Commit 1d5bb760 authored by Committed by Alan CoopersmithBrowse files
Fix InternalCallbackRec layout if pointers are bigger than 64 bits
When running `xeyes` via `SSH -X` on CHERI-RISC-V FreeBSD, I was getting a Bus Error (unaligned store) in the `cl->callback = callback;` line of _XtAddCallback. The `cl` variable (created using `ToList(icl)`) was only aligned to 8 bytes, but for CHERI-RISC-V pointer-type loads and stores require 16-byte alignment. In order to fix this, I added a C99 flexible array member to internalCallbackRec when compiling for C99 or newer. This ensures that sizeof(InternalCallbackRec) is 16 (since it now includes the required 12 byte padding up to the first XtCallbackRec). This also ensures that alignof(InternalCallbackRec) is 16, but that doesn't matter in this case since malloc() will always return a sufficiently-aligned pointer. I also changed ToList(p) to use the flexible array member directly when compiling for C99. This is not a functional change since it will evaluate to the same pointer, but it does add additional type checking and ensures tha...