[PATCH] D42762: Rewrite the VS Integration Scripts

[Zachary Turner via llvm-commits]

Also, since this is a build system issue and not a compiler issue, it seems
intuitive to me to deal with it at the build system level
On Fri, Feb 2, 2018 at 8:42 AM Zachary Turner <zturner at google.com> wrote:

> It’s a compiler generated pdb, /Zi means “all compiler processes should
> write to the same pdb”, whereas /Z7 means “put the debug info in the object
> files instead”. If the user does a clean build the file will get deleted
> and there won’t even be anything to touch. The file name comes from another
> flag (/Fo or /Fd, can’t remember) which msbuild defaults to vc$(ToolsetName)
> On Fri, Feb 2, 2018 at 8:36 AM Hans Wennborg <hans at chromium.org> wrote:
>
>> Yes, but I'd like to understand exactly why. Where does the name
>> vc140.pdb come from? What is supposed to go into this file? Maybe
>> clang-cl should touch it when invoked with /Zi?
>>
>> On Fri, Feb 2, 2018 at 5:32 PM, Zachary Turner <zturner at google.com>
>> wrote:
>> > Symptom: when /Zi is selected, VS always rebuilds all source files,
>> even if
>> > just 1 (possibly even none) have changed.
>> >
>> > Fix: Change /Zi to /Z7 in the UI
>> >
>> > More details here: https://bugs.llvm.org/show_bug.cgi?id=36140
>> >
>> > On Fri, Feb 2, 2018 at 8:12 AM Hans Wennborg <hans at chromium.org> wrote:
>> >>
>> >> On Fri, Feb 2, 2018 at 4:40 PM, Zachary Turner <zturner at google.com>
>> wrote:
>> >> >
>> >> > On Fri, Feb 2, 2018 at 6:23 AM Hans Wennborg <hans at chromium.org>
>> wrote:
>> >> >>
>> >> >> (Your reply didn't go to Phabricator, so re-adding folks subscribed
>> >> >> there.)
>> >> >>
>> >> >> On Thu, Feb 1, 2018 at 9:08 PM, Zachary Turner via llvm-commits
>> >> >> <llvm-commits at lists.llvm.org> wrote:
>> >> >> > I'm kind of imagining this world where we have one VS Integration
>> >> >> > that
>> >> >> > works
>> >> >> > no matter what version of LLVM you have.  The nice thing about
>> this
>> >> >> > is
>> >> >> > that
>> >> >> > it allows it to work with hermetic toolchains, older versions of
>> LLVM
>> >> >> > that
>> >> >> > may already be installed on a user's machine, local dev builds of
>> >> >> > LLVM,
>> >> >> > etc.
>> >> >>
>> >> >> I'm on board with this. It seems useful especially for the case
>> where
>> >> >> the developer may have multiple LLVM toolchains installed and want
>> to
>> >> >> point at a specific one. It would be nice if we could still trigger
>> >> >> the installation of the toolset when installing the LLVM toolchain
>> >> >> though.
>> >> >>
>> >> >> But for the integration to work regardless of LLVM version, I don't
>> >> >> think the integration can bake in assumptions about what flags
>> >> >> clang-cl supports and re-map them etc. The set of flags supported by
>> >> >> clang-cl and how they're handled changes frequently.
>> >> >>
>> >> >> I like the idea of a VS integration that's LLVM-version independent
>> --
>> >> >> the current one is almost that except for the baked in version
>> number
>> >> >> -- but for it to work, I think it has to be really simple, basically
>> >> >> just pointing MSVC at clang-cl.exe and nothing more.
>> >> >
>> >> > I’ve already mentioned at least one case whereas this is impossible
>> (/Zi
>> >> > vs
>> >> > /Z7), and given that there are thousands of lines of msbuild logic
>> that
>> >> > are
>> >> > running and processing these options before they make it to clang-cl,
>> >> > I’m
>> >> > certain there are more that we don’t yet know about.
>> >>
>> >> I'd like to understand the /Zi vs /Z7 thing better. Can you ELI5 the
>> >> problem?
>> >>
>> >>
>> >> >
>> >> > Simple is nice, I don’t disagree with that, but not at the expense of
>> >> > user
>> >> > experience.  i still don’t think there’s any maintenance issues here
>> >> > though.
>> >> > I think the current version here could probably sit for 5+ years and
>> >> > never
>> >> > need to be touched, continuing to work both with future VS versions
>> and
>> >> > future clang-cl versions unmodified.
>> >> >
>> >> >
>> >> >>
>> >> >>
>> >> >> > The only maintenance burden I can think of is one where we remove
>> or
>> >> >> > add
>> >> >> > flags in clang-cl, which doesn't happen very often, if ever.
>> >> >>
>> >> >> It puzzles me that you think we rarely or ever change the flags
>> >> >> clang-cl supports or how they're handled. In my experience, the
>> flags
>> >> >> change every release.
>> >> >>
>> >> >> >  Any flag that
>> >> >> > is added to MSVC doesn't require any action from us.
>> >> >>
>> >> >> Depends on the flag, no?
>> >> >
>> >> > Not really.  Any flag that msvc adds, assuming we don’t update this
>> >> > file,
>> >> > gets passed through to clang-cl which is what you’re proposing i do
>> with
>> >> > all
>> >> > options anyway.
>> >> >
>> >> >
>> >> >>
>> >> >>
>> >> >> > I plan to expose a UI for optimizations and warning, so I could
>> see a
>> >> >> > maintenace burden when we add new -W or -f flags that are not
>> exposed
>> >> >> > to
>> >> >> > the
>> >> >> > UI.  But those can still be specified via additional compiler
>> flags.
>> >> >> > And
>> >> >> > the maintenance burden is actually less than coupling it to the
>> >> >> > installed
>> >> >> > toolchain because we can do it at our leisure, rather than being
>> >> >> > pressed
>> >> >> > to
>> >> >> > get it done by a release.
>> >> >>
>> >> >> But you're saying that the toolset should be independent of the LLVM
>> >> >> version? If we add a -Wfoobar flag in Clang x.y.z and want to expose
>> >> >> that in your UI, that UI then needs to be conditional on what
>> version
>> >> >> of Clang it's targeting. Same thing if we remove -Wquux in another
>> >> >> Clang version. This sounds like a maintenance nightmare to me.
>> >> >
>> >> > If we do nothing, any added -W options are still available via
>> >> > Additional
>> >> > Compiler Flags.   So as with all the other custom logic in the
>> msbuild
>> >> > files, we’re still not obligated to maintain that, and it will still
>> >> > continue to work fine
>> >> >
>> >> > For options that we remove, sure, we should update the file.  One
>> way to
>> >> > handle this would be to add a new version of clang-cl.xml every
>> release,
>> >> > and
>> >> > conditionally include the proper xml file.  How frequently do we
>> remove
>> >> > warnings though?  Doing so would cause people’s builds to break
>> because
>> >> > they’d be passing unrecognized options, so I suspect it’s almost
>> never.
>> >> >
>> >> > Of all the things though, this is the one that I think it’s most
>> >> > important
>> >> > to accept the maintenance burden of.  This is the difference between
>> “we
>> >> > put
>> >> > the minimum amount of work possible into getting this working so we
>> >> > could do
>> >> > other things” and “we care about this, we made it as easy as
>> possible to
>> >> > use, we designed it with VS users in mind”.  As someone who used VS
>> >> > through
>> >> > the UI exclusively for over 15 years, there’s going to be a huge
>> >> > difference
>> >> > between providing this feature and not providing it.
>> >> >
>> >> > I *still* don’t see the maintenance burden as being high though.  We
>> can
>> >> > release a new clang-cl.xml like every 2-3 years and it would take
>> all of
>> >> > 30
>> >> > minutes to put it together and get it on the marketplace.
>> >> >
>> >> >
>> >> >
>> >> >>
>> >> >>
>> >> >>
>> >> >> > One thing I could maybe do to lower the maintenance burden a
>> little
>> >> >> > is
>> >> >> > to
>> >> >> > try to have some better logic for detecting the clang version.  We
>> >> >> > were
>> >> >> > already using the registry before anyway to find the installed
>> LLVM,
>> >> >> > maybe
>> >> >> > there's a way for me to just figure out the version without the
>> >> >> > additional
>> >> >> > registry value.  I'll have to look into that though.
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > On Thu, Feb 1, 2018 at 11:09 AM Zachary Turner <
>> zturner at google.com>
>> >> >> > wrote:
>> >> >> >>
>> >> >> >> On Thu, Feb 1, 2018 at 10:48 AM Hans Wennborg via Phabricator
>> >> >> >> <reviews at reviews.llvm.org> wrote:
>> >> >> >>>
>> >> >> >>> hans added inline comments.
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> ================
>> >> >> >>> Comment at: llvm/tools/msbuild/Clang.Cpp.Common.props:41
>> >> >> >>> +
>> >> >> >>> +    <!-- The registry key may not be set if it's an old
>> installer,
>> >> >> >>> try
>> >> >> >>> the newest version that exists -->
>> >> >> >>> +    <LLVMVersion Condition="'$(LLVMVersion)' == '' and
>> >> >> >>> Exists('$(LLVMInstallDir)\lib\clang\7.0.0')">7.0.0</LLVMVersion>
>> >> >> >>> ----------------
>> >> >> >>> zturner wrote:
>> >> >> >>> > hans wrote:
>> >> >> >>> > > As I mentioned before, separating the toolset config from
>> the
>> >> >> >>> > > actual
>> >> >> >>> > > toolchain installation makes me a little nervous.
>> >> >> >>> > >
>> >> >> >>> > > But if we're doing it, the version checks below should
>> probably
>> >> >> >>> > > include the .1 versions too, i.e. at least 5.0.1 and 6.0.1.
>> >> >> >>> > Unless we're going to release the full thing including the
>> >> >> >>> > compiler,
>> >> >> >>> > linker, etc through the marketplace I don't see an
>> alternative.
>> >> >> >>> > In
>> >> >> >>> > any
>> >> >> >>> > case, I actually think this it's preferable this way.  There's
>> >> >> >>> > nothing
>> >> >> >>> > really about the two that benefits from having them coupled
>> >> >> >>> > together, as far
>> >> >> >>> > as I can see.   I'm willing to be convinced though, if we can
>> >> >> >>> > figure
>> >> >> >>> > out how
>> >> >> >>> > to to do it so that we can still ship it on the marketplace.
>> >> >> >>> "There's nothing really about the two that benefits from having
>> >> >> >>> them
>> >> >> >>> coupled together,"
>> >> >> >>>
>> >> >> >>> The toolset needs to know at least where to find the toolchain
>> and
>> >> >> >>> how
>> >> >> >>> to
>> >> >> >>> invoke it. If we decouple them, there needs to be an interface
>> >> >> >>> between
>> >> >> >>> them
>> >> >> >>> that can't change: in this case the LLVM path and version
>> number in
>> >> >> >>> the
>> >> >> >>> registry.
>> >> >> >>
>> >> >> >> Has that ever changed?  Doesn’t seem too onerous, using the
>> registry
>> >> >> >> is
>> >> >> >> the windows way anyway, if anything this feels like the proper
>> way.
>> >> >> >>
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> But at the same time you're baking in all this logic in the
>> toolset
>> >> >> >>> about
>> >> >> >>> how to invoke the toolchain, what flags are supported, etc.
>> Those
>> >> >> >>> things are
>> >> >> >>> strongly dependent on the toolchain, which in this de-coupled
>> world
>> >> >> >>> seems
>> >> >> >>> problematic. It seems like you're actually making the coupling
>> >> >> >>> tighter
>> >> >> >>> in
>> >> >> >>> that way, except you still want to ship the two parts
>> separately.
>> >> >> >>>
>> >> >> >>> Are there restrictions in the marketplace about how big a vsix
>> can
>> >> >> >>> be?
>> >> >> >>> Because if not, I think we could just package up
>> >> >> >>> clang+headers+runtime
>> >> >> >>> into
>> >> >> >>> a vsix and ship the whole thing, and maybe that would be the
>> best
>> >> >> >>> thing.
>> >> >> >>
>> >> >> >> An installer is very large though, and even if it’s allowed it’s
>> >> >> >> kind
>> >> >> >> of
>> >> >> >> obnoxious to have to download a large amount of stuff if only one
>> >> >> >> thing
>> >> >> >> changes.  Being able to push changes to the Integration
>> >> >> >> independently
>> >> >> >> of an
>> >> >> >> llvm release seems like a feature to me.
>> >> >> >>
>> >> >> >>  coupling it would also make it more difficult to use a custom
>> built
>> >> >> >> llvm
>> >> >> >> toolchain, i can just change a registry setting right now and
>> it’s
>> >> >> >> good
>> >> >> >> to
>> >> >> >> go.  Even the builtin VS toolchains use the registry to locate
>> >> >> >> paths,
>> >> >> >> and we
>> >> >> >> were already reading the registry before this anyway
>> >> >> >>
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> Or we could just stick to the current installer version and
>> make it
>> >> >> >>> a
>> >> >> >>> little smarter about finding VS2017. Maybe instead of the batch
>> >> >> >>> files
>> >> >> >>> we
>> >> >> >>> write an actual program that finds the installation and copies
>> the
>> >> >> >>> files.
>> >> >> >>
>> >> >> >> I definitely think vsix is the way to go.  I’d hate to stick with
>> >> >> >> batch
>> >> >> >> files and not use the proper method of having an extension.  It’s
>> >> >> >> also
>> >> >> >> more
>> >> >> >> discoverable as an extension on the marketplace.
>> >> >> >>
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> ================
>> >> >> >>> Comment at: llvm/tools/msbuild/LLVM.props:8
>> >> >> >>> +    <!-- Friendly names added to the PlatformToolset in the
>> >> >> >>> property
>> >> >> >>> pages. -->
>> >> >> >>> +    <_PlatformToolsetFriendlyNameFor_llvm
>> >> >> >>> Condition="'$(_PlatformToolsetFriendlyNameFor_llvm)' ==
>> ''">Clang
>> >> >> >>> for
>> >> >> >>> Windows</_PlatformToolsetFriendlyNameFor_llvm>
>> >> >> >>> +  </PropertyGroup>
>> >> >> >>> ----------------
>> >> >> >>> zturner wrote:
>> >> >> >>> > hans wrote:
>> >> >> >>> > > Hmm, we previously intentionally called the toolset "LLVM"
>> with
>> >> >> >>> > > the
>> >> >> >>> > > thinking that it would eventually include lld and designated
>> >> >> >>> > > the
>> >> >> >>> > > complete
>> >> >> >>> > > llvm toolchain, not just Clang. And is the "for Windows"
>> part
>> >> >> >>> > > necessary?
>> >> >> >>> > Do you think there's any value in having a toolset that does
>> >> >> >>> > Clang+Link
>> >> >> >>> > and a second one that does Clang+LLD?  Or do you think we
>> should
>> >> >> >>> > stick with
>> >> >> >>> > only a single one?  I can change the name to LLVM though.
>> >> >> >>> The best would be to only have one, but where the user could
>> select
>> >> >> >>> between the two linkers, I think.
>> >> >> >>
>> >> >> >> Yea.  Can try that in a followup, may be tricky though
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> ================
>> >> >> >>> Comment at: llvm/tools/msbuild/Toolset.targets:38
>> >> >> >>> +
>> >> >> >>> +    <!-- Warn if Fiber Safe Optimizations are enabled, and then
>> >> >> >>> ignore
>> >> >> >>> them. -->
>> >> >> >>> +    <Warning
>> >> >> >>> Condition="'%(ClCompile.EnableFiberSafeOptimizations)'
>> >> >> >>> ==
>> >> >> >>> 'true'"
>> >> >> >>> ----------------
>> >> >> >>> zturner wrote:
>> >> >> >>> > hans wrote:
>> >> >> >>> > > This seems to duplicate a lot of logic from clang-cl. It's
>> nice
>> >> >> >>> > > to
>> >> >> >>> > > provide a good UI for the user, but maintaining this seems a
>> >> >> >>> > > lot
>> >> >> >>> > > of work.
>> >> >> >>> > > Are you not concerned that this will rot?
>> >> >> >>> > I don't think it will.  Maybe I'm being overly optimistic
>> here,
>> >> >> >>> > but
>> >> >> >>> > the
>> >> >> >>> > only case we would ever need to maintain this again is if we
>> >> >> >>> > started
>> >> >> >>> > supporting these options.  Fiber Safe Optimizations, for
>> example,
>> >> >> >>> > I'm pretty
>> >> >> >>> > sure we will never support.  If MSVC ever removes the option,
>> for
>> >> >> >>> > example,
>> >> >> >>> > we can do nothing and continue to work.
>> >> >> >>> >
>> >> >> >>> > We could also just silently ignore them and just pass the
>> option
>> >> >> >>> > through to clang-cl, but these are pretty unusual options with
>> >> >> >>> > pretty
>> >> >> >>> > specialized use cases, so I feel like if I had gone out of my
>> way
>> >> >> >>> > to
>> >> >> >>> > enable
>> >> >> >>> > such a strange option I would want to know if the compiler was
>> >> >> >>> > not
>> >> >> >>> > going to
>> >> >> >>> > respect it.
>> >> >> >>> I feel pretty strongly that we should handle this clang-cl
>> side. If
>> >> >> >>> a
>> >> >> >>> flag is not supported, either we should ignore it, or if it's
>> >> >> >>> something the
>> >> >> >>> user would want to know about us not supporting, we should warn.
>> >> >> >>> That's what
>> >> >> >>> clang-cl tries to do currently, and if there are flags we don't
>> get
>> >> >> >>> right,
>> >> >> >>> we should fix it.
>> >> >> >>>
>> >> >> >>> And we do move flags from the unsupported to supported category
>> now
>> >> >> >>> and
>> >> >> >>> then, so the "only case we would ever need to maintain this
>> again
>> >> >> >>> is
>> >> >> >>> if we
>> >> >> >>> started supporting these options" scenario is real.
>> >> >> >>
>> >> >> >> It’s not a matter of clang-cl doing it right or wrong, it’s that
>> >> >> >> there
>> >> >> >> are
>> >> >> >> other moving parts before it even gets to clang-cl.
>> Specifically,
>> >> >> >> MSBuild.
>> >> >> >> We’ve already seen one example of how  just letting clang-cl do
>> its
>> >> >> >> thing is
>> >> >> >> insufficient, and nothing we can ever do in clang-cl can fix
>> that.
>> >> >> >> Given
>> >> >> >> that it’s required sometimes, and that doing it for all options
>> >> >> >> doesn’t
>> >> >> >> increase our maintenance burden, i think it makes sense to do it
>> >> >> >> everywhere
>> >> >> >> and never have to deal with msbuild issues again.
>> >> >> >>
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> ================
>> >> >> >>> Comment at: llvm/tools/msbuild/Toolset.targets:46
>> >> >> >>> +             File="@(ClCompile)(0,0)"
>> >> >> >>> +             Text="clang-cl does not support MSVC Link Time
>> >> >> >>> Optimization.  Disable this option in compatibility settings to
>> >> >> >>> silence this
>> >> >> >>> warning."/>
>> >> >> >>> +
>> >> >> >>> ----------------
>> >> >> >>> zturner wrote:
>> >> >> >>> > hans wrote:
>> >> >> >>> > > But maybe we want clang-cl to map this to -flto one day.
>> Now we
>> >> >> >>> > > need
>> >> >> >>> > > to update two places. And with the toolset/toolchain install
>> >> >> >>> > > split, the two
>> >> >> >>> > > places may be installed separately :-/
>> >> >> >>> > That's even better then.  All we have to do is change this
>> xml,
>> >> >> >>> > push
>> >> >> >>> > a
>> >> >> >>> > new build to the market place, and the VS UI will update their
>> >> >> >>> > extension for
>> >> >> >>> > them.
>> >> >> >>> >
>> >> >> >>> > Note that we could do the mapping at the MSBuild level, in
>> this
>> >> >> >>> > file
>> >> >> >>> > down below where we have an `ItemGroup`.  Just add a line that
>> >> >> >>> > says
>> >> >> >>> > `<AdditionalOptions
>> >> >> >>> > Condition="%(ClCompile.WholeProgramOptimization)' ==
>> >> >> >>> > 'true'>-flto=thin %(AdditionalOptions)</AdditionalOptions>`
>> >> >> >>> >
>> >> >> >>> > and we can do this without touching clang.
>> >> >> >>> But the toolset is decoupled from the toolchain in your
>> proposal.
>> >> >> >>>
>> >> >> >>> Not only would we need to update both clang-cl and this file,
>> but
>> >> >> >>> this
>> >> >> >>> file would need to handle clang-cl versions both before and
>> after.
>> >> >> >>
>> >> >> >> We wouldn’t have to update clang-cl.  We could map ltcg to
>> >> >> >> -flto=thin
>> >> >> >> in
>> >> >> >> the extension and it would automatically work with the installed
>> >> >> >> toolchain.
>> >> >> >>
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> ================
>> >> >> >>> Comment at: llvm/tools/msbuild/Toolset.targets:83
>> >> >> >>> +
>> >> >> >>> +    <!-- Warn if XML Documentation is generated, and then
>> ignore
>> >> >> >>> it.
>> >> >> >>> -->
>> >> >> >>> +    <Warning
>> >> >> >>> Condition="'%(ClCompile.GenerateXMLDocumentationFiles)'
>> >> >> >>> ==
>> >> >> >>> 'true'"
>> >> >> >>> ----------------
>> >> >> >>> zturner wrote:
>> >> >> >>> > hans wrote:
>> >> >> >>> > > Keeping up with all these flags seems like a huge amount of
>> >> >> >>> > > work.
>> >> >> >>> > > Why
>> >> >> >>> > > not just let clang-cl ignore it?
>> >> >> >>> > See the large comment at the top of the file.  For some
>> options,
>> >> >> >>> > we
>> >> >> >>> > could probably get by with this.  Maybe even this one, I
>> debated
>> >> >> >>> > on
>> >> >> >>> > this
>> >> >> >>> > particular one.
>> >> >> >>> >
>> >> >> >>> > My bar was "If the option fundamentally changes assumptions
>> about
>> >> >> >>> > the
>> >> >> >>> > way code could be compiled, we should generate an error.  If
>> it
>> >> >> >>> > changes the
>> >> >> >>> > behavior of the language in a way we don't support,  changes
>> the
>> >> >> >>> > way
>> >> >> >>> > we
>> >> >> >>> > generate code in a meaningful way, or causes specialized
>> output
>> >> >> >>> > files to be
>> >> >> >>> > written, warn, and if it's an option we ignore then drop it"
>> >> >> >>> >
>> >> >> >>> > The last category there we could probably just pass through in
>> >> >> >>> > some
>> >> >> >>> > cases, but in that comment I also mentioned a case where
>> setting
>> >> >> >>> > an
>> >> >> >>> > option
>> >> >> >>> > that clang-cl ignores impacts MSBuild's ability to figure out
>> >> >> >>> > dependencies
>> >> >> >>> > and ends up causing a full rebuild every time even when
>> nothing
>> >> >> >>> > changed.
>> >> >> >>> >
>> >> >> >>> > We can scour the entire cl build tasks and try to discover if
>> any
>> >> >> >>> > other
>> >> >> >>> > ones have unintended consequences, but I think it's easier to
>> >> >> >>> > just
>> >> >> >>> > turn them
>> >> >> >>> > off at the MSBuild level.  And as a side benefit, the user
>> gets
>> >> >> >>> > shorter
>> >> >> >>> > command lines, which is always nice.
>> >> >> >>> >
>> >> >> >>> > As for maintenance, this all looks like zero-maintenance code
>> to
>> >> >> >>> > me.
>> >> >> >>> > Did you have an example in mind of where we'd need to update
>> >> >> >>> > this?
>> >> >> >>> > Whether
>> >> >> >>> > it be a new VS version, or VS dropping support for one of
>> these
>> >> >> >>> > options or
>> >> >> >>> > deprecating them, I don't think we'd have to do anything.
>> >> >> >>> The maintenance would come from when clang-cl changes how it
>> >> >> >>> handles
>> >> >> >>> some
>> >> >> >>> option, or when VS adds new options.
>> >> >> >>
>> >> >> >> But these are all really obscure options that we will probably
>> never
>> >> >> >> touch.  When vc adds new options we’re not obligated to update
>> this
>> >> >> >> file
>> >> >> >> either.
>> >> >> >>
>> >> >> >>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>>
>> >> >> >>> ================
>> >> >> >>> Comment at: llvm/tools/msbuild/install.bat:10
>> >> >> >>> +REM Older versions of VS would look for these files in the
>> Program
>> >> >> >>> Files\MSBuild directory
>> >> >> >>> +REM but with VS2017 it seems to look for these directly in the
>> >> >> >>> Visual
>> >> >> >>> Studio instance.
>> >> >> >>> +REM This means we'll need to do a little extra work to properly
>> >> >> >>> detect
>> >> >> >>> all the various
>> >> >> >>> ----------------
>> >> >> >>> zturner wrote:
>> >> >> >>> > hans wrote:
>> >> >> >>> > > Don't we want to support at least 2015 too?
>> >> >> >>> > Mentioned in the other review, but the install.bat file
>> shouldn't
>> >> >> >>> > really be used anymore except for during development.  The
>> VSIX
>> >> >> >>> > supports
>> >> >> >>> > both 2015 and 2017 (I tested it in both and confirmed it
>> works)
>> >> >> >>> Hmm, but then we should delete it, or at least take it out of
>> the
>> >> >> >>> installer, and we need a replacement. As it is now, if we land
>> >> >> >>> this,
>> >> >> >>> it
>> >> >> >>> breaks the installer for versions before 2017.
>> >> >> >>
>> >> >> >>
>> >> >> >> I thought i took it out of the installer, but maybe I missed
>> >> >> >> something.
>> >> >> >> We still need it for dev purposes because it allows us to
>> overwrite
>> >> >> >> the
>> >> >> >> existing installed version with new files
>> >> >> >
>> >> >> >
>> >> >> > _______________________________________________
>> >> >> > llvm-commits mailing list
>> >> >> > llvm-commits at lists.llvm.org
>> >> >> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>> >> >> >
>>
>
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