On Sat, Jun 28, 2014 at 8:26 PM, Jan Hubicka <hubi...@ucw.cz> wrote:
> Hi,
> this is another bug noticed. Here ipa-devirt attempts to merge binfos of two
> representations
> of the same ODR type, but forgets about variants.
>
> I also noticed that using variant instead of the type may end up in
> incomplete type and/or
> we may waste polymorphic call target cache by duplicated entries. I made the
> contextes to
> be always main variants thus.
>
> Bootstrapped, lto-bootstrapped/regtested x86_64-linux, comitted.
>
> * ipa-devirt.c (set_type_binfo): New function.
> (add_type_duplicate): Use it.
> (get_odr_type): Sanity check that binfos points to main variants.
> (get_class_context): Be sure the context's outer_type is main variant.
> (contains_type_p): Walk main variant.
> (get_polymorphic_call_info_for_decl): Set outer_type to be main
> variant.
> (get_polymorphic_call_info): Likewise.
> (possible_polymorphic_call_targets): Sanity check that we operate on
> main
> variant.
> Index: ipa-devirt.c
> ===================================================================
> --- ipa-devirt.c (revision 212098)
> +++ ipa-devirt.c (working copy)
> @@ -334,6 +334,17 @@ static odr_hash_type *odr_hash;
> static GTY(()) vec <odr_type, va_gc> *odr_types_ptr;
> #define odr_types (*odr_types_ptr)
>
> +/* Set TYPE_BINFO of TYPE and its variants to BINFO. */
> +void
> +set_type_binfo (tree type, tree binfo)
> +{
> + for (; type; type = TYPE_NEXT_VARIANT (type))
> + if (COMPLETE_TYPE_P (type))
> + TYPE_BINFO (type) = binfo;
> + else
> + gcc_assert (!TYPE_BINFO (type));
> +}
Btw - this points to the "obvious" opportunity to make variant types
a lot smaller (with the caveat to require an indirection to the main
variant to access shared bits). That would also automagically
help LTO streaming ....
Richard.
> /* TYPE is equivalent to VAL by ODR, but its tree representation differs
> from VAL->type. This may happen in LTO where tree merging did not merge
> all variants of the same type. It may or may not mean the ODR violation.
> @@ -446,16 +457,17 @@ add_type_duplicate (odr_type val, tree t
> {
> unsigned int i;
>
> - TYPE_BINFO (val->type) = TYPE_BINFO (type);
> + set_type_binfo (val->type, TYPE_BINFO (type));
> for (i = 0; i < val->types->length (); i++)
> {
> if (TYPE_BINFO ((*val->types)[i])
> == master_binfo)
> - TYPE_BINFO ((*val->types)[i]) = TYPE_BINFO (type);
> + set_type_binfo ((*val->types)[i], TYPE_BINFO (type));
> }
> + BINFO_TYPE (TYPE_BINFO (type)) = val->type;
> }
> else
> - TYPE_BINFO (type) = master_binfo;
> + set_type_binfo (type, master_binfo);
> }
> }
> }
> @@ -495,6 +507,7 @@ get_odr_type (tree type, bool insert)
>
> val = ggc_cleared_alloc<odr_type_d> ();
> val->type = type;
> + gcc_assert (BINFO_TYPE (TYPE_BINFO (val->type)) = type);
> val->bases = vNULL;
> val->derived_types = vNULL;
> val->anonymous_namespace = type_in_anonymous_namespace_p (type);
> @@ -1102,7 +1115,7 @@ get_class_context (ipa_polymorphic_call_
> if (!fld)
> goto give_up;
>
> - type = TREE_TYPE (fld);
> + type = TYPE_MAIN_VARIANT (TREE_TYPE (fld));
> offset -= pos;
> /* DECL_ARTIFICIAL represents a basetype. */
> if (!DECL_ARTIFICIAL (fld))
> @@ -1116,7 +1129,7 @@ get_class_context (ipa_polymorphic_call_
> }
> else if (TREE_CODE (type) == ARRAY_TYPE)
> {
> - tree subtype = TREE_TYPE (type);
> + tree subtype = TYPE_MAIN_VARIANT (TREE_TYPE (type));
>
> /* Give up if we don't know array size. */
> if (!tree_fits_shwi_p (TYPE_SIZE (subtype))
> @@ -1159,7 +1172,8 @@ static bool
> contains_type_p (tree outer_type, HOST_WIDE_INT offset,
> tree otr_type)
> {
> - ipa_polymorphic_call_context context = {offset, outer_type,
> + ipa_polymorphic_call_context context = {offset,
> + TYPE_MAIN_VARIANT (outer_type),
> false, true};
> return get_class_context (&context, otr_type);
> }
> @@ -1272,7 +1286,7 @@ get_polymorphic_call_info_for_decl (ipa_
> {
> gcc_assert (DECL_P (base));
>
> - context->outer_type = TREE_TYPE (base);
> + context->outer_type = TYPE_MAIN_VARIANT (TREE_TYPE (base));
> context->offset = offset;
> /* Make very conservative assumption that all objects
> may be in construction.
> @@ -1329,7 +1343,7 @@ get_polymorphic_call_info (tree fndecl,
> *otr_token = tree_to_uhwi (OBJ_TYPE_REF_TOKEN (ref));
>
> /* Set up basic info in case we find nothing interesting in the analysis.
> */
> - context->outer_type = *otr_type;
> + context->outer_type = TYPE_MAIN_VARIANT (*otr_type);
> context->offset = 0;
> base_pointer = OBJ_TYPE_REF_OBJECT (ref);
> context->maybe_derived_type = true;
> @@ -1415,7 +1429,8 @@ get_polymorphic_call_info (tree fndecl,
> if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE
> && SSA_NAME_VAR (base_pointer) == DECL_ARGUMENTS (fndecl))
> {
> - context->outer_type = TREE_TYPE (TREE_TYPE (base_pointer));
> + context->outer_type
> + = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (base_pointer)));
> gcc_assert (TREE_CODE (context->outer_type) == RECORD_TYPE);
>
> /* Dynamic casting has possibly upcasted the type
> @@ -1450,7 +1465,8 @@ get_polymorphic_call_info (tree fndecl,
> object. */
> if (DECL_BY_REFERENCE (SSA_NAME_VAR (base_pointer)))
> {
> - context->outer_type = TREE_TYPE (TREE_TYPE (base_pointer));
> + context->outer_type
> + = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (base_pointer)));
> gcc_assert (!POINTER_TYPE_P (context->outer_type));
> /* Only type inconsistent programs can have otr_type that is
> not part of outer type. */
> @@ -1599,6 +1615,8 @@ possible_polymorphic_call_targets (tree
> bool can_refer;
> bool skipped = false;
>
> + otr_type = TYPE_MAIN_VARIANT (otr_type);
> +
> /* If ODR is not initialized, return empty incomplete list. */
> if (!odr_hash)
> {
> @@ -1625,6 +1643,10 @@ possible_polymorphic_call_targets (tree
>
> type = get_odr_type (otr_type, true);
>
> + /* Recording type variants would wast results cache. */
> + gcc_assert (!context.outer_type
> + || TYPE_MAIN_VARIANT (context.outer_type) ==
> context.outer_type);
> +
> /* Lookup the outer class type we want to walk. */
> if (context.outer_type
> && !get_class_context (&context, otr_type))
> @@ -1638,6 +1660,10 @@ possible_polymorphic_call_targets (tree
> return nodes;
> }
>
> + /* Check that get_class_context kept the main variant. */
> + gcc_assert (!context.outer_type
> + || TYPE_MAIN_VARIANT (context.outer_type) ==
> context.outer_type);
> +
> /* We canonicalize our query, so we do not need extra hashtable entries.
> */
>
> /* Without outer type, we have no use for offset. Just do the
