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 | |
0e0345b7 | 37 | * which depend on "include/config/HIS_DRIVER" 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 |
0e0345b7 | 77 | * dependencies on include/config/MY_OPTION for every |
4e433fc4 | 78 | * CONFIG_MY_OPTION encountered in any of the prerequisites. |
1da177e4 | 79 | * |
dee81e98 | 80 | * We don't even try to really parse the header files, but |
1da177e4 LT |
81 | * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will |
82 | * be picked up as well. It's not a problem with respect to | |
83 | * correctness, since that can only give too many dependencies, thus | |
84 | * we cannot miss a rebuild. Since people tend to not mention totally | |
85 | * unrelated CONFIG_ options all over the place, it's not an | |
86 | * efficiency problem either. | |
87 | * | |
88 | * (Note: it'd be easy to port over the complete mkdep state machine, | |
89 | * but I don't think the added complexity is worth it) | |
90 | */ | |
1da177e4 LT |
91 | |
92 | #include <sys/types.h> | |
93 | #include <sys/stat.h> | |
1da177e4 LT |
94 | #include <unistd.h> |
95 | #include <fcntl.h> | |
96 | #include <string.h> | |
97 | #include <stdlib.h> | |
98 | #include <stdio.h> | |
1da177e4 | 99 | #include <ctype.h> |
1da177e4 | 100 | |
4356f489 | 101 | static void usage(void) |
1da177e4 | 102 | { |
bbda5ec6 | 103 | fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n"); |
1da177e4 LT |
104 | exit(1); |
105 | } | |
106 | ||
8af27e1d ED |
107 | struct item { |
108 | struct item *next; | |
109 | unsigned int len; | |
110 | unsigned int hash; | |
859c8175 | 111 | char name[]; |
8af27e1d | 112 | }; |
1da177e4 | 113 | |
8af27e1d ED |
114 | #define HASHSZ 256 |
115 | static struct item *hashtab[HASHSZ]; | |
1da177e4 | 116 | |
8af27e1d ED |
117 | static unsigned int strhash(const char *str, unsigned int sz) |
118 | { | |
119 | /* fnv32 hash */ | |
120 | unsigned int i, hash = 2166136261U; | |
1da177e4 | 121 | |
8af27e1d ED |
122 | for (i = 0; i < sz; i++) |
123 | hash = (hash ^ str[i]) * 0x01000193; | |
124 | return hash; | |
125 | } | |
1da177e4 LT |
126 | |
127 | /* | |
128 | * Lookup a value in the configuration string. | |
129 | */ | |
8af27e1d | 130 | static int is_defined_config(const char *name, int len, unsigned int hash) |
1da177e4 | 131 | { |
8af27e1d ED |
132 | struct item *aux; |
133 | ||
134 | for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) { | |
135 | if (aux->hash == hash && aux->len == len && | |
136 | memcmp(aux->name, name, len) == 0) | |
1da177e4 LT |
137 | return 1; |
138 | } | |
139 | return 0; | |
140 | } | |
141 | ||
142 | /* | |
143 | * Add a new value to the configuration string. | |
144 | */ | |
8af27e1d | 145 | static void define_config(const char *name, int len, unsigned int hash) |
1da177e4 | 146 | { |
8af27e1d | 147 | struct item *aux = malloc(sizeof(*aux) + len); |
1da177e4 | 148 | |
8af27e1d ED |
149 | if (!aux) { |
150 | perror("fixdep:malloc"); | |
151 | exit(1); | |
152 | } | |
153 | memcpy(aux->name, name, len); | |
154 | aux->len = len; | |
155 | aux->hash = hash; | |
156 | aux->next = hashtab[hash % HASHSZ]; | |
157 | hashtab[hash % HASHSZ] = aux; | |
1da177e4 LT |
158 | } |
159 | ||
1da177e4 LT |
160 | /* |
161 | * Record the use of a CONFIG_* word. | |
162 | */ | |
8af27e1d | 163 | static void use_config(const char *m, int slen) |
1da177e4 | 164 | { |
8af27e1d | 165 | unsigned int hash = strhash(m, slen); |
1da177e4 | 166 | |
8af27e1d | 167 | if (is_defined_config(m, slen, hash)) |
1da177e4 LT |
168 | return; |
169 | ||
8af27e1d | 170 | define_config(m, slen, hash); |
0e0345b7 | 171 | /* Print out a dependency path from a symbol name. */ |
69304379 | 172 | printf(" $(wildcard include/config/%.*s) \\\n", slen, m); |
1da177e4 LT |
173 | } |
174 | ||
ab9ce9fe MY |
175 | /* test if s ends in sub */ |
176 | static int str_ends_with(const char *s, int slen, const char *sub) | |
177 | { | |
178 | int sublen = strlen(sub); | |
179 | ||
180 | if (sublen > slen) | |
181 | return 0; | |
182 | ||
183 | return !memcmp(s + slen - sublen, sub, sublen); | |
184 | } | |
185 | ||
dee81e98 | 186 | static void parse_config_file(const char *p) |
1da177e4 | 187 | { |
dee81e98 | 188 | const char *q, *r; |
5b8ad96d | 189 | const char *start = p; |
dee81e98 AD |
190 | |
191 | while ((p = strstr(p, "CONFIG_"))) { | |
5b8ad96d RV |
192 | if (p > start && (isalnum(p[-1]) || p[-1] == '_')) { |
193 | p += 7; | |
194 | continue; | |
195 | } | |
d7211096 | 196 | p += 7; |
dee81e98 | 197 | q = p; |
3f9070a6 | 198 | while (isalnum(*q) || *q == '_') |
dee81e98 | 199 | q++; |
ab9ce9fe | 200 | if (str_ends_with(p, q - p, "_MODULE")) |
dee81e98 AD |
201 | r = q - 7; |
202 | else | |
203 | r = q; | |
204 | if (r > p) | |
205 | use_config(p, r - p); | |
206 | p = q; | |
1da177e4 LT |
207 | } |
208 | } | |
209 | ||
4003fd80 | 210 | static void *read_file(const char *filename) |
1da177e4 LT |
211 | { |
212 | struct stat st; | |
213 | int fd; | |
4003fd80 | 214 | char *buf; |
1da177e4 LT |
215 | |
216 | fd = open(filename, O_RDONLY); | |
217 | if (fd < 0) { | |
4003fd80 | 218 | fprintf(stderr, "fixdep: error opening file: "); |
1da177e4 LT |
219 | perror(filename); |
220 | exit(2); | |
221 | } | |
46fe94ad | 222 | if (fstat(fd, &st) < 0) { |
4003fd80 | 223 | fprintf(stderr, "fixdep: error fstat'ing file: "); |
46fe94ad TR |
224 | perror(filename); |
225 | exit(2); | |
226 | } | |
4003fd80 MY |
227 | buf = malloc(st.st_size + 1); |
228 | if (!buf) { | |
dee81e98 | 229 | perror("fixdep: malloc"); |
7c2ec43a | 230 | exit(2); |
1da177e4 | 231 | } |
4003fd80 | 232 | if (read(fd, buf, st.st_size) != st.st_size) { |
dee81e98 | 233 | perror("fixdep: read"); |
7c2ec43a | 234 | exit(2); |
dee81e98 | 235 | } |
4003fd80 | 236 | buf[st.st_size] = '\0'; |
dee81e98 | 237 | close(fd); |
1da177e4 | 238 | |
4003fd80 | 239 | return buf; |
1da177e4 LT |
240 | } |
241 | ||
87b95a81 MY |
242 | /* Ignore certain dependencies */ |
243 | static int is_ignored_file(const char *s, int len) | |
244 | { | |
245 | return str_ends_with(s, len, "include/generated/autoconf.h") || | |
87d660f0 | 246 | str_ends_with(s, len, "include/generated/autoksyms.h"); |
87b95a81 MY |
247 | } |
248 | ||
7840fea2 MM |
249 | /* |
250 | * Important: The below generated source_foo.o and deps_foo.o variable | |
251 | * assignments are parsed not only by make, but also by the rather simple | |
252 | * parser in scripts/mod/sumversion.c. | |
253 | */ | |
bbda5ec6 | 254 | static void parse_dep_file(char *m, const char *target) |
1da177e4 | 255 | { |
48b9d03c | 256 | char *p; |
01b5cbe7 | 257 | int is_last, is_target; |
2ab8a996 SW |
258 | int saw_any_target = 0; |
259 | int is_first_dep = 0; | |
4003fd80 | 260 | void *buf; |
1da177e4 | 261 | |
01b5cbe7 | 262 | while (1) { |
2ab8a996 | 263 | /* Skip any "white space" */ |
01b5cbe7 | 264 | while (*m == ' ' || *m == '\\' || *m == '\n') |
1da177e4 | 265 | m++; |
01b5cbe7 MY |
266 | |
267 | if (!*m) | |
268 | break; | |
269 | ||
2ab8a996 | 270 | /* Find next "white space" */ |
1da177e4 | 271 | p = m; |
01b5cbe7 | 272 | while (*p && *p != ' ' && *p != '\\' && *p != '\n') |
1da177e4 | 273 | p++; |
01b5cbe7 | 274 | is_last = (*p == '\0'); |
2ab8a996 SW |
275 | /* Is the token we found a target name? */ |
276 | is_target = (*(p-1) == ':'); | |
277 | /* Don't write any target names into the dependency file */ | |
278 | if (is_target) { | |
279 | /* The /next/ file is the first dependency */ | |
280 | is_first_dep = 1; | |
87b95a81 | 281 | } else if (!is_ignored_file(m, p - m)) { |
ccfe7887 | 282 | *p = '\0'; |
2ab8a996 | 283 | |
87b95a81 MY |
284 | /* |
285 | * Do not list the source file as dependency, so that | |
286 | * kbuild is not confused if a .c file is rewritten | |
287 | * into .S or vice versa. Storing it in source_* is | |
288 | * needed for modpost to compute srcversions. | |
289 | */ | |
290 | if (is_first_dep) { | |
2ab8a996 | 291 | /* |
87b95a81 MY |
292 | * If processing the concatenation of multiple |
293 | * dependency files, only process the first | |
294 | * target name, which will be the original | |
295 | * source name, and ignore any other target | |
296 | * names, which will be intermediate temporary | |
297 | * files. | |
2ab8a996 | 298 | */ |
87b95a81 MY |
299 | if (!saw_any_target) { |
300 | saw_any_target = 1; | |
69304379 MY |
301 | printf("source_%s := %s\n\n", |
302 | target, m); | |
303 | printf("deps_%s := \\\n", target); | |
87b95a81 MY |
304 | } |
305 | is_first_dep = 0; | |
306 | } else { | |
69304379 | 307 | printf(" %s \\\n", m); |
2ab8a996 | 308 | } |
87b95a81 MY |
309 | |
310 | buf = read_file(m); | |
311 | parse_config_file(buf); | |
312 | free(buf); | |
1da177e4 | 313 | } |
01b5cbe7 MY |
314 | |
315 | if (is_last) | |
316 | break; | |
317 | ||
2ab8a996 SW |
318 | /* |
319 | * Start searching for next token immediately after the first | |
320 | * "whitespace" character that follows this token. | |
321 | */ | |
1da177e4 LT |
322 | m = p + 1; |
323 | } | |
2ab8a996 SW |
324 | |
325 | if (!saw_any_target) { | |
326 | fprintf(stderr, "fixdep: parse error; no targets found\n"); | |
327 | exit(1); | |
328 | } | |
329 | ||
69304379 MY |
330 | printf("\n%s: $(deps_%s)\n\n", target, target); |
331 | printf("$(deps_%s):\n", target); | |
1da177e4 LT |
332 | } |
333 | ||
1da177e4 LT |
334 | int main(int argc, char *argv[]) |
335 | { | |
5d1ef76f | 336 | const char *depfile, *target, *cmdline; |
4003fd80 MY |
337 | void *buf; |
338 | ||
bbda5ec6 | 339 | if (argc != 4) |
1da177e4 LT |
340 | usage(); |
341 | ||
342 | depfile = argv[1]; | |
343 | target = argv[2]; | |
344 | cmdline = argv[3]; | |
345 | ||
69304379 | 346 | printf("cmd_%s := %s\n\n", target, cmdline); |
4003fd80 MY |
347 | |
348 | buf = read_file(depfile); | |
bbda5ec6 | 349 | parse_dep_file(buf, target); |
4003fd80 | 350 | free(buf); |
1da177e4 | 351 | |
69304379 MY |
352 | fflush(stdout); |
353 | ||
354 | /* | |
355 | * In the intended usage, the stdout is redirected to .*.cmd files. | |
356 | * Call ferror() to catch errors such as "No space left on device". | |
357 | */ | |
358 | if (ferror(stdout)) { | |
359 | fprintf(stderr, "fixdep: not all data was written to the output\n"); | |
360 | exit(1); | |
361 | } | |
362 | ||
1da177e4 LT |
363 | return 0; |
364 | } |