[aeb] Re: GNU toolchain and AEB

[Momchil Velikov]

>>>>> "Fernando" == Fernando Nasser <fnasser@cygnus.com> writes:

Fernando> Momchil Velikov wrote:
>> 
>> >>>>> "Fernando" == Fernando Nasser <fnasser@cygnus.com> writes:
>> 
>> >> The following looks also strange to me:
>> >> 74      void TaskList::insert(Task * pTask)
>> >> -       75      {
>> >> -       76              Task * ppPrev = this->pTop;
>> >> 77
>> >> 78              //
>> >> 79              // Handle  the case of an empty list.
>> >> 80              //
>> >> -       81              if (ppPrev == NULL)
>> >> 82              {
>> >> 83                      ppPrev == pTask;
>> >> 84                      return;
>> >> 85              }
>> >>
>> >> This is how it looks in gdb. No instruction at "ppPrev == pTask; " and
>> >> "return;  ".
>> >>
>> 
Fernando> This is a very trivial method and it probably got optimized in some smart way.
Fernando> Use the MIXED mode to see what are the assembler instructions that were
Fernando> associated with the source lines.
>> 
>> Sorry if I completely missed the point, but what instructions
>> do you guys expect to be generated for `ppPrev == pTask;' ?
>> 

Fernando> That is a question for the GCC list.
Since this is a comparison with no side effects
(I presume operator== is not overriden), I'd expect every decent
compiler to generate no code.

Fernando> Here is how it works:

Fernando> 1) The compiler generates the code and also debugging information
Fernando>    (when you specify -g or similar option).
Fernando>    In this case the association between source line numbers and
Fernando>    instruction addresses.

Fernando> 2) All this extra info gets packed into the executable.

Fernando> 3) GDB reads WHATEVER THE COMPILER GENERATED.
Well, thanks, having implemented a debugger myself I
completely agree with you.  :-)


Regards,
-velco