On Tue, Feb 11, 2014 at 08:50:13AM -0300, Arnaldo Carvalho de Melo wrote: > Em Tue, Feb 11, 2014 at 12:14:21PM +0100, Peter Zijlstra escreveu: > > On Tue, Feb 11, 2014 at 12:08:56PM +0100, Stephane Eranian wrote: > > > Assuming you can decode and get the info about the base registers used, > > > you'd have to do this for each arch with load/store sampling capabilities. > > > this is painful compared to getting the portable info from dwarf directly. > > > But its useful now, as compared to whenever GCC gets around to > > implementing more dwarves and that GCC getting used widely enough to > > actually rely on it. > > > All you need for the decode is a disassembler, and every arch should > > already have multiple of those. Should be easy to reuse one, right? > > Yeah, I never got around to actually try to implement this, but my > feeling was that all the bits and pieces were there already: > > 1) the precise IP for the instruction, that disassembled would tell > which registers were being operated on, or memory that we would "reverse > map" to a register > > 2) DWARF expression locations that allows us to go from registers to a > variable/parameter and thus to a type > > 3) PERF_SAMPLE_REGS_USER (from a quick look, why do we have "USER" in > it? Jiri?)
well, it was meant for store user registers only to assists user DWARF unwind we can add PERF_SAMPLE_REGS_KERNEL > > 4) libunwind have register maps for various arches, so probably > something there could be reused here as well (Jiri?) not sure what you mean by 'something' here.. but yep, libunwind does have register maps for various arches jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
