> > This example shows local in %eax, which is a caller-save (i.e., > > scratch) register. GCC is right to show that the value is unknown upon > > return from the call, because set() can clobber that register. > > Sorry, typo -- %eax is a *callee-save* register.
Argh! No, I was right the first time. %eax is a caller-save (scratch) register. Here was the typo: > Try changing your code so that you use the value of local after the > call to set() -- say, make it "local += 123" -- and see the > difference. My copy of GCC moves local to %ebx, which is a caller-save > register, and the location list shows it live in that register all the > way through the call and return. %ebx is a *callee-save* (preserved) register. I always have to think twice and I still get callee-save and caller-save backwards! That's why I prefer the terms "scratch" and "preserved". Sorry for the confusion. David correctly said it was a caller-save register in his original mail, and if I hadn't thought "callee-save" instead, I'd have been able to answer his question straight away. -cary _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
