On Thu, Apr 12, 2018 at 10:50 PM, Thomas König <t...@tkoenig.net> wrote: > Hello world, > > with Fortran 2018, recursive is becoming the default. This will likely > have a serious impact on many user codes, which often declare large > arrays which could then overflow stacks, leading to segfaults without > further explanation. > > What could we do? A few options, not all mutally exclusive. > > We could extend -fmax-stack-var-size so it allocates memory > from the heap in recursive procedures, too, and set this to > some default value. Of course, it would also have to free them > afterwards, but we manage that for allocatable arrays already. > > We could warn when large arrays with sizes known at compile time > are translated. > > We could use -fsplit-stack by default. How reliable is that > option? Can it be used, for example, with -fopenmp? > Is it available on all (relevant) platforms?
Not available on AArch64 (yet, though there are some patches) and Arm (no current plans that I know of). Probably works best only on x86_64. I don't think you can rely on that being available everywhere. Additionally depending on the implementation IIRC that will have a dependency on a newer glibc as well,so that would depend on a newer glibc as well for split-stack to work reliably as platforms. Ramana
