Re: Fix false -Wodr warnings

[Thomas Schwinge <thomas@codesourcery.com>]

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Hi!

On 2019-04-15T13:55:39+0200, Richard Biener <richard.guenther@gmail.com> wrote:
> On Sun, Apr 14, 2019 at 10:59 PM Jan Hubicka <hubicka@ucw.cz> wrote:
>> 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.

In 13ef7dc2448c0f9d8981577bb5448ee9b6842b1c "Backport
d2a0371d2641e85c5e6ca396029be32204d976df", Martin backported this to
releases/gcc-8, but without including the fix-up for...

> The testcase is bogus
>
> WARNING: lto.exp does not support dg-do
> WARNING: lto.exp does not support dg-options in primary source file

... that one.  As obvious, pushed Dominique's trunk r270390/commit
ef9387d8fe79219a106c3f9d6c6a87b0a9065d54 to releases/gcc-8 in
8e55f241ab8c754a2ab8ec2fe39afd9173589401 "pr89358_0.C: Replace dg-* with
dg-lto-*.", see attached.


Grüße
 Thomas


>>         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;



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From 8e55f241ab8c754a2ab8ec2fe39afd9173589401 Mon Sep 17 00:00:00 2001
From: Dominique d'Humieres <dominiq@gcc.gnu.org>
Date: Tue, 16 Apr 2019 15:24:58 +0200
Subject: [PATCH] pr89358_0.C: Replace dg-* with dg-lto-*.

2019-04-16  Dominique d'Humieres  <dominiq@gcc.gnu.org>

	* g++.dg/lto/pr89358_0.C: Replace dg-* with dg-lto-*.

(cherry picked from trunk r270390/commit ef9387d8fe79219a106c3f9d6c6a87b0a9065d54)
---
 gcc/testsuite/ChangeLog              | 7 +++++++
 gcc/testsuite/g++.dg/lto/pr89358_0.C | 4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6c2c5559b9b5..1d0ed10a84ac 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2020-01-23  Thomas Schwinge  <thomas@codesourcery.com>
+
+	Backport:
+	2019-04-16  Dominique d'Humieres  <dominiq@gcc.gnu.org>
+
+	* g++.dg/lto/pr89358_0.C: Replace dg-* with dg-lto-*.
+
 2020-01-22  Joseph Myers  <joseph@codesourcery.com>
 
 	Backport from mainline:
diff --git a/gcc/testsuite/g++.dg/lto/pr89358_0.C b/gcc/testsuite/g++.dg/lto/pr89358_0.C
index aebd2127c0cf..328c60c2fb18 100644
--- a/gcc/testsuite/g++.dg/lto/pr89358_0.C
+++ b/gcc/testsuite/g++.dg/lto/pr89358_0.C
@@ -1,5 +1,5 @@
-/* { dg-do link } */
-/* { dg-options "-std=c++17"  } */
+/* { dg-lto-do link } */
+/* { dg-lto-options "-std=c++17"  } */
 #include <map>
 
 extern void test();
-- 
2.17.1


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