[lldb-dev] Questions for module/symbol load/unload events

[Jeffrey Tan via lldb-dev]

Btw: I did not find an API to retrieve the load address of the SBModule?
This seems to be weird to me, did I miss anything?


On Mon, Feb 29, 2016 at 1:34 PM, Jeffrey Tan <jeffrey.fudan at gmail.com>
wrote:

> I see why I did not find them in the first place. These two APIs are not
> listed in the official doc:
> http://lldb.llvm.org/python_reference/index.html
>
> Someone might want to add it.
>
> Thanks
> Jeffrey
>
> On Mon, Feb 29, 2016 at 11:59 AM, Jeffrey Tan <jeffrey.fudan at gmail.com>
> wrote:
>
>> This is very useful, thanks for the info!
>>
>> On Mon, Feb 29, 2016 at 10:36 AM, Jim Ingham <jingham at apple.com> wrote:
>>
>>>
>>> On Feb 27, 2016, at 8:34 PM, Jeffrey Tan via lldb-dev <
>>> lldb-dev at lists.llvm.org> wrote:
>>>
>>> Hi,
>>>
>>> I am trying to listen for module/symbol load/unload events and display
>>> them in output UI so that debugger users can have a basic clue what is
>>> debugger busy doing while launching a big executable linking many shared
>>> libraries.
>>>
>>> Questions:
>>> 1. I did not find an API to get current load/unload module during module
>>> events. I was expecting some static API like lldb.SBModule(or
>>> SBTarget).GetModuleFromEvent(SBEvent), but this does not exists. I tried to
>>> treat current PC's module as loading module in module load/unload events.
>>> But that does not work too(I think because process is not stopped in module
>>> load/unload events). Do I miss something here?
>>>
>>>
>>> From SBTarget.h:
>>>
>>>     static uint32_t
>>>     GetNumModulesFromEvent (const lldb::SBEvent &event);
>>>
>>>     static lldb::SBModule
>>>     GetModuleAtIndexFromEvent (const uint32_t idx, const lldb::SBEvent
>>> &event);
>>>
>>> Note, you can also cause the process to stop with modules are loaded
>>> with the setting:
>>>
>>> target.process.stop-on-sharedlibrary-events
>>>
>>> if that is more convenient for you.
>>>
>>>
>>> 2. Even though "image list" shows I have around 42 modules loaded in
>>> process, I only got two module load events. Why is that?
>>>
>>>
>>> On OS X the loader loads the closure of modules for whatever it is
>>> loading, and only stops and informs the debugger when this is all done.  So
>>> it is quite usual to see only a few load events even though many modules
>>> get loaded.
>>>
>>>
>>>
>>> 3. Even though I added lldb.SBTarget.eBroadcastBitSymbolsLoaded, there
>>> is no event of type eBroadcastBitSymbolsLoaded generated. Is it expected?
>>> Apparently I have the symbols next to the binary.
>>>
>>>
>>> That event gets sent when symbols are added to an already loaded
>>> module.  It is so a UI will know to refresh the backtrace, local variables,
>>> source view, etc when code goes from having no symbols to having some
>>> symbols.  Those actions are not needed if the library & its symbols get
>>> loaded simultaneously, so it isn’t sent in that case.
>>>
>>> Jim
>>>
>>>
>>>
>>> This is tested on mac OSX lldb.
>>>
>>> Jeffrey
>>> _______________________________________________
>>> lldb-dev mailing list
>>> lldb-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
>>>
>>>
>>>
>>
>
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