Importing debug information into dbx

I’m sure I wrote this up somewhere before,but now I can’t find it. Just in case you guys (my two faithful readers) haven’t seen this trick yet. If you are stuck with a core file that doesn’t have debug information,you can “import”debugging information using the “loadobject -load”command. It’s especially useful for C++ to help get rid of the mangled names that show up in stack traces.

% #########################% more t.c#include "t.h"struct foo foofoo;intmain(){ foofoo.a = 1; foofoo.b = 2; * (int *) 0 = 0}% #########################% more t.hstruct foo{int a;int b};% #########################% cc -o t t.c # no debug info% #########################% ./tSegmentation Fault (core dumped)% #########################% dbx t coreReading tcore file header read successfullyReading ld.so.1Reading libc.so.1Reading libdl.so.1Reading libc_psr.so.1program terminated by signal SEGV (no mapping at the fault address)0x00010bb4:main+0x001c: clr [0](dbx) whatis foofoodbx:warning:unknown language,'c' assumed(int{assumed}) foofoo;(dbx) print foofoofoofoo = 0x1(dbx) whatis -t foodbx:"foo" is not defined in the scope `t`main`dbx:see `help scope' for details(dbx) quit% #% # You really want to see the contents of the 'foofoo'% # structure,but the binary doesn't have debug info!% # So create a dummy .so file with debug info,and load% # that into dbx manually.% # % #########################% more dummy.c#include "t.h"% #########################% cc -G -g -o dummy.so dummy.c% #########################% dbx t coreReading tcore file header read successfullyReading ld.so.1Reading libc.so.1Reading libdl.so.1Reading libc_psr.so.1program terminated by signal SEGV (no mapping at the fault address)0x00010bb4:main+0x001c: clr [0](dbx) loadobject -load dummy.soReading dummy.soLoaded loadobject:/set/dbx/somewhere/misc/coretest/dummy.so(dbx) modules | grep dummyNot Read dummy.o(dbx) module dummy.oRead dummy.o(dbx) whatis -t foostruct foo{ int a; int b};(dbx) print *(struct foo*)&foofoodbx:warning:unknown language,'c' assumed*((struct foo *) &foofoo) ={ a = 0x1  b = 0x2}