Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * "Optimize" a list of dependencies as spit out by gcc -MD | |
3 | * for the kernel build | |
4 | * =========================================================================== | |
5 | * | |
6 | * Author Kai Germaschewski | |
7 | * Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de> | |
8 | * | |
9 | * This software may be used and distributed according to the terms | |
10 | * of the GNU General Public License, incorporated herein by reference. | |
11 | * | |
12 | * | |
13 | * Introduction: | |
14 | * | |
15 | * gcc produces a very nice and correct list of dependencies which | |
16 | * tells make when to remake a file. | |
17 | * | |
18 | * To use this list as-is however has the drawback that virtually | |
7d3392e5 | 19 | * every file in the kernel includes <linux/autoconf.h>. |
1da177e4 LT |
20 | * |
21 | * If the user re-runs make *config, linux/autoconf.h will be | |
22 | * regenerated. make notices that and will rebuild every file which | |
23 | * includes autoconf.h, i.e. basically all files. This is extremely | |
24 | * annoying if the user just changed CONFIG_HIS_DRIVER from n to m. | |
25 | * | |
26 | * So we play the same trick that "mkdep" played before. We replace | |
27 | * the dependency on linux/autoconf.h by a dependency on every config | |
28 | * option which is mentioned in any of the listed prequisites. | |
29 | * | |
c21b1e4d JB |
30 | * kconfig populates a tree in include/config/ with an empty file |
31 | * for each config symbol and when the configuration is updated | |
32 | * the files representing changed config options are touched | |
33 | * which then let make pick up the changes and the files that use | |
34 | * the config symbols are rebuilt. | |
1da177e4 LT |
35 | * |
36 | * So if the user changes his CONFIG_HIS_DRIVER option, only the objects | |
37 | * which depend on "include/linux/config/his/driver.h" will be rebuilt, | |
38 | * so most likely only his driver ;-) | |
39 | * | |
40 | * The idea above dates, by the way, back to Michael E Chastain, AFAIK. | |
41 | * | |
42 | * So to get dependencies right, there are two issues: | |
43 | * o if any of the files the compiler read changed, we need to rebuild | |
44 | * o if the command line given to the compile the file changed, we | |
45 | * better rebuild as well. | |
46 | * | |
47 | * The former is handled by using the -MD output, the later by saving | |
48 | * the command line used to compile the old object and comparing it | |
49 | * to the one we would now use. | |
50 | * | |
51 | * Again, also this idea is pretty old and has been discussed on | |
52 | * kbuild-devel a long time ago. I don't have a sensibly working | |
53 | * internet connection right now, so I rather don't mention names | |
54 | * without double checking. | |
55 | * | |
56 | * This code here has been based partially based on mkdep.c, which | |
57 | * says the following about its history: | |
58 | * | |
59 | * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>. | |
60 | * This is a C version of syncdep.pl by Werner Almesberger. | |
61 | * | |
62 | * | |
63 | * It is invoked as | |
64 | * | |
65 | * fixdep <depfile> <target> <cmdline> | |
66 | * | |
67 | * and will read the dependency file <depfile> | |
68 | * | |
69 | * The transformed dependency snipped is written to stdout. | |
70 | * | |
71 | * It first generates a line | |
72 | * | |
73 | * cmd_<target> = <cmdline> | |
74 | * | |
75 | * and then basically copies the .<target>.d file to stdout, in the | |
76 | * process filtering out the dependency on linux/autoconf.h and adding | |
77 | * dependencies on include/config/my/option.h for every | |
78 | * CONFIG_MY_OPTION encountered in any of the prequisites. | |
79 | * | |
80 | * It will also filter out all the dependencies on *.ver. We need | |
81 | * to make sure that the generated version checksum are globally up | |
82 | * to date before even starting the recursive build, so it's too late | |
83 | * at this point anyway. | |
84 | * | |
85 | * The algorithm to grep for "CONFIG_..." is bit unusual, but should | |
86 | * be fast ;-) We don't even try to really parse the header files, but | |
87 | * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will | |
88 | * be picked up as well. It's not a problem with respect to | |
89 | * correctness, since that can only give too many dependencies, thus | |
90 | * we cannot miss a rebuild. Since people tend to not mention totally | |
91 | * unrelated CONFIG_ options all over the place, it's not an | |
92 | * efficiency problem either. | |
93 | * | |
94 | * (Note: it'd be easy to port over the complete mkdep state machine, | |
95 | * but I don't think the added complexity is worth it) | |
96 | */ | |
97 | /* | |
98 | * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto | |
99 | * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not | |
100 | * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as | |
101 | * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h, | |
102 | * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that | |
103 | * those files will have correct dependencies. | |
104 | */ | |
105 | ||
106 | #include <sys/types.h> | |
107 | #include <sys/stat.h> | |
108 | #include <sys/mman.h> | |
109 | #include <unistd.h> | |
110 | #include <fcntl.h> | |
111 | #include <string.h> | |
112 | #include <stdlib.h> | |
113 | #include <stdio.h> | |
114 | #include <limits.h> | |
115 | #include <ctype.h> | |
116 | #include <arpa/inet.h> | |
117 | ||
118 | #define INT_CONF ntohl(0x434f4e46) | |
119 | #define INT_ONFI ntohl(0x4f4e4649) | |
120 | #define INT_NFIG ntohl(0x4e464947) | |
121 | #define INT_FIG_ ntohl(0x4649475f) | |
122 | ||
123 | char *target; | |
124 | char *depfile; | |
125 | char *cmdline; | |
126 | ||
4356f489 | 127 | static void usage(void) |
1da177e4 LT |
128 | { |
129 | fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n"); | |
130 | exit(1); | |
131 | } | |
132 | ||
4d99f93b SR |
133 | /* |
134 | * Print out the commandline prefixed with cmd_<target filename> := | |
6176aa9a | 135 | */ |
4356f489 | 136 | static void print_cmdline(void) |
1da177e4 | 137 | { |
6176aa9a | 138 | printf("cmd_%s := %s\n\n", target, cmdline); |
1da177e4 LT |
139 | } |
140 | ||
141 | char * str_config = NULL; | |
142 | int size_config = 0; | |
143 | int len_config = 0; | |
144 | ||
145 | /* | |
146 | * Grow the configuration string to a desired length. | |
147 | * Usually the first growth is plenty. | |
148 | */ | |
4356f489 | 149 | static void grow_config(int len) |
1da177e4 LT |
150 | { |
151 | while (len_config + len > size_config) { | |
152 | if (size_config == 0) | |
153 | size_config = 2048; | |
154 | str_config = realloc(str_config, size_config *= 2); | |
155 | if (str_config == NULL) | |
156 | { perror("fixdep:malloc"); exit(1); } | |
157 | } | |
158 | } | |
159 | ||
160 | ||
161 | ||
162 | /* | |
163 | * Lookup a value in the configuration string. | |
164 | */ | |
4356f489 | 165 | static int is_defined_config(const char * name, int len) |
1da177e4 LT |
166 | { |
167 | const char * pconfig; | |
168 | const char * plast = str_config + len_config - len; | |
169 | for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) { | |
170 | if (pconfig[ -1] == '\n' | |
171 | && pconfig[len] == '\n' | |
172 | && !memcmp(pconfig, name, len)) | |
173 | return 1; | |
174 | } | |
175 | return 0; | |
176 | } | |
177 | ||
178 | /* | |
179 | * Add a new value to the configuration string. | |
180 | */ | |
4356f489 | 181 | static void define_config(const char * name, int len) |
1da177e4 LT |
182 | { |
183 | grow_config(len + 1); | |
184 | ||
185 | memcpy(str_config+len_config, name, len); | |
186 | len_config += len; | |
187 | str_config[len_config++] = '\n'; | |
188 | } | |
189 | ||
190 | /* | |
191 | * Clear the set of configuration strings. | |
192 | */ | |
4356f489 | 193 | static void clear_config(void) |
1da177e4 LT |
194 | { |
195 | len_config = 0; | |
196 | define_config("", 0); | |
197 | } | |
198 | ||
199 | /* | |
200 | * Record the use of a CONFIG_* word. | |
201 | */ | |
4356f489 | 202 | static void use_config(char *m, int slen) |
1da177e4 LT |
203 | { |
204 | char s[PATH_MAX]; | |
205 | char *p; | |
206 | ||
207 | if (is_defined_config(m, slen)) | |
208 | return; | |
209 | ||
210 | define_config(m, slen); | |
211 | ||
212 | memcpy(s, m, slen); s[slen] = 0; | |
213 | ||
214 | for (p = s; p < s + slen; p++) { | |
215 | if (*p == '_') | |
216 | *p = '/'; | |
217 | else | |
48b9d03c | 218 | *p = tolower((int)*p); |
1da177e4 LT |
219 | } |
220 | printf(" $(wildcard include/config/%s.h) \\\n", s); | |
221 | } | |
222 | ||
4356f489 | 223 | static void parse_config_file(char *map, size_t len) |
1da177e4 LT |
224 | { |
225 | int *end = (int *) (map + len); | |
226 | /* start at +1, so that p can never be < map */ | |
227 | int *m = (int *) map + 1; | |
48b9d03c | 228 | char *p, *q; |
1da177e4 LT |
229 | |
230 | for (; m < end; m++) { | |
48b9d03c M |
231 | if (*m == INT_CONF) { p = (char *) m ; goto conf; } |
232 | if (*m == INT_ONFI) { p = (char *) m-1; goto conf; } | |
233 | if (*m == INT_NFIG) { p = (char *) m-2; goto conf; } | |
234 | if (*m == INT_FIG_) { p = (char *) m-3; goto conf; } | |
1da177e4 LT |
235 | continue; |
236 | conf: | |
237 | if (p > map + len - 7) | |
238 | continue; | |
239 | if (memcmp(p, "CONFIG_", 7)) | |
240 | continue; | |
241 | for (q = p + 7; q < map + len; q++) { | |
242 | if (!(isalnum(*q) || *q == '_')) | |
243 | goto found; | |
244 | } | |
245 | continue; | |
246 | ||
247 | found: | |
c21b1e4d JB |
248 | if (!memcmp(q - 7, "_MODULE", 7)) |
249 | q -= 7; | |
04c58f81 AG |
250 | if( (q-p-7) < 0 ) |
251 | continue; | |
1da177e4 LT |
252 | use_config(p+7, q-p-7); |
253 | } | |
254 | } | |
255 | ||
256 | /* test is s ends in sub */ | |
4356f489 | 257 | static int strrcmp(char *s, char *sub) |
1da177e4 LT |
258 | { |
259 | int slen = strlen(s); | |
260 | int sublen = strlen(sub); | |
261 | ||
262 | if (sublen > slen) | |
263 | return 1; | |
264 | ||
265 | return memcmp(s + slen - sublen, sub, sublen); | |
266 | } | |
267 | ||
4356f489 | 268 | static void do_config_file(char *filename) |
1da177e4 LT |
269 | { |
270 | struct stat st; | |
271 | int fd; | |
272 | void *map; | |
273 | ||
274 | fd = open(filename, O_RDONLY); | |
275 | if (fd < 0) { | |
276 | fprintf(stderr, "fixdep: "); | |
277 | perror(filename); | |
278 | exit(2); | |
279 | } | |
280 | fstat(fd, &st); | |
281 | if (st.st_size == 0) { | |
282 | close(fd); | |
283 | return; | |
284 | } | |
285 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
286 | if ((long) map == -1) { | |
287 | perror("fixdep: mmap"); | |
288 | close(fd); | |
289 | return; | |
290 | } | |
291 | ||
292 | parse_config_file(map, st.st_size); | |
293 | ||
294 | munmap(map, st.st_size); | |
295 | ||
296 | close(fd); | |
297 | } | |
298 | ||
4356f489 | 299 | static void parse_dep_file(void *map, size_t len) |
1da177e4 | 300 | { |
48b9d03c M |
301 | char *m = map; |
302 | char *end = m + len; | |
303 | char *p; | |
1da177e4 LT |
304 | char s[PATH_MAX]; |
305 | ||
306 | p = strchr(m, ':'); | |
307 | if (!p) { | |
308 | fprintf(stderr, "fixdep: parse error\n"); | |
309 | exit(1); | |
310 | } | |
311 | memcpy(s, m, p-m); s[p-m] = 0; | |
312 | printf("deps_%s := \\\n", target); | |
313 | m = p+1; | |
314 | ||
315 | clear_config(); | |
316 | ||
317 | while (m < end) { | |
318 | while (m < end && (*m == ' ' || *m == '\\' || *m == '\n')) | |
319 | m++; | |
320 | p = m; | |
321 | while (p < end && *p != ' ') p++; | |
322 | if (p == end) { | |
323 | do p--; while (!isalnum(*p)); | |
324 | p++; | |
325 | } | |
326 | memcpy(s, m, p-m); s[p-m] = 0; | |
327 | if (strrcmp(s, "include/linux/autoconf.h") && | |
328 | strrcmp(s, "arch/um/include/uml-config.h") && | |
329 | strrcmp(s, ".ver")) { | |
330 | printf(" %s \\\n", s); | |
331 | do_config_file(s); | |
332 | } | |
333 | m = p + 1; | |
334 | } | |
335 | printf("\n%s: $(deps_%s)\n\n", target, target); | |
336 | printf("$(deps_%s):\n", target); | |
337 | } | |
338 | ||
4356f489 | 339 | static void print_deps(void) |
1da177e4 LT |
340 | { |
341 | struct stat st; | |
342 | int fd; | |
343 | void *map; | |
344 | ||
345 | fd = open(depfile, O_RDONLY); | |
346 | if (fd < 0) { | |
347 | fprintf(stderr, "fixdep: "); | |
348 | perror(depfile); | |
349 | exit(2); | |
350 | } | |
351 | fstat(fd, &st); | |
352 | if (st.st_size == 0) { | |
353 | fprintf(stderr,"fixdep: %s is empty\n",depfile); | |
354 | close(fd); | |
355 | return; | |
356 | } | |
357 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
358 | if ((long) map == -1) { | |
359 | perror("fixdep: mmap"); | |
360 | close(fd); | |
361 | return; | |
362 | } | |
363 | ||
364 | parse_dep_file(map, st.st_size); | |
365 | ||
366 | munmap(map, st.st_size); | |
367 | ||
368 | close(fd); | |
369 | } | |
370 | ||
4356f489 | 371 | static void traps(void) |
1da177e4 LT |
372 | { |
373 | static char test[] __attribute__((aligned(sizeof(int)))) = "CONF"; | |
d067aa74 | 374 | int *p = (int *)test; |
1da177e4 | 375 | |
d067aa74 | 376 | if (*p != INT_CONF) { |
1da177e4 | 377 | fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n", |
d067aa74 | 378 | *p); |
1da177e4 LT |
379 | exit(2); |
380 | } | |
381 | } | |
382 | ||
383 | int main(int argc, char *argv[]) | |
384 | { | |
385 | traps(); | |
386 | ||
387 | if (argc != 4) | |
388 | usage(); | |
389 | ||
390 | depfile = argv[1]; | |
391 | target = argv[2]; | |
392 | cmdline = argv[3]; | |
393 | ||
394 | print_cmdline(); | |
395 | print_deps(); | |
396 | ||
397 | return 0; | |
398 | } |