1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
11 -- Copyright (C) 1996-2001 Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- GNAT was originally developed by the GNAT team at New York University. --
25 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
27 ------------------------------------------------------------------------------
29 with Atree; use Atree;
30 with Einfo; use Einfo;
31 with Errout; use Errout;
32 with Namet; use Namet;
33 with Nlists; use Nlists;
35 with Sem_Eval; use Sem_Eval;
36 with Sem_Res; use Sem_Res;
37 with Sem_Util; use Sem_Util;
38 with Sem_Type; use Sem_Type;
39 with Snames; use Snames;
40 with Stand; use Stand;
41 with Sinfo; use Sinfo;
42 with Uintp; use Uintp;
44 with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
46 package body Sem_Case is
48 -----------------------
49 -- Local Subprograms --
50 -----------------------
52 type Sort_Choice_Table_Type is array (Nat range <>) of Choice_Bounds;
53 -- This new array type is used as the actual table type for sorting
54 -- discrete choices. The reason for not using Choice_Table_Type, is that
55 -- in Sort_Choice_Table_Type we reserve entry 0 for the sorting algortim
56 -- (this is not absolutely necessary but it makes the code more
59 procedure Check_Choices
60 (Choice_Table : in out Sort_Choice_Table_Type;
61 Bounds_Type : Entity_Id;
62 Others_Present : Boolean;
63 Msg_Sloc : Source_Ptr);
64 -- This is the procedure which verifies that a set of case statement,
65 -- array aggregate or record variant choices has no duplicates, and
66 -- covers the range specified by Bounds_Type. Choice_Table contains the
67 -- discrete choices to check. These must start at position 1.
68 -- Furthermore Choice_Table (0) must exist. This element is used by
69 -- the sorting algorithm as a temporary. Others_Present is a flag
70 -- indicating whether or not an Others choice is present. Finally
71 -- Msg_Sloc gives the source location of the construct containing the
72 -- choices in the Choice_Table.
74 function Choice_Image (Value : Uint; Ctype : Entity_Id) return Name_Id;
75 -- Given a Pos value of enumeration type Ctype, returns the name
76 -- ID of an appropriate string to be used in error message output.
82 procedure Check_Choices
83 (Choice_Table : in out Sort_Choice_Table_Type;
84 Bounds_Type : Entity_Id;
85 Others_Present : Boolean;
86 Msg_Sloc : Source_Ptr)
89 function Lt_Choice (C1, C2 : Natural) return Boolean;
90 -- Comparison routine for comparing Choice_Table entries.
91 -- Use the lower bound of each Choice as the key.
93 procedure Move_Choice (From : Natural; To : Natural);
94 -- Move routine for sorting the Choice_Table.
96 procedure Issue_Msg (Value1 : Node_Id; Value2 : Node_Id);
97 procedure Issue_Msg (Value1 : Node_Id; Value2 : Uint);
98 procedure Issue_Msg (Value1 : Uint; Value2 : Node_Id);
99 procedure Issue_Msg (Value1 : Uint; Value2 : Uint);
100 -- Issue an error message indicating that there are missing choices,
101 -- followed by the image of the missing choices themselves which lie
102 -- between Value1 and Value2 inclusive.
108 procedure Issue_Msg (Value1 : Node_Id; Value2 : Node_Id) is
110 Issue_Msg (Expr_Value (Value1), Expr_Value (Value2));
113 procedure Issue_Msg (Value1 : Node_Id; Value2 : Uint) is
115 Issue_Msg (Expr_Value (Value1), Value2);
118 procedure Issue_Msg (Value1 : Uint; Value2 : Node_Id) is
120 Issue_Msg (Value1, Expr_Value (Value2));
123 procedure Issue_Msg (Value1 : Uint; Value2 : Uint) is
125 -- In some situations, we call this with a null range, and
126 -- obviously we don't want to complain in this case!
128 if Value1 > Value2 then
132 -- Case of only one value that is missing
134 if Value1 = Value2 then
135 if Is_Integer_Type (Bounds_Type) then
136 Error_Msg_Uint_1 := Value1;
137 Error_Msg ("missing case value: ^!", Msg_Sloc);
139 Error_Msg_Name_1 := Choice_Image (Value1, Bounds_Type);
140 Error_Msg ("missing case value: %!", Msg_Sloc);
143 -- More than one choice value, so print range of values
146 if Is_Integer_Type (Bounds_Type) then
147 Error_Msg_Uint_1 := Value1;
148 Error_Msg_Uint_2 := Value2;
149 Error_Msg ("missing case values: ^ .. ^!", Msg_Sloc);
151 Error_Msg_Name_1 := Choice_Image (Value1, Bounds_Type);
152 Error_Msg_Name_2 := Choice_Image (Value2, Bounds_Type);
153 Error_Msg ("missing case values: % .. %!", Msg_Sloc);
162 function Lt_Choice (C1, C2 : Natural) return Boolean is
165 Expr_Value (Choice_Table (Nat (C1)).Lo)
166 <= Expr_Value (Choice_Table (Nat (C2)).Lo);
173 procedure Move_Choice (From : Natural; To : Natural) is
175 Choice_Table (Nat (To)) := Choice_Table (Nat (From));
178 -- Variables local to Check_Choices
181 Bounds_Lo : constant Node_Id := Type_Low_Bound (Bounds_Type);
182 Bounds_Hi : constant Node_Id := Type_High_Bound (Bounds_Type);
184 Prev_Choice : Node_Id;
190 -- Start processing for Check_Choices
194 -- Choice_Table must start at 0 which is an unused location used
195 -- by the sorting algorithm. However the first valid position for
196 -- a discrete choice is 1.
198 pragma Assert (Choice_Table'First = 0);
200 if Choice_Table'Last = 0 then
201 if not Others_Present then
202 Issue_Msg (Bounds_Lo, Bounds_Hi);
208 (Positive (Choice_Table'Last),
209 Move_Choice'Unrestricted_Access,
210 Lt_Choice'Unrestricted_Access);
212 Lo := Expr_Value (Choice_Table (1).Lo);
213 Hi := Expr_Value (Choice_Table (1).Hi);
216 if not Others_Present and then Expr_Value (Bounds_Lo) < Lo then
217 Issue_Msg (Bounds_Lo, Lo - 1);
220 for J in 2 .. Choice_Table'Last loop
221 Lo := Expr_Value (Choice_Table (J).Lo);
222 Hi := Expr_Value (Choice_Table (J).Hi);
224 if Lo <= Prev_Hi then
225 Prev_Choice := Choice_Table (J - 1).Node;
226 Choice := Choice_Table (J).Node;
228 if Sloc (Prev_Choice) <= Sloc (Choice) then
229 Error_Msg_Sloc := Sloc (Prev_Choice);
230 Error_Msg_N ("duplication of choice value#", Choice);
232 Error_Msg_Sloc := Sloc (Choice);
233 Error_Msg_N ("duplication of choice value#", Prev_Choice);
236 elsif not Others_Present and then Lo /= Prev_Hi + 1 then
237 Issue_Msg (Prev_Hi + 1, Lo - 1);
243 if not Others_Present and then Expr_Value (Bounds_Hi) > Hi then
244 Issue_Msg (Hi + 1, Bounds_Hi);
252 function Choice_Image (Value : Uint; Ctype : Entity_Id) return Name_Id is
253 Rtp : constant Entity_Id := Root_Type (Ctype);
258 -- For character, or wide character. If we are in 7-bit ASCII graphic
259 -- range, then build and return appropriate character literal name
261 if Rtp = Standard_Character
262 or else Rtp = Standard_Wide_Character
264 C := UI_To_Int (Value);
266 if C in 16#20# .. 16#7E# then
267 Set_Character_Literal_Name (Char_Code (UI_To_Int (Value)));
271 -- For user defined enumeration type, find enum/char literal
274 Lit := First_Literal (Rtp);
276 for J in 1 .. UI_To_Int (Value) loop
280 -- If enumeration literal, just return its value
282 if Nkind (Lit) = N_Defining_Identifier then
285 -- For character literal, get the name and use it if it is
286 -- for a 7-bit ASCII graphic character in 16#20#..16#7E#.
289 Get_Decoded_Name_String (Chars (Lit));
292 and then Name_Buffer (2) in
293 Character'Val (16#20#) .. Character'Val (16#7E#)
300 -- If we fall through, we have a character literal which is not in
301 -- the 7-bit ASCII graphic set. For such cases, we construct the
302 -- name "type'val(nnn)" where type is the choice type, and nnn is
303 -- the pos value passed as an argument to Choice_Image.
305 Get_Name_String (Chars (First_Subtype (Ctype)));
306 Name_Len := Name_Len + 1;
307 Name_Buffer (Name_Len) := ''';
308 Name_Len := Name_Len + 1;
309 Name_Buffer (Name_Len) := 'v';
310 Name_Len := Name_Len + 1;
311 Name_Buffer (Name_Len) := 'a';
312 Name_Len := Name_Len + 1;
313 Name_Buffer (Name_Len) := 'l';
314 Name_Len := Name_Len + 1;
315 Name_Buffer (Name_Len) := '(';
319 for J in 1 .. UI_Image_Length loop
320 Name_Len := Name_Len + 1;
321 Name_Buffer (Name_Len) := UI_Image_Buffer (J);
324 Name_Len := Name_Len + 1;
325 Name_Buffer (Name_Len) := ')';
333 procedure No_OP (C : Node_Id) is
338 --------------------------------
339 -- Generic_Choices_Processing --
340 --------------------------------
342 package body Generic_Choices_Processing is
344 ---------------------
345 -- Analyze_Choices --
346 ---------------------
348 procedure Analyze_Choices
351 Choice_Table : in out Choice_Table_Type;
352 Last_Choice : out Nat;
353 Raises_CE : out Boolean;
354 Others_Present : out Boolean)
357 Nb_Choices : constant Nat := Choice_Table'Length;
358 Sort_Choice_Table : Sort_Choice_Table_Type (0 .. Nb_Choices);
360 Choice_Type : constant Entity_Id := Base_Type (Subtyp);
361 -- The actual type against which the discrete choices are
362 -- resolved. Note that this type is always the base type not the
363 -- subtype of the ruling expression, index or discriminant.
365 Bounds_Type : Entity_Id;
366 -- The type from which are derived the bounds of the values
367 -- covered by th discrete choices (see 3.8.1 (4)). If a discrete
368 -- choice specifies a value outside of these bounds we have an error.
372 -- The actual bounds of the above type.
374 Expected_Type : Entity_Id;
375 -- The expected type of each choice. Equal to Choice_Type, except
376 -- if the expression is universal, in which case the choices can
377 -- be of any integer type.
379 procedure Check (Choice : Node_Id; Lo, Hi : Node_Id);
380 -- Checks the validity of the bounds of a choice. When the bounds
381 -- are static and no error occurred the bounds are entered into
382 -- the choices table so that they can be sorted later on.
388 procedure Check (Choice : Node_Id; Lo, Hi : Node_Id) is
393 -- First check if an error was already detected on either bounds
395 if Etype (Lo) = Any_Type or else Etype (Hi) = Any_Type then
398 -- Do not insert non static choices in the table to be sorted
400 elsif not Is_Static_Expression (Lo)
401 or else not Is_Static_Expression (Hi)
403 Process_Non_Static_Choice (Choice);
406 -- Ignore range which raise constraint error
408 elsif Raises_Constraint_Error (Lo)
409 or else Raises_Constraint_Error (Hi)
414 -- Otherwise we have an OK static choice
417 Lo_Val := Expr_Value (Lo);
418 Hi_Val := Expr_Value (Hi);
420 -- Do not insert null ranges in the choices table
422 if Lo_Val > Hi_Val then
423 Process_Empty_Choice (Choice);
428 -- Check for bound out of range.
430 if Lo_Val < Bounds_Lo then
431 if Is_Integer_Type (Bounds_Type) then
432 Error_Msg_Uint_1 := Bounds_Lo;
433 Error_Msg_N ("minimum allowed choice value is^", Lo);
435 Error_Msg_Name_1 := Choice_Image (Bounds_Lo, Bounds_Type);
436 Error_Msg_N ("minimum allowed choice value is%", Lo);
439 elsif Hi_Val > Bounds_Hi then
440 if Is_Integer_Type (Bounds_Type) then
441 Error_Msg_Uint_1 := Bounds_Hi;
442 Error_Msg_N ("maximum allowed choice value is^", Hi);
444 Error_Msg_Name_1 := Choice_Image (Bounds_Hi, Bounds_Type);
445 Error_Msg_N ("maximum allowed choice value is%", Hi);
449 -- We still store the bounds in the table, even if they are out
450 -- of range, since this may prevent unnecessary cascaded errors
451 -- for values that are covered by such an excessive range.
453 Last_Choice := Last_Choice + 1;
454 Sort_Choice_Table (Last_Choice).Lo := Lo;
455 Sort_Choice_Table (Last_Choice).Hi := Hi;
456 Sort_Choice_Table (Last_Choice).Node := Choice;
459 -- Variables local to Analyze_Choices
462 -- A case statement alternative, an array aggregate component
463 -- association or a variant in a record type declaration
467 -- The node kind of the current Choice.
471 -- Start of processing for Analyze_Choices
476 Others_Present := False;
478 -- If Subtyp is not a static subtype Ada 95 requires then we use
479 -- the bounds of its base type to determine the values covered by
480 -- the discrete choices.
482 if Is_OK_Static_Subtype (Subtyp) then
483 Bounds_Type := Subtyp;
485 Bounds_Type := Choice_Type;
488 -- Obtain static bounds of type, unless this is a generic formal
489 -- discrete type for which all choices will be non-static.
491 if not Is_Generic_Type (Root_Type (Bounds_Type))
492 or else Ekind (Bounds_Type) /= E_Enumeration_Type
494 Bounds_Lo := Expr_Value (Type_Low_Bound (Bounds_Type));
495 Bounds_Hi := Expr_Value (Type_High_Bound (Bounds_Type));
498 if Choice_Type = Universal_Integer then
499 Expected_Type := Any_Integer;
501 Expected_Type := Choice_Type;
504 -- Now loop through the case statement alternatives or array
505 -- aggregate component associations or record variants.
507 Alt := First (Get_Alternatives (N));
508 while Present (Alt) loop
510 -- If pragma, just analyze it
512 if Nkind (Alt) = N_Pragma then
515 -- Otherwise check each choice against its base type
518 Choice := First (Get_Choices (Alt));
520 while Present (Choice) loop
522 Kind := Nkind (Choice);
527 or else (Kind = N_Attribute_Reference
528 and then Attribute_Name (Choice) = Name_Range)
530 Resolve (Choice, Expected_Type);
531 Check (Choice, Low_Bound (Choice), High_Bound (Choice));
533 -- Choice is a subtype name
535 elsif Is_Entity_Name (Choice)
536 and then Is_Type (Entity (Choice))
538 if not Covers (Expected_Type, Etype (Choice)) then
539 Wrong_Type (Choice, Choice_Type);
542 E := Entity (Choice);
544 if not Is_Static_Subtype (E) then
545 Process_Non_Static_Choice (Choice);
548 (Choice, Type_Low_Bound (E), Type_High_Bound (E));
552 -- Choice is a subtype indication
554 elsif Kind = N_Subtype_Indication then
555 Resolve_Discrete_Subtype_Indication
556 (Choice, Expected_Type);
558 if Etype (Choice) /= Any_Type then
560 C : constant Node_Id := Constraint (Choice);
561 R : constant Node_Id := Range_Expression (C);
562 L : constant Node_Id := Low_Bound (R);
563 H : constant Node_Id := High_Bound (R);
566 E := Entity (Subtype_Mark (Choice));
568 if not Is_Static_Subtype (E) then
569 Process_Non_Static_Choice (Choice);
572 if Is_OK_Static_Expression (L)
573 and then Is_OK_Static_Expression (H)
575 if Expr_Value (L) > Expr_Value (H) then
576 Process_Empty_Choice (Choice);
578 if Is_Out_Of_Range (L, E) then
579 Apply_Compile_Time_Constraint_Error
580 (L, "static value out of range");
583 if Is_Out_Of_Range (H, E) then
584 Apply_Compile_Time_Constraint_Error
585 (H, "static value out of range");
590 Check (Choice, L, H);
595 -- The others choice is only allowed for the last
596 -- alternative and as its only choice.
598 elsif Kind = N_Others_Choice then
599 if not (Choice = First (Get_Choices (Alt))
600 and then Choice = Last (Get_Choices (Alt))
601 and then Alt = Last (Get_Alternatives (N)))
604 ("the choice OTHERS must appear alone and last",
609 Others_Present := True;
611 -- Only other possibility is an expression
614 Resolve (Choice, Expected_Type);
615 Check (Choice, Choice, Choice);
621 Process_Associated_Node (Alt);
628 (Sort_Choice_Table (0 .. Last_Choice),
630 Others_Present or else (Choice_Type = Universal_Integer),
633 -- Now copy the sorted discrete choices
635 for J in 1 .. Last_Choice loop
636 Choice_Table (Choice_Table'First - 1 + J) := Sort_Choice_Table (J);
641 -----------------------
642 -- Number_Of_Choices --
643 -----------------------
645 function Number_Of_Choices (N : Node_Id) return Nat is
647 -- A case statement alternative, an array aggregate component
648 -- association or a record variant.
654 if not Present (Get_Alternatives (N)) then
658 Alt := First_Non_Pragma (Get_Alternatives (N));
659 while Present (Alt) loop
661 Choice := First (Get_Choices (Alt));
662 while Present (Choice) loop
663 if Nkind (Choice) /= N_Others_Choice then
670 Next_Non_Pragma (Alt);
674 end Number_Of_Choices;
676 end Generic_Choices_Processing;