如何在x86上为Sun4v交叉编译GCC？

Question

I am writing a programming assignment using C++. The instructor of this course requires all code to be compiled and run on the UNIX server. The server is a SunOS machine. I wrote all my code on my personal laptop with GCC 5.2, which support most C++11 features. However, when I upload my code to the server and tried to compile it, I surprisingly found that the g++ version on the server is 4.2.1, which was released in mid-2007. Many of the C++11 features are not supported. Even the -std argument is not accepted.

I tried to download the source code of the latest GCC and compile it on the server. Unfortunately there is a disk quota limiting to 500M per account. I am just wondering if it is possible to cross compile GCC on my x86 machine and upload the binary on to the server so that I can compile my C++ code.

By the way, I have contacted the IT department about updating the software but they responded that they do not have such plans in the near future.

I did do research on the Internet about cross compilation and found a couple tutorials. But they are not easy to follow. In addition to binaries, there are also a lot dependencies like headers and libraries. So before I give up and modify my code to fit the old compiler, can anyone give me some suggestions?

Thank you.

uname -a returns the following result

SunOS 5.10 Generic_147147-26 sun4v sparc SUNW,T5240

Answer 1

Of course it's possible, and it's the way you usually do the things when writing operating systems .

First of all, you need to take binutils in the toolbox , too. Once you have all the Holy Sources, let's prepare!

export PREFIX="$HOME/opt" # All the stuff will get installed here!
export TARGET=sparc-sun-solaris  # I'm not *100%* sure if this is correct, check it yourself
export PATH="$PREFIX/bin:$PATH"  # If you forget this/close the terminal, you're doomed!

Now, let's get with the little monster... Shall binutils be built!

cd $HOME/src # Or where you have the sources
mkdir binutils-build
cd binutils-build
../binutils-src/configure --target=$TARGET --prefix="$PREFIX" --disable-nls
make
make install

--disable-nls disables the support for native natural languages (aka: the compiler prints errors in your own language!), and just uses English for messages. That's not a must, but it certainly speeds up the process of building binutils.

Now, compiling GCC itself is a very fragile process, and it can fail anywhere, anyhow, so be prepared! This process is long (it can take up to an hour on some machines), but trust me, LLVM+Clang is worse ;).

cd $HOME/src
cd gcc-src
./contrib/download_prerequisites # Get GMP, MPFR, and MPC
cd ..
mkdir gcc-build
cd gcc-build
../gcc-src/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --enable-languages=c,c++
make all-gcc
make all-target-libgcc
make install-gcc
make install-target-libgcc

If you don't get into issues while compiling (trust me, you will unless you're too lucky for this world), you'll have a toolchain that runs on your machine, but compiles for SunOS/SPARC! BTW, --enable-languages=c,c++ means that GCC will have support for compiling C and C++ code. Nothing less, nothing more. Try it out with...

sparc-sun-solaris-g++ --version

Now, if you want to get a compiler for the server, that runs on the server, you will have to some mess with a double canadian cross . Basically, what you have to do is...

export PREFIX="$HOME/some-holy-directory" # This path *must* be the same for both your machine and the target server!
export HOST=$TARGET

And then repeat the compilation process again, remembering to adding the option --host=$HOST to both configure scripts! Once done, you must move that some-holy-directory at exactly the same location into the server. If it didn't fit into the 500MB, well, ask your teacher if you can at least compile assignments in your own machine, then upload them to the server. Otherwise, you're left out with C++98.

BTW : Please note that cross-compiling GCC itself is an even more fragile process. All this post is just theoretical, because I won't do all this steps just for the sake of doing it. Please comment if you have any major issues, or if someone spots an error in the steps ;).

Edit : Apparently, you'll have to build Glibc and all that funky stuff too...

I hope this has led some light on you!