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 | |
264a2683 | 19 | * every file in the kernel includes autoconf.h. |
1da177e4 | 20 | * |
264a2683 | 21 | * If the user re-runs make *config, autoconf.h will be |
1da177e4 LT |
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 | |
264a2683 | 27 | * the dependency on autoconf.h by a dependency on every config |
4e433fc4 | 28 | * option which is mentioned in any of the listed prerequisites. |
1da177e4 | 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 | |
4e433fc4 | 37 | * which depend on "include/config/his/driver.h" will be rebuilt, |
1da177e4 LT |
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 | |
264a2683 | 76 | * process filtering out the dependency on autoconf.h and adding |
1da177e4 | 77 | * dependencies on include/config/my/option.h for every |
4e433fc4 | 78 | * CONFIG_MY_OPTION encountered in any of the prerequisites. |
1da177e4 LT |
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 | * | |
dee81e98 | 85 | * We don't even try to really parse the header files, but |
1da177e4 LT |
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. | |
92 | * | |
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) | |
95 | */ | |
1da177e4 LT |
96 | |
97 | #include <sys/types.h> | |
98 | #include <sys/stat.h> | |
1da177e4 LT |
99 | #include <unistd.h> |
100 | #include <fcntl.h> | |
101 | #include <string.h> | |
6f9ac9f4 | 102 | #include <stdarg.h> |
1da177e4 LT |
103 | #include <stdlib.h> |
104 | #include <stdio.h> | |
1da177e4 | 105 | #include <ctype.h> |
1da177e4 | 106 | |
4356f489 | 107 | static void usage(void) |
1da177e4 | 108 | { |
bbda5ec6 | 109 | fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n"); |
1da177e4 LT |
110 | exit(1); |
111 | } | |
112 | ||
6f9ac9f4 MY |
113 | /* |
114 | * In the intended usage of this program, the stdout is redirected to .*.cmd | |
115 | * files. The return value of printf() and putchar() must be checked to catch | |
116 | * any error, e.g. "No space left on device". | |
117 | */ | |
118 | static void xprintf(const char *format, ...) | |
119 | { | |
120 | va_list ap; | |
121 | int ret; | |
122 | ||
123 | va_start(ap, format); | |
124 | ret = vprintf(format, ap); | |
125 | if (ret < 0) { | |
126 | perror("fixdep"); | |
127 | exit(1); | |
128 | } | |
129 | va_end(ap); | |
130 | } | |
131 | ||
132 | static void xputchar(int c) | |
133 | { | |
134 | int ret; | |
135 | ||
136 | ret = putchar(c); | |
137 | if (ret == EOF) { | |
138 | perror("fixdep"); | |
139 | exit(1); | |
140 | } | |
141 | } | |
142 | ||
d8329e35 NP |
143 | /* |
144 | * Print out a dependency path from a symbol name | |
145 | */ | |
fbfa9be9 | 146 | static void print_dep(const char *m, int slen, const char *dir) |
d8329e35 | 147 | { |
b3aa58d2 | 148 | int c, prev_c = '/', i; |
d8329e35 | 149 | |
6f9ac9f4 | 150 | xprintf(" $(wildcard %s/", dir); |
d8329e35 NP |
151 | for (i = 0; i < slen; i++) { |
152 | c = m[i]; | |
153 | if (c == '_') | |
154 | c = '/'; | |
155 | else | |
156 | c = tolower(c); | |
b3aa58d2 | 157 | if (c != '/' || prev_c != '/') |
6f9ac9f4 | 158 | xputchar(c); |
b3aa58d2 | 159 | prev_c = c; |
d8329e35 | 160 | } |
6f9ac9f4 | 161 | xprintf(".h) \\\n"); |
d8329e35 NP |
162 | } |
163 | ||
8af27e1d ED |
164 | struct item { |
165 | struct item *next; | |
166 | unsigned int len; | |
167 | unsigned int hash; | |
168 | char name[0]; | |
169 | }; | |
1da177e4 | 170 | |
8af27e1d ED |
171 | #define HASHSZ 256 |
172 | static struct item *hashtab[HASHSZ]; | |
1da177e4 | 173 | |
8af27e1d ED |
174 | static unsigned int strhash(const char *str, unsigned int sz) |
175 | { | |
176 | /* fnv32 hash */ | |
177 | unsigned int i, hash = 2166136261U; | |
1da177e4 | 178 | |
8af27e1d ED |
179 | for (i = 0; i < sz; i++) |
180 | hash = (hash ^ str[i]) * 0x01000193; | |
181 | return hash; | |
182 | } | |
1da177e4 LT |
183 | |
184 | /* | |
185 | * Lookup a value in the configuration string. | |
186 | */ | |
8af27e1d | 187 | static int is_defined_config(const char *name, int len, unsigned int hash) |
1da177e4 | 188 | { |
8af27e1d ED |
189 | struct item *aux; |
190 | ||
191 | for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) { | |
192 | if (aux->hash == hash && aux->len == len && | |
193 | memcmp(aux->name, name, len) == 0) | |
1da177e4 LT |
194 | return 1; |
195 | } | |
196 | return 0; | |
197 | } | |
198 | ||
199 | /* | |
200 | * Add a new value to the configuration string. | |
201 | */ | |
8af27e1d | 202 | static void define_config(const char *name, int len, unsigned int hash) |
1da177e4 | 203 | { |
8af27e1d | 204 | struct item *aux = malloc(sizeof(*aux) + len); |
1da177e4 | 205 | |
8af27e1d ED |
206 | if (!aux) { |
207 | perror("fixdep:malloc"); | |
208 | exit(1); | |
209 | } | |
210 | memcpy(aux->name, name, len); | |
211 | aux->len = len; | |
212 | aux->hash = hash; | |
213 | aux->next = hashtab[hash % HASHSZ]; | |
214 | hashtab[hash % HASHSZ] = aux; | |
1da177e4 LT |
215 | } |
216 | ||
1da177e4 LT |
217 | /* |
218 | * Record the use of a CONFIG_* word. | |
219 | */ | |
8af27e1d | 220 | static void use_config(const char *m, int slen) |
1da177e4 | 221 | { |
8af27e1d | 222 | unsigned int hash = strhash(m, slen); |
1da177e4 | 223 | |
8af27e1d | 224 | if (is_defined_config(m, slen, hash)) |
1da177e4 LT |
225 | return; |
226 | ||
8af27e1d | 227 | define_config(m, slen, hash); |
fbfa9be9 | 228 | print_dep(m, slen, "include/config"); |
1da177e4 LT |
229 | } |
230 | ||
ab9ce9fe MY |
231 | /* test if s ends in sub */ |
232 | static int str_ends_with(const char *s, int slen, const char *sub) | |
233 | { | |
234 | int sublen = strlen(sub); | |
235 | ||
236 | if (sublen > slen) | |
237 | return 0; | |
238 | ||
239 | return !memcmp(s + slen - sublen, sub, sublen); | |
240 | } | |
241 | ||
dee81e98 | 242 | static void parse_config_file(const char *p) |
1da177e4 | 243 | { |
dee81e98 | 244 | const char *q, *r; |
5b8ad96d | 245 | const char *start = p; |
dee81e98 AD |
246 | |
247 | while ((p = strstr(p, "CONFIG_"))) { | |
5b8ad96d RV |
248 | if (p > start && (isalnum(p[-1]) || p[-1] == '_')) { |
249 | p += 7; | |
250 | continue; | |
251 | } | |
d7211096 | 252 | p += 7; |
dee81e98 AD |
253 | q = p; |
254 | while (*q && (isalnum(*q) || *q == '_')) | |
255 | q++; | |
ab9ce9fe | 256 | if (str_ends_with(p, q - p, "_MODULE")) |
dee81e98 AD |
257 | r = q - 7; |
258 | else | |
259 | r = q; | |
260 | if (r > p) | |
261 | use_config(p, r - p); | |
262 | p = q; | |
1da177e4 LT |
263 | } |
264 | } | |
265 | ||
4003fd80 | 266 | static void *read_file(const char *filename) |
1da177e4 LT |
267 | { |
268 | struct stat st; | |
269 | int fd; | |
4003fd80 | 270 | char *buf; |
1da177e4 LT |
271 | |
272 | fd = open(filename, O_RDONLY); | |
273 | if (fd < 0) { | |
4003fd80 | 274 | fprintf(stderr, "fixdep: error opening file: "); |
1da177e4 LT |
275 | perror(filename); |
276 | exit(2); | |
277 | } | |
46fe94ad | 278 | if (fstat(fd, &st) < 0) { |
4003fd80 | 279 | fprintf(stderr, "fixdep: error fstat'ing file: "); |
46fe94ad TR |
280 | perror(filename); |
281 | exit(2); | |
282 | } | |
4003fd80 MY |
283 | buf = malloc(st.st_size + 1); |
284 | if (!buf) { | |
dee81e98 | 285 | perror("fixdep: malloc"); |
7c2ec43a | 286 | exit(2); |
1da177e4 | 287 | } |
4003fd80 | 288 | if (read(fd, buf, st.st_size) != st.st_size) { |
dee81e98 | 289 | perror("fixdep: read"); |
7c2ec43a | 290 | exit(2); |
dee81e98 | 291 | } |
4003fd80 | 292 | buf[st.st_size] = '\0'; |
dee81e98 | 293 | close(fd); |
1da177e4 | 294 | |
4003fd80 | 295 | return buf; |
1da177e4 LT |
296 | } |
297 | ||
87b95a81 MY |
298 | /* Ignore certain dependencies */ |
299 | static int is_ignored_file(const char *s, int len) | |
300 | { | |
301 | return str_ends_with(s, len, "include/generated/autoconf.h") || | |
302 | str_ends_with(s, len, "include/generated/autoksyms.h") || | |
87b95a81 MY |
303 | str_ends_with(s, len, ".ver"); |
304 | } | |
305 | ||
7840fea2 MM |
306 | /* |
307 | * Important: The below generated source_foo.o and deps_foo.o variable | |
308 | * assignments are parsed not only by make, but also by the rather simple | |
309 | * parser in scripts/mod/sumversion.c. | |
310 | */ | |
bbda5ec6 | 311 | static void parse_dep_file(char *m, const char *target) |
1da177e4 | 312 | { |
48b9d03c | 313 | char *p; |
01b5cbe7 | 314 | int is_last, is_target; |
2ab8a996 SW |
315 | int saw_any_target = 0; |
316 | int is_first_dep = 0; | |
4003fd80 | 317 | void *buf; |
1da177e4 | 318 | |
01b5cbe7 | 319 | while (1) { |
2ab8a996 | 320 | /* Skip any "white space" */ |
01b5cbe7 | 321 | while (*m == ' ' || *m == '\\' || *m == '\n') |
1da177e4 | 322 | m++; |
01b5cbe7 MY |
323 | |
324 | if (!*m) | |
325 | break; | |
326 | ||
2ab8a996 | 327 | /* Find next "white space" */ |
1da177e4 | 328 | p = m; |
01b5cbe7 | 329 | while (*p && *p != ' ' && *p != '\\' && *p != '\n') |
1da177e4 | 330 | p++; |
01b5cbe7 | 331 | is_last = (*p == '\0'); |
2ab8a996 SW |
332 | /* Is the token we found a target name? */ |
333 | is_target = (*(p-1) == ':'); | |
334 | /* Don't write any target names into the dependency file */ | |
335 | if (is_target) { | |
336 | /* The /next/ file is the first dependency */ | |
337 | is_first_dep = 1; | |
87b95a81 | 338 | } else if (!is_ignored_file(m, p - m)) { |
ccfe7887 | 339 | *p = '\0'; |
2ab8a996 | 340 | |
87b95a81 MY |
341 | /* |
342 | * Do not list the source file as dependency, so that | |
343 | * kbuild is not confused if a .c file is rewritten | |
344 | * into .S or vice versa. Storing it in source_* is | |
345 | * needed for modpost to compute srcversions. | |
346 | */ | |
347 | if (is_first_dep) { | |
2ab8a996 | 348 | /* |
87b95a81 MY |
349 | * If processing the concatenation of multiple |
350 | * dependency files, only process the first | |
351 | * target name, which will be the original | |
352 | * source name, and ignore any other target | |
353 | * names, which will be intermediate temporary | |
354 | * files. | |
2ab8a996 | 355 | */ |
87b95a81 MY |
356 | if (!saw_any_target) { |
357 | saw_any_target = 1; | |
6f9ac9f4 MY |
358 | xprintf("source_%s := %s\n\n", |
359 | target, m); | |
360 | xprintf("deps_%s := \\\n", target); | |
87b95a81 MY |
361 | } |
362 | is_first_dep = 0; | |
363 | } else { | |
6f9ac9f4 | 364 | xprintf(" %s \\\n", m); |
2ab8a996 | 365 | } |
87b95a81 MY |
366 | |
367 | buf = read_file(m); | |
368 | parse_config_file(buf); | |
369 | free(buf); | |
1da177e4 | 370 | } |
01b5cbe7 MY |
371 | |
372 | if (is_last) | |
373 | break; | |
374 | ||
2ab8a996 SW |
375 | /* |
376 | * Start searching for next token immediately after the first | |
377 | * "whitespace" character that follows this token. | |
378 | */ | |
1da177e4 LT |
379 | m = p + 1; |
380 | } | |
2ab8a996 SW |
381 | |
382 | if (!saw_any_target) { | |
383 | fprintf(stderr, "fixdep: parse error; no targets found\n"); | |
384 | exit(1); | |
385 | } | |
386 | ||
6f9ac9f4 MY |
387 | xprintf("\n%s: $(deps_%s)\n\n", target, target); |
388 | xprintf("$(deps_%s):\n", target); | |
1da177e4 LT |
389 | } |
390 | ||
1da177e4 LT |
391 | int main(int argc, char *argv[]) |
392 | { | |
5d1ef76f | 393 | const char *depfile, *target, *cmdline; |
4003fd80 MY |
394 | void *buf; |
395 | ||
bbda5ec6 | 396 | if (argc != 4) |
1da177e4 LT |
397 | usage(); |
398 | ||
399 | depfile = argv[1]; | |
400 | target = argv[2]; | |
401 | cmdline = argv[3]; | |
402 | ||
6f9ac9f4 | 403 | xprintf("cmd_%s := %s\n\n", target, cmdline); |
4003fd80 MY |
404 | |
405 | buf = read_file(depfile); | |
bbda5ec6 | 406 | parse_dep_file(buf, target); |
4003fd80 | 407 | free(buf); |
1da177e4 LT |
408 | |
409 | return 0; | |
410 | } |