[llvm-dev] CodeView layering

[Reid Kleckner via llvm-dev]

No, Object is supposed to be an abstraction over real object files and LLVM
bitcode object files.

Maybe we can break the CodeView -> Object dependency.

On Thu, Mar 29, 2018 at 4:23 PM Zachary Turner <zturner at google.com> wrote:

> It seems a little strange conceptually that object depends on
> BitcodeReader. Is it possible to break that dependency?
> On Thu, Mar 29, 2018 at 4:11 PM David Blaikie <dblaikie at gmail.com> wrote:
>
>> On Mon, Mar 26, 2018 at 4:52 PM David Blaikie <dblaikie at gmail.com> wrote:
>>
>>> On Thu, Mar 22, 2018 at 12:55 PM Reid Kleckner <rnk at google.com> wrote:
>>>
>>>> On Wed, Mar 21, 2018 at 11:31 AM David Blaikie <dblaikie at gmail.com>
>>>> wrote:
>>>>
>>>>> I'm looking at fixing some layering violations in LLVM & came across a
>>>>> few in the CodeView handling, specifically:
>>>>>
>>>>> lib/MC/MCCodeView includes several llvm/DebugInfo/CodeView headers
>>>>>   I guess MC could be made dependent on DebugInfoCodeView? But
>>>>> probably these things should be sunk into BinaryFormat as is the case for
>>>>> DWARF features used by MC?
>>>>>
>>>>
>>>> I'd be OK with that. We could very easily introduce true link
>>>> dependencies on that library in the near future.
>>>>
>>>
>>> OK - added the LLVMBuild.txt change in r328595
>>>
>>
>> Hmm, not perfect - this creates a bit of a circular dependency:
>>
>> llvm-tblgen
>> MC
>> DebugInfo/CodeView
>> Object
>> Bitcode/Reader
>> IR (including lib/IR/AttributesCompatFunc.inc)
>> llvm-tblgen (to generate AttributesCompatFunc.inc)
>>
>> This is just a specific path shown by the internal build system - no
>> doubt there are other tblgen files in LLVM IR, etc.
>>
>> So I guess still need to split up DebugInfo/CodeView (assuming the bits
>> needed by MC don't depend on Object)? Any suggestions? Sink it into
>> BinaryFormat or name a new library?
>>
>> (it's quite a few headers by the looks of it: CodeView.h, Line.h,
>> SymbolRecord.h, CodeViewTypes.def, CodeViewSymbols.def,
>> CodeViewRegisters.def, TypeIndex.h, CVRecord.h, CodeViewError.h,
>> RecordSerialization.h - maybe some of those aren't needed, if they're
>> excessive includes or the like (they tend to seep in all over the place))
>>
>>
>>>
>>>
>>>> include/llvm/Object/COFF.h includes
>>>>> include/llvm/DebugInfo/CodeView/CVDebugRecord.h
>>>>>   Also seems like this could/should/needs to be sunk into BinaryFormat?
>>>>>
>>>>
>>>> These things are really more PE/PDB related than CodeView. They are in
>>>> the wrong place. I'd ask Saleem to help find a new home. Object or
>>>> BinaryFormats seem OK to me.
>>>>
>>>
>>> Moved it to libObject (r328593) for now which is at least correct - if
>>> someone thinks it'd be more suited to BinaryFormat, I'm happy to move it or
>>> they can.
>>>
>>>
>>>>
>>>>
>>>>> I'm open to ideas & happy to do the work, or help in any way that
>>>>> might be useful.
>>>>>
>>>>> Thanks,
>>>>> - Dave
>>>>>
>>>>
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