[Buildroot] [PATCH 1/4] manual: convert existing documentation to the asciidoc format

Yann E. MORIN yann.morin.1998 at anciens.enib.fr
Thu Sep 29 21:57:50 UTC 2011


Thomas, All,

On Thursday 29 September 2011 22:05:58 Thomas Petazzoni wrote:
[--SNIP--]
> diff --git a/docs/manual/external-toolchain.txt b/docs/manual/external-toolchain.txt
> new file mode 100644
> index 0000000..3a5b011
> --- /dev/null
> +++ b/docs/manual/external-toolchain.txt
> @@ -0,0 +1,84 @@
> +Using an external toolchain
> +===========================
[--SNIP--]
> +* Use a completely custom external toolchain. This is particularly
> +  useful for toolchains generated using Crosstool-NG. To do this,

Nit-picking, but crosstool-NG does not take a inital capital.

> +  select the +Custom toolchain+ solution in the +Toolchain+ list. You
> +  need to fill the +Toolchain path+, +Toolchain prefix+ and +External
> +  toolchain C library+ options. Then, you have to tell Buildroot what
> +  your external toolchain supports. If your external toolchain uses
> +  the 'glibc' library, you only have to tell whether your toolchain
> +  supports C++ or not. If your external toolchain uses the 'uclibc'
> +  library, then you have to tell Buildroot if it supports largefile,
> +  IPv6, RPC, wide-char, locale, program invocation, threads and
> +  C++. At the beginning of the execution, Buildroot will tell you if
> +  the selected options do not match the toolchain configuration.
> +
> +
> +Our external toolchain support has been tested with toolchains from
> +CodeSourcery, toolchains generated by
> +http://ymorin.is-a-geek.org/dokuwiki/projects/crosstool[Crosstool-NG],

http://crosstool-ng.org[crosstool-NG]

> +and toolchains generated by Buildroot itself. In general, all
> +toolchains that support the 'sysroot' feature should work. If not, do
> +not hesitate to contact the developers.
> +
> +We do not support toolchains from the
> +http://www.denx.de/wiki/DULG/ELDK[ELDK] of Denx, for two reasons:
> +
> +* The ELDK does not contain a pure toolchain (i.e just the compiler,
> +  binutils, the C and C++ libraries), but a toolchain that comes with
> +  a very large set of pre-compiled libraries and programs. Therefore,
> +  Buildroot cannot import the 'sysroot' of the toolchain, as it would
> +  contain hundreds of megabytes of pre-compiled libraries that are
> +  normally built by Buildroot.
> +
> +* The ELDK toolchains have a completely non-standard custom mechanism
> +  to handle multiple library variants. Instead of using the standard
> +  GCC 'multilib' mechanism, the ARM ELDK uses different symbolic links
> +  to the compiler to differentiate between library variants (for ARM
> +  soft-float and ARM VFP), and the PowerPC ELDK compiler uses a
> +  +CROSS_COMPILE+ environment variable. This non-standard behaviour
> +  makes it difficult to support ELDK in Buildroot.
> +
> +We also do not support using the distribution toolchain (i.e the
> +gcc/binutils/C library installed by your distribution) as the
> +toolchain to build software for the target. This is because your
> +distribution toolchain is not a "pure" toolchain (i.e only with the
> +C/C++ library), so we cannot import it properly into the Buildroot
> +build environment. So even if you are building a system for a x86 or
> +x86_64 target, you have to generate a cross-compilation toolchain with
> +Buildroot or Crosstool-NG.

crosstool-NG

Reviewed-by: "Yann E. MORIN" <yann.morin.1998 at anciens.enib.fr>

Regards,
Yann E. MORIN.

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