lowerAsmExpr stops bailing and builds the inline_asm op: resolves each operand's
effective name (§II.5 — explicit [name] else the {reg} pin), interns
template/constraints/clobbers, lowers input Refs, derives the result TypeId
(0→void, 1→T). Adds the last deferred validation (every %[name] must name an
operand). Multi-output (N>1) bails with a named "Phase E" diagnostic.
emitInlineAsm (backend/llvm/ops.zig) ports Zig's airAssembly: assembles the LLVM
constraint string (outputs → inputs → ~{clobber}, ',' → '|'), rewrites the
template (%[name]→${N}, %%→%, $→$$, %=→${:uid}), then LLVMGetInlineAsm +
LLVMBuildCall2 (AT&T dialect). Dispatch wired in emit_llvm.zig (replacing the C.0
@panic tripwire).
inferType gains an .asm_expr arm (expr_typer.zig) so a bare `x := asm {…-> T}`
binding types correctly — without it the binding inferred .unresolved and
silently produced 0.
llvm_shim.c: LLVMInitializeNativeAsmParser() — the JIT must assemble inline asm
at run time.
Verified end-to-end on the aarch64 host: `mov`/`add` with register-class inputs
and a value output run (exit 42/99), `nop volatile` runs (exit 0). IR is
textbook: `call i64 asm "add ${0},${1},${2}", "=r,r,r"(…)`.
Locked with 1645 (aarch64 add, runs; ir-only on non-aarch64) + 1646 (:= binding).
Updated 1640 (now Phase-E bail) + 1642 (now runs).
zig build test green (654 corpus, 446 unit).
Restructures the .asm_expr lowering arm into lowerAsmExpr, which validates the
asm shape with specific named diagnostics BEFORE the not-yet-implemented codegen
bail, so the user sees the real problem first. Two checklist items enforced:
- template must be a compile-time-known string ("..." or #string), not a
runtime expression;
- an asm with no value outputs must be `volatile` (else its effects could be
deleted) — mirrors Zig's rule.
Valid shapes still bail with the "codegen not yet implemented" message. Result-
type derivation + the operand auto-naming rule stay deferred to Phase C, where a
real IR op makes the result type observable/testable.
Locked with 1641-platform-asm-missing-volatile (the volatile error) and
1642-platform-asm-nop-volatile (no-output + volatile accepted → codegen bail).
zig build test green (650 corpus, 445 unit).
