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fix(ffi): replace silent .void arg-type fallback with loud .unresolved (issue 0074)

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Four FFI call-arg lowering sites resolved an argument's IR type via
`getRefIRType(arg_ref) orelse .void` — a silent fallback to the load-bearing
real type `.void`. A failed lookup there is a codegen invariant violation, but
`.void` is treated by downstream `toLLVMType` → `abiCoerceParamType` →
`coerceArg` as a legitimate void-typed foreign argument, corrupting the call
ABI with no diagnostic.

Add one shared resolver `LLVMEmitter.argIRTypeOrFail` that returns the
dedicated `.unresolved` sentinel on a failed lookup — never `.void`/`.s64` — so
the failure cannot masquerade as a real type and trips `toLLVMType`'s existing
hard `@panic` tripwire at the call site. Route all four sites through it:
  - src/ir/emit_llvm.zig          JNI constructor (NewObject) arg loop
  - src/backend/llvm/ops.zig      objc_msgSend arg loop
  - src/backend/llvm/ops.zig      JNI non-virtual call arg loop
  - src/backend/llvm/ops.zig      JNI Call<Type>Method arg loop

Happy path is byte-identical (every real arg already has a resolved type); FFI
examples stay green with zero snapshot churn.

Regression test (fail-before/pass-after) in src/ir/emit_llvm.test.zig asserts an
unresolvable FFI arg ref now yields `.unresolved`, not the old silent `.void`.
This commit is contained in:
agra
2026-06-03 15:43:27 +03:00
parent 6f4b872254
commit 4537538bb2
4 changed files with 145 additions and 4 deletions
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6
src/backend/llvm/ops.zig
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@@ -514,7 +514,7 @@ pub const Ops = struct {
// coercion applied so structs / strings decay the
// same way they do for any C foreign call.
for (msg.args, 0..) |arg_ref, i| {
const raw_ty = self.e.getRefIRType(arg_ref) orelse .void;
const raw_ty = self.e.argIRTypeOrFail(arg_ref);
const raw_llvm = self.e.toLLVMType(raw_ty);
const coerced_ty = self.e.abiCoerceParamType(raw_ty, raw_llvm);
param_types[i + 2 + sret_off] = coerced_ty;
@@ -728,7 +728,7 @@ pub const Ops = struct {
call_args_nv[2] = cls;
call_args_nv[3] = mid_val;
for (msg.args, 0..) |arg_ref, i| {
const raw_ty = self.e.getRefIRType(arg_ref) orelse .void;
const raw_ty = self.e.argIRTypeOrFail(arg_ref);
const raw_llvm = self.e.toLLVMType(raw_ty);
const coerced_ty = self.e.abiCoerceParamType(raw_ty, raw_llvm);
call_param_types_nv[i + 4] = coerced_ty;
@@ -758,7 +758,7 @@ pub const Ops = struct {
call_args[1] = target;
call_args[2] = mid;
for (msg.args, 0..) |arg_ref, i| {
const raw_ty = self.e.getRefIRType(arg_ref) orelse .void;
const raw_ty = self.e.argIRTypeOrFail(arg_ref);
const raw_llvm = self.e.toLLVMType(raw_ty);
const coerced_ty = self.e.abiCoerceParamType(raw_ty, raw_llvm);
call_param_types[i + 3] = coerced_ty;