[lldb-dev] [Bug 16526] New: New API to scan executable for architectures before creating a target

Greg Clayton gclayton at apple.com
Mon Jul 8 15:29:09 PDT 2013

This should work for you:

% svn commit
Sending        include/lldb/API/SBDefines.h
Sending        include/lldb/API/SBFileSpec.h
Sending        include/lldb/API/SBModule.h
Adding         include/lldb/API/SBModuleSpec.h
Sending        include/lldb/API/SBStream.h
Sending        include/lldb/API/SBTarget.h
Sending        include/lldb/Core/ModuleSpec.h
Sending        include/lldb/Core/UUID.h
Sending        lldb.xcodeproj/project.pbxproj
Sending        scripts/Python/build-swig-Python.sh
Sending        scripts/Python/interface/SBModule.i
Adding         scripts/Python/interface/SBModuleSpec.i
Sending        scripts/Python/interface/SBTarget.i
Sending        scripts/Python/python-extensions.swig
Sending        scripts/lldb.swig
Sending        source/API/SBFileSpec.cpp
Sending        source/API/SBModule.cpp
Adding         source/API/SBModuleSpec.cpp
Sending        source/API/SBTarget.cpp
Sending        source/Core/UUID.cpp
Transmitting file data ....................
Committed revision 185877.

I have exposed SBModuleSpec and SBModuleSpecList.

You will want to use the static function:

SBModuleSpecList specs = SBModuleSpecList::GetModuleSpecifications("/usr/lib/dyld");

This will give you a list back and you can then get the size and enumerate:

const size_t count = specs.GetSize();
for (size_t i=0; i<count; ++i)
    ModuleSpec module_spec = specs.GetSpecAtIndex(i);
    const char *triple = module_spec.GetTriple();

This properly exposes module specifications so we can enumerate items within a file, and I have also added ways to create a SBModule from a SBModuleSpec:

SBModule module = SBModule (module_spec);

Or you can add a module to a target by given it a module specification:

SBModule module = target.AddModule (module_spec);

This also prepares us for being able to enumerate all .o file in a .a file (though I need to complete the ObjectContainerBSDArchive::GetModuleSpecifications(...) function.

Let me know if this works well for you and if we can mark your bug as fixed.

Greg Clayton

On Jul 8, 2013, at 11:38 AM, Sebastien Metrot <meeloo at gmail.com> wrote:

> Hi Greg,
> I understand your point. My use-case was not to enable parsing the module list but rather to be able to detect which archs are available in order to display a GUI control that let's the user choose which archs it wants to run on (and detect archs that we don't support right away such as ARM binaries on x86_64). That's why I tried to get the available archs for the executable module only.
> What is the best way to reconcile both approaches?
> S.
> On Jul 8, 2013, at 19:48 , Greg Clayton <gclayton at apple.com> wrote:
>> Your change currently allows architectures to be enumerated, but not .o files in a .a file. If you look closely at what the internal code is doing when it enumerates the module specifications, it can get a list of all architectures _and_ all .o files. If we expose this publicly, I would rather see a new SBModuleSpec and SBModuleSpecList class be created, and then we should be able to add a static function to SBModule that returns a SBModuleSpecList:
>> static SBModuleSpecList
>> SBModule::GetModuleSpecifications (const char *path);
>> This way we could take a universal .a file and get back a bunch of SBModuleSpec objects that represent the arch/objects in the .a file. Then we would need to have a function on SBTarget to add a module to a target using a SBModuleSpec.
>> Greg
>> On Jul 5, 2013, at 12:31 PM, meeloo at gmail.com wrote:
>>> Hi,
>>> Is there something I should do to have this patch proposal reviewed?
>>> Thanks,
>>> S.
>>> On Jul 2, 2013, at 19:47 , bugzilla-daemon at llvm.org wrote:
>>>> Bug ID	16526
>>>> Summary	New API to scan executable for architectures before creating a target           
>>>> Product	lldb
>>>> Version	unspecified
>>>> Hardware	All
>>>> OS	All
>>>> Status	NEW
>>>> Severity	enhancement
>>>> Priority	P
>>>> Component	All Bugs
>>>> Assignee	lldb-dev at cs.uiuc.edu
>>>> Reporter	meeloo at meeloo.net
>>>> Classification	Unclassified
>>>> Created attachment 10807 [details]
>>>> Diff to add lldb::SBDebugger::GetAvailableArchsFromFile
>>>> As I haven't found a way to scan available architectures from executables I'd
>>>> like to add that to the API. For now the only way to do somehow do that is to
>>>> loop over all known archs and try to create the SBTarget. Depending on its
>>>> success we mark the arch as valid or not. As you can guess this is very slow
>>>> and can be made mauch better as lldb already has all the code needed to get
>>>> this information without loading the full target. 
>>>> The public API for this could be added to SBDebugger:
>>>> static lldb::SBStringList lldb::SBDebugger::GetAvailableArchsFromFile(const
>>>> char* filename);
>>>> I have attached a patch implementing this feature.
>>>> Cheers,
>>>> S.
>>>> You are receiving this mail because:
>>>> 	• You are the assignee for the bug.
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