docs/B - Known issues.txt
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Thu Apr 07 19:17:12 2011 +0200 (2011-04-07)
changeset 2386 ff33dccf005c
parent 2384 5f260bb27b35
child 2387 41743d7a3f37
permissions -rw-r--r--
docs: use the error message in the known issues titles

This helps users find the appropriate known issue entry.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
yann@2076
     1
File.........: B - Known issues.txt
yann@2076
     2
Copyrigth....: (C) 2010 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>
yann@2076
     3
License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5
yann@2076
     4
yann@2076
     5
yann@2076
     6
Known issues  /
yann@2076
     7
_____________/
yann@2076
     8
yann@2076
     9
yann@2076
    10
This files lists the known issues encountered while developping crosstool-NG,
yann@2076
    11
but that could not be addressed before the release.
yann@2076
    12
yann@2076
    13
The file has one section for each known issue, each section containing four
yann@2076
    14
sub-sections: Symptoms, Explanations, Fix, and Workaround.
yann@2076
    15
yann@2076
    16
Each section is separated from the others with a lines of at least 4 dashes.
yann@2076
    17
yann@2076
    18
The following dummy section explains it all.
yann@2076
    19
yann@2076
    20
    --------------------------------
yann@2076
    21
    Symptoms:
yann@2386
    22
      A one- or two-liner of what you would observe.
yann@2386
    23
      Usually, the error message you would see in the build logs.
yann@2076
    24
yann@2076
    25
    Explanations:
yann@2076
    26
      An as much as possible in-depth explanations of the context, why it
yann@2076
    27
      happens, what has been investigated so far, and possible orientations
yann@2076
    28
      as how to try to solve this (eg. URLs, code snippets...).
yann@2076
    29
yann@2076
    30
    Fix:
yann@2076
    31
      What you have to do to fix it, if at all possible.
yann@2076
    32
      The fact that there is a fix, and yet this is a known issue means that
yann@2076
    33
      time to incorporate the fix in crosstool-NG was missing, or planned for
yann@2076
    34
      a future release.
yann@2076
    35
yann@2076
    36
    Workaround:
yann@2076
    37
      What you can do to fix it *temporarily*, if at all possible.
yann@2076
    38
      A workaround is not a real fix, as it can break other parts of
yann@2076
    39
      crosstool-NG, but at least makes you going in your particular case.
yann@2076
    40
yann@2076
    41
So now, on for the real issues...
yann@2076
    42
yann@2076
    43
--------------------------------
yann@2076
    44
Symptoms:
yann@2076
    45
  gcc is not found, although I *do* have gcc installed.
yann@2076
    46
yann@2076
    47
Explanations:
yann@2076
    48
  This is an issue on at least RHEL systems, where gcc is a symlink to ccache.
yann@2076
    49
  Because crosstool-NG create links to gcc for the build and host environment,
yann@2076
    50
  those symlinks are in fact pointing to ccache, which then doesn't know how
yann@2076
    51
  to run the compiler.
yann@2076
    52
yann@2076
    53
  A possible fix could probably set the environment variable CCACHE_CC to the
yann@2076
    54
  actual compiler used.
yann@2076
    55
yann@2076
    56
Fix:
yann@2076
    57
  None known.
yann@2076
    58
yann@2076
    59
Workaround:
yann@2076
    60
  Uninstall ccache.
yann@2076
    61
yann@2076
    62
--------------------------------
yann@2076
    63
Symptoms:
yann@2076
    64
  The extract and/or path steps fail under Cygwin.
yann@2076
    65
yann@2076
    66
Explanations:
yann@2076
    67
  This is not related to crosstool-NG. Mounts under Cygwin are by default not
yann@2076
    68
  case-sensitive. You have to use so-called "managed" mounts. See:
yann@2076
    69
  http://cygwin.com/faq.html section 4, question 32.
yann@2076
    70
yann@2076
    71
Fix:
yann@2076
    72
  Use "managed" mounts for the directories where you build *and* install your
yann@2076
    73
  toolchains.
yann@2076
    74
yann@2076
    75
Workaround:
yann@2076
    76
  None.
yann@2076
    77
yann@2076
    78
--------------------------------
yann@2076
    79
Symptoms:
yann@2076
    80
  uClibc fails to build under Cygwin.
yann@2076
    81
yann@2076
    82
Explanations:
yann@2076
    83
  With uClibc, it is possible to build a cross-ldd. Unfortunately, it is
yann@2076
    84
  not (currently) possible to build this cross-ldd under Cygwin.
yann@2076
    85
yann@2076
    86
Fix:
yann@2076
    87
  None so far.
yann@2076
    88
yann@2076
    89
Workaround:
yann@2076
    90
  Disable the cross-ldd build.
yann@2076
    91
yann@2076
    92
--------------------------------
yann@2076
    93
Symptoms:
yann@2076
    94
  On 64-bit build systems, the glibc (possibly eglibc too) build fails for
yann@2076
    95
  64-bit targets, because it can not find libgcc.
yann@2076
    96
yann@2076
    97
Explanations:
yann@2076
    98
  This issue has been observed when the companion libraries are built
yann@2076
    99
  statically. For an unknown reason, in this case, the libgcc built by the
yann@2076
   100
  core gcc is not located in the same place it is located when building
yann@2076
   101
  with shared companion libraries.
yann@2076
   102
yann@2076
   103
Fix:
yann@2076
   104
  None so far.
yann@2076
   105
yann@2076
   106
Workaround:
yann@2076
   107
  Build shared companion libraries.
yann@2076
   108
yann@2076
   109
--------------------------------
yann@2076
   110
Symptoms:
yann@2386
   111
  libtool.m4: error: problem compiling FC test program
yann@2076
   112
yann@2076
   113
Explanations:
yann@2076
   114
  The gcc build procedure tries to run a Fortran test to see if it has a
yann@2076
   115
  working native fortran compiler installed on the build machine, and it
yann@2076
   116
  can't find one. A native Fortran compiler is needed (seems to be neede)
yann@2076
   117
  to build the Fortran frontend of the cross-compiler.
yann@2076
   118
  Even if you don't want to build the Fortran frontend, gcc tries to see
yann@2076
   119
  if it has one, but fails. This is no problem, as the Fortran frontend
yann@2076
   120
  will not be built. There is nothing to be worry about (unless you do
yann@2076
   121
  want to build the Fortran frontend, of course).
yann@2076
   122
yann@2076
   123
Fix:
yann@2076
   124
  None so far. It's a spurious error, so there will probably never be
yann@2076
   125
  a fix for this issue.
yann@2076
   126
yann@2076
   127
Workaround:
yann@2076
   128
  None needed, it's a spurious error.
yann@2076
   129
yann@2076
   130
--------------------------------
yann@2076
   131
Symptoms:
yann@2386
   132
  unable to detect the exception model
yann@2076
   133
yann@2076
   134
Explanations:
yann@2076
   135
  On some architectures, proper stack unwinding (C++) requires that
yann@2076
   136
  setjmp/longjmp (sjlj) be used, while on other architectures do not
yann@2076
   137
  need sjlj. On some architectures, gcc is unable to determine whether
yann@2076
   138
  sjlj are needed or not.
yann@2076
   139
yann@2076
   140
Fix:
yann@2076
   141
  None so far.
yann@2076
   142
yann@2076
   143
Workaround:
yann@2076
   144
  Trying setting use of sjlj to either 'Y' or 'N' (instead of the
yann@2076
   145
  default 'M') in the menuconfig, option CT_CC_GCC_SJLJ_EXCEPTIONS
yann@2076
   146
  labelled "Use sjlj for exceptions".
yann@2076
   147
yann@2076
   148
--------------------------------
yann@2384
   149
Symptoms:
yann@2386
   150
  configure: error: forced unwind support is required
yann@2384
   151
yann@2384
   152
Explanations:
yann@2384
   153
  The issue seems to be related to building NPTL on old versions
yann@2384
   154
  of glibc (and possibly eglibc as well) on some architectures
yann@2384
   155
  (seen on powerpc, s390, s390x and x86_64).
yann@2384
   156
yann@2384
   157
Fix:
yann@2384
   158
  None so far. It would require some glibc hacking.
yann@2384
   159
yann@2384
   160
Workaround:
yann@2384
   161
  Try setting "Force unwind support" in the "C-library" menu.
yann@2384
   162
yann@2384
   163
--------------------------------