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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [gcc/] [ada/] [scn.adb] - Blame information for rev 706

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1 706 jeremybenn
------------------------------------------------------------------------------
2
--                                                                          --
3
--                         GNAT COMPILER COMPONENTS                         --
4
--                                                                          --
5
--                                  S C N                                   --
6
--                                                                          --
7
--                                 B o d y                                  --
8
--                                                                          --
9
--          Copyright (C) 1992-2012, Free Software Foundation, Inc.         --
10
--                                                                          --
11
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12
-- terms of the  GNU General Public License as published  by the Free Soft- --
13
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17
-- for  more details.  You should have  received  a copy of the GNU General --
18
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
19
-- http://www.gnu.org/licenses for a complete copy of the license.          --
20
--                                                                          --
21
-- GNAT was originally developed  by the GNAT team at  New York University. --
22
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
23
--                                                                          --
24
------------------------------------------------------------------------------
25
 
26
with Atree;    use Atree;
27
with Csets;    use Csets;
28
with Hostparm; use Hostparm;
29
with Namet;    use Namet;
30
with Opt;      use Opt;
31
with Restrict; use Restrict;
32
with Rident;   use Rident;
33
with Scans;    use Scans;
34
with Sinfo;    use Sinfo;
35
with Sinput;   use Sinput;
36
with Uintp;    use Uintp;
37
 
38
package body Scn is
39
 
40
   use ASCII;
41
 
42
   Used_As_Identifier : array (Token_Type) of Boolean;
43
   --  Flags set True if a given keyword is used as an identifier (used to
44
   --  make sure that we only post an error message for incorrect use of a
45
   --  keyword as an identifier once for a given keyword).
46
 
47
   procedure Check_End_Of_Line;
48
   --  Called when end of line encountered. Checks that line is not too long,
49
   --  and that other style checks for the end of line are met.
50
 
51
   function Determine_License return License_Type;
52
   --  Scan header of file and check that it has an appropriate GNAT-style
53
   --  header with a proper license statement. Returns GPL, Unrestricted,
54
   --  or Modified_GPL depending on header. If none of these, returns Unknown.
55
 
56
   procedure Error_Long_Line;
57
   --  Signal error of excessively long line
58
 
59
   -----------------------
60
   -- Check_End_Of_Line --
61
   -----------------------
62
 
63
   procedure Check_End_Of_Line is
64
      Len : constant Int := Int (Scan_Ptr) - Int (Current_Line_Start);
65
   begin
66
      if Style_Check then
67
         Style.Check_Line_Terminator (Len);
68
      elsif Len > Max_Line_Length then
69
         Error_Long_Line;
70
      end if;
71
   end Check_End_Of_Line;
72
 
73
   -----------------------
74
   -- Determine_License --
75
   -----------------------
76
 
77
   function Determine_License return License_Type is
78
      GPL_Found : Boolean := False;
79
      Result    : License_Type;
80
 
81
      function Contains (S : String) return Boolean;
82
      --  See if current comment contains successive non-blank characters
83
      --  matching the contents of S. If so leave Scan_Ptr unchanged and
84
      --  return True, otherwise leave Scan_Ptr unchanged and return False.
85
 
86
      procedure Skip_EOL;
87
      --  Skip to line terminator character
88
 
89
      --------------
90
      -- Contains --
91
      --------------
92
 
93
      function Contains (S : String) return Boolean is
94
         CP : Natural;
95
         SP : Source_Ptr;
96
         SS : Source_Ptr;
97
 
98
      begin
99
         --  Loop to check characters. This loop is terminated by end of
100
         --  line, and also we need to check for the EOF case, to take
101
         --  care of files containing only comments.
102
 
103
         SP := Scan_Ptr;
104
         while Source (SP) /= CR and then
105
               Source (SP) /= LF and then
106
               Source (SP) /= EOF
107
         loop
108
            if Source (SP) = S (S'First) then
109
               SS := SP;
110
               CP := S'First;
111
 
112
               loop
113
                  SS := SS + 1;
114
                  CP := CP + 1;
115
 
116
                  if CP > S'Last then
117
                     return True;
118
                  end if;
119
 
120
                  while Source (SS) = ' ' loop
121
                     SS := SS + 1;
122
                  end loop;
123
 
124
                  exit when Source (SS) /= S (CP);
125
               end loop;
126
            end if;
127
 
128
            SP := SP + 1;
129
         end loop;
130
 
131
         return False;
132
      end Contains;
133
 
134
      --------------
135
      -- Skip_EOL --
136
      --------------
137
 
138
      procedure Skip_EOL is
139
      begin
140
         while Source (Scan_Ptr) /= CR
141
           and then Source (Scan_Ptr) /= LF
142
           and then Source (Scan_Ptr) /= EOF
143
         loop
144
            Scan_Ptr := Scan_Ptr + 1;
145
         end loop;
146
      end Skip_EOL;
147
 
148
   --  Start of processing for Determine_License
149
 
150
   begin
151
      loop
152
         if Source (Scan_Ptr) /= '-'
153
           or else Source (Scan_Ptr + 1) /= '-'
154
         then
155
            if GPL_Found then
156
               Result := GPL;
157
               exit;
158
            else
159
               Result := Unknown;
160
               exit;
161
            end if;
162
 
163
         elsif Contains ("Asaspecialexception") then
164
            if GPL_Found then
165
               Result := Modified_GPL;
166
               exit;
167
            end if;
168
 
169
         elsif Contains ("GNUGeneralPublicLicense") then
170
            GPL_Found := True;
171
 
172
         elsif
173
             Contains
174
               ("ThisspecificationisadaptedfromtheAdaSemanticInterface")
175
           or else
176
             Contains
177
              ("ThisspecificationisderivedfromtheAdaReferenceManual")
178
         then
179
            Result := Unrestricted;
180
            exit;
181
         end if;
182
 
183
         Skip_EOL;
184
 
185
         Check_End_Of_Line;
186
 
187
         if Source (Scan_Ptr) /= EOF then
188
 
189
            --  We have to take into account a degenerate case when the source
190
            --  file contains only comments and no Ada code.
191
 
192
            declare
193
               Physical : Boolean;
194
 
195
            begin
196
               Skip_Line_Terminators (Scan_Ptr, Physical);
197
 
198
               --  If we are at start of physical line, update scan pointers
199
               --  to reflect the start of the new line.
200
 
201
               if Physical then
202
                  Current_Line_Start       := Scan_Ptr;
203
                  Start_Column             := Scanner.Set_Start_Column;
204
                  First_Non_Blank_Location := Scan_Ptr;
205
               end if;
206
            end;
207
         end if;
208
      end loop;
209
 
210
      return Result;
211
   end Determine_License;
212
 
213
   ----------------------------
214
   -- Determine_Token_Casing --
215
   ----------------------------
216
 
217
   function Determine_Token_Casing return Casing_Type is
218
   begin
219
      return Scanner.Determine_Token_Casing;
220
   end Determine_Token_Casing;
221
 
222
   ---------------------
223
   -- Error_Long_Line --
224
   ---------------------
225
 
226
   procedure Error_Long_Line is
227
   begin
228
      Error_Msg
229
        ("this line is too long",
230
         Current_Line_Start + Source_Ptr (Max_Line_Length));
231
   end Error_Long_Line;
232
 
233
   ------------------------
234
   -- Initialize_Scanner --
235
   ------------------------
236
 
237
   procedure Initialize_Scanner
238
     (Unit  : Unit_Number_Type;
239
      Index : Source_File_Index)
240
   is
241
      GNAT_Hedr : constant Text_Buffer (1 .. 78) := (others => '-');
242
 
243
   begin
244
      Scanner.Initialize_Scanner (Index);
245
 
246
      if Index /= Internal_Source_File then
247
         Set_Unit (Index, Unit);
248
      end if;
249
 
250
      Current_Source_Unit := Unit;
251
 
252
      --  Set default for Comes_From_Source (except if we are going to process
253
      --  an artificial string internally created within the compiler and
254
      --  placed into internal source duffer). All nodes built now until we
255
      --  reenter the analyzer will have Comes_From_Source set to True
256
 
257
      if Index /= Internal_Source_File then
258
         Set_Comes_From_Source_Default (True);
259
      end if;
260
 
261
      --  Check license if GNAT type header possibly present
262
 
263
      if Source_Last (Index) - Scan_Ptr > 80
264
        and then Source (Scan_Ptr .. Scan_Ptr + 77) = GNAT_Hedr
265
      then
266
         Set_License (Current_Source_File, Determine_License);
267
      end if;
268
 
269
      Check_For_BOM;
270
 
271
      --  Because of the License stuff above, Scng.Initialize_Scanner cannot
272
      --  call Scan. Scan initial token (note this initializes Prev_Token,
273
      --  Prev_Token_Ptr).
274
 
275
      --  There are two reasons not to do the Scan step in case if we
276
      --  initialize the scanner for the internal source buffer:
277
 
278
      --  - The artificial string may not be created by the compiler in this
279
      --    buffer when we call Initialize_Scanner
280
 
281
      --  - For these artificial strings a special way of scanning is used, so
282
      --    the standard step of the scanner may just break the algorithm of
283
      --    processing these strings.
284
 
285
      if Index /= Internal_Source_File then
286
         Scan;
287
      end if;
288
 
289
      --  Clear flags for reserved words used as identifiers
290
 
291
      for J in Token_Type loop
292
         Used_As_Identifier (J) := False;
293
      end loop;
294
   end Initialize_Scanner;
295
 
296
   ---------------
297
   -- Post_Scan --
298
   ---------------
299
 
300
   procedure Post_Scan is
301
      procedure Check_Obsolescent_Features_Restriction (S : Source_Ptr);
302
      --  This checks for Obsolescent_Features restriction being active, and
303
      --  if so, flags the restriction as occurring at the given scan location.
304
 
305
      procedure Check_Obsolete_Base_Char;
306
      --  Check for numeric literal using ':' instead of '#' for based case
307
 
308
      --------------------------------------------
309
      -- Check_Obsolescent_Features_Restriction --
310
      --------------------------------------------
311
 
312
      procedure Check_Obsolescent_Features_Restriction (S : Source_Ptr) is
313
      begin
314
         --  Normally we have a node handy for posting restrictions. We don't
315
         --  have such a node here, so construct a dummy one with the right
316
         --  scan pointer. This is only used to get the Sloc value anyway.
317
 
318
         Check_Restriction (No_Obsolescent_Features, New_Node (N_Empty, S));
319
      end Check_Obsolescent_Features_Restriction;
320
 
321
      ------------------------------
322
      -- Check_Obsolete_Base_Char --
323
      ------------------------------
324
 
325
      procedure Check_Obsolete_Base_Char is
326
         S : Source_Ptr;
327
 
328
      begin
329
         if Based_Literal_Uses_Colon then
330
 
331
            --  Find the : for the restriction or warning message
332
 
333
            S := Token_Ptr;
334
            while Source (S) /= ':' loop
335
               S := S + 1;
336
            end loop;
337
 
338
            Check_Obsolescent_Features_Restriction (S);
339
 
340
            if Warn_On_Obsolescent_Feature then
341
               Error_Msg
342
                 ("use of "":"" is an obsolescent feature (RM J.2(3))?", S);
343
               Error_Msg
344
                 ("\use ""'#"" instead?", S);
345
            end if;
346
         end if;
347
      end Check_Obsolete_Base_Char;
348
 
349
   --  Start of processing for Post_Scan
350
 
351
   begin
352
      case Token is
353
         when Tok_Char_Literal =>
354
            Token_Node := New_Node (N_Character_Literal, Token_Ptr);
355
            Set_Char_Literal_Value (Token_Node, UI_From_CC (Character_Code));
356
            Set_Chars (Token_Node, Token_Name);
357
 
358
         when Tok_Identifier =>
359
            Token_Node := New_Node (N_Identifier, Token_Ptr);
360
            Set_Chars (Token_Node, Token_Name);
361
 
362
         when Tok_Real_Literal =>
363
            Token_Node := New_Node (N_Real_Literal, Token_Ptr);
364
            Set_Realval (Token_Node, Real_Literal_Value);
365
            Check_Obsolete_Base_Char;
366
 
367
         when Tok_Integer_Literal =>
368
            Token_Node := New_Node (N_Integer_Literal, Token_Ptr);
369
            Set_Intval (Token_Node, Int_Literal_Value);
370
            Check_Obsolete_Base_Char;
371
 
372
         when Tok_String_Literal =>
373
            Token_Node := New_Node (N_String_Literal, Token_Ptr);
374
            Set_Has_Wide_Character
375
              (Token_Node, Wide_Character_Found);
376
            Set_Has_Wide_Wide_Character
377
              (Token_Node, Wide_Wide_Character_Found);
378
            Set_Strval (Token_Node, String_Literal_Id);
379
 
380
            if Source (Token_Ptr) = '%' then
381
               Check_Obsolescent_Features_Restriction (Token_Ptr);
382
 
383
               if Warn_On_Obsolescent_Feature then
384
                  Error_Msg_SC
385
                    ("use of ""'%"" is an obsolescent feature (RM J.2(4))?");
386
                  Error_Msg_SC ("\use """""" instead?");
387
               end if;
388
            end if;
389
 
390
         when Tok_Operator_Symbol =>
391
            Token_Node := New_Node (N_Operator_Symbol, Token_Ptr);
392
            Set_Chars (Token_Node, Token_Name);
393
            Set_Strval (Token_Node, String_Literal_Id);
394
 
395
         when Tok_Vertical_Bar =>
396
            if Source (Token_Ptr) = '!' then
397
               Check_Obsolescent_Features_Restriction (Token_Ptr);
398
 
399
               if Warn_On_Obsolescent_Feature then
400
                  Error_Msg_SC
401
                    ("use of ""'!"" is an obsolescent feature (RM J.2(2))?");
402
                  Error_Msg_SC ("\use ""'|"" instead?");
403
               end if;
404
            end if;
405
 
406
         when others =>
407
            null;
408
      end case;
409
   end Post_Scan;
410
 
411
   ------------------------------
412
   -- Scan_Reserved_Identifier --
413
   ------------------------------
414
 
415
   procedure Scan_Reserved_Identifier (Force_Msg : Boolean) is
416
      Token_Chars : constant String := Token_Type'Image (Token);
417
 
418
   begin
419
      --  We have in Token_Chars the image of the Token name, i.e. Tok_xxx.
420
      --  This code extracts the xxx and makes an identifier out of it.
421
 
422
      Name_Len := 0;
423
 
424
      for J in 5 .. Token_Chars'Length loop
425
         Name_Len := Name_Len + 1;
426
         Name_Buffer (Name_Len) := Fold_Lower (Token_Chars (J));
427
      end loop;
428
 
429
      Token_Name := Name_Find;
430
 
431
      if not Used_As_Identifier (Token) or else Force_Msg then
432
         Error_Msg_Name_1 := Token_Name;
433
         Error_Msg_SC ("reserved word* cannot be used as identifier!");
434
         Used_As_Identifier (Token) := True;
435
      end if;
436
 
437
      Token := Tok_Identifier;
438
      Token_Node := New_Node (N_Identifier, Token_Ptr);
439
      Set_Chars (Token_Node, Token_Name);
440
   end Scan_Reserved_Identifier;
441
 
442
end Scn;

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