/* * "Optimize" a list of dependencies as spit out by gcc -MD * for the kernel build * =========================================================================== * * Author Kai Germaschewski * Copyright 2002 by Kai Germaschewski * * 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 prerequisites. * * 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/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, . * This is a C version of syncdep.pl by Werner Almesberger. * * * It is invoked as * * fixdep * * and will read the dependency file * * The transformed dependency snipped is written to stdout. * * It first generates a line * * cmd_ = * * and then basically copies the ..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 prerequisites. * * 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. * * 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) */ #include #include #include #include #include #include #include #include #include static void usage(void) { fprintf(stderr, "Usage: fixdep \n"); exit(1); } /* * In the intended usage of this program, the stdout is redirected to .*.cmd * files. The return value of printf() and putchar() must be checked to catch * any error, e.g. "No space left on device". */ static void xprintf(const char *format, ...) { va_list ap; int ret; va_start(ap, format); ret = vprintf(format, ap); if (ret < 0) { perror("fixdep"); exit(1); } va_end(ap); } static void xputchar(int c) { int ret; ret = putchar(c); if (ret == EOF) { perror("fixdep"); exit(1); } } /* * Print out a dependency path from a symbol name */ static void print_dep(const char *m, int slen, const char *dir) { int c, prev_c = '/', i; xprintf(" $(wildcard %s/", dir); for (i = 0; i < slen; i++) { c = m[i]; if (c == '_') c = '/'; else c = tolower(c); if (c != '/' || prev_c != '/') xputchar(c); prev_c = c; } xprintf(".h) \\\n"); } 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; } /* * Record the use of a CONFIG_* word. */ static void use_config(const char *m, int slen) { unsigned int hash = strhash(m, slen); if (is_defined_config(m, slen, hash)) return; define_config(m, slen, hash); print_dep(m, slen, "include/config"); } /* test if s ends in sub */ static int str_ends_with(const char *s, int slen, const char *sub) { int sublen = strlen(sub); if (sublen > slen) return 0; return !memcmp(s + slen - sublen, sub, sublen); } static void parse_config_file(const char *p) { const char *q, *r; const char *start = p; while ((p = strstr(p, "CONFIG_"))) { if (p > start && (isalnum(p[-1]) || p[-1] == '_')) { p += 7; continue; } p += 7; q = p; while (*q && (isalnum(*q) || *q == '_')) q++; if (str_ends_with(p, q - p, "_MODULE")) r = q - 7; else r = q; if (r > p) use_config(p, r - p); p = q; } } static void *read_file(const char *filename) { struct stat st; int fd; char *buf; fd = open(filename, O_RDONLY); if (fd < 0) { fprintf(stderr, "fixdep: error opening file: "); perror(filename); exit(2); } if (fstat(fd, &st) < 0) { fprintf(stderr, "fixdep: error fstat'ing file: "); perror(filename); exit(2); } buf = malloc(st.st_size + 1); if (!buf) { perror("fixdep: malloc"); exit(2); } if (read(fd, buf, st.st_size) != st.st_size) { perror("fixdep: read"); exit(2); } buf[st.st_size] = '\0'; close(fd); return buf; } /* Ignore certain dependencies */ static int is_ignored_file(const char *s, int len) { return str_ends_with(s, len, "include/generated/autoconf.h") || str_ends_with(s, len, "include/generated/autoksyms.h") || str_ends_with(s, len, ".ver"); } /* * 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(char *m, const char *target) { char *p; int is_last, is_target; int saw_any_target = 0; int is_first_dep = 0; void *buf; while (1) { /* Skip any "white space" */ while (*m == ' ' || *m == '\\' || *m == '\n') m++; if (!*m) break; /* Find next "white space" */ p = m; while (*p && *p != ' ' && *p != '\\' && *p != '\n') p++; is_last = (*p == '\0'); /* 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 if (!is_ignored_file(m, p - m)) { *p = '\0'; /* * 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; xprintf("source_%s := %s\n\n", target, m); xprintf("deps_%s := \\\n", target); } is_first_dep = 0; } else { xprintf(" %s \\\n", m); } buf = read_file(m); parse_config_file(buf); free(buf); } if (is_last) break; /* * 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); } xprintf("\n%s: $(deps_%s)\n\n", target, target); xprintf("$(deps_%s):\n", target); } int main(int argc, char *argv[]) { const char *depfile, *target, *cmdline; void *buf; if (argc != 4) usage(); depfile = argv[1]; target = argv[2]; cmdline = argv[3]; xprintf("cmd_%s := %s\n\n", target, cmdline); buf = read_file(depfile); parse_dep_file(buf, target); free(buf); return 0; } /> -rw-r--r--drivers/net/wireless/airo.c8264