[llvm-dev] CodeView layering

[Zachary Turner via llvm-dev]

DebugInfoCodeView is nto strictly a consumer, it is also a producer.

On Wed, Mar 21, 2018 at 1:29 PM <paul.robinson at sony.com> wrote:

> Intuitively I'd think MC and DebugInfo should be independent.  MC is a
> producer, DebugInfo is a consumer.  What's common is the definition of the
> structures they operate on, which doesn't properly belong to either one.
>
> --paulr
>
>
>
> *From:* llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf Of *David
> Blaikie via llvm-dev
> *Sent:* Wednesday, March 21, 2018 11:52 AM
> *To:* Zachary Turner
> *Cc:* llvm-dev
> *Subject:* Re: [llvm-dev] CodeView layering
>
>
>
> Someone internally's been dabbling with turning on some of Google's build
> system's stricter header checking modes - and they caught these (you can
> check the internal code review 184305506 for the original where I'm pulling
> things out from).
>
> & yeah, fair question about the modules builds - I don't fully understand
> what they catch and don't catch. I suspect it's a matter of whether the
> headers themselves form a cycle - whereas the Google build system's a bit
> more structured - knowing about libraries and explicit dependencies between
> them.
>
> & I didn't look closely to see if, as I said, MC could depend on
> DebugInfoCodeView - probably weird/awkward/not what we want (I'm guessing?)
> but the modules buildbots don't have explicit dependencies, they just fail
> when they find a cycle. So they can implicitly support all sorts of weird
> dependencies we might not've expected/planned, so long as it's not an
> actual cycle (& only within the headers - so the modules system might be
> like "oh, sure, MC can depend on DebugInfoCodeView" but the library
> dependency might be the exact opposite (some MC .cpp file could call into
> DebugInfoCodeView & the modules build wouldn't fail - it knows nothing
> about .cpp modularity/grouping, just headers))
>
>
>
> On Wed, Mar 21, 2018 at 11:42 AM Zachary Turner <zturner at google.com>
> wrote:
>
> Yes, some of the headers and stuff that are just raw structure definitions
> and enums could probably be sunk into BinaryFormat..
>
>
>
> How'd you find this?  Curious why it hasn't been breaking in modules
> builds for a long time.
>
>
>
> 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?
>
> include/llvm/Object/COFF.h includes
> include/llvm/DebugInfo/CodeView/CVDebugRecord.h
>   Also seems like this could/should/needs to be sunk into BinaryFormat?
>
> 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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