[lldb-dev] Trouble with 'target modules search-paths...'

[Greg Clayton]

On Mar 27, 2014, at 5:15 AM, Aidan Dodds <aidan at codeplay.com> wrote:

> Hi Greg,
> 
> Thanks for the reply.
> That was my impression also, that it was there to try to resolve missing images.
> 
> 
> I have started to unravel the problem that I am seeing, but my knowledge is still patchy with regards to some of the workings of Target.
> 
> When I attach to my process, the DynamicLoaders DidAttach() method fires.  This enumerates the target module and calls Target::SetSectionLoadAddress() for
> each section found.  Thus it seems the Target::m_section_load_history member is populated by the dynamic loader.
> 
> Next, I set the search path, which fires the Target::ImageSearchPathsChanged() callback.  Part of this process is to call Target::ClearModules(), which
> runs m_section_load_history.Clear();  Clearing all of the information on the loaded sections.
> 
> After this process, the dynamic loader never gets the chance to rebuild Target::m_section_load_history.
> Thus things like Target::ResolveLoadAddress() will fail.
> 
> 
> Do you have any suggestions for a clean way to fix this problem?

Set your search paths prior to running and creating your target.

> 
> It seems to me one way would be to add a new method to Target, which would resolve any currently unloaded modules, without unloading everything that is already loaded.
> This could then be called instead from Target::ImageSearchPathsChanged(), instead of unloading and reloading the executable to get the same effect.
> 
> Does that sound right?

Yes it does.

> 
> Thanks,
> Aidan
> 
> 
> On 26/03/2014 18:14, Greg Clayton wrote:
>> I believe it is assuming that by loading the module again, any shared libraries that weren't found could now be located. Lets say you loaded some file:
>> 
>> (lldb) file a.out
>> (lldb) image list
>> a.out
>> 
>> Only 1 file was found, even though a.out said it depended on /usr/lib/libfoo.so and /usr/lib/libbar.so...
>> 
>> Then you modify the search paths, and then
>> 
>> (lldb) file a.out
>> (lldb) target modules search-paths add . d:/foo
>> (lldb) image list
>> a.out
>> d:/libfoo.so
>> d:/libbar.so
>> 
>> This is probably what the intent was. So try doing a "image list" before and after and see what differs.
>> 
>> On Mar 25, 2014, at 9:44 AM, Aidan Dodds <aidan at codeplay.com> wrote:
>> 
>>> Hi All,
>>> 
>>> I have been experiencing some problems when using the following command:
>>> 
>>> (lldb) target modules search-paths add . d:/foo
>>> 
>>> My intent is to set the folder for LLDB to locate any shared object files that the gdbremote target may load via dlopen().
>>> After issuing the above command all of the loaded sections in the target executable seems to be missing, and I am unable to
>>> find a LoadAddresses for any symbols etc.
>>> 
>>> I have come across the code below, from "source/Target/Target.cpp at line:1748"
>>> 
>>> void
>>> Target::ImageSearchPathsChanged
>>> (
>>>    const PathMappingList &path_list,
>>>    void *baton
>>> )
>>> {
>>>    Target *target = (Target *)baton;
>>>    ModuleSP exe_module_sp (target->GetExecutableModule());
>>>    if (exe_module_sp)
>>>        target->SetExecutableModule (exe_module_sp, true);
>>> }
>>> 
>>> When I disable this code then everything works as expected for me.
>>> 
>>> I am wondering what the intent of this code is?
>>> or does anyone have any ideas why I would be seeing such problems?
>>> 
>>> Thanks,
>>> Aidan
>>> 
>>> -- 
>>> Aidan Dodds
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