Do you think kernel build is 100% dominated by gcc? You are wrong!
One small utility called "fixdep" consistently manages to sneak into
profile's first page (unless you have small monitor of course).
The choke point is this clever code:
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; }
4 branches per 4 characters is not fast.
Use strstr(3), so that SSE2 etc can be used.
With this patch, fixdep is so deep at the bottom, it is hard to find it.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Like with kconfig options, we now have the ability to compile in and
out individual EXPORT_SYMBOL() declarations based on the content of
include/generated/autoksyms.h. However we don't want the entire
world to be rebuilt whenever that file is touched.
Let's apply the same build dependency trick used for CONFIG_* symbols
where the time stamp of empty files whose paths matching those symbols
is used to trigger fine grained rebuilds. In our case the key is the
symbol name passed to EXPORT_SYMBOL().
However, unlike config options, we cannot just use fixdep to parse
the source code for EXPORT_SYMBOL(ksym) because several variants exist
and parsing them all in a separate tool, and keeping it in synch, is
not trivially maintainable. Furthermore, there are variants such as
EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
that are instanciated via a macro for which we can't easily determine
the actual exported symbol name(s) short of actually running the
preprocessor on them.
Storing the symbol name string in a special ELF section doesn't work
for targets that output assembly or preprocessed source.
So the best way is really to leverage the preprocessor by having it
output actual symbol names anchored by a special sequence that can be
easily filtered out. Then the list of symbols is simply fed to fixdep
to be merged with the other dependencies.
That implies the preprocessor is executed twice for each source file.
A previous attempt relied on a warning pragma for each EXPORT_SYMBOL()
instance that was filtered apart from stderr by the build system with
a sed script during the actual compilation pass. Unfortunately the
preprocessor/compiler diagnostic output isn't stable between versions
and this solution, although more efficient, was deemed too fragile.
Because of the lowercasing performed by fixdep, there might be name
collisions triggering spurious rebuilds for similar symbols. But this
shouldn't be a big issue in practice. (This is the case for CONFIG_*
symbols and I didn't want to be different here, whatever the original
reason for doing so.)
To avoid needless build overhead, the exported symbol name gathering is
performed only when CONFIG_TRIM_UNUSED_KSYMS is selected.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Coverity has recently added a check that will find when we don't check
the return code from fstat(2). Copy/paste the checking logic that
print_deps() has with an appropriate re-wording of the perror() message.
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
strrcmp only performs read access to the memory addressed by its
arguments so make them const pointers.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
The clear_config() is called just once at the beginning of this
program, but the global variable hashtab[] is already zero-filled
at the start-up.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
If the target string matches "CONFIG_", move the pointer p
forward. This saves several 7-chars adjustments.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
The current use-case for fixdep is: a source file is run through a single
processing step, which creates a single dependency file as a side-effect,
which fixdep transforms into the file used by the kernel build process.
In order to transparently run the C pre-processor on device-tree files,
we wish to run both gcc -E and dtc on a source file in a single rule.
This generates two dependency files, which must be transformed together
into the file used by the kernel build process. This change modifies
fixdep so it can process the concatenation of multiple separate input
dependency files, and produce a correct unified output.
The code changes have the slight benefit of transforming the loop in
parse_dep_file() into more of a lexer/tokenizer, with the loop body being
more of a parser. Previously, some of this logic was mixed together
before the loop. I also added some comments, which I hope are useful.
Benchmarking shows that on a cross-compiled ARM tegra_defconfig build,
there is less than 0.5 seconds speed decrease with this change, on top
of a build time of ~2m24s. This is probably within the noise.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
The introduction of include/linux/kconfig.h created 3 extraneous
dependencies:
include/config/.h
include/config/h.h
include/config/foo.h
Fix this by excluding kconfig.h from fixdep calculations.
Signed-off-by: Peter Foley <pefoley2@verizon.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Recent change to fixdep:
commit b7bd182176
Author: Michal Marek <mmarek@suse.cz>
Date: Thu Feb 17 15:13:54 2011 +0100
fixdep: Do not record dependency on the source file itself
changed the format of the *.cmd files without realizing that it is also
used by modpost. Put the path to the source file to the file back, in a
special variable, so that modpost sees all source files when calculating
srcversion for modules.
Reported-and-tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The dependency is already expressed by the Makefiles, storing it in the
.cmd file breaks build if a .c file is replaced by .S or vice versa,
because the .cmd file contains
foo/bar.o: foo/bar.c ...
foo/bar.c ... :
so the foo/bar.c -> foo/bar.o rule triggers even if there is no
foo/bar.c anymore.
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michal Marek <mmarek@suse.cz>
I noticed fixdep uses ~2% of cpu time in kernel build, in function
use_config()
fixdep spends a lot of cpu cycles in linear searches in its internal
string array. With about 400 stored strings per dep file, this begins to
be noticeable.
Convert fixdep to use a hash table.
kbuild results on my x86_64 allmodconfig
Before patch :
real 10m30.414s
user 61m51.456s
sys 8m28.200s
real 10m12.334s
user 61m50.236s
sys 8m30.448s
real 10m42.947s
user 61m50.028s
sys 8m32.380s
After:
real 10m8.180s
user 61m22.506s
sys 8m32.384s
real 10m35.039s
user 61m21.654s
sys 8m32.212s
real 10m14.487s
user 61m23.498s
sys 8m32.312s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next: (30 commits)
Use macros for .data.page_aligned section.
Use macros for .bss.page_aligned section.
Use new __init_task_data macro in arch init_task.c files.
kbuild: Don't define ALIGN and ENTRY when preprocessing linker scripts.
arm, cris, mips, sparc, powerpc, um, xtensa: fix build with bash 4.0
kbuild: add static to prototypes
kbuild: fail build if recordmcount.pl fails
kbuild: set -fconserve-stack option for gcc 4.5
kbuild: echo the record_mcount command
gconfig: disable "typeahead find" search in treeviews
kbuild: fix cc1 options check to ensure we do not use -fPIC when compiling
checkincludes.pl: add option to remove duplicates in place
markup_oops: use modinfo to avoid confusion with underscored module names
checkincludes.pl: provide usage helper
checkincludes.pl: close file as soon as we're done with it
ctags: usability fix
kernel hacking: move STRIP_ASM_SYMS from General
gitignore usr/initramfs_data.cpio.bz2 and usr/initramfs_data.cpio.lzma
kbuild: Check if linker supports the -X option
kbuild: introduce ld-option
...
Fix trivial conflict in scripts/basic/fixdep.c
Ignore drivers/staging/ since it is very likely that new drivers
introduce it again.
Signed-off-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Warnings found via gcc -Wmissing-prototypes.
Signed-off-by: Trevor Keith <tsrk@tsrk.net>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
gcc-4.4.1:
HOSTCC scripts/basic/fixdep
scripts/basic/fixdep.c: In function 'traps':
scripts/basic/fixdep.c:377: warning: dereferencing type-punned pointer will break strict-aliasing rules
scripts/basic/fixdep.c:379: warning: dereferencing type-punned pointer will break strict-aliasing rules
(Apparently -fno-strict-aliasing will fix this too)
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
build scripts: fixdep blows segfault on string CONFIG_MODULE seen
The string "CONFIG_MODULE" appearing anywhere in a source file causes
fixdep to segfault. This string appeared in the wild in the current
mISDN sources (I think they meant CONFIG_MODULES). But it shouldn't
segfault (esp as CONFIG_MODULE appeared in a quoted string).
Signed-off-by: Andy Green <andy@warmcat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Commit 2e3646e51b changed the way the
split config tree is built, but failed to also adjust fixdep accordingly
- if changing a config option from or to m, files referencing the
respective CONFIG_..._MODULE (but not the corresponding CONFIG_...)
didn't get rebuilt.
The problem is that trisate symbol are represent with three different
symbols:
SYMBOL=n => no symbol defined
SYMBOL=y => CONFIG_SYMBOL defined to '1'
SYMBOL=m => CONFIG_SYMBOL_MODULE defined to '1'
But conf_split_config do not distingush between the =y and =m case, so
only the =y case is honoured.
This is fixed in fixdep so when a CONFIG symbol with _MODULE is found we
skip that part and only look for the CONFIG_SYMBOL version.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While the recent change to also escape # symbols when storing C-file
compilation command lines was helpful, it should be in effect for all
command lines, as much as the dollar escaping should be in effect for
C-source compilation commands. Additionally, for better readability and
maintenance, consolidating all the escaping (single quotes, dollars,
and now sharps) was also desirable.
Signed-Off-By: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Commandlines are contained in the .<target>.cmd files and in case they
contain a '#' char make see this as start of comment.
Teach fixdep to escape the '#' char so make will assing the full commandline.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
scripts/ is full of mismatches between char* params an signed char* arguments,
and viceversa. gcc4 now complaints loud about this. Patch below deletes all
those 'signed'.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
