Reorder self-referential types checking to prevent inline allocation (#…

…33718)
JuliaLang · Oct 30, 2019 · b92a35d · b92a35d
1 parent d35134c
commit b92a35d
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Showing 2 changed files with 20 additions and 12 deletions.
diff --git a/src/datatype.c b/src/datatype.c
@@ -311,6 +311,18 @@ void jl_compute_field_offsets(jl_datatype_t *st)
         // based on whether its definition is self-referential
         if (w->types != NULL) {
             st->isbitstype = st->isinlinealloc = st->isconcretetype && !st->mutabl;
+            if (st->isinlinealloc) {
+                size_t i, nf = jl_svec_len(w->types);
+                for (i = 0; i < nf; i++) {
+                    jl_value_t *fld = jl_svecref(w->types, i);
+                    if (references_name(fld, w->name)) {
+                        st->isinlinealloc = 0;
+                        st->isbitstype = 0;
+                        st->zeroinit = 1;
+                        break;
+                    }
+                }
+            }
             size_t i, nf = jl_svec_len(st->types);
             for (i = 0; i < nf; i++) {
                 jl_value_t *fld = jl_svecref(st->types, i);
@@ -327,18 +339,6 @@ void jl_compute_field_offsets(jl_datatype_t *st)
                         st->has_concrete_subtype &= !jl_is_datatype(fld) || ((jl_datatype_t *)fld)->has_concrete_subtype;
                 }
             }
-            if (st->isinlinealloc) {
-                size_t i, nf = jl_svec_len(w->types);
-                for (i = 0; i < nf; i++) {
-                    jl_value_t *fld = jl_svecref(w->types, i);
-                    if (references_name(fld, w->name)) {
-                        st->isinlinealloc = 0;
-                        st->isbitstype = 0;
-                        st->zeroinit = 1;
-                        break;
-                    }
-                }
-            }
         }
         // If layout doesn't depend on type parameters, it's stored in st->name->wrapper
         // and reused by all subtypes.

diff --git a/test/core.jl b/test/core.jl
@@ -5924,6 +5924,14 @@ let x = UnionFieldInlineStruct(1, 3.14)
     @test CInlineUnion[end] == x
 end
 
+# issue 33709
+struct A33709
+    a::Union{Nothing,A33709}
+end
+let a33709 = A33709(A33709(nothing))
+    @test isnothing(a33709.a.a)
+end
+
 # issue 31583
 a31583 = "a"
 f31583() = a31583 === "a"