1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                             A L I . U T I L                              --
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
26with Debug;   use Debug;
27with Binderr; use Binderr;
28with Opt;     use Opt;
29with Output;  use Output;
30with Osint;   use Osint;
31with Scans;   use Scans;
32with Scng;
33with Sinput.C;
34with Snames;  use Snames;
35with Stringt;
36with Styleg;
37
38package body ALI.Util is
39
40   --  Empty procedures needed to instantiate Scng. Error procedures are
41   --  empty, because we don't want to report any errors when computing
42   --  a source checksum.
43
44   procedure Post_Scan;
45
46   procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr);
47
48   procedure Error_Msg_S (Msg : String);
49
50   procedure Error_Msg_SC (Msg : String);
51
52   procedure Error_Msg_SP (Msg : String);
53
54   --  Instantiation of Styleg, needed to instantiate Scng
55
56   package Style is new Styleg
57     (Error_Msg, Error_Msg_S, Error_Msg_SC, Error_Msg_SP);
58
59   --  A Scanner is needed to get checksum of a source (procedure
60   --  Get_File_Checksum).
61
62   package Scanner is new Scng
63     (Post_Scan, Error_Msg, Error_Msg_S, Error_Msg_SC, Error_Msg_SP, Style);
64
65   type Header_Num is range 0 .. 1_000;
66
67   function Hash (F : File_Name_Type) return Header_Num;
68   --  Function used to compute hash of ALI file name
69
70   package Interfaces is new Simple_HTable (
71     Header_Num => Header_Num,
72     Element    => Boolean,
73     No_Element => False,
74     Key        => File_Name_Type,
75     Hash       => Hash,
76     Equal      => "=");
77
78   ---------------------
79   -- Checksums_Match --
80   ---------------------
81
82   function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean is
83   begin
84      return Checksum1 = Checksum2 and then Checksum1 /= Checksum_Error;
85   end Checksums_Match;
86
87   ---------------
88   -- Error_Msg --
89   ---------------
90
91   procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr) is
92      pragma Warnings (Off, Msg);
93      pragma Warnings (Off, Flag_Location);
94   begin
95      null;
96   end Error_Msg;
97
98   -----------------
99   -- Error_Msg_S --
100   -----------------
101
102   procedure Error_Msg_S (Msg : String) is
103      pragma Warnings (Off, Msg);
104   begin
105      null;
106   end Error_Msg_S;
107
108   ------------------
109   -- Error_Msg_SC --
110   ------------------
111
112   procedure Error_Msg_SC (Msg : String) is
113      pragma Warnings (Off, Msg);
114   begin
115      null;
116   end Error_Msg_SC;
117
118   ------------------
119   -- Error_Msg_SP --
120   ------------------
121
122   procedure Error_Msg_SP (Msg : String) is
123      pragma Warnings (Off, Msg);
124   begin
125      null;
126   end Error_Msg_SP;
127
128   -----------------------
129   -- Get_File_Checksum --
130   -----------------------
131
132   function Get_File_Checksum (Fname : File_Name_Type) return Word is
133      Full_Name    : File_Name_Type;
134      Source_Index : Source_File_Index;
135
136   begin
137      Full_Name := Find_File (Fname, Osint.Source);
138
139      --  If we cannot find the file, then return an impossible checksum,
140      --  impossible because checksums have the high order bit zero, so
141      --  that checksums do not match.
142
143      if Full_Name = No_File then
144         return Checksum_Error;
145      end if;
146
147      Source_Index := Sinput.C.Load_File (Get_Name_String (Full_Name));
148
149      if Source_Index = No_Source_File then
150         return Checksum_Error;
151      end if;
152
153      Scanner.Initialize_Scanner (Source_Index);
154
155      --  Make sure that the project language reserved words are not
156      --  recognized as reserved words, but as identifiers. The byte info for
157      --  those names have been set if we are in gnatmake.
158
159      Set_Name_Table_Byte (Name_Project,          0);
160      Set_Name_Table_Byte (Name_Extends,          0);
161      Set_Name_Table_Byte (Name_External,         0);
162      Set_Name_Table_Byte (Name_External_As_List, 0);
163
164      --  Scan the complete file to compute its checksum
165
166      loop
167         Scanner.Scan;
168         exit when Token = Tok_EOF;
169      end loop;
170
171      return Scans.Checksum;
172   end Get_File_Checksum;
173
174   ----------
175   -- Hash --
176   ----------
177
178   function Hash (F : File_Name_Type) return Header_Num is
179   begin
180      return Header_Num (Int (F) rem Header_Num'Range_Length);
181   end Hash;
182
183   ---------------------------
184   -- Initialize_ALI_Source --
185   ---------------------------
186
187   procedure Initialize_ALI_Source is
188   begin
189      --  When (re)initializing ALI data structures the ALI user expects to
190      --  get a fresh set of data structures. Thus we first need to erase the
191      --  marks put in the name table by the previous set of ALI routine calls.
192      --  This loop is empty and harmless the first time in.
193
194      for J in Source.First .. Source.Last loop
195         Set_Name_Table_Info (Source.Table (J).Sfile, 0);
196         Source.Table (J).Source_Found := False;
197      end loop;
198
199      Source.Init;
200      Interfaces.Reset;
201   end Initialize_ALI_Source;
202
203   ---------------
204   -- Post_Scan --
205   ---------------
206
207   procedure Post_Scan is
208   begin
209      null;
210   end Post_Scan;
211
212   ----------------------
213   -- Read_Withed_ALIs --
214   ----------------------
215
216   procedure Read_Withed_ALIs
217     (Id            : ALI_Id;
218      Ignore_Errors : Boolean := False)
219   is
220      Afile  : File_Name_Type;
221      Text   : Text_Buffer_Ptr;
222      Idread : ALI_Id;
223
224   begin
225      --  Process all dependent units
226
227      for U in ALIs.Table (Id).First_Unit .. ALIs.Table (Id).Last_Unit loop
228         for
229           W in Units.Table (U).First_With .. Units.Table (U).Last_With
230         loop
231            Afile := Withs.Table (W).Afile;
232
233            --  Only process if not a generic (Afile /= No_File) and if
234            --  file has not been processed already.
235
236            if Afile /= No_File
237              and then Get_Name_Table_Info (Afile) = 0
238            then
239               Text := Read_Library_Info (Afile);
240
241               --  Unless Ignore_Errors is true, return with an error if source
242               --  cannot be found. We used to skip this check when we did not
243               --  compile library generics separately, but we now always do,
244               --  so there is no special case here anymore.
245
246               if Text = null then
247
248                  if not Ignore_Errors then
249                     Error_Msg_File_1 := Afile;
250                     Error_Msg_File_2 := Withs.Table (W).Sfile;
251                     Error_Msg ("{ not found, { must be compiled");
252                     Set_Name_Table_Info (Afile, Int (No_Unit_Id));
253                     return;
254                  end if;
255
256               else
257                  --  Enter in ALIs table
258
259                  Idread :=
260                    Scan_ALI
261                      (F         => Afile,
262                       T         => Text,
263                       Ignore_ED => False,
264                       Err       => False);
265
266                  Free (Text);
267
268                  if ALIs.Table (Idread).Compile_Errors
269                    and then not Ignore_Errors
270                  then
271                     Error_Msg_File_1 := Withs.Table (W).Sfile;
272                     Error_Msg ("{ had errors, must be fixed, and recompiled");
273                     Set_Name_Table_Info (Afile, Int (No_Unit_Id));
274
275                  elsif ALIs.Table (Idread).No_Object
276                    and then not Ignore_Errors
277                  then
278                     Error_Msg_File_1 := Withs.Table (W).Sfile;
279                     Error_Msg ("{ must be recompiled");
280                     Set_Name_Table_Info (Afile, Int (No_Unit_Id));
281                  end if;
282
283                  --  If the Unit is an Interface to a Stand-Alone Library,
284                  --  set the Interface flag in the Withs table, so that its
285                  --  dependant are not considered for elaboration order.
286
287                  if ALIs.Table (Idread).SAL_Interface then
288                     Withs.Table (W).SAL_Interface := True;
289                     Interface_Library_Unit := True;
290
291                     --  Set the entry in the Interfaces hash table, so that
292                     --  other units that import this unit will set the flag
293                     --  in their entry in the Withs table.
294
295                     Interfaces.Set (Afile, True);
296
297                  else
298                     --  Otherwise, recurse to get new dependents
299
300                     Read_Withed_ALIs (Idread);
301                  end if;
302               end if;
303
304            --  If the ALI file has already been processed and is an interface,
305            --  set the flag in the entry of the Withs table.
306
307            elsif Interface_Library_Unit and then Interfaces.Get (Afile) then
308               Withs.Table (W).SAL_Interface := True;
309            end if;
310         end loop;
311      end loop;
312   end Read_Withed_ALIs;
313
314   ----------------------
315   -- Set_Source_Table --
316   ----------------------
317
318   procedure Set_Source_Table (A : ALI_Id) is
319      F     : File_Name_Type;
320      S     : Source_Id;
321      Stamp : Time_Stamp_Type;
322
323   begin
324      Sdep_Loop : for D in
325        ALIs.Table (A).First_Sdep .. ALIs.Table (A).Last_Sdep
326      loop
327         F := Sdep.Table (D).Sfile;
328
329         if F /= No_File then
330
331            --  If this is the first time we are seeing this source file,
332            --  then make a new entry in the source table.
333
334            if Get_Name_Table_Info (F) = 0 then
335               Source.Increment_Last;
336               S := Source.Last;
337               Set_Name_Table_Info (F, Int (S));
338               Source.Table (S).Sfile := F;
339               Source.Table (S).All_Timestamps_Match := True;
340
341               --  Initialize checksum fields
342
343               Source.Table (S).Checksum := Sdep.Table (D).Checksum;
344               Source.Table (S).All_Checksums_Match := True;
345
346               --  In check source files mode, try to get time stamp from file
347
348               if Opt.Check_Source_Files then
349                  Stamp := Source_File_Stamp (F);
350
351                  --  If we got the stamp, then set the stamp in the source
352                  --  table entry and mark it as set from the source so that
353                  --  it does not get subsequently changed.
354
355                  if Stamp (Stamp'First) /= ' ' then
356                     Source.Table (S).Stamp := Stamp;
357                     Source.Table (S).Source_Found := True;
358
359                  --  If we could not find the file, then the stamp is set
360                  --  from the dependency table entry (to be possibly reset
361                  --  if we find a later stamp in subsequent processing)
362
363                  else
364                     Source.Table (S).Stamp := Sdep.Table (D).Stamp;
365                     Source.Table (S).Source_Found := False;
366
367                     --  In All_Sources mode, flag error of file not found
368
369                     if Opt.All_Sources then
370                        Error_Msg_File_1 := F;
371                        Error_Msg ("cannot locate {");
372                     end if;
373                  end if;
374
375               --  First time for this source file, but Check_Source_Files
376               --  is off, so simply initialize the stamp from the Sdep entry
377
378               else
379                  Source.Table (S).Source_Found := False;
380                  Source.Table (S).Stamp := Sdep.Table (D).Stamp;
381               end if;
382
383            --  Here if this is not the first time for this source file,
384            --  so that the source table entry is already constructed.
385
386            else
387               S := Source_Id (Get_Name_Table_Info (F));
388
389               --  Update checksum flag
390
391               if not Checksums_Match
392                        (Sdep.Table (D).Checksum, Source.Table (S).Checksum)
393               then
394                  Source.Table (S).All_Checksums_Match := False;
395               end if;
396
397               --  Check for time stamp mismatch
398
399               if Sdep.Table (D).Stamp /= Source.Table (S).Stamp then
400                  Source.Table (S).All_Timestamps_Match := False;
401
402                  --  When we have a time stamp mismatch, we go look for the
403                  --  source file even if Check_Source_Files is false, since
404                  --  if we find it, then we can use it to resolve which of the
405                  --  two timestamps in the ALI files is likely to be correct.
406
407                  if not Check_Source_Files then
408                     Stamp := Source_File_Stamp (F);
409
410                     if Stamp (Stamp'First) /= ' ' then
411                        Source.Table (S).Stamp := Stamp;
412                        Source.Table (S).Source_Found := True;
413                     end if;
414                  end if;
415
416                  --  If the stamp in the source table entry was set from the
417                  --  source file, then we do not change it (the stamp in the
418                  --  source file is always taken as the "right" one).
419
420                  if Source.Table (S).Source_Found then
421                     null;
422
423                  --  Otherwise, we have no source file available, so we guess
424                  --  that the later of the two timestamps is the right one.
425                  --  Note that this guess only affects which error messages
426                  --  are issued later on, not correct functionality.
427
428                  else
429                     if Sdep.Table (D).Stamp > Source.Table (S).Stamp then
430                        Source.Table (S).Stamp := Sdep.Table (D).Stamp;
431                     end if;
432                  end if;
433               end if;
434            end if;
435
436            --  Set the checksum value in the source table
437
438            S := Source_Id (Get_Name_Table_Info (F));
439            Source.Table (S).Checksum := Sdep.Table (D).Checksum;
440         end if;
441
442      end loop Sdep_Loop;
443   end Set_Source_Table;
444
445   ----------------------
446   -- Set_Source_Table --
447   ----------------------
448
449   procedure Set_Source_Table is
450   begin
451      for A in ALIs.First .. ALIs.Last loop
452         Set_Source_Table (A);
453      end loop;
454   end Set_Source_Table;
455
456   -------------------------
457   -- Time_Stamp_Mismatch --
458   -------------------------
459
460   function Time_Stamp_Mismatch
461     (A         : ALI_Id;
462      Read_Only : Boolean := False) return File_Name_Type
463   is
464      Src : Source_Id;
465      --  Source file Id for the current Sdep entry
466
467   begin
468      for D in ALIs.Table (A).First_Sdep .. ALIs.Table (A).Last_Sdep loop
469         Src := Source_Id (Get_Name_Table_Info (Sdep.Table (D).Sfile));
470
471         if Opt.Minimal_Recompilation
472           and then Sdep.Table (D).Stamp /= Source.Table (Src).Stamp
473         then
474            --  If minimal recompilation is in action, replace the stamp
475            --  of the source file in the table if checksums match.
476
477            --  ??? It is probably worth updating the ALI file with a new
478            --  field to avoid recomputing it each time. In any case we ensure
479            --  that we don't gobble up string table space by doing a mark
480            --  release around this computation.
481
482            Stringt.Mark;
483
484            if Checksums_Match
485                 (Get_File_Checksum (Sdep.Table (D).Sfile),
486                  Source.Table (Src).Checksum)
487            then
488               if Verbose_Mode then
489                  Write_Str ("   ");
490                  Write_Str (Get_Name_String (Sdep.Table (D).Sfile));
491                  Write_Str (": up to date, different timestamps " &
492                             "but same checksum");
493                  Write_Eol;
494               end if;
495
496               Sdep.Table (D).Stamp := Source.Table (Src).Stamp;
497            end if;
498
499            Stringt.Release;
500         end if;
501
502         if (not Read_Only) or else Source.Table (Src).Source_Found then
503            if not Source.Table (Src).Source_Found
504              or else Sdep.Table (D).Stamp /= Source.Table (Src).Stamp
505            then
506               --  If -dt debug flag set, output time stamp found/expected
507
508               if Source.Table (Src).Source_Found and then Debug_Flag_T then
509                  Write_Str ("Source: """);
510                  Get_Name_String (Sdep.Table (D).Sfile);
511                  Write_Str (Name_Buffer (1 .. Name_Len));
512                  Write_Line ("""");
513
514                  Write_Str ("   time stamp expected: ");
515                  Write_Line (String (Sdep.Table (D).Stamp));
516
517                  Write_Str ("      time stamp found: ");
518                  Write_Line (String (Source.Table (Src).Stamp));
519               end if;
520
521               --  Return the source file
522
523               return Source.Table (Src).Sfile;
524            end if;
525         end if;
526      end loop;
527
528      return No_File;
529   end Time_Stamp_Mismatch;
530
531end ALI.Util;
532