Free Compilers and Cross-Compilers
for Linux and Windows.

Yesterday's release of gcc, version 4.3.0, was a shock. The compilation of the Fortran compiler failed. The compilation of the Win32 (mingw32) cross compiler failed. This was incredibly shoddy for a major release. I imagined people having significant problems figuring what was going on, so, I wrote this article to try and help out. Of course, in this article, I will not use version 4.3.0, but its immediate predecessor, version 4.2.3.

Well, it turns out that both of these problems go away, if you do the build in directories separate from the sources. Since this is non-traditional, it might have been nice for people to point out that the build will not work, in certain cases, unless you build in separate directories. For projects like gcc, compiling in separate directories is actually a great idea.

Although the original problems with 4.3.0 have been solved, I ran into more difficulties later in the program, so, at least for the time being, I have stuck with version 4.2.3. Below, I have repeated the original program using separate build directories. If you do this, all the compilers and cross-compilers, are able to compile, at least, C, C++, Fortran and Java code. I made no attempt to incorporate ADA into the mix.

This is an outline of what we will do:

(1) compile a C,C++,Java,Fortran,ObjC,ObjC++,treelang compiler for Linux
(2) compile a C cross-compiler for Linux (needed to compile system libraries)
(3) compile a C,C++,Java,Fortran,ObjC,ObjC++ cross-compiler for Linux
(4) compile a C,C++,Java,Fortran,ObjC,ObjC++ compiler for Windows
(5) compile a C,C++,Java,Fortran cross-compiler for Windows

Compiler (1) runs on a Linux box and produces binaries that will run under Linux
Compiler (3) runs on a Linux box and produces binaries that will run under Windows
Compiler (4) runs on a Windows box and produces binaries that will run under Windows
Compiler (5) runs on a Windows box and produces binaries that will run under Linux

I have recently added some extra sections:

(6) How to use the Cross-Compiler(s) you built in step 3.
(7) Adding the language ADA to the mix.
(8) Using the Compiler(s) you built in step 1.
(9) General Remarks.

Make sure that you have the following programs and packages installed.

For SuSE 10.0: gcc libgcc glibc glibc-devel glib2 glib2-devel ncurses ncurses-devel gcc-c++ libstdc++ libstdc++-devel.

For Debian: emacs21 bzip2 gcc libncurses5-dev libc6-dev libc6-dev-i386 lib32gcc1 g++ libstdc++6-4.1-dev (and gnat if you want ADA).

You may also need to install autoconf and automake.

You will need at least 5 Gigabytes of free space. The compilation of part (1) took nearly 4 hours. The rest took just under 2 hours.

Download the following to the directory /gcc/:

binutils-2.18.50.tar.bz2 (16M)
gcc-4.2.3.tar.bz2 (43M) from www.gnu.org/

You can also obtain gcc-4.2.3.tar.bz2 in smaller pieces. Note, that in order to compile the ADA compiler, you need a working ADA compiler (GNAT 3.14, or later) on your system.

You need the following Win32 API and runtime files:

w32api-3.11-src.tar.gz
mingw-runtime-3.14-src.tar.gz from www.mingw.org

By the way, mingw.org exists to mislead and hinder, rather than help.

It is best to upgrade your version of gmp and mpfr:

mpfr-2.3.1.tar.bz2 from www.mpfr.org
gmp-4.2.2.tar.bz2 from gmplib.org

It is assumed that you are the root user.

(1) Compile a C,C++,Java,Fortran,ObjC,ObjC++,treelang compiler for Linux.

We do this to have an up-to-date compiler (actually, a collection of compilers) with which to compile the cross-compilers of steps 2 and 3. Beginning with an older compiler can lead to some complications. I did the build on a SuSE 10.0 Linux box. Using the installed compiler (version 4.0.2) worked for all steps except parts of (4) and all of (5). Using version 4.2.3 means that most things work.

Save all the packages to the directory /gcc/. Go there and unpack everything:

(unpacks everything)

The make install script runs the command ldconfig -n /usr/local/lib. It turns out that this is not sufficient, you need to run ldconfig (as root). This updates the ld.so.cache file so that it knows to use the newly installed gmp library, rather than some older, pre-existing, gmp library. In particular, you want the compilation of the mpfr library to use the correct version of gmp.

Similarly, if you have some pre-existing version of the mpfr library, then you need to run ldconfig again. You should probably run ldconfig again, in any case, just to be on the safe side.

So that version 4.2.3 does not interfere with your older installed compiler, it will be installed in /usr/local/. To use it, instead of the installed compiler, you need to have /usr/local/bin first on your path. You arrange this with:

(2) Compile a C cross-compiler for Linux.

This C cross-compiler will run on your Linux system and create binaries, from Linux C code, that will run on a Windows system. We need to use this cross-compiler to compile the Win32 API and runtime libraries.

The files in /usr/local/i686-pc-mingw32, will be used for cross-compiling Linux programs to run on Windows.

(3) Compile a C,C++,Java,Fortran,ObjC,ObjC++ cross-compiler for Linux.

The C cross-compiler is compiled again, along with the other languages. This cross-compiler is run on your Linux box and compiles binaries, from Linux code, that will run on a Windows system. That is, it compiles Linux source code, so that the resulting binaries will run, unaltered, on Windows.

Know you need to run ldconfig to tell all the other programs where to find the necessary libraries:

(4) Compile a C,C++,Java,Fortran,ObjC,ObjC++ compiler for Windows.

This compiler is a native Windows compiler. That is, it runs on a Windows box. It compiles Windows source code and the resulting binaries will run on Windows. When compiling C++, this compiler will do the same job as Visual C++ or C++ Builder.

The configure script expects to find the system headers and libraries in /mingw, so we have arranged for them to be there.

The reason for the second installs into /mingw, is that the libtool libraries, i.e., the .la files, have their destination directory hard-coded into them, so you can not simply copy them from /usr/local/i686-pc-mingw32/lib to /mingw/lib.

The files that end up in /mingw will be transfered to C:\mingw on your Windows box.

(5) Compile a C,C++,Java,Fortran cross-compiler for Windows.

This compiler runs on a Windows box. It compiles Windows source code and the resulting binaries will run unaltered on Linux. Ever wanted to compile VirtualDub so that it runs on Linux? This avoids having to port the source code.

Now you copy everything in /mingw to C:\mingw on a Windows box and start compiling there. After you have compiled your Windows program, say VirtualDub, on your Windows computer, you transfer the resulting executable back to Linux and run it there. Of course, for most compilations you will also need to compile a version of the make program for Windows. You can compile the make program for Windows, on your Linux box, by using the cross-compiler you built in step (3).

(6) How to use the cross-compiler you built in step 3.

As a quick example of how to use the cross-compiler you built in step 3. Download the Linux make program to /gcc/:

make-3.81.tar.bz2 from www.gnu.org/

Now copy make.exe to C:\mingw\bin on your Windows box. Easy, isn't it?

(7) Adding the language ADA to the mix.

Download the following binary gnat package to /gcc/:

gnat-3.15p-i686-pc-redhat71-gnu-bin.tar.bz2 (12M) from linuxfromscratch.org

Run the script doconfig entering /gcc/gnat for the installation directory. Then run doinstall.

Follow the instructions of section (1), until the compilation of the compiler itself.

Then set your PATH variable so that you use the ADA-understanding compiler that you have just installed.

Now compile the compiler of section (1), with one small change. Namely, add ada to the --enable-languages option.

Then reset you PATH variable and continue from section (2), as above, except adding ada to the --enable-languages option.

You could also try the compiler in gnat-gpl-2007-i686-gnu-linux-libc2.3-bin.tar.gz (75M) from libre.adacore.com. Unfortunately, gcc-4.2.3 does not compile at all and gcc-4.3.0 does not compile outside the sources.

If at any time you need to know which compiler you are using, just enter the command:

Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /gcc/gcc-4.2.3/configure --enable-languages=c,ada,c++,fortran,java,objc,obj-c++,treelang
Thread model: posix
gcc version 4.2.3

The compiler in the gnat package is gcc version 2.8.1. Ancient, but worked like a charm.

(8) Using the Compiler you built in step 1.

The first thing to note, is that the "obvious" and do not work.

The Fortran front-end is gfortran. It is used as also works.

The Java front-end is gcj. The following incantations can be used to compile Java code:

(compile to C++ object file, a.out)
(execute the C++ object file, a.out)
(compile to Java bytecode file, program.class)
(execute the bytecode, program.class, with the GCC Java Virtual Machine)

To compile ObjC code, use If you mix ObjC code and C++ code in the same files, you call the resulting mixture, ObjC++ code. It is apparently compiled in the same way as ObjC code. You are totally on your own for treelang.

To compile ADA code, use (9) General Remarks.

Since it is difficult to cut and paste many of the above commands, here is the script I used for the project.

If you are building on an older PC, replace i686 by i386, everywhere in the above.

For AMD-64, the script config.guess, gives x86_64-unknown-linux-gnu. It seems you can put any word in place of unknown, or no word at all. So configure with something like:

I actually used x86_64-pc-linux-gnu and am assuming that x86_64-linux-gnu will work.

If you have a multilib system, like Debian, you may want to compile both 32-bit and 64-bit libraries for gcc. You need to have all the standard 32-bit libraries installed. On Debian, make sure you have the links:

The compilation will fail, for gcc-4.2.3, unless you use the --disable-multilib configuration option, or you create the (secret) link:

For gcc-4.3.0 the above link appears to be unnecessary (4.3.0 has other problems).

I have been running short on space and over time have deleted all my Windows partitions. As soon as I get around to reinstalling Windows, I will let you know how the Windows compilers work. I have now done this. There are weird problems with the Fortran compiler and the Java Virtual Machine, gij, is mysteriously missing. C C++ ObjC and ObjC++ seem OK, at least for simple programs. The compilers were run from an XP cmd window. I only looked at the native Windows compilers. I will look at the cross compilers at some later date.

By the way, if you wish to both watch, and record, the output of the compilation, you can do this:

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