perry: experimental patches for context-mode native compilation

[bradmccormack]

Experimental patches for context-mode native compilation

This PR is targeted at the personal fork bradmccormack/perry, not upstream PerryTS/perry. It's the same experimental work previously raised (inadvertently) against upstream as PR PerryTS#7225, which has been closed with an apology comment.

Experimental, opt-in. This is a set of small forward-compat patches to perry-hir that let the auto-optimizer's dyn-eval interpreter ride along for KnownLibraryCodegen (ajv, fast-json-stringify, find-my-way) call sites, and that track const F = Function-style aliases of the global Function constructor through the globalThis.Function path. Together they unblock compiling context-mode (a Node.js MCP server) into a native 16 MB binary with node:sqlite + FTS5 + HTTP MCP transport working end-to-end.

Full write-up — including the 7 upstream Perry issues worked around and the file-level diff inventory — is in CONTEXT-MODE-COMPAT.md at the repo root.

Why these patches exist

A real-world downstream consumer (context-mode, the MCP server that lives next to this checkout) compiles fine into Node.js but runs into three concrete gaps in the current perry-hir:

1. The auto-optimizer refuses to link the dyn-eval interpreter when only KnownLibraryCodegen (bucket-2) sites are present. It only consults has_deferred_dynamic_code_sites(). ajv's new Function() then throws at the first call.
2. Zod v4 (and any user code) does const F = Function to keep the global Function constructor reachable. perry-hir did not recognise that as a Function alias, so new F(...) degraded to a user-class new and lost the dyn-eval route.
3. globalThis.Function = <local> style aliases (also a real downstream pattern) hit the same gap.

What changes

File	Diff	Purpose
crates/perry-hir/src/eval_classifier.rs	+21 / -0	Add KNOWN_CODEGEN_SITE_COUNT + has_known_codegen_sites() so the auto-optimizer can opt into dyn-eval when only bucket-2 sites are present.
crates/perry-hir/src/destructuring/var_decl/alias_tracking.rs	+2 / -1	Add a 'Function' arm to is_global_this_value so globalThis.Function aliases are recognised.
crates/perry-hir/src/lower/expr_new.rs	+9 / -11	function_alias resolution via resolve_class_alias — recognise const F = Function as the global Function constructor.
crates/perry-hir/src/lib.rs	+3 / -2	Re-export has_known_codegen_sites from the crate root.
crates/perry/src/commands/compile/optimized_libs/freshness.rs	+5 / -2	knowngen= key in the auto-opt cache + has_dyn_eval || has_known gate so the dyn-eval interpreter is included in the cache key when the new bucket-2 site detector fires.
CONTEXT-MODE-COMPAT.md	new	Compatibility report — 7 upstream issues found, the 5 patches above, all 11 tools verified end-to-end, and the Perry GC bug investigation that was deferred in favour of the incremental-port approach.
changelog.d/<this-pr>-context-mode-patches.md	new	Per-PR changelog fragment. Filename will be set to the assigned PR number once gh pr create returns.

Verification

context-mode is currently built and shipped at:

• Binary: context-mode 16 MB, optimized release (lto=true, opt-level=3, strip=true)
• Tools (all 11 verified): ctx_index, ctx_search, ctx_execute, ctx_execute_file, ctx_batch_execute, ctx_fetch_and_index, ctx_stats, ctx_doctor, ctx_purge, ctx_upgrade, ctx_insight
• Transport: HTTP on 127.0.0.1:9999 (configurable via CONTEXT_MODE_PORT)
• DB: node:sqlite per-pid FTS5 at /tmp/context-mode-<pid>.db

The 11-tool verified end-to-end trace and the build commands are in CONTEXT-MODE-COMPAT.md.

What is unchanged

• No new perry runtime features; only the HIR + the auto-opt freshness key.
• All 5 patches are surgical — no refactor, no rename, no API break.
• KNOWN_CODEGEN_SITE_COUNT is pub(crate) — no public-API change.
• Upstream CHANGELOG.md is untouched (per perry's freeze policy; fragment goes in changelog.d/).

Scope note

These are local, fork-only patches. The earlier PR PerryTS#7225 against PerryTS/perry was opened by mistake and has been closed. This PR is the corrected target.