274 lines
8 KiB
Plaintext
274 lines
8 KiB
Plaintext
Setting up a cross compiler with Nix
|
|
|
|
"Cross compilation" means compiling a program on one machine for another
|
|
type of machine. A typical use of cross compilation is to compile programs
|
|
for embedded devices. These devices often don't have the computing power
|
|
and memory to compile programs natively.
|
|
|
|
For a fully working cross compiler the following are needed:
|
|
|
|
* cross binutils: assembler, archiver, linker, etcetera that understand
|
|
the format of the target system
|
|
|
|
* cross compiler: a compiler that can generate binary code and object files
|
|
for the target platform
|
|
|
|
* cross C library: a library to link object files with to create fully
|
|
functional programs
|
|
|
|
Cross compilers are difficult to set up. A lot of people report that they
|
|
cannot succeed in building a cross toolchain successfully. The answers
|
|
usually consist of "download this pre-built toolchain", which is equally
|
|
unhelpful.
|
|
|
|
A toolchain is set up in five steps:
|
|
|
|
1. build binutils to that can run on the host platform, but generate code
|
|
for the target platform
|
|
|
|
2. build Linux kernel headers for the target platform
|
|
|
|
3. build a minimal C only version of GCC, that can run on the host platform
|
|
and generate code for the target platform
|
|
|
|
4. build a C library for the target platform. This includes the dynamic
|
|
linker, C library, etc.
|
|
|
|
5. build a full GCC
|
|
|
|
****
|
|
NB:
|
|
|
|
Keep in mind that many programs are not very well suited for cross
|
|
compilation. Either they are not intended to run on other platforms,
|
|
because the code is highly platform specific, or the configuration proces
|
|
is not written with cross compilation in mind.
|
|
|
|
Nix will not solve these problems for you!
|
|
***
|
|
|
|
This document describes to set up a cross compiler to generate code for
|
|
arm-linux with uClibc and runs on i686-linux. The "stdenv" used is the
|
|
default from the standard Nix packages collection.
|
|
|
|
Step 1: build binutils for arm-linux in the stdenv for i686-linux
|
|
|
|
---
|
|
{stdenv, fetchurl, noSysDirs}:
|
|
|
|
stdenv.mkDerivation {
|
|
name = "binutils-2.16.1-arm";
|
|
builder = ./builder.sh;
|
|
src = fetchurl {
|
|
url = http://ftp.nluug.nl/gnu/binutils/binutils-2.16.1.tar.bz2;
|
|
md5 = "6a9d529efb285071dad10e1f3d2b2967";
|
|
};
|
|
inherit noSysDirs;
|
|
configureFlags = "--target=arm-linux";
|
|
}
|
|
---
|
|
|
|
This will compile binutils that will run on i686-linux, but knows the
|
|
format used by arm-linux.
|
|
|
|
Step 2: build kernel headers for the target architecture
|
|
|
|
default.nix for kernel-headers-arm:
|
|
|
|
---
|
|
{stdenv, fetchurl}:
|
|
|
|
assert stdenv.system == "i686-linux";
|
|
|
|
stdenv.mkDerivation {
|
|
name = "linux-headers-2.6.13.4-arm";
|
|
builder = ./builder.sh;
|
|
src = fetchurl {
|
|
url = http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.13.4.tar.bz2;
|
|
md5 = "94768d7eef90a9d8174639b2a7d3f58d";
|
|
};
|
|
}
|
|
---
|
|
|
|
builder.sh for kernel-headers-arm:
|
|
|
|
---
|
|
source $stdenv/setup
|
|
|
|
|
|
buildPhase() {
|
|
make include/linux/version.h
|
|
}
|
|
|
|
buildPhase=buildPhase
|
|
|
|
|
|
installPhase() {
|
|
mkdir $out
|
|
mkdir $out/include
|
|
#cd $out/include
|
|
#ln -s asm-arm asm
|
|
make include/asm ARCH=arm
|
|
cp -prvd include/linux include/asm include/asm-arm include/asm-generic $out/include
|
|
echo -n > $out/include/linux/autoconf.h
|
|
}
|
|
|
|
installPhase=installPhase
|
|
|
|
|
|
genericBuild
|
|
---
|
|
|
|
Step 3: build a minimal GCC
|
|
|
|
Extra/different parameters include the target platform and the kernel
|
|
headers argument (this needs a major cleanup, as well as the name, it
|
|
needs to be different!). Profiled compilers are disabled. The tarball
|
|
used here is just gcc-core. For some reason it doesn't install nicely
|
|
if the whole tarball is used (or is this some braino on my side? -- AH).
|
|
|
|
Only C is used, because for other languages (such as C++) extra libraries
|
|
need to be compiled, for which libraries compiled for the target system
|
|
are needed.
|
|
|
|
There is a bit of evilness going on. The cross compiled utilities need
|
|
to be either copied to or be linked from the output tree of the compiler.
|
|
(Is this really true? Back this up with arguments! -- AH)
|
|
|
|
Symbolic links are not something we want inside the Nix store.
|
|
|
|
---
|
|
{ stdenv, fetchurl, noSysDirs
|
|
, langC ? true, langCC ? true, langF77 ? false
|
|
, profiledCompiler ? false
|
|
, binutilsArm
|
|
, kernelHeadersArm
|
|
}:
|
|
|
|
assert langC;
|
|
|
|
stdenv.mkDerivation {
|
|
name = "gcc-4.0.2-arm";
|
|
builder = ./builder.sh;
|
|
src = fetchurl {
|
|
url = ftp://ftp.nluug.nl/pub/gnu/gcc/gcc-4.0.2/gcc-core-4.0.2.tar.bz2;
|
|
md5 = "f7781398ada62ba255486673e6274b26";
|
|
#url = ftp://ftp.nluug.nl/pub/gnu/gcc/gcc-4.0.2/gcc-4.0.2.tar.bz2;
|
|
#md5 = "a659b8388cac9db2b13e056e574ceeb0";
|
|
};
|
|
# !!! apply only if noSysDirs is set
|
|
patches = [./no-sys-dirs.patch ./gcc-inhibit.patch];
|
|
inherit noSysDirs langC langCC langF77 profiledCompiler;
|
|
buildInputs = [binutilsArm];
|
|
inherit kernelHeadersArm binutilsArm;
|
|
platform = "arm-linux";
|
|
}
|
|
---
|
|
|
|
|
|
---
|
|
source $stdenv/setup
|
|
|
|
|
|
export NIX_FIXINC_DUMMY=$NIX_BUILD_TOP/dummy
|
|
mkdir $NIX_FIXINC_DUMMY
|
|
|
|
|
|
if test "$noSysDirs" = "1"; then
|
|
|
|
if test "$noSysDirs" = "1"; then
|
|
# Figure out what extra flags to pass to the gcc compilers
|
|
# being generated to make sure that they use our glibc.
|
|
if test -e $NIX_GCC/nix-support/orig-glibc; then
|
|
glibc=$(cat $NIX_GCC/nix-support/orig-glibc)
|
|
# Ugh. Copied from gcc-wrapper/builder.sh. We can't just
|
|
# source in $NIX_GCC/nix-support/add-flags, since that
|
|
# would cause *this* GCC to be linked against the
|
|
# *previous* GCC. Need some more modularity there.
|
|
extraCFlags="-B$glibc/lib -isystem $glibc/include"
|
|
extraLDFlags="-B$glibc/lib -L$glibc/lib -Wl,-s \
|
|
-Wl,-dynamic-linker,$glibc/lib/ld-linux.so.2"
|
|
|
|
# Oh, what a hack. I should be shot for this.
|
|
# In stage 1, we should link against the previous GCC, but
|
|
# not afterwards. Otherwise we retain a dependency.
|
|
# However, ld-wrapper, which adds the linker flags for the
|
|
# previous GCC, is also used in stage 2/3. We can prevent
|
|
# it from adding them by NIX_GLIBC_FLAGS_SET, but then
|
|
# gcc-wrapper will also not add them, thereby causing
|
|
# stage 1 to fail. So we use a trick to only set the
|
|
# flags in gcc-wrapper.
|
|
hook=$(pwd)/ld-wrapper-hook
|
|
echo "NIX_GLIBC_FLAGS_SET=1" > $hook
|
|
export NIX_LD_WRAPPER_START_HOOK=$hook
|
|
fi
|
|
|
|
export NIX_EXTRA_CFLAGS=$extraCFlags
|
|
export NIX_EXTRA_LDFLAGS=$extraLDFlags
|
|
export CFLAGS=$extraCFlags
|
|
export CXXFLAGS=$extraCFlags
|
|
export LDFLAGS=$extraLDFlags
|
|
fi
|
|
|
|
else
|
|
patches=""
|
|
fi
|
|
|
|
|
|
preConfigure=preConfigure
|
|
preConfigure() {
|
|
|
|
# Determine the frontends to build.
|
|
langs="c"
|
|
if test -n "$langCC"; then
|
|
langs="$langs,c++"
|
|
fi
|
|
if test -n "$langF77"; then
|
|
langs="$langs,f77"
|
|
fi
|
|
|
|
# Cross compiler evilness
|
|
ensureDir $out
|
|
ensureDir $out/arm-linux
|
|
ensureDir $out/arm-linux/bin
|
|
ln -s $binutilsArm/arm-linux/bin/as $out/arm-linux/bin/as
|
|
ln -s $binutilsArm/arm-linux/bin/ld $out/arm-linux/bin/ld
|
|
ln -s $binutilsArm/arm-linux/bin/ar $out/arm-linux/bin/ar
|
|
ln -s $binutilsArm/arm-linux/bin/ranlib $out/arm-linux/bin/ranlib
|
|
|
|
# Perform the build in a different directory.
|
|
mkdir ../build
|
|
cd ../build
|
|
|
|
configureScript=../$sourceRoot/configure
|
|
configureFlags="--enable-languages=$langs --target=$platform --disable-threads --disable-libmudflap --disable-shared --with-headers=$kernelHeadersArm/include --disable-multilib"
|
|
}
|
|
|
|
|
|
postInstall=postInstall
|
|
postInstall() {
|
|
# Remove precompiled headers for now. They are very big and
|
|
# probably not very useful yet.
|
|
find $out/include -name "*.gch" -exec rm -rf {} \; -prune
|
|
|
|
# Remove `fixincl' to prevent a retained dependency on the
|
|
# previous gcc.
|
|
rm -rf $out/libexec/gcc/*/*/install-tools
|
|
}
|
|
|
|
|
|
#if test -z "$profiledCompiler"; then
|
|
#makeFlags="bootstrap"
|
|
#else
|
|
#makeFlags="profiledbootstrap"
|
|
#fi
|
|
|
|
genericBuild
|
|
---
|
|
|
|
Step 4: build a C library for the target platform.
|
|
|
|
The previous steps are enough to compile a C library. In our case we take
|
|
uClibc. It's intended to be a small sized replacement for glibc. It is widely
|
|
used in embedded environments.
|