(I'm reposting this because I'm not sure what happened to the one that I
sent to parrotbugs; forgive me if two eventually appear)
Folks,
There seems to be some problems with -O1 when instructions are optimised
at the end of functions. For instance, take
sub main
func ()
end
sub func
$I0 += 1
end
which translates to
main:
@pcc_sub_call_0:
set I0, 1
set I1, 0
set I2, 0
set I3, 0
set I4, 0
set S1, ""
set_p_pc P0, func
invokecc
null I0
null I3
returncc
func:
add I30, 1
null I0
null I3
returncc
When optimised with -O1 you instead get
main:
@pcc_sub_call_0:
set I0, 1
set I1, 0
set I2, 0
set I3, 0
set I4, 0
set S1, ""
set_p_pc P0, func
invokecc
null I0
null I3
returncc
func:
inc I30
where the tail of func is lost after the instruction has been
substituted (and as such core dumps for me as control goes past the end
of the bytecode).
In what is semi-related to this, if a deleted instruction (e.g. $I0+=0)
is at the end of a function, you get a core dump in imcc/optimiser.c in
this line (because ins is NULL):
ins = ins->prev ? ins->prev : unit->instructions;
If no ones picked this up in the next couple of days, I'll hopefully
have time to get my teeth into it...
Cheers,
Nick
