[llvm-dev] [RFC] Queries for LLVM version

[Timothy Arceri via llvm-dev]

On Wed, 2017-02-08 at 00:12 +0100, Nemanja Ivanovic wrote:
> I am certainly willing to write up a patch to do this. I was hoping
> to get a few more responses/buy-in from the community.
> And honestly, I'd be interested to know if this can be back-ported to
> at least 4.0 if it gets accepted.

My *possible* use case is for identifying the version of llvm used to
compile shaders for AMD gpus. This information would be used with an
on-disk cache of compiled shaders allowing old cache items to be
ignored if llvm is upgraded.

One downside of this is there is no way to know if distros backport
fixes to llvm. If the version is not bumped then the a buggy cached
shader would continue to be used even after the distro makes the fix.


> 
> Now that I see that there's more interest in this than just my own,
> I'll put up a patch on Phabricator.

Cool, thanks!

> 
> On Wed, Feb 8, 2017 at 12:04 AM, Timothy Arceri via llvm-dev <llvm-de
> v at lists.llvm.org> wrote:
> > On 01/26/2017 12:45 AM, Nemanja Ivanovic via llvm-dev wrote:
> > > This has actually come up in the context of a JIT, but I think
> > that 
> > > having the functionality in general could be useful.
> > >
> > > Currently, there does not appear to be an API in LLVM to query
> > for 
> > > LLVM version information. In the particular context where this
> > came 
> > > up, LLVM is used as a shared library and various functionality
> > (and 
> > > bug fixes) used by the JIT is available in various LLVM versions.
> > So 
> > > it would be quite convenient to be able to dynamically determine
> > the 
> > > version that happens to be loaded.
> > >
> > > Honestly, I am not completely clear on what the best place for 
> > > something like this would be, but it appears that the following
> > seems 
> > > like a natural choice:
> > >
> > > llvm::VersionPrinter in lib/Support/CommandLine.cpp already
> > queries 
> > > this data so it might make sense for it to expose the following
> > API's 
> > > (as part of VersionPrinter, accessed through the instance):
> > > llvm::cl::getVersionMajor()
> > > llvm::cl::getVersionMinor()
> > > llvm::cl::getVersionPatch()
> > 
> > Hi,
> > 
> > I'm also interested in querying this at runtime. Has there been any
> > patches submitted for this yet?
> > 
> > Thanks,
> > Tim
> > _______________________________________________
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> > llvm-dev at lists.llvm.org
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> > 
> 
>