decoding of multi-byte nops in dtrace
Andriy Gapon
avg at FreeBSD.org
Tue Jun 12 05:37:45 UTC 2012
on 11/06/2012 06:49 perryh at pluto.rain.com said the following:
> Sounds as if DTrace could use an improvement to recognize and handle
> the tail call optimization, maybe something along the lines of:
>
> If a function has no otherwise-determined return probe
> and it contains a jump to the entry point of another function
> then it inherits that other function's return probe.
>
> I'd expect that to handle cases like
>
> int bar(...)
> {
> ...
> return baz;
> }
>
> int foo(...)
> {
> ...
> return bar(...);
> }
>
> (although probably not cases where the return in foo calls a
> function pointer). And no, I am not volunteering to add it --
> ENOTIME :(
(Open)Solaris fdt code for sparc already handles this case (last instruction in
a function being a call), but not any other implementation.
Not sure if that is for technical reasons or if nobody just bothered.
--
Andriy Gapon
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