gdb under FC devel and undefined symbols

John Reiser jreiser at BitWagon.com
Fri Feb 17 18:36:21 UTC 2006


> flavor is a *int:
> 
> int i, *flavor, yum = 0;

Because flavor is a scalar, it is often somewhat easy for the compiler
to "eliminate" it, leaving no memory location where it resides.
In many cases a register is assigned.  If for an entire statement,
then the register could be tagged as the location of the variable,
but if for less than an entire statement then it gets cloudy as to
what is reasonable.

> x86 assembler is not a total stranger to me.

The one-minute into is:
  (gdb) x/4i $pc  # next instruction and following 3
  (gdb) x/12i $pc-0x18  # heuristic for plausible previous instructions
  (gdb) p $eax   # register %eax
  (gdb) p $ebp   # stack frame pointer, if used as such
  (gdb) stepi   # single-step one instruction

-- 




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