serializeCpu

pub fn serializeCpu(q: Query, buffer: *std.array_list.Managed(u8)) Allocator.Error!void {
    try buffer.ensureUnusedCapacity(8);
    switch (q.cpu_model) {
        .native => {
            buffer.appendSliceAssumeCapacity("native");
        },
        .baseline => {
            buffer.appendSliceAssumeCapacity("baseline");
        },
        .determined_by_arch_os => {
            if (q.cpu_arch == null) {
                buffer.appendSliceAssumeCapacity("native");
            } else {
                buffer.appendSliceAssumeCapacity("baseline");
            }
        },
        .explicit => |model| {
            try buffer.appendSlice(model.name);
        },
    }

    if (q.cpu_features_add.isEmpty() and q.cpu_features_sub.isEmpty()) {
        // The CPU name alone is sufficient.
        return;
    }

    const cpu_arch = q.cpu_arch orelse builtin.cpu.arch;
    const all_features = cpu_arch.allFeaturesList();

    for (all_features, 0..) |feature, i_usize| {
        const i: Target.Cpu.Feature.Set.Index = @intCast(i_usize);
        try buffer.ensureUnusedCapacity(feature.name.len + 1);
        if (q.cpu_features_sub.isEnabled(i)) {
            buffer.appendAssumeCapacity('-');
            buffer.appendSliceAssumeCapacity(feature.name);
        } else if (q.cpu_features_add.isEnabled(i)) {
            buffer.appendAssumeCapacity('+');
            buffer.appendSliceAssumeCapacity(feature.name);
        }
    }
}