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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [ada/] [scn.adb] - Blame information for rev 826

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1 281 jeremybenn
------------------------------------------------------------------------------
2
--                                                                          --
3
--                         GNAT COMPILER COMPONENTS                         --
4
--                                                                          --
5
--                                  S C N                                   --
6
--                                                                          --
7
--                                 B o d y                                  --
8
--                                                                          --
9
--          Copyright (C) 1992-2009, 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 Output;   use Output;
32
with Restrict; use Restrict;
33
with Rident;   use Rident;
34
with Scans;    use Scans;
35
with Sinfo;    use Sinfo;
36
with Sinput;   use Sinput;
37
with Uintp;    use Uintp;
38
 
39
with GNAT.Byte_Order_Mark; use GNAT.Byte_Order_Mark;
40
 
41
with System.WCh_Con; use System.WCh_Con;
42
 
43
package body Scn is
44
 
45
   use ASCII;
46
 
47
   Obsolescent_Check_Flag : Boolean := True;
48
   --  Obsolescent check activation. Set to False during integrated
49
   --  preprocessing.
50
 
51
   Used_As_Identifier : array (Token_Type) of Boolean;
52
   --  Flags set True if a given keyword is used as an identifier (used to
53
   --  make sure that we only post an error message for incorrect use of a
54
   --  keyword as an identifier once for a given keyword).
55
 
56
   procedure Check_End_Of_Line;
57
   --  Called when end of line encountered. Checks that line is not too long,
58
   --  and that other style checks for the end of line are met.
59
 
60
   function Determine_License return License_Type;
61
   --  Scan header of file and check that it has an appropriate GNAT-style
62
   --  header with a proper license statement. Returns GPL, Unrestricted,
63
   --  or Modified_GPL depending on header. If none of these, returns Unknown.
64
 
65
   procedure Error_Long_Line;
66
   --  Signal error of excessively long line
67
 
68
   -----------------------
69
   -- Check_End_Of_Line --
70
   -----------------------
71
 
72
   procedure Check_End_Of_Line is
73
      Len : constant Int := Int (Scan_Ptr) - Int (Current_Line_Start);
74
   begin
75
      if Style_Check then
76
         Style.Check_Line_Terminator (Len);
77
      elsif Len > Max_Line_Length then
78
         Error_Long_Line;
79
      end if;
80
   end Check_End_Of_Line;
81
 
82
   -----------------------
83
   -- Determine_License --
84
   -----------------------
85
 
86
   function Determine_License return License_Type is
87
      GPL_Found : Boolean := False;
88
      Result    : License_Type;
89
 
90
      function Contains (S : String) return Boolean;
91
      --  See if current comment contains successive non-blank characters
92
      --  matching the contents of S. If so leave Scan_Ptr unchanged and
93
      --  return True, otherwise leave Scan_Ptr unchanged and return False.
94
 
95
      procedure Skip_EOL;
96
      --  Skip to line terminator character
97
 
98
      --------------
99
      -- Contains --
100
      --------------
101
 
102
      function Contains (S : String) return Boolean is
103
         CP : Natural;
104
         SP : Source_Ptr;
105
         SS : Source_Ptr;
106
 
107
      begin
108
         --  Loop to check characters. This loop is terminated by end of
109
         --  line, and also we need to check for the EOF case, to take
110
         --  care of files containing only comments.
111
 
112
         SP := Scan_Ptr;
113
         while Source (SP) /= CR and then
114
               Source (SP) /= LF and then
115
               Source (SP) /= EOF
116
         loop
117
            if Source (SP) = S (S'First) then
118
               SS := SP;
119
               CP := S'First;
120
 
121
               loop
122
                  SS := SS + 1;
123
                  CP := CP + 1;
124
 
125
                  if CP > S'Last then
126
                     return True;
127
                  end if;
128
 
129
                  while Source (SS) = ' ' loop
130
                     SS := SS + 1;
131
                  end loop;
132
 
133
                  exit when Source (SS) /= S (CP);
134
               end loop;
135
            end if;
136
 
137
            SP := SP + 1;
138
         end loop;
139
 
140
         return False;
141
      end Contains;
142
 
143
      --------------
144
      -- Skip_EOL --
145
      --------------
146
 
147
      procedure Skip_EOL is
148
      begin
149
         while Source (Scan_Ptr) /= CR
150
           and then Source (Scan_Ptr) /= LF
151
           and then Source (Scan_Ptr) /= EOF
152
         loop
153
            Scan_Ptr := Scan_Ptr + 1;
154
         end loop;
155
      end Skip_EOL;
156
 
157
   --  Start of processing for Determine_License
158
 
159
   begin
160
      loop
161
         if Source (Scan_Ptr) /= '-'
162
           or else Source (Scan_Ptr + 1) /= '-'
163
         then
164
            if GPL_Found then
165
               Result := GPL;
166
               exit;
167
            else
168
               Result := Unknown;
169
               exit;
170
            end if;
171
 
172
         elsif Contains ("Asaspecialexception") then
173
            if GPL_Found then
174
               Result := Modified_GPL;
175
               exit;
176
            end if;
177
 
178
         elsif Contains ("GNUGeneralPublicLicense") then
179
            GPL_Found := True;
180
 
181
         elsif
182
             Contains
183
               ("ThisspecificationisadaptedfromtheAdaSemanticInterface")
184
           or else
185
             Contains
186
              ("ThisspecificationisderivedfromtheAdaReferenceManual")
187
         then
188
            Result := Unrestricted;
189
            exit;
190
         end if;
191
 
192
         Skip_EOL;
193
 
194
         Check_End_Of_Line;
195
 
196
         if Source (Scan_Ptr) /= EOF then
197
 
198
            --  We have to take into account a degenerate case when the source
199
            --  file contains only comments and no Ada code.
200
 
201
            declare
202
               Physical : Boolean;
203
 
204
            begin
205
               Skip_Line_Terminators (Scan_Ptr, Physical);
206
 
207
               --  If we are at start of physical line, update scan pointers
208
               --  to reflect the start of the new line.
209
 
210
               if Physical then
211
                  Current_Line_Start       := Scan_Ptr;
212
                  Start_Column             := Scanner.Set_Start_Column;
213
                  First_Non_Blank_Location := Scan_Ptr;
214
               end if;
215
            end;
216
         end if;
217
      end loop;
218
 
219
      return Result;
220
   end Determine_License;
221
 
222
   ----------------------------
223
   -- Determine_Token_Casing --
224
   ----------------------------
225
 
226
   function Determine_Token_Casing return Casing_Type is
227
   begin
228
      return Scanner.Determine_Token_Casing;
229
   end Determine_Token_Casing;
230
 
231
   ---------------------
232
   -- Error_Long_Line --
233
   ---------------------
234
 
235
   procedure Error_Long_Line is
236
   begin
237
      Error_Msg
238
        ("this line is too long",
239
         Current_Line_Start + Source_Ptr (Max_Line_Length));
240
   end Error_Long_Line;
241
 
242
   ------------------------
243
   -- Initialize_Scanner --
244
   ------------------------
245
 
246
   procedure Initialize_Scanner
247
     (Unit  : Unit_Number_Type;
248
      Index : Source_File_Index)
249
   is
250
      GNAT_Hedr : constant Text_Buffer (1 .. 78) := (others => '-');
251
 
252
   begin
253
      Scanner.Initialize_Scanner (Index);
254
 
255
      if Index /= Internal_Source_File then
256
         Set_Unit (Index, Unit);
257
      end if;
258
 
259
      Current_Source_Unit := Unit;
260
 
261
      --  Set default for Comes_From_Source (except if we are going to process
262
      --  an artificial string internally created within the compiler and
263
      --  placed into internal source duffer). All nodes built now until we
264
      --  reenter the analyzer will have Comes_From_Source set to True
265
 
266
      if Index /= Internal_Source_File then
267
         Set_Comes_From_Source_Default (True);
268
      end if;
269
 
270
      --  Check license if GNAT type header possibly present
271
 
272
      if Source_Last (Index) - Scan_Ptr > 80
273
        and then Source (Scan_Ptr .. Scan_Ptr + 77) = GNAT_Hedr
274
      then
275
         Set_License (Current_Source_File, Determine_License);
276
      end if;
277
 
278
      --  Check for BOM
279
 
280
      declare
281
         BOM : BOM_Kind;
282
         Len : Natural;
283
         Tst : String (1 .. 5);
284
 
285
      begin
286
         for J in 1 .. 5 loop
287
            Tst (J) := Source (Scan_Ptr + Source_Ptr (J) - 1);
288
         end loop;
289
 
290
         Read_BOM (Tst, Len, BOM, False);
291
 
292
         case BOM is
293
            when UTF8_All =>
294
               Scan_Ptr := Scan_Ptr + Source_Ptr (Len);
295
               Wide_Character_Encoding_Method := WCEM_UTF8;
296
               Upper_Half_Encoding := True;
297
 
298
            when UTF16_LE | UTF16_BE =>
299
               Set_Standard_Error;
300
               Write_Line ("UTF-16 encoding format not recognized");
301
               Set_Standard_Output;
302
               raise Unrecoverable_Error;
303
 
304
            when UTF32_LE | UTF32_BE =>
305
               Set_Standard_Error;
306
               Write_Line ("UTF-32 encoding format not recognized");
307
               Set_Standard_Output;
308
               raise Unrecoverable_Error;
309
 
310
            when Unknown =>
311
               null;
312
 
313
            when others =>
314
               raise Program_Error;
315
         end case;
316
      end;
317
 
318
      --  Because of the License stuff above, Scng.Initialize_Scanner cannot
319
      --  call Scan. Scan initial token (note this initializes Prev_Token,
320
      --  Prev_Token_Ptr).
321
 
322
      --  There are two reasons not to do the Scan step in case if we
323
      --  initialize the scanner for the internal source buffer:
324
 
325
      --  - The artificial string may not be created by the compiler in this
326
      --    buffer when we call Initialize_Scanner
327
 
328
      --  - For these artificial strings a special way of scanning is used, so
329
      --    the standard step of the scanner may just break the algorithm of
330
      --    processing these strings.
331
 
332
      if Index /= Internal_Source_File then
333
         Scan;
334
      end if;
335
 
336
      --  Clear flags for reserved words used as identifiers
337
 
338
      for J in Token_Type loop
339
         Used_As_Identifier (J) := False;
340
      end loop;
341
   end Initialize_Scanner;
342
 
343
   -----------------------
344
   -- Obsolescent_Check --
345
   -----------------------
346
 
347
   procedure Obsolescent_Check (S : Source_Ptr) is
348
   begin
349
      if Obsolescent_Check_Flag then
350
         --  This is a pain in the neck case, since we normally need a node to
351
         --  call Check_Restrictions, and all we have is a source pointer. The
352
         --  easiest thing is to construct a dummy node. A bit kludgy, but this
353
         --  is a marginal case. It's not worth trying to do things more
354
         --  cleanly.
355
 
356
         Check_Restriction (No_Obsolescent_Features, New_Node (N_Empty, S));
357
      end if;
358
   end Obsolescent_Check;
359
 
360
   ---------------
361
   -- Post_Scan --
362
   ---------------
363
 
364
   procedure Post_Scan is
365
   begin
366
      case Token is
367
         when Tok_Char_Literal =>
368
            Token_Node := New_Node (N_Character_Literal, Token_Ptr);
369
            Set_Char_Literal_Value (Token_Node, UI_From_CC (Character_Code));
370
            Set_Chars (Token_Node, Token_Name);
371
 
372
         when Tok_Identifier =>
373
            Token_Node := New_Node (N_Identifier, Token_Ptr);
374
            Set_Chars (Token_Node, Token_Name);
375
 
376
         when Tok_Real_Literal =>
377
            Token_Node := New_Node (N_Real_Literal, Token_Ptr);
378
            Set_Realval (Token_Node, Real_Literal_Value);
379
 
380
         when Tok_Integer_Literal =>
381
            Token_Node := New_Node (N_Integer_Literal, Token_Ptr);
382
            Set_Intval (Token_Node, Int_Literal_Value);
383
 
384
         when Tok_String_Literal =>
385
            Token_Node := New_Node (N_String_Literal, Token_Ptr);
386
            Set_Has_Wide_Character
387
              (Token_Node, Wide_Character_Found);
388
            Set_Has_Wide_Wide_Character
389
              (Token_Node, Wide_Wide_Character_Found);
390
            Set_Strval (Token_Node, String_Literal_Id);
391
 
392
         when Tok_Operator_Symbol =>
393
            Token_Node := New_Node (N_Operator_Symbol, Token_Ptr);
394
            Set_Chars (Token_Node, Token_Name);
395
            Set_Strval (Token_Node, String_Literal_Id);
396
 
397
         when others =>
398
            null;
399
      end case;
400
   end Post_Scan;
401
 
402
   ------------------------------
403
   -- Scan_Reserved_Identifier --
404
   ------------------------------
405
 
406
   procedure Scan_Reserved_Identifier (Force_Msg : Boolean) is
407
      Token_Chars : constant String := Token_Type'Image (Token);
408
 
409
   begin
410
      --  We have in Token_Chars the image of the Token name, i.e. Tok_xxx.
411
      --  This code extracts the xxx and makes an identifier out of it.
412
 
413
      Name_Len := 0;
414
 
415
      for J in 5 .. Token_Chars'Length loop
416
         Name_Len := Name_Len + 1;
417
         Name_Buffer (Name_Len) := Fold_Lower (Token_Chars (J));
418
      end loop;
419
 
420
      Token_Name := Name_Find;
421
 
422
      if not Used_As_Identifier (Token) or else Force_Msg then
423
         Error_Msg_Name_1 := Token_Name;
424
         Error_Msg_SC ("reserved word* cannot be used as identifier!");
425
         Used_As_Identifier (Token) := True;
426
      end if;
427
 
428
      Token := Tok_Identifier;
429
      Token_Node := New_Node (N_Identifier, Token_Ptr);
430
      Set_Chars (Token_Node, Token_Name);
431
   end Scan_Reserved_Identifier;
432
 
433
   ---------------------------
434
   -- Set_Obsolescent_Check --
435
   ---------------------------
436
 
437
   procedure Set_Obsolescent_Check (Value : Boolean) is
438
   begin
439
      Obsolescent_Check_Flag := Value;
440
   end Set_Obsolescent_Check;
441
 
442
end Scn;

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