From: Jan Hubicka <hubicka@ucw.cz>
To: gcc-patches@gcc.gnu.org
Subject: Fix false -Wodr warnings
Date: Mon, 15 Apr 2019 06:48:00 -0000 [thread overview]
Message-ID: <20190414205904.ojeyug5rlayaig4q@kam.mff.cuni.cz> (raw)
Hi,
this patch fixes false warning that is output when different -std
settings are used. In this case C++ FE produces same declaration in
different representations which differ by 0 sized fileds only.
The patch makes them to be ignored (and I checked we ignore them for
canonical type merging too)
Bootstrapped/regtested x86_64-linux, comitted.
Honza
PR lto/89358
* g++.dg/lto/pr89358_0.C: New testcase.
* g++.dg/lto/pr89358_1.C: New testcase.
* ipa-devirt.c (skip_in_fields_list_p): New.
(odr_types_equivalent_p): Use it.
Index: testsuite/g++.dg/lto/pr89358_0.C
===================================================================
--- testsuite/g++.dg/lto/pr89358_0.C (nonexistent)
+++ testsuite/g++.dg/lto/pr89358_0.C (working copy)
@@ -0,0 +1,11 @@
+/* { dg-do link } */
+/* { dg-options "-std=c++17" } */
+#include <map>
+
+extern void test();
+
+int main()
+{
+ std::map<int, int> m;
+ test();
+}
Index: testsuite/g++.dg/lto/pr89358_1.C
===================================================================
--- testsuite/g++.dg/lto/pr89358_1.C (nonexistent)
+++ testsuite/g++.dg/lto/pr89358_1.C (working copy)
@@ -0,0 +1,7 @@
+/* { dg-options "-std=c++14" } */
+#include <map>
+
+void test()
+{
+ std::map<int, int> m;
+}
Index: ipa-devirt.c
===================================================================
--- ipa-devirt.c (revision 270324)
+++ ipa-devirt.c (working copy)
@@ -1282,6 +1282,24 @@ warn_types_mismatch (tree t1, tree t2, l
inform (loc_t2, "the incompatible type is defined here");
}
+/* Return true if T should be ignored in TYPE_FIELDS for ODR comparsion. */
+
+static bool
+skip_in_fields_list_p (tree t)
+{
+ if (TREE_CODE (t) != FIELD_DECL)
+ return true;
+ /* C++ FE introduces zero sized fields depending on -std setting, see
+ PR89358. */
+ if (DECL_SIZE (t)
+ && integer_zerop (DECL_SIZE (t))
+ && DECL_ARTIFICIAL (t)
+ && DECL_IGNORED_P (t)
+ && !DECL_NAME (t))
+ return true;
+ return false;
+}
+
/* Compare T1 and T2, report ODR violations if WARN is true and set
WARNED to true if anything is reported. Return true if types match.
If true is returned, the types are also compatible in the sense of
@@ -1548,9 +1566,9 @@ odr_types_equivalent_p (tree t1, tree t2
f1 = TREE_CHAIN (f1), f2 = TREE_CHAIN (f2))
{
/* Skip non-fields. */
- while (f1 && TREE_CODE (f1) != FIELD_DECL)
+ while (f1 && skip_in_fields_list_p (f1))
f1 = TREE_CHAIN (f1);
- while (f2 && TREE_CODE (f2) != FIELD_DECL)
+ while (f2 && skip_in_fields_list_p (f2))
f2 = TREE_CHAIN (f2);
if (!f1 || !f2)
break;
next reply other threads:[~2019-04-14 20:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-15 6:48 Jan Hubicka [this message]
2019-04-15 12:06 ` Richard Biener
2019-04-16 12:51 Dominique d'Humières
2019-04-16 12:55 ` Jan Hubicka
2019-04-16 13:02 ` Richard Biener
2019-04-16 13:08 ` Jakub Jelinek
2019-04-16 14:18 ` Dominique d'Humières
2020-01-23 13:53 ` Thomas Schwinge
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