On Mon, Apr 22, 2019 at 2:14 AM Jakub Jelinek <ja...@redhat.com> wrote: > > As detailed in the PR, unlike most other targets, on ARM EABI the floating > point registers are saved lazily, when EH personality routine calls > __gnu_unwind_frame (usually in the CONTINUE_UNWINDING macro). > That means the unwinder itself and the personality routines (and whatever > other functions those call in the path to CONTINUE_UNWINDING) must be > compiled so that it doesn't use floating point registers. Calling some > function that saves those on entry and restores on exit is fine, but calling > some function which saves those on entry and then calls __gnu_unwind_frame > and then restores on exit is not fine. > In 8.x and earlier we were just lucky that the RA when compiling those > didn't decide to use any of those registers, but starting with the combiner > hard register changes we are no longer so lucky. > > The following patch introduces -mgeneral-regs-only option and > general-regs-only target attribute for ARM (similarly to how other targets > like AArch64 and x86), changes the ARM unwinder to be compiled with that > and changes the personality routines of all languages so that either just > the personality routine, or whatever other routines called by personality > routines that call directly or indirectly __gnu_unwind_frame to be compiled > that way. > > Bootstrapped/regtested on armv7hl-linux-gnueabi (and x86_64-linux to make > sure it compiles on other targets too). > > Ok for trunk? > > While the libgo changes are included in the patch, I think those need to go > through go upstream and will likely need some changes if that code can be > compiled by earlier GCC versions or other compilers.
Thanks. I've committed the libgo changes. (Older versions of GCC have their own copy of libgo, and there are not yet any non-GCC compilers that use this code and support ARM.) Ian
