== C/C++ cross compiler ==

This page contains instructions on how to build a GCC toolchain, which can be used to cross-compile C and C++ applications for Barrelfish.

In general, most language constructs work (libstdc++, RTTI, virtual functions, templates, global constructors, inline assembler, thread locals) but exceptions are not supported (read [[https://lists.inf.ethz.ch/pipermail/barrelfish-users/2013-January/000894.html|here]] for more details).

<<TableOfContents()>>

=== Building (Short Version) ===

First, you will need to install a few packages:
{{{
$ sudo apt-get install gcc g++ make patch bison flex texinfo
}}}

''Optional'': to enable [[http://gcc.gnu.org/wiki/Graphite|Graphite]] loop optimizations you will also need {{{libcloog-ppl-dev}}}.

Next, download the build script and corresponding patches to some folder in your Barrelfish tree (e.g. {{{tools/gcc_cross_compiler}}}):
||<style="background-color: #E0E0FF;">'''build script'''||[[attachment:build-toolchain.sh]]||
||<style="background-color: #E0E0FF;">'''binutils'''||'''[[attachment:binutils-2.24-barrelfish.patch|2.24]]''', [[attachment:binutils-2.21-bf.patch|2.21]]||
||<style="background-color: #E0E0FF;">'''GCC'''||'''[[attachment:gcc-4.8.3-barrelfish.patch|4.9.2]]''', [[attachment:gcc-4.8.3-barrelfish.patch|4.8.3]], [[attachment:gcc-4.7.3-barrelfish.patch|4.7.3]], [[attachment:gcc-4.5.2-bf.patch|4.5.2]]||

The recommended versions (shown in bold) should be preferred as these have been tested and have several improvements and fixes. These are known to work with Barrelfish ''release2014-12-01''.

Finally, modify any configuration parameters in the script, run it and a few minutes later the toolchain should be installed in the ''toolchain'' directory of your Barrelfish tree.

''Hint'': Each toolchain is specific to a build tree, so it can be helpful to use [[http://direnv.net/|direnv]] or [[https://github.com/cxreg/smartcd|smartcd]] to automatically add/remove it from the PATH environment variable.

=== Usage ===
 * For autoconf, add the Barrelfish target triple to {{{config.sub}}}:
 {{{
@@ -1244,6 +1244,7 @@ case $os in
        | -hpux* | -unos* | -osf* | -luna* | -dgux* | -solaris* | -sym* \
        | -amigaos* | -amigados* | -msdos* | -newsos* | -unicos* | -aof* \
        | -aos* \
+       | -barrelfish* \
        | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
        | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
        | -hiux* | -386bsd* | -knetbsd* | -mirbsd* | -netbsd* \
}}}
 ... and run the configure script in cross-compile mode:
 {{{
./configure --host=x86_64-pc-barrelfish
}}}
 * For CMake, you will need a [[http://www.vtk.org/Wiki/CMake_Cross_Compiling#Setting_up_the_system_and_toolchain|toolchain file]] with something like:
 {{{
set(CMAKE_SYSTEM_NAME "Generic")
set(CMAKE_SYSTEM_PROCESSOR "x86_64")
set(TOOLCHAIN_PREFIX_ "${CMAKE_SYSTEM_PROCESSOR}-pc-barrelfish-")
set(CMAKE_C_COMPILER "${TOOLCHAIN_PREFIX_}gcc")
set(CMAKE_CXX_COMPILER "${TOOLCHAIN_PREFIX_}g++")
}}}

From this point, if the application fails to compile it is probably due to missing POSIX features in Barrelfish.

=== Building (Long Version) ===

These instructions have been tested on '''Ubuntu 12.10'''.

1. Edit $HOME/.bashrc and add these lines (modify these variables as you wish):
{{{
 export PREFIX=$HOME/arm/opt/bf-tools
 export PATH=$PATH:$PREFIX/bin
 export TARGET=x86_64-pc-barrelfish
 export TOOLS=$HOME/bsc/bf-tools
 export BF_BUILD=$HOME/arm/bf/build
}}}
 * '''PREFIX''' is where the toolchain will be installed
 * '''TOOLS''' is the initially empty working directory
 * '''BF_BUILD''' is the Barrelfish build directory
 * '''TARGET''' is the cross compiler target. It can be:
  * x86_64-pc-barrelfish
  * i586-pc-barrelfish
  * i586-scc-barrelfish

We exit the shell and run it again to load these variables.

2. Download and build '''Barrelfish''' for '''x86_64''', '''x86_32''' or '''scc''' target (this step may have been done previously). The Barrelfish release tested is '''2012-11-03''':

{{{
cd $TOOLS
git clone git://git.barrelfish.org/git/barrelfish
cd barrelfish
mkdir build
cd build
../hake/hake.sh -a x86_64 -s ..
make
}}}

3. Then, we need to install needed packages to build the toolchain:

{{{
sudo apt-get install texinfo flex gcc libgmp-dev libmpfr-dev libmpc-dev
}}}

These steps have been done using the system compiler (gcc version 4.7.2).

4. Build and install '''binutils''':
Save file ''[[attachment:binutils-2.21-bf.patch]]'' file attached in this page to the '''TOOLS''' directory

{{{
cd $TOOLS
wget http://mirrors.usc.edu/pub/gnu/binutils/binutils-2.21.tar.bz2
tar xjvf binutils-2.21.tar.bz2
cd binutils-2.21/
patch -p1 < ../binutils-2.21-bf.patch
cd ..
mkdir binutils-2.21-build
cd binutils-2.21-build/
../binutils-2.21/configure --prefix=$PREFIX --target=$TARGET
make
make install
}}}

5. Build and install '''gcc''' and '''g++''':
Save file ''[[attachment:gcc-4.5.2-bf.patch]]'' file attached in this page to the '''TOOLS''' directory

{{{
cd $TOOLS
wget http://ftp.gnu.org/gnu/gcc/gcc-4.5.2/gcc-4.5.2.tar.bz2
tar xjvf gcc-4.5.2.tar.bz2
cd gcc-4.5.2/
patch -p1 < ../gcc-4.5.2-bf.patch
}}}

Now we need to edit the files gcc/config/i386/bf-*.h and change the first two lines:
 * '''BF_SRC''' holds the directory of Barrelfish source.
 * '''BF_BUILD''' is the Barrelfish build directory.

Then we proceed with the compilation:

{{{
cd $TOOLS
mkdir gcc-4.5.2-build
cd gcc-4.5.2-build/
../gcc-4.5.2/configure --prefix=$PREFIX --target=$TARGET --disable-nls --enable-languages=c,c++ --disable-libssp
make
make install
}}}

6. We can try the C++ compiler by creating a simple program '''test.cc''' and running it in Barrelfish:

{{{
#include <iostream>

int main(int argc, char *argv[])
{
  std::cout << "Hello!" << std::endl;

  return 0;
}
}}}

We compile it with:

{{{
x86_64-pc-barrelfish-g++ test.cc -o test
}}}

Then we copy the executable to the Barrelfish build directory and add the line to menu.lst:

{{{
cp test $BF_BUILD/x86_64/sbin
cd $BF_BUILD
echo "module /x86_64/sbin/test" >> menu.lst
make sim
}}}