2 * "Optimize" a list of dependencies as spit out by gcc -MD
4 * ===========================================================================
6 * Author Kai Germaschewski
7 * Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de>
9 * This software may be used and distributed according to the terms
10 * of the GNU General Public License, incorporated herein by reference.
15 * gcc produces a very nice and correct list of dependencies which
16 * tells make when to remake a file.
18 * To use this list as-is however has the drawback that virtually
19 * every file in the kernel includes <linux/config.h> which then again
20 * includes <linux/autoconf.h>
22 * If the user re-runs make *config, linux/autoconf.h will be
23 * regenerated. make notices that and will rebuild every file which
24 * includes autoconf.h, i.e. basically all files. This is extremely
25 * annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
27 * So we play the same trick that "mkdep" played before. We replace
28 * the dependency on linux/autoconf.h by a dependency on every config
29 * option which is mentioned in any of the listed prequisites.
31 * To be exact, split-include populates a tree in include/config/,
32 * e.g. include/config/his/driver.h, which contains the #define/#undef
33 * for the CONFIG_HIS_DRIVER option.
35 * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
36 * which depend on "include/linux/config/his/driver.h" will be rebuilt,
37 * so most likely only his driver ;-)
39 * The idea above dates, by the way, back to Michael E Chastain, AFAIK.
41 * So to get dependencies right, there are two issues:
42 * o if any of the files the compiler read changed, we need to rebuild
43 * o if the command line given to the compile the file changed, we
44 * better rebuild as well.
46 * The former is handled by using the -MD output, the later by saving
47 * the command line used to compile the old object and comparing it
48 * to the one we would now use.
50 * Again, also this idea is pretty old and has been discussed on
51 * kbuild-devel a long time ago. I don't have a sensibly working
52 * internet connection right now, so I rather don't mention names
53 * without double checking.
55 * This code here has been based partially based on mkdep.c, which
56 * says the following about its history:
58 * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
59 * This is a C version of syncdep.pl by Werner Almesberger.
64 * fixdep <depfile> <target> <cmdline>
66 * and will read the dependency file <depfile>
68 * The transformed dependency snipped is written to stdout.
70 * It first generates a line
72 * cmd_<target> = <cmdline>
74 * and then basically copies the .<target>.d file to stdout, in the
75 * process filtering out the dependency on linux/autoconf.h and adding
76 * dependencies on include/config/my/option.h for every
77 * CONFIG_MY_OPTION encountered in any of the prequisites.
79 * It will also filter out all the dependencies on *.ver. We need
80 * to make sure that the generated version checksum are globally up
81 * to date before even starting the recursive build, so it's too late
82 * at this point anyway.
84 * The algorithm to grep for "CONFIG_..." is bit unusual, but should
85 * be fast ;-) We don't even try to really parse the header files, but
86 * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
87 * be picked up as well. It's not a problem with respect to
88 * correctness, since that can only give too many dependencies, thus
89 * we cannot miss a rebuild. Since people tend to not mention totally
90 * unrelated CONFIG_ options all over the place, it's not an
91 * efficiency problem either.
93 * (Note: it'd be easy to port over the complete mkdep state machine,
94 * but I don't think the added complexity is worth it)
97 * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto
98 * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not
99 * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as
100 * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,
101 * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that
102 * those files will have correct dependencies.
105 #include <sys/types.h>
106 #include <sys/stat.h>
107 #include <sys/mman.h>
115 #include <arpa/inet.h>
119 #define INT_CONF ntohl(0x434f4e46)
120 #define INT_ONFI ntohl(0x4f4e4649)
121 #define INT_NFIG ntohl(0x4e464947)
122 #define INT_FIG_ ntohl(0x4649475f)
132 fprintf(stderr
, "Usage: fixdep <depfile> <target> <cmdline>\n");
137 * Print out the commandline prefixed with cmd_<target filename> :=
139 void print_cmdline(void)
141 printf("cmd_%s := %s\n\n", target
, cmdline
);
144 char * str_config
= NULL
;
149 * Grow the configuration string to a desired length.
150 * Usually the first growth is plenty.
152 void grow_config(int len
)
154 while (len_config
+ len
> size_config
) {
155 if (size_config
== 0)
157 str_config
= realloc(str_config
, size_config
*= 2);
158 if (str_config
== NULL
)
159 { perror("fixdep:malloc"); exit(1); }
166 * Lookup a value in the configuration string.
168 int is_defined_config(const char * name
, int len
)
170 const char * pconfig
;
171 const char * plast
= str_config
+ len_config
- len
;
172 for ( pconfig
= str_config
+ 1; pconfig
< plast
; pconfig
++ ) {
173 if (pconfig
[ -1] == '\n'
174 && pconfig
[len
] == '\n'
175 && !memcmp(pconfig
, name
, len
))
182 * Add a new value to the configuration string.
184 void define_config(const char * name
, int len
)
186 grow_config(len
+ 1);
188 memcpy(str_config
+len_config
, name
, len
);
190 str_config
[len_config
++] = '\n';
194 * Clear the set of configuration strings.
196 void clear_config(void)
199 define_config("", 0);
203 * Record the use of a CONFIG_* word.
205 void use_config(char *m
, int slen
)
207 char *s
= alloca(slen
+1);
210 if (is_defined_config(m
, slen
))
213 define_config(m
, slen
);
215 memcpy(s
, m
, slen
); s
[slen
] = 0;
217 for (p
= s
; p
< s
+ slen
; p
++) {
221 *p
= tolower((int)*p
);
223 printf(" $(wildcard include/config/%s.h) \\\n", s
);
226 void parse_config_file(char *map
, size_t len
)
228 /* modified for bbox */
229 char *end_3
= map
+ len
- 3; /* 3 == length of "IF_" */
230 char *end_7
= map
+ len
- 7;
235 for (; p
<= end_3
; p
++) {
236 /* Find next identifier's beginning */
237 if (!(isalnum(*p
) || *p
== '_'))
241 if (p
< end_7
&& p
[6] == '_') {
242 if (!memcmp(p
, "CONFIG", 6)) goto conf7
;
243 if (!memcmp(p
, "ENABLE", 6)) goto conf7
;
244 if (!memcmp(p
, "IF_NOT", 6)) goto conf7
;
246 /* we have at least 3 chars because of p <= end_3 */
247 /*if (!memcmp(p, "IF_", 3)) ...*/
248 if (p
[0] == 'I' && p
[1] == 'F' && p
[2] == '_') {
253 /* This identifier is not interesting, skip it */
254 while (p
<= end_3
&& (isalnum(*p
) || *p
== '_'))
261 for (q
= p
; q
< end_3
+3; q
++) {
262 if (!(isalnum(*q
) || *q
== '_'))
271 /* test is s ends in sub */
272 int strrcmp(char *s
, char *sub
)
274 int slen
= strlen(s
);
275 int sublen
= strlen(sub
);
280 return memcmp(s
+ slen
- sublen
, sub
, sublen
);
283 void do_config_file(char *filename
)
289 fd
= open(filename
, O_RDONLY
);
291 fprintf(stderr
, "fixdep: ");
296 if (st
.st_size
== 0) {
300 map
= mmap(NULL
, st
.st_size
, PROT_READ
, MAP_PRIVATE
, fd
, 0);
301 if ((long) map
== -1) {
302 perror("fixdep: mmap");
307 parse_config_file(map
, st
.st_size
);
309 munmap(map
, st
.st_size
);
314 void parse_dep_file(void *map
, size_t len
)
319 char *s
= alloca(len
);
321 p
= memchr(m
, ':', len
);
323 fprintf(stderr
, "fixdep: parse error\n");
326 memcpy(s
, m
, p
-m
); s
[p
-m
] = 0;
327 printf("deps_%s := \\\n", target
);
333 while (m
< end
&& (*m
== ' ' || *m
== '\\' || *m
== '\n' || *m
== '\r'))
336 while (p
< end
&& *p
!= ' ') p
++;
338 do p
--; while (!isalnum(*p
));
341 memcpy(s
, m
, p
-m
); s
[p
-m
] = 0;
342 if (strrcmp(s
, "include/autoconf.h") &&
343 strrcmp(s
, "arch/um/include/uml-config.h") &&
344 strrcmp(s
, ".ver")) {
345 printf(" %s \\\n", s
);
350 printf("\n%s: $(deps_%s)\n\n", target
, target
);
351 printf("$(deps_%s):\n", target
);
354 void print_deps(void)
360 fd
= open(depfile
, O_RDONLY
);
362 fprintf(stderr
, "fixdep: ");
367 if (st
.st_size
== 0) {
368 fprintf(stderr
,"fixdep: %s is empty\n",depfile
);
372 map
= mmap(NULL
, st
.st_size
, PROT_READ
, MAP_PRIVATE
, fd
, 0);
373 if ((long) map
== -1) {
374 perror("fixdep: mmap");
379 parse_dep_file(map
, st
.st_size
);
381 munmap(map
, st
.st_size
);
389 static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
391 if (*(int *)test != INT_CONF) {
392 fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
399 int main(int argc
, char **argv
)