Re: [kbuild-devel] Re: State of the new config build system
Hi Keith,
That is exactly what kbuild 2.5 does. The slowdown occurs when
massaging the -MD dependencies from absolute names to relative path
names. To support separate source and object trees, renaming of trees,
different names in local and NFS mode etc., the massage code needs a
list of where all the files are before it can convert the absolute
dependencies produced by gcc. Reading and indexing that file for every
compile is _slow_.
I didn't follow the thread from the very beginning nor did I study
your makefiles carefully, because I don't have much time for kernel
hacking these days, but maybe I won't miss the pond :)
Is there any reason for processing all the files for each compile
instead of merging them to a single file once at the start of the make?
I use it in one of my projects, there is the relevant part of the
Makefile:
# Black magic with dependencies. It would be more correct to make depend.new
# a prerequisite for depend, but depend.new often has the same timestamp
# as depend which would confuse make a lot and either force remaking anyway
# or (as in current versions of GNU make) erroneously skipping the remaking.
-include depend
depend: force
if [ -s depend.new ] ; then build/mergedeps depend depend.new ; depend.new ;
fi
force:
# Implicit rules
obj/%.o: %.c
DEPENDENCIES_OUTPUT=depend.new $@ $(CC) $(CFLAGS) -c -o $@ $
The DEPENDENCIES_OUTPUT mode is much more convenient than gcc -Mx as it
avoids scattering the relevant information over many files. The mergedeps
script is a simple Perl script which takes care of merging the dependencies
gathered during the previous run of make to the depend file for the next
run. It can do a lot of fixups and translations, here is a trivial
example:
#!/usr/bin/perl
@ARGV == 2 or die Usage: mergedeps base update;
foreach $a (@ARGV) {
open F, $a or next;
$t = ;
while (F) {
$t .= $_;
if (! /\\$/) {
($t =~ /^(.*):/) || die Parse error at $t;
$rules{$1} = $t;
$t = ;
}
}
close F;
}
open(F, . $ARGV[0]) || die Unable to write output file;
foreach $a (sort keys %rules) {
print F $rules{$a};
}
close F;
Have a nice fortnight
--
Martin `MJ' Mares [EMAIL PROTECTED] http://atrey.karlin.mff.cuni.cz/~mj/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
Light-year? One-third less calories than a regular year.
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Re: [kbuild-devel] Re: State of the new config build system
On Sun, 6 Jan 2002 09:55:49 +0100, Martin Mares [EMAIL PROTECTED] wrote: Is there any reason for processing all the files for each compile instead of merging them to a single file once at the start of the make? The main reason is to convert absolute dependency names to $(xxx) followed by a relative name, where xxx is one of the KBUILD_OBJTREE or KBUILD_SRCTREE_nnn variables. This conversion allows users to rename their source and object trees and to compile on one machine and install on another over NFS without being bitten by absolute dependencies. I really need to do that conversion using the current values of the kbuild variables, the variables might have changed on the next make. My new design for module symbol versions requires that the version data be stored immediately after the compile. That also requires processing after each compile using the current environment. ___ kbuild-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/kbuild-devel
[kbuild-devel] CML@-2.0.3
Release 2.0.3: Sun Jan 6 19:04:28 EST 2002 * Massive autoprobe rules update by Giacomo. * Vital symbols (those that are critical, like disk drivers for potential root devices) are now forced to Y when the autoconfigurator finds their hardware. The autoconfigurator is much snmarter now, but running a manual configure afterwards is recommended. This release also fixes a bug in field entry of hexadecimal symbol values. -- a href=http://www.tuxedo.org/~esr/;Eric S. Raymond/a Since there is no such entity as 'the public,' since the public is merely a number of individuals, the idea that 'the public interest' supersedes private interests and rights can have but one meaning: that the interests and rights of some individuals take precedence over the interests and rights of others. -- Ayn Rand ___ kbuild-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/kbuild-devel
[kbuild-devel] possible bug in arch/sparc/mm/Makefile.in
Hello, I am not sure but here is a possible bug. Please check it carefully. arch/sparc/mm/Makefile.in: select(CONFIG_SUN4 osrmmu.o) should be select(CONFIG_SUN4 nosrmmu.o) JL ___ kbuild-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/kbuild-devel
