mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-02-12 20:37:54 +00:00
Code Issues Packages Projects Releases Wiki Activity

wasm: union_init correctly store the tag

Browse Source 
Previously we would only store the payload, but not the actual tag
that was set. This meant miscompilations where it would incorrectly
return the tag value.

This also adds a tiny optimization for payloads which are not `byRef`
by directly storing them based on offset, rather than first calculating
a pointer to an offset.
This commit is contained in:
Luuk de Gram 2023-05-22 19:06:38 +02:00
parent 00dedabc41
commit 49fddbf4c1
No known key found for this signature in database
GPG Key ID: A8CFE58E4DC7D664
1 changed files with 33 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
src/arch/wasm/CodeGen.zig
View File

@ -4982,26 +4982,52 @@ fn airUnionInit(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
const result = result: {
const union_ty = func.air.typeOfIndex(inst);
const layout = union_ty.unionGetLayout(func.target);
const union_obj = union_ty.cast(Type.Payload.Union).?.data;
const field = union_obj.fields.values()[extra.field_index];
const field_name = union_obj.fields.keys()[extra.field_index];
const tag_int = blk: {
const tag_ty = union_ty.unionTagTypeHypothetical();
const enum_field_index = tag_ty.enumFieldIndex(field_name).?;
var tag_val_payload: Value.Payload.U32 = .{
.base = .{ .tag = .enum_field_index },
.data = @intCast(u32, enum_field_index),
};
const tag_val = Value.initPayload(&tag_val_payload.base);
break :blk try func.lowerConstant(tag_val, tag_ty);
};
if (layout.payload_size == 0) {
if (layout.tag_size == 0) {
break :result WValue{ .none = {} };
}
assert(!isByRef(union_ty, func.target));
break :result WValue{ .imm32 = extra.field_index };
break :result tag_int;
}
assert(isByRef(union_ty, func.target));
const result_ptr = try func.allocStack(union_ty);
const payload = try func.resolveInst(extra.init);
const union_obj = union_ty.cast(Type.Payload.Union).?.data;
assert(union_obj.haveFieldTypes());
const field = union_obj.fields.values()[extra.field_index];
if (layout.tag_align >= layout.payload_align) {
const payload_ptr = try func.buildPointerOffset(result_ptr, layout.tag_size, .new);
try func.store(payload_ptr, payload, field.ty, 0);
if (isByRef(field.ty, func.target)) {
const payload_ptr = try func.buildPointerOffset(result_ptr, layout.tag_size, .new);
try func.store(payload_ptr, payload, field.ty, 0);
} else {
try func.store(result_ptr, payload, field.ty, @intCast(u32, layout.tag_size));
}
if (layout.tag_size > 0) {
try func.store(result_ptr, tag_int, union_obj.tag_ty, 0);
}
} else {
try func.store(result_ptr, payload, field.ty, 0);
if (layout.tag_size > 0) {
try func.store(
result_ptr,
tag_int,
union_obj.tag_ty,
@intCast(u32, layout.payload_size),
);
}
}
break :result result_ptr;
};