[lldb-dev] Advice on debugging DSP and Harvard architectures

Matthew Gardiner mg11 at csr.com
Fri May 30 05:16:32 PDT 2014

Abid, Hafiz wrote:
>> So is the "add an offset" technique still the best way forward to solve this
>> problem? How about adding a new request (along with a query request to
>> interrogate the stub for support) for code reads - is this an option?
>> (If so, I'd be happy to do the work...)
> If you do this, then you will probably have to add the knowledge of whether you
> are reading a code memory or a data memory into the remote protocol layer and
> its callers. I think it would be more invasive change.
> One more issue that you may face is pointer residing in data memory
> but pointing to entities in code memory. The dwarf attribute DW_AT_address_class
> can be used to provide the required debug information. But you may need to
> add/improve the address space handling in lldb.
Yes, the change would be invasive. I was assuming that all regular 
accesses for memory reads/writes would be targeting the DATA bus, except 
for those reads required for the disassembler, which would be CODE 
reads. However, your mention of a function pointer breaks this 
assumption somewhat.
>> So, summarising, I'm wondering if anyone has any ideas/advice on the above
>> questions, that is, using lldb on harvard architectures and on non-standard-
>> byte-size architectures.
> Do you have a clang port for your dsp? I wonder if you would have issues with
> expression parsing without clang knowing the details of your dsp. I may be
> completely wrong though.
We don't have such a clang port as yet. There is some talk here of 
providing an LLVM backend for our dsp at some stage, though.


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