| /* |
| * "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 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" 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 for every |
| * CONFIG_MY_OPTION encountered in any of the prerequisites. |
| * |
| * 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 <sys/types.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| #include <fcntl.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <ctype.h> |
| |
| static void usage(void) |
| { |
| fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n"); |
| exit(1); |
| } |
| |
| struct item { |
| struct item *next; |
| unsigned int len; |
| unsigned int hash; |
| char name[]; |
| }; |
| |
| #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 out a dependency path from a symbol name. */ |
| printf(" $(wildcard include/config/%.*s) \\\n", slen, m); |
| } |
| |
| /* 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 (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"); |
| } |
| |
| /* |
| * 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; |
| printf("source_%s := %s\n\n", |
| target, m); |
| printf("deps_%s := \\\n", target); |
| } |
| is_first_dep = 0; |
| } else { |
| printf(" %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); |
| } |
| |
| printf("\n%s: $(deps_%s)\n\n", target, target); |
| printf("$(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]; |
| |
| printf("cmd_%s := %s\n\n", target, cmdline); |
| |
| buf = read_file(depfile); |
| parse_dep_file(buf, target); |
| free(buf); |
| |
| fflush(stdout); |
| |
| /* |
| * In the intended usage, the stdout is redirected to .*.cmd files. |
| * Call ferror() to catch errors such as "No space left on device". |
| */ |
| if (ferror(stdout)) { |
| fprintf(stderr, "fixdep: not all data was written to the output\n"); |
| exit(1); |
| } |
| |
| return 0; |
| } |