source: branches/3.2/mindi-busybox/scripts/basic/fixdep.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 9.7 KB
Line 
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#include <alloca.h>
117
118/* bbox: not needed
119#define INT_CONF ntohl(0x434f4e46)
120#define INT_ONFI ntohl(0x4f4e4649)
121#define INT_NFIG ntohl(0x4e464947)
122#define INT_FIG_ ntohl(0x4649475f)
123*/
124
125char *target;
126char *depfile;
127char *cmdline;
128
129void usage(void)
130
131{
132    fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
133    exit(1);
134}
135
136/*
137 * Print out the commandline prefixed with cmd_<target filename> :=
138 */
139void print_cmdline(void)
140{
141    printf("cmd_%s := %s\n\n", target, cmdline);
142}
143
144char * str_config  = NULL;
145int    size_config = 0;
146int    len_config  = 0;
147
148/*
149 * Grow the configuration string to a desired length.
150 * Usually the first growth is plenty.
151 */
152void grow_config(int len)
153{
154    while (len_config + len > size_config) {
155        if (size_config == 0)
156            size_config = 2048;
157        str_config = realloc(str_config, size_config *= 2);
158        if (str_config == NULL)
159            { perror("fixdep:malloc"); exit(1); }
160    }
161}
162
163
164
165/*
166 * Lookup a value in the configuration string.
167 */
168int is_defined_config(const char * name, int len)
169{
170    const char * pconfig;
171    const char * plast = str_config + len_config - len;
172    for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {
173        if (pconfig[ -1] == '\n'
174        &&  pconfig[len] == '\n'
175        &&  !memcmp(pconfig, name, len))
176            return 1;
177    }
178    return 0;
179}
180
181/*
182 * Add a new value to the configuration string.
183 */
184void define_config(const char * name, int len)
185{
186    grow_config(len + 1);
187
188    memcpy(str_config+len_config, name, len);
189    len_config += len;
190    str_config[len_config++] = '\n';
191}
192
193/*
194 * Clear the set of configuration strings.
195 */
196void clear_config(void)
197{
198    len_config = 0;
199    define_config("", 0);
200}
201
202/*
203 * Record the use of a CONFIG_* word.
204 */
205void use_config(char *m, int slen)
206{
207    char *s = alloca(slen+1);
208    char *p;
209
210    if (is_defined_config(m, slen))
211        return;
212
213    define_config(m, slen);
214
215    memcpy(s, m, slen); s[slen] = 0;
216
217    for (p = s; p < s + slen; p++) {
218        if (*p == '_')
219            *p = '/';
220        else
221            *p = tolower((int)*p);
222    }
223    printf("    $(wildcard include/config/%s.h) \\\n", s);
224}
225
226void parse_config_file(char *map, size_t len)
227{
228    /* modified for bbox */
229    char *end_3 = map + len - 3; /* 3 == length of "IF_" */
230    char *end_7 = map + len - 7;
231    char *p = map;
232    char *q;
233    int off;
234
235    for (; p <= end_3; p++) {
236        /* Find next identifier's beginning */
237        if (!(isalnum(*p) || *p == '_'))
238            continue;
239
240        /* Check it */
241        if (p < end_7 && p[6] == '_') {
242            if (!memcmp(p, "CONFIG", 6)) goto conf7;
243            if (!memcmp(p, "ENABLE", 6)) goto conf7;
244            if (!memcmp(p, "IF_NOT", 6)) goto conf7;
245        }
246        /* we have at least 3 chars because of p <= end_3 */
247        /*if (!memcmp(p, "IF_", 3)) ...*/
248        if (p[0] == 'I' && p[1] == 'F' && p[2] == '_') {
249            off = 3;
250            goto conf;
251        }
252
253        /* This identifier is not interesting, skip it */
254        while (p <= end_3 && (isalnum(*p) || *p == '_'))
255            p++;
256        continue;
257
258    conf7:  off = 7;
259    conf:
260        p += off;
261        for (q = p; q < end_3+3; q++) {
262            if (!(isalnum(*q) || *q == '_'))
263                break;
264        }
265        if (q != p) {
266            use_config(p, q-p);
267        }
268    }
269}
270
271/* test is s ends in sub */
272int strrcmp(char *s, char *sub)
273{
274    int slen = strlen(s);
275    int sublen = strlen(sub);
276
277    if (sublen > slen)
278        return 1;
279
280    return memcmp(s + slen - sublen, sub, sublen);
281}
282
283void do_config_file(char *filename)
284{
285    struct stat st;
286    int fd;
287    void *map;
288
289    fd = open(filename, O_RDONLY);
290    if (fd < 0) {
291        fprintf(stderr, "fixdep: ");
292        perror(filename);
293        exit(2);
294    }
295    fstat(fd, &st);
296    if (st.st_size == 0) {
297        close(fd);
298        return;
299    }
300    map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
301    if ((long) map == -1) {
302        perror("fixdep: mmap");
303        close(fd);
304        return;
305    }
306
307    parse_config_file(map, st.st_size);
308
309    munmap(map, st.st_size);
310
311    close(fd);
312}
313
314void parse_dep_file(void *map, size_t len)
315{
316    char *m = map;
317    char *end = m + len;
318    char *p;
319    char *s = alloca(len);
320
321    p = memchr(m, ':', len);
322    if (!p) {
323        fprintf(stderr, "fixdep: parse error\n");
324        exit(1);
325    }
326    memcpy(s, m, p-m); s[p-m] = 0;
327    printf("deps_%s := \\\n", target);
328    m = p+1;
329
330    clear_config();
331
332    while (m < end) {
333        while (m < end && (*m == ' ' || *m == '\\' || *m == '\n' || *m == '\r'))
334            m++;
335        p = m;
336        while (p < end && *p != ' ') p++;
337        if (p == end) {
338            do p--; while (!isalnum(*p));
339            p++;
340        }
341        memcpy(s, m, p-m); s[p-m] = 0;
342        if (strrcmp(s, "include/autoconf.h") &&
343            strrcmp(s, "arch/um/include/uml-config.h") &&
344            strrcmp(s, ".ver")) {
345            printf("  %s \\\n", s);
346            do_config_file(s);
347        }
348        m = p + 1;
349    }
350    printf("\n%s: $(deps_%s)\n\n", target, target);
351    printf("$(deps_%s):\n", target);
352}
353
354void print_deps(void)
355{
356    struct stat st;
357    int fd;
358    void *map;
359
360    fd = open(depfile, O_RDONLY);
361    if (fd < 0) {
362        fprintf(stderr, "fixdep: ");
363        perror(depfile);
364        exit(2);
365    }
366    fstat(fd, &st);
367    if (st.st_size == 0) {
368        fprintf(stderr,"fixdep: %s is empty\n",depfile);
369        close(fd);
370        return;
371    }
372    map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
373    if ((long) map == -1) {
374        perror("fixdep: mmap");
375        close(fd);
376        return;
377    }
378
379    parse_dep_file(map, st.st_size);
380
381    munmap(map, st.st_size);
382
383    close(fd);
384}
385
386void traps(void)
387{
388/* bbox: not needed
389    static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
390
391    if (*(int *)test != INT_CONF) {
392        fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
393            *(int *)test);
394        exit(2);
395    }
396*/
397}
398
399int main(int argc, char **argv)
400{
401    traps();
402
403    if (argc != 4)
404        usage();
405
406    depfile = argv[1];
407    target = argv[2];
408    cmdline = argv[3];
409
410    print_cmdline();
411    print_deps();
412
413    return 0;
414}
Note: See TracBrowser for help on using the repository browser.