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