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digitalmars.D.learn - linux linenumbers in stacktraces and druntime/phobos debug builds..

reply simendsjo <simendsjo gmail.com> writes:
I get an segfault in druntime, but have no idea where to start looking.
_D4core7runtime18runModuleUnitTestsUZb19unittestSegvHandlerUiPS4core3sys5posix6signal9siginfo_tPvZv+0x3c

I cannot seem to find a way to enable line numbers in traces (adding -g 
adds line numbers in win, but not linux), and I cannot find any debug 
build of libphobos2.a - is it included? what is it called?

PS: using dmd 2.057 on kubuntu x64 using the deb package from 
digitalmars.com
Feb 06 2012
next sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
On Monday, February 06, 2012 21:36:38 simendsjo wrote:

 I get an segfault in druntime, but have no idea where to start looking.
 _D4core7runtime18runModuleUnitTestsUZb19unittestSegvHandlerUiPS4core3sys5pos
 ix6signal9siginfo_tPvZv+0x3c
 
 I cannot seem to find a way to enable line numbers in traces (adding -g
 adds line numbers in win, but not linux), and I cannot find any debug
 build of libphobos2.a - is it included? what is it called?
 
 PS: using dmd 2.057 on kubuntu x64 using the deb package from
 digitalmars.com


Posix' backtrace facilities do not provide a way to get the file names or line 
numbers - just the addresses and symbol names (though the fact that module 
names and file names are normally the same makes it so that the file name is 
essentially in the symbol name in D). Now, according to this answer on 
stackoverflow

http://stackoverflow.com/questions/3151779/how-its-better-to-invoke-gdb-from-


it looks like it's possible to use addr2line to do the job under at least some 
circumstances. So, it may be possible to add it to druntime, but there's no 
way for you to just enable it.

Now, the stack traces _do_ give you the addresses, so you could use addr2line 
yourself to get the file and line numbers for at least some of the stack trace 
(some lines will probably yield ??:0). You _will_ have to compile with -g for 
that to work though (otherwise _all_ lines will yield ??:0).

- Jonathan M Davis
Feb 06 2012
prev sibling next sibling parent "Jesse Phillips" <jessekphillips+D gmail.com> writes:
On Monday, 6 February 2012 at 20:36:39 UTC, simendsjo wrote:

 I get an segfault in druntime, but have no idea where to start 
 looking.
 _D4core7runtime18runModuleUnitTestsUZb19unittestSegvHandlerUiPS4core3sys5posix6signal9siginfo_tPvZv+0x3c

 I cannot seem to find a way to enable line numbers in traces 
 (adding -g adds line numbers in win, but not linux), and I 
 cannot find any debug build of libphobos2.a - is it included? 
 what is it called?

 PS: using dmd 2.057 on kubuntu x64 using the deb package from 
 digitalmars.com


If you have a segmentation fault then you will need to compile 
with -g, turn on core dumps and use gdb.

$ ulimit -c unlimited
$ ./test
$ gdb ./test core

You will be provided with file and line number, well the file may 
just be a module name don't remember.

Also based on that mangled string it looks like you are running 
the Druntime unittests. I've never used the above to get at 
Unittest segfaults...
Feb 06 2012
prev sibling parent reply Vijay Nayar <vnayar wgen.net> writes:
I actually ran into this myself while working on a pet game project, and 
here's what I do.

First, let's start with a simple program that segfaults due to a null 
pointer.

// File seg.d
class Dummy {
     int a;
}

void main() {
     Dummy d;
     d.a = 3;
}

You compile and run the program with expected results.

  $ dmd seg.d
  $ ./seg
  Segmentation fault

If you have an older version of gdb, you should compile your program to 
include C compatible symbols.

  $ dmd -gc seg.d

Now run your program through gdb.
  $ gdb seg
  (gdb) run
  Starting program: /home/vnayar/projects/Demo/seg
  [Thread debugging using libthread_db enabled]

  Program received signal SIGSEGV, Segmentation fault.
  _Dmain () at seg.d:7
  7           d.a = 3;

And now you're good to go.

  - Vijay

On Mon, 6 Feb 2012, simendsjo wrote:


 I get an segfault in druntime, but have no idea where to start looking.
 _D4core7runtime18runModuleUnitTestsUZb19unittestSegvHandlerUiPS4core3sys5posix6signal9siginfo_tPvZv+0x3c

 I cannot seem to find a way to enable line numbers in traces (adding -g adds 
 line numbers in win, but not linux), and I cannot find any debug build of 
 libphobos2.a - is it included? what is it called?

 PS: using dmd 2.057 on kubuntu x64 using the deb package from digitalmars.com
Feb 08 2012
parent bearophile <bearophileHUGS lycos.com> writes:
Vijay Nayar:


 First, let's start with a simple program that segfaults due to a null 
 pointer.
 
 // File seg.d
 class Dummy {
      int a;
 }
 
 void main() {
      Dummy d;
      d.a = 3;
 }
 
 You compile and run the program with expected results.
 
   $ dmd seg.d
   $ ./seg
   Segmentation fault


Also try to compile it with -O  :-)

Bye,
bearophile
Feb 08 2012