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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 | |
19 | * every file in the kernel includes <linux/config.h> which then again | |
20 | * includes <linux/autoconf.h> | |
21 | * | |
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. | |
26 | * | |
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. | |
30 | * | |
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. | |
34 | * | |
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 ;-) | |
38 | * | |
39 | * The idea above dates, by the way, back to Michael E Chastain, AFAIK. | |
40 | * | |
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. | |
45 | * | |
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. | |
49 | * | |
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. | |
54 | * | |
55 | * This code here has been based partially based on mkdep.c, which | |
56 | * says the following about its history: | |
57 | * | |
58 | * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>. | |
59 | * This is a C version of syncdep.pl by Werner Almesberger. | |
60 | * | |
61 | * | |
62 | * It is invoked as | |
63 | * | |
64 | * fixdep <depfile> <target> <cmdline> | |
65 | * | |
66 | * and will read the dependency file <depfile> | |
67 | * | |
68 | * The transformed dependency snipped is written to stdout. | |
69 | * | |
70 | * It first generates a line | |
71 | * | |
72 | * cmd_<target> = <cmdline> | |
73 | * | |
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. | |
78 | * | |
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. | |
83 | * | |
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. | |
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 | */ | |
96 | /* | |
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. | |
103 | */ | |
104 | ||
105 | #include <sys/types.h> | |
106 | #include <sys/stat.h> | |
107 | #include <sys/mman.h> | |
108 | #include <unistd.h> | |
109 | #include <fcntl.h> | |
110 | #include <string.h> | |
111 | #include <stdlib.h> | |
112 | #include <stdio.h> | |
113 | #include <limits.h> | |
114 | #include <ctype.h> | |
115 | #include <arpa/inet.h> | |
116 | ||
117 | #define INT_CONF ntohl(0x434f4e46) | |
118 | #define INT_ONFI ntohl(0x4f4e4649) | |
119 | #define INT_NFIG ntohl(0x4e464947) | |
120 | #define INT_FIG_ ntohl(0x4649475f) | |
121 | ||
122 | char *target; | |
123 | char *depfile; | |
124 | char *cmdline; | |
125 | ||
126 | void usage(void) | |
127 | ||
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> := | |
135 | * If commandline contains '#' escape with '\' so make to not see | |
136 | * the '#' as a start-of-comment symbol | |
137 | **/ | |
1da177e4 LT |
138 | void print_cmdline(void) |
139 | { | |
4d99f93b SR |
140 | char *p = cmdline; |
141 | ||
142 | printf("cmd_%s := ", target); | |
143 | for (; *p; p++) { | |
144 | if (*p == '#') | |
145 | printf("\\"); | |
146 | printf("%c", *p); | |
147 | } | |
148 | printf("\n\n"); | |
1da177e4 LT |
149 | } |
150 | ||
151 | char * str_config = NULL; | |
152 | int size_config = 0; | |
153 | int len_config = 0; | |
154 | ||
155 | /* | |
156 | * Grow the configuration string to a desired length. | |
157 | * Usually the first growth is plenty. | |
158 | */ | |
159 | void grow_config(int len) | |
160 | { | |
161 | while (len_config + len > size_config) { | |
162 | if (size_config == 0) | |
163 | size_config = 2048; | |
164 | str_config = realloc(str_config, size_config *= 2); | |
165 | if (str_config == NULL) | |
166 | { perror("fixdep:malloc"); exit(1); } | |
167 | } | |
168 | } | |
169 | ||
170 | ||
171 | ||
172 | /* | |
173 | * Lookup a value in the configuration string. | |
174 | */ | |
175 | int is_defined_config(const char * name, int len) | |
176 | { | |
177 | const char * pconfig; | |
178 | const char * plast = str_config + len_config - len; | |
179 | for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) { | |
180 | if (pconfig[ -1] == '\n' | |
181 | && pconfig[len] == '\n' | |
182 | && !memcmp(pconfig, name, len)) | |
183 | return 1; | |
184 | } | |
185 | return 0; | |
186 | } | |
187 | ||
188 | /* | |
189 | * Add a new value to the configuration string. | |
190 | */ | |
191 | void define_config(const char * name, int len) | |
192 | { | |
193 | grow_config(len + 1); | |
194 | ||
195 | memcpy(str_config+len_config, name, len); | |
196 | len_config += len; | |
197 | str_config[len_config++] = '\n'; | |
198 | } | |
199 | ||
200 | /* | |
201 | * Clear the set of configuration strings. | |
202 | */ | |
203 | void clear_config(void) | |
204 | { | |
205 | len_config = 0; | |
206 | define_config("", 0); | |
207 | } | |
208 | ||
209 | /* | |
210 | * Record the use of a CONFIG_* word. | |
211 | */ | |
212 | void use_config(char *m, int slen) | |
213 | { | |
214 | char s[PATH_MAX]; | |
215 | char *p; | |
216 | ||
217 | if (is_defined_config(m, slen)) | |
218 | return; | |
219 | ||
220 | define_config(m, slen); | |
221 | ||
222 | memcpy(s, m, slen); s[slen] = 0; | |
223 | ||
224 | for (p = s; p < s + slen; p++) { | |
225 | if (*p == '_') | |
226 | *p = '/'; | |
227 | else | |
48b9d03c | 228 | *p = tolower((int)*p); |
1da177e4 LT |
229 | } |
230 | printf(" $(wildcard include/config/%s.h) \\\n", s); | |
231 | } | |
232 | ||
48b9d03c | 233 | void parse_config_file(char *map, size_t len) |
1da177e4 LT |
234 | { |
235 | int *end = (int *) (map + len); | |
236 | /* start at +1, so that p can never be < map */ | |
237 | int *m = (int *) map + 1; | |
48b9d03c | 238 | char *p, *q; |
1da177e4 LT |
239 | |
240 | for (; m < end; m++) { | |
48b9d03c M |
241 | if (*m == INT_CONF) { p = (char *) m ; goto conf; } |
242 | if (*m == INT_ONFI) { p = (char *) m-1; goto conf; } | |
243 | if (*m == INT_NFIG) { p = (char *) m-2; goto conf; } | |
244 | if (*m == INT_FIG_) { p = (char *) m-3; goto conf; } | |
1da177e4 LT |
245 | continue; |
246 | conf: | |
247 | if (p > map + len - 7) | |
248 | continue; | |
249 | if (memcmp(p, "CONFIG_", 7)) | |
250 | continue; | |
251 | for (q = p + 7; q < map + len; q++) { | |
252 | if (!(isalnum(*q) || *q == '_')) | |
253 | goto found; | |
254 | } | |
255 | continue; | |
256 | ||
257 | found: | |
258 | use_config(p+7, q-p-7); | |
259 | } | |
260 | } | |
261 | ||
262 | /* test is s ends in sub */ | |
263 | int strrcmp(char *s, char *sub) | |
264 | { | |
265 | int slen = strlen(s); | |
266 | int sublen = strlen(sub); | |
267 | ||
268 | if (sublen > slen) | |
269 | return 1; | |
270 | ||
271 | return memcmp(s + slen - sublen, sub, sublen); | |
272 | } | |
273 | ||
274 | void do_config_file(char *filename) | |
275 | { | |
276 | struct stat st; | |
277 | int fd; | |
278 | void *map; | |
279 | ||
280 | fd = open(filename, O_RDONLY); | |
281 | if (fd < 0) { | |
282 | fprintf(stderr, "fixdep: "); | |
283 | perror(filename); | |
284 | exit(2); | |
285 | } | |
286 | fstat(fd, &st); | |
287 | if (st.st_size == 0) { | |
288 | close(fd); | |
289 | return; | |
290 | } | |
291 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
292 | if ((long) map == -1) { | |
293 | perror("fixdep: mmap"); | |
294 | close(fd); | |
295 | return; | |
296 | } | |
297 | ||
298 | parse_config_file(map, st.st_size); | |
299 | ||
300 | munmap(map, st.st_size); | |
301 | ||
302 | close(fd); | |
303 | } | |
304 | ||
305 | void parse_dep_file(void *map, size_t len) | |
306 | { | |
48b9d03c M |
307 | char *m = map; |
308 | char *end = m + len; | |
309 | char *p; | |
1da177e4 LT |
310 | char s[PATH_MAX]; |
311 | ||
312 | p = strchr(m, ':'); | |
313 | if (!p) { | |
314 | fprintf(stderr, "fixdep: parse error\n"); | |
315 | exit(1); | |
316 | } | |
317 | memcpy(s, m, p-m); s[p-m] = 0; | |
318 | printf("deps_%s := \\\n", target); | |
319 | m = p+1; | |
320 | ||
321 | clear_config(); | |
322 | ||
323 | while (m < end) { | |
324 | while (m < end && (*m == ' ' || *m == '\\' || *m == '\n')) | |
325 | m++; | |
326 | p = m; | |
327 | while (p < end && *p != ' ') p++; | |
328 | if (p == end) { | |
329 | do p--; while (!isalnum(*p)); | |
330 | p++; | |
331 | } | |
332 | memcpy(s, m, p-m); s[p-m] = 0; | |
333 | if (strrcmp(s, "include/linux/autoconf.h") && | |
334 | strrcmp(s, "arch/um/include/uml-config.h") && | |
335 | strrcmp(s, ".ver")) { | |
336 | printf(" %s \\\n", s); | |
337 | do_config_file(s); | |
338 | } | |
339 | m = p + 1; | |
340 | } | |
341 | printf("\n%s: $(deps_%s)\n\n", target, target); | |
342 | printf("$(deps_%s):\n", target); | |
343 | } | |
344 | ||
345 | void print_deps(void) | |
346 | { | |
347 | struct stat st; | |
348 | int fd; | |
349 | void *map; | |
350 | ||
351 | fd = open(depfile, O_RDONLY); | |
352 | if (fd < 0) { | |
353 | fprintf(stderr, "fixdep: "); | |
354 | perror(depfile); | |
355 | exit(2); | |
356 | } | |
357 | fstat(fd, &st); | |
358 | if (st.st_size == 0) { | |
359 | fprintf(stderr,"fixdep: %s is empty\n",depfile); | |
360 | close(fd); | |
361 | return; | |
362 | } | |
363 | map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); | |
364 | if ((long) map == -1) { | |
365 | perror("fixdep: mmap"); | |
366 | close(fd); | |
367 | return; | |
368 | } | |
369 | ||
370 | parse_dep_file(map, st.st_size); | |
371 | ||
372 | munmap(map, st.st_size); | |
373 | ||
374 | close(fd); | |
375 | } | |
376 | ||
377 | void traps(void) | |
378 | { | |
379 | static char test[] __attribute__((aligned(sizeof(int)))) = "CONF"; | |
380 | ||
381 | if (*(int *)test != INT_CONF) { | |
382 | fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n", | |
383 | *(int *)test); | |
384 | exit(2); | |
385 | } | |
386 | } | |
387 | ||
388 | int main(int argc, char *argv[]) | |
389 | { | |
390 | traps(); | |
391 | ||
392 | if (argc != 4) | |
393 | usage(); | |
394 | ||
395 | depfile = argv[1]; | |
396 | target = argv[2]; | |
397 | cmdline = argv[3]; | |
398 | ||
399 | print_cmdline(); | |
400 | print_deps(); | |
401 | ||
402 | return 0; | |
403 | } |