julia

036d6404 - staticdata: pack CodeInstances at the front of precomposed sysimages

staticdata: pack CodeInstances at the front of precomposed sysimages After the previous two commits, the only load-time relocations left in a precomposed system image are native function pointers (FunctionRef), which live exclusively in CodeInstances -- as do the stores made by jl_update_all_fptrs and most runtime mutation of image objects during startup (flags and world-age updates). Serializing all CodeInstances first therefore confines nearly every load-time and startup store to a small contiguous region at the front of the image. Only the physical write order changes: cross-references go through layout_table (indexed by queue id), the relocation lists are pushed in stream-position order regardless of visit order, and the queue itself is untouched, so incremental-image semantics are unaffected (the reordering is only applied to precomposed images anyway). In the test sysimage, the pages touched by external relocations drop from 2265 to 604 (the ~9.4MB CodeInstance region), dirty pages in the mapped .ji drop from ~70MB to ~13MB of 161MB, and startup at the preferred address improves from 41.3ms to 29.3ms (slide fallback: 51.8ms; classic embedded sysimage: ~78ms), largely from the reduced copy-on-write faulting. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>