Re: [RFC/RFA] use of dwarf2 unwind informations

[Jim Blandy <jimb@zwingli.cygnus.com>]

Jiri Smid <smid@suse.cz> writes:
>   This is code which allows gdb to use dwarf2 frame informations for
> stack unwinding.

It looks good; could you commit this?

I have some initial questions, though:

- How can I get GCC to produce .debug_frame sections to test this?
  Do you have a patch for GCC I could use, or is there some flag we
  can use to simply have GCC divert its .eh_frame contents to a
  .debug_frame section?

- It's my understanding that the .eh_frame format used by GCC and the
  .debug_frame format described in the Dwarf2 standard are actually
  slightly different.  Which one does your patch support?

- Is context_cpy correct?  It seems to me that it copies the immediate
  contents of the `struct context', but then only copies the first
  element of the `reg' array.

- The `read_pointer' function assumes `sizeof (CORE_ADDR)' in GDB
  gives the size of pointers appearing the Dwarf 2 information.  This
  confuses a host type (CORE_ADDR) with what I think is supposed to be
  a target-sized address.  CORE_ADDR is simply the largest unsigned
  integer type GDB can find.  I think it should use TARGET_ADDR_BIT /
  TARGET_CHAR_BIT, unless the Dwarf 2 info specifies the proper size
  somewhere, the way it does for .debug_info data.


... Anyway, I'll keep reading.  Thanks very much!