On 06/08/2017 02:28 PM, Joseph Myers wrote: > genmultilib computes combination_space, a list of all combinations of > options in MULTILIB_OPTIONS that might have multilibs built for them > (some of which may end up not having multilibs built for them, and > some of those may end up being mapped to other multilibs with > MULTILIB_REUSE). It is then used to validate the right hand part of > MULTILIB_REUSE rules, checking with expr that combination_space > matches a basic regular expression derived from that right hand part. > > There are two problems with this approach to validation: > > * It requires that right hand part to have options in the same order > as in MULTILIB_OPTIONS, in contradiction to the documentation of > MULTILIB_REUSE saying that order does not matter there. > > * combination_space can be so large that the expr call fails with an > E2BIG error. I have a local ARM configuration with 40 multilibs but > 3840 combinations of options from MULTILIB_OPTIONS (so 3839 listed > in combination_space, since it doesn't list the default multilib) > and 996 MULTILIB_REUSE rules. This generates a combination_space > string longer than the Linux kernel's MAX_ARG_STRLEN (PAGE_SIZE * > 32, the limit on the length of a single argv string), so that expr > cannot be run. > > This patch changes the validation approach to generate a much shorter > extended regular expression for any sequence of multilib options in > any order, and uses that for the validation instead. > > Tested with a built for arm-none-eabi --with-multilib-list=aprofile > (as a configuration that uses MULTILIB_REUSE). > > 2017-06-08 Joseph Myers <jos...@codesourcery.com> > > * genmultilib (combination_space): Remove variable. > Validate reuse rules against regular expression for any sequence > of multilib options in any order. Going to trust you on this :-) regexps are far from my sweet spot.
jeff
