We crash on an assert in strip_typedefs, because we find ourselves in a
scenario where RESULT, the main variant of a struct, was modified in
finalize_record_size (its TYPE_ALIGN changed), but its variants (T in
strip_typedefs) weren't fixed-up yet; that will happen slightly later in
finalize_type_size. So there's a discrepancy that confuses the code.
This patch implements what Jason suggested to me on IRC, i.e., skip the
attribute handling if RESULT is complete and T isn't.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2017-03-08 Marek Polacek <pola...@redhat.com>
PR c++/79900 - ICE in strip_typedefs
* tree.c (strip_typedefs): Skip the attribute handling if T is
a variant type which hasn't been updated yet.
* g++.dg/warn/Wpadded-1.C: New test.
diff --git gcc/cp/tree.c gcc/cp/tree.c
index d3c63b8..b3a4a10 100644
--- gcc/cp/tree.c
+++ gcc/cp/tree.c
@@ -1548,29 +1548,40 @@ strip_typedefs (tree t, bool *remove_attributes)
result = TYPE_MAIN_VARIANT (t);
}
gcc_assert (!typedef_variant_p (result));
- if (TYPE_USER_ALIGN (t) != TYPE_USER_ALIGN (result)
- || TYPE_ALIGN (t) != TYPE_ALIGN (result))
+
+ if (COMPLETE_TYPE_P (result) && !COMPLETE_TYPE_P (t))
+ /* If RESULT is complete and T isn't, it's likely the case that T
+ is a variant of RESULT which hasn't been updated yet. Skip the
+ attribute handling. */;
+ else
{
- gcc_assert (TYPE_USER_ALIGN (t));
- if (remove_attributes)
- *remove_attributes = true;
- else
+ if (TYPE_USER_ALIGN (t) != TYPE_USER_ALIGN (result)
+ || TYPE_ALIGN (t) != TYPE_ALIGN (result))
{
- if (TYPE_ALIGN (t) == TYPE_ALIGN (result))
- result = build_variant_type_copy (result);
+ gcc_assert (TYPE_USER_ALIGN (t));
+ if (remove_attributes)
+ *remove_attributes = true;
else
- result = build_aligned_type (result, TYPE_ALIGN (t));
- TYPE_USER_ALIGN (result) = true;
+ {
+ if (TYPE_ALIGN (t) == TYPE_ALIGN (result))
+ result = build_variant_type_copy (result);
+ else
+ result = build_aligned_type (result, TYPE_ALIGN (t));
+ TYPE_USER_ALIGN (result) = true;
+ }
+ }
+
+ if (TYPE_ATTRIBUTES (t))
+ {
+ if (remove_attributes)
+ result = apply_identity_attributes (result, TYPE_ATTRIBUTES (t),
+ remove_attributes);
+ else
+ result = cp_build_type_attribute_variant (result,
+ TYPE_ATTRIBUTES (t));
}
}
- if (TYPE_ATTRIBUTES (t))
- {
- if (remove_attributes)
- result = apply_identity_attributes (result, TYPE_ATTRIBUTES (t),
- remove_attributes);
- else
- result = cp_build_type_attribute_variant (result, TYPE_ATTRIBUTES (t));
- }
+
return cp_build_qualified_type (result, cp_type_quals (t));
}
diff --git gcc/testsuite/g++.dg/warn/Wpadded-1.C
gcc/testsuite/g++.dg/warn/Wpadded-1.C
index e69de29..b3f0581 100644
--- gcc/testsuite/g++.dg/warn/Wpadded-1.C
+++ gcc/testsuite/g++.dg/warn/Wpadded-1.C
@@ -0,0 +1,22 @@
+// PR c++/79900 - ICE in strip_typedefs
+// { dg-do compile }
+// { dg-options "-Wpadded" }
+
+template <class> struct A;
+template <typename> struct B { // { dg-warning "padding struct size to
alignment boundary" }
+ long _M_off;
+ int _M_state;
+};
+template <> struct A<char> { typedef B<int> pos_type; };
+enum _Ios_Openmode {};
+struct C {
+ typedef _Ios_Openmode openmode;
+};
+template <typename, typename _Traits> struct D {
+ typedef typename _Traits::pos_type pos_type;
+ pos_type m_fn1(pos_type, C::openmode);
+};
+template class D<char, A<char> >;
+template <typename _CharT, typename _Traits>
+typename D<_CharT, _Traits>::pos_type D<_CharT, _Traits>::m_fn1(pos_type x,
+ C::openmode) {
return x; }
Marek
