Start alpha development with an opt-in Whale IR backend

[LunaStev]

Summary

Start 0.0.1-alpha-dev development with an opt-in Whale IR backend. Add a root whale/ workspace crate alongside llvm/; the compiler driver retains CLI dispatch and source preparation. The existing --whale flag now supports check and build --emit=ir, producing verified .wir files.

Whale IR comes from official wavefnd/Whale master, with commit 4f45fdb53d07882932cc251856316206a3bb3947 recorded in Cargo.lock. The adapter consumes Wave typed HIR calculation types and ordered conversions, preserves short-circuit evaluation, and uses iterative expression traversal to retain the 128-level nesting boundary on a 1 MiB stack.

The PR also refreshes the Nightly deployment pins for the latest-only installers from wavefnd/wave-platform#476. Both live installer downloads exactly match the new hashes. The old hashes match the earlier #473 scripts and would now reject the deployed installers in both the Nightly gate and publication checks. The diagnostic wording is updated to describe the latest-only policy; hash verification remains unchanged.

Motivation

Begin LLVM/Whale coexistence for alpha while keeping the existing LLVM compiler usable. This is an initial integration toward #93, not completion of backend parity.

Target and compatibility impact

• LLVM remains the default; no new backend selection syntax is introduced.
• Whale currently supports Linux amd64 at O0 for IR generation and verification. Scalar functions, direct calls, initialized local variables, assignments, conditionals, loops, and the supported scalar operations are lowered.
• Executable/object/assembly output, unsupported targets, and unsupported language operations produce explicit diagnostics instead of falling back to LLVM. Source diagnostics retain the existing JSON format and source spans; failed lowering preserves existing output files.
• The development version changes to 0.0.1-alpha-dev; no release is published and the compiler/std compatibility revision remains unchanged.

Validation

Using CI-pinned Rust 1.89 and LLVM_SYS_211_PREFIX=/usr/lib64/llvm21 where LLVM is needed:

cargo +1.89 check --offline --jobs 2 -p whale
cargo +1.89 test --locked --offline --jobs 2 --no-default-features --features llvm-target-core64 --test whale_backend
cargo +1.89 clippy --locked --offline --jobs 2 -p whale --all-targets -- -D warnings
cargo +1.89 clippy --locked --offline --jobs 2 --no-default-features --features llvm-target-core64 --all-targets -- -D warnings
RUSTDOCFLAGS='-D warnings' cargo +1.89 doc --locked --offline --workspace --no-default-features --features llvm-target-core64 --no-deps --jobs 2
cargo +1.89 fmt --all --check
git diff --check
python3 -m unittest tools.test_nightly

All 27 Nightly tests pass, and both live installer SHA-256 values match nightly_installers.json. All eight Whale integration regressions pass, covering control flow/calls, ordered casts, contextual wide literals, float-to-bool handling, output protection, unsupported requests, LLVM remaining the default, and the 128/129 expression-depth boundary. The Whale crate builds independently without an LLVM dependency.

Exploratory Rust 1.96 checks exposed a small-stack frontend failure also reproduced on unmodified master, plus a warning in unchanged WSON code. The passing checks above use the repository's pinned Rust 1.89.

Checklist

• Commits include a DCO Signed-off-by line.
• Tests cover new behavior or the PR explains why no test is needed.
• User-facing changes include documentation or diagnostics updates.
• The change preserves the license boundary between the compiler and std/.

Issues

Closes #861.

Related to #93 and #773.