1 File.........: overview.txt
2 Content......: Overview of how crosstool-NG works.
3 Copyrigth....: (C) 2007 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>
4 License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5
14 Referring to crosstool-NG
15 Installing crosstool-NG
18 Preparing for packaging
21 Configuring crosstool-NG
22 Interesting config options
23 Re-building an existing toolchain
24 Using as a backend for a build-system
26 Stopping and restarting a build
27 Testing all toolchains at once
28 Overriding the number of // jobs
34 Seemingly-native toolchains
42 Adding a new version of a component
51 crosstool-NG aims at building toolchains. Toolchains are an essential component
52 in a software development project. It will compile, assemble and link the code
53 that is being developed. Some pieces of the toolchain will eventually end up
54 in the resulting binary/ies: static libraries are but an example.
56 So, a toolchain is a very sensitive piece of software, as any bug in one of the
57 components, or a poorly configured component, can lead to execution problems,
58 ranging from poor performance, to applications ending unexpectedly, to
59 mis-behaving software (which more than often is hard to detect), to hardware
60 damage, or even to human risks (which is more than regrettable).
62 Toolchains are made of different piece of software, each being quite complex
63 and requiring specially crafted options to build and work seamlessly. This
64 is usually not that easy, even in the not-so-trivial case of native toolchains.
65 The work reaches a higher degree of complexity when it comes to cross-
66 compilation, where it can become quite a nightmare...
68 Some cross-toolchains exist on the internet, and can be used for general
69 development, but they have a number of limitations:
70 - they can be general purpose, in that they are configured for the majority:
71 no optimisation for your specific target,
72 - they can be prepared for a specific target and thus are not easy to use,
73 nor optimised for, or even supporting your target,
74 - they often are using aging components (compiler, C library, etc...) not
75 supporting special features of your shiny new processor;
76 On the other side, these toolchain offer some advantages:
77 - they are ready to use and quite easy to install and setup,
78 - they are proven if used by a wide community.
80 But once you want to get all the juice out of your specific hardware, you will
81 want to build your own toolchain. This is where crosstool-NG comes into play.
83 There are also a number of tools that build toolchains for specific needs,
84 which are not really scalable. Examples are:
85 - buildroot (buildroot.uclibc.org) whose main purpose is to build root file
86 systems, hence the name. But once you have your toolchain with buildroot,
87 part of it is installed in the root-to-be, so if you want to build a whole
88 new root, you either have to save the existing one as a template and
89 restore it later, or restart again from scratch. This is not convenient,
90 - ptxdist (www.pengutronix.de/software/ptxdist), whose purpose is very
92 - other projects (openembedded.org for example), which are again used to
93 build root file systems.
95 crosstool-NG is really targeted at building toolchains, and only toolchains.
96 It is then up to you to use it the way you want.
104 crosstool was first 'conceived' by Dan Kegel, who offered it to the community
105 as a set of scripts, a repository of patches, and some pre-configured, general
106 purpose setup files to be used to configure crosstool. This is available at
107 http://www.kegel.com/crosstool, and the subversion repository is hosted on
108 google at http://code.google.com/p/crosstool/.
110 I once managed to add support for uClibc-based toolchains, but it did not make
111 into mainline, mostly because I didn't have time to port the patch forward to
112 the new versions, due in part to the big effort it was taking.
114 So I decided to clean up crosstool in the state it was, re-order the things
115 in place, add appropriate support for what I needed, that is uClibc support
116 and a menu-driven configuration, named the new implementation crosstool-NG,
117 (standing for crosstool Next Generation, as many other comunity projects do,
118 and as a wink at the TV series "Star Trek: The Next Generation" ;-) ) and
119 made it available to the community, in case it was of interest to any one.
122 _____________________________
124 Referring to crosstool-NG /
125 __________________________/
128 The long name of the project is crosstool-NG:
129 * no leading uppercase (except as first word in a sentence)
130 * crosstool and NG separated with a hyphen (dash)
133 Crosstool-NG can also be referred to by its short name CT-NG:
135 * CT and NG separated with a hyphen (dash)
137 The long name is preferred over the short name, except in mail subjects, where
138 the short name is a better fit.
140 When referring to a specific version of crosstool-NG, append the version number
143 - the long name, a space, and the version string
145 - the long name in lowercase, a hyphen (dash), and the version string
146 - this is used to name the release tarballs
147 * crosstool-ng-X.Y.Z+hg_id
148 - the long name in lowercase, a hyphen, the version string, and the Hg id
149 (as returned by: ct-ng version)
150 - this is used to differentiate between releases and snapshots
152 The frontend to crosstool-NG is the command ct-ng:
154 * ct and ng separated by a hyphen (dash)
157 ___________________________
159 Installing crosstool-NG /
160 ________________________/
162 There are two ways you can use crosstool-NG:
163 - build and install it, then get rid of the sources like you'd do for most
165 - or only build it and run from the source directory.
167 The former should be used if you got crosstool-NG from a packaged tarball, see
168 "Install method", below, while the latter is most useful for developpers that
169 use a clone of the repository, and want to submit patches, see "The Hacker's
175 If you go for the install, then you just follow the classical, but yet easy
177 ./configure --prefix=/some/place
180 export PATH="${PATH}:/some/place/bin"
182 You can then get rid of crosstool-NG source. Next create a directory to serve
183 as a working place, cd in there and run:
186 See below for complete usage.
191 If you go the hacker's way, then the usage is a bit different, although very
196 Now, *do not* remove crosstool-NG sources. They are needed to run crosstool-NG!
197 Stay in the directory holding the sources, and run:
200 See below for complete usage.
202 Now, provided you used a clone of the repository, you can send me your changes.
203 See the section titled CONTRIBUTING, below, for how to submit changees.
205 Preparing for packaging |
206 ------------------------+
208 If you plan on packaging crosstool-NG, you surely don't want to install it
209 in your root file system. The install procedure of crosstool-NG honors the
212 ./configure --prefix=/usr
214 make DESTDIR=/packaging/place install
219 crosstool-NG comes with a shell script fragment that defines bash-compatible
220 completion. That shell fragment is currently not installed automatically, but
223 To install the shell script fragment, you have two options:
224 - install system-wide, most probably by copying ct-ng.comp into
225 /etc/bash_completion.d/
226 - install for a single user, by copying ct-ng.comp into ${HOME}/ and
227 sourcing this file from your ${HOME}/.bashrc
232 Some people contibuted code that couldn't get merged for various reasons. This
233 code is available as lzma-compressed patches, in the contrib/ sub-directory.
234 These patches are to be applied to the source of crosstool-NG, prior to
235 installing, using something like the following:
236 lzcat contrib/foobar.patch.lzma |patch -p1
238 There is no guarantee that a particuliar contribution applies to the current
239 version of crosstool-ng, or that it will work at all. Use contributions at
243 ____________________________
245 Configuring crosstool-NG /
246 _________________________/
248 crosstool-NG is configured with a configurator presenting a menu-stuctured set
249 of options. These options let you specify the way you want your toolchain
250 built, where you want it installed, what architecture and specific processor it
251 will support, the version of the components you want to use, etc... The
252 value for those options are then stored in a configuration file.
254 The configurator works the same way you configure your Linux kernel. It is
255 assumed you now how to handle this.
257 To enter the menu, type:
260 Almost every config item has a help entry. Read them carefully.
262 String and number options can refer to environment variables. In such a case,
263 you must use the shell syntax: ${VAR}. You shall neither single- nor double-
264 quote the string/number options.
266 There are three environment variables that are computed by crosstool-NG, and
270 It represents the target tuple you are building for. You can use it for
271 example in the installation/prefix directory, such as:
272 /opt/x-tools/${CT_TARGET}
275 The top directory where crosstool-NG is running. You shouldn't need it in
276 most cases. There is one case where you may need it: if you have local
277 patches and you store them in your running directory, you can refer to them
278 by using CT_TOP_DIR, such as:
279 ${CT_TOP_DIR}/patches.myproject
282 The version of crosstool-NG you are using. Not much use for you, but it's
283 there if you need it.
285 Interesting config options |
286 ---------------------------+
288 CT_LOCAL_TARBALLS_DIR:
289 If you already have some tarballs in a direcotry, enter it here. That will
290 speed up the retrieving phase, where crosstool-NG would otherwise download
294 This is where the toolchain will be installed in (and for now, where it
295 will run from). Common use is to add the target tuple in the directory
296 path, such as (see above):
297 /opt/x-tools/${CT_TARGET}
300 An identifier for your toolchain, will take place in the vendor part of the
301 target tuple. It shall *not* contain spaces or dashes. Usually, keep it
302 to a one-word string, or use underscores to separate words if you need.
303 Avoid dots, commas, and special characters.
306 An alias for the toolchian. It will be used as a prefix to the toolchain
307 tools. For example, you will have ${CT_TARGET_ALIAS}-gcc
309 Also, if you think you don't see enough versions, you can try to enable one of
313 Show obsolete versions or tools. Most of the time, you don't want to base
314 your toolchain on too old a version (of gcc, for example). But at times, it
315 can come handy to use such an old version for regression tests. Those old
316 versions are hidden behind CT_OBSOLETE. Those versions (or features) are so
317 marked because maintaining support for those in crosstool-NG would be too
318 costly, time-wise, and time is dear.
321 Show experimental versions or tools. Again, you might not want to base your
322 toolchain on too recent tools (eg. gcc) for production. But if you need a
323 feature present only in a recent version, or a new tool, you can find them
324 hidden behind CT_EXPERIMENTAL. Those versions (or features) did not (yet)
325 receive thorough testing in crosstool-NG, and/or are not mature enough to
328 Re-building an existing toolchain |
329 ----------------------------------+
331 If you have an existing toolchain, you can re-use the options used to build it
332 to create a new toolchain. That needs a very little bit of effort on your side
333 but is quite easy. The options to build a toolchain are saved with the
334 toolchain, and you can retrieve this configuration by running:
335 ${CT_TARGET}-ct-ng.config
337 An alternate method is to extract the configuration from a build.log file.
338 This will be necessary if your toolchain was build with crosstool-NG prior
339 to 1.4.0, but can be used with build.log files from any version:
340 ct-ng extractconfig <build.log >.config
342 Or, if your build.log file is compressed (most probably!):
343 bzcat build.log.bz2 |ct-ng extractconfig >.config
345 The above commands will dump the configuration to stdout, so to rebuild a
346 toolchain with this configuration, just redirect the output to the
348 ${CT_TARGET}-ct-ng.config >.config
351 Then, you can review and change the configuration by running:
354 Using as a backend for a build-system |
355 --------------------------------------+
357 Crosstool-NG can be used as a backend for an automated build-system. In this
358 case, some components that are expected to run on the target (eg. the native
359 gdb, ltrace, DUMA...) are not available in the menuconfig, and they are not
360 build either, as it is considered the responsibility of the build-system to
361 build its own versions of those tools.
363 If you want to use crosstool-NG as a backend to generate your toolchains for
364 your build-system, you have to set and export this environment variable:
367 (case is not sensitive, you can say Y).
370 ________________________
372 Running crosstool-NG /
373 _____________________/
375 To build the toolchain, simply type:
378 This will use the above configuration to retrieve, extract and patch the
379 components, build, install and eventually test your newly built toolchain.
381 You are then free to add the toolchain /bin directory in your PATH to use
384 In any case, you can get some terse help. Just type:
389 Stopping and restarting a build |
390 --------------------------------+
392 If you want to stop the build after a step you are debugging, you can pass the
393 variable STOP to make:
394 ct-ng build STOP=some_step
396 Conversely, if you want to restart a build at a specific step you are
397 debugging, you can pass the RESTART variable to make:
398 ct-ng build RESTART=some_step
400 Alternatively, you can call make with the name of a step to just do that step:
403 ct-ng build RESTART=libc_headers STOP=libc_headers
405 The shortcuts +step_name and step_name+ allow to respectively stop or restart
407 ct-ng +libc_headers and: ct-ng libc_headers+
409 ct-ng build STOP=libc_headers and: ct-ng build RESTART=libc_headers
411 To obtain the list of acceptable steps, please call:
414 Note that in order to restart a build, you'll have to say 'Y' to the config
415 option CT_DEBUG_CT_SAVE_STEPS, and that the previous build effectively went
418 Building all toolchains at once |
419 --------------------------------+
421 You can build all samples; simply call:
424 Overriding the number of // jobs |
425 ---------------------------------+
427 If you want to override the number of jobs to run in // (the -j option to
428 make), you can either re-enter the menuconfig, or simply add it on the command
432 which tells crosstool-NG to override the number of // jobs to 4.
434 You can see the actions that support overriding the number of // jobs in
435 the help menu. Those are the ones with [.#] after them (eg. build[.#] or
436 build-all[.#], and so on...).
441 The crosstool-NG script 'ct-ng' is a Makefile-script. It does *not* execute
442 in parallel (there is not much to gain). When speaking of // jobs, we are
443 refering to the number of // jobs when making the *components*. That is, we
444 speak of the number of // jobs used to build gcc, glibc, and so on...
449 Starting with gcc-4.3 come two new dependencies: GMP and MPFR. With gcc-4.4,
450 come three new ones: PPL, CLooG/ppl and MPC. With gcc-4.5 again comes a new
451 dependency on libelf. These are libraries that enable advanced features to
452 gcc. Additionally, some of those libraries can be used by binutils and gdb.
453 Unfortunately, not all systems on which crosstool-NG runs have all of those
454 libraries. And for those that do, the versions of those libraries may be
455 older than the version required by gcc (and binutils and gdb). To date,
456 Debian stable (aka Lenny) is lagging behind on some, and is missing the
459 This is why crosstool-NG builds its own set of libraries as part of the
462 The companion libraries can be built either as static libraries, or as shared
463 libraries. The default is to build static libraries, and is the safe way.
464 If you decide to use static companion libraries, then you can stop reading
467 But if you prefer to have shared libraries, then read on...
469 Building shared companion libraries poses no problem at build time, as
470 crosstool-NG correctly points gcc (and binutils and gdb) to the correct
471 place where our own version of the libraries are installed. But it poses
472 a problem when gcc et al. are run: the place where the libraries are is most
473 probably not known to the host dynamic linker. Still worse, if the host system
474 has its own versions, then ld.so would load the wrong libraries!
476 So we have to force the dynamic linker to load the correct version. We do this
477 by using the LD_LIBRARY_PATH variable, that informs the dynamic linker where
478 to look for shared libraries prior to searching its standard places. But we
479 can't impose that burden on all the system (because it'd be a nightmare to
480 configure, and because two toolchains on the same system may use different
481 versions of the libraries); so we have to do it on a per-toolchain basis.
483 So we rename all binaries of the toolchain (by adding a dot '.' as their first
484 character), and add a small program, the so-called "tools wrapper", that
485 correctly sets LD_LIBRARY_PATH prior to running the real tool.
487 First, the wrapper was written as a POSIX-compliant shell script. That shell
488 script is very simple, if not trivial, and works great. The only drawback is
489 that it does not work on host systems that lack a shell, for example the
490 MingW32 environment. To solve the issue, the wrapper has been re-written in C,
491 and compiled at build time. This C wrapper is much more complex than the shell
492 script, and although it sems to be working, it's been only lightly tested.
493 Some of the expected short-comings with this C wrapper are;
494 - multi-byte file names may not be handled correctly
495 - it's really big for what it does
497 So, the default wrapper installed with your toolchain is the shell script.
498 If you know that your system is missing a shell, then you shall use the C
499 wrapper (and report back whether it works, or does not work, for you).
501 A final word on the subject: do not build shared libraries. Build them
502 static, and you'll be safe.
505 _______________________
507 Using the toolchain /
508 ____________________/
510 Using the toolchain is as simple as adding the toolchain's bin directory in
512 export PATH="${PATH}:/your/toolchain/path/bin"
514 and then using the target tuple to tell the build systems to use your
516 ./configure --target=your-target-tuple
518 make CC=your-target-tuple-gcc
520 make CROSS_COMPILE=your-target-tuple-
523 It is strongly advised not to use the toolchain sys-root directory as an
524 install directory for your programs/packages. If you do so, you will not be
525 able to use your toolchain for another project. It is even strongly advised
526 that your toolchain is chmod-ed to read-only once successfully build, so that
527 you don't go polluting your toolchain with your programs/packages' files.
529 Thus, when you build a program/package, install it in a separate directory,
530 eg. /your/root. This directory is the /image/ of what would be in the root file
531 system of your target, and will contain all that your programs/packages have
534 The 'populate' script |
535 ----------------------+
537 When your root directory is ready, it is still missing some important bits: the
538 toolchain's libraries. To populate your root directory with those libs, just
540 your-target-tuple-populate -s /your/root -d /your/root-populated
542 This will copy /your/root into /your/root-populated, and put the needed and only
543 the needed libraries there. Thus you don't polute /your/root with any cruft that
544 would no longer be needed should you have to remove stuff. /your/root always
545 contains only those things you install in it.
547 You can then use /your/root-populated to build up your file system image, a
548 tarball, or to NFS-mount it from your target, or whatever you need.
550 The populate script accepts the following options:
553 Use 'src_dir' as the un-populated root directory.
556 Put the populated root directory in 'dst_dir'.
559 Always add specified libraries.
562 Always add libraries listed in 'file'.
565 Remove 'dst_dir' if it previously existed; continue even if any library
566 specified with -l or -L is missing.
569 Be verbose, and tell what's going on (you can see exactly where libs are
575 See 'your-target-tuple-populate -h' for more information on the options.
577 Here is how populate works:
579 1) performs some sanity checks:
580 - src_dir and dst_dir are specified
582 - unless forced, dst_dir does not exist
585 2) copy src_dir to dst_dir
587 3) add forced libraries to dst_dir
588 - build the list from -l and -L options
589 - get forced libraries from the sysroot (see below for heuristics)
590 - abort on the first missing library, unless -f is specified
592 4) add all missing libraries to dst_dir
593 - scan dst_dir for every ELF files that are 'executable' or
595 - list the "NEEDED Shared library" fields
596 - check if the library is already in dst_dir/lib or dst_dir/usr/lib
597 - if not, get the library from the sysroot
598 - if it's in sysroot/lib, copy it to dst_dir/lib
599 - if it's in sysroot/usr/lib, copy it to dst_dir/usr/lib
600 - in both cases, use the SONAME of the library to create the file
602 - if it was not found in the sysroot, this is an error.
610 There are four kinds of toolchains you could encounter.
612 First off, you must understand the following: when it comes to compilers there
613 are up to four machines involved:
614 1) the machine configuring the toolchain components: the config machine
615 2) the machine building the toolchain components: the build machine
616 3) the machine running the toolchain: the host machine
617 4) the machine the toolchain is generating code for: the target machine
619 We can most of the time assume that the config machine and the build machine
620 are the same. Most of the time, this will be true. The only time it isn't
621 is if you're using distributed compilation (such as distcc). Let's forget
622 this for the sake of simplicity.
624 So we're left with three machines:
629 Any toolchain will involve those three machines. You can be as pretty sure of
630 this as "2 and 2 are 4". Here is how they come into play:
632 1) build == host == target
633 This is a plain native toolchain, targetting the exact same machine as the
634 one it is built on, and running again on this exact same machine. You have
635 to build such a toolchain when you want to use an updated component, such
636 as a newer gcc for example.
637 crosstool-NG calls it "native".
639 2) build == host != target
640 This is a classic cross-toolchain, which is expected to be run on the same
641 machine it is compiled on, and generate code to run on a second machine,
643 crosstool-NG calls it "cross".
645 3) build != host == target
646 Such a toolchain is also a native toolchain, as it targets the same machine
647 as it runs on. But it is build on another machine. You want such a
648 toolchain when porting to a new architecture, or if the build machine is
649 much faster than the host machine.
650 crosstool-NG calls it "cross-native".
652 4) build != host != target
653 This one is called a canadian-toolchain (*), and is tricky. The three
654 machines in play are different. You might want such a toolchain if you
655 have a fast build machine, but the users will use it on another machine,
656 and will produce code to run on a third machine.
657 crosstool-NG calls it "canadian".
659 crosstool-NG can build all these kinds of toolchains (or is aiming at it,
662 (*) The term Canadian Cross came about because at the time that these issues
663 were all being hashed out, Canada had three national political parties.
664 http://en.wikipedia.org/wiki/Cross_compiler
672 Sending a bug report |
673 ---------------------+
675 If you need to send a bug report, please send a mail with subject
676 prefixed with "[CT_NG]" with to following destinations:
677 TO: yann.morin.1998 (at) anciens.enib.fr
678 CC: crossgcc (at) sourceware.org
683 If you want to enhance crosstool-NG, there's a to-do list in the TODO file.
685 Patches should come with the appropriate SoB line. A SoB line is typically
687 Signed-off-by: John DOE <john.doe@somewhere.net>
689 The SoB line is clearly described in Documentation/SubmittingPatches , section
690 12, of your favourite Linux kernel source tree.
693 How to Use Mercurial |
694 ---------------------+
696 For larger or more frequent contributions, mercurial should be used.
700 Configuring Mercurial:
701 You need mercurial with the following extensions:
702 - mq : http://mercurial.selenic.com/wiki/MqExtension
703 - patchbomb : http://mercurial.selenic.com/wiki/PatchbombExtension
704 Usually, these two extensions are already part of the installation package.
705 The mq extension maintains a separate queue of your local changes
706 that you can change at any later time.
707 With the patchbomb extension you can email those patches directly
708 from your local repo.
710 Your configuration file for mercurial, e.g. ~/.hgrc should contain
711 at least the following sections (but have a look at `man hgrc`):
714 # configure sending patches directly via Mercurial
715 from = "Your Name" <your@email.address>
720 # SMTP configuration (only for method=smtp)
727 # The following lines enable the two extensions:
732 Create your local repository as a clone:
733 hg clone http://ymorin.is-a-geek.org/hg/crosstool-ng crosstool-ng
735 Setting up the mq extension in your local copy:
742 Recording your changes in the patch queue maintained by mq:
743 # First, create a new patch entry in the patch queue:
744 hg qnew -D -U -e short_patch_name1
745 <edit patch description as commit message (see below for an example)>
747 <now edit the ct-ng sources and check them>
749 # if you execute `hg status` here, your modifications of the working
750 # copy should show up.
752 # Now the following command takes your modifications from the working copy
753 # into the patch entry
755 <reedit patch description [-e] if desired>
757 # Now your changes are recorded, and `hg status` should show a clean
760 Repeat the above steps for all your modifications.
761 The command `hg qseries` informs you about the content of your patch queue.
764 CONTRIBUTING YOUR PATCHES:
766 Once you are satisfied with your patch series, you can (you should!)
767 contribute them back to upstream.
768 This is easily done using the `hg email` command.
770 `hg email` sends your new changesets to a specified list of recipients,
771 each patch in its own email, all ordered in the way you entered them (oldest
772 first). The command line flag --outgoing selects all changesets that are in
773 your local but not yet in the upstream repository. Here, these are exactly
774 the ones you entered into your local patch queue in the section above, so
775 --outgoing is what you want.
777 Each email gets the subject set to: "[PATCH x of n] <series summary>"
778 where 'x' is the serial number in the email series, and 'n' is the total number
779 of patches in the series. The body of the email is the complete patch, plus
780 a handful of metadata, that helps properly apply the patch, keeping the log
781 message, attribution and date, tracking file changes (move, delete, modes...)
783 `hg email` also threads all outgoing patch emails below an introductory
784 message. You should use the introductory message (command line flag --intro)
785 to describe the scope and motivation for the whole patch series. The subject
786 for the introductory message gets set to: "[PATCH 0 of n] <series summary>"
787 and you get the chance to set the <series summary>.
789 Here is a sample `hg email` complete command line:
790 Note: replace " (at) " with "@"
792 hg email --outgoing --intro \
793 --to '"Yann E. MORIN" <yann.morin.1998 (at) anciens.enib.fr>' \
794 --cc 'crossgcc (at) sourceware.org'
796 # It then opens an editor and lets you enter the subject
797 # and the body for the introductory message.
799 Use `hg email` with the additional command line switch -n to
800 first have a look at the email(s) without actually sending them.
803 MAINTAINING YOUR PATCHES:
805 When the patches are refined by discussing them on the mailing list,
806 you may want to finalize and resend them.
808 The mq extension has the idiosyncrasy of imposing a stack onto the queue:
809 You can always reedit/refresh only the patch on top of stack.
810 The queue consists of applied and unapplied patches
811 (if you reached here via the above steps, all of your patches are applied),
812 where the 'stack' consists of the applied patches, and 'top of stack'
813 is the latest applied patch.
815 The following output of `hg qseries` is now used as an example:
816 0 A short_patch_name1
817 1 A short_patch_name2
818 2 A short_patch_name3
819 3 A short_patch_name4
821 You are now able to edit patch 'short_patch_name4' (which is top of stack):
825 <and optionally [-e] reedit the commit message>
827 If you want to edit e.g. patch short_patch_name2, you have to modify
828 mq's stack so this patch gets top of stack.
829 For this purpose see `hg help qgoto`, `hg help qpop`, and `hg help qpush`.
831 hg qgoto short_patch_name2
832 # The patch queue should now look like
834 0 A short_patch_name1
835 1 A short_patch_name2
836 2 U short_patch_name3
837 3 U short_patch_name4
838 # so patch # 1 (short_patch_name2) is top of stack.
839 <now reedit the sources for short_patch_name2>
842 <and optionally [-e] reedit the commit message>
843 # the following command reapplies the now unapplied two patches:
845 # you can also use `hg qgoto short_patch_name4` to get there again.
848 RESENDING YOUR REEDITED PATCHES:
850 By mailing list policy, please resend your complete patch series.
851 --> Go back to section "CONTRIBUTING YOUR PATCHES" and resubmit the full set.
854 SYNCING WITH UPSTREAM AGAIN:
856 You can sync your repo with upstream at any time by executing
857 # first unapply all your patches:
859 # next fetch new changesets from upstream
861 # then update your working copy
863 # optionally remove already upstream integrated patches (see below)
864 hg qdelete <short_name_of_already_applied_patch>
865 # and reapply your patches if any non upstream-integrated left (but see below)
868 Eventually, your patches get included into the upstream repository
869 which you initially cloned.
870 In this case, before executing the hg qpush -a from above
871 you should manually "hg qdelete" the patches that are already integrated upstream.
874 HOW TO FORMAT COMMIT MESSAGES (aka patch desciptions):
876 Commit messages should look like (without leading pipes):
877 |component: short, one-line description
879 |optional longer description
880 |on multiple lines if needed
882 Here is an example commit message (see revision a53a5e1d61db):
883 |comp-libs/cloog: fix building
885 |For CLooG/PPL 0.15.3, the directory name was simply cloog-ppl.
886 |For any later versions, the directory name does have the version, such as
894 Internally, crosstool-NG is script-based. To ease usage, the frontend is
900 The entry point to crosstool-NG is the Makefile script "ct-ng". Calling this
901 script with an action will act exactly as if the Makefile was in the current
902 working directory and make was called with the action as rule. Thus:
905 is equivalent to having the Makefile in CWD, and calling:
908 Having ct-ng as it is avoids copying the Makefile everywhere, and acts as a
911 ct-ng loads sub- Makefiles from the library directory $(CT_LIB_DIR), as set up
912 at configuration time with ./configure.
914 ct-ng also searches for config files, sub-tools, samples, scripts and patches in
915 that library directory.
917 Because of a stupid make behavior/bug I was unable to track down, implicit make
918 rules are disabled: installing with --local would triger those rules, and mconf
924 The kconfig language is a hacked version, vampirised from the Linux kernel
925 (http://www.kernel.org/), and (heavily) adapted to my needs.
927 The list of the most notable changes (at least the ones I remember) follows:
928 - the CONFIG_ prefix has been replaced with CT_
929 - a leading | in prompts is skipped, and subsequent leading spaces are not
930 trimmed; otherwise leading spaces are silently trimmed
931 - removed the warning about undefined environment variable
933 The kconfig parsers (conf and mconf) are not installed pre-built, but as
934 source files. Thus you can have the directory where crosstool-NG is installed,
935 exported (via NFS or whatever) and have clients with different architectures
936 use the same crosstool-NG installation, and most notably, the same set of
939 Architecture-specific |
940 ----------------------+
942 Note: this chapter is not really well written, and might thus be a little bit
943 complex to understand. To get a better grasp of what an architecture is, the
944 reader is kindly encouraged to look at the "arch/" sub-directory, and to the
945 existing architectures to see how things are laid out.
947 An architecture is defined by:
949 - a human-readable name, in lower case letters, with numbers as appropriate.
950 The underscore is allowed; space and special characters are not.
952 - a file in "config/arch/", named after the architecture's name, and suffixed
954 Eg.: config/arch/arm.in
955 - a file in "scripts/build/arch/", named after the architecture's name, and
957 Eg.: scripts/build/arch/arm.sh
959 The architecture's ".in" file API:
960 > the config option "ARCH_%arch%" (where %arch% is to be replaced with the
961 actual architecture name).
962 That config option must have *neither* a type, *nor* a prompt! Also, it can
963 *not* depend on any other config option (EXPERIMENTAL is managed as above).
967 defines a (terse) help entry for this architecture:
971 The ARM architecture.
973 selects adequate associated config options.
974 Note: 64-bit architectures *shall* select ARCH_64
977 select ARCH_SUPPORTS_BOTH_ENDIAN
978 select ARCH_DEFAULT_LE
980 The ARM architecture.
985 The x86_64 architecture.
987 > other target-specific options, at your discretion. Note however that to
988 avoid name-clashing, such options shall be prefixed with "ARCH_%arch%",
989 where %arch% is again replaced by the actual architecture name.
990 (Note: due to historical reasons, and lack of time to clean up the code,
991 I may have left some config options that do not completely conform to
992 this, as the architecture name was written all upper case. However, the
993 prefix is unique among architectures, and does not cause harm).
995 The architecture's ".sh" file API:
996 > the function "CT_DoArchTupleValues"
999 - all variables from the ".config" file,
1000 - the two variables "target_endian_eb" and "target_endian_el" which are
1001 the endianness suffixes
1002 + return value: 0 upon success, !0 upon failure
1005 - the environment variable CT_TARGET_ARCH
1007 the architecture part of the target tuple.
1008 Eg.: "armeb" for big endian ARM
1012 - the environment variable CT_TARGET_SYS
1014 the sytem part of the target tuple.
1015 Eg.: "gnu" for glibc on most architectures
1016 "gnueabi" for glibc on an ARM EABI
1018 - for glibc-based toolchain: "gnu"
1019 - for uClibc-based toolchain: "uclibc"
1022 - the environment variables to configure the cross-gcc (defaults)
1023 - CT_ARCH_WITH_ARCH : the gcc ./configure switch to select architecture level ( "--with-arch=${CT_ARCH_ARCH}" )
1024 - CT_ARCH_WITH_ABI : the gcc ./configure switch to select ABI level ( "--with-abi=${CT_ARCH_ABI}" )
1025 - CT_ARCH_WITH_CPU : the gcc ./configure switch to select CPU instruction set ( "--with-cpu=${CT_ARCH_CPU}" )
1026 - CT_ARCH_WITH_TUNE : the gcc ./configure switch to select scheduling ( "--with-tune=${CT_ARCH_TUNE}" )
1027 - CT_ARCH_WITH_FPU : the gcc ./configure switch to select FPU type ( "--with-fpu=${CT_ARCH_FPU}" )
1028 - CT_ARCH_WITH_FLOAT : the gcc ./configure switch to select floating point arithmetics ( "--with-float=soft" or /empty/ )
1031 - the environment variables to pass to the cross-gcc to build target binaries (defaults)
1032 - CT_ARCH_ARCH_CFLAG : the gcc switch to select architecture level ( "-march=${CT_ARCH_ARCH}" )
1033 - CT_ARCH_ABI_CFLAG : the gcc switch to select ABI level ( "-mabi=${CT_ARCH_ABI}" )
1034 - CT_ARCH_CPU_CFLAG : the gcc switch to select CPU instruction set ( "-mcpu=${CT_ARCH_CPU}" )
1035 - CT_ARCH_TUNE_CFLAG : the gcc switch to select scheduling ( "-mtune=${CT_ARCH_TUNE}" )
1036 - CT_ARCH_FPU_CFLAG : the gcc switch to select FPU type ( "-mfpu=${CT_ARCH_FPU}" )
1037 - CT_ARCH_FLOAT_CFLAG : the gcc switch to choose floating point arithmetics ( "-msoft-float" or /empty/ )
1038 - CT_ARCH_ENDIAN_CFLAG : the gcc switch to choose big or little endian ( "-mbig-endian" or "-mlittle-endian" )
1043 - the environement variables to configure the core and final compiler, specific to this architecture:
1044 - CT_ARCH_CC_CORE_EXTRA_CONFIG : additional, architecture specific core gcc ./configure flags
1045 - CT_ARCH_CC_EXTRA_CONFIG : additional, architecture specific final gcc ./configure flags
1050 - the architecture-specific CFLAGS and LDFLAGS:
1051 - CT_ARCH_TARGET_CLFAGS
1052 - CT_ARCH_TARGET_LDFLAGS
1056 You can have a look at "config/arch/arm.in" and "scripts/build/arch/arm.sh" for
1057 a quite complete example of what an actual architecture description looks like.
1062 A kernel is defined by:
1064 - a human-readable name, in lower case letters, with numbers as appropriate.
1065 The underscore is allowed; space and special characters are not (although
1066 they are internally replaced with underscores.
1067 Eg.: linux, bare-metal
1068 - a file in "config/kernel/", named after the kernel name, and suffixed with
1070 Eg.: config/kernel/linux.in, config/kernel/bare-metal.in
1071 - a file in "scripts/build/kernel/", named after the kernel name, and suffixed
1073 Eg.: scripts/build/kernel/linux.sh, scripts/build/kernel/bare-metal.sh
1075 The kernel's ".in" file must contain:
1076 > an optional lines containing exactly "# EXPERIMENTAL", starting on the
1077 first column, and without any following space or other character.
1078 If this line is present, then this kernel is considered EXPERIMENTAL,
1079 and correct dependency on EXPERIMENTAL will be set.
1081 > the config option "KERNEL_%kernel_name%" (where %kernel_name% is to be
1082 replaced with the actual kernel name, with all special characters and
1083 spaces replaced by underscores).
1084 That config option must have *neither* a type, *nor* a prompt! Also, it can
1085 *not* depends on EXPERIMENTAL.
1086 Eg.: KERNEL_linux, KERNEL_bare_metal
1088 defines a (terse) help entry for this kernel.
1090 config KERNEL_bare_metal
1092 Build a compiler for use without any kernel.
1094 selects adequate associated config options.
1096 config KERNEL_bare_metal
1099 Build a compiler for use without any kernel.
1101 > other kernel specific options, at your discretion. Note however that, to
1102 avoid name-clashing, such options should be prefixed with
1103 "KERNEL_%kernel_name%", where %kernel_name% is again tp be replaced with
1104 the actual kernel name.
1105 (Note: due to historical reasons, and lack of time to clean up the code,
1106 I may have left some config options that do not completely conform to
1107 this, as the kernel name was written all upper case. However, the prefix
1108 is unique among kernels, and does not cause harm).
1110 The kernel's ".sh" file API:
1111 > is a bash script fragment
1113 > defines the function CT_DoKernelTupleValues
1114 + see the architecture's CT_DoArchTupleValues, except for:
1115 + set the environment variable CT_TARGET_KERNEL, the kernel part of the
1117 + return value: ignored
1119 > defines the function "do_kernel_get":
1122 - all variables from the ".config" file.
1123 + return value: 0 for success, !0 for failure.
1124 + behavior: download the kernel's sources, and store the tarball into
1125 "${CT_TARBALLS_DIR}". To this end, a functions is available, that
1126 abstracts downloading tarballs:
1127 - CT_DoGet <tarball_base_name> <URL1 [URL...]>
1128 Eg.: CT_DoGet linux-2.6.26.5 ftp://ftp.kernel.org/pub/linux/kernel/v2.6
1129 Note: retrieving sources from svn, cvs, git and the likes is not supported
1130 by CT_DoGet. You'll have to do this by hand, as it is done for eglibc in
1131 "scripts/build/libc/eglibc.sh"
1133 > defines the function "do_kernel_extract":
1136 - all variables from the ".config" file,
1137 + return value: 0 for success, !0 for failure.
1138 + behavior: extract the kernel's tarball into "${CT_SRC_DIR}", and apply
1139 required patches. To this end, a function is available, that abstracts
1140 extracting tarballs:
1141 - CT_ExtractAndPatch <tarball_base_name>
1142 Eg.: CT_ExtractAndPatch linux-2.6.26.5
1144 > defines the function "do_kernel_headers":
1147 - all variables from the ".config" file,
1148 + return value: 0 for success, !0 for failure.
1149 + behavior: install the kernel headers (if any) in "${CT_SYSROOT_DIR}/usr/include"
1151 > defines any kernel-specific helper functions
1152 These functions, if any, must be prefixed with "do_kernel_%CT_KERNEL%_",
1153 where '%CT_KERNEL%' is to be replaced with the actual kernel name, to avoid
1156 You can have a look at "config/kernel/linux.in" and "scripts/build/kernel/linux.sh"
1157 as an example of what a complex kernel description looks like.
1159 Adding a new version of a component |
1160 ------------------------------------+
1162 When a new component, such as the Linux kernel, gcc or any other is released,
1163 adding the new version to crosstool-NG is quite easy. There is a script that
1164 will do all that for you:
1165 scripts/addToolVersion.sh
1167 Run it with no option to get some help.
1172 To Be Written later...