[POST] Added instructions for cross-compiling binutils for Windows

Author: jameswalmsley

_posts/2014-07-01-build-arm-gcc-toolchain-for-windows.md

@@ -0,0 +1,262 @@
+---
+layout: posts
+title: Building GCC / GNU Toolchain for Windows
+author: James Walmsley
+author_email: [email protected]
+category: misc
+---
+
+I've been trying to sucessfully compile GCC for Windows to allow me to maintain a Windows version of the BTDK
+(BitThunder development kit). Well the documentation on the internet describing how to do this is thin and far between.
+The good news is that I've finally managed to create one.
+
+# Strategies
+Most guides talk about setting up MSYS and MinGW or cygwin or some other native Windows build environment. I explicitly do NOT
+recommend this approach. Its extremely slow and tedious, you will simply waste months of your life!
+
+The approach I eventually settled for is to cross-compile for Windows on Linux (Ubuntu 14.10). To do this I use the excellent MXE
+cross compile environment.
+
+The build involves the following steps:
+
+1. Clone and build MXE.
+2. Configure build environment.
+3. Clone and build binutils-gdb
+4. Download and build libgmp (4.3.2)
+5. Download and build libmpfr (2.4.2)
+6. Download and build libmpc (0.8.1)
+7. Clone and build gcc (stage 1).
+8. Clone and build newlib.
+9. Clone build gcc (final stage).
+
+## 1. Get and Install MXE
+
+{% highlight bash %}
+git clone git://github.com/mxe/mxe.git
+cd mxe
+git checkout stable
+make
+{% endhighlight %}
+
+Now wait for a really long time... You don't actually need the whole environment to be built, but it will come in useful.
+
+## 2. Build Variables & Environment
+
+    PATH   : Path must include the mxe binary path:
+{% highlight bash %}
+export PATH=/path/to/mxe/usr/bin:$PATH
+{% endhighlight %}
+
+    TARGET	    : This is the target type, e.g. arm-unknown-eabi or arm-eabi-bt
+	PREFIX      : Where the toolchain will reside on the system. E.g. /opt/btdk
+	HOST        : The type of system that will host the compiler (Windows in our case).
+	BUILD       : The type of system that is being used to build the toolchain.
+	PKGVERSION  : A toolchain package name/version.
+
+	BTDK uses the following defaults:
+
+{% highlight bash %}
+export TARGET=arm-unknown-eabi
+export PREFIX=/opt/mytoolchain
+export HOST=i686-pc-mingw32
+export BUILD="$(config.guess)"
+export PKGVERSION="mytoolchain v1.0.0"
+{% endhighlight %}
+
+## 3. Building Binutils (ld gas nm gdb etc)
+
+{% highlight bash %}
+git clone git://sourceware.org/git/binutils-gdb.git
+mkdir build-binutils
+cd build-binutils
+../binutils-gdb/configure --host=${HOST} --build=${BUILD} --target=${TARGET} \
+                          --prefix=${PREFIX} --enable-interwork --enable-multilib \
+                          --enable-target-optspace --with-float=soft --disable-werror \
+                          --with-pkgversion=${PKGVERSION}
+make
+sudo make install
+{% endhighlight %}
+
+### Patch / Fix for Binutils
+Currently the build tree contains a fix for compiling for windows, but MXE is good enough not to need it.
+If the build complains something like:
+
+{% highlight bash %}
+mxe/usr/lib/gcc/i686-pc-mingw32/4.8.1/../../../../i686-pc-mingw32/lib/libncurses.a(lib_tputs.o):lib_tputs.c:(.text+0x780): multiple definition of `tputs'
+windows-termcap.o:mytoolchain/binutils-gdb/gdb/windows-termcap.c:62: first defined here
+{% endhighlight %}
+
+The simply open the file gdb/windows-termcap.c
+
+Comment out the tputs() function, or apply the following patch:
+
+{% highlight bash %}
+diff --git a/gdb/windows-termcap.c b/gdb/windows-termcap.c
+index 7c258cf..e7d5fa3 100644
+--- a/gdb/windows-termcap.c
++++ b/gdb/windows-termcap.c
+@@ -57,14 +57,14 @@ tgetstr (char *name, char **area)
+   return NULL;
+ }
+
+-int
++/*int
+ tputs (char *string, int nlines, int (*outfun) ())
+ {
+   while (*string)
+     outfun (*string++);
+
+   return 0;
+-}
++}*/
+
+ char *
+ tgoto (const char *cap, int col, int row)
+{% endhighlight %}
+
+You can apply it by saving it into a .patch file and ...
+
+{% highlight bash %}
+cd ../binutils-gdb
+git apply binutils.patch
+cd ../build-binutils
+make
+sudo make install
+{% endhighlight %}
+
+There's also a problem with the install target, of binutils it cannot find the ranlib tool for some reason. You can fix this with the following patch:
+
+{% highlight bash %}
+# Obviously adjust the path to your actual mxe ranlib binary :D
+sed -i 's:i686-pc-mingw32-ranlib:/home/wl/develop/tools/mxe/usr/bin/i686-pc-mingw32-ranlib:g' Makefile sim/Makefile sim/arm/Makefile
+sudo make install
+{% endhighlight %}
+
+You should now have a full gdb and binutils for windows:
+
+{% highlight bash %}
+tree ${PREFIX}/bin/
+/opt/mytoolchain/bin/
+├── arm-unknown-eabi-addr2line.exe
+├── arm-unknown-eabi-ar.exe
+├── arm-unknown-eabi-as.exe
+├── arm-unknown-eabi-c++filt.exe
+├── arm-unknown-eabi-elfedit.exe
+├── arm-unknown-eabi-gdb.exe
+├── arm-unknown-eabi-gprof.exe
+├── arm-unknown-eabi-ld.bfd.exe
+├── arm-unknown-eabi-ld.exe
+├── arm-unknown-eabi-nm.exe
+├── arm-unknown-eabi-objcopy.exe
+├── arm-unknown-eabi-objdump.exe
+├── arm-unknown-eabi-ranlib.exe
+├── arm-unknown-eabi-readelf.exe
+├── arm-unknown-eabi-run.exe
+├── arm-unknown-eabi-size.exe
+├── arm-unknown-eabi-strings.exe
+└── arm-unknown-eabi-strip.exe
+
+0 directories, 18 files
+{% endhighlight %}
+
+## 4. Build libgmp
+Yup building these libraries is boring, but its probably the safest option in the long run
+(trust me I wasted hours of my life trying to make this all link with pre-compiled versions in mingw32, mxe is probably better
+but lets just use my working method :D )
+
+{% highlight bash %}
+wget https://gmplib.org/download/gmp/gmp-4.3.2.tar.bz2
+tar xvf gmp-4.3.2.tar.bz2
+mkdir build-gmp
+cd build-gmp
+../gmp-4.3.2/configure --host=${HOST} --build=${BUILD} --prefix=$(pwd)/../libgmp \
+                       --disable-shared --enable-static --without-readline --enable-cxx
+make
+# We install into ../libgmp/ so we don't need sudo.
+make install
+{% endhighlight %}
+
+## 5. Build libmpfr
+
+{% highlight bash %}
+wget https://ftp.gnu.org/gnu/mpfr/mpfr-2.4.2.tar.bz2
+tar xvf mpfr-2.4.2.tar.bz2
+mkdir build-mpfr
+cd build-mpfr
+../mpfr-2.4.2/configure --host=${HOST} --build=${BUILD} --prefix=$(pwd)/../libmpfr \
+                        --with-gmp=$(pwd)/../libgmp --disable-shared --enable-static
+make
+make check
+make install
+{% endhighlight %}
+
+## 6. Build libmpc
+{% highlight bash %}
+wget http://www.multiprecision.org/mpc/download/mpc-0.8.1.tar.gz
+tar xvf mpc-0.8.1.tar.gz
+mkdir build-mpc
+cd build-mpc
+../mpc-0.8.1/configure --host=${HOST} --build=${BUILD} --prefix=$(pwd)/../libmpc \
+                       --with-gmp=$(pwd)/../libgmp --with-mpfr=$(pwd)/../libmpfr \
+                       --disable-shared --enable-static
+make
+make install
+{% endhighlight %}
+
+## 7. Build GCC - Stage 1
+
+Building GCC for Windows is the most complex part of this cross-compile.
+
+{% highlight bash %}
+git clone git://gcc.gnu.org/git/gcc.git
+cd gcc
+git checkout gcc-4_9_0-release
+mkdir build-gcc
+cd build-gcc
+../gcc/configure --host=${HOST} --build=${BUILD} --target=${TARGET} --prefix=${PREFIX} \
+                 --enable-interwork --enable-multilib --enable-languages="c" \
+                 --with-newlib --without-headers --disable-shared --disable-libssp \
+                 --with-gnu-as --with-gnu-ld --disable-nls \
+                 --with-pkgversion=${PKGVERSION} --with-gmp=$(pwd)/../libgmp \
+                 --with-mpfr=$(pwd)/../libmpfr --with-mpc=$(pwd)/../libmpc
+make all-gcc
+sudo make install-gcc
+#make all-target-libgcc             # Cannot build using the Windows compiler in Wine on linux.
+#sudo make install-target-libgcc    # Solution is to copy the libraries produced when building the toolchain for linux.
+{% endhighlight %}
+
+You'll find that at this point building libgcc and libstdc++ etc will actually fail. I finally realised that actually it doesn't matter
+from this point on. You don't actually need to compile anything further with the Windows toolchain at this point.
+
+Simply use the libraries as compiled by your native linux cross compiler, and copy them into your windows cross-compiler appropriately.
+
+### Fixes or Patches for GCC 4.9.0
+
+Currently you'll probably get a cannot find arm-unknown-eabi-gcc error when the build system attempts to dump the compiler
+specs. To work around this, you can apply the following patch:
+
+{% highlight bash %}
+sed -i 's:$(GCC_FOR_TARGET) -dumpspecs > tmp-specs:./xgcc$(exeext) -dumpspecs > tmp-specs:g' gcc/Makefile
+make all-gcc
+sudo make install-gcc
+make all-target-libgcc
+sudo make install-target-libgcc
+{% endhighlight %}
+
+At this stage you should have a working cross-compiler. As long as you don't use any standard libraries at all, then you can
+build a working kernel. In fact you should be able to use such a compiler to build BitThunder.
+
+You can even use this compiler to build your own libc and then manually link with it.
+
+For most purposes a basic libc is useful, and its really convenient to use e.g. the BTDK which uses a ported version of
+newlib to provide a complete libc implementation on top of bitthunder.
+
+## 8. Build Newlib
+
+Again the secret is to simply copy the libraries produced by linux to the Windows toolchain folders.
+
+## 9. Finalise GCC.
+
+Not 100% sure what this stage does. I think it creates a arm-eabi-bt/bin/gcc.exe etc. In anycase I don't think they are needed,
+and you can always copy the bin/arm-eabi-bt-gcc.exe files to the appropriate place manually.
+