Introduce the welded comptime `compiler` library (`#library "compiler"` +
`abi(.zig) extern compiler`), per design/comptime-compiler-api.md, and unify
`callconv(...)` into the new `abi(...)` annotation.
abi(...) replaces callconv(...):
- New ABI enum { default, c, zig, pure }; `abi(.c|.zig|.pure)` parses in the
postfix slot before extern/export (and standalone). `kw_callconv` -> `kw_abi`.
- Migrated 52 sx files, the call-convention-mismatch diagnostic, and docs
(readme/specs) from `callconv(.c)` to `abi(.c)`.
Phase 1 — welded compiler library (parse -> registry -> validation -> bridge):
- `abi(.zig) extern compiler` parses on fn decls (carries abi/extern_lib) and
struct decls (StructDecl.abi/extern_lib).
- `#library "compiler"` is the comptime-only internal surface — never dlopen'd.
- src/ir/compiler_lib.zig: the binding registry (the safety boundary). `Field`
welded to StructInfo.Field with layout baked from the real Zig type
(@offsetOf/@sizeOf); `findType`/`findFn`. Welded structs are layout-validated
at registration (field set + total size) as a header checked against the impl.
- Host-call bridge: a `fn abi(.zig) extern compiler` dispatches under the
comptime interp to its registered Zig handler (intern/text_of round-trip),
never dlsym. IR Function.compiler_welded; validated in declareFunction.
- Comptime-only enforcement: a runtime call to a welded fn is a clean
build-gating error (emitCall), not an undefined-symbol link failure.
Phase 2.1 — byte-layout weld foundation:
- Decision: full byte-layout weld (sx struct laid out byte-identically to the
bound Zig type). Registered StructInfo (first non-natural / Zig-reordered
layout). `computeWeldPlan` — pure offset-ordered element plan + padding +
sx-field->LLVM-element remap; unit-tested. Emit/interp wiring is the next
sub-step (2.2+, see current/CHECKPOINT-COMPILER-API.md).
Examples: 0625/0626 (welded struct + fn round-trip), 1183/1184/1185
(layout-mismatch, unexported-fn, runtime-call diagnostics).
Mechanical src/ rename of the linkage-family identifiers whose extern_* target is
collision-free: callForeign→callExtern, marshalForeignArg→marshalExternArg,
dedupeForeignSymbol→dedupeExternSymbol, foreign_name_map→extern_name_map,
is_foreign_c_api→is_extern_c_api. Snapshot-neutral (internal only); suite green
(646 corpus / 444 unit, 0 failed).
Deferred (need per-site analysis — target name already exists): is_foreign↔is_extern
(38 existing), foreign_lib/foreign_name↔extern_lib/extern_name (15/16 existing),
foreign_expr (still built by c_import.zig auto-synthesis). Runtime-class family
(ForeignClassDecl etc. → Runtime*, Decision 5) is Phase 9.2.
Surface rename of the signed integer family: s1..s64 become i1..i64
(u1..u64, usize, isize unchanged). 'string' keeps the s-prefix arm in
name classification; width parsing moves to the i-prefix arm next to
isize.
Internal TypeId tags follow the surface (.s8/.s16/.s32/.s64 ->
.i8/.i16/.i32/.i64), as do mono-key mangle fragments (ptr_i64,
tu_i64_bool) and all display/diagnostic formatting (i{d}).
Migrated in the same sweep: stdlib + examples + issue repros + FFI C
companions (shared symbol names like ffi_id_i64), expected
stdout/stderr/ir snapshots, specs.md, readme.md, CLAUDE.md/AGENTS.md,
implementation_plan.md, docs/, issue writeups. Vendored stb_image and
historical flow state left untouched.
zig build test: 426/426; examples suite: 595/595.
An alloca built at its use site re-executes on every pass through that
block, and LLVM reclaims allocas only at ret — so loop-body locals,
nested-loop index slots, and emitter spill temps (ig.tmp, sret slots, ABI
coercion temps, byval materialization) grew the stack per iteration and
long loops segfaulted on stack exhaustion.
New LLVMEmitter.buildEntryAlloca inserts after existing entry-block
allocas and restores the builder position; every LLVMBuildAlloca site
reachable during instruction emission now routes through it.
Initialization stores stay at the use site (per-iteration re-init is
unchanged), and entry slots become mem2reg-promotable. The 35 .ir
snapshot diffs are pure alloca position moves (type multisets verified
identical per file).
Regression: examples/0047-basic-loop-local-stack-reuse.sx (segfaulted
pre-fix on both the 1M-iteration body-local loop and the 3M-iteration
nested loop).
Move the LLVM type-mapping and C-ABI coercion helpers out of emit_llvm.zig into
the first src/backend/llvm/ modules. Behavior-preserving relocation — the only
rewrites are module plumbing and self.* -> self.e.* facade access.
- src/backend/llvm/types.zig (TypeLowering): toLLVMType + toLLVMTypeInfo.
- src/backend/llvm/abi.zig (AbiLowering): abiCoerceParamType / abiCoerceParamTypeEx
/ needsByval / materializeByvalArg.
- Both are backend *LLVMEmitter facades (field `e`) — the backend analogue of the
IR-side *Lowering facades, NOT a *Lowering facade. They reach the cached LLVM
handles, IR type table, module data layout, builder, and the memoizing
composite-type getters via self.e.*.
- LLVMEmitter stays the facade: toLLVMType (~97 callers) + abiCoerceParamType /
abiCoerceParamTypeEx / needsByval / materializeByvalArg kept as thin wrappers
delegating through new typeLowering()/abiLowering() accessors. Zero caller
churn. toLLVMTypeInfo deleted (sole caller moved).
- Widened getStringStructType / getAnyStructType / getClosureStructType to pub
(the moved toLLVMTypeInfo calls them back; their memoization stays on
LLVMEmitter). verifySizes stays in emit_llvm.zig (size-assertion pass, not type/
ABI lowering). No ABI/type logic, branch order, diagnostic text, or snapshot
changed. Circular import (emit_llvm <-> backend/llvm) resolves via the pointer
facade.
Gate: zig build, zig build test, bash tests/run_examples.sh -> 361/0
(1202 .ir + the 2 ABI unit tests unchanged, no churn).
