This is the mail archive of the libstdc++@gcc.gnu.org mailing list for the libstdc++ project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH 2/2] PR libstdc++/86756 Move rest of std::filesystem to libstdc++.so


On 23/01/19 17:01 +0100, Christophe Lyon wrote:
On Wed, 23 Jan 2019 at 16:28, Jonathan Wakely <jwakely@redhat.com> wrote:

On 09/01/19 13:53 +0100, Christophe Lyon wrote:
>On Wed, 9 Jan 2019 at 11:11, Jonathan Wakely <jwakely@redhat.com> wrote:
>>
>> On 09/01/19 10:09 +0000, Jonathan Wakely wrote:
>> >On 08/01/19 11:13 +0100, Christophe Lyon wrote:
>> >>On aarch64, I'm seeing an addtional:
>> >>FAIL: 27_io/filesystem/path/compare/strings.cc execution test
>> >>because:
>> >>/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc:39:
>> >>void test01(): Assertion 'p.compare(p0) == p.compare(s0)' failed.
>> >
>> >Odd, I don't know why that would be target-specific. It's probably
>> >just latent on other targets. I'll try to reproduce it on my aarch64
>> >system, but it will take a while to build current trunk.
>> >
>> >If you have time, could you please apply this patch, re-run that test
>>
>> *This* patch:
>>
>> --- a/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc
>> +++ b/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc
>> @@ -36,6 +36,7 @@ test01()
>>      path p(s);
>>      VERIFY( p.compare(s) == 0 );
>>      VERIFY( p.compare(s.c_str()) == 0 );
>> +    __builtin_printf("Comparing %s as path:%d as string:%d\n", s.c_str(), p.compare(p0), p.compare(s0));
>>      VERIFY( p.compare(p0) == p.compare(s0) );
>>      VERIFY( p.compare(p0) == p.compare(s0.c_str()) );
>>    }
>>
>>
>>
>>
>> >(cd $target/libstdc++-v3 && make check
>> >RUNTESTFLAGS=conformance.exp=*/path/compare/strings/cc) and send me
>> >the output from the $target/libstdc++-v3/testsuite/libstdc++.log file?
>> >
>> >On x86_64 I get:
>> >
>> >Comparing  as path:-1 as string:-1
>> >Comparing / as path:-1 as string:-1
>> >Comparing // as path:-1 as string:-1
>> >Comparing /. as path:-51 as string:-51
>> >Comparing /./ as path:-51 as string:-51
>> >Comparing /a as path:-2 as string:-2
>> >Comparing /a/ as path:-1 as string:-1
>> >Comparing /a// as path:-1 as string:-1
>> >Comparing /a/b/c/d as path:1 as string:1
>> >Comparing /a//b as path:1 as string:1
>> >Comparing a as path:-1 as string:-1
>> >Comparing a/b as path:-1 as string:-1
>> >Comparing a/b/ as path:-1 as string:-1
>> >Comparing a/b/c as path:-1 as string:-1
>> >Comparing a/b/c.d as path:-1 as string:-1
>> >Comparing a/b/.. as path:-1 as string:-1
>> >Comparing a/b/c. as path:-1 as string:-1
>> >Comparing a/b/.c as path:-1 as string:-1
>> >PASS: 27_io/filesystem/path/compare/strings.cc execution test
>> >
>
>Here is what I have on aarch64-none-elf:
>Comparing  as path:-1 as string:-1^M
>Comparing / as path:-1 as string:-1^M
>Comparing // as path:-1 as string:-1^M
>Comparing /. as path:-102 as string:-51^M
>/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc:40:
>void test01(): Assertion 'p.compare(p0) == p.compare(s0)' failed.^M
>^M
>*** EXIT code 4242^M
>emu: host signal 6^M
>FAIL: 27_io/filesystem/path/compare/strings.cc execution test

This is a strange one. With my aarch64-unknown-linux-gnu trunk build I get:

Comparing /. as path:-51 as string:-51

Which suggests it's a newlib vs glibc difference, but this target uses
glibc (right?) and has the same FAIL:
https://gcc.gnu.org/ml/gcc-testresults/2019-01/msg02276.html

Yes, it uses glibc-2.28

That build has this in its libstdc++.log:
/home/tcwg-buildslave/workspace/tcwg-buildfarm_0/snapshots/gcc.git~master_rev_2e9ceebcd7618d0e068e0029b43cd75d679022d7/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc:39:
void test01(): Assertion 'p.compare(p0) == p.compare(s0)' failed.
timeout: the monitored command dumped core
FAIL: 27_io/filesystem/path/compare/strings.cc execution test



The test should be reducable to simply:

// { dg-options "-std=gnu++17" }
#include <string>
#include <string_view>

int main()
{
  std::string_view s0 = "a";
  std::string p0(s0);
  std::string p(".");
  __builtin_printf("as path:%d as string:%d\n", p.compare(p0), p.compare(s0));
}

Again, I get -51 and -51 for this. Could you test it on
aarch64-none-elf?

In terms of what the standard requires, this comparison is based on
strcmp, i.e. it only specifies a result less than zero, equal to zero,
or greater than zero. But I'd like to know why the comparisons aren't
returning the same consistent value.


I get:
as path:-102 as string:-102

I have no idea what's going on here, so I think I will just change the
test to only care about the sign of the result, as in the attached
patch.


commit 84fc5b9d432788414e75df1f62bf8645db57f395
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Jan 24 12:53:45 2019 +0000

    Fix failing test due to inconsistent strcmp results
    
            * testsuite/27_io/filesystem/path/compare/strings.cc: Only compare
            sign of results.

diff --git a/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc b/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc
index 3f0aa4bde06..83487ae35b6 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc
@@ -26,6 +26,8 @@
 
 using std::filesystem::path;
 
+int sign(int i) { return i > 0 ? 1 : i < 0 ? -1 : 0; }
+
 void
 test01()
 {
@@ -36,8 +38,8 @@ test01()
     path p(s);
     VERIFY( p.compare(s) == 0 );
     VERIFY( p.compare(s.c_str()) == 0 );
-    VERIFY( p.compare(p0) == p.compare(s0) );
-    VERIFY( p.compare(p0) == p.compare(s0.c_str()) );
+    VERIFY( sign(p.compare(p0)) == sign(p.compare(s0)) );
+    VERIFY( sign(p.compare(p0)) == sign(p.compare(s0.c_str())) );
   }
 }
 

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]