fix JuliaLang#38224, set and use DataType.zeroinit in arrays (JuliaLa…

…ng#38444)

src/array.c

@@ -75,7 +75,7 @@ size_t jl_arr_xtralloc_limit = 0;
 #define MAXINTVAL (((size_t)-1)>>1)
 
 static jl_array_t *_new_array_(jl_value_t *atype, uint32_t ndims, size_t *dims,
- int isunboxed, int hasptr, int isunion, int elsz)
+ int8_t isunboxed, int8_t hasptr, int8_t isunion, int8_t zeroinit, int elsz)
 {
  jl_ptls_t ptls = jl_get_ptls_states();
  size_t i, tot, nel=1;
@@ -123,8 +123,6 @@ static jl_array_t *_new_array_(jl_value_t *atype, uint32_t ndims, size_t *dims,
  // No allocation or safepoint allowed after this
  a->flags.how = 0;
  data = (char*)a + doffs;
- if (tot > 0 && (!isunboxed || hasptr || isunion)) // TODO: check for zeroinit
- memset(data, 0, tot);
  }
  else {
  tsz = JL_ARRAY_ALIGN(tsz, JL_CACHE_BYTE_ALIGNMENT); // align whole object
@@ -135,12 +133,11 @@ static jl_array_t *_new_array_(jl_value_t *atype, uint32_t ndims, size_t *dims,
  // No allocation or safepoint allowed after this
  a->flags.how = 2;
  jl_gc_track_malloced_array(ptls, a);
- if (tot > 0 && (!isunboxed || hasptr || isunion)) // TODO: check for zeroinit
- // need to zero out isbits union array selector bytes to ensure a valid type index
- memset(data, 0, tot);
  }
  a->flags.pooled = tsz <= GC_MAX_SZCLASS;
 
+ if (zeroinit)
+ memset(data, 0, tot);
  a->data = data;
  if (JL_ARRAY_IMPL_NUL && elsz == 1)
  ((char*)data)[tot - 1] = '\0';
@@ -186,14 +183,15 @@ static inline jl_array_t *_new_array(jl_value_t *atype, uint32_t ndims, size_t *
  else {
  elsz = LLT_ALIGN(elsz, al);
  }
+ int zi = !isunboxed || hasptr || isunion || (jl_is_datatype(eltype) && ((jl_datatype_t*)eltype)->zeroinit);
 
- return _new_array_(atype, ndims, dims, isunboxed, hasptr, isunion, elsz);
+ return _new_array_(atype, ndims, dims, isunboxed, hasptr, isunion, zi, elsz);
 }
 
 jl_array_t *jl_new_array_for_deserialization(jl_value_t *atype, uint32_t ndims, size_t *dims,
  int isunboxed, int hasptr, int isunion, int elsz)
 {
- return _new_array_(atype, ndims, dims, isunboxed, hasptr, isunion, elsz);
+ return _new_array_(atype, ndims, dims, isunboxed, hasptr, isunion, 0, elsz);
 }
 
 #ifndef JL_NDEBUG
@@ -784,7 +782,7 @@ STATIC_INLINE void jl_array_grow_at_beg(jl_array_t *a, size_t idx, size_t inc,
  char *data = (char*)a->data;
  char *newdata;
  char *typetagdata;
- char *newtypetagdata;
+ char *newtypetagdata = NULL;
  int isbitsunion = jl_array_isbitsunion(a);
  if (isbitsunion) typetagdata = jl_array_typetagdata(a);
  if (a->offset >= inc) {
@@ -864,10 +862,10 @@ STATIC_INLINE void jl_array_grow_at_beg(jl_array_t *a, size_t idx, size_t inc,
 #endif
  a->nrows = newnrows;
  a->data = newdata;
- if (a->flags.ptrarray || a->flags.hasptr) { // TODO: check for zeroinit
+ if (jl_is_array_zeroinit(a)) {
  memset(newdata + idx * elsz, 0, nbinc);
  }
- else if (isbitsunion) {
+ if (newtypetagdata) {
  memset(newtypetagdata + idx, 0, inc);
  }
 }
@@ -945,7 +943,7 @@ STATIC_INLINE void jl_array_grow_at_end(jl_array_t *a, size_t idx,
  a->length = newnrows;
 #endif
  a->nrows = newnrows;
- if (a->flags.ptrarray || a->flags.hasptr) { // TODO: check for zeroinit
+ if (jl_is_array_zeroinit(a)) {
  memset(data + idx * elsz, 0, inc * elsz);
  }
 }
@@ -1201,7 +1199,7 @@ JL_DLLEXPORT jl_array_t *jl_array_copy(jl_array_t *ary)
  int isunion = jl_is_uniontype(jl_tparam0(jl_typeof(ary)));
  jl_array_t *new_ary = _new_array_(jl_typeof(ary), jl_array_ndims(ary),
  &ary->nrows, !ary->flags.ptrarray,
- ary->flags.hasptr, isunion, elsz);
+ ary->flags.hasptr, isunion, 0, elsz);
  memcpy(new_ary->data, ary->data, len * elsz);
  // ensure isbits union arrays copy their selector bytes correctly
  if (jl_array_isbitsunion(ary))

src/datatype.c

@@ -544,6 +544,7 @@ void jl_compute_field_offsets(jl_datatype_t *st)
  if (npointers)
  free(pointers);
  }
+ st->zeroinit = zeroinit;
  }
  // now finish deciding if this instantiation qualifies for special properties
  assert(!isbitstype || st->layout->npointers == 0); // the definition of isbits

src/dump.c

@@ -1346,7 +1346,7 @@ static jl_value_t *jl_deserialize_value_array(jl_serializer_state *s, uint8_t ta
  isptr = (elsize >> 15) & 1;
  hasptr = (elsize >> 14) & 1;
  isunion = (elsize >> 13) & 1;
- elsize = elsize & 0x3fff;
+ elsize = elsize & 0x1fff;
  }
  uintptr_t pos = backref_list.len;
  arraylist_push(&backref_list, NULL);

src/ircode.c

@@ -418,7 +418,7 @@ static jl_value_t *jl_decode_value_array(jl_ircode_state *s, uint8_t tag) JL_GC_
  isptr = (elsize >> 15) & 1;
  hasptr = (elsize >> 14) & 1;
  isunion = (elsize >> 13) & 1;
- elsize = elsize & 0x3fff;
+ elsize = elsize & 0x1fff;
  }
  size_t *dims = (size_t*)alloca(ndims * sizeof(size_t));
  for (i = 0; i < ndims; i++) {

src/julia.h

@@ -1250,6 +1250,14 @@ STATIC_INLINE int jl_is_type_type(jl_value_t *v) JL_NOTSAFEPOINT
  ((jl_datatype_t*)(v))->name == ((jl_datatype_t*)jl_type_type->body)->name);
 }
 
+STATIC_INLINE int jl_is_array_zeroinit(jl_array_t *a) JL_NOTSAFEPOINT
+{
+ if (a->flags.ptrarray || a->flags.hasptr)
+ return 1;
+ jl_value_t *elty = jl_tparam0(jl_typeof(a));
+ return jl_is_datatype(elty) && ((jl_datatype_t*)elty)->zeroinit;
+}
+
 // object identity
 JL_DLLEXPORT int jl_egal(jl_value_t *a JL_MAYBE_UNROOTED, jl_value_t *b JL_MAYBE_UNROOTED) JL_NOTSAFEPOINT;
 JL_DLLEXPORT uintptr_t jl_object_id(jl_value_t *v) JL_NOTSAFEPOINT;

test/core.jl

@@ -7508,3 +7508,14 @@ let array = Int[]
 end
 @test compare_union37557(Ref{Union{Int,Vector{Int}}}(1),
  Ref{Union{Int,Vector{Int}}}(1))
+
+# issue #38224
+struct S38224
+ i::Union{Int,Missing}
+end
+@test S38224.zeroinit
+for _ in 1:5
+ let a = Vector{S38224}(undef, 1000000)
+ @test all(x->ismissing(x.i), a)
+ end
+end