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Diffstat (limited to 'scripts/basic/fixdep.c')
| -rw-r--r-- | scripts/basic/fixdep.c | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c new file mode 100644 index 0000000..078fe1d --- /dev/null +++ b/scripts/basic/fixdep.c @@ -0,0 +1,462 @@ +/* + * "Optimize" a list of dependencies as spit out by gcc -MD + * for the kernel build + * =========================================================================== + * + * Author Kai Germaschewski + * Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de> + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + * + * + * Introduction: + * + * gcc produces a very nice and correct list of dependencies which + * tells make when to remake a file. + * + * To use this list as-is however has the drawback that virtually + * every file in the kernel includes autoconf.h. + * + * If the user re-runs make *config, autoconf.h will be + * regenerated. make notices that and will rebuild every file which + * includes autoconf.h, i.e. basically all files. This is extremely + * annoying if the user just changed CONFIG_HIS_DRIVER from n to m. + * + * So we play the same trick that "mkdep" played before. We replace + * the dependency on autoconf.h by a dependency on every config + * option which is mentioned in any of the listed prequisites. + * + * kconfig populates a tree in include/config/ with an empty file + * for each config symbol and when the configuration is updated + * the files representing changed config options are touched + * which then let make pick up the changes and the files that use + * the config symbols are rebuilt. + * + * So if the user changes his CONFIG_HIS_DRIVER option, only the objects + * which depend on "include/linux/config/his/driver.h" will be rebuilt, + * so most likely only his driver ;-) + * + * The idea above dates, by the way, back to Michael E Chastain, AFAIK. + * + * So to get dependencies right, there are two issues: + * o if any of the files the compiler read changed, we need to rebuild + * o if the command line given to the compile the file changed, we + * better rebuild as well. + * + * The former is handled by using the -MD output, the later by saving + * the command line used to compile the old object and comparing it + * to the one we would now use. + * + * Again, also this idea is pretty old and has been discussed on + * kbuild-devel a long time ago. I don't have a sensibly working + * internet connection right now, so I rather don't mention names + * without double checking. + * + * This code here has been based partially based on mkdep.c, which + * says the following about its history: + * + * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>. + * This is a C version of syncdep.pl by Werner Almesberger. + * + * + * It is invoked as + * + * fixdep <depfile> <target> <cmdline> + * + * and will read the dependency file <depfile> + * + * The transformed dependency snipped is written to stdout. + * + * It first generates a line + * + * cmd_<target> = <cmdline> + * + * and then basically copies the .<target>.d file to stdout, in the + * process filtering out the dependency on autoconf.h and adding + * dependencies on include/config/my/option.h for every + * CONFIG_MY_OPTION encountered in any of the prequisites. + * + * It will also filter out all the dependencies on *.ver. We need + * to make sure that the generated version checksum are globally up + * to date before even starting the recursive build, so it's too late + * at this point anyway. + * + * The algorithm to grep for "CONFIG_..." is bit unusual, but should + * be fast ;-) We don't even try to really parse the header files, but + * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will + * be picked up as well. It's not a problem with respect to + * correctness, since that can only give too many dependencies, thus + * we cannot miss a rebuild. Since people tend to not mention totally + * unrelated CONFIG_ options all over the place, it's not an + * efficiency problem either. + * + * (Note: it'd be easy to port over the complete mkdep state machine, + * but I don't think the added complexity is worth it) + */ +/* + * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto + * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not + * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as + * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h, + * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that + * those files will have correct dependencies. + */ + +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mman.h> +#include <unistd.h> +#include <fcntl.h> +#include <string.h> +#include <stdlib.h> +#include <stdio.h> +#include <limits.h> +#include <ctype.h> +#include <arpa/inet.h> + +#define INT_CONF ntohl(0x434f4e46) +#define INT_ONFI ntohl(0x4f4e4649) +#define INT_NFIG ntohl(0x4e464947) +#define INT_FIG_ ntohl(0x4649475f) + +char *target; +char *depfile; +char *cmdline; + +static void usage(void) +{ + fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n"); + exit(1); +} + +/* + * Print out the commandline prefixed with cmd_<target filename> := + */ +static void print_cmdline(void) +{ + printf("cmd_%s := %s\n\n", target, cmdline); +} + +struct item { + struct item *next; + unsigned int len; + unsigned int hash; + char name[0]; +}; + +#define HASHSZ 256 +static struct item *hashtab[HASHSZ]; + +static unsigned int strhash(const char *str, unsigned int sz) +{ + /* fnv32 hash */ + unsigned int i, hash = 2166136261U; + + for (i = 0; i < sz; i++) + hash = (hash ^ str[i]) * 0x01000193; + return hash; +} + +/* + * Lookup a value in the configuration string. + */ +static int is_defined_config(const char *name, int len, unsigned int hash) +{ + struct item *aux; + + for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) { + if (aux->hash == hash && aux->len == len && + memcmp(aux->name, name, len) == 0) + return 1; + } + return 0; +} + +/* + * Add a new value to the configuration string. + */ +static void define_config(const char *name, int len, unsigned int hash) +{ + struct item *aux = malloc(sizeof(*aux) + len); + + if (!aux) { + perror("fixdep:malloc"); + exit(1); + } + memcpy(aux->name, name, len); + aux->len = len; + aux->hash = hash; + aux->next = hashtab[hash % HASHSZ]; + hashtab[hash % HASHSZ] = aux; +} + +/* + * Clear the set of configuration strings. + */ +static void clear_config(void) +{ + struct item *aux, *next; + unsigned int i; + + for (i = 0; i < HASHSZ; i++) { + for (aux = hashtab[i]; aux; aux = next) { + next = aux->next; + free(aux); + } + hashtab[i] = NULL; + } +} + +/* + * Record the use of a CONFIG_* word. + */ +static void use_config(const char *m, int slen) +{ + unsigned int hash = strhash(m, slen); + int c, i; + + if (is_defined_config(m, slen, hash)) + return; + + define_config(m, slen, hash); + + printf(" $(wildcard include/config/"); + for (i = 0; i < slen; i++) { + c = m[i]; + if (c == '_') + c = '/'; + else + c = tolower(c); + putchar(c); + } + printf(".h) \\\n"); +} + +static void parse_config_file(const char *map, size_t len) +{ + const int *end = (const int *) (map + len); + /* start at +1, so that p can never be < map */ + const int *m = (const int *) map + 1; + const char *p, *q; + + for (; m < end; m++) { + if (*m == INT_CONF) { p = (char *) m ; goto conf; } + if (*m == INT_ONFI) { p = (char *) m-1; goto conf; } + if (*m == INT_NFIG) { p = (char *) m-2; goto conf; } + if (*m == INT_FIG_) { p = (char *) m-3; goto conf; } + continue; + conf: + if (p > map + len - 7) + continue; + if (memcmp(p, "CONFIG_", 7)) + continue; + for (q = p + 7; q < map + len; q++) { + if (!(isalnum(*q) || *q == '_')) + goto found; + } + continue; + + found: + if (!memcmp(q - 7, "_MODULE", 7)) + q -= 7; + if( (q-p-7) < 0 ) + continue; + use_config(p+7, q-p-7); + } +} + +/* test is s ends in sub */ +static int strrcmp(char *s, char *sub) +{ + int slen = strlen(s); + int sublen = strlen(sub); + + if (sublen > slen) + return 1; + + return memcmp(s + slen - sublen, sub, sublen); +} + +static void do_config_file(const char *filename) +{ + struct stat st; + int fd; + void *map; + + fd = open(filename, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "fixdep: error opening config file: "); + perror(filename); + exit(2); + } + fstat(fd, &st); + if (st.st_size == 0) { + close(fd); + return; + } + map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + if ((long) map == -1) { + perror("fixdep: mmap"); + close(fd); + return; + } + + parse_config_file(map, st.st_size); + + munmap(map, st.st_size); + + close(fd); +} + +/* + * Important: The below generated source_foo.o and deps_foo.o variable + * assignments are parsed not only by make, but also by the rather simple + * parser in scripts/mod/sumversion.c. + */ +static void parse_dep_file(void *map, size_t len) +{ + char *m = map; + char *end = m + len; + char *p; + char s[PATH_MAX]; + int is_target; + int saw_any_target = 0; + int is_first_dep = 0; + + clear_config(); + + while (m < end) { + /* Skip any "white space" */ + while (m < end && (*m == ' ' || *m == '\\' || *m == '\n')) + m++; + /* Find next "white space" */ + p = m; + while (p < end && *p != ' ' && *p != '\\' && *p != '\n') + p++; + /* Is the token we found a target name? */ + is_target = (*(p-1) == ':'); + /* Don't write any target names into the dependency file */ + if (is_target) { + /* The /next/ file is the first dependency */ + is_first_dep = 1; + } else { + /* Save this token/filename */ + memcpy(s, m, p-m); + s[p - m] = 0; + + /* Ignore certain dependencies */ + if (strrcmp(s, "include/generated/autoconf.h") && + strrcmp(s, "arch/um/include/uml-config.h") && + strrcmp(s, "include/linux/kconfig.h") && + strrcmp(s, ".ver")) { + /* + * Do not list the source file as dependency, + * so that kbuild is not confused if a .c file + * is rewritten into .S or vice versa. Storing + * it in source_* is needed for modpost to + * compute srcversions. + */ + if (is_first_dep) { + /* + * If processing the concatenation of + * multiple dependency files, only + * process the first target name, which + * will be the original source name, + * and ignore any other target names, + * which will be intermediate temporary + * files. + */ + if (!saw_any_target) { + saw_any_target = 1; + printf("source_%s := %s\n\n", + target, s); + printf("deps_%s := \\\n", + target); + } + is_first_dep = 0; + } else + printf(" %s \\\n", s); + do_config_file(s); + } + } + /* + * Start searching for next token immediately after the first + * "whitespace" character that follows this token. + */ + m = p + 1; + } + + if (!saw_any_target) { + fprintf(stderr, "fixdep: parse error; no targets found\n"); + exit(1); + } + + printf("\n%s: $(deps_%s)\n\n", target, target); + printf("$(deps_%s):\n", target); +} + +static void print_deps(void) +{ + struct stat st; + int fd; + void *map; + + fd = open(depfile, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "fixdep: error opening depfile: "); + perror(depfile); + exit(2); + } + if (fstat(fd, &st) < 0) { + fprintf(stderr, "fixdep: error fstat'ing depfile: "); + perror(depfile); + exit(2); + } + if (st.st_size == 0) { + fprintf(stderr,"fixdep: %s is empty\n",depfile); + close(fd); + return; + } + map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + if ((long) map == -1) { + perror("fixdep: mmap"); + close(fd); + return; + } + + parse_dep_file(map, st.st_size); + + munmap(map, st.st_size); + + close(fd); +} + +static void traps(void) +{ + static char test[] __attribute__((aligned(sizeof(int)))) = "CONF"; + int *p = (int *)test; + + if (*p != INT_CONF) { + fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianness? %#x\n", + *p); + exit(2); + } +} + +int main(int argc, char *argv[]) +{ + traps(); + + if (argc != 4) + usage(); + + depfile = argv[1]; + target = argv[2]; + cmdline = argv[3]; + + print_cmdline(); + print_deps(); + + return 0; +} |