CallGeneratorHelper (in the tests) computes layouts of struct with the following code:

                long offset = 0L;
                List<MemoryLayout> layouts = new ArrayList<>();
                long align = 0;
                for (StructFieldType field : fields) {
                    MemoryLayout l = field.layout();
                    long padding = offset % l.bitAlignment();
                    if (padding != 0) {
                        layouts.add(MemoryLayout.paddingLayout(padding));
                        offset += padding;
                    }
                    layouts.add(l.withName("field" + offset));
                    align = Math.max(align, l.bitAlignment());
                    offset += l.bitSize();
                }
                long padding = offset % align;
                if (padding != 0) {
                    layouts.add(MemoryLayout.paddingLayout(padding));
                }
                return MemoryLayout.structLayout(layouts.toArray(new MemoryLayout[0]));

However, the padding computation `offset % l.bitAlignment()` is incorrect.

Suppose we have a struct as follows:

    struct {
        char x;
        void* y;
    }

The offset after processing the first field is 8, and the alignment of the second field is 64. So the computed padding is 8 % 64 = 8 which is incorrect, as it should be 56, i.e. (64 - (8 % 64)) % 64, i.e. (l.bitAlignment() - (offset % l.bitAlignment())) % l.bitAlignment().