make_Temporary (Loc, 'T');
2939         Set_Is_Internal (New_Id);
2940
2941         --  Step 4: Declaration of the new subtype
2942
2943         New_Subtyp_Decl_For_L :=
2944            Make_Subtype_Declaration (Loc,
2945               Defining_Identifier => New_Id,
2946               Subtype_Indication  => New_Occurrence_Of (Btyp_Of_L, Loc));
2947
2948         Append (New_Aspect, New_Aspects);
2949         Set_Parent (New_Aspects, New_Subtyp_Decl_For_L);
2950         Set_Aspect_Specifications (New_Subtyp_Decl_For_L, New_Aspects);
2951
2952         Analyze (New_Subtyp_Decl_For_L);
2953
2954      --  Case where the operand is dimensionless
2955
2956      else
2957         New_Id := Btyp_Of_L;
2958      end if;
2959
2960      --  Replacement of N by New_N
2961
2962      --  Generate:
2963
2964      --  Actual_1 := Long_Long_Float (L),
2965
2966      --  Actual_2 := Long_Long_Float (Exponent_Value.Numerator) /
2967      --                Long_Long_Float (Exponent_Value.Denominator);
2968
2969      --  (T (Expon_LLF (Actual_1, Actual_2)));
2970
2971      --  where T is the subtype declared in step 1
2972
2973      --  The node is rewritten as a type conversion
2974
2975      --  Step 1: Creation of the two parameters of Expon_LLF function call
2976
2977      Actual_1 :=
2978        Make_Type_Conversion (Loc,
2979          Subtype_Mark => New_Occurrence_Of (Standard_Long_Long_Float, Loc),
2980          Expression   => Relocate_Node (L));
2981
2982      Actual_2 :=
2983        Make_Op_Divide (Loc,
2984          Left_Opnd  =>
2985            Make_Real_Literal (Loc,
2986              UR_From_Uint (UI_From_Int (Int (Exponent_Value.Numerator)))),
2987          Right_Opnd =>
2988            Make_Real_Literal (Loc,
2989              UR_From_Uint (UI_From_Int (Int (Exponent_Value.Denominator)))));
2990
2991      --  Step 2: Creation of New_N
2992
2993      New_N :=
2994         Make_Type_Conversion (Loc,
2995           Subtype_Mark => New_Occurrence_Of (New_Id, Loc),
2996           Expression   =>
2997             Make_Function_Call (Loc,
2998               Name => New_Occurrence_Of (RTE (RE_Expon_LLF), Loc),
2999               Parameter_Associations => New_List (
3000                 Actual_1, Actual_2)));
3001
3002      --  Step 3: Rewrite N with the result
3003
3004      Rewrite (N, New_N);
3005      Set_Etype (N, New_Id);
3006      Analyze_And_Resolve (N, New_Id);
3007   end Eval_Op_Expon_With_Rational_Exponent;
3008
3009   ------------
3010   -- Exists --
3011   ------------
3012
3013   function Exists (Dim : Dimension_Type) return Boolean is
3014   begin
3015      return Dim /= Null_Dimension;
3016   end Exists;
3017
3018   function Exists (Str : String_Id) return Boolean is
3019   begin
3020      return Str /= No_String;
3021   end Exists;
3022
3023   function Exists (Sys : System_Type) return Boolean is
3024   begin
3025      return Sys /= Null_System;
3026   end Exists;
3027
3028   ---------------------------------
3029   -- Expand_Put_Call_With_Symbol --
3030   ---------------------------------
3031
3032   --  For procedure Put (resp. Put_Dim_Of) and function Image, defined in
3033   --  System.Dim.Float_IO or System.Dim.Integer_IO, the default string
3034   --  parameter is rewritten to include the unit symbol (or the dimension
3035   --  symbols if not a defined quantity) in the output of a dimensioned
3036   --  object. If a value is already supplied by the user for the parameter
3037   --  Symbol, it is used as is.
3038
3039   --  Case 1. Item is dimensionless
3040
3041   --   * Put        : Item appears without a suffix
3042
3043   --   * Put_Dim_Of : the output is []
3044
3045   --      Obj : Mks_Type := 2.6;
3046   --      Put (Obj, 1, 1, 0);
3047   --      Put_Dim_Of (Obj);
3048
3049   --      The corresponding outputs are:
3050   --      $2.6
3051   --      $[]
3052
3053   --  Case 2. Item has a dimension
3054
3055   --   * Put        : If the type of Item is a dimensioned subtype whose
3056   --                  symbol is not empty, then the symbol appears as a
3057   --                  suffix. Otherwise, a new string is created and appears
3058   --                  as a suffix of Item. This string results in the
3059   --                  successive concatanations between each unit symbol
3060   --                  raised by its corresponding dimension power from the
3061   --                  dimensions of Item.
3062
3063   --   * Put_Dim_Of : The output is a new string resulting in the successive
3064   --                  concatanations between each dimension symbol raised by
3065   --                  its corresponding dimension power from the dimensions of
3066   --                  Item.
3067
3068   --      subtype Random is Mks_Type
3069   --        with
3070   --         Dimension => (
3071   --           Meter =>   3,
3072   --           Candela => -1,
3073   --           others =>  0);
3074
3075   --      Obj : Random := 5.0;
3076   --      Put (Obj);
3077   --      Put_Dim_Of (Obj);
3078
3079   --      The corresponding outputs are:
3080   --      $5.0 m**3.cd**(-1)
3081   --      $[l**3.J**(-1)]
3082
3083   --      The function Image returns the string identical to that produced by
3084   --      a call to Put whose first parameter is a string.
3085
3086   procedure Expand_Put_Call_With_Symbol (N : Node_Id) is
3087      Actuals        : constant List_Id := Parameter_Associations (N);
3088      Loc            : constant Source_Ptr := Sloc (N);
3089      Name_Call      : constant Node_Id := Name (N);
3090      New_Actuals    : constant List_Id := New_List;
3091      Actual         : Node_Id;
3092      Dims_Of_Actual : Dimension_Type;
3093      Etyp           : Entity_Id;
3094      New_Str_Lit    : Node_Id := Empty;
3095      Symbols        : String_Id;
3096
3097      Is_Put_Dim_Of : Boolean := False;
3098      --  This flag is used in order to differentiate routines Put and
3099      --  Put_Dim_Of. Set to True if the procedure is one of the Put_Dim_Of
3100      --  defined in System.Dim.Float_IO or System.Dim.Integer_IO.
3101
3102      function Has_Symbols return Boolean;
3103      --  Return True if the current Put call already has a parameter
3104      --  association for parameter "Symbols" with the correct string of
3105      --  symbols.
3106
3107      function Is_Procedure_Put_Call return Boolean;
3108      --  Return True if the current call is a call of an instantiation of a
3109      --  procedure Put defined in the package System.Dim.Float_IO and
3110      --  System.Dim.Integer_IO.
3111
3112      function Item_Actual return Node_Id;
3113      --  Return the item actual parameter node in the output call
3114
3115      -----------------
3116      -- Has_Symbols --
3117      -----------------
3118
3119      function Has_Symbols return Boolean is
3120         Actual     : Node_Id;
3121         Actual_Str : Node_Id;
3122
3123      begin
3124         --  Look for a symbols parameter association in the list of actuals
3125
3126         Actual := First (Actuals);
3127         while Present (Actual) loop
3128
3129            --  Positional parameter association case when the actual is a
3130            --  string literal.
3131
3132            if Nkind (Actual) = N_String_Literal then
3133               Actual_Str := Actual;
3134
3135            --  Named parameter association case when selector name is Symbol
3136
3137            elsif Nkind (Actual) = N_Parameter_Association
3138              and then Chars (Selector_Name (Actual)) = Name_Symbol
3139            then
3140               Actual_Str := Explicit_Actual_Parameter (Actual);
3141
3142            --  Ignore all other cases
3143
3144            else
3145               Actual_Str := Empty;
3146            end if;
3147
3148            if Present (Actual_Str) then
3149
3150               --  Return True if the actual comes from source or if the string
3151               --  of symbols doesn't have the default value (i.e. it is ""),
3152               --  in which case it is used as suffix of the generated string.
3153
3154               if Comes_From_Source (Actual)
3155                 or else String_Length (Strval (Actual_Str)) /= 0
3156               then
3157                  return True;
3158
3159               else
3160                  return False;
3161               end if;
3162            end if;
3163
3164            Next (Actual);
3165         end loop;
3166
3167         --  At this point, the call has no parameter association. Look to the
3168         --  last actual since the symbols parameter is the last one.
3169
3170         return Nkind (Last (Actuals)) = N_String_Literal;
3171      end Has_Symbols;
3172
3173      ---------------------------
3174      -- Is_Procedure_Put_Call --
3175      ---------------------------
3176
3177      function Is_Procedure_Put_Call return Boolean is
3178         Ent : Entity_Id;
3179         Loc : Source_Ptr;
3180
3181      begin
3182         --  There are three different Put (resp. Put_Dim_Of) routines in each
3183         --  generic dim IO package. Verify the current procedure call is one
3184         --  of them.
3185
3186         if Is_Entity_Name (Name_Call) then
3187            Ent := Entity (Name_Call);
3188
3189            --  Get the original subprogram entity following the renaming chain
3190
3191            if Present (Alias (Ent)) then
3192               Ent := Alias (Ent);
3193            end if;
3194
3195            Loc := Sloc (Ent);
3196
3197            --  Check the name of the entity subprogram is Put (resp.
3198            --  Put_Dim_Of) and verify this entity is located in either
3199            --  System.Dim.Float_IO or System.Dim.Integer_IO.
3200
3201            if Loc > No_Location
3202              and then Is_Dim_IO_Package_Entity
3203                         (Cunit_Entity (Get_Source_Unit (Loc)))
3204            then
3205               if Chars (Ent) = Name_Put_Dim_Of then
3206                  Is_Put_Dim_Of := True;
3207                  return True;
3208
3209               elsif Chars (Ent) = Name_Put
3210                 or else Chars (Ent) = Name_Image
3211               then
3212                  return True;
3213               end if;
3214            end if;
3215         end if;
3216
3217         return False;
3218      end Is_Procedure_Put_Call;
3219
3220      -----------------
3221      -- Item_Actual --
3222      -----------------
3223
3224      function Item_Actual return Node_Id is
3225         Actual : Node_Id;
3226
3227      begin
3228         --  Look for the item actual as a parameter association
3229
3230         Actual := First (Actuals);
3231         while Present (Actual) loop
3232            if Nkind (Actual) = N_Parameter_Association
3233              and then Chars (Selector_Name (Actual)) = Name_Item
3234            then
3235               return Explicit_Actual_Parameter (Actual);
3236            end if;
3237
3238            Next (Actual);
3239         end loop;
3240
3241         --  Case where the item has been defined without an association
3242
3243         Actual := First (Actuals);
3244
3245         --  Depending on the procedure Put, Item actual could be first or
3246         --  second in the list of actuals.
3247
3248         if Has_Dimension_System (Base_Type (Etype (Actual))) then
3249            return Actual;
3250         else
3251            return Next (Actual);
3252         end if;
3253      end Item_Actual;
3254
3255   --  Start of processing for Expand_Put_Call_With_Symbol
3256
3257   begin
3258      if Is_Procedure_Put_Call and then not Has_Symbols then
3259         Actual := Item_Actual;
3260         Dims_Of_Actual := Dimensions_Of (Actual);
3261         Etyp := Etype (Actual);
3262
3263         --  Put_Dim_Of case
3264
3265         if Is_Put_Dim_Of then
3266
3267            --  Check that the item is not dimensionless
3268
3269            --  Create the new String_Literal with the new String_Id generated
3270            --  by the routine From_Dim_To_Str_Of_Dim_Symbols.
3271
3272            if Exists (Dims_Of_Actual) then
3273               New_Str_Lit :=
3274                 Make_String_Literal (Loc,
3275                   From_Dim_To_Str_Of_Dim_Symbols
3276                     (Dims_Of_Actual, System_Of (Base_Type (Etyp))));
3277
3278            --  If dimensionless, the output is []
3279
3280            else
3281               New_Str_Lit :=
3282                 Make_String_Literal (Loc, "[]");
3283            end if;
3284
3285         --  Put case
3286
3287         else
3288            --  Add the symbol as a suffix of the value if the subtype has a
3289            --  unit symbol or if the parameter is not dimensionless.
3290
3291            if Exists (Symbol_Of (Etyp)) then
3292               Symbols := Symbol_Of (Etyp);
3293            else
3294               Symbols := From_Dim_To_Str_Of_Unit_Symbols
3295                            (Dims_Of_Actual, System_Of (Base_Type (Etyp)));
3296            end if;
3297
3298            --  Check Symbols exists
3299
3300            if Exists (Symbols) then
3301               Start_String;
3302
3303               --  Put a space between the value and the dimension
3304
3305               Store_String_Char (' ');
3306               Store_String_Chars (Symbols);
3307               New_Str_Lit := Make_String_Literal (Loc, End_String);
3308            end if;
3309         end if;
3310
3311         if Present (New_Str_Lit) then
3312
3313            --  Insert all actuals in New_Actuals
3314
3315            Actual := First (Actuals);
3316            while Present (Actual) loop
3317
3318               --  Copy every actuals in New_Actuals except the Symbols
3319               --  parameter association.
3320
3321               if Nkind (Actual) = N_Parameter_Association
3322                 and then Chars (Selector_Name (Actual)) /= Name_Symbol
3323               then
3324                  Append_To (New_Actuals,
3325                     Make_Parameter_Association (Loc,
3326                        Selector_Name => New_Copy (Selector_Name (Actual)),
3327                        Explicit_Actual_Parameter =>
3328                           New_Copy (Explicit_Actual_Parameter (Actual))));
3329
3330               elsif Nkind (Actual) /= N_Parameter_Association then
3331                  Append_To (New_Actuals, New_Copy (Actual));
3332               end if;
3333
3334               Next (Actual);
3335            end loop;
3336
3337            --  Create new Symbols param association and append to New_Actuals
3338
3339            Append_To (New_Actuals,
3340              Make_Parameter_Association (Loc,
3341                Selector_Name => Make_Identifier (Loc, Name_Symbol),
3342                Explicit_Actual_Parameter => New_Str_Lit));
3343
3344            --  Rewrite and analyze the procedure call
3345
3346            if Chars (Name_Call) = Name_Image then
3347               Rewrite (N,
3348                 Make_Function_Call (Loc,
3349                   Name =>                   New_Copy (Name_Call),
3350                   Parameter_Associations => New_Actuals));
3351               Analyze_And_Resolve (N);
3352            else
3353               Rewrite (N,
3354                 Make_Procedure_Call_Statement (Loc,
3355                   Name =>                   New_Copy (Name_Call),
3356                   Parameter_Associations => New_Actuals));
3357               Analyze (N);
3358            end if;
3359
3360         end if;
3361      end if;
3362   end Expand_Put_Call_With_Symbol;
3363
3364   ------------------------------------
3365   -- From_Dim_To_Str_Of_Dim_Symbols --
3366   ------------------------------------
3367
3368   --  Given a dimension vector and the corresponding dimension system, create
3369   --  a String_Id to output dimension symbols corresponding to the dimensions
3370   --  Dims. If In_Error_Msg is True, there is a special handling for character
3371   --  asterisk * which is an insertion character in error messages.
3372
3373   function From_Dim_To_Str_Of_Dim_Symbols
3374     (Dims         : Dimension_Type;
3375      System       : System_Type;
3376      In_Error_Msg : Boolean := False) return String_Id
3377   is
3378      Dim_Power : Rational;
3379      First_Dim : Boolean := True;
3380
3381      procedure Store_String_Oexpon;
3382      --  Store the expon operator symbol "**" in the string. In error
3383      --  messages, asterisk * is a special character and must be quoted
3384      --  to be placed literally into the message.
3385
3386      -------------------------
3387      -- Store_String_Oexpon --
3388      -------------------------
3389
3390      procedure Store_String_Oexpon is
3391      begin
3392         if In_Error_Msg then
3393            Store_String_Chars ("'*'*");
3394         else
3395            Store_String_Chars ("**");
3396         end if;
3397      end Store_String_Oexpon;
3398
3399   --  Start of processing for From_Dim_To_Str_Of_Dim_Symbols
3400
3401   begin
3402      --  Initialization of the new String_Id
3403
3404      Start_String;
3405
3406      --  Store the dimension symbols inside boxes
3407
3408      if In_Error_Msg then
3409         Store_String_Chars ("'[");
3410      else
3411         Store_String_Char ('[');
3412      end if;
3413
3414      for Position in Dimension_Type'Range loop
3415         Dim_Power := Dims (Position);
3416         if Dim_Power /= Zero then
3417
3418            if First_Dim then
3419               First_Dim := False;
3420            else
3421               Store_String_Char ('.');
3422            end if;
3423
3424            Store_String_Chars (System.Dim_Symbols (Position));
3425
3426            --  Positive dimension case
3427
3428            if Dim_Power.Numerator > 0 then
3429
3430               --  Integer case
3431
3432               if Dim_Power.Denominator = 1 then
3433                  if Dim_Power.Numerator /= 1 then
3434                     Store_String_Oexpon;
3435                     Store_String_Int (Int (Dim_Power.Numerator));
3436                  end if;
3437
3438               --  Rational case when denominator /= 1
3439
3440               else
3441                  Store_String_Oexpon;
3442                  Store_String_Char ('(');
3443                  Store_String_Int (Int (Dim_Power.Numerator));
3444                  Store_String_Char ('/');
3445                  Store_String_Int (Int (Dim_Power.Denominator));
3446                  Store_String_Char (')');
3447               end if;
3448
3449            --  Negative dimension case
3450
3451            else
3452               Store_String_Oexpon;
3453               Store_String_Char ('(');
3454               Store_String_Char ('-');
3455               Store_String_Int (Int (-Dim_Power.Numerator));
3456
3457               --  Integer case
3458
3459               if Dim_Power.Denominator = 1 then
3460                  Store_String_Char (')');
3461
3462               --  Rational case when denominator /= 1
3463
3464               else
3465                  Store_String_Char ('/');
3466                  Store_String_Int (Int (Dim_Power.Denominator));
3467                  Store_String_Char (')');
3468               end if;
3469            end if;
3470         end if;
3471      end loop;
3472
3473      if In_Error_Msg then
3474         Store_String_Chars ("']");
3475      else
3476         Store_String_Char (']');
3477      end if;
3478
3479      return End_String;
3480   end From_Dim_To_Str_Of_Dim_Symbols;
3481
3482   -------------------------------------
3483   -- From_Dim_To_Str_Of_Unit_Symbols --
3484   -------------------------------------
3485
3486   --  Given a dimension vector and the corresponding dimension system,
3487   --  create a String_Id to output the unit symbols corresponding to the
3488   --  dimensions Dims.
3489
3490   function From_Dim_To_Str_Of_Unit_Symbols
3491     (Dims   : Dimension_Type;
3492      System : System_Type) return String_Id
3493   is
3494      Dim_Power : Rational;
3495      First_Dim : Boolean := True;
3496
3497   begin
3498      --  Return No_String if dimensionless
3499
3500      if not Exists (Dims) then
3501         return No_String;
3502      end if;
3503
3504      --  Initialization of the new String_Id
3505
3506      Start_String;
3507
3508      for Position in Dimension_Type'Range loop
3509         Dim_Power := Dims (Position);
3510
3511         if Dim_Power /= Zero then
3512            if First_Dim then
3513               First_Dim := False;
3514            else
3515               Store_String_Char ('.');
3516            end if;
3517
3518            Store_String_Chars (System.Unit_Symbols (Position));
3519
3520            --  Positive dimension case
3521
3522            if Dim_Power.Numerator > 0 then
3523
3524               --  Integer case
3525
3526               if Dim_Power.Denominator = 1 then
3527                  if Dim_Power.Numerator /= 1 then
3528                     Store_String_Chars ("**");
3529                     Store_String_Int (Int (Dim_Power.Numerator));
3530                  end if;
3531
3532               --  Rational case when denominator /= 1
3533
3534               else
3535                  Store_String_Chars ("**");
3536                  Store_String_Char ('(');
3537                  Store_String_Int (Int (Dim_Power.Numerator));
3538                  Store_String_Char ('/');
3539                  Store_String_Int (Int (Dim_Power.Denominator));
3540                  Store_String_Char (')');
3541               end if;
3542
3543            --  Negative dimension case
3544
3545            else
3546               Store_String_Chars ("**");
3547               Store_String_Char ('(');
3548               Store_String_Char ('-');
3549               Store_String_Int (Int (-Dim_Power.Numerator));
3550
3551               --  Integer case
3552
3553               if Dim_Power.Denominator = 1 then
3554                  Store_String_Char (')');
3555
3556               --  Rational case when denominator /= 1
3557
3558               else
3559                  Store_String_Char ('/');
3560                  Store_String_Int (Int (Dim_Power.Denominator));
3561                  Store_String_Char (')');
3562               end if;
3563            end if;
3564         end if;
3565      end loop;
3566
3567      return End_String;
3568   end From_Dim_To_Str_Of_Unit_Symbols;
3569
3570   ---------
3571   -- GCD --
3572   ---------
3573
3574   function GCD (Left, Right : Whole) return Int is
3575      L : Whole;
3576      R : Whole;
3577
3578   begin
3579      L := Left;
3580      R := Right;
3581      while R /= 0 loop
3582         L := L mod R;
3583
3584         if L = 0 then
3585            return Int (R);
3586         end if;
3587
3588         R := R mod L;
3589      end loop;
3590
3591      return Int (L);
3592   end GCD;
3593
3594   --------------------------
3595   -- Has_Dimension_System --
3596   --------------------------
3597
3598   function Has_Dimension_System (Typ : Entity_Id) return Boolean is
3599   begin
3600      return Exists (System_Of (Typ));
3601   end Has_Dimension_System;
3602
3603   ------------------------------
3604   -- Is_Dim_IO_Package_Entity --
3605   ------------------------------
3606
3607   function Is_Dim_IO_Package_Entity (E : Entity_Id) return Boolean is
3608   begin
3609      --  Check the package entity corresponds to System.Dim.Float_IO or
3610      --  System.Dim.Integer_IO.
3611
3612      return
3613        Is_RTU (E, System_Dim_Float_IO)
3614          or else
3615        Is_RTU (E, System_Dim_Integer_IO);
3616   end Is_Dim_IO_Package_Entity;
3617
3618   -------------------------------------
3619   -- Is_Dim_IO_Package_Instantiation --
3620   -------------------------------------
3621
3622   function Is_Dim_IO_Package_Instantiation (N : Node_Id) return Boolean is
3623      Gen_Id : constant Node_Id := Name (N);
3624
3625   begin
3626      --  Check that the instantiated package is either System.Dim.Float_IO
3627      --  or System.Dim.Integer_IO.
3628
3629      return
3630        Is_Entity_Name (Gen_Id)
3631          and then Is_Dim_IO_Package_Entity (Entity (Gen_Id));
3632   end Is_Dim_IO_Package_Instantiation;
3633
3634   ----------------
3635   -- Is_Invalid --
3636   ----------------
3637
3638   function Is_Invalid (Position : Dimension_Position) return Boolean is
3639   begin
3640      return Position = Invalid_Position;
3641   end Is_Invalid;
3642
3643   ---------------------
3644   -- Move_Dimensions --
3645   ---------------------
3646
3647   procedure Move_Dimensions (From, To : Node_Id) is
3648   begin
3649      if Ada_Version < Ada_2012 then
3650         return;
3651      end if;
3652
3653      --  Copy the dimension of 'From to 'To' and remove dimension of 'From'
3654
3655      Copy_Dimensions   (From, To);
3656      Remove_Dimensions (From);
3657   end Move_Dimensions;
3658
3659   ---------------------------------------
3660   -- New_Copy_Tree_And_Copy_Dimensions --
3661   ---------------------------------------
3662
3663   function New_Copy_Tree_And_Copy_Dimensions
3664     (Source    : Node_Id;
3665      Map       : Elist_Id   := No_Elist;
3666      New_Sloc  : Source_Ptr := No_Location;
3667      New_Scope : Entity_Id  := Empty) return Node_Id
3668   is
3669      New_Copy : constant Node_Id :=
3670                   New_Copy_Tree (Source, Map, New_Sloc, New_Scope);
3671
3672   begin
3673      --  Move the dimensions of Source to New_Copy
3674
3675      Copy_Dimensions (Source, New_Copy);
3676      return New_Copy;
3677   end New_Copy_Tree_And_Copy_Dimensions;
3678
3679   ------------
3680   -- Reduce --
3681   ------------
3682
3683   function Reduce (X : Rational) return Rational is
3684   begin
3685      if X.Numerator = 0 then
3686         return Zero;
3687      end if;
3688
3689      declare
3690         G : constant Int := GCD (X.Numerator, X.Denominator);
3691      begin
3692         return Rational'(Numerator =>   Whole (Int (X.Numerator)   / G),
3693                          Denominator => Whole (Int (X.Denominator) / G));
3694      end;
3695   end Reduce;
3696
3697   -----------------------
3698   -- Remove_Dimensions --
3699   -----------------------
3700
3701   procedure Remove_Dimensions (N : Node_Id) is
3702      Dims_Of_N : constant Dimension_Type := Dimensions_Of (N);
3703   begin
3704      if Exists (Dims_Of_N) then
3705         Dimension_Table.Remove (N);
3706      end if;
3707   end Remove_Dimensions;
3708
3709   -----------------------------------
3710   -- Remove_Dimension_In_Statement --
3711   -----------------------------------
3712
3713   --  Removal of dimension in statement as part of the Analyze_Statements
3714   --  routine (see package Sem_Ch5).
3715
3716   procedure Remove_Dimension_In_Statement (Stmt : Node_Id) is
3717   begin
3718      if Ada_Version < Ada_2012 then
3719         return;
3720      end if;
3721
3722      --  Remove dimension in parameter specifications for accept statement
3723
3724      if Nkind (Stmt) = N_Accept_Statement then
3725         declare
3726            Param : Node_Id := First (Parameter_Specifications (Stmt));
3727         begin
3728            while Present (Param) loop
3729               Remove_Dimensions (Param);
3730               Next (Param);
3731            end loop;
3732         end;
3733
3734      --  Remove dimension of name and expression in assignments
3735
3736      elsif Nkind (Stmt) = N_Assignment_Statement then
3737         Remove_Dimensions (Expression (Stmt));
3738         Remove_Dimensions (Name (Stmt));
3739      end if;
3740   end Remove_Dimension_In_Statement;
3741
3742   --------------------
3743   -- Set_Dimensions --
3744   --------------------
3745
3746   procedure Set_Dimensions (N : Node_Id; Val : Dimension_Type) is
3747   begin
3748      pragma Assert (OK_For_Dimension (Nkind (N)));
3749      pragma Assert (Exists (Val));
3750
3751      Dimension_Table.Set (N, Val);
3752   end Set_Dimensions;
3753
3754   ----------------
3755   -- Set_Symbol --
3756   ----------------
3757
3758   procedure Set_Symbol (E : Entity_Id; Val : String_Id) is
3759   begin
3760      Symbol_Table.Set (E, Val);
3761   end Set_Symbol;
3762
3763   ---------------------------------
3764   -- String_From_Numeric_Literal --
3765   ---------------------------------
3766
3767   function String_From_Numeric_Literal (N : Node_Id) return String_Id is
3768      Loc     : constant Source_Ptr        := Sloc (N);
3769      Sbuffer : constant Source_Buffer_Ptr :=
3770                  Source_Text (Get_Source_File_Index (Loc));
3771      Src_Ptr : Source_Ptr := Loc;
3772
3773      C : Character  := Sbuffer (Src_Ptr);
3774      --  Current source program character
3775
3776      function Belong_To_Numeric_Literal (C : Character) return Boolean;
3777      --  Return True if C belongs to a numeric literal
3778
3779      -------------------------------
3780      -- Belong_To_Numeric_Literal --
3781      -------------------------------
3782
3783      function Belong_To_Numeric_Literal (C : Character) return Boolean is
3784      begin
3785         case C is
3786            when '0' .. '9'
3787               | '_' | '.' | 'e' | '#' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F'
3788            =>
3789               return True;
3790
3791            --  Make sure '+' or '-' is part of an exponent.
3792
3793            when '+' | '-' =>
3794               declare
3795                  Prev_C : constant Character := Sbuffer (Src_Ptr - 1);
3796               begin
3797                  return Prev_C = 'e' or else Prev_C = 'E';
3798               end;
3799
3800            --  All other character doesn't belong to a numeric literal
3801
3802            when others =>
3803               return False;
3804         end case;
3805      end Belong_To_Numeric_Literal;
3806
3807   --  Start of processing for String_From_Numeric_Literal
3808
3809   begin
3810      Start_String;
3811      while Belong_To_Numeric_Literal (C) loop
3812         Store_String_Char (C);
3813         Src_Ptr := Src_Ptr + 1;
3814         C       := Sbuffer (Src_Ptr);
3815      end loop;
3816
3817      return End_String;
3818   end String_From_Numeric_Literal;
3819
3820   ---------------
3821   -- Symbol_Of --
3822   ---------------
3823
3824   function Symbol_Of (E : Entity_Id) return String_Id is
3825      Subtype_Symbol : constant String_Id := Symbol_Table.Get (E);
3826   begin
3827      if Subtype_Symbol /= No_String then
3828         return Subtype_Symbol;
3829      else
3830         return From_Dim_To_Str_Of_Unit_Symbols
3831                  (Dimensions_Of (E), System_Of (Base_Type (E)));
3832      end if;
3833   end Symbol_Of;
3834
3835   -----------------------
3836   -- Symbol_Table_Hash --
3837   -----------------------
3838
3839   function Symbol_Table_Hash (Key : Entity_Id) return Symbol_Table_Range is
3840   begin
3841      return Symbol_Table_Range (Key mod 511);
3842   end Symbol_Table_Hash;
3843
3844   ---------------
3845   -- System_Of --
3846   ---------------
3847
3848   function System_Of (E : Entity_Id) return System_Type is
3849      Type_Decl : constant Node_Id := Parent (E);
3850
3851   begin
3852      --  Look for Type_Decl in System_Table
3853
3854      for Dim_Sys in 1 .. System_Table.Last loop
3855         if Type_Decl = System_Table.Table (Dim_Sys).Type_Decl then
3856            return System_Table.Table (Dim_Sys);
3857         end if;
3858      end loop;
3859
3860      return Null_System;
3861   end System_Of;
3862
3863end Sem_Dim;
3864