On Wed, Apr 19, 2017 at 07:56:30AM +0200, Jakub Jelinek wrote:
> On Wed, Apr 19, 2017 at 07:45:36AM +0200, Richard Biener wrote:
> > >As mentioned in the PR, we now use TYPE_TYPELESS_STORAGE flag on
> > >ARRAY_TYPEs to denote types that need the special C++ alias handling.
> > >The problem is how is that created, we just use build_array_type and
> > >set TYPE_TYPELESS_STORAGE on the result, but build_array_type uses type
> > >caching, so we might modify that way some other array type.
> > >If all the array type creation goes through build_cplus_array_type,
> > >that
> > >wouldn't be a problem, as that flag is dependent just on the element
> > >type, but that is not the case, c-family as well as the middle-end has
> > >lots of spots that also create array types. So in the end whether
> > >one gets TYPE_TYPELESS_STORAGE flag or not is quite random, depends on
> > >GC etc.
> > >
> > >The following patch attempts to resolve this, by making the type
> > >hashing
> > >take that flag into account. Bootstrapped/regtested on x86_64-linux
> > >and
> > >i686-linux, ok for trunk?
> >
> > When changing the C++ function I thought that calling build_array_type was
> > wrong and it should instead do the same it does in the other places, use
> > its raw creation routine and then the canonical type register stuff. But
> > I was hesitant to change this at this point.
>
> The problem is that as the patch shows, we don't need it in a single place
> (the C++ FE), but at least in two places (C++ FE and c-family), and it
> wouldn't surprise me if we don't need it later on in further places
> (e.g. in middle-end, if we have a TYPE_TYPELESS_STORAGE array and say DSE
> wants to create a smaller one with the same property).
>
> Using a default argument to build_array_type is likely cleaner indeed,
> I'd just then also swap the arguments to build_array_type_1 (the shared
> vs. typeless_storage).
Here in (so far untested) patch form:
2017-04-19 Jakub Jelinek <ja...@redhat.com>
PR middle-end/80423
* tree.h (build_array_type): Add typeless_storage default argument.
* tree.c (type_cache_hasher::equal): Also compare
TYPE_TYPELESS_STORAGE flag for ARRAY_TYPEs.
(build_array_type): Add typeless_storage argument, set
TYPE_TYPELESS_STORAGE to it, if shared also hash it, and pass to
recursive call.
(build_nonshared_array_type): Adjust build_array_type_1 caller.
(build_array_type): Likewise. Add typeless_storage argument.
c-family/
* c-common.c (complete_array_type): Preserve TYPE_TYPELESS_STORAGE.
cp/
* tree.c (build_cplus_array_type): Call build_array_type
with the intended TYPE_TYPELESS_STORAGE flag value, instead
of calling build_array_type and modifying later TYPE_TYPELESS_STORAGE
on the shared type.
testsuite/
* g++.dg/other/pr80423.C: New test.
--- gcc/tree.h.jj 2017-04-18 15:13:25.180398014 +0200
+++ gcc/tree.h 2017-04-19 08:16:12.859844328 +0200
@@ -4068,7 +4068,7 @@ extern tree build_truth_vector_type (uns
extern tree build_same_sized_truth_vector_type (tree vectype);
extern tree build_opaque_vector_type (tree innertype, int nunits);
extern tree build_index_type (tree);
-extern tree build_array_type (tree, tree);
+extern tree build_array_type (tree, tree, bool = false);
extern tree build_nonshared_array_type (tree, tree);
extern tree build_array_type_nelts (tree, unsigned HOST_WIDE_INT);
extern tree build_function_type (tree, tree);
--- gcc/tree.c.jj 2017-04-18 15:13:25.158398308 +0200
+++ gcc/tree.c 2017-04-19 08:17:50.938542960 +0200
@@ -7073,7 +7073,9 @@ type_cache_hasher::equal (type_hash *a,
break;
return 0;
case ARRAY_TYPE:
- return TYPE_DOMAIN (a->type) == TYPE_DOMAIN (b->type);
+ return (TYPE_TYPELESS_STORAGE (a->type)
+ == TYPE_TYPELESS_STORAGE (b->type)
+ && TYPE_DOMAIN (a->type) == TYPE_DOMAIN (b->type));
case RECORD_TYPE:
case UNION_TYPE:
@@ -8350,10 +8352,12 @@ subrange_type_for_debug_p (const_tree ty
/* Construct, lay out and return the type of arrays of elements with ELT_TYPE
and number of elements specified by the range of values of INDEX_TYPE.
+ If TYPELESS_STORAGE is true, TYPE_TYPELESS_STORAGE flag is set on the type.
If SHARED is true, reuse such a type that has already been constructed. */
static tree
-build_array_type_1 (tree elt_type, tree index_type, bool shared)
+build_array_type_1 (tree elt_type, tree index_type, bool typeless_storage,
+ bool shared)
{
tree t;
@@ -8367,6 +8371,7 @@ build_array_type_1 (tree elt_type, tree
TREE_TYPE (t) = elt_type;
TYPE_DOMAIN (t) = index_type;
TYPE_ADDR_SPACE (t) = TYPE_ADDR_SPACE (elt_type);
+ TYPE_TYPELESS_STORAGE (t) = typeless_storage;
layout_type (t);
/* If the element type is incomplete at this point we get marked for
@@ -8381,6 +8386,7 @@ build_array_type_1 (tree elt_type, tree
hstate.add_object (TYPE_HASH (elt_type));
if (index_type)
hstate.add_object (TYPE_HASH (index_type));
+ hstate.add_flag (typeless_storage);
t = type_hash_canon (hstate.end (), t);
}
@@ -8396,7 +8402,7 @@ build_array_type_1 (tree elt_type, tree
= build_array_type_1 (TYPE_CANONICAL (elt_type),
index_type
? TYPE_CANONICAL (index_type) : NULL_TREE,
- shared);
+ typeless_storage, shared);
}
return t;
@@ -8405,9 +8411,9 @@ build_array_type_1 (tree elt_type, tree
/* Wrapper around build_array_type_1 with SHARED set to true. */
tree
-build_array_type (tree elt_type, tree index_type)
+build_array_type (tree elt_type, tree index_type, bool typeless_storage)
{
- return build_array_type_1 (elt_type, index_type, true);
+ return build_array_type_1 (elt_type, index_type, typeless_storage, true);
}
/* Wrapper around build_array_type_1 with SHARED set to false. */
@@ -8415,7 +8421,7 @@ build_array_type (tree elt_type, tree in
tree
build_nonshared_array_type (tree elt_type, tree index_type)
{
- return build_array_type_1 (elt_type, index_type, false);
+ return build_array_type_1 (elt_type, index_type, false, false);
}
/* Return a representation of ELT_TYPE[NELTS], using indices of type
--- gcc/c-family/c-common.c.jj 2017-04-18 15:14:29.383541136 +0200
+++ gcc/c-family/c-common.c 2017-04-19 08:15:55.346076712 +0200
@@ -6386,7 +6386,6 @@ complete_array_type (tree *ptype, tree i
{
tree maxindex, type, main_type, elt, unqual_elt;
int failure = 0, quals;
- hashval_t hashcode = 0;
bool overflow_p = false;
maxindex = size_zero_node;
@@ -6480,13 +6479,15 @@ complete_array_type (tree *ptype, tree i
TYPE_DOMAIN (main_type)
= build_range_type (TREE_TYPE (maxindex),
build_int_cst (TREE_TYPE (maxindex), 0), maxindex);
+ TYPE_TYPELESS_STORAGE (main_type) = TYPE_TYPELESS_STORAGE (type);
layout_type (main_type);
/* Make sure we have the canonical MAIN_TYPE. */
- hashcode = iterative_hash_object (TYPE_HASH (unqual_elt), hashcode);
- hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (main_type)),
- hashcode);
- main_type = type_hash_canon (hashcode, main_type);
+ inchash::hash hstate;
+ hstate.add_object (TYPE_HASH (unqual_elt));
+ hstate.add_object (TYPE_HASH (TYPE_DOMAIN (main_type)));
+ hstate.add_flag (TYPE_TYPELESS_STORAGE (main_type));
+ main_type = type_hash_canon (hstate.end (), main_type);
/* Fix the canonical type. */
if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (main_type))
@@ -6497,7 +6498,8 @@ complete_array_type (tree *ptype, tree i
!= TYPE_DOMAIN (main_type)))
TYPE_CANONICAL (main_type)
= build_array_type (TYPE_CANONICAL (TREE_TYPE (main_type)),
- TYPE_CANONICAL (TYPE_DOMAIN (main_type)));
+ TYPE_CANONICAL (TYPE_DOMAIN (main_type)),
+ TYPE_TYPELESS_STORAGE (main_type));
else
TYPE_CANONICAL (main_type) = main_type;
--- gcc/cp/tree.c.jj 2017-04-18 15:13:27.136371909 +0200
+++ gcc/cp/tree.c 2017-04-19 08:15:39.191291063 +0200
@@ -949,14 +949,14 @@ build_cplus_array_type (tree elt_type, t
}
else
{
- t = build_array_type (elt_type, index_type);
- if (elt_type == unsigned_char_type_node
- || elt_type == signed_char_type_node
- || elt_type == char_type_node
- || (TREE_CODE (elt_type) == ENUMERAL_TYPE
- && TYPE_CONTEXT (elt_type) == std_node
- && !strcmp ("byte", TYPE_NAME_STRING (elt_type))))
- TYPE_TYPELESS_STORAGE (t) = 1;
+ bool typeless_storage
+ = (elt_type == unsigned_char_type_node
+ || elt_type == signed_char_type_node
+ || elt_type == char_type_node
+ || (TREE_CODE (elt_type) == ENUMERAL_TYPE
+ && TYPE_CONTEXT (elt_type) == std_node
+ && !strcmp ("byte", TYPE_NAME_STRING (elt_type))));
+ t = build_array_type (elt_type, index_type, typeless_storage);
}
/* Now check whether we already have this array variant. */
--- gcc/testsuite/g++.dg/other/pr80423.C.jj 2017-04-19 08:14:42.539042760
+0200
+++ gcc/testsuite/g++.dg/other/pr80423.C 2017-04-19 08:14:42.539042760
+0200
@@ -0,0 +1,11 @@
+// PR middle-end/80423
+// { dg-do compile { target c++11 } }
+
+typedef unsigned char uint8_t;
+struct A {
+ template <int N> A(unsigned char (&)[N]);
+};
+void fn1(A) {
+ uint8_t a[]{0};
+ fn1(a);
+}
Jakub
