segfault in tcl examples

[pat1]

cd simple_ex1
make do
../simulavr.tcl -d at90s8515 -f fred.elf
-W 0x20,- -R 0x22,- -T exit
make: *** [do] Segmentation fault (core dumped)

compiling with -g and using core file in gdb:
Core was generated by `/usr/bin/tclsh ../simulavr.tcl -d at90s8515 -f fred.elf'.
Program terminated with signal 11, Segmentation fault.
#0 0x000000000008b0d6 in Tcl_GetVar@plt ()

Missing separate debuginfos, use: debuginfo-install glibc-2.17-20.fc19.x86_64 libgcc-4.8.2-7.fc19.x86_64 libstdc++-4.8.2-7.fc19.x86_64 tcl-8.5.14-1.fc19.x86_64 zlib-1.2.7-10.fc19.x86_64
(gdb) where
#0 0x000000000008b0d6 in Tcl_GetVar@plt ()
#1 0x00007f53bf1ce3ff in SWIG_Tcl_GetModule (interp=0x1786670)

at simulavr_wrap.cxx:1193

#2 SWIG_InitializeModule (clientdata=0x1786670) at simulavr_wrap.cxx:23212
#3 Simulavr_Init (interp=0x1786670) at simulavr_wrap.cxx:23465
#4 0x000000307f2a1249 in ?? () from /lib64/libtcl8.5.so
#5 0x000000307f234244 in ?? () from /lib64/libtcl8.5.so
#6 0x000000307f23525e in ?? () from /lib64/libtcl8.5.so
#7 0x000000307f235796 in Tcl_EvalEx () from /lib64/libtcl8.5.so
#8 0x000000307f29be72 in Tcl_FSEvalFileEx () from /lib64/libtcl8.5.so
#9 0x000000307f2a25a3 in Tcl_Main () from /lib64/libtcl8.5.so
#10 0x00000000004007d0 in ?? ()
#11 0x0000000000000000 in ?? ()

If I use the original simulavr git from clone git://git.savannah.nongnu.org/simulavr.git
the tcl example work as expected.

this is my configure:
./configure --enable-python --enable-tcl --enable-verilog --enable-dependency-tracking --with-bfd=/home/pat1/compilazioni/binutils-2.24/bfd/ --with-libiberty=/home/pat1/compilazioni/binutils-2.24/libiberty CXXFLAGS=-g CFLAGS=-g --no-create --no-recursion

and this the configuration for binutils 2.24:
./configure --prefix=/usr --libdir=/usr/lib64 --mandir=/usr/share/man --infodir=/usr/share/info --target=avr --disable-werror --disable-nls CFLAGS=-fpic CXXFLAGS=-fpic

[miso-]

It doesn't work because of unresolvable _Z7ELFLoadPK9AvrDevice symbol that comes from src/simulavr_wrap.cxx generated by SWIG from src/avrdevice.h. Fix is here.
As for the segfault: It's caused by double call to dlopen() with the same file as argument in TclpDlopen. First call fails, as it should, with "undefined symbol: _Z7ELFLoadPK9AvrDevice" errstring, then in second dlopen call, _dl_map_object finds mapping left over by previous unsuccessful dlopen call. This is then returned by dlopen as handle. So program ends up with non-zero handle and garbled GOT, this later leads to segfault.

This dlopen behaviour appears to be known, though undocumented "feature".

[Traumflug]

Thanks a lot for the contribution, miso-. Just picked all three of your additional commits (from both topic branches) onto the traumflug branch here, it appears to work fine (as it did for me before).

A bit off topic, running RepRap firmwares inside SimulAVR is a magnificent tool. Precision profiling takes some computing time, but it gives very repeatable and insightful results. For example here: Traumflug/Teacup_Firmware#61 (comment)

I hope very much we can find a similarly suited tool for these ARM Cortex-M0, Cortex-M3 and Cortex-M4 based devices.