User decision: ship B1.2 async with lambda workers (works today, zero
compiler change); defer named-fn workers, which need a new :: callable-
parameter language feature (3 failed worker attempts; partial WIP saved
at .sx-tmp/wip-callable-params/). Records the resolved lambda async idiom
+ resume plan; no compiler/library code changed.
The B1.2 "blockers" were not real:
- Issue 0151 was INVALID: its repro used the non-idiomatic `($A) -> $R`
bare-fn-ptr form. The canonical higher-order pack idiom
`Closure(..$args) -> $R` + `..$args` (see examples/0543-packs-canonical-map)
infers $R fine and runs today with no compiler change. Removed 0151.
- The correct async idiom is verified working live (42 42 for homo + hetero
args): async :: (io, worker: Closure(..$args) -> $R, ..$args) -> Future($R)
with a lambda worker (annotated params) + a `result = ---; result.v = ...`
build form. No compiler change needed.
Issue 0150 (void struct field -> SIGTRAP exit 133) IS a real bug but is only
reached via Future(void) (void-returning worker / timeout) — deferred to B1.4;
B1.2 supports non-void workers.
Updates the PLAN/CHECKPOINT B1.2 status to UNBLOCKED with the corrected idiom
and the resume plan. No compiler/library code changed in this commit.
User correction: async's args are a variadic heterogeneous comptime pack
(..$args: []Type, specs.md:1383), not a single $A. Orthogonal to 0151
(return type-var binding). Recorded for the B1.2 resume.
Stream B1 B1.2 (Io capability + context.io + Future + cancel) is blocked on
two newly-discovered, independent compiler bugs, both with standalone repros:
- 0150: a `void` struct field crashes the compiler with an unsized-type
SIGTRAP in LLVM getTypeSizeInBits. Blocks `Future(void)` -> `timeout`.
- 0151: a type-var inferred from a fn-pointer parameter's RETURN type is not
bound as a usable type in the function body (`unknown type 'R'`). Blocks the
central `async(io, worker: ($A)->$R, arg)` free-fn's `Future(R)`.
The B1.2 design itself is validated end-to-end (the Io protocol threaded on
Context like Allocator, the stateless blocking CBlockingIo default, both
__sx_default_context materializers, and `context.io.now_ms()` all work live).
Only the async/await/timeout ergonomic layer hits the two bugs. Per the
IMPASSABLE STOP rule, all B1.2 working changes were reverted (master green,
726/0) and the work paused pending fixes; WIP is saved at .sx-tmp/b12-wip/.
Checkpoint + plan updated to mark B1.2 BLOCKED with full resume notes.
A fiber needs its own root Context (the spawner's snapshot), not the
ambient one. Probed whether that needs compiler support: it does not.
context is an implicit slot-0 *Context param (call-carried, rides the
callee's own stack) and push Context allocates on the caller frame —
never TLS, never re-read from the __sx_default_context global mid-stack.
So the spawn convention is pure library sx:
snap := context; // snapshot the spawner's context
f := Fiber.{ root = snap }; // store it
push f.root { entry(args) } // trampoline installs it as the fiber root
examples/1804-concurrency-context-snapshot.sx locks it: a trampoline
running under ambient ctx 99 installs a stored snapshot (42); the body
reads 42, and the push scope restores 99 on exit. No fiber runtime yet
(B1.3) — this proves the plumbing it builds on.
The design doc's "lower context as swappable indirection, never raw
TLS" guarded a non-problem — context was already param-carried.
Suite green (726/0).
"pure" universally means side-effect-free (GCC __attribute__((pure)),
FP purity, D's pure) — the opposite of a register-clobbering context
switch. The concept is "naked": no compiler-generated prologue/epilogue,
body is raw asm that emits its own ret. That is the established term
everywhere (LLVM's naked function attribute — which we literally emit —
plus Zig callconv(.naked), Rust #[naked], GCC/Clang __attribute__
((naked))). Rename the keyword + everything keyed off it so concept,
surface, field, and the emitted LLVM attribute all agree.
- ast.zig: ABI enum variant pure -> naked (+ doc).
- parser: accept abi(.naked); error text updated.
- IR Function.is_pure -> is_naked; type_resolver/decl/generic/pack/
emit_llvm references updated; diagnostics say abi(.naked).
- examples 1800-1803 renamed *-pure-* -> *-naked-* (source + expected/
snapshots; .ir/.exit/.stdout/.stderr are byte-identical — the emitted
IR is unchanged, only the keyword spelling differs).
- docs (PLAN-FIBERS, CHECKPOINT-FIBERS, PLAN-POST-METATYPE, the design
roadmap, the compiler-API checkpoint/design) updated; the naming
rationale now records why .naked over .pure.
No semantic change — pure cosmetics. Suite green (725/0).
Adversarial review of B1.0b found a param-bearing abi(.pure) function
emitted invalid LLVM ("cannot use argument of naked function" — loud
verifier error, not silent) because the param-alloca loop spilled the
args to stack slots, which a naked function cannot have.
Fixed forward — this ENABLES the B1.3 context-switch use case rather
than rejecting it: gate the param-alloca loop on fd.abi != .pure in
decl.zig (both body-lowering paths) and generic.zig. A naked function's
args stay in their ABI registers and are read directly by the asm body
(e.g. swap_context reads from/to from x0/x1); the LLVM args are
declared-but-unused, which the verifier allows.
examples/1803-concurrency-pure-asm-param.sx: naked add(a, b) reads x0/x1
(add x0, x0, x1; ret) -> 40 + 2 = 42. aarch64-pinned.
Pack abi(.pure) (variadic + naked — nonsensical, can't read a runtime
pack from registers) left unsupported: pack.zig's param loop is
intertwined with comptime-param/#insert handling, so that case still
hits the loud verifier error. Documented in the checkpoint.
Also updates PLAN-FIBERS / CHECKPOINT-FIBERS for B1.0 completion.
B1.0 complete. Suite green (725/0).
Adversarial review of dd363ca found is_pure was set only at the two
declareFunction decl sites. Generic monomorphization (generic.zig) and
pack expansion (pack.zig) create the IR Function via a different path
and left is_pure false, so a generic abi(.pure) instance bypassed the
emit bail and silently shipped a framed body — it returned 42 but
leaked the prologue's stack adjustment (the exact SP-in != SP-out
corruption the lock exists to prevent).
Both paths now set is_pure and route .pure bodies through the asm-only
+ unreachable cap, mirroring the decl path. Locked by
examples/1801-concurrency-pure-generic-bail.sx (generic .pure reaches
the loud bail).
The review's other CRITICAL (a .pure lambda) is a false positive:
isLambda's return-type scan (parser.zig:3652) breaks on the abi
keyword, so a .pure lambda is unparseable and parseLambda's abi
handling is never reached. Latent isLambda/parseLambda inconsistency,
not a B1 concern.
Suite green (723/0).
First implementation step of Stream B1 (fibers). Make the inert abi(.pure)
ABI carry an is_pure flag through lowering, with LLVM emission deliberately
bailing loudly until B1.0b — the lock half of the lock->green cadence.
- IR Function.is_pure, set from fd.abi == .pure at both declareFunction
decl sites.
- funcWantsImplicitCtx skips .pure (no synthetic __sx_ctx, mirroring the
.c skip): a pure fn reads args from ABI registers, an implicit ctx would
occupy a register slot the asm doesn't expect.
- both body-lowering paths bypass lowerValueBody for .pure: lower the asm
body as statements + cap with unreachable. A pure body has no sx return
(the asm rets itself), so the implicit-return diagnostic must not fire.
- emit_llvm Pass 2 bails loudly when func.is_pure (build-gating nonzero
exit) rather than emit a framed body, whose epilogue would corrupt a
context switch's deliberate SP-in != SP-out.
examples/1800-concurrency-pure-asm.sx: one host example (no .build pin --
the bail fires before instruction selection, so it is host-independent),
locked to the bail snapshot. B1.0b flips emit to LLVM's naked attribute +
asm-only body and pins the example per-arch.
The sx-facing name is "pure" throughout (field, diagnostic); LLVM's naked
attribute is only the B1.0b lowering mechanism. Suite green (722/0).
Carve the async-runtime fibers stream off PLAN-POST-METATYPE Stream B,
mirroring the atomics carve. Grounds the B1 compiler floor against the
tree:
- abi(.pure) exists in the ABI enum but is inert (type_resolver maps it
to .default CC, emit emits no naked attr) -> B1.0 makes it emit LLVM
naked + skip prologue/ctx. Corrected the design's callconv(.naked)
spelling to the real abi(.pure).
- context is already an implicit *Context param (slot 0) + push Context
is a stack alloca -> fiber-local for free; only shared root is the
__sx_default_context global. B1.1 grounded as likely library-only
(probe-first).
- B1.0 snapshot story corrected: naked body is raw per-arch asm -> two
arch-gated examples (aarch64 + x86_64), not one host .ir.
Full xfail->green step detail + a B1.0a kickoff prompt. Baseline green
(721/0). No code change; first implementation step is B1.0a.
Final whole-stream adversarial review came back CLEAN (no CRITICAL/MEDIUM/LOW).
Close the one informational gap it noted: extend examples/1703 with a #run
comptime swap so swap's comptime VM arm is locked (742, matches runtime) — every
op now has comptime↔runtime corpus coverage.
Docs: PLAN-ATOMICS.md status banner (COMPLETE); PLAN-POST-METATYPE.md Stream A
marked done (unblocks B2-channels + C-parallel); readme.md gains a user-facing
Atomics section. Suite green (721/0).
emitAtomicRmw xchg arm (swap) and emitAtomicFence (LLVMBuildFence) now real.
examples/1703 (swap old=7/now=42, 'atomicrmw xchg') + 1704 (fence release/acquire/
seq_cst) green. Unit test 'emit: atomic swap (xchg) + fence'. Stream A
(atomics) is feature-complete: load/store, RMW (add/sub/and/or/xor/min/max),
compare_exchange[_weak], swap, fence. Suite green (721/0).
emitAtomicCmpxchg: LLVMBuildAtomicCmpXchg (success/failure orderings,
singleThread=0) returns a {T, i1} pair; LLVMSetWeak for the weak variant. The
sx ?T result (null = SUCCESS) is built as { extractvalue 0 (actual value),
xor(extractvalue 1 (success), true) } -- has_value = NOT success. Integer-only
(recognizer guard), so never a pointer/niche optional.
examples/1702 green: successful CAS returns null (value updated), failing CAS
returns the actual value (unchanged), weak retry loop increments a counter
(100 -> 105). LLVM IR shows `cmpxchg ... acq_rel acquire` and `cmpxchg weak`.
Unit test `emit: atomic cmpxchg (strong + weak)` locks `cmpxchg` + the weak
marker. Suite green (718/0).
compare_exchange/_weak wired end-to-end except LLVM emission (bails loudly;
A.2b makes it real). New IR op atomic_cmpxchg + AtomicCmpxchg{ptr, cmp, new,
val_ty, success_ordering, failure_ordering, weak}; result type = ?T (null =
SUCCESS, failure carries the actual value for retry). print arm; emit dispatch
-> emitAtomicCmpxchg (BAILS). comptime_vm arm does real single-thread CAS (read
actual / compare / store-on-equal / build ?T: success->none, failure->some;
weak == strong at comptime). Recognizer extended (atomic_cmpxchg/_weak, 6 args)
-- CAS restricted to INTEGER T (loud reject); BOTH orderings resolved via
atomicOrderingFromNode; dual-ordering validation (failure may not be
release/acq_rel nor stronger than success, via atomicOrderingRank). Methods
compare_exchange/_weak on Atomic($T) with comptime $success/$failure: Ordering.
examples/1702 locked to the bail; examples/1186 locks a rejected ordering pair.
Suite green (718/0).
emitAtomicRmw: LLVMBuildAtomicRMW (binop from RmwKind; signed Min/Max vs
unsigned UMin/UMax from val_ty; singleThread=0; LLVM supplies ABI alignment).
examples/1701 green (add/sub/and/or/xor/min/max return old values, results
verified). Unit test 'emit: atomic rmw (add + signed/unsigned min)' locks
'atomicrmw add' + signed 'min' vs unsigned 'umin'. Suite green (716/0).
Migrate Atomic methods from seq_cst-only to the explicit ordering surface now
that comptime value params work on generic-struct methods (workers 3c4305f /
d7a6857 / d95ba0a):
- atomic.sx: load/store take a comptime $o: Ordering (explicit, Rust-style; no
default, matching design 4.6). a.load(.acquire) -> 'load atomic .. acquire'.
- call.zig: atomicOrderingFromNode resolves a comptime-bound ordering identifier
via comptimeIntNamed (+ atomicOrderingFromTag); documents the sx-Ordering <->
IR-AtomicOrdering declaration-order invariant. The per-op validity guard fires
through the method path (a.load(.release) is a compile error).
- 1700 migrated to explicit orderings (output unchanged 7/42/43).
Suite green (715/0).
Adversarial review of A.0 found two silent-wrong defects reachable via the public
atomic_load/atomic_store intrinsics (raw LLVM verifier errors, not clean sx
diagnostics) + a latent alignment fallback. All fixed:
- scalar-kind allowlist (call.zig): the size-only T guard admitted same-sized
aggregates ([8]u8, 8-byte structs) -> invalid 'load atomic [8 x i8]'. Now an
allowlist switch (integer/float/bool/pointer/enum/vector) rejects loudly.
- per-op ordering validity (call.zig): load cannot release/acq_rel, store cannot
acquire/acq_rel -> loud diagnostic instead of invalid LLVM.
- val_ty align fallback (ops.zig): the 'else .i64' (align 8) default would
over-align a sub-8 store -> now bails loudly on a missing val_ty.
Locked by examples 1130 (non-scalar) + 1131 (bad ordering). Suite green (713/0).
Replace the A.0a emit bail with real LLVM atomic codegen:
- emitAtomicLoad: LLVMBuildLoad2 + LLVMSetOrdering + LLVMSetAlignment
- emitAtomicStore: LLVMBuildStore + LLVMSetOrdering + LLVMSetAlignment (value
coerced to the pointee type, mirroring emitStore)
- llvmOrdering: explicit sx AtomicOrdering -> LLVMAtomicOrdering map (LLVM's enum
is non-contiguous; never an identity cast)
examples/1700 now prints 7/42/43; IR is 'load atomic i64, ptr .. seq_cst, align 8'
+ 'store atomic ..'. Unit test 'emit: atomic load/store (seq_cst, aligned)' locks
the emission shape (load atomic/store atomic/seq_cst/align 8) without a fragile
full-module .ir snapshot. Suite green (710 examples + units).
Stream A (atomics) foundation. Net-new atomic load/store codegen path, wired
end-to-end except LLVM emission, which deliberately bails loudly so the example
locks to a clean diagnostic (A.0b turns it green — cadence: no commit both adds a
test and makes it pass).
- library/modules/std/atomic.sx: Ordering enum, Atomic($T) transparent wrapper
(init/load/store, seq_cst-only for now), atomic_load/atomic_store #builtin
intrinsics. Opt-in import, NOT in the universal std facade (Ordering in the
prelude grows every program's type table + churns 37 .ir snapshots).
- IR: atomic_load/atomic_store ops + AtomicOrdering (all 5) + structs (inst.zig);
print arms; comptime_vm arms reuse load/store (single-thread correct);
recognizer tryLowerAtomicIntrinsic (const-ordering + scalar-size guards, both
loud); emit dispatch -> emitAtomicLoad/Store bail via comptime_failed.
- examples/1700-atomics-load-store.sx locked to the bail diagnostic.
Full ordering surface (a.load(.acquire)) blocked on comptime-constant ordering
propagation (comptime enum value params) — A.0.5, migrated not legacy.
Fold the adversarial-review corrections into the program plan + design-of-record:
- atomics is 100% net-new (no scaffolding; lower.zig 'ordering' is comparison-only)
- context is already an implicit *Context param (not TLS) — B1.1 rescoped
- abi(.pure) exists but is inert (no naked emission) — B1.0 rescoped
- B1.3 switch-stress harness is the first deliverable + mandatory stack guards
- Stream C gated on a named TSan/ASan + run-N stress harness, not a footnote
Update CHECKPOINT-COMPILER-API: Resume banner + Log entries for Step D
(metatype declare/define re-expressed as sx over the compiler-API) and the
empty-member-types-valid change. 709/0 corpus + 476/476 unit.
The legacy tagged-Value Interpreter is gone. Relocate the Value result-DTO
+ decodeVariantElements into a new comptime_value.zig (the VM<->host
materialization boundary); repoint comptime_vm/emit_llvm/ir-barrel Value to
it and BuildConfig to compiler_hooks; delete the dead valueToReg bridge;
slim compiler_lib.zig to just the name registry (BoundFn{sx_name} + bound_fns
+ findFn — weldedCompilerFn only validates names); simplify printInterpBailDiag
to comptime_vm.last_bail_reason; drop the unused interp_mod import in lower.zig.
rm src/ir/interp.zig + interp.test.zig.
Value is relocated (not eliminated): it survives only as the slim result DTO
at the VM->valueToLLVMConst boundary; the execution-time marshaling the VM
pivot targeted is gone. Drop dead Value.asString/reflectTypeId.
706/0 corpus + 476/476 unit.
The #compiler struct attribute + #compiler-suffixed bodyless methods were
fully superseded by abi(.compiler) (P5.5) — no sx code uses them.
Remove the hash_compiler token (token/lexer/lsp), the is_compiler_struct /
struct_default_compiler parser machinery + the two compiler_expr body-
synthesis branches, the compiler_expr AST variant, and every
.builtin_expr/.compiler_expr switch arm + == .compiler_expr check across
sema/resolver/semantic_diagnostics/generic/decl/call/calls (kept .builtin_expr).
abi(.compiler) is untouched. Delete the obsolete calls.test.zig dispatch test.
500/500 unit + 706/0 corpus.
Remove the comptime_flat/need_vm gate and the vm_result-orelse-legacy
fallback from emit_llvm.zig (runComptimeSideEffects + emitGlobals const-init)
and comptime.zig (runComptimeTypeFunc). The comptime VM now always runs;
a bail is always a build-gating diagnostic, never a fallback. Delete the
now-moot entryNeedsVm. runComptimeSideEffects drops the Interpreter entirely
(VM writes #run output direct to fd 1); emitGlobals keeps a fresh interp_inst
only as the valueToLLVMConst materialization context (the regToValue bridge,
removed with interp.zig in a later step).
#insert (evalComptimeString) still routes through the legacy interp — deferred
until interp.zig deletion.
Reconcile 1654: the comptime asm-global #run now reports the VM's clean dlsym
bail instead of the legacy CannotEvalComptime wrapper (exit still 1).
501/501 unit + 706/0 corpus.
`comptime_vm` exec now handles `bit_and`/`bit_or`/`bit_xor`/`bit_not`/`shl`/`shr`
(a new `bitwise` helper next to `arith`), mirroring the legacy interp's i64 model
exactly: the shift amount clamps to `@min(rhs, 63)` and `shr` is an arithmetic
right shift (sign-extending).
These were unported and bailed; the `shr` gap surfaced via the iOS-device bundler
once P5.5 let it run further (1616). With the port, 1616's strict VM run reaches
the real bundler logic and stops only at the genuinely-unavailable iOS runtime on
macOS (`_UIApplicationMain` / no linked binary under `sx run`), as expected.
New corpus test `examples/0639-comptime-bitwise-shift.sx` folds AND/OR/XOR/NOT/
shl/shr/arith-shr as `::` consts — identical on both evaluators. 704/0 both gates.
`BuildOptions :: struct #compiler { ...35 methods... }` becomes
`BuildOptions :: struct { }` (an opaque null-sentinel handle) plus 35 free
`ufcs (self: BuildOptions, …) abi(.compiler)` decls in build.sx, each serviced
by a new `comptime_vm.callBuildOptionFn` arm (off `callCompilerFn`). No legacy
`compiler_lib` handler: the names are registered in `bound_fns` with a single
bailing stub only so `weldedCompilerFn` accepts them.
- String lifetime: setters dupe the arg into the persistent `Vm.gpa` (the
Compilation allocator, threaded into both `tryEval` and `runBuildCallback` —
not the per-eval VM arena) and write/append to the threaded `BuildConfig`.
Getters read the field/slice or compute the target predicate from the triple.
- Dispatch routing (Option B): a `#run`/const-init entry that directly calls a
compiler-domain/welded fn (`emit_llvm.entryNeedsVm`) runs on the VM with no
legacy fallback regardless of the `-Dcomptime-flat` gate, so gate-OFF stays
green without a legacy BuildOptions handler (P5.7 retires the legacy interp).
- Mark the 5 `platform/bundle.sx` getter-calling helpers `abi(.compiler)` (they
are comptime-only bundler code; otherwise their now-welded getter calls trip
the runtime-call gate).
- 37 `.ir` snapshots regenerated (std transitively imports build.sx → string-
pool/type-table indices shift); verified `.ir`-only, zero behavior-stream diffs.
BuildOptions `compiler_call` strict bails gone (1609/1614/1615 strict-clean);
1616 now bails on a separate, pre-existing unported bitwise/shift VM gap (`shr`),
to port first in P5.6. 703/0 both gates.
Also sweep the outdated "flat memory" terminology to "comptime/byte-addressable"
across comptime_vm + the plan/checkpoint/CLAUDE docs: the comptime VM is
arena-backed, byte-addressable memory where `Addr` is a real host pointer, not a
flat contiguous address space (flag names `-Dcomptime-flat`/`SX_COMPTIME_FLAT` kept).
Records the user's decision: drop gate-OFF entirely (VM is the sole comptime
evaluator; delete interp.zig); migrate BuildOptions directly to VM-native
abi(.compiler) arms with NO legacy handlers; ALL bundling + code signing for
every target (macOS/iOS-device/iOS-sim/Android) lives in the sx default_pipeline;
validate against ~/projects/m3te + ~/projects/distribution. Phase 5 steps
P5.5-P5.8 in PLAN-COMPILER-VM.md.
Per user direction: the low-level abi(.compiler) primitive surface is the
comptime 'compiler' library, so name the file compiler.sx (a peer of build.sx)
instead of the interim std/build.sx — which also frees the 'build' name for the
default build IMPLEMENTATION (default_build + on_build slot), which will live in
modules/build.sx alongside the BuildOptions DSL.
Updated the two example imports + the plan's Phase 5 file-split note. 704/0
both gates.
The one genuine action primitive: link(objects, output, libraries, frameworks,
flags, target) in library/modules/std/build.sx. Per the user decision to drop
fallibility from the build callback, link is plain VOID — a link failure bails
on the VM (hard build error), no -> ! / failable-tuple needed.
comptime_vm.zig can't depend on the driver (core/main/target), so link
dispatches through a new compiler_hooks.BuildHooks { ctx, link } vtable that
main.zig installs into BuildConfig.build_hooks before the post-link callback.
The driver side is main.LinkHooksCtx (unions explicit + CLI link flags, calls
target.link). New VM readers readStringList / readStringArg (inverse of
makeStringList) decode the List(string)/string args from flat memory.
Smoke test examples/1663-platform-build-pipeline-link (AOT): a post-link
callback re-links the build's own objects (c_object_paths + emit_object) into a
temp output via sx link — the relinked binary is a functional executable that
runs. Negative-probe verified (bad path -> ld fails -> ComptimeVmBail -> build
exit 1). The Zig driver still auto-links; removing that is P5.4.
704/0 both gates.
The compiler emits the sx object eagerly (the Zig driver, before the post-link
callback), so emit_object is a QUERY (not an action): it returns the path from
a new BuildConfig.object_path field main.zig forwards — no driver vtable. This
completes the build-pipeline QUERY primitives (emit_object / c_object_paths /
link_libraries); only link (the genuine action) remains for the vtable step.
Extended examples/1662 to also assert emit_object().len > 0. 703/0 both gates.
Two abi(.compiler) build-pipeline primitives the sx driver will pass to link:
- c_object_paths() -> List(string) (#import c companion objects)
- link_libraries() -> List(string) (#library names)
They live in a new stdlib home library/modules/std/build.sx and are serviced
by comptime_vm.callCompilerFn reading two new BuildConfig fields that main.zig
forwards before the post-link callback. New reusable VM helper makeStringList
builds a List(string) in flat memory from the call's result type offsets
(target-aware); invoke/callCompilerFn now thread ins.ty for that. Legacy
handlers bail loudly (VM-only by nature — post-link; List(string) isn't
faithfully buildable in the legacy Value model, 0141).
Smoke test examples/1662-platform-build-pipeline-queries (AOT + a 1-line C
#source → one object): a post-link callback verifies the VM-built list is
well-formed; build exit 0 only if so (negative-probe confirmed a real guard).
emit_object + link (the actions) deferred to P5.2b — they replace the Zig
driver's auto-emit/auto-link and need a host-installed callback vtable.
703/0 both gates.
core.invokeByFuncId routes the post-link callback through comptime_vm.tryEval
instead of the legacy Interpreter. REQUIRED because the sx build driver
allocates/grows Lists, which the legacy interp can't do at comptime (issue
0141: struct_get: base has no fields); the VM can. No fallback (a
side-effecting post-link callback can't double-execute): a VM bail is a hard
build error (comptime_vm.last_bail_reason, surfaced by printInterpBailDiag).
BuildConfig + import_sources threaded in; non-empty args rejected loudly.
flushInterpOutput deleted (VM out writes direct via host-FFI).
Smoke test examples/1661-platform-post-link-vm-list (AOT): a post-link
callback grows a List to 3 + returns len==3, so the build succeeds (exit 0)
only via the VM. First corpus coverage of the post-link path.
702/0 both gates.
Lands the full VM/compiler-API arc on branch reify (701/0 both gates):
- abi(.compiler) ABI replaces abi(.zig) extern compiler + the fake
#library "compiler"; bodiless decl = compiler-API surface, bodied =
user compiler-domain fn (lowered for VM eval, emit-skipped).
- out is a plain sx fn (libc write) — the out builtin deleted; the VM
handles it via host-FFI. trace_resolve + interp_print_frames ported.
- 4B VM-native diagnostics: 1179/1180 render proper comptime type
construction failed: under strict.
- S5a: build_options/set_post_link_callback on abi(.compiler) with
BuildConfig threaded into the VM (green intermediate).
- 0522 fixed (describe(args: []Type)); regression 0638.
Strict deletion-gate down to 4 compiler_call bails (1609/1614/1615/1616)
+ 1654 (legitimate unresolvable-symbol diagnostic).
0143: a ..$args pack forwarded as a []Type argument across a call is backed by a
[N x Any] (16B) array but viewed as []type_value (8B) -> half-stride reads. A
lowering bug the legacy Value model masks; the byte-accurate VM exposes it. Blocks
examples/0114 on the VM. Filed per CLAUDE.md (not worked around; the type_name
.unresolved guard only makes the VM decline rather than emit garbage).
Checkpoint also records the sequencing insight: comptime `out` (print) can only
land once the fallback is removed (a print-then-bail double-prints under the legacy
re-run), so side-effecting ops + fallback-removal are the FINAL step; pure ops +
migrations land first.
Add -Dcomptime-flat-strict / env SX_COMPTIME_FLAT_STRICT (implies comptime_flat):
at all three comptime sites (type-fn in lower/comptime.zig, const-init + #run in
emit_llvm.zig) a VM bail becomes a build-gating error naming the reason INSTEAD of
falling back to legacy. Forces every comptime eval onto the VM so the complete gap
set is enumerable in one sweep; when the corpus is green under strict mode AND every
example matches legacy, interp.zig can be deleted.
Default behaviour unchanged (699/0 both default gates). Fixed a wiring bug: the
type-fn site's local comptime_flat didn't include the strict flag (every type-fn
falsely reported <unknown>); strict now implies flat there too.
Swept the gap list (19 strict bails): switch_br (5, + unmasks a []Type-across-call
silent-wrong in 0114), compiler_call (6, = the BuildOptions->abi(.zig) extern
compiler migration), out (2), type_name (1), global_addr (1), interp_print_frames
(1), 2 negative-test diagnostics (1179/1180), 1 dlsym (1654). Recorded as the
deletion checklist in CHECKPOINT-COMPILER-API.md.
Direction correction (user): the VM does NOT get a transitional compiler_call →
hook-registry shim. BuildOptions is re-expressed as abi(.zig) extern compiler
functions (the compiler-API the VM already dispatches via callCompilerFn), and the
#compiler attribute + compiler_call op + Value-based hook Registry are deleted.
Also record that 4D (host FFI) is DONE via the arena/absolute-pointer allocator
(the earlier pin/tag hazard is moot — the arena never moves an allocation), and
that 0602/0603 stay on legacy fallback until the BuildOptions migration lands.
No code change (reverted the speculative compiler_call bridge).
Update the resume banner: box_any/unbox_any (4A.1), arena allocator with absolute
host-pointer Addr (4D.0), general host-FFI escape (4D.1), slice/string args + float
guards (4D.2) all landed and green (699/0 both gates). Next is 4D.3 (#compiler
hooks / compiler_call) with the hook-ABI + build_config findings recorded for a fast
restart.
Extract marshalExternArg: a scalar/pointer word passes verbatim (a cstring arg
already works as a pointer word via 4D.1); a string/slice {ptr,len} fat pointer is
copied into a NUL-terminated arena buffer and its char* passed -- mirrors the legacy
marshalExternArg, and is what the bundler's popen(cmd: [:0]u8, ...) needs.
Add float guards on args AND returns: floats are kindOf == .word but the host_ffi
trampolines have no float variant, so bail loudly rather than miscall through an
integer register (the legacy interp doesn't support float FFI either -> parity).
New example 0637-comptime-extern-slice-arg (#run strlen("hello, world") with a
[:0]u8 param -> 12) runs HANDLED on the VM, byte-matching legacy. 699/0 both gates.
The FFI escape now covers scalar/pointer/cstring/slice args + scalar/pointer returns.
Replace the "extern not ported -> bail" stub in Vm.invoke with callHostExtern:
resolve the symbol via host_ffi.lookupSymbol (dlsym RTLD_DEFAULT) and dispatch
through the host_ffi trampolines, like the legacy interp.callExtern.
Marshalling is trivial now that Addr is a real host pointer (4D.0): every WORD-kind
arg passes as usize verbatim (a scalar's bits OR a pointer, no translation), and a
pointer return is a valid Addr. Picks callPtrRet (void*-ABI) for pointer-ish
returns, callIntRet (i64-ABI) otherwise; honors variadic. Non-word
(aggregate/string/float) args+returns bail loudly (4D.2 adds them). One general
mechanism for all externs, not per-builtin special cases.
New example 0636-comptime-extern-libc (#run toupper(97)/tolower(90) -> 65/122) runs
HANDLED on the VM, output byte-matching legacy. 698/0 both gates.
Replace the growable ArrayList(u8) flat buffer (reallocs/MOVES on growth) with a
std.heap.ArenaAllocator. Each allocBytes is a separate arena allocation that never
moves and is freed wholesale on deinit -- no per-object free, no cap, no fixed
buffer. Addr is now the allocation's ABSOLUTE host pointer (@intFromPtr), not an
offset, so a flat-memory pointer and an FFI-returned host pointer are the same kind
of value -- the FFI bridge (4D.1) passes them to/from libc with zero translation and
no per-call pinning (the moving-buffer hazard is gone by construction).
readWord/writeWord/bytes deref the absolute pointer with a null-check bail (the
malformed-IR / null-deref safety contract). Dropped the offset-based upper-bounds
check (can't bound an absolute pointer; Frame.bad_ref still catches the dominant
malformed-IR vector) and the test-only mark/reset (arena has no reset-to-mark; the
VM never used them outside tests).
697/0 both gates + all unit tests (rewrote the two Machine tests). Pure refactor, no
comptime behavior change.
Ported the Any-boxing conversion pair:
- box_any: alloc the 16-byte { type_tag@0, value@8 } box, tag = source TypeId
index (matches the legacy comptime interp; runtime anyTag also normalizes
arbitrary-width ints). Value slot holds a word source's scalar bytes (via
writeField(source_type) so f32 round-trips) or an aggregate source's
flat-memory ADDR (the runtime pointer-in-value-slot shape).
- unbox_any: read the value slot back (word -> readField; aggregate -> the
stored ADDR).
Required promoting .any to a first-class flat-memory aggregate (was
kindOf -> .unsupported): kindOf(.any) = .aggregate (16B, by-address) and
fieldOffset special-cases .any to the {@0, @8} layout (shared with
string/slice). Without the latter a struct_get on an Any panicked
(union field 'struct' while 'any' is active) -- caught + fixed, no crash.
Updated two unit tests that used unbox_any as the "unported op" example ->
compiler_call; added a box->unbox round-trip test. 697/0 both gates + all
unit tests. The 6 box_any examples no longer bail at box_any (output matches
legacy) but fall back further at switch_br/type_name/out (later 4A steps).
Audited the 5 roles interp.zig still serves (A comptime folds, B #insert,
C post-link bundler, D #compiler hooks, E bail diagnostics) and the shared
substrate (Value tagged union + host_ffi bridge).
User decision: UNIFY — the VM gains a host-FFI escape + real-pointer
translation and runs the post-link bundler too; interp.zig fully deleted.
Dependency-ordered sub-phases recorded in PLAN-COMPILER-VM.md:
4A finish comptime ops (box_any/unbox_any, out/print, global_addr, trace) ->
4B VM-native diagnostics -> 4C #insert -> 4D host FFI + #compiler hooks ->
4E post-link bundler (+ dedicated bundle tests) -> 4F flip default + delete
interp.zig/Value + re-express define/make_enum over the compiler-API.
No code change — planning + checkpoint only.
