On 02/16/2015 10:43 AM, Volker Simonis wrote: > Now if we replicate this SA code one more time in a Python library for > GDB, you'll probably agree that it can't work more reliably than the > original SA code. This may be good enough for some use cases, but it > won't be perfect. I'm not a gdb/DWARF expert but I think what we > really need is to generate debug information for all the generated > code. We need to know for every single PC of generated code the > corresponding frame information and how to get to the previous frame.
It would be nice. We don't actually need it, given that we've done without for years, and generating e.g. full DWARF unwinder data for every instruction is something that even GCC doesn't always attempt to do. (And, of course, there's a lot of hand-written assembly code in HotSpot. Annotating this is a significant effort.) > I know it's possible and I know that gdb has callbacks to consume this > debug information which is generated at runtime (see [1]) although > I've never programmed it myself. LLVM seems to use this technique and > has some documentation available ([2,3]). I suppose this is the > direction Erik wanted to go and I think that would be the right way. It would be, long term. I've been discussing this with Red Hat's GDB group and I'm hoping to come up with a proposal and hopefully some working code. Andrew.
