lab/sx
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fix: allow void (zero-sized) struct/tuple fields instead of crashing (issue 0150)

Browse Source 
A struct/tuple/?T with a void field crashed the compiler: the field lowered to
LLVM's unsized 'void' type, which traps getTypeSizeInBits. Lower a void field to
a SIZED zero-byte [0 x i8] (fieldLLVMType) so the enclosing aggregate stays sized
with identical element indices, and skip inserting a value for a void field in
emitStructInit (the i64 placeholder would type-mismatch the [0 x i8] slot and
corrupt the aggregate constant -> runtime bus error). Future(void) now works.

Regression: examples/0190-types-void-struct-field-zero-sized.sx
This commit is contained in:
agra
2026-06-21 09:21:18 +03:00
parent 7057175fb6
commit 4fc5411cd9
8 changed files with 75 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/llvm/ops.zig
View File

@@ -1720,6 +1720,18 @@ pub const Ops = struct {
const elem_llvm_ty = if (is_array) c.LLVMGetElementType(struct_ty) else null;
var result = c.LLVMGetUndef(struct_ty);
for (agg.fields, 0..) |field_ref, i| {
// A `void` (zero-sized) struct/tuple field lowers to a zero-width
// `[0 x i8]` slot (see `TypeLowering.fieldLLVMType`); it carries no
// data. Skip inserting a value — the field's lowered ref is an i64
// placeholder (`emitConstInt`'s void path) whose type mismatches the
// slot and would corrupt the aggregate. The undef `[0 x i8]` element
// is already the correct zero-width value.
const field_is_void = switch (self.e.ir_mod.types.get(instruction.ty)) {
.@"struct" => |s| i < s.fields.len and s.fields[i].ty == .void,
.tuple => |t| i < t.fields.len and t.fields[i] == .void,
else => false,
};
if (field_is_void) continue;
var field_val = self.e.resolveRef(field_ref);
if (is_vector) {
// Coerce element to match vector element type