On 3/8/19 11:07 AM, Mathias Stearn wrote:
>
>
> On Fri, Mar 8, 2019 at 5:45 AM Tom Honermann <tom_at_[hidden]
> <mailto:tom_at_[hidden]>> wrote:
>
> On 3/8/19 2:28 AM, Gabriel Dos Reis via Modules wrote:
> > I prefer the suggestion of a zip file containing the required
> files much better.
>
> The zip approach has advantages in terms of being able to reproduce
> preprocesor issues (assuming the issue doesn't have to do with
> resolving
> header names to files of course).
>
> However, the zip approach doesn't work well for test case reduction
> tools like Delta [1] or C-reduce [2] that need to mutate the
> files. Use
> with them would require exploding the zip. If the zip file contains
> files at absolute paths (e.g., under /usr/include), then the files
> can't
> be exploded to their natural locations thus requiring additional
> modifications to the compiler invocation to use alternate include
> paths
> - which can affect test case reduction.
>
>
> Actually, I would expect it to be *easier* for them. Those tools will
> be able to read the files in the zip (or other format) directly
> without ever writing them to disk. There are plenty of libraries for
> that. If this format is accepted as stdin to compilers, those tools
> should be able to synthesize a new stream in memory and then shove it
> in to the compiler without writing a single file to the filesystem
> until it has found the minimal repro to output. What do you expect
> will make this harder?

These tools operate on single files today. In the zip case, they would
now need to mutate not one file, but the collection of files within the
zip archive.

Tom.

>
> At Coverity, we do a fair amount of test case reduction in this
> way, so
> it is quite important to us.
>
> Tom.
>
> [1]: http://delta.tigris.org/
> [2]: http://embed.cs.utah.edu/creduce/
>
> >
> > — Gaby
> >
> >> On Mar 7, 2019, at 10:23 PM, Tom Honermann <tom_at_[hidden]
> <mailto:tom_at_[hidden]>> wrote:
> >>
> >>> On 3/5/19 11:11 AM, Ben Craig wrote:
> >>> I will concede that static analysis tools and other tools that
> try to parse C++ probably don't need a textual inclusion format,
> since they most likely need to be able to parse and understand the
> pragmas anyway. If module mapping is sufficiently
> straightforward, then those tools can do module lookup the same as
> a compiler. Those tools already need to do include lookup in the
> same way that compilers do.
> >>>
> >>> I think the textual inclusion format will still be very useful
> to distribution and caching tools though, as they don't need to
> understand the code. Those tools frequently lean on the
> compiler's preprocessor today, and don't know how to do include
> lookups.
> >> Another use case is reproducing issues encountered in the
> field. Static analysis tools like Coverity need to emulate other
> compilers. Today, when we fail to parse a TU that the emulated
> compiler accepts, we ask customers to send us preprocessed output
> for reproduction and analysis purposes. We ask for preprocessed
> output because that is much simpler to handle than the entire
> collection of included header files that must then be arranged
> according to some specific compiler invocation and set of include
> paths. We need a solution for this that works for modules as
> well. Clang's -frewrite-imports option so far seems to do the job
> for us and it uses #pragma directives in similar manner to those
> described here. I strongly favor specifying a common set of
> #pragma directives for this purpose.
> >>
> >> Tom.
> >>
> >>>> -----Original Message-----
> >>>> From: Nathan Sidwell <nathanmsidwell_at_[hidden]
> <mailto:nathanmsidwell_at_[hidden]>> On Behalf Of Nathan
> >>>> Sidwell
> >>>> Sent: Tuesday, March 5, 2019 6:04 AM
> >>>> To: Ben Craig <ben.craig_at_[hidden] <mailto:ben.craig_at_[hidden]>>;
> modules_at_[hidden] <mailto:modules_at_[hidden]>; WG21
> Tooling
> >>>> Study Group SG15 <tooling_at_[hidden]
> <mailto:tooling_at_[hidden]>>
> >>>> Subject: [EXTERNAL] Re: [isocpp-modules] Round2: Path to
> modules with old
> >>>> bad build systems
> >>>>
> >>>>> On 3/4/19 10:02 AM, Ben Craig wrote:
> >>>>> I do mean textual inclusion, though I can be convinced
> otherwise. Textual
> >>>> inclusion (with extra generated pragmas) should make it much
> easier to keep
> >>>> tools like distcc and cppcheck happy in the short term. I
> suspect that those
> >>>> tools don't want to crack open a BMI to figure out which
> other BMIs need to
> >>>> be found.
> >>>>> Tools that (think they can) parse C++ will still need to
> understand these
> >>>> pragmas in order to provide the right macro, visibility, and
> reachability
> >>>> behaviors, so some work will still be required on their part,
> but at least they
> >>>> won't need to understand new binary formats.
> >>>>
> >>>> Correct, tools consuming such #pragma-marked flattened source
> will need to
> >>>> understand modules at a fundamental level. As such, why not
> implement
> >>>> the same mechanisms to find module source as the compiler?
> >>>> That'll give them more information to perform code analysis with.
> >>>>
> >>>> nathan
> >>>>
> >>>>>>> On 3/2/19 1:03 PM, Ben Craig wrote:
> >>>>>>>
> >>>>>>> Some quick notes on this implementation strategy:
> >>>>>>> * Uses TEXTUAL inclusion
> >>>>>>> * Compiler assumes that the build system knows nothing of BMIs
> >>>>>>> * Compiler needs to be able to do module mapping with
> minimal input
> >>>>>>> from users.
> >>>>>> Do you literally mean textual inclusion or do you really mean
> >>>>>> dynamically produce an internal-only BMI object?
> >>>>>>
> >>>>>> nathan
> >>>>>>
> >>>>>> --
> >>>>>> Nathan Sidwell
> >>>> --
> >>>> Nathan Sidwell
> >>> _______________________________________________
> >>> Tooling mailing list
> >>> Tooling_at_[hidden] <mailto:Tooling_at_[hidden]>
> >>>
> https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.open-std.org%2Fmailman%2Flistinfo%2Ftooling&amp;data=02%7C01%7Cgdr%40microsoft.com%7C1cdb6c203df64eb7b84408d6a38ea3ab%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636876230368116236&amp;sdata=ugzbdk5BI%2Bppnt5nS0xDISJehZ3mizhZTBWDrVZZ%2BA8%3D&amp;reserved=0
> >>
> >> _______________________________________________
> >> Modules mailing list
> >> Modules_at_[hidden] <mailto:Modules_at_[hidden]>
> >> Subscription:
> https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.isocpp.org%2Fmailman%2Flistinfo.cgi%2Fmodules&amp;data=02%7C01%7Cgdr%40microsoft.com%7C1cdb6c203df64eb7b84408d6a38ea3ab%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636876230368116236&amp;sdata=UPJ70IqxSq6PeLpRdMc7IZCotDOeyV6n7QNxOXjYFQo%3D&amp;reserved=0
> >> Link to this post:
> https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.isocpp.org%2Fmodules%2F2019%2F03%2F0218.php&amp;data=02%7C01%7Cgdr%40microsoft.com%7C1cdb6c203df64eb7b84408d6a38ea3ab%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636876230368116236&amp;sdata=%2BsOB4DmF0Lf6EPmsPij3i%2BsDHDZS3ujHN4S9rVjMer4%3D&amp;reserved=0
> > _______________________________________________
> > Modules mailing list
> > Modules_at_[hidden] <mailto:Modules_at_[hidden]>
> > Subscription: http://lists.isocpp.org/mailman/listinfo.cgi/modules
> > Link to this post: http://lists.isocpp.org/modules/2019/03/0220.php
>
>
> _______________________________________________
> Modules mailing list
> Modules_at_[hidden] <mailto:Modules_at_[hidden]>
> Subscription: http://lists.isocpp.org/mailman/listinfo.cgi/modules
> Link to this post: http://lists.isocpp.org/modules/2019/03/0226.php
>
>
> _______________________________________________
> Modules mailing list
> Modules_at_[hidden]
> Subscription: http://lists.isocpp.org/mailman/listinfo.cgi/modules
> Link to this post: http://lists.isocpp.org/modules/2019/03/0229.php