crosstool-ng/docs/5 - Using the toolchain.txt
Yann E. MORIN" a211f4100d docs: split into multiple files
The overview.txt file has evolved into more than just an overview.
Split it into chapters, and include the misc tutorials.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
2010-08-14 16:37:11 +02:00

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File.........: 5 - Using the toolchain.txt
Copyrigth....: (C) 2010 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>
License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5
Using the toolchain /
____________________/
Using the toolchain is as simple as adding the toolchain's bin directory in
your PATH, such as:
export PATH="${PATH}:/your/toolchain/path/bin"
and then using the target tuple to tell the build systems to use your
toolchain:
./configure --target=your-target-tuple
or
make CC=your-target-tuple-gcc
or
make CROSS_COMPILE=your-target-tuple-
and so on...
It is strongly advised not to use the toolchain sys-root directory as an
install directory for your programs/packages. If you do so, you will not be
able to use your toolchain for another project. It is even strongly advised
that your toolchain is chmod-ed to read-only once successfully build, so that
you don't go polluting your toolchain with your programs/packages' files.
Thus, when you build a program/package, install it in a separate directory,
eg. /your/root. This directory is the /image/ of what would be in the root file
system of your target, and will contain all that your programs/packages have
installed.
The 'populate' script |
----------------------+
When your root directory is ready, it is still missing some important bits: the
toolchain's libraries. To populate your root directory with those libs, just
run:
your-target-tuple-populate -s /your/root -d /your/root-populated
This will copy /your/root into /your/root-populated, and put the needed and only
the needed libraries there. Thus you don't polute /your/root with any cruft that
would no longer be needed should you have to remove stuff. /your/root always
contains only those things you install in it.
You can then use /your/root-populated to build up your file system image, a
tarball, or to NFS-mount it from your target, or whatever you need.
The populate script accepts the following options:
-s src_dir
Use 'src_dir' as the un-populated root directory.
-d dst_dir
Put the populated root directory in 'dst_dir'.
-l lib1 [...]
Always add specified libraries.
-L file
Always add libraries listed in 'file'.
-f
Remove 'dst_dir' if it previously existed; continue even if any library
specified with -l or -L is missing.
-v
Be verbose, and tell what's going on (you can see exactly where libs are
coming from).
-h
Print the help.
See 'your-target-tuple-populate -h' for more information on the options.
Here is how populate works:
1) performs some sanity checks:
- src_dir and dst_dir are specified
- src_dir exists
- unless forced, dst_dir does not exist
- src_dir != dst_dir
2) copy src_dir to dst_dir
3) add forced libraries to dst_dir
- build the list from -l and -L options
- get forced libraries from the sysroot (see below for heuristics)
- abort on the first missing library, unless -f is specified
4) add all missing libraries to dst_dir
- scan dst_dir for every ELF files that are 'executable' or
'shared object'
- list the "NEEDED Shared library" fields
- check if the library is already in dst_dir/lib or dst_dir/usr/lib
- if not, get the library from the sysroot
- if it's in sysroot/lib, copy it to dst_dir/lib
- if it's in sysroot/usr/lib, copy it to dst_dir/usr/lib
- in both cases, use the SONAME of the library to create the file
in dst_dir
- if it was not found in the sysroot, this is an error.