403 lines
9.9 KiB
C
403 lines
9.9 KiB
C
/*
|
|
* "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.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 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 <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 [-e] <depfile> <target> <cmdline>\n");
|
|
fprintf(stderr, " -e insert extra dependencies given on stdin\n");
|
|
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;
|
|
|
|
printf(" $(wildcard %s/", dir);
|
|
for (i = 0; i < slen; i++) {
|
|
c = m[i];
|
|
if (c == '_')
|
|
c = '/';
|
|
else
|
|
c = tolower(c);
|
|
if (c != '/' || prev_c != '/')
|
|
putchar(c);
|
|
prev_c = c;
|
|
}
|
|
printf(".h) \\\n");
|
|
}
|
|
|
|
static void do_extra_deps(void)
|
|
{
|
|
char buf[80];
|
|
|
|
while (fgets(buf, sizeof(buf), stdin)) {
|
|
int len = strlen(buf);
|
|
|
|
if (len < 2 || buf[len - 1] != '\n') {
|
|
fprintf(stderr, "fixdep: bad data on stdin\n");
|
|
exit(1);
|
|
}
|
|
print_dep(buf, len - 1, "include/ksym");
|
|
}
|
|
}
|
|
|
|
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, int insert_extra_deps)
|
|
{
|
|
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);
|
|
}
|
|
|
|
if (insert_extra_deps)
|
|
do_extra_deps();
|
|
|
|
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;
|
|
int insert_extra_deps = 0;
|
|
void *buf;
|
|
|
|
if (argc == 5 && !strcmp(argv[1], "-e")) {
|
|
insert_extra_deps = 1;
|
|
argv++;
|
|
} else 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, insert_extra_deps);
|
|
free(buf);
|
|
|
|
return 0;
|
|
}
|