On Mon, Apr 15, 2024 at 10:05:58AM +0200, Jakub Jelinek wrote:
> On Mon, Apr 15, 2024 at 10:02:25AM +0200, Richard Biener wrote:
> > > Though, haven't managed to reproduce it with -O2 -flto -std=c23
> > > struct S;
> > > typedef struct S **V[10];
> > > V **foo (int x) { return 0; }
> > > struct S { int s; };
> > > either.
> > > So, maybe let's drop the ipa-free-lang-data.cc part?
> > > Seems fld_incomplete_type_of uses fld_type_variant which should
> > > copy over TYPE_CANONICAL.
> >
> > If you have a testcase that still triggers it would be nice to see it.
>
> I don't, that is why I'm now suggesting to just drop that hunk.
Actually no, I've just screwed up something in my testing.
One can reproduce it easily with -O2 -flto 20021205-1.c -std=c23
if the ipa-free-lang-data.cc hunk is removed.
This happens when fld_incomplete_type_of is called on a POINTER_TYPE
to RECORD_TYPE x, where the RECORD_TYPE x is not the TYPE_MAIN_VARIANT,
but another variant created by set_underlying_type. The
c_update_type_canonical didn't touch TYPE_CANONICAL in those, I was too
afraid I don't know what TYPE_CANONICAL should be for all variant types,
so that TREE_TYPE (t) had TYPE_CANONICAL NULL. But when we call
fld_incomplete_type_of on that TREE_TYPE (t), it sees it isn't
TYPE_MAIN_VARIANT, so calls
return (fld_type_variant
(fld_incomplete_type_of (TYPE_MAIN_VARIANT (t), fld), t, fld));
but TYPE_MAIN_VARIANT (t) has already TYPE_CANONICAL (TYPE_MAIN_VARIANT (t))
== TYPE_MAIN_VARIANT (t), that one has been completed on finish_struct.
And so we trigger the assertion, because
TYPE_CANONICAL (t2) == TYPE_CANONICAL (TREE_TYPE (t))
is no longer true, the former is non-NULL, the latter is NULL.
But looking at all the build_variant_type_copy callers and the call itself,
the call itself sets TYPE_CANONICAL to the TYPE_CANONICAL of the type on
which it is called and the only caller I can find that changes
TYPE_CANONICAL sometimes is build_qualified_type.
So, I'd hope that normally all variant types of an aggregate type (or
pointer type) have the same TYPE_CANONICAL if they have the same TYPE_QUALS
and if they have it different, they have TYPE_CANONICAL of
build_qualified_type of the base TYPE_CANONICAL.
With the following updated patch (ipa-free-lang-data.cc hunk removed,
c_update_type_canonical function updated, plus removed trailing whitespace
from tests),
make check-gcc RUNTESTFLAGS="--target_board=unix/-std=gnu23
compile.exp='20021205-1.c 20040214-2.c 20060109-1.c pr113623.c pr46866.c
pta-1.c' execute.exp='pr33870-1.c pr33870.c'"
no longer ICEs (have just expected FAILs on 20040214-2.c which isn't
compatible with C23) and make check-gcc -j32 doesn't regress compared
to the unpatched one.
Is this ok for trunk if it passes full bootstrap/regtest?
2024-04-15 Martin Uecker <uec...@tugraz.at>
Jakub Jelinek <ja...@redhat.com>
PR lto/114574
PR c/114361
gcc/c/
* c-decl.cc (shadow_tag_warned): For flag_isoc23 and code not
ENUMERAL_TYPE use SET_TYPE_STRUCTURAL_EQUALITY.
(parser_xref_tag): Likewise.
(start_struct): For flag_isoc23 use SET_TYPE_STRUCTURAL_EQUALITY.
(c_update_type_canonical): New function.
(finish_struct): Put NULL as second == operand rather than first.
Assert TYPE_STRUCTURAL_EQUALITY_P. Call c_update_type_canonical.
* c-typeck.cc (composite_type_internal): Use
SET_TYPE_STRUCTURAL_EQUALITY. Formatting fix.
gcc/testsuite/
* gcc.dg/pr114574-1.c: New test.
* gcc.dg/pr114574-2.c: New test.
* gcc.dg/pr114361.c: New test.
* gcc.dg/c23-tag-incomplete-1.c: New test.
* gcc.dg/c23-tag-incomplete-2.c: New test.
--- gcc/c/c-decl.cc.jj 2024-04-09 09:29:04.824520299 +0200
+++ gcc/c/c-decl.cc 2024-04-15 12:26:43.000790475 +0200
@@ -5051,6 +5051,8 @@ shadow_tag_warned (const struct c_declsp
if (t == NULL_TREE)
{
t = make_node (code);
+ if (flag_isoc23 && code != ENUMERAL_TYPE)
+ SET_TYPE_STRUCTURAL_EQUALITY (t);
pushtag (input_location, name, t);
}
}
@@ -8809,6 +8811,8 @@ parser_xref_tag (location_t loc, enum tr
the forward-reference will be altered into a real type. */
ref = make_node (code);
+ if (flag_isoc23 && code != ENUMERAL_TYPE)
+ SET_TYPE_STRUCTURAL_EQUALITY (ref);
if (code == ENUMERAL_TYPE)
{
/* Give the type a default layout like unsigned int
@@ -8910,6 +8914,8 @@ start_struct (location_t loc, enum tree_
if (ref == NULL_TREE || TREE_CODE (ref) != code)
{
ref = make_node (code);
+ if (flag_isoc23)
+ SET_TYPE_STRUCTURAL_EQUALITY (ref);
pushtag (loc, name, ref);
}
@@ -9347,6 +9353,45 @@ is_flexible_array_member_p (bool is_last
return false;
}
+/* Recompute TYPE_CANONICAL for variants of the type including qualified
+ versions of the type and related pointer types after an aggregate type
+ has been finalized.
+ Will not update array types, pointers to array types, function
+ types and other derived types created while the type was still
+ incomplete, those will remain TYPE_STRUCTURAL_EQUALITY_P. */
+
+static void
+c_update_type_canonical (tree t)
+{
+ for (tree x = TYPE_MAIN_VARIANT (t); x; x = TYPE_NEXT_VARIANT (x))
+ {
+ if (x != t && TYPE_STRUCTURAL_EQUALITY_P (x))
+ {
+ if (TYPE_QUALS (x) == TYPE_QUALS (t))
+ TYPE_CANONICAL (x) = TYPE_CANONICAL (t);
+ else if (TYPE_CANONICAL (t) != t
+ || check_qualified_type (x, t, TYPE_QUALS (x)))
+ TYPE_CANONICAL (x)
+ = build_qualified_type (TYPE_CANONICAL (t), TYPE_QUALS (x));
+ else
+ TYPE_CANONICAL (x) = x;
+ }
+ else if (x != t)
+ continue;
+ for (tree p = TYPE_POINTER_TO (x); p; p = TYPE_NEXT_PTR_TO (p))
+ {
+ if (!TYPE_STRUCTURAL_EQUALITY_P (p))
+ continue;
+ if (TYPE_CANONICAL (x) != x || TYPE_REF_CAN_ALIAS_ALL (p))
+ TYPE_CANONICAL (p)
+ = build_pointer_type_for_mode (TYPE_CANONICAL (x), TYPE_MODE (p),
+ false);
+ else
+ TYPE_CANONICAL (p) = p;
+ c_update_type_canonical (p);
+ }
+ }
+}
/* Fill in the fields of a RECORD_TYPE or UNION_TYPE node, T.
LOC is the location of the RECORD_TYPE or UNION_TYPE's definition.
@@ -9695,11 +9740,12 @@ finish_struct (location_t loc, tree t, t
/* Set type canonical based on equivalence class. */
if (flag_isoc23)
{
- if (NULL == c_struct_htab)
+ if (c_struct_htab == NULL)
c_struct_htab = hash_table<c_struct_hasher>::create_ggc (61);
hashval_t hash = c_struct_hasher::hash (t);
+ gcc_checking_assert (TYPE_STRUCTURAL_EQUALITY_P (t));
tree *e = c_struct_htab->find_slot_with_hash (t, hash, INSERT);
if (*e)
TYPE_CANONICAL (t) = *e;
@@ -9708,6 +9754,7 @@ finish_struct (location_t loc, tree t, t
TYPE_CANONICAL (t) = t;
*e = t;
}
+ c_update_type_canonical (t);
}
tree incomplete_vars = C_TYPE_INCOMPLETE_VARS (TYPE_MAIN_VARIANT (t));
--- gcc/c/c-typeck.cc.jj 2024-02-08 11:17:37.035662909 +0100
+++ gcc/c/c-typeck.cc 2024-04-12 17:17:33.029950025 +0200
@@ -532,6 +532,7 @@ composite_type_internal (tree t1, tree t
/* Otherwise, create a new type node and link it into the cache. */
tree n = make_node (code1);
+ SET_TYPE_STRUCTURAL_EQUALITY (n);
TYPE_NAME (n) = TYPE_NAME (t1);
struct composite_cache cache2 = { t1, t2, n, cache };
@@ -590,7 +591,8 @@ composite_type_internal (tree t1, tree t
TYPE_STUB_DECL (n) = pushdecl (build_decl (input_location, TYPE_DECL,
NULL_TREE, n));
- n = finish_struct(input_location, n, fields, attributes, NULL, &expr);
+ n = finish_struct (input_location, n, fields, attributes, NULL,
+ &expr);
n = qualify_type (n, t1);
--- gcc/testsuite/gcc.dg/pr114574-1.c.jj 2024-04-12 13:57:28.647782827
+0200
+++ gcc/testsuite/gcc.dg/pr114574-1.c 2024-04-12 13:57:28.647782827 +0200
@@ -0,0 +1,7 @@
+/* PR lto/114574
+ * { dg-do compile }
+ * { dg-options "-flto" } */
+
+const struct S * x;
+struct S {};
+void f(const struct S **);
--- gcc/testsuite/gcc.dg/pr114574-2.c.jj 2024-04-12 13:57:28.647782827
+0200
+++ gcc/testsuite/gcc.dg/pr114574-2.c 2024-04-12 13:57:28.647782827 +0200
@@ -0,0 +1,7 @@
+/* PR lto/114574
+ * { dg-do compile }
+ * { dg-options "-flto -std=c23" } */
+
+const struct S * x;
+struct S {};
+void f(const struct S **);
--- gcc/testsuite/gcc.dg/pr114361.c.jj 2024-04-12 13:57:28.684782327 +0200
+++ gcc/testsuite/gcc.dg/pr114361.c 2024-04-12 13:57:28.684782327 +0200
@@ -0,0 +1,10 @@
+/* PR c/114361 */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu23 -g" } */
+
+void f()
+{
+ typedef struct foo bar;
+ typedef __typeof( ({ (struct foo { bar *x; }){ }; }) ) wuz;
+ struct foo { wuz *x; };
+}
--- gcc/testsuite/gcc.dg/c23-tag-incomplete-1.c.jj 2024-04-12
13:57:28.684782327 +0200
+++ gcc/testsuite/gcc.dg/c23-tag-incomplete-1.c 2024-04-12 13:57:28.684782327
+0200
@@ -0,0 +1,11 @@
+/* { dg-do compile }
+ * { dg-options "-std=c23 -g" } */
+
+struct a;
+typedef struct a b;
+
+void g() {
+ struct a { b* x; };
+}
+
+struct a { b* x; };
--- gcc/testsuite/gcc.dg/c23-tag-incomplete-2.c.jj 2024-04-12
13:57:28.684782327 +0200
+++ gcc/testsuite/gcc.dg/c23-tag-incomplete-2.c 2024-04-12 13:57:28.684782327
+0200
@@ -0,0 +1,11 @@
+/* { dg-do compile }
+ * { dg-options "-std=c23 -g" } */
+
+struct a;
+typedef struct a b;
+
+void f() {
+ extern struct a { b* x; } t;
+}
+
+extern struct a { b* x; } t;
Jakub
