Chunked emission replays every numbered helper a range creates on the
merging emitter. The jsval entry thunks (dyn.jsEntryThunk) were missing
from the replayed dyn helpers, so a range that boxed a closure with a
jsval body failed to merge.
The committed runtime profile named the runtime ABI marker
scr_runtime_abi_v47, which ABI 48 renames to scr_runtime_abi_v48. The
profile's record now carries the new name; its hash and counts are
unchanged.
The string spare, the main thread's idle trim and the shared-bytes writes
changed runtime functions that hold enough of the committed profile's counts
to fail its staleness check (7.3% against a 5% limit). The profile is
collected again on this change with scripts/refresh-runtime-profile.mjs
(327 raw profiles), with the LLVM helper built from this tree's sources.
scr_str_case_conv scans ASCII text for the first letter to convert eight
bytes at a time, then converts the rest eight bytes at a time; the tail
and big-endian targets take the byte loop. With a refreshed profile, the
byte-at-a-time scan compiled worse for short strings with nothing to
convert, which made validate-errors slower.
The runtime profile is collected again on this change with
scripts/refresh-runtime-profile.mjs (326 raw profiles). Changed
functions hold 0.0% of its counts, against 3.7% for the previous one.
tests/corpus/string-case-ascii-words.ts covers ASCII strings of every
length from 0 to 40, with letters at block boundaries and next to the
bytes just outside A-Z and a-z.
The LLVM helper's runtime-unit now optimizes a unit itself (--opt-level),
with IR instrumentation (--profile-generate) or a profile (--profile-use),
through the same pipeline as program code. The Linux x64 pack's speed
units are compiled to unoptimized bitcode and optimized there with
packages/runtime-pack-common/profiles/linux-x64-gnu.profdata.gz, so one
LLVM writes and reads every profile. Release and library flavors are
unchanged. The pack manifest records how the profile matched the units.
Code the runtime profile finds cold is optimized for speed, not size: a
runtime function the training programs rarely call can be hot in another
program. scr_message.c is optimized without the profile.
scripts/refresh-runtime-profile.mjs trains the profile on the runtime
benchmark workloads and, optionally, a tsc-ts checkout, and keeps only the
records of functions the instrumented runtime units define
(merge-profiles --keep-functions). Tests check that the profile still
matches the runtime and names only runtime functions.
Chris Tate