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c009897aee
Reported-by: "Antony N. Pavlov" <antony@niisi.msk.ru> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
109 lines
5.0 KiB
Plaintext
109 lines
5.0 KiB
Plaintext
File.........: 1 - Introduction.txt
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Copyright....: (C) 2010 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>
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License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5
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Introduction /
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_____________/
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crosstool-NG aims at building toolchains. Toolchains are an essential component
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in a software development project. It will compile, assemble and link the code
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that is being developed. Some pieces of the toolchain will eventually end up
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in the resulting binary/ies: static libraries are but an example.
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So, a toolchain is a very sensitive piece of software, as any bug in one of the
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components, or a poorly configured component, can lead to execution problems,
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ranging from poor performance, to applications ending unexpectedly, to
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mis-behaving software (which more than often is hard to detect), to hardware
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damage, or even to human risks (which is more than regrettable).
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Toolchains are made of different piece of software, each being quite complex
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and requiring specially crafted options to build and work seamlessly. This
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is usually not that easy, even in the not-so-trivial case of native toolchains.
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The work reaches a higher degree of complexity when it comes to cross-
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compilation, where it can become quite a nightmare...
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Some cross-toolchains exist on the internet, and can be used for general
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development, but they have a number of limitations:
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- they can be general purpose, in that they are configured for the majority:
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no optimisation for your specific target,
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- they can be prepared for a specific target and thus are not easy to use,
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nor optimised for, or even supporting your target,
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- they often are using aging components (compiler, C library, etc...) not
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supporting special features of your shiny new processor;
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On the other side, these toolchain offer some advantages:
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- they are ready to use and quite easy to install and setup,
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- they are proven if used by a wide community.
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But once you want to get all the juice out of your specific hardware, you will
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want to build your own toolchain. This is where crosstool-NG comes into play.
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There are also a number of tools that build toolchains for specific needs,
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which are not really scalable. Examples are:
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- buildroot (buildroot.uclibc.org) whose main purpose is to build root file
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systems, hence the name. But once you have your toolchain with buildroot,
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part of it is installed in the root-to-be, so if you want to build a whole
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new root, you either have to save the existing one as a template and
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restore it later, or restart again from scratch. This is not convenient,
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- ptxdist (www.pengutronix.de/software/ptxdist), whose purpose is very
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similar to buildroot,
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- other projects (openembedded.org for example), which are again used to
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build root file systems.
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crosstool-NG is really targeted at building toolchains, and only toolchains.
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It is then up to you to use it the way you want.
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History |
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--------+
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crosstool was first 'conceived' by Dan Kegel, who offered it to the community
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as a set of scripts, a repository of patches, and some pre-configured, general
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purpose setup files to be used to configure crosstool. This is available at
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http://www.kegel.com/crosstool, and the subversion repository is hosted on
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google at http://code.google.com/p/crosstool/.
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I once managed to add support for uClibc-based toolchains, but it did not make
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into mainline, mostly because I didn't have time to port the patch forward to
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the new versions, due in part to the big effort it was taking.
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So I decided to clean up crosstool in the state it was, re-order the things
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in place, add appropriate support for what I needed, that is uClibc support
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and a menu-driven configuration, named the new implementation crosstool-NG,
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(standing for crosstool Next Generation, as many other community projects do,
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and as a wink at the TV series "Star Trek: The Next Generation" ;-) ) and
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made it available to the community, in case it was of interest to any one.
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Referring to crosstool-NG |
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--------------------------+
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The long name of the project is crosstool-NG:
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* no leading uppercase (except as first word in a sentence)
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* crosstool and NG separated with a hyphen (dash)
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* NG in uppercase
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Crosstool-NG can also be referred to by its short name CT-NG:
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* all in uppercase
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* CT and NG separated with a hyphen (dash)
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The long name is preferred over the short name, except in mail subjects, where
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the short name is a better fit.
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When referring to a specific version of crosstool-NG, append the version number
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either as:
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* crosstool-NG X.Y.Z
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- the long name, a space, and the version string
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* crosstool-ng-X.Y.Z
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- the long name in lowercase, a hyphen (dash), and the version string
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- this is used to name the release tarballs
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* crosstool-ng-X.Y.Z+hg_id
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- the long name in lowercase, a hyphen, the version string, and the Hg id
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(as returned by: ct-ng version)
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- this is used to differentiate between releases and snapshots
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The frontend to crosstool-NG is the command ct-ng:
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* all in lowercase
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* ct and ng separated by a hyphen (dash)
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