| author |  Jacob Young <jacobly@ziglang.org> 2025-06-09 02:34:30-04:00 |
| committer |  Matthew Lugg <mlugg@mlugg.co.uk> 2025-06-12 17:51:30+01:00 |
| log | 746137034e244d863a022b821ae0a1952d9d93c1 |
| tree | 62ad6883d960d3f995202eb4901aecddbf0fb957 |
| parent | d312dfc1f21a9194dd06c1d45f653bdaf823d2f6 |
| signature |  Commit is signed but in an unrecognized format. |
Sema: fix union layout logic to match struct layout logic
2 files changed, 26 insertions(+), 17 deletions(-)
src/Sema.zig+9-1
| ... | ... | @@ -35054,7 +35054,7 @@ pub fn resolveUnionAlignment( |
| 35054 | 35054 | union_type.setAlignment(ip, max_align); |
| 35055 | 35055 | } |
| 35056 | 35056 | |
| 35057 | /// This logic must be kept in sync with `Zcu.getUnionLayout`. | |
| 35057 | /// This logic must be kept in sync with `Type.getUnionLayout`. | |
| 35058 | 35058 | pub fn resolveUnionLayout(sema: *Sema, ty: Type) SemaError!void { |
| 35059 | 35059 | const pt = sema.pt; |
| 35060 | 35060 | const ip = &pt.zcu.intern_pool; |
| ... | ... | @@ -35090,6 +35090,14 @@ pub fn resolveUnionLayout(sema: *Sema, ty: Type) SemaError!void { |
| 35090 | 35090 | const field_ty: Type = .fromInterned(union_type.field_types.get(ip)[field_index]); |
| 35091 | 35091 | if (field_ty.isNoReturn(pt.zcu)) continue; |
| 35092 | 35092 | |
| 35093 | // We need to call `hasRuntimeBits` before calling `abiSize` to prevent reachable `unreachable`s, | |
| 35094 | // but `hasRuntimeBits` only resolves field types and so may infinite recurse on a layout wip type, | |
| 35095 | // so we must resolve the layout manually first, instead of waiting for `abiSize` to do it for us. | |
| 35096 | // This is arguably just hacking around bugs in both `abiSize` for not allowing arbitrary types to | |
| 35097 | // be queried, enabling failures to be handled with the emission of a compile error, and also in | |
| 35098 | // `hasRuntimeBits` for ever being able to infinite recurse in the first place. | |
| 35099 | try field_ty.resolveLayout(pt); | |
| 35100 | ||
| 35093 | 35101 | if (try field_ty.hasRuntimeBitsSema(pt)) { |
| 35094 | 35102 | max_size = @max(max_size, field_ty.abiSizeSema(pt) catch |err| switch (err) { |
| 35095 | 35103 | error.AnalysisFail => { |
src/Type.zig+17-16
| ... | ... | @@ -3915,29 +3915,30 @@ fn resolveUnionInner( |
| 3915 | 3915 | pub fn getUnionLayout(loaded_union: InternPool.LoadedUnionType, zcu: *const Zcu) Zcu.UnionLayout { |
| 3916 | 3916 | const ip = &zcu.intern_pool; |
| 3917 | 3917 | assert(loaded_union.haveLayout(ip)); |
| 3918 | var most_aligned_field: u32 = undefined; | |
| 3919 | var most_aligned_field_size: u64 = undefined; | |
| 3920 | var biggest_field: u32 = undefined; | |
| 3918 | var most_aligned_field: u32 = 0; | |
| 3919 | var most_aligned_field_align: InternPool.Alignment = .@"1"; | |
| 3920 | var most_aligned_field_size: u64 = 0; | |
| 3921 | var biggest_field: u32 = 0; | |
| 3921 | 3922 | var payload_size: u64 = 0; |
| 3922 | 3923 | var payload_align: InternPool.Alignment = .@"1"; |
| 3923 | for (loaded_union.field_types.get(ip), 0..) |field_ty, field_index| { | |
| 3924 | if (Type.fromInterned(field_ty).isNoReturn(zcu)) continue; | |
| 3924 | for (loaded_union.field_types.get(ip), 0..) |field_ty_ip_index, field_index| { | |
| 3925 | const field_ty: Type = .fromInterned(field_ty_ip_index); | |
| 3926 | if (field_ty.isNoReturn(zcu)) continue; | |
| 3925 | 3927 | |
| 3926 | 3928 | const explicit_align = loaded_union.fieldAlign(ip, field_index); |
| 3927 | 3929 | const field_align = if (explicit_align != .none) |
| 3928 | 3930 | explicit_align |
| 3929 | 3931 | else |
| 3930 | Type.fromInterned(field_ty).abiAlignment(zcu); | |
| 3931 | if (Type.fromInterned(field_ty).hasRuntimeBits(zcu)) { | |
| 3932 | const field_size = Type.fromInterned(field_ty).abiSize(zcu); | |
| 3933 | if (field_size > payload_size) { | |
| 3934 | payload_size = field_size; | |
| 3935 | biggest_field = @intCast(field_index); | |
| 3936 | } | |
| 3937 | if (field_align.compare(.gte, payload_align)) { | |
| 3938 | most_aligned_field = @intCast(field_index); | |
| 3939 | most_aligned_field_size = field_size; | |
| 3940 | } | |
| 3932 | field_ty.abiAlignment(zcu); | |
| 3933 | const field_size = field_ty.abiSize(zcu); | |
| 3934 | if (field_size > payload_size) { | |
| 3935 | payload_size = field_size; | |
| 3936 | biggest_field = @intCast(field_index); | |
| 3937 | } | |
| 3938 | if (field_size > 0 and field_align.compare(.gte, most_aligned_field_align)) { | |
| 3939 | most_aligned_field = @intCast(field_index); | |
| 3940 | most_aligned_field_align = field_align; | |
| 3941 | most_aligned_field_size = field_size; | |
| 3941 | 3942 | } |
| 3942 | 3943 | payload_align = payload_align.max(field_align); |
| 3943 | 3944 | } |