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22433fc5 MY |
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 <[email protected]> | |
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 | |
19 | * every file in the kernel includes autoconf.h. | |
20 | * | |
21 | * If the user re-runs make *config, 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 autoconf.h by a dependency on every config | |
28 | * option which is mentioned in any of the listed prequisites. | |
29 | * | |
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. | |
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:[email protected]>. | |
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 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 | ||
127 | static void usage(void) | |
128 | { | |
129 | fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n"); | |
130 | exit(1); | |
131 | } | |
132 | ||
133 | /* | |
134 | * Print out the commandline prefixed with cmd_<target filename> := | |
135 | */ | |
136 | static void print_cmdline(void) | |
137 | { | |
138 | printf("cmd_%s := %s\n\n", target, cmdline); | |
139 | } | |
140 | ||
141 | struct item { | |
142 | struct item *next; | |
143 | unsigned int len; | |
144 | unsigned int hash; | |
145 | char name[0]; | |
146 | }; | |
147 | ||
148 | #define HASHSZ 256 | |
149 | static struct item *hashtab[HASHSZ]; | |
150 | ||
151 | static unsigned int strhash(const char *str, unsigned int sz) | |
152 | { | |
153 | /* fnv32 hash */ | |
154 | unsigned int i, hash = 2166136261U; | |
155 | ||
156 | for (i = 0; i < sz; i++) | |
157 | hash = (hash ^ str[i]) * 0x01000193; | |
158 | return hash; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Lookup a value in the configuration string. | |
163 | */ | |
164 | static int is_defined_config(const char *name, int len, unsigned int hash) | |
165 | { | |
166 | struct item *aux; | |
167 | ||
168 | for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) { | |
169 | if (aux->hash == hash && aux->len == len && | |
170 | memcmp(aux->name, name, len) == 0) | |
171 | return 1; | |
172 | } | |
173 | return 0; | |
174 | } | |
175 | ||
176 | /* | |
177 | * Add a new value to the configuration string. | |
178 | */ | |
179 | static void define_config(const char *name, int len, unsigned int hash) | |
180 | { | |
181 | struct item *aux = malloc(sizeof(*aux) + len); | |
182 | ||
183 | if (!aux) { | |
184 | perror("fixdep:malloc"); | |
185 | exit(1); | |
186 | } | |
187 | memcpy(aux->name, name, len); | |
188 | aux->len = len; | |
189 | aux->hash = hash; | |
190 | aux->next = hashtab[hash % HASHSZ]; | |
191 | hashtab[hash % HASHSZ] = aux; | |
192 | } | |
193 | ||
194 | /* | |
195 | * Clear the set of configuration strings. | |
196 | */ | |
197 | static void clear_config(void) | |
198 | { | |
199 | struct item *aux, *next; | |
200 | unsigned int i; | |
201 | ||
202 | for (i = 0; i < HASHSZ; i++) { | |
203 | for (aux = hashtab[i]; aux; aux = next) { | |
204 | next = aux->next; | |
205 | free(aux); | |
206 | } | |
207 | hashtab[i] = NULL; | |
208 | } | |
209 | } | |
210 | ||
211 | /* | |
212 | * Record the use of a CONFIG_* word. | |
213 | */ | |
214 | static void use_config(const char *m, int slen) | |
215 | { | |
216 | unsigned int hash = strhash(m, slen); | |
217 | int c, i; | |
218 | ||
219 | if (is_defined_config(m, slen, hash)) | |
220 | return; | |
221 | ||
222 | define_config(m, slen, hash); | |
223 | ||
fc196d0e | 224 | printf(" $(wildcard include/config/"); |
22433fc5 MY |
225 | for (i = 0; i < slen; i++) { |
226 | c = m[i]; | |
227 | if (c == '_') | |
228 | c = '/'; | |
229 | else | |
230 | c = tolower(c); | |
231 | putchar(c); | |
232 | } | |
233 | printf(".h) \\\n"); | |
234 | } | |
235 | ||
236 | static void parse_config_file(const char *map, size_t len) | |
237 | { | |
238 | const int *end = (const int *) (map + len); | |
239 | /* start at +1, so that p can never be < map */ | |
240 | const int *m = (const int *) map + 1; | |
241 | const char *p, *q; | |
242 | ||
243 | for (; m < end; m++) { | |
244 | if (*m == INT_CONF) { p = (char *) m ; goto conf; } | |
245 | if (*m == INT_ONFI) { p = (char *) m-1; goto conf; } | |
246 | if (*m == INT_NFIG) { p = (char *) m-2; goto conf; } | |
247 | if (*m == INT_FIG_) { p = (char *) m-3; goto conf; } | |
248 | continue; | |
249 | conf: | |
250 | if (p > map + len - 7) | |
251 | continue; | |
252 | if (memcmp(p, "CONFIG_", 7)) | |
253 | continue; | |
29974f77 MY |
254 | p += 7; |
255 | for (q = p; q < map + len; q++) { | |
22433fc5 MY |
256 | if (!(isalnum(*q) || *q == '_')) |
257 | goto found; | |
258 | } | |
259 | continue; | |
260 | ||
261 | found: | |
262 | if (!memcmp(q - 7, "_MODULE", 7)) | |
263 | q -= 7; | |
29974f77 | 264 | if (q - p < 0) |
22433fc5 | 265 | continue; |
29974f77 | 266 | use_config(p, q - p); |
22433fc5 MY |
267 | } |
268 | } | |
269 | ||
270 | /* test is s ends in sub */ | |
271 | static int strrcmp(char *s, char *sub) | |
272 | { | |
273 | int slen = strlen(s); | |
274 | int sublen = strlen(sub); | |
275 | ||
276 | if (sublen > slen) | |
277 | return 1; | |
278 | ||
279 | return memcmp(s + slen - sublen, sub, sublen); | |
280 | } | |
281 | ||
282 | static void do_config_file(const char *filename) | |
283 | { | |
284 | struct stat st; | |
285 | int fd; | |
286 | void *map; | |
287 | ||
288 | fd = open(filename, O_RDONLY); | |
289 | if (fd < 0) { | |
290 | fprintf(stderr, "fixdep: error opening config file: "); | |
291 | perror(filename); | |
292 | exit(2); | |
293 | } | |
294 | fstat(fd, &st); | |
295 | if (st.st_size == 0) { | |
296 | close(fd); | |
297 | return; | |
298 | } | |
299 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
300 | if ((long) map == -1) { | |
301 | perror("fixdep: mmap"); | |
302 | close(fd); | |
303 | return; | |
304 | } | |
305 | ||
306 | parse_config_file(map, st.st_size); | |
307 | ||
308 | munmap(map, st.st_size); | |
309 | ||
310 | close(fd); | |
311 | } | |
312 | ||
313 | /* | |
314 | * Important: The below generated source_foo.o and deps_foo.o variable | |
315 | * assignments are parsed not only by make, but also by the rather simple | |
316 | * parser in scripts/mod/sumversion.c. | |
317 | */ | |
318 | static void parse_dep_file(void *map, size_t len) | |
319 | { | |
320 | char *m = map; | |
321 | char *end = m + len; | |
322 | char *p; | |
323 | char s[PATH_MAX]; | |
324 | int is_target; | |
325 | int saw_any_target = 0; | |
326 | int is_first_dep = 0; | |
327 | ||
328 | clear_config(); | |
329 | ||
330 | while (m < end) { | |
331 | /* Skip any "white space" */ | |
332 | while (m < end && (*m == ' ' || *m == '\\' || *m == '\n')) | |
333 | m++; | |
334 | /* Find next "white space" */ | |
335 | p = m; | |
336 | while (p < end && *p != ' ' && *p != '\\' && *p != '\n') | |
337 | p++; | |
338 | /* Is the token we found a target name? */ | |
339 | is_target = (*(p-1) == ':'); | |
340 | /* Don't write any target names into the dependency file */ | |
341 | if (is_target) { | |
342 | /* The /next/ file is the first dependency */ | |
343 | is_first_dep = 1; | |
344 | } else { | |
345 | /* Save this token/filename */ | |
346 | memcpy(s, m, p-m); | |
347 | s[p - m] = 0; | |
348 | ||
349 | /* Ignore certain dependencies */ | |
350 | if (strrcmp(s, "include/generated/autoconf.h") && | |
351 | strrcmp(s, "arch/um/include/uml-config.h") && | |
352 | strrcmp(s, "include/linux/kconfig.h") && | |
353 | strrcmp(s, ".ver")) { | |
354 | /* | |
355 | * Do not list the source file as dependency, | |
356 | * so that kbuild is not confused if a .c file | |
357 | * is rewritten into .S or vice versa. Storing | |
358 | * it in source_* is needed for modpost to | |
359 | * compute srcversions. | |
360 | */ | |
361 | if (is_first_dep) { | |
362 | /* | |
363 | * If processing the concatenation of | |
364 | * multiple dependency files, only | |
365 | * process the first target name, which | |
366 | * will be the original source name, | |
367 | * and ignore any other target names, | |
368 | * which will be intermediate temporary | |
369 | * files. | |
370 | */ | |
371 | if (!saw_any_target) { | |
372 | saw_any_target = 1; | |
373 | printf("source_%s := %s\n\n", | |
374 | target, s); | |
375 | printf("deps_%s := \\\n", | |
376 | target); | |
377 | } | |
378 | is_first_dep = 0; | |
379 | } else | |
380 | printf(" %s \\\n", s); | |
381 | do_config_file(s); | |
382 | } | |
383 | } | |
384 | /* | |
385 | * Start searching for next token immediately after the first | |
386 | * "whitespace" character that follows this token. | |
387 | */ | |
388 | m = p + 1; | |
389 | } | |
390 | ||
391 | if (!saw_any_target) { | |
392 | fprintf(stderr, "fixdep: parse error; no targets found\n"); | |
393 | exit(1); | |
394 | } | |
395 | ||
396 | printf("\n%s: $(deps_%s)\n\n", target, target); | |
397 | printf("$(deps_%s):\n", target); | |
398 | } | |
399 | ||
400 | static void print_deps(void) | |
401 | { | |
402 | struct stat st; | |
403 | int fd; | |
404 | void *map; | |
405 | ||
406 | fd = open(depfile, O_RDONLY); | |
407 | if (fd < 0) { | |
408 | fprintf(stderr, "fixdep: error opening depfile: "); | |
409 | perror(depfile); | |
410 | exit(2); | |
411 | } | |
412 | if (fstat(fd, &st) < 0) { | |
45f0ad95 MY |
413 | fprintf(stderr, "fixdep: error fstat'ing depfile: "); |
414 | perror(depfile); | |
415 | exit(2); | |
416 | } | |
22433fc5 MY |
417 | if (st.st_size == 0) { |
418 | fprintf(stderr,"fixdep: %s is empty\n",depfile); | |
419 | close(fd); | |
420 | return; | |
421 | } | |
422 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
423 | if ((long) map == -1) { | |
424 | perror("fixdep: mmap"); | |
425 | close(fd); | |
426 | return; | |
427 | } | |
428 | ||
429 | parse_dep_file(map, st.st_size); | |
430 | ||
431 | munmap(map, st.st_size); | |
432 | ||
433 | close(fd); | |
434 | } | |
435 | ||
436 | static void traps(void) | |
437 | { | |
438 | static char test[] __attribute__((aligned(sizeof(int)))) = "CONF"; | |
439 | int *p = (int *)test; | |
440 | ||
441 | if (*p != INT_CONF) { | |
442 | fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianness? %#x\n", | |
443 | *p); | |
444 | exit(2); | |
445 | } | |
446 | } | |
447 | ||
448 | int main(int argc, char *argv[]) | |
449 | { | |
450 | traps(); | |
451 | ||
452 | if (argc != 4) | |
453 | usage(); | |
454 | ||
455 | depfile = argv[1]; | |
456 | target = argv[2]; | |
457 | cmdline = argv[3]; | |
458 | ||
459 | print_cmdline(); | |
460 | print_deps(); | |
461 | ||
462 | return 0; | |
463 | } |