View source for GDC/Cross Compiler/crosstool-NG

{{ParentArticle|[[GDC]] > [[GDC/Cross Compiler|Cross Compiler]]}} 

== First things first ==
=== Read the crosstool-NG website ===
Have a look at http://www.crosstool-ng.org/  and see if crosstool-NG fits you needs (Architecture, C library, OS, ...).

=== Install crosstool-NG ===
Download crosstool-NG from http://www.crosstool-ng.org/ . Install as described on it's homepage.

=== Read the documentation ===
crosstool-NG includes some useful documentation in it's source tarball. Have a look at the "docs" directory.

=== Build a C cross compiler ===
Before even trying to build a D cross compiler, built a C cross compiler with the desired configuration. Creating cross compilers is difficult, so you should first get a simple C compiler working before trying to build D.

== Obtaining GDC sources ==
=== Checkout GDC ===
First clone the git repository. We'll use the gdc-4.7 branch.

<syntaxhighlight lang="bash">
mkdir -p gdc/dev
git clone https://github.com/D-Programming-GDC/GDC.git gdc/dev
cd gdc/dev
git checkout gdc-4.7
cd ../
</syntaxhighlight>
=== Get GCC sources ===
Grab GCC sources from a mirror. You will need the full gcc archives. Unpack the archives in the gdc dir. This creates something like gdc/gcc-4.7.1. If you want to keep the original GCC sources, rename the gcc-4.7.1 tarball.

=== Patch GCC sources ===
<syntaxhighlight lang="bash">
cd gdc/dev
./update-gcc.sh ../gcc-4.7.1
cd ../
</syntaxhighlight>

=== Package GCC sources ===
We'll now package the GCC sources again, so we'll have a ready to use GCC '''gcc-4.7.1.tar.bz2''' source tarball with the GDC sources included.

<syntaxhighlight lang="bash">
tar -hcjf gcc-4.7.1.tar.bz2 gcc-4.7.1/
</syntaxhighlight>

== Configure crosstool-NG for D ==
We assume you already have a configuration for your target system which produces a working C compiler so you only need to add D support.

=== Make crosstool-NG use our patched sources ===
Start '''ct-ng menuconfig'''. Select '''Paths and misc options''', '''Local tarballs directory''' and enter the path to the directory which contains the patched GCC sources: ''/home/jpf/gdc''. Also make sure '''Try features marked as EXPERIMENTAL''' is set. Select '''C compiler''' in the main menu and make sure '''GCC version''' is set to '''4.7.1'''

=== Enable D language ===
Go to '''C compiler''', select '''Other languages''' and enter '''d'''

=== Disabling druntime & phobos ===
If druntime & phobos do not yet compile for your target you can disable them:

Start ct-ng menuconfig, go to "C compiler" and add "--disable-libphobos" to "Core gcc extra config" and "gcc extra config".

== Build the cross compiler ==
We have to make sure crosstool-NG uses our new sources instead of reusing already extracted or downloaded sources. So if you've already built a plain C cross compiler in your working directory, you'll have to delete the extracted / downloaded sources:

<syntaxhighlight lang="bash">
rm .build/src/.gcc-4.7.1.extracted
rm .build/src/.gcc-4.7.1.patched
rm .build/tarballs/gcc-4.7.1.tar.bz2
rm -rf .build/src/gcc-4.7.1
</syntaxhighlight>

=== Build it ===
<syntaxhighlight lang="bash">
ct-ng build
</syntaxhighlight>