refactor(delib-1b): wasi path-based ops use Linux direct syscalls#48
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refactor(delib-1b): wasi path-based ops use Linux direct syscalls#48
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Second step of the W46 un-link-libc migration. Add `pfdMkdirAt`,
`pfdUnlinkAt`, `pfdRenameAt`, `pfdReadlinkAt`, `pfdDup` to
`src/platform.zig`, each using `std.os.linux.*` direct syscalls on
Linux and `std.c.*` on Mac/BSD. `.windows` arms return -1 so the
helpers compile on Windows; they are never reached at runtime
(every caller already branches to `std.Io.Dir.{createDir,
deleteFile, deleteDir, rename, readLink}` before this point).
Update `src/wasi.zig` callers in:
- path_create_directory (mkdirat)
- path_remove_directory (unlinkat + AT_REMOVEDIR)
- path_unlink_file (unlinkat + 0)
- path_rename (renameat)
- path_readlink (readlinkat)
- fd_renumber (dup)
And inline a `switch (comptime builtin.os.tag)` for
`fd_filestat_set_times`, calling `linux.utimensat(fd, null, ×, 0)`
(equivalent to `futimens(fd, ×)`) on Linux and `std.c.futimens`
elsewhere.
Behavior unchanged: existing `cErrnoToWasi` callers keep working
because the Linux branch mirrors the syscall errno into
`std.c._errno().*` before returning.
Verified:
- `zig build test` (Mac aarch64) — all pass.
- `zig build -Dtarget=x86_64-linux-gnu` — clean.
- `zig build -Dtarget=x86_64-windows-gnu` — clean.
- `bash test/realworld/run_compat.sh` (Mac) — PASS: 50 / FAIL: 0.
2 tasks
chaploud
added a commit
that referenced
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May 9, 2026
Lands `qLoadSpilled` / `qDefSpilled` / `qStoreSpilled` in `src/engine/codegen/arm64/gpr.zig`. Q-form (16-byte) analog of the existing D-form (8-byte) `fp*Spilled` trio. Key properties: - Uses the same `abi.fp_spill_stage_vregs` (V29/V30) staging registers as the D-form fp* helpers — Q view of the same V registers, so no new ABI reservation needed. - Encoders: `inst_neon.encLdrQImm` / `encStrQImm` with SP=31 base register. SP-relative addressing works identically to the D-form path; the only difference is 16-byte stride (Q-form imm12 × 16) vs 8-byte (D-form imm12 × 8). - Alignment check: rejects abs_off > 65520 (= 4095 × 16, the imm12 cap) and abs_off & 0xF != 0 (16-byte alignment). - Graceful spill-overflow surface — diagnostic stderr line matching the existing fp* helpers. Caller-responsibility note: `Allocation.slot(vreg, .fpr)` uses an 8-byte spill-stride formula `(slot_id - max_reg_slots_gpr) * 8`. For 16-byte-aligned v128 spills the caller must lay slots at even-pair indices — slots 14, 16, 18, 20 produce offsets 48, 64, 80, 96 (all 16-byte aligned). Odd slot_ids fail the helper's alignment check. The 9.5-c-ii caller migration (lifting op_simd's SPILL-EXEMPT degradation) handles even-pair discipline at v128 spill-slot allocation. Per ADR-0041 §"Negative" / "Conservative spill-frame size": the conservative per-vreg-pays-its-stride packing means mixed-shape spill frames may have idle bytes; tighter packing defers to Phase 15 alongside the class-aware allocator (ADR-0038). 6 unit tests: - qLoadSpilled in-V-reg (no bytes emitted) - qLoadSpilled spilled (slot 14 → off 48 → LDR Q29, [SP, #48]) - qLoadSpilled rejects 8-byte-aligned-only offset - qDefSpilled in-V-reg returns the V-reg - qDefSpilled spilled returns stage V29/V30 - qStoreSpilled in-V-reg no-op - qStoreSpilled spilled (slot 14, base 16 → STR Q29, [SP, #64]) Mac gates: zone ✓, file_size ✓, spill ✓, lint ✓, test 1205/0/12 (was 1199; +6 q* helper tests). Refs: ADR-0041 §"Decision" / 2 (FP-class register pool reuse with shape-tag axis), ADR-0027 (callee-saved pool) + D-037 (V29/V30 fp_spill_stage_vregs source), `single_slot_dual_ meaning.md` (§14 enforcement preserved — slot id remains the single semantic axis; shape lives on a separate axis).
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Summary
Second step of the W46 un-link-libc migration, building on #47.
pfdMkdirAt,pfdUnlinkAt,pfdRenameAt,pfdReadlinkAt,pfdDuptosrc/platform.zig. Each usesstd.os.linux.*direct syscalls on Linux,std.c.*on Mac/BSD, returns -1 on Windows (never reached — callers already branch tostd.Io.Dirfirst).src/wasi.zigpath-based ops:path_create_directory,path_remove_directory,path_unlink_file,path_rename,path_readlink,fd_renumber.switch (comptime builtin.os.tag)forfd_filestat_set_times— Linux usesutimensat(fd, null, ×, 0)which is equivalent tofutimens(fd, ×).Behavior unchanged: existing
cErrnoToWasicallers still work because the Linux branch mirrors the syscall errno intostd.c._errno().*before returning.Still not ready to flip
link_libc = falseRemaining
std.c.*references that will block un-linking:src/platform.zig:331,352—std.c.getenv(...)(app-cache dir / env lookup)src/trace.zig:71—std.c.write(stderr_fd, ...)(should beplatform.pfdWrite)src/wasi.zig:525—std.c._errno().*incErrnoToWasi(need an alt errno source)src/wasi.zigpath_filestat_set_times already usesstd.c.utimensaton non-Linux (OK for Mac)Those are W46 Phase 1c-1e, intentionally out of scope here.
Test plan
zig build test(Mac aarch64) — all pass.zig build -Dtarget=x86_64-linux-gnu— clean.zig build -Dtarget=x86_64-windows-gnu— clean.bash test/realworld/run_compat.sh(Mac ReleaseSafe) — PASS: 50 / FAIL: 0.Tracks: W46 in
.dev/checklist.md.