Builds on the source-built-RTL link path. Two correctness fixes plus the
fixpoint-script migration that takes the self-host pipeline off blaise_rtl.a.
1. Symbol-based dedup. A program that uses an RTL unit (e.g. `uses classes`
pulls runtime.arc) compiles that unit into its own object cache, so
EnsureRTLObjects must not supply a second copy or the link double-defines it.
The dedup now compares the DEFINED symbols of the caller's objects against
each RTL object (via the ELF reader) and skips one only when fully redundant
— matching the old archive's member selection. An earlier filename-only
check wrongly suppressed the real bare-symbol provider when a same-named but
differently-mangled stale object was present.
2. Race-free build. EnsureRTLObjects now builds into a per-process private
directory (rtl/build-<pid>/) and atomically renames each finished object
into the shared cache. Parallel builders (e.g. e2e suites warming a cold
cache) no longer corrupt each other: a reader never sees a half-written
object, and two builders just publish identical results. The private dir is
cleaned up afterwards. getpid/rmdir are declared directly rather than via
GRtlPlatform to avoid a unit-init-order crash in the driver.
3. Fixpoint scripts off the archive. New scripts/build-rtl-objects.sh builds
the RTL from source (the script-level equivalent of EnsureRTLObjects), with
--exclude-defined-by so a whole-program --emit-ir/--emit-asm dump (which
inlines the RTL units the compiler uses) is not handed a duplicate copy.
fixpoint.sh and fixpoint-native.sh link via this helper instead of
blaise_rtl.a; fixpoint-native-internal.sh and fixpoint-warmcache.sh no longer
copy the archive beside the compiler (the driver source-builds the RTL).
All four fixpoints green (FIXPOINT_OK, NATIVE_FIXPOINT_OK, NATIVE_INTERNAL_OK,
WARMCACHE_FIXPOINT_OK); full suite green (3829 tests) under QBE- and
native-built runners; four cold-cache parallel suite runs pass.
The runtime Makefile / ar / make install are still present; removing them is the
final Stage-3 step.
When a unit's source content changed, it was correctly recompiled from a warm
--unit-cache, but a cached unit that USES it kept its cached interface and was
imported in the cached-iface phase — which runs BEFORE source-recompiled units
are analysed. Importing the cached dependent then failed to resolve a type
defined only by the not-yet-analysed dependency, raising EImportError (empty
message), e.g. editing blaise.codegen.driver and rebuilding the whole compiler
warm broke on blaise.frontend.opts (TBackendKind unresolved). The same
corrupted warm cache also produced an intermittent SIGSEGV in the e2e runner.
uUnitLoader now tracks units taken via the source path (FSourceLoadedNames).
In the cached path, after recursing into a unit's interface-use dependencies,
if any dependency was source-loaded the cached iface is discarded and the unit
is recompiled from source too, so it is analysed after its dependency.
Post-order DFS makes this transitive.
fixpoint-warmcache.sh now edits a dependency unit's content between its two
builds (previously two clean fills that never exercised staleness propagation);
it FAILS on the pre-fix compiler and PASSES on the fixed one.
None of the existing fixpoint scripts exercise the incremental warm-cache
rebuild path: fixpoint.sh uses --emit-ir (no cache), fixpoint-native.sh diffs
.s (no cache), fixpoint-native-internal.sh compiles a tiny program. So a
regression in the cached-interface import/round-trip (dropped field, wrong
vtable slot, duplicate global, missing init) passes all of them and only
surfaces later as a corrupt binary — exactly the class of bug just fixed.
scripts/fixpoint-warmcache.sh builds the whole compiler twice into the same
--unit-cache (clean then warm), asserts the warm rebuild is non-empty and not
drastically smaller than the clean build, and compiles+runs hello-world with
both stage-2 binaries to prove the warm-cache-rebuilt compiler is correct, not
just present. Prints WARMCACHE_FIXPOINT_OK on success.
mzhoot
