Nested arrays gives initArray and setLength undefined values

[emwap]

If initArray or setLength are passed a pointer to an uninitialized array they will cause a segmentation fault as exemplified by this code:

vectorInPairInVector :: Data WordN -> Pull DIM1 (Data WordN, Pull1 WordN)
vectorInPairInVector l = indexed1 l $ \i -> (i, indexed1 i id)

In the generated code below, the second setLength (second line in the outer loop) is fed an uninitialized value.

void test(uint32_t v0, struct s_arr_unsignedS32_1_arr_s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD_UD * out)
{
  (*out).member1 = setLength((*out).member1, sizeof(uint32_t), 1);
  at(uint32_t,(*out).member1,0) = v0;
  (*out).member2 = initArray((*out).member2, sizeof(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD), v0);
  for (uint32_t v3 = 0; v3 < v0; v3 += 1)
  {
    (at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member1 = v3;
    ((at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member2).member1 = setLength(((at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member2).member1, sizeof(uint32_t), 1);
    at(uint32_t,((at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member2).member1,0) = v3;
    ((at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member2).member2 = initArray(((at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member2).member2, sizeof(uint32_t), v3);
    for (uint32_t v6 = 0; v6 < v3; v6 += 1)
    {
      at(uint32_t,((at(struct s_unsignedS32_s_arr_unsignedS32_1_arr_unsignedS32_UD,(*out).member2,v3)).member2).member2,v6) = v6;
    }
  }
}

[pjonsson]

Is this something you hit frequently? We have a single application that suffers from this problem now that the multidim work is in the main branch.

We have type information available at compile time. Can we use that to decide whether to zero the memory block or not?

[emwap]

Yes, I have seen it when there is some nested structure in the result, e.g. Pull DIM1 (Data WordN, Pull1 WordN). Then the data structure for the inner array is not properly initialized.

Yes, I think we have enough information at compile time.