Commit c030ec1884ad7c553d6680944b47a1fc7653586f | zig

author	Andrew Kelley <andrew@ziglang.org> 2022-06-30 15:58:51-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2022-06-30 18:33:02-07:00
log	c030ec1884ad7c553d6680944b47a1fc7653586f
tree	5e11545a9a732ac2565b403bfd723c5f4f285998
parent	67db2b85b771d8b0f9d765922951c31fce9c8cc2

LLVM: use unnamed struct llvm type for unions when necessary

The constant value lowering for unions was missing a check for whether
the payload was itself an unnamed struct. Lowerings of other types
already handle this case.

closes #11971

1 files changed, 8 insertions(+), 6 deletions(-)

src
- codegen
  - llvm.zig

src/codegen/llvm.zig+8-6

 @@ -3401,6 +3401,13 @@ pub const DeclGen = struct {
                 const union_obj = tv.ty.cast(Type.Payload.Union).?.data;
                 const field_index = union_obj.tag_ty.enumTagFieldIndex(tag_and_val.tag, dg.module).?;
                 assert(union_obj.haveFieldTypes());
+                // Sometimes we must make an unnamed struct because LLVM does
+                // not support bitcasting our payload struct to the true union payload type.
+                // Instead we use an unnamed struct and every reference to the global
+                // must pointer cast to the expected type before accessing the union.
+                var need_unnamed: bool = layout.most_aligned_field != field_index;
                 const field_ty = union_obj.fields.values()[field_index].ty;
                 const payload = p: {
                     if (!field_ty.hasRuntimeBitsIgnoreComptime()) {
 @@ -3408,6 +3415,7 @@ pub const DeclGen = struct {
                         break :p dg.context.intType(8).arrayType(padding_len).getUndef();
                     }
                     const field = try lowerValue(dg, .{ .ty = field_ty, .val = tag_and_val.val });
+                    need_unnamed = need_unnamed or dg.isUnnamedType(field_ty, field);
                     const field_size = field_ty.abiSize(target);
                     if (field_size == layout.payload_size) {
                         break :p field;
 @@ -3419,12 +3427,6 @@ pub const DeclGen = struct {
                     break :p dg.context.constStruct(&fields, fields.len, .True);
                 };
-                // In this case we must make an unnamed struct because LLVM does
-                // not support bitcasting our payload struct to the true union payload type.
-                // Instead we use an unnamed struct and every reference to the global
-                // must pointer cast to the expected type before accessing the union.
-                const need_unnamed = layout.most_aligned_field != field_index;
                 if (layout.tag_size == 0) {
                     const fields: [1]*const llvm.Value = .{payload};
                     if (need_unnamed) {