Re: Fix class type lookup from OBJ_TYPE_REF

[Richard Biener <rguenther at suse dot de>]

Jan Hubicka <hubicka@ucw.cz> wrote:
>Hi,
>while working on the devirt code, I noticed that sometimes we get
>as a type of object a non-classes (like void types).  This is
>because we look up object's class from the OBJ_TYPE_REF_OBJECT
>and this is a generic pointer that gimple passes like to change
>type of.
>
>I tracked down few cases. For example when compiling passes.c one
>gets copyrename changing
>
>from
>void execute_ipa_summary_passes(ipa_opt_pass_d*) (struct ipa_opt_pass_d
>* ipa_pass)
>{
>...
>   struct opt_pass * pass
>...
>   pass_12 = ipa_pass_1;
>...
>  _20 = OBJ_TYPE_REF(_18;pass_12->3) (pass_12);
>
>
>to
>
>  ipa_pass_12 = ipa_pass_1
>...
>  _20 = OBJ_TYPE_REF(_18;ipa_pass_12->3) (ipa_pass_12);
>
>Ths makes us to believe that OBJ_TYPE_REF reffers to call of
>method of ipa_opt_pass_d instead of opt_pass.  This is wrong and
>I believe it may lead to wrong code, too - the tokens have
>different meanings.
>
>This patch changes code looking up OTR types to actually look
>into OTR type (that is pointer to method) and look the class
>type from type of the method's this pointer.
>
>Bootstrapped/regtested x86_64-linux, OK?

Ok if nobody objects.

Thanks,
Richard.

>	* tree.c (obj_type_ref_class): New function.
>	* tree.h (obj_type_ref_class): Declare.
>	* ipa-prop.c (ipa_analyze_virtual_call_uses): Use it.
>
>
>Index: tree.c
>===================================================================
>--- tree.c	(revision 201764)
>+++ tree.c	(working copy)
>@@ -11864,6 +11892,21 @@ types_same_for_odr (tree type1, tree typ
>   return true;
> }
> 
>+/* REF is OBJ_TYPE_REF, return the class the ref corresponds to.  */
>+
>+tree
>+obj_type_ref_class (tree ref)
>+{
>+  gcc_checking_assert (TREE_CODE (ref) == OBJ_TYPE_REF);
>+  ref = TREE_TYPE (ref);
>+  gcc_checking_assert (TREE_CODE (ref) == POINTER_TYPE);
>+  ref = TREE_TYPE (ref);
>+  gcc_checking_assert (TREE_CODE (ref) == METHOD_TYPE);
>+  ref = TREE_VALUE (TYPE_ARG_TYPES (ref));
>+  gcc_checking_assert (TREE_CODE (ref) == POINTER_TYPE);
>+  return TREE_TYPE (ref);
>+}
>+
>/* Try to find a base info of BINFO that would have its field decl at
>offset
>OFFSET within the BINFO type and which is of EXPECTED_TYPE.  If it can
>be
>    found, return, otherwise return NULL_TREE.  */
>Index: tree.h
>===================================================================
>--- tree.h	(revision 201764)
>+++ tree.h	(working copy)
>@@ -5974,6 +5974,7 @@ extern location_t tree_nonartificial_loc
> extern tree block_ultimate_origin (const_tree);
> 
> extern tree get_binfo_at_offset (tree, HOST_WIDE_INT, tree);
>+extern tree obj_type_ref_class (tree ref);
> extern bool types_same_for_odr (tree type1, tree type2);
> extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
> 				     HOST_WIDE_INT *, HOST_WIDE_INT *);
>Index: ipa-prop.c
>===================================================================
>--- ipa-prop.c	(revision 201764)
>+++ ipa-prop.c	(working copy)
>@@ -1903,7 +1903,7 @@ ipa_analyze_virtual_call_uses (struct cg
>   ii = cs->indirect_info;
>   ii->offset = anc_offset;
>   ii->otr_token = tree_low_cst (OBJ_TYPE_REF_TOKEN (target), 1);
>-  ii->otr_type = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (target)));
>+  ii->otr_type = obj_type_ref_class (target);
>   ii->polymorphic = 1;
> }
>