[llvm-dev] [lldb-dev] Trying out lld to link windows binaries (using msvc as a compiler)

Leonardo Santagada via llvm-dev llvm-dev at lists.llvm.org
Fri Jan 26 11:38:29 PST 2018


it does.

I just had an epiphany: why not just write a .ghash file and have lld read
those if they exist for an .obj file?

Seem much simpler than trying to wire up a 20 year old file format. I will
try to do this, is something like this acceptable for LLD? The cool thing
is that I can generate .ghash for .lib or any obj lying around (maybe even
for pdb in the future).

On Fri, Jan 26, 2018 at 8:32 PM, Zachary Turner <zturner at google.com> wrote:

> In general, we should be able to accept any MSVC .obj file to LLD.  At the
> very least, we're not aware of any cases that don't work.
>
> Does your MSVC .obj file link fine before you add the .debug$H?
>
> On Fri, Jan 26, 2018 at 11:23 AM Leonardo Santagada <santagada at gmail.com>
> wrote:
>
>> Okay, apparently coff2yaml and yaml2coff are not in a great place as they
>> both don't deal well with the fact that you can have overlapping sections,
>> which seems to be what clang-cl produces (the .data section points to the
>> same place as a later section). Which is not a big big problem for me
>> particularly because msvc doesn't even generate .data sections in .obj.
>>
>> I'm trying to put support for .bss sections in both coff2yaml and
>> yaml2coff... but I still can link just fine with my transformations
>> clang-cl generated files... what does give me problems is msvc .obj files.
>> Have you tried to link one of these?
>>
>> On Fri, Jan 26, 2018 at 8:05 PM, Leonardo Santagada <santagada at gmail.com>
>> wrote:
>>
>>> yeah, apparently .bss has a flag of unitialized data that is not being
>>> respected on the layout of the coff files (it should skip those sections)
>>> but I dunno what to do with .data as it doesn't have a size.
>>>
>>> (resending as apparently my pastes generated a ton of hidden html data
>>> and this message hit the mailinglist limit of 100k)
>>> --
>>>
>>> Leonardo Santagada
>>>
>>
>>
>>
>> --
>>
>> Leonardo Santagada
>>
>


-- 

Leonardo Santagada
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