xref: /openbmc/u-boot/scripts/basic/fixdep.c (revision 002e9108)
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 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: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
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 int is_spl_build = 0; /* hack for U-Boot */
127 
usage(void)128 static void usage(void)
129 {
130 	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
131 	exit(1);
132 }
133 
134 /*
135  * Print out the commandline prefixed with cmd_<target filename> :=
136  */
print_cmdline(void)137 static void print_cmdline(void)
138 {
139 	printf("cmd_%s := %s\n\n", target, cmdline);
140 }
141 
142 struct item {
143 	struct item	*next;
144 	unsigned int	len;
145 	unsigned int	hash;
146 	char		name[0];
147 };
148 
149 #define HASHSZ 256
150 static struct item *hashtab[HASHSZ];
151 
strhash(const char * str,unsigned int sz)152 static unsigned int strhash(const char *str, unsigned int sz)
153 {
154 	/* fnv32 hash */
155 	unsigned int i, hash = 2166136261U;
156 
157 	for (i = 0; i < sz; i++)
158 		hash = (hash ^ str[i]) * 0x01000193;
159 	return hash;
160 }
161 
162 /*
163  * Lookup a value in the configuration string.
164  */
is_defined_config(const char * name,int len,unsigned int hash)165 static int is_defined_config(const char *name, int len, unsigned int hash)
166 {
167 	struct item *aux;
168 
169 	for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
170 		if (aux->hash == hash && aux->len == len &&
171 		    memcmp(aux->name, name, len) == 0)
172 			return 1;
173 	}
174 	return 0;
175 }
176 
177 /*
178  * Add a new value to the configuration string.
179  */
define_config(const char * name,int len,unsigned int hash)180 static void define_config(const char *name, int len, unsigned int hash)
181 {
182 	struct item *aux = malloc(sizeof(*aux) + len);
183 
184 	if (!aux) {
185 		perror("fixdep:malloc");
186 		exit(1);
187 	}
188 	memcpy(aux->name, name, len);
189 	aux->len = len;
190 	aux->hash = hash;
191 	aux->next = hashtab[hash % HASHSZ];
192 	hashtab[hash % HASHSZ] = aux;
193 }
194 
195 /*
196  * Record the use of a CONFIG_* word.
197  */
use_config(const char * m,int slen)198 static void use_config(const char *m, int slen)
199 {
200 	unsigned int hash = strhash(m, slen);
201 	int c, i;
202 
203 	if (is_defined_config(m, slen, hash))
204 	    return;
205 
206 	define_config(m, slen, hash);
207 
208 	printf("    $(wildcard include/config/");
209 	for (i = 0; i < slen; i++) {
210 		c = m[i];
211 		if (c == '_')
212 			c = '/';
213 		else
214 			c = tolower(c);
215 		putchar(c);
216 	}
217 	printf(".h) \\\n");
218 }
219 
parse_config_file(const char * map,size_t len)220 static void parse_config_file(const char *map, size_t len)
221 {
222 	const int *end = (const int *) (map + len);
223 	/* start at +1, so that p can never be < map */
224 	const int *m   = (const int *) map + 1;
225 	const char *p, *q;
226 	char tmp_buf[256] = "SPL_"; /* hack for U-Boot */
227 
228 	for (; m < end; m++) {
229 		if (*m == INT_CONF) { p = (char *) m  ; goto conf; }
230 		if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
231 		if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
232 		if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
233 		continue;
234 	conf:
235 		if (p > map + len - 7)
236 			continue;
237 		if (memcmp(p, "CONFIG_", 7))
238 			continue;
239 		p += 7;
240 		for (q = p; q < map + len; q++) {
241 			if (!(isalnum(*q) || *q == '_'))
242 				goto found;
243 		}
244 		continue;
245 
246 	found:
247 		if (!memcmp(q - 7, "_MODULE", 7))
248 			q -= 7;
249 		if (q - p < 0)
250 			continue;
251 
252 		/*
253 		 * U-Boot also handles
254 		 *   CONFIG_IS_ENABLED(...)
255 		 *   CONFIG_IS_BUILTIN(...)
256 		 *   CONFIG_IS_MODULE(...)
257 		 *   CONFIG_VAL(...)
258 		 */
259 		if ((q - p == 10 && !memcmp(p, "IS_ENABLED(", 11)) ||
260 		    (q - p == 10 && !memcmp(p, "IS_BUILTIN(", 11)) ||
261 		    (q - p == 9 && !memcmp(p, "IS_MODULE(", 10)) ||
262 		    (q - p == 3 && !memcmp(p, "VAL(", 4))) {
263 			p = q + 1;
264 			for (q = p; q < map + len; q++)
265 				if (*q == ')')
266 					goto found2;
267 			continue;
268 
269 		found2:
270 			if (is_spl_build) {
271 				memcpy(tmp_buf + 4, p, q - p);
272 				q = tmp_buf + 4 + (q - p);
273 				p = tmp_buf;
274 			}
275 		}
276 		/* end U-Boot hack */
277 
278 		use_config(p, q - p);
279 	}
280 }
281 
282 /* test is s ends in sub */
strrcmp(char * s,char * sub)283 static int strrcmp(char *s, char *sub)
284 {
285 	int slen = strlen(s);
286 	int sublen = strlen(sub);
287 
288 	if (sublen > slen)
289 		return 1;
290 
291 	return memcmp(s + slen - sublen, sub, sublen);
292 }
293 
do_config_file(const char * filename)294 static void do_config_file(const char *filename)
295 {
296 	struct stat st;
297 	int fd;
298 	void *map;
299 
300 	fd = open(filename, O_RDONLY);
301 	if (fd < 0) {
302 		fprintf(stderr, "fixdep: error opening config file: ");
303 		perror(filename);
304 		exit(2);
305 	}
306 	if (fstat(fd, &st) < 0) {
307 		fprintf(stderr, "fixdep: error fstat'ing config file: ");
308 		perror(filename);
309 		exit(2);
310 	}
311 	if (st.st_size == 0) {
312 		close(fd);
313 		return;
314 	}
315 	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
316 	if ((long) map == -1) {
317 		perror("fixdep: mmap");
318 		close(fd);
319 		return;
320 	}
321 
322 	parse_config_file(map, st.st_size);
323 
324 	munmap(map, st.st_size);
325 
326 	close(fd);
327 }
328 
329 /*
330  * Important: The below generated source_foo.o and deps_foo.o variable
331  * assignments are parsed not only by make, but also by the rather simple
332  * parser in scripts/mod/sumversion.c.
333  */
parse_dep_file(void * map,size_t len)334 static void parse_dep_file(void *map, size_t len)
335 {
336 	char *m = map;
337 	char *end = m + len;
338 	char *p;
339 	char s[PATH_MAX];
340 	int is_target;
341 	int saw_any_target = 0;
342 	int is_first_dep = 0;
343 
344 	while (m < end) {
345 		/* Skip any "white space" */
346 		while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
347 			m++;
348 		/* Find next "white space" */
349 		p = m;
350 		while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
351 			p++;
352 		/* Is the token we found a target name? */
353 		is_target = (*(p-1) == ':');
354 		/* Don't write any target names into the dependency file */
355 		if (is_target) {
356 			/* The /next/ file is the first dependency */
357 			is_first_dep = 1;
358 		} else {
359 			/* Save this token/filename */
360 			memcpy(s, m, p-m);
361 			s[p - m] = 0;
362 
363 			/* Ignore certain dependencies */
364 			if (strrcmp(s, "include/generated/autoconf.h") &&
365 			    strrcmp(s, "arch/um/include/uml-config.h") &&
366 			    strrcmp(s, "include/linux/kconfig.h") &&
367 			    strrcmp(s, ".ver")) {
368 				/*
369 				 * Do not list the source file as dependency,
370 				 * so that kbuild is not confused if a .c file
371 				 * is rewritten into .S or vice versa. Storing
372 				 * it in source_* is needed for modpost to
373 				 * compute srcversions.
374 				 */
375 				if (is_first_dep) {
376 					/*
377 					 * If processing the concatenation of
378 					 * multiple dependency files, only
379 					 * process the first target name, which
380 					 * will be the original source name,
381 					 * and ignore any other target names,
382 					 * which will be intermediate temporary
383 					 * files.
384 					 */
385 					if (!saw_any_target) {
386 						saw_any_target = 1;
387 						printf("source_%s := %s\n\n",
388 							target, s);
389 						printf("deps_%s := \\\n",
390 							target);
391 					}
392 					is_first_dep = 0;
393 				} else
394 					printf("  %s \\\n", s);
395 				do_config_file(s);
396 			}
397 		}
398 		/*
399 		 * Start searching for next token immediately after the first
400 		 * "whitespace" character that follows this token.
401 		 */
402 		m = p + 1;
403 	}
404 
405 	if (!saw_any_target) {
406 		fprintf(stderr, "fixdep: parse error; no targets found\n");
407 		exit(1);
408 	}
409 
410 	printf("\n%s: $(deps_%s)\n\n", target, target);
411 	printf("$(deps_%s):\n", target);
412 }
413 
print_deps(void)414 static void print_deps(void)
415 {
416 	struct stat st;
417 	int fd;
418 	void *map;
419 
420 	fd = open(depfile, O_RDONLY);
421 	if (fd < 0) {
422 		fprintf(stderr, "fixdep: error opening depfile: ");
423 		perror(depfile);
424 		exit(2);
425 	}
426 	if (fstat(fd, &st) < 0) {
427 		fprintf(stderr, "fixdep: error fstat'ing depfile: ");
428 		perror(depfile);
429 		exit(2);
430 	}
431 	if (st.st_size == 0) {
432 		fprintf(stderr,"fixdep: %s is empty\n",depfile);
433 		close(fd);
434 		return;
435 	}
436 	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
437 	if ((long) map == -1) {
438 		perror("fixdep: mmap");
439 		close(fd);
440 		return;
441 	}
442 
443 	parse_dep_file(map, st.st_size);
444 
445 	munmap(map, st.st_size);
446 
447 	close(fd);
448 }
449 
traps(void)450 static void traps(void)
451 {
452 	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
453 	int *p = (int *)test;
454 
455 	if (*p != INT_CONF) {
456 		fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianness? %#x\n",
457 			*p);
458 		exit(2);
459 	}
460 }
461 
main(int argc,char * argv[])462 int main(int argc, char *argv[])
463 {
464 	traps();
465 
466 	if (argc != 4)
467 		usage();
468 
469 	depfile = argv[1];
470 	target = argv[2];
471 	cmdline = argv[3];
472 
473 	/* hack for U-Boot */
474 	if (!strncmp(target, "spl/", 4) || !strncmp(target, "tpl/", 4))
475 		is_spl_build = 1;
476 
477 	print_cmdline();
478 	print_deps();
479 
480 	return 0;
481 }
482