The emitter writes "; scriptc-entry" before the entry module's top-level
function (its %init). In modules of fewer than 32 partitions, the helper
places the roots that hold a marked function first, and their partitions
take no other root. A root that finds no partition with room goes to the
first open partition from its own.
An edit of the program's top level then recompiles only the top-level code
and the chain that follows it, not the other roots that balancing placed
beside it.
The early executable cache key covered the profile but not the function
layout, so a build that added, changed or edited a layout could restore
the executable built with the previous order. The key now includes the
digest of the layout file's bytes. An unreadable layout fails the build
with SC3002 before the cache lookup.
A warm rebuild ran about 3.5 MB of the native compiler's code, but the code
was spread over its 69 MB text, so 64 KB fault-around mapped about 20 MB of
it. The emitter can now take a function layout: a list of functions in
tiers. It writes the listed definitions, generated helpers included, first
and by tier, each in a `layout-<tier>` partition group. The LLVM helper
compiles each partition's definitions in text order, so the listed ones
come first in their partitions, and a helper that places functions by
group keeps a tier's definitions in the same partitions. The rest keep
their order and their source-file groups.
- compile() takes a `functionLayout` file (`<tier> <symbol>` lines,
gzip-compressed when the name ends in .gz). Keys leave out module
numbers.
- build-native-cli.mts uses the committed packages/compiler/native/cli.layout.gz,
or the file SCRIPTC_NATIVE_LAYOUT names; an empty value and instrumented
builds use none.
- scripts/refresh-cli-layout.mjs builds an instrumented compiler, builds
the runtime workloads and a corpus slice cold and then unchanged, and
reads the functions each run executed from the raw profiles. Tier 1 is
`--version` and rebuilds that hit both caches; tier 2 is the other builds.
- The release workflow's cli-profile job also collects a layout on the
release commit, and the CLI builds use it. Names of closures and
generated helpers change with nearby edits, so a committed layout
matches fewer functions as main moves on.
- Forked lowering and emission workers reset the profile counters after
fork and write their profile before _exit, so instrumented builds also
count the work done in workers. This applies to refresh-cli-profile.mjs
too.
Executables the compiler produces are unchanged.
Chris Tate