[GRASS-dev] Re: [GRASS GIS] #50: g.copy segfaults (debian.gfoss.it package) [and latest SVN]

[GRASS GIS]

#50: g.copy segfaults (debian.gfoss.it package) [and latest SVN]
----------------------+-----------------------------------------------------
  Reporter:  steko    |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect   |      Status:  new                      
  Priority:  major    |   Milestone:  6.4.0                    
 Component:  default  |     Version:  6.3.0 RCs                
Resolution:           |    Keywords:  g.copy                   
----------------------+-----------------------------------------------------
Comment (by dylan):

 Some updates:

 Glyn says that this can only really be debugged by looking at assembly.
 Since I cannot do that, another approach might be toggling various
 optimization flags in order to get an idea of what may be causing the
 segfault. Below are some details on my system / optimization flags /
 results.

 GCC details:

 {{{
 gcc -v
 Using built-in specs.
 Target: i486-linux-gnu
 Configured with: ../src/configure -v --enable-
 languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-
 shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext
 --enable-threads=posix --enable-nls --with-gxx-include-
 dir=/usr/include/c++/4.1.3 --program-suffix=-4.1 --enable-__cxa_atexit
 --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --with-
 tune=i686 --enable-checking=release i486-linux-gnu
 Thread model: posix
 gcc version 4.1.3 20070601 (prerelease) (Debian 4.1.2-12)
 }}}

 compile flags that cause a segfault:
 -O3 (probably segfault)
 -O2 (segfault)
 -O1 (or) -O (segfault)
 -O0 (works as expected)

 The actual CFLAGS for no optimization were: {{{export
 CFLAGS="-march=opteron -O0 -ggdb -Wall -Werror-implicit-function-
 declaration" ; export CXXFLAGS="-march=opteron -O0" ./configure ...}}} .


 So it is probably one of these flags that is causing the optimization-
 related segfault:
 {{{
 -fauto-inc-dec
           -fcprop-registers
           -fdce
           -fdefer-pop
           -fdelayed-branch
           -fdse
           -fguess-branch-probability
           -fif-conversion2
           -fif-conversion
           -finline-small-functions
           -fipa-pure-const
           -fipa-reference
           -fmerge-constants
           -fsplit-wide-types
           -ftree-ccp
           -ftree-ch
           -ftree-copyrename
           -ftree-dce
           -ftree-dominator-opts
           -ftree-dse
           -ftree-fre
           -ftree-sra
           -ftree-ter
           -funit-at-a-time
 }}}

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/50#comment:4>
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