Compiling LLVM 2.9's gcc 4.2 on kernel 3.0 with gcc 4.6

Question

I'm trying to get llvm-gcc 4.2.2.9 to compile on this x86_64 system which runs the 3.0.0-21-generic kernel. llvm 2.9 itself builds fine. I suspected the downloadable version of llvm-gcc was causing some other problems, so I decided to build llvm-gcc myself.

Like suggested in the README.LLVM I configured with

../llvm-gcc-4.2-2.9.source/configure \
  --prefix=/opt/llvm-gcc4.2-2.9/../llvm-gcc4.2-2.9-install \
  --disable-multilib \
  --program-prefix=llvm- \
  --enable-llvm=/opt/llvm-2.9 \
  --host=x86_64-generic-linux-gnu
  --enable-languages=c,c++

I'm running this from the /opt/llvm-gcc4.2-2.9 directory, while the sources are sitting in /opt/llvm-gcc-4.2-2.9.source and my llvm 2.9 lives in /opt/llvm-2.9. Note that I'm setting the --host instead of the --target as this implicitly sets the --target to the same architecture.

make does build a lot of stuff (producing a sizeable amount of warnings) when finally stopping at this error:

make[3]: Entering directory `/opt/llvm-gcc4.2-2.9/gcc'
/opt/llvm-gcc4.2-2.9/./gcc/xgcc -B/opt/llvm-gcc4.2-2.9/./gcc/ -B/opt/llvm-gcc4.2-2.9/../llvm-gcc4.2-2.9-install/x86_64-generic-linux-gnu/bin/ -B/opt/llvm-gcc4.2-2.9/../llvm-gcc4.2-2.9-install/x86_64-generic-linux-gnu/lib/ -isystem /opt/llvm-gcc4.2-2.9/../llvm-gcc4.2-2.9-install/x86_64-generic-linux-gnu/include -isystem /opt/llvm-gcc4.2-2.9/../llvm-gcc4.2-2.9-install/x86_64-generic-linux-gnu/sys-include  -O2 -O2 -g -O2  -DIN_GCC    -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -I. -I. -I../../llvm-gcc-4.2-2.9.source/gcc -I../../llvm-gcc-4.2-2.9.source/gcc/. -I../../llvm-gcc-4.2-2.9.source/gcc/../include -I../../llvm-gcc-4.2-2.9.source/gcc/../libcpp/include  -I../../llvm-gcc-4.2-2.9.source/gcc/../libdecnumber -I../libdecnumber -I/opt/llvm-2.9/include  -g0 -finhibit-size-directive -fno-inline-functions -fno-exceptions -fno-zero-initialized-in-bss -fno-toplevel-reorder  -fno-omit-frame-pointer -fno-asynchronous-unwind-tables \
      -c ../../llvm-gcc-4.2-2.9.source/gcc/crtstuff.c -DCRT_BEGIN \
      -o crtbegin.o
In file included from /usr/include/stdio.h:28,
                 from ../../llvm-gcc-4.2-2.9.source/gcc/tsystem.h:90,
                 from ../../llvm-gcc-4.2-2.9.source/gcc/crtstuff.c:68:
/usr/include/features.h:323:26: error: bits/predefs.h: No such file or directory
/usr/include/features.h:356:25: error: sys/cdefs.h: No such file or directory
/usr/include/features.h:388:23: error: gnu/stubs.h: No such file or directory

I find it a bit odd that the include path goes from my system's stdio.h back to llvm-gcc headers and then tries again to include system headers. But maybe that's normal?

After that error hundreds of lines with more errors follow from the same compilation unit.

Could it be that my system's gcc 4.6.1 or my system's headers maybe grew incompatible with the dated llvm-gcc 4.2 headers? Then again, I know that on a different system (running the 2.6 kernel) gcc 4.5.2 plays well with llvm 2.7's gcc 4.2.

I'm at a loss here, because I do need a recent llvm 2.*, and the other two acceptable llvm versions (2.7, 2.8) didn't show any result more helpful.

Maybe a stupid question, but did you try llvm-3.0 or llvm-3.1 with clang? — Benjamin Bannier
@honk: I didn't. Mainly for the reason that I woudn't have any use for llvm >= 3.0. I need llvm-gcc and llvm 2.9 (or 8 or 7). — bitmask

Anton Korobeynikov Anton Korobeynikov · Accepted Answer · 2012-06-17T16:41:02

It seems that /usr/include on your system provides 32-bit headers, thus the compilation fails since you do not have all multilib headers installed. You might need to patch llvm-gcc the same way as your distribution patches gcc in order to find the headers locations.

Alternatively, you might try to install 32-bit headers and try multilib build of llvm-gcc.

But the best way will be switch to LLVM 3.1 and clang :)

Compiling LLVM 2.9's gcc 4.2 on kernel 3.0 with gcc 4.6

1 Answers