[LLVMdev] Reimplementing Darwin's dsymutil as an lld helper

[Frédéric Riss]

> On Nov 7, 2014, at 10:07 AM, Shankar Easwaran <shankare at codeaurora.org> wrote:
> 
> Thanks for your reply, Fred.
> 
> It might work better, if its in a form of an API. So that the linker could call an API instead of running a tool ?

Yes, the long term goal would be to expose it as an API. The separate tool is just a first step. I can’t give you the exact shape of the API know, but basically the main entry point would be something like:

DwarfLinker::link(const DebugMap& map);

Where the DebugMap is a collection of object files containing debug info associated with symbol mappings. In the end the dsymutil utility should just be a thin command line wrapper around that.

> On 11/7/2014 11:53 AM, Frédéric Riss wrote:
>>> On Nov 7, 2014, at 9:20 AM, Shankar Easwaran <shankare at codeaurora.org> wrote:
>>> 
>>> Hi Fred,
>>> 
>>> Could this tool be extended to read DWARF information in the final image and then pack it differently for other architectures as well ?
>> I guess it could, depending on what you exactly mean by “pack it differently”. It could certainly strip some parts, or merge it with other file’s debug information (But I’m not sure why you’d do that on a fully linked binary).
> I meant pack it differently for de-duplication.

I see. Just in order to reduce the debug info size. I /think/ it should be possible to apply some of dsymutil’s optimizations to a linked dwarf binary. It’s outside of the scope of what I plan to do for the initial implementation, but it should be possible to reus of the code to implement that. I can definitely try to keep that usecase in mind when I write the code though.

Fred

> Shankar Easwaran
> 
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