On Fri, 26 Aug 2011 19:35 +0200, "Lluís" <xscr...@gmx.net> wrote: > Benjamin Ylvisaker writes: > > > I am working on a project for which I'd like to gather statistics > > about register usage. (For example, distributions of degree-of-use > > and dynamic lifetimes of register-values.) Is QEMU a good tool for > > doing this kind of work? Has anyone else done this? I looked at the > > tracing available in QEMU and it seems to be mostly for higher level > > things like memory accesses, function calls, basic block executions, > > etc. > > This is not currently possible. > > In fact, I've been developing (somewhat in the background) the kind of > features you're asking for, but it will still be at least a couple of > months before it's in a publishable state. > > Meanwhile, there are some tools you can use to accomplish this > (depending on your requirements), like valgrind or pintool.
By "not currently possible" do you mean the current tracing facilities don't support register/instruction granularity, or that there's something in the QEMU architecture itself that would require substantial changes to gather such information? I am willing to put in a fair bit of hacking effort. I only have a cursory understanding of the internals of QEMU, but shouldn't it be possible to hack the instruction translations to do some extra work? I had been under the impression that QEMU was more likely to do what I want than Valgrind or Pin. I thought those tools were a bit higher level and had no intention of giving instruction-granularity control of the guest program. I will take another look, though. Thanks, Ben
