[Lldb-commits] [PATCH] Handle ARM ELF symbols properly.

Todd Fiala tfiala at google.com
Mon Sep 15 10:05:18 PDT 2014


Hey Stephane,

On patch 2 - could you add some comments around these bits? It’s a little
unclear what’s happening there and I want to make sure we don’t break it at
some point later.

+ symbol_value_offset = -1;
- uint64_t symbol_value = symbol.st_value; + uint64_t symbol_value =
symbol.st_value | symbol_value_offset;

Other than that, it looks fine.  I'll wait on that for the patch submission
of part 2.

Also - not needed for the patch itself, but would be great as a follow up
would be adding a unit test to verify we’re correctly marking the thumb
code symbols. That’d be great if you could add a unit test for it.

Thanks!
-Todd

On Mon, Sep 15, 2014 at 9:38 AM, Todd Fiala <tfiala at google.com> wrote:

Part 1 committed here:
> ```
> svn commit
> Sending        source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
> Transmitting file data .
> Committed revision 217782.
> ```
>
> Stephane - it would be great if you could add a unit test to verify those
> symbols are getting stripped.  Let me know if you need help figuring out
> how the unit tests work.
>
> Looking at Part 2 now.
>
> -Todd
>
> On Wed, Sep 10, 2014 at 12:55 PM, Stephane Sezer <sas at fb.com> wrote:
>
>>  Re-sending these, as the first email didn’t reach the mailing list for
>> some reason.
>>
>>
>>
>> On Sep 9, 2014, at 5:27 PM, Stephane Sezer <sas at fb.com> wrote:
>>
>> > Two patches here:
>> >
>> > [PATCH 1/2] Skip $t* and $a* symbols in ObjectFileELF.
>> >
>> > ELF objects contain marker symbols to differentiate between ARM and
>> > THUMB functions. Instead of storing them internally and having garbage
>> > show up when symbols are searched for by the user, we can just skip them
>> > and not store them at all, as we never actually need them.
>> >
>> > [PATCH 2/2] Store the thumbness of a function in symbol flags.
>> >
>> > This allows us to fixup the address of the symbol as soon as we parse it
>> > so that lldb is not confused thinking there are two different symbols in
>> > the binary (one with the thumb bit, one without). Also, differentiating
>> > between THUMB and ARM symbols allows the debugger to place the right
>> > type of breakpoint.
>> >
>> >
>> >
>> <0001-Skip-t-and-a-symbols-in-ObjectFileELF.patch><0002-Store-the-thumbness-of-a-function-in-symbol-flags.patch>
>>
>>
>
>
> --
> Todd Fiala | Software Engineer | tfiala at google.com | 650-943-3180
>
​
-- 
Todd Fiala | Software Engineer | tfiala at google.com | 650-943-3180
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