| 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 prerequisites.
|
| 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/config/HIS_DRIVER" 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 | * savedcmd_<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 for every
|
| 78 | * CONFIG_MY_OPTION encountered in any of the prerequisites.
|
| 79 | *
|
| 80 | * We don't even try to really parse the header files, but
|
| 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 |
|
| 91 |
|
| 92 | #include <sys/types.h>
|
| 93 | #include <sys/stat.h>
|
| 94 | #include <unistd.h>
|
| 95 | #include <fcntl.h>
|
| 96 | #include <string.h>
|
| 97 | #include <stdbool.h>
|
| 98 | #include <stdlib.h>
|
| 99 | #include <stdio.h>
|
| 100 | #include <ctype.h>
|
| 101 |
|
| 102 | static void usage(void)
|
| 103 | {
|
| 104 | fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
|
| 105 | exit(1);
|
| 106 | }
|
| 107 |
|
| 108 | struct item {
|
| 109 | struct item *next;
|
| 110 | unsigned int len;
|
| 111 | unsigned int hash;
|
| 112 | char name[];
|
| 113 | };
|
| 114 |
|
| 115 | #define HASHSZ 256
|
| 116 | static struct item *config_hashtab[HASHSZ], *file_hashtab[HASHSZ];
|
| 117 |
|
| 118 | static unsigned int strhash(const char *str, unsigned int sz)
|
| 119 | {
|
| 120 |
|
| 121 | unsigned int i, hash = 2166136261U;
|
| 122 |
|
| 123 | for (i = 0; i < sz; i++)
|
| 124 | hash = (hash ^ str[i]) * 0x01000193;
|
| 125 | return hash;
|
| 126 | }
|
| 127 |
|
| 128 | |
| 129 | * Add a new value to the configuration string.
|
| 130 |
|
| 131 | static void add_to_hashtable(const char *name, int len, unsigned int hash,
|
| 132 | struct item *hashtab[])
|
| 133 | {
|
| 134 | struct item *aux = malloc(sizeof(*aux) + len);
|
| 135 |
|
| 136 | if (!aux) {
|
| 137 | perror("fixdep:malloc");
|
| 138 | exit(1);
|
| 139 | }
|
| 140 | memcpy(aux->name, name, len);
|
| 141 | aux->len = len;
|
| 142 | aux->hash = hash;
|
| 143 | aux->next = hashtab[hash % HASHSZ];
|
| 144 | hashtab[hash % HASHSZ] = aux;
|
| 145 | }
|
| 146 |
|
| 147 | |
| 148 | * Lookup a string in the hash table. If found, just return true.
|
| 149 | * If not, add it to the hashtable and return false.
|
| 150 |
|
| 151 | static bool in_hashtable(const char *name, int len, struct item *hashtab[])
|
| 152 | {
|
| 153 | struct item *aux;
|
| 154 | unsigned int hash = strhash(name, len);
|
| 155 |
|
| 156 | for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
|
| 157 | if (aux->hash == hash && aux->len == len &&
|
| 158 | memcmp(aux->name, name, len) == 0)
|
| 159 | return true;
|
| 160 | }
|
| 161 |
|
| 162 | add_to_hashtable(name, len, hash, hashtab);
|
| 163 |
|
| 164 | return false;
|
| 165 | }
|
| 166 |
|
| 167 | |
| 168 | * Record the use of a CONFIG_* word.
|
| 169 |
|
| 170 | static void use_config(const char *m, int slen)
|
| 171 | {
|
| 172 | if (in_hashtable(m, slen, config_hashtab))
|
| 173 | return;
|
| 174 |
|
| 175 |
|
| 176 | printf(" $(wildcard include/config/%.*s) \\\n", slen, m);
|
| 177 | }
|
| 178 |
|
| 179 |
|
| 180 | static int str_ends_with(const char *s, int slen, const char *sub)
|
| 181 | {
|
| 182 | int sublen = strlen(sub);
|
| 183 |
|
| 184 | if (sublen > slen)
|
| 185 | return 0;
|
| 186 |
|
| 187 | return !memcmp(s + slen - sublen, sub, sublen);
|
| 188 | }
|
| 189 |
|
| 190 | static void parse_config_file(const char *p)
|
| 191 | {
|
| 192 | const char *q, *r;
|
| 193 | const char *start = p;
|
| 194 |
|
| 195 | while ((p = strstr(p, "CONFIG_"))) {
|
| 196 | if (p > start && (isalnum(p[-1]) || p[-1] == '_')) {
|
| 197 | p += 7;
|
| 198 | continue;
|
| 199 | }
|
| 200 | p += 7;
|
| 201 | q = p;
|
| 202 | while (isalnum(*q) || *q == '_')
|
| 203 | q++;
|
| 204 | if (str_ends_with(p, q - p, "_MODULE"))
|
| 205 | r = q - 7;
|
| 206 | else
|
| 207 | r = q;
|
| 208 | if (r > p)
|
| 209 | use_config(p, r - p);
|
| 210 | p = q;
|
| 211 | }
|
| 212 | }
|
| 213 |
|
| 214 | static void *read_file(const char *filename)
|
| 215 | {
|
| 216 | struct stat st;
|
| 217 | int fd;
|
| 218 | char *buf;
|
| 219 |
|
| 220 | fd = open(filename, O_RDONLY);
|
| 221 | if (fd < 0) {
|
| 222 | fprintf(stderr, "fixdep: error opening file: ");
|
| 223 | perror(filename);
|
| 224 | exit(2);
|
| 225 | }
|
| 226 | if (fstat(fd, &st) < 0) {
|
| 227 | fprintf(stderr, "fixdep: error fstat'ing file: ");
|
| 228 | perror(filename);
|
| 229 | exit(2);
|
| 230 | }
|
| 231 | buf = malloc(st.st_size + 1);
|
| 232 | if (!buf) {
|
| 233 | perror("fixdep: malloc");
|
| 234 | exit(2);
|
| 235 | }
|
| 236 | if (read(fd, buf, st.st_size) != st.st_size) {
|
| 237 | perror("fixdep: read");
|
| 238 | exit(2);
|
| 239 | }
|
| 240 | buf[st.st_size] = '\0';
|
| 241 | close(fd);
|
| 242 |
|
| 243 | return buf;
|
| 244 | }
|
| 245 |
|
| 246 |
|
| 247 | static int is_ignored_file(const char *s, int len)
|
| 248 | {
|
| 249 | return str_ends_with(s, len, "include/generated/autoconf.h");
|
| 250 | }
|
| 251 |
|
| 252 |
|
| 253 | static int is_no_parse_file(const char *s, int len)
|
| 254 | {
|
| 255 |
|
| 256 | return str_ends_with(s, len, ".rlib") ||
|
| 257 | str_ends_with(s, len, ".rmeta") ||
|
| 258 | str_ends_with(s, len, ".so");
|
| 259 | }
|
| 260 |
|
| 261 | |
| 262 | * Important: The below generated source_foo.o and deps_foo.o variable
|
| 263 | * assignments are parsed not only by make, but also by the rather simple
|
| 264 | * parser in scripts/mod/sumversion.c.
|
| 265 |
|
| 266 | static void parse_dep_file(char *p, const char *target)
|
| 267 | {
|
| 268 | bool saw_any_target = false;
|
| 269 | bool is_target = true;
|
| 270 | bool is_source = false;
|
| 271 | bool need_parse;
|
| 272 | char *q, saved_c;
|
| 273 |
|
| 274 | while (*p) {
|
| 275 |
|
| 276 | switch (*p) {
|
| 277 | case '#':
|
| 278 | |
| 279 | * skip comments.
|
| 280 | * rustc may emit comments to dep-info.
|
| 281 |
|
| 282 | p++;
|
| 283 | while (*p != '\0' && *p != '\n') {
|
| 284 | |
| 285 | * escaped newlines continue the comment across
|
| 286 | * multiple lines.
|
| 287 |
|
| 288 | if (*p == '\\')
|
| 289 | p++;
|
| 290 | p++;
|
| 291 | }
|
| 292 | continue;
|
| 293 | case ' ':
|
| 294 | case '\t':
|
| 295 |
|
| 296 | p++;
|
| 297 | continue;
|
| 298 | case '\\':
|
| 299 | |
| 300 | * backslash/newline combinations continue the
|
| 301 | * statement. Skip it just like a whitespace.
|
| 302 |
|
| 303 | if (*(p + 1) == '\n') {
|
| 304 | p += 2;
|
| 305 | continue;
|
| 306 | }
|
| 307 | break;
|
| 308 | case '\n':
|
| 309 | |
| 310 | * Makefiles use a line-based syntax, where the newline
|
| 311 | * is the end of a statement. After seeing a newline,
|
| 312 | * we expect the next token is a target.
|
| 313 |
|
| 314 | p++;
|
| 315 | is_target = true;
|
| 316 | continue;
|
| 317 | case ':':
|
| 318 | |
| 319 | * assume the first dependency after a colon as the
|
| 320 | * source file.
|
| 321 |
|
| 322 | p++;
|
| 323 | is_target = false;
|
| 324 | is_source = true;
|
| 325 | continue;
|
| 326 | }
|
| 327 |
|
| 328 |
|
| 329 | q = p;
|
| 330 | while (*q != ' ' && *q != '\t' && *q != '\n' && *q != '#' && *q != ':') {
|
| 331 | if (*q == '\\') {
|
| 332 | |
| 333 | * backslash/newline combinations work like as
|
| 334 | * a whitespace, so this is the end of token.
|
| 335 |
|
| 336 | if (*(q + 1) == '\n')
|
| 337 | break;
|
| 338 |
|
| 339 |
|
| 340 | if (*(q + 1) == '#' || *(q + 1) == ':') {
|
| 341 | memmove(p + 1, p, q - p);
|
| 342 | p++;
|
| 343 | }
|
| 344 |
|
| 345 | q++;
|
| 346 | }
|
| 347 |
|
| 348 | if (*q == '\0')
|
| 349 | break;
|
| 350 | q++;
|
| 351 | }
|
| 352 |
|
| 353 |
|
| 354 | if (is_target) {
|
| 355 | p = q;
|
| 356 | continue;
|
| 357 | }
|
| 358 |
|
| 359 | saved_c = *q;
|
| 360 | *q = '\0';
|
| 361 | need_parse = false;
|
| 362 |
|
| 363 | |
| 364 | * Do not list the source file as dependency, so that kbuild is
|
| 365 | * not confused if a .c file is rewritten into .S or vice versa.
|
| 366 | * Storing it in source_* is needed for modpost to compute
|
| 367 | * srcversions.
|
| 368 |
|
| 369 | if (is_source) {
|
| 370 | |
| 371 | * The DT build rule concatenates multiple dep files.
|
| 372 | * When processing them, only process the first source
|
| 373 | * name, which will be the original one, and ignore any
|
| 374 | * other source names, which will be intermediate
|
| 375 | * temporary files.
|
| 376 | *
|
| 377 | * rustc emits the same dependency list for each
|
| 378 | * emission type. It is enough to list the source name
|
| 379 | * just once.
|
| 380 |
|
| 381 | if (!saw_any_target) {
|
| 382 | saw_any_target = true;
|
| 383 | printf("source_%s := %s\n\n", target, p);
|
| 384 | printf("deps_%s := \\\n", target);
|
| 385 | need_parse = true;
|
| 386 | }
|
| 387 | } else if (!is_ignored_file(p, q - p) &&
|
| 388 | !in_hashtable(p, q - p, file_hashtab)) {
|
| 389 | printf(" %s \\\n", p);
|
| 390 | need_parse = true;
|
| 391 | }
|
| 392 |
|
| 393 | if (need_parse && !is_no_parse_file(p, q - p)) {
|
| 394 | void *buf;
|
| 395 |
|
| 396 | buf = read_file(p);
|
| 397 | parse_config_file(buf);
|
| 398 | free(buf);
|
| 399 | }
|
| 400 |
|
| 401 | is_source = false;
|
| 402 | *q = saved_c;
|
| 403 | p = q;
|
| 404 | }
|
| 405 |
|
| 406 | if (!saw_any_target) {
|
| 407 | fprintf(stderr, "fixdep: parse error; no targets found\n");
|
| 408 | exit(1);
|
| 409 | }
|
| 410 |
|
| 411 | printf("\n%s: $(deps_%s)\n\n", target, target);
|
| 412 | printf("$(deps_%s):\n", target);
|
| 413 | }
|
| 414 |
|
| 415 | int main(int argc, char *argv[])
|
| 416 | {
|
| 417 | const char *depfile, *target, *cmdline;
|
| 418 | void *buf;
|
| 419 |
|
| 420 | if (argc != 4)
|
| 421 | usage();
|
| 422 |
|
| 423 | depfile = argv[1];
|
| 424 | target = argv[2];
|
| 425 | cmdline = argv[3];
|
| 426 |
|
| 427 | printf("savedcmd_%s := %s\n\n", target, cmdline);
|
| 428 |
|
| 429 | buf = read_file(depfile);
|
| 430 | parse_dep_file(buf, target);
|
| 431 | free(buf);
|
| 432 |
|
| 433 | fflush(stdout);
|
| 434 |
|
| 435 | |
| 436 | * In the intended usage, the stdout is redirected to .*.cmd files.
|
| 437 | * Call ferror() to catch errors such as "No space left on device".
|
| 438 |
|
| 439 | if (ferror(stdout)) {
|
| 440 | fprintf(stderr, "fixdep: not all data was written to the output\n");
|
| 441 | exit(1);
|
| 442 | }
|
| 443 |
|
| 444 | return 0;
|
| 445 | }
|