1 /* Implicit rule searching for GNU Make.
2 Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
5 This file is part of GNU Make.
7 GNU Make is free software; you can redistribute it and/or modify it under the
8 terms of the GNU General Public License as published by the Free Software
9 Foundation; either version 3 of the License, or (at your option) any later
12 GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
14 A PARTICULAR PURPOSE. See the GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License along with
17 this program. If not, see <http://www.gnu.org/licenses/>. */
25 #include "job.h" /* struct child, used inside commands.h */
26 #include "commands.h" /* set_file_variables */
28 static int pattern_search (struct file
*file
, int archive
,
29 unsigned int depth
, unsigned int recursions
);
31 /* For a FILE which has no commands specified, try to figure out some
32 from the implicit pattern rules.
33 Returns 1 if a suitable implicit rule was found,
34 after modifying FILE to contain the appropriate commands and deps,
35 or returns 0 if no implicit rule was found. */
38 try_implicit_rule (struct file
*file
, unsigned int depth
)
40 DBF (DB_IMPLICIT
, _("Looking for an implicit rule for `%s'.\n"));
42 /* The order of these searches was previously reversed. My logic now is
43 that since the non-archive search uses more information in the target
44 (the archive search omits the archive name), it is more specific and
47 if (pattern_search (file
, 0, depth
, 0))
51 /* If this is an archive member reference, use just the
52 archive member name to search for implicit rules. */
53 if (ar_name (file
->name
))
56 _("Looking for archive-member implicit rule for `%s'.\n"));
57 if (pattern_search (file
, 1, depth
, 0))
66 /* Scans the BUFFER for the next word with whitespace as a separator.
67 Returns the pointer to the beginning of the word. LENGTH hold the
68 length of the word. */
71 get_next_word (const char *buffer
, unsigned int *length
)
73 const char *p
= buffer
, *beg
;
76 /* Skip any leading whitespace. */
77 while (isblank ((unsigned char)*p
))
87 /* We already found the first value of "c", above. */
105 /* This is a variable reference, so read it to the matching
113 /* This is a single-letter variable reference. */
116 for (count
= 0; *p
!= '\0'; ++p
)
120 else if (*p
== closeparen
&& --count
< 0)
147 /* This structure stores information about the expanded prerequisites for a
148 pattern rule. NAME is always set, to the strcache'd name of the prereq.
149 FILE and PATTERN will be set for intermediate files only. IGNORE_MTIME is
150 copied from the prerequisite we expanded.
157 unsigned int ignore_mtime
: 1;
160 /* Search the pattern rules for a rule with an existing dependency to make
161 FILE. If a rule is found, the appropriate commands and deps are put in FILE
162 and 1 is returned. If not, 0 is returned.
164 If ARCHIVE is nonzero, FILE->name is of the form "LIB(MEMBER)". A rule for
165 "(MEMBER)" will be searched for, and "(MEMBER)" will not be chopped up into
166 directory and filename parts.
168 If an intermediate file is found by pattern search, the intermediate file
169 is set up as a target by the recursive call and is also made a dependency
172 DEPTH is used for debugging messages. */
175 pattern_search (struct file
*file
, int archive
,
176 unsigned int depth
, unsigned int recursions
)
178 /* Filename we are searching for a rule for. */
179 const char *filename
= archive
? strchr (file
->name
, '(') : file
->name
;
181 /* Length of FILENAME. */
182 unsigned int namelen
= strlen (filename
);
184 /* The last slash in FILENAME (or nil if there is none). */
187 /* This is a file-object used as an argument in
188 recursive calls. It never contains any data
189 except during a recursive call. */
190 struct file
*int_file
= 0;
192 /* List of dependencies found recursively. */
193 struct patdeps
*deplist
194 = xmalloc (max_pattern_deps
* sizeof (struct patdeps
));
195 struct patdeps
*pat
= deplist
;
197 /* All the prerequisites actually found for a rule, after expansion. */
200 /* Names of possible dependencies are constructed in this buffer. */
201 char *depname
= alloca (namelen
+ max_pattern_dep_length
);
203 /* The start and length of the stem of FILENAME for the current rule. */
204 const char *stem
= 0;
205 unsigned int stemlen
= 0;
206 unsigned int fullstemlen
= 0;
208 /* Buffer in which we store all the rules that are possibly applicable. */
209 struct rule
**tryrules
= xmalloc (num_pattern_rules
* max_pattern_targets
210 * sizeof (struct rule
*));
212 /* Number of valid elements in TRYRULES. */
215 /* The numbers of the rule targets of each rule
216 in TRYRULES that matched the target file. */
217 unsigned int *matches
= alloca (num_pattern_rules
* sizeof (unsigned int));
219 /* Each element is nonzero if LASTSLASH was used in
220 matching the corresponding element of TRYRULES. */
221 char *checked_lastslash
= alloca (num_pattern_rules
* sizeof (char));
223 /* The index in TRYRULES of the rule we found. */
224 unsigned int foundrule
;
226 /* Nonzero if should consider intermediate files as dependencies. */
229 /* Nonzero if we have matched a pattern-rule target
230 that is not just `%'. */
231 int specific_rule_matched
= 0;
233 struct nameseq ns_simple
;
235 unsigned int ri
; /* uninit checks OK */
238 char *pathdir
= NULL
;
239 unsigned long pathlen
;
241 PATH_VAR (stem_str
); /* @@ Need to get rid of stem, stemlen, etc. */
244 if (archive
|| ar_name (filename
))
249 /* Set LASTSLASH to point at the last slash in FILENAME
250 but not counting any slash at the end. (foo/bar/ counts as
251 bar/ in directory foo/, not empty in directory foo/bar/.) */
253 lastslash
= strrchr (filename
, ']');
255 lastslash
= strrchr (filename
, ':');
257 lastslash
= strrchr (filename
, '/');
258 #ifdef HAVE_DOS_PATHS
259 /* Handle backslashes (possibly mixed with forward slashes)
260 and the case of "d:file". */
262 char *bslash
= strrchr (filename
, '\\');
263 if (lastslash
== 0 || bslash
> lastslash
)
265 if (lastslash
== 0 && filename
[0] && filename
[1] == ':')
266 lastslash
= filename
+ 1;
270 if (lastslash
!= 0 && lastslash
[1] == '\0')
274 pathlen
= lastslash
- filename
+ 1;
278 /* First see which pattern rules match this target and may be considered.
279 Put them in TRYRULES. */
282 for (rule
= pattern_rules
; rule
!= 0; rule
= rule
->next
)
286 /* If the pattern rule has deps but no commands, ignore it.
287 Users cancel built-in rules by redefining them without commands. */
288 if (rule
->deps
!= 0 && rule
->cmds
== 0)
291 /* If this rule is in use by a parent pattern_search,
292 don't use it here. */
295 DBS (DB_IMPLICIT
, (_("Avoiding implicit rule recursion.\n")));
299 for (ti
= 0; ti
< rule
->num
; ++ti
)
301 const char *target
= rule
->targets
[ti
];
302 const char *suffix
= rule
->suffixes
[ti
];
305 /* Rules that can match any filename and are not terminal
306 are ignored if we're recursing, so that they cannot be
307 intermediate files. */
308 if (recursions
> 0 && target
[1] == '\0' && !rule
->terminal
)
311 if (rule
->lens
[ti
] > namelen
)
312 /* It can't possibly match. */
315 /* From the lengths of the filename and the pattern parts,
316 find the stem: the part of the filename that matches the %. */
317 stem
= filename
+ (suffix
- target
- 1);
318 stemlen
= namelen
- rule
->lens
[ti
] + 1;
320 /* Set CHECK_LASTSLASH if FILENAME contains a directory
321 prefix and the target pattern does not contain a slash. */
327 check_lastslash
= (strchr (target
, ']') == 0
328 && strchr (target
, ':') == 0);
330 check_lastslash
= strchr (target
, '/') == 0;
331 #ifdef HAVE_DOS_PATHS
332 /* Didn't find it yet: check for DOS-type directories. */
335 char *b
= strchr (target
, '\\');
336 check_lastslash
= !(b
|| (target
[0] && target
[1] == ':'));
343 /* If so, don't include the directory prefix in STEM here. */
344 if (pathlen
> stemlen
)
350 /* Check that the rule pattern matches the text before the stem. */
353 if (stem
> (lastslash
+ 1)
354 && !strneq (target
, lastslash
+ 1, stem
- lastslash
- 1))
357 else if (stem
> filename
358 && !strneq (target
, filename
, stem
- filename
))
361 /* Check that the rule pattern matches the text after the stem.
362 We could test simply use streq, but this way we compare the
363 first two characters immediately. This saves time in the very
364 common case where the first character matches because it is a
366 if (*suffix
!= stem
[stemlen
]
367 || (*suffix
!= '\0' && !streq (&suffix
[1], &stem
[stemlen
+ 1])))
370 /* Record if we match a rule that not all filenames will match. */
371 if (target
[1] != '\0')
372 specific_rule_matched
= 1;
374 /* A rule with no dependencies and no commands exists solely to set
375 specific_rule_matched when it matches. Don't try to use it. */
376 if (rule
->deps
== 0 && rule
->cmds
== 0)
379 /* Record this rule in TRYRULES and the index of the matching
380 target in MATCHES. If several targets of the same rule match,
381 that rule will be in TRYRULES more than once. */
382 tryrules
[nrules
] = rule
;
383 matches
[nrules
] = ti
;
384 checked_lastslash
[nrules
] = check_lastslash
;
389 /* If we have found a matching rule that won't match all filenames,
390 retroactively reject any non-"terminal" rules that do always match. */
391 if (specific_rule_matched
)
392 for (ri
= 0; ri
< nrules
; ++ri
)
393 if (!tryrules
[ri
]->terminal
)
396 for (j
= 0; j
< tryrules
[ri
]->num
; ++j
)
397 if (tryrules
[ri
]->targets
[j
][1] == '\0')
404 /* We are going to do second expansion so initialize file variables
406 initialize_file_variables (file
, 0);
408 /* Try each rule once without intermediate files, then once with them. */
409 for (intermed_ok
= 0; intermed_ok
< 2; ++intermed_ok
)
413 /* Try each pattern rule till we find one that applies. If it does,
414 expand its dependencies (as substituted) and chain them in DEPS. */
415 for (ri
= 0; ri
< nrules
; ri
++)
418 unsigned int failed
= 0;
420 int file_variables_set
= 0;
421 unsigned int deps_found
= 0;
422 /* NPTR points to the part of the prereq we haven't processed. */
423 const char *nptr
= 0;
427 /* RULE is nil when we discover that a rule, already placed in
428 TRYRULES, should not be applied. */
432 /* Reject any terminal rules if we're looking to make intermediate
434 if (intermed_ok
&& rule
->terminal
)
437 /* From the lengths of the filename and the matching pattern parts,
438 find the stem: the part of the filename that matches the %. */
439 stem
= filename
+ (rule
->suffixes
[matches
[ri
]]
440 - rule
->targets
[matches
[ri
]]) - 1;
441 stemlen
= (namelen
- rule
->lens
[matches
[ri
]]) + 1;
442 check_lastslash
= checked_lastslash
[ri
];
449 DBS (DB_IMPLICIT
, (_("Trying pattern rule with stem `%.*s'.\n"),
450 (int) stemlen
, stem
));
452 strncpy (stem_str
, stem
, stemlen
);
453 stem_str
[stemlen
] = '\0';
455 /* If there are no prerequisites, then this rule matches. */
459 /* Temporary assign STEM to file->stem (needed to set file
461 file
->stem
= stem_str
;
463 /* Mark this rule as in use so a recursive pattern_search won't try
467 /* Try each prerequisite; see if it exists or can be created. We'll
468 build a list of prereq info in DEPLIST. Due to 2nd expansion we
469 may have to process multiple prereqs for a single dep entry. */
473 nptr
= dep_name (dep
);
476 const char *dir
= NULL
;
477 struct nameseq
*ns
, *n
;
480 /* If we need to add the directory prefix set it up. */
485 pathdir
= alloca (pathlen
+ 1);
486 memcpy (pathdir
, filename
, pathlen
);
487 pathdir
[pathlen
] = '\0';
492 /* If we're out of name to parse, start the next prereq. */
498 nptr
= dep_name (dep
);
501 /* If we don't need a second expansion, just replace the %. */
502 if (! dep
->need_2nd_expansion
)
504 p
= strchr (nptr
, '%');
506 ns_simple
.name
= nptr
;
512 memcpy (o
, filename
, pathlen
);
515 memcpy (o
, nptr
, p
- nptr
);
517 memcpy (o
, stem_str
, stemlen
);
520 ns_simple
.name
= strcache_add (depname
);
524 /* We've used up this dep, so next time get a new one. */
529 /* We have to perform second expansion on this prereq. In an
530 ideal world we would take the dependency line, substitute the
531 stem, re-expand the whole line and chop it into individual
532 prerequisites. Unfortunately this won't work because of the
533 "check_lastslash" twist. Instead, we will have to go word by
534 word, taking $()'s into account. For each word we will
535 substitute the stem, re-expand, chop it up, and, if
536 check_lastslash != 0, add the directory part to each
537 resulting prerequisite. */
544 nptr
= get_next_word (nptr
, &len
);
548 /* If the dependency name has %, substitute the stem. If we
549 just replace % with the stem value then later, when we do
550 the 2nd expansion, we will re-expand this stem value
551 again. This is not good if you have certain characters
552 in your stem (like $).
554 Instead, we will replace % with $* and allow the second
555 expansion to take care of it for us. This way (since $*
556 is a simple variable) there won't be additional
557 re-expansion of the stem. */
559 p
= lindex (nptr
, nptr
+ len
, '%');
562 memcpy (depname
, nptr
, len
);
567 unsigned int i
= p
- nptr
;
568 memcpy (depname
, nptr
, i
);
569 memcpy (depname
+ i
, "$*", 2);
570 memcpy (depname
+ i
+ 2, p
+ 1, len
- i
- 1);
571 depname
[len
+ 2 - 1] = '\0';
577 /* Set file variables. Note that we cannot do it once at the
578 beginning of the function because the stem value changes
580 if (!file_variables_set
)
582 set_file_variables (file
);
583 file_variables_set
= 1;
586 /* Perform the 2nd expansion. */
587 p
= variable_expand_for_file (depname
, file
);
589 /* Parse the expanded string. */
590 ns
= parse_file_seq (&p
, sizeof (struct dep
),
591 order_only
? '\0' : '|',
592 add_dir
? dir
: NULL
, 0);
594 for (n
= ns
; n
!= NULL
; n
= n
->next
)
597 /* Set up for the next word. */
601 /* If there are more than max_pattern_deps prerequisites (due to
602 2nd expansion), reset it and realloc the arrays. */
604 if (deps_found
> max_pattern_deps
)
606 unsigned int l
= pat
- deplist
;
607 deplist
= xrealloc (deplist
,
608 deps_found
* sizeof (struct patdeps
));
610 max_pattern_deps
= deps_found
;
613 /* Go through the nameseq and handle each as a prereq name. */
614 for (n
= ns
; n
!= 0; n
= n
->next
)
617 int is_rule
= n
->name
== dep_name (dep
);
619 if (file_impossible_p (n
->name
))
621 /* If this prereq has already been ruled "impossible",
622 then the rule fails. Don't bother trying it on the
623 second pass either since we know that will fail. */
626 ? _("Rejecting impossible rule prerequisite `%s'.\n")
627 : _("Rejecting impossible implicit prerequisite `%s'.\n"),
635 memset (pat
, '\0', sizeof (struct patdeps
));
636 pat
->ignore_mtime
= dep
->ignore_mtime
;
640 ? _("Trying rule prerequisite `%s'.\n")
641 : _("Trying implicit prerequisite `%s'.\n"), n
->name
));
643 /* If this prereq is also explicitly mentioned for FILE,
644 skip all tests below since it must be built no matter
645 which implicit rule we choose. */
647 for (expl_d
= file
->deps
; expl_d
!= 0; expl_d
= expl_d
->next
)
648 if (streq (dep_name (expl_d
), n
->name
))
652 (pat
++)->name
= n
->name
;
656 /* The DEP->changed flag says that this dependency resides
657 in a nonexistent directory. So we normally can skip
658 looking for the file. However, if CHECK_LASTSLASH is
659 set, then the dependency file we are actually looking for
660 is in a different directory (the one gotten by prepending
661 FILENAME's directory), so it might actually exist. */
663 /* @@ dep->changed check is disabled. */
664 if (lookup_file (n
->name
) != 0
665 /*|| ((!dep->changed || check_lastslash) && */
666 || file_exists_p (n
->name
))
668 (pat
++)->name
= n
->name
;
672 /* This code, given FILENAME = "lib/foo.o", dependency name
673 "lib/foo.c", and VPATH=src, searches for
676 const char *vname
= vpath_search (n
->name
, 0);
680 (_("Found prerequisite `%s' as VPATH `%s'\n"),
682 (pat
++)->name
= n
->name
;
687 /* We could not find the file in any place we should look.
688 Try to make this dependency as an intermediate file, but
689 only on the second pass. */
694 (_("Looking for a rule with intermediate file `%s'.\n"),
698 int_file
= alloca (sizeof (struct file
));
699 memset (int_file
, '\0', sizeof (struct file
));
700 int_file
->name
= n
->name
;
702 if (pattern_search (int_file
,
707 pat
->pattern
= int_file
->name
;
708 int_file
->name
= n
->name
;
709 pat
->file
= int_file
;
710 (pat
++)->name
= n
->name
;
715 /* If we have tried to find P as an intermediate file
716 and failed, mark that name as impossible so we won't
717 go through the search again later. */
718 if (int_file
->variables
)
719 free_variable_set (int_file
->variables
);
720 file_impossible (n
->name
);
723 /* A dependency of this rule does not exist. Therefore, this
729 /* Free the ns chain. */
730 if (ns
!= &ns_simple
)
737 /* Reset the stem in FILE. */
741 /* This rule is no longer `in use' for recursive searches. */
745 /* This pattern rule does apply. Stop looking for one. */
748 /* This pattern rule does not apply. If some of its dependencies
749 succeeded, free the data structure describing them. */
750 /* free_idep_chain (deps); */
754 /* If we found an applicable rule without intermediate files, don't try
762 /* RULE is nil if the loop went through the list but everything failed. */
768 /* If we are recursing, store the pattern that matched FILENAME in
769 FILE->name for use in upper levels. */
773 file
->name
= rule
->targets
[matches
[foundrule
]];
775 /* DEPLIST lists the prerequisites for the rule we found. This includes the
776 intermediate files, if any. Convert them into entries on the deps-chain
779 while (pat
-- > deplist
)
786 /* If we need to use an intermediate file, make sure it is entered
787 as a target, with the info that was found for it in the recursive
788 pattern_search call. We know that the intermediate file did not
789 already exist as a target; therefore we can assume that the deps
790 and cmds of F below are null before we change them. */
792 struct file
*imf
= pat
->file
;
793 struct file
*f
= lookup_file (imf
->name
);
795 /* We don't want to delete an intermediate file that happened
796 to be a prerequisite of some (other) target. Mark it as
801 f
= enter_file (imf
->name
);
806 f
->also_make
= imf
->also_make
;
809 f
->tried_implicit
= 1;
811 imf
= lookup_file (pat
->pattern
);
812 if (imf
!= 0 && imf
->precious
)
815 for (dep
= f
->deps
; dep
!= 0; dep
= dep
->next
)
817 dep
->file
= enter_file (dep
->name
);
819 dep
->file
->tried_implicit
|= dep
->changed
;
824 dep
->ignore_mtime
= pat
->ignore_mtime
;
825 s
= strcache_add (pat
->name
);
830 dep
->file
= lookup_file (s
);
832 dep
->file
= enter_file (s
);
835 if (pat
->file
== 0 && tryrules
[foundrule
]->terminal
)
837 /* If the file actually existed (was not an intermediate file), and
838 the rule that found it was a terminal one, then we want to mark
839 the found file so that it will not have implicit rule search done
840 for it. If we are not entering a `struct file' for it now, we
841 indicate this with the `changed' flag. */
845 dep
->file
->tried_implicit
= 1;
848 dep
->next
= file
->deps
;
852 if (!checked_lastslash
[foundrule
])
854 /* Always allocate new storage, since STEM might be on the stack for an
855 intermediate file. */
856 file
->stem
= strcache_add_len (stem
, stemlen
);
857 fullstemlen
= stemlen
;
861 int dirlen
= (lastslash
+ 1) - filename
;
864 /* We want to prepend the directory from
865 the original FILENAME onto the stem. */
866 fullstemlen
= dirlen
+ stemlen
;
867 sp
= alloca (fullstemlen
+ 1);
868 memcpy (sp
, filename
, dirlen
);
869 memcpy (sp
+ dirlen
, stem
, stemlen
);
870 sp
[fullstemlen
] = '\0';
871 file
->stem
= strcache_add (sp
);
874 file
->cmds
= rule
->cmds
;
877 /* Set precious flag. */
879 struct file
*f
= lookup_file (rule
->targets
[matches
[foundrule
]]);
880 if (f
&& f
->precious
)
884 /* If this rule builds other targets, too, put the others into FILE's
885 `also_make' member. */
888 for (ri
= 0; ri
< rule
->num
; ++ri
)
889 if (ri
!= matches
[foundrule
])
891 char *nm
= alloca (rule
->lens
[ri
] + fullstemlen
+ 1);
894 struct dep
*new = alloc_dep ();
896 /* GKM FIMXE: handle '|' here too */
897 memcpy (p
, rule
->targets
[ri
],
898 rule
->suffixes
[ri
] - rule
->targets
[ri
] - 1);
899 p
+= rule
->suffixes
[ri
] - rule
->targets
[ri
] - 1;
900 memcpy (p
, file
->stem
, fullstemlen
);
902 memcpy (p
, rule
->suffixes
[ri
],
903 rule
->lens
[ri
] - (rule
->suffixes
[ri
] - rule
->targets
[ri
])+1);
904 new->name
= strcache_add (nm
);
905 new->file
= enter_file (new->name
);
906 new->next
= file
->also_make
;
908 /* Set precious flag. */
909 f
= lookup_file (rule
->targets
[ri
]);
910 if (f
&& f
->precious
)
911 new->file
->precious
= 1;
913 /* Set the is_target flag so that this file is not treated as
914 intermediate by the pattern rule search algorithm and
915 file_exists_p cannot pick it up yet. */
916 new->file
->is_target
= 1;
918 file
->also_make
= new;