[R-pkg-devel] Compiler warning using C versions of base R integrate function

[Devin Incerti]

Thank you, Tomas, that is very helpful.

On Thu, Nov 28, 2019 at 4:41 AM Tomas Kalibera <tomas.kalibera using gmail.com>
wrote:

> On 11/21/19 7:25 PM, Devin Incerti wrote:
> > Hi,
> >
> > I'm attempting to submit a very minor update to my package where I
> replaced
> > a deprecated C++ function with an alternative. However, I'm receiving an
> > unrelated warning "*array subscript -1 is outside array bounds of ‘double
> > [52]’ [-Warray-bounds] *" on Debian during the CRAN pre-tests. I do not
> > receive this warning on my local OS X, Ubuntu 16.04 (on Travis-CI), with
> > Win-builder, or with R-hub builder. I also did not receive this warning
> on
> > previous submissions to CRAN, but it does now show up on the most recent
> CRAN
> > checks
> > <
> http://s.bl-1.com/h/cH9zB21r?url=https://cran.r-project.org/web/checks/check_results_hesim.html
> >
> > .
> >
> > The warning is related to the header file integrate.h
> > <
> http://s.bl-1.com/h/cH9zB6Qt?url=https://github.com/hesim-dev/hesim/blob/master/inst/include/hesim/Rbase/integrate.h
> >,
> > which is just integrate.c
> > <
> http://s.bl-1.com/h/cH9zBCpw?url=https://github.com/wch/r-source/blob/5a156a0865362bb8381dcd69ac335f5174a4f60c/src/appl/integrate.c
> >
> > from
> > R source with function pointers replaced by C++ functors. These
> integration
> > functions are needed so that the package can integrate at the C++ level.
> >
> > I don't know how to avoid this warning. Is it perhaps related to the
> > particular version of GCC used during the CRAN checks. Any thoughts or
> > suggestions would be much appreciated.
> >
> > Thank you!
>
> The warning is generated by GCC when inlining the function rdqelg(), I
> can reproduce it with the integrate.c we have in R, but only if I add
> "inline" to rdqelg() definition (GCC 6 and newer - on Ubuntu but that
> should not matter). The inliner knows the callsite, so it knows that
> what is being passed is an array (and not an arbitrary pointer), and
> hence it emits the warning. It is not smart enough to know that the
> first element of the new "array" will (unless there is a bug) never be
> used. When not inlining and the function is compiled independently from
> its callsites, it assumes it is a pointer, and hence there is no warning.
>
> The code is automatically converted from Fortran, maybe these pointer
> decrements in function prologues are to adjust to Fortran 1-based array
> indexing. If you must use this modified copy of integrate.c from R,
> perhaps a quick hack to get rid of the warning would be to avoid the
> "inline" keywords in declarations of functions like rdqelg(). In a
> perfect world, the code would be rewritten to more idiomatic C (not just
> to avoid these decrements). Or perhaps the Fortran original could be used.
>
> Tomas
>
> > ()
> >
> > Devin
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-package-devel using r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-package-devel
>
>
>

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