File.........: B - Known issues.txt

Copyrigth....: (C) 2010 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>

License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5

Known issues  /

_____________/

This files lists the known issues encountered while developping crosstool-NG,

but that could not be addressed before the release.

The file has one section for each known issue, each section containing four

sub-sections: Symptoms, Explanations, Fix, and Workaround.

Each section is separated from the others with a lines of at least 4 dashes.

The following dummy section explains it all.

    --------------------------------

    Symptoms:

      A one-liner of what you would observe.

    Explanations:

      An as much as possible in-depth explanations of the context, why it

      happens, what has been investigated so far, and possible orientations

      as how to try to solve this (eg. URLs, code snippets...).

    Fix:

      What you have to do to fix it, if at all possible.

      The fact that there is a fix, and yet this is a known issue means that

      time to incorporate the fix in crosstool-NG was missing, or planned for

      a future release.

    Workaround:

      What you can do to fix it *temporarily*, if at all possible.

      A workaround is not a real fix, as it can break other parts of

      crosstool-NG, but at least makes you going in your particular case.

So now, on for the real issues...

--------------------------------

Symptoms:

  gcc is not found, although I *do* have gcc installed.

Explanations:

  This is an issue on at least RHEL systems, where gcc is a symlink to ccache.

  Because crosstool-NG create links to gcc for the build and host environment,

  those symlinks are in fact pointing to ccache, which then doesn't know how

  to run the compiler.

  A possible fix could probably set the environment variable CCACHE_CC to the

  actual compiler used.

Fix:

  None known.

Workaround:

  Uninstall ccache.

--------------------------------

Symptoms:

  The extract and/or path steps fail under Cygwin.

Explanations:

  This is not related to crosstool-NG. Mounts under Cygwin are by default not

  case-sensitive. You have to use so-called "managed" mounts. See:

  http://cygwin.com/faq.html section 4, question 32.

Fix:

  Use "managed" mounts for the directories where you build *and* install your

  toolchains.

Workaround:

  None.

--------------------------------

Symptoms:

  uClibc fails to build under Cygwin.

Explanations:

  With uClibc, it is possible to build a cross-ldd. Unfortunately, it is

  not (currently) possible to build this cross-ldd under Cygwin.

Fix:

  None so far.

Workaround:

  Disable the cross-ldd build.

--------------------------------

Symptoms:

  On 64-bit build systems, the glibc (possibly eglibc too) build fails for

  64-bit targets, because it can not find libgcc.

Explanations:

  This issue has been observed when the companion libraries are built

  statically. For an unknown reason, in this case, the libgcc built by the

  core gcc is not located in the same place it is located when building

  with shared companion libraries.

Fix:

  None so far.

Workaround:

  Build shared companion libraries.

--------------------------------

Symptoms:

  While building the final gcc, I get an error message that ends with:

    libtool.m4: error: problem compiling FC test program

Explanations:

  The gcc build procedure tries to run a Fortran test to see if it has a

  working native fortran compiler installed on the build machine, and it

  can't find one. A native Fortran compiler is needed (seems to be neede)

  to build the Fortran frontend of the cross-compiler.

  Even if you don't want to build the Fortran frontend, gcc tries to see

  if it has one, but fails. This is no problem, as the Fortran frontend

  will not be built. There is nothing to be worry about (unless you do

  want to build the Fortran frontend, of course).

Fix:

  None so far. It's a spurious error, so there will probably never be

  a fix for this issue.

Workaround:

  None needed, it's a spurious error.

--------------------------------

Symptoms:

  gcc barfs because it is "unable to detect the exception model".

Explanations:

  On some architectures, proper stack unwinding (C++) requires that

  setjmp/longjmp (sjlj) be used, while on other architectures do not

  need sjlj. On some architectures, gcc is unable to determine whether

  sjlj are needed or not.

Fix:

  None so far.

Workaround:

  Trying setting use of sjlj to either 'Y' or 'N' (instead of the

  default 'M') in the menuconfig, option CT_CC_GCC_SJLJ_EXCEPTIONS

  labelled "Use sjlj for exceptions".

--------------------------------