Hi,
this patch fixes verify_type ICE while building Ada. The problem is that
we end up with INTEGER_TYPE that has TYPE_ALIAS_SET buts its main variant
is integer_type_node that is built in LTO and has non-zero alias set.
This is will lead to wrong code if function using integer built with
-fno-strit-aliasing gets inlined, but I am not fixing this (dunno how).
This patch merely disables streaming of TYPE_ALIAS_SET==0 for non-main
variants, because it is consistently ignored by get_alias_set anyway and adds
corresponding testing. I also took liberty to optimize
pack_ts_type_common_value_fields by ordering the constant flags first and
turning TYPE_ALIAS_SET streaming to a bit instead of var_len_int that is either
0 or -1.
I suppose -fno-strict-aliasing can be saved only by making all TYPE_ALIAS_SET==0
types variant and making get_alias_set honor it. When mixing -fstrict-aliasing
and -fno-strict-aliasing we will have different type variants on each code
which will stick. THe canonical type machinery then can preffer the non-0
variant.
This seems like a deeper change - at least I do not see how to make prestreamed
types to work with this sense easily. Another variant would be to put the info
directly to MEM_REF that is probably better and easier and drop forcing
TYPE_ALIAS_SET==0. Then however we will need to wrap all memory accesses into
MEM_REF, even non-LTO.
Bootstrapped/regtested x86_64-linux with and without LTO including ada.
Requires the earlier VECTOR_TYPE change to pass cleanly testsuite, otherwise it
fails on 2 vectorizer testcases.
OK?
Honza
* alias.c (get_alias_set): Before checking TYPE_ALIAS_SET_KNOWN_P
double check that type is main variant.
* tree.c (build_variant_type_copy): Clear TYPE_ALIAS_SET when producing
variant.
(verify_type_variant): Verify that variants have no
TYPE_ALIAS_SET_KNOWN_P set
* tree-streamer-out.c (pack_ts_type_common_value_fields): Reorder
streaming so constant fields come first; stream TYPE_ALIAS_SET==0
only for main variants; stream TYPE_ALIAS_SET as a bit.
* tree-streamer-in.c (unpack_ts_type_common_value_fields): Update
accordingly.
Index: alias.c
===================================================================
--- alias.c (revision 230783)
+++ alias.c (working copy)
@@ -888,6 +888,7 @@ get_alias_set (tree t)
}
/* If this is a type with a known alias set, return it. */
+ gcc_checking_assert (t == TYPE_MAIN_VARIANT (t));
if (TYPE_ALIAS_SET_KNOWN_P (t))
return TYPE_ALIAS_SET (t);
@@ -1025,6 +1026,7 @@ get_alias_set (tree t)
We can not call get_alias_set (p) here as that would trigger
infinite recursion when p == t. In other cases it would just
trigger unnecesary legwork of rebuilding the pointer again. */
+ gcc_checking_assert (p == TYPE_MAIN_VARIANT (p));
if (TYPE_ALIAS_SET_KNOWN_P (p))
set = TYPE_ALIAS_SET (p);
else
Index: tree.c
===================================================================
--- tree.c (revision 230783)
+++ tree.c (working copy)
@@ -6706,6 +6706,7 @@ build_variant_type_copy (tree type)
/* Since we're building a variant, assume that it is a non-semantic
variant. This also propagates TYPE_STRUCTURAL_EQUALITY_P. */
TYPE_CANONICAL (t) = TYPE_CANONICAL (type);
+ /* Type variants have no alias set defined. */
+ TYPE_ALIAS_SET (t) = -1;
/* Add the new type to the chain of variants of TYPE. */
TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
@@ -13056,8 +13058,12 @@ verify_type_variant (const_tree t, tree
if ((!in_lto_p || !TYPE_FILE_SCOPE_P (t)) && 0)
verify_variant_match (TYPE_CONTEXT);
verify_variant_match (TYPE_STRING_FLAG);
- if (TYPE_ALIAS_SET_KNOWN_P (t) && TYPE_ALIAS_SET_KNOWN_P (tv))
- verify_variant_match (TYPE_ALIAS_SET);
+ if (TYPE_ALIAS_SET_KNOWN_P (t))
+ {
+ error ("type variant with TYPE_ALIAS_SET_KNOWN_P");
+ return false;
+ }
/* tree_type_non_common checks. */
Index: tree-streamer-out.c
===================================================================
--- tree-streamer-out.c (revision 230783)
+++ tree-streamer-out.c (working copy)
@@ -313,6 +313,17 @@ pack_ts_type_common_value_fields (struct
/* TYPE_NO_FORCE_BLK is private to stor-layout and need
no streaming. */
bp_pack_value (bp, TYPE_NEEDS_CONSTRUCTING (expr), 1);
+ bp_pack_value (bp, TYPE_PACKED (expr), 1);
+ bp_pack_value (bp, TYPE_RESTRICT (expr), 1);
+ bp_pack_value (bp, TYPE_USER_ALIGN (expr), 1);
+ bp_pack_value (bp, TYPE_READONLY (expr), 1);
+ /* Make sure to preserve the fact whether the frontend would assign
+ alias-set zero to this type. Do that only for main variants, because
+ type variants alias sets are never computed.
+ FIXME: This does not work for pre-streamed builtin types. */
+ bp_pack_value (bp, (TYPE_ALIAS_SET (expr) == 0
+ || (!in_lto_p && TYPE_MAIN_VARIANT (expr) == expr
+ && get_alias_set (expr) == 0)), 1);
if (RECORD_OR_UNION_TYPE_P (expr))
{
bp_pack_value (bp, TYPE_TRANSPARENT_AGGR (expr), 1);
@@ -320,17 +331,8 @@ pack_ts_type_common_value_fields (struct
}
else if (TREE_CODE (expr) == ARRAY_TYPE)
bp_pack_value (bp, TYPE_NONALIASED_COMPONENT (expr), 1);
- bp_pack_value (bp, TYPE_PACKED (expr), 1);
- bp_pack_value (bp, TYPE_RESTRICT (expr), 1);
- bp_pack_value (bp, TYPE_USER_ALIGN (expr), 1);
- bp_pack_value (bp, TYPE_READONLY (expr), 1);
bp_pack_var_len_unsigned (bp, TYPE_PRECISION (expr));
bp_pack_var_len_unsigned (bp, TYPE_ALIGN (expr));
- /* Make sure to preserve the fact whether the frontend would assign
- alias-set zero to this type. */
- bp_pack_var_len_int (bp, (TYPE_ALIAS_SET (expr) == 0
- || (!in_lto_p
- && get_alias_set (expr) == 0)) ? 0 : -1);
}
Index: tree-streamer-in.c
===================================================================
--- tree-streamer-in.c (revision 230783)
+++ tree-streamer-in.c (working copy)
@@ -362,6 +362,11 @@ unpack_ts_type_common_value_fields (stru
/* TYPE_NO_FORCE_BLK is private to stor-layout and need
no streaming. */
TYPE_NEEDS_CONSTRUCTING (expr) = (unsigned) bp_unpack_value (bp, 1);
+ TYPE_PACKED (expr) = (unsigned) bp_unpack_value (bp, 1);
+ TYPE_RESTRICT (expr) = (unsigned) bp_unpack_value (bp, 1);
+ TYPE_USER_ALIGN (expr) = (unsigned) bp_unpack_value (bp, 1);
+ TYPE_READONLY (expr) = (unsigned) bp_unpack_value (bp, 1);
+ TYPE_ALIAS_SET (expr) = bp_unpack_value (bp, 1) ? 0 : -1;
if (RECORD_OR_UNION_TYPE_P (expr))
{
TYPE_TRANSPARENT_AGGR (expr) = (unsigned) bp_unpack_value (bp, 1);
@@ -369,17 +374,12 @@ unpack_ts_type_common_value_fields (stru
}
else if (TREE_CODE (expr) == ARRAY_TYPE)
TYPE_NONALIASED_COMPONENT (expr) = (unsigned) bp_unpack_value (bp, 1);
- TYPE_PACKED (expr) = (unsigned) bp_unpack_value (bp, 1);
- TYPE_RESTRICT (expr) = (unsigned) bp_unpack_value (bp, 1);
- TYPE_USER_ALIGN (expr) = (unsigned) bp_unpack_value (bp, 1);
- TYPE_READONLY (expr) = (unsigned) bp_unpack_value (bp, 1);
TYPE_PRECISION (expr) = bp_unpack_var_len_unsigned (bp);
TYPE_ALIGN (expr) = bp_unpack_var_len_unsigned (bp);
#ifdef ACCEL_COMPILER
if (TYPE_ALIGN (expr) > targetm.absolute_biggest_alignment)
TYPE_ALIGN (expr) = targetm.absolute_biggest_alignment;
#endif
- TYPE_ALIAS_SET (expr) = bp_unpack_var_len_int (bp);
}
