On 7 Sep 2016, at 15:21, Hannes Mehnert <[email protected]> wrote: > > On 07/09/2016 15:08, Anil Madhavapeddy wrote: >> I'd prefer to allocate and have a good API, but then I would also prefer to >> not use compiler builtins that may introduce subtle optimisation bugs in the >> future -- or at least until we know that the optimisations are useful. >> >> E.g. the double fetch vulnerabilities that emerged from compiler builtins >> https://xenbits.xen.org/xsa/advisory-155.html (not directly applicable here, >> but my point is that I'd prefer a slightly slower but more consistent first >> cut at this library) > > I don't see the relation between builtins and compiler optimisations, > but I might lack knowledge about the bug. Looking into some patches, > such as > https://xenbits.xen.org/xsa/xsa155-linux43-0005-xen-blkback-read-from-indirect-descriptors-only-once.patch > it has not much to do with builtins. > > My first cut of this library was to use the builtins, since they're > available on all platforms I care about, but then Travis CI turned to be > unhappy (since it seems most Linux distributions ship arcane versions of > gcc). >
Sadly we do have to support GCC3/4 for some time in core libraries (e.g. OpenBSD base uses the last GPLv2 version of GCC3 in base)... Anil _______________________________________________ MirageOS-devel mailing list [email protected] https://lists.xenproject.org/cgi-bin/mailman/listinfo/mirageos-devel
