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Re: [RFC/RFA] use of dwarf2 unwind informations
- To: Jim Blandy <jimb at zwingli dot cygnus dot com>
- Subject: Re: [RFC/RFA] use of dwarf2 unwind informations
- From: Daniel Berlin <dan at cgsoftware dot com>
- Date: Wed, 17 Oct 2001 08:19:35 -0400
- Cc: Jiri Smid <smid at suse dot cz>, gdb-patches at sources dot redhat dot com
- References: <s8vk7ylt15f.fsf@naga.suse.cz><npu1wy8cz4.fsf@zwingli.cygnus.com>
Jim Blandy <jimb@zwingli.cygnus.com> writes:
> 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?
Errr, gcc trunk will produce debug_frame info by default for dwarf2
now.
>
> - 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?
It depends.
Unless he changed the code i gave him a whole lot, which reading
through the reading portion, he didn't, it should support both.
>
> - 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!
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