segfaults

[Steven Schveighoffer]

On Mon, 22 Feb 2010 21:14:08 -0500, Ellery Newcomer  
<ellery-newcomer at utulsa.edu> wrote:

> Is there any decent way to figure out where segfaults are coming from?
>
> e.g. 200k lines of bad code converted from java
>
> I tried gdb, and it didn't seem to work too well.
>
> Die: DW_TAG_type_unit (abbrev 3, offset 0x6d)
>    parent at offset: 0xb
>    has children: FALSE
>    attributes:
>      DW_AT_byte_size (DW_FORM_data1) constant: 8
> Dwarf Error: Missing children for type unit [in module  
> /home/ellery/dxl.exe]
> Missing separate debuginfos, use: debuginfo-install glibc-2.11.1-1.i686
>
>
> And I'm not proficient with gdb.
>
> dmd 1.056 / tango .99999 or whatever
>
> fedora linux

GDB is probably the best option.  Have you tried compiling with -gc?  I've  
had luck with that in the past.

Segfault gives you a signal (SIGSEGV), you could try handling the signal  
to print information about where the program is.

Other than that, you could try logging.  Tango has really good logging  
facilities.  Try putting logging messages in functions that get called at  
various stages in the program.  You can continue to narrow down where the  
failure is by instrumenting even further.  Once you determine the function  
it's in, then I usually do something like this after every line:

Stdout.formatln("here {}", __LINE__);

Of course, Tango's Stdout is thread unsafe, I can't remember the thread  
safe version, something like Trace (if you are using threads).

You should get a line number just before the failed call.

-Steve