[borisbat]

Behavior change: a return inside a try or recover arm is a compile error on every tier (error 30299) - set a variable in the arm and return after the pair. A closure's own return inside the arm stays allowed.

Why. Seven of lookibed's JIT reports: reinterpret<uint8>(true) read 0xff and failed the verifier when it fed a call; a return inside a try arm left the arm and the function answered wrong; a = default<int[4]> zeroed one element; reinterpret<uint>(p) emitted trunc ptr; p - q was a slot call with a run-time stride (0.32 s against 0.0045 s); a global read under a branch in a loop kept its lookup in the loop (0.405 s against 0.042 s); LLVM's optimization remarks had no switch.

What changes.

• A bool-to-integer reinterpret zero-extends and integer-to-bool compares the low byte with zero. The test asserts a bool byte of 2 only under -jit: the interpreter and AOT read such a byte as a C++ bool, which a Debug build reads as its low bit.
• The front end rejects a return inside a try/recover arm; the tests that pinned the interpreter's old return-from-try behavior keep their break and continue cases. AstSerializer::getVersion() moves to 246, so a cached module holding the shape is not served past the new check.
• default<T[N]> zeroes the declared shape when no element is provided.
• A pointer reinterprets to any integer width through ptrtoint.
• i_das_ptr_diff is an intrinsic row: ptrtoint, sub, division by the constant stride.
• jit_get_global_mnh and jit_get_shared_mnh are speculatable, so LLVM hoists a lookup out of a loop.
• --jit-remarks=, --jit-remarks-missed= and --jit-remarks-analysis= print LLVM's remarks and run codegen past both caches.

Observable behavior.

• print("{reinterpret<uint8>(true)}") under -jit: 0xff -> 0x1.
• try { return 1 } recover { }; return 10: the interpreter returned 1 and the JIT 10 with a warning -> compile error on both.
• a = default<int[4]> on [1,2,3,4] under -jit: [0,2,3,4] -> [0,0,0,0].
• reinterpret<uint>(p) under -jit: Invalid bitcast -> the low 32 bits.
• The pointer-difference loop: 0.32 s -> 0.0045 s; the branch-in-loop global read: 0.405 s -> 0.042 s.
• daslang -jit x.das -- --jit-remarks-missed=loop-vectorize prints loop not vectorized: ... per loop.

Where to look. visitExprCast, preVisitExprMakeStruct and preVisitExprReturn in modules/dasLLVM/daslib/llvm_jit.das; the i_das_ptr_diff row in llvm_jit_intrin.das; the extern attributes in llvm_jit_common.das.

Validation, claims, ledger

Validation

• The module-owned suite at the tip: bin/daslang dastest/dastest.das -- --test modules/dasLLVM/tests 170 passed, 5 skipped; tests/jit_tests under -jit 435 passed, 1 skipped.
• Full AOT sweep: preflight --only tests-aot (the test_aot build and sweep over tests/) passed at the tip, 551 s; per-PR CI builds only the subset.
• The three fixed emitter paths were negative-controlled: each test fails with its branch mutated and passes restored.
• Codex review round at the emitter-only tip: no findings, every changed file in its trace. The front-end change came after it: tests/ interpreted 15588 passed, 9 skipped; tests/language under -jit 1981 passed.
• The tree-sitter parser lane runs on ubuntu-24.04: on ubuntu-latest (26.04) the swift toolchain the test action installs cannot load libxml2.so.2, and the lane only runs when a PR touches tree-sitter-daslang/, which the example edit here does.
• The sequence example's smoke clones dasCards main, which returned from inside a try arm; the restructure merged upstream, so the darwin15 lane goes green on a rerun.
• Two docs sub-gates are red on this box for reasons outside the diff: docs/digest (master's shipped digest is stale, the regeneration adds the AstConstVisitor entries an earlier merge introduced) and docs/sphinx-html (the PATH sphinx-build lacks sphinx_sitemap).

Claims - stated, not tested

• A remark without --jit-debug prints its location as <unknown>:0:0; the function name the issue asks for needs a custom diagnostic handler, which needs a C++ callback binding dasLLVM does not expose.

Not done

• JIT: a loop over float? bounded and fed through int? reloads both ints after every float store and never vectorizes - the emitter gives LLVM no alias information for typed pointers (no !tbaa, no noalias on pointer parameters) #4446 typed-pointer alias information: the test lands skipped behind a flag. daslang keeps -fno-strict-aliasing semantics (a pointer is an address), so no type-based alias metadata; noalias where the language can prove it is a separate PR after this arc.
• A lowering of return inside a try arm (a return slot threaded through the arm's captures) is not attempted; the error is the ruling.
• The rename duty for a ManagedVectorAnnotation or ManagedStructureAnnotation name string belongs to the folder that creates the annotation (src/builtin/REVIEW.md and module binding folders); this PR narrows the AST-headers rule and adds no rule there.
• llvm_jit_sanitize.das keeps its own dump_ir: it passes --jit-compile-only and accepts a non-zero exit, which the shared jit_dump does not.

#nightly - the emitter set is pinned and the JIT sweep lanes are nightly.

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🔵 Needs a closer look

Because the changes alter JIT codegen semantics and add LLVM attributes like speculatable whose safety depends on subtle LLVM rules and cross-target runtime invariants, the review evidence calls for domain-expert sanity checks and broader validation before proceeding.

No open issues 🎉

What changed in this PR

This pull request updates dasLLVM’s JIT to fix several correctness edge cases (reinterpret lowering, fixed-array defaults, and return behavior in try/recover arms), improves performance for pointer-difference and global/shared-global lookup patterns, and adds --jit-remarks* flags to surface LLVM optimization remarks. It also adds/updates regression tests and documentation around these behaviors.

Changes:

• Correct JIT lowering for reinterpret (bool↔integer semantics; pointer→integer via ptrtoint) and for default<T[N]> so fixed-size arrays zero the full declared shape.
• Make return inside try/recover arms a hard JIT compile error (while preserving valid closure returns inside arms).
• Add inline lowering for pointer difference (i_das_ptr_diff), enable remark printing via --jit-remarks*, and adjust the JIT pipeline to run past caches when remarks are requested; expand/refactor dasLLVM module tests and fixtures accordingly.

Approval Readiness

This pull request requires changes.

• Moderate: speculatable on jit_get_global_mnh/jit_get_shared_mnh must be safe for speculative execution (no traps). The review notes the call can dereference ctx and may assert on miss; please make the preconditions explicit (e.g., add nonnull on ctx at least) to satisfy the attribute’s contract.
• Moderate: lookups_inside_loop test logic appears potentially fragile because it only exempts .preheader blocks; LLVM can emit other canonical preheader names (e.g. .lr.ph*), which can cause false failures.
• Nits (comment hygiene): multiple top-level multi-line //! doc comments won’t attach to the following def/[test] def and should be converted to // (or moved into the function body / made single-line contracts where appropriate).

File	Summary
tests/​REVIEW.md	Updates test/review guidance for spawned-child execution and cache/output isolation.
tests/​jit_tests/​return_in_try_recover.das	Adds regression coverage asserting JIT rejects return inside try/recover arms (and validates allowed closure-return behavior).
tests/​jit_tests/​reinterpret_ptr_to_uint.das	Adds regression coverage for pointer→integer reinterpret behavior under -jit.
tests/​jit_tests/​default_fixed_array_assign.das	Adds regression coverage ensuring default<T[N]> assignment zeros the entire fixed-size array.
tests/​jit_tests/​bool_reinterpret_byte.das	Adds regression coverage for bool↔integer reinterpret byte/zero-extension semantics under -jit.
tests/​jit_tests/​_fixture_return_in_try_recover.das	Adds a child-run fixture used to reproduce and validate the return-in-try/recover JIT compile error.
modules/​dasLLVM/​tests/​llvm_jit_remarks.das	Adds tests validating --jit-remarks* output and the “run past caches” contract.
modules/​dasLLVM/​tests/​llvm_jit_ptr_diff_inline.das	Adds tests asserting i_das_ptr_diff lowers to inline arithmetic (not an indirect/slot call).
modules/​dasLLVM/​tests/​llvm_jit_pointer_aliasing.das	Adds currently-skipped scaffolding for future typed-pointer aliasing coverage.
modules/​dasLLVM/​tests/​llvm_jit_never_fast_math.das	Refactors tests to use shared IR-dump/helpers infrastructure.
modules/​dasLLVM/​tests/​llvm_jit_global_lookup.das	Extends/refactors tests validating global/shared-global lookup hoisting behavior.
modules/​dasLLVM/​tests/​llvm_jit_debug_info.das	Refactors tests to shared helpers and adjusts debug/symbol expectations.
modules/​dasLLVM/​tests/​_remarks_root.das	Adds a fixture program intended to emit LLVM optimization remarks.
modules/​dasLLVM/​tests/​_ptr_diff_root.das	Adds a fixture program for pointer-difference lowering inspection.
modules/​dasLLVM/​tests/​_pointer_aliasing_root.das	Adds a fixture program for typed-pointer aliasing scenarios (future/placeholder coverage).
modules/​dasLLVM/​tests/​_global_lookup_root.das	Extends fixture to include loop/branch global and shared-global lookup patterns.
modules/​dasLLVM/​tests/​_exe_test_common.das	Introduces/updates shared helpers for JIT execution, IR dumping, and IR parsing in tests.
modules/​dasLLVM/​REVIEW.md	Updates dasLLVM module review/checklist documentation.
modules/​dasLLVM/​daslib/​llvm_jit.das	Implements core JIT lowering fixes (reinterpret behavior, fixed-array default zeroing, and return-in-try/recover refusal).
modules/​dasLLVM/​daslib/​llvm_jit_run.das	Adjusts runtime behavior to ensure remark-enabled runs force recompilation (bypass caches).
modules/​dasLLVM/​daslib/​llvm_jit_plan.das	Tracks remarks enablement and forces codegen to run past caches when requested.
modules/​dasLLVM/​daslib/​llvm_jit_link.das	Routes remark-enabled runs through paths that bypass cached artifacts as intended.
modules/​dasLLVM/​daslib/​llvm_jit_intrin.das	Adds intrinsic mapping/implementation for inline i_das_ptr_diff.
modules/​dasLLVM/​daslib/​llvm_jit_common.das	Wires LLVM pass-remarks options and applies extern attributes (including speculatable) to selected calls.
modules/​dasLLVM/​daslib/​llvm_jit_cli.das	Adds CLI flags: --jit-remarks=, --jit-remarks-missed=, --jit-remarks-analysis=.
modules/​dasLLVM/​CMakeLists.txt	Registers newly added/updated dasLLVM tests in the module build configuration.
modules/​dasLLVM/​ARCHITECTURE.md	Documents the remarks flags and updated JIT behavior/intent (including lookup hoisting behavior).

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🔵 Needs a closer look

This change alters correctness/performance-sensitive LLVM JIT emitter IR/attribute semantics and related CLI/cache behavior in ways that require cross-target human validation beyond the coverage of the added tests and static diff review.

No open issues 🎉

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🟢 Approval recommended

All touched files were reviewed with only minor documentation-style nits noted and no unresolved functional concerns or blocking issues raised in the review evidence.

No open issues 🎉

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🟡 Changes recommended

A moderate active issue remains because the implementation enforces the return-in-try/recover compile error across all compilation modes via the type inference tryDepth > 0 check, which conflicts with the PR description’s claim that it is a -jit-only behavior change and needs either description alignment or mode-specific gating.

1 open issue

• Description says JIT-only, but the check runs in all tiers · New

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🟡 Changes recommended

A documentation nit remains unresolved in ast_serializer.h where the serializer version comment mischaracterizes a behavior change (it’s now a hard compile error for return inside try/recover), which could confuse future cache-version audits.

2 open issues

• Description says JIT-only, but the check runs in all tiers
• Clarify cache version comment for return-in-try rejection · New

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🔵 Needs a closer look

A remaining issue was identified in include/daScript/ast/ast_serializer.h where a version-note comment is misleading about the behavioral change, indicating the documentation needs correction before the change can be considered ready.

2 open issues

• Description says JIT-only, but the check runs in all tiers
• Clarify cache version comment for return-in-try rejection

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🔵 Needs a closer look

The changes span multiple cross-cutting compiler areas (type inference/control-flow semantics, AST cache/serialization versioning, and LLVM JIT codegen/CLI behavior), so correctness and performance require maintainer review and running the full multi-target test/JIT matrix beyond what static diff inspection can verify.

No open issues 🎉

2 resolved since last review

• Description says JIT-only, but the check runs in all tiers
• Clarify cache version comment for return-in-try rejection

_{Review effort: Balanced}

[Copilot]

Note

Copilot was unable to complete this review at the selected tier due to model policy or plan restrictions.

🔵 Needs a closer look

The change affects high-impact core compiler semantics and LLVM JIT/codegen behaviors (including marking runtime helper globals as speculatable), which requires maintainer verification across supported platforms/configurations beyond what static diff review can safely confirm.

No open issues 🎉

_{Review effort: Balanced}