Local compiler development loop

The repository is a UMS project whose build.ums names .prismio/build/debug/prismio as its project-local compiler host. The installed parent reads the bootstrap-safe host block through umsProjectHost(); when the host is absent it performs the build itself, and when it exists dispatchToUmsHost() forwards the original argument vector to that binary.

Ordinary loop

prismio check src/main.psm
prismio build
PRISMIO=$PWD/.prismio/build/debug/prismio python3 tests/test_runner.py

buildUmsProject() loads the workspace, selects the profile, creates the build plan, and notices when the output target is the running host. The new executable is linked at a staged path. Only after a successful build does the parent replace the project host. The running compiler never opens its own executable for output, and a parse, sema, LLVM, or link failure leaves the previous host usable.

After the first promotion, repeat prismio build to exercise forwarding through the new host. Use prismio --version and the printed compiler path to verify which generation received a direct single-file command; shell PATH alone is not sufficient evidence.

Focused tests while editing

The Python runner accepts names without compiling the entire suite:

PRISMIO=$PWD/.prismio/build/debug/prismio \
  python3 tests/test_runner.py test_92_field_view_provenance

Set PRISMIO_TEST_JOBS=1 for a deterministic log when failures interleave. Use python3 tests/test_runner.py --list to discover registered names. The runner resolves PRISMIO before PATH and prints the chosen executable.

Use named generations for reproducibility

Bootstrap, seed refresh, and fixed-point work should use build/genN outputs rather than the moving debug host. tools/bootstrap.sh --compiler build/gen1 --out build/gen2 gives each generation an immutable path; tools/release_gate.py --rc build/gen2 independently rebuilds successors and compares their IR. Record the exact compiler path in bug reports and benchmark results.

Trace or bypass caches

PRISMIO_BUILD_TRACE=1 prints build phases, including library bitcode merge. PRISMIO_OBJ_CACHE_TRACE=1 exposes cache hits and misses; PRISMIO_OBJ_CACHE=0 bypasses the object cache, which serves the bootstrap and toolchain-source paths — an ordinary program build compiles no C and produces no cache entries. There is no switch that disables the library bitcode merge; PRISMIO_INLINE_RUNTIME is retired and ignored. These are diagnostic switches, not alternative supported build semantics. Reproduce once with defaults before attributing a bug to the bypassed component.

Before committing

Run the relevant focused test while iterating, then the full test suite. Changes to code generation, the runtime, bootstrapping, or embedded sources also require generation agreement and packaging checks. Changes to diagnostics should validate both human and JSON forms. Changes to AIF should exercise reports, manifests, the independent oracle, and runtime verification where applicable.