From: Fangrui Song <maskray@google.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: binutils@sourceware.org, libc-alpha@sourceware.org
Subject: Re: [PATCH] elf: Support DT_RELR relative relocation format [BZ #27924]
Date: Sat, 16 Oct 2021 13:22:55 -0700 [thread overview]
Message-ID: <20211016202255.4bvzod7lxso4rny7@google.com> (raw)
In-Reply-To: <3368ef30-eb8c-8828-1af0-1a227d99dc93@suse.com>
On 2021-10-11, Jan Beulich wrote:
>On 08.10.2021 08:57, Fangrui Song via Binutils wrote:
>> --- /dev/null
>> +++ b/elf/tst-relr.c
>> @@ -0,0 +1,20 @@
>> +static int o, x;
>> +void *arr[] = {
>> + &o, &o, &o, &o, &o, &o, &o, &o, &o, &o, &o, &o, &o, &o, &o, &o,
>> + 0,
>> + &x, &x, &x, &x, &x, &x, &x, &x, &x, &x, &x, &x, &x, &x, &x, &x,
>> +};
>
>Personally I consider this overly simplistic a testcase. The two
>sequences are fully identical, have no gaps except for the one in
>the middle, and there's also no interleaving / mixing of pointers.
>None of this should matter as the specific symbol the relocation
>is for is not supposed to be of interest, but in a testcase you
>want to make sure none of this has an effect.
>
>I also wonder whether it is a good idea to have a testcase with
>"fundamentally" different behavior on 32-bit vs 64-bit: The former
>will require two RELR entries afaict, while the latter will get
>away with one here.
>
>Jan
In
https://sourceware.org/git/?p=glibc.git;a=shortlog;h=refs/heads/maskray/relr
I enhanced the test to this form:
#define ELEMS O O O O O O O O X X X X X X X O O X O O X X X E X E E O X O E
#define E 0,
#define O &o,
#define X &x,
void *arr[] = { ELEMS };
#undef O
#undef X
#define O 1,
#define X 2,
static char val[] = { ELEMS };
static int
do_test (void)
{
for (int i = 0; i < sizeof (arr) / sizeof (arr[0]); i++)
if (!((arr[i] == 0 && val[i] == 0) ||
(arr[i] == &o && val[i] == 1) ||
(arr[i] == &x && val[i] == 2)))
return 1;
return 0;
}
>> +static int
>> +do_test (void)
>> +{
>> + for (int i = 0; i < 16; i++)
>> + if (arr[i] != &o)
>> + return 1;
>> + for (int i = 17; i < 33; i++)
>> + if (arr[i] != &x)
>> + return 1;
>> + return 0;
>> +}
>> +
>> +#include <support/test-driver.c>
>>
>
next prev parent reply other threads:[~2021-10-16 20:23 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 6:57 Fangrui Song
2021-10-08 15:39 ` Florian Weimer
2021-10-08 16:36 ` Fangrui Song
2021-10-08 19:41 ` Cary Coutant
2021-10-08 16:51 ` H.J. Lu
2021-10-08 17:37 ` Fangrui Song
2021-10-08 17:43 ` H.J. Lu
2021-10-08 18:46 ` Fangrui Song
2021-10-11 7:48 ` Jan Beulich
2021-10-11 18:43 ` Fāng-ruì Sòng
2021-10-11 22:08 ` Joseph Myers
2021-10-12 8:14 ` Jan Beulich
2021-10-12 8:18 ` Jan Beulich
2021-10-12 14:09 ` H.J. Lu
2021-10-12 16:07 ` Fāng-ruì Sòng
2021-10-13 6:00 ` Jan Beulich
2021-10-13 6:13 ` Fāng-ruì Sòng
2021-10-13 6:18 ` Fāng-ruì Sòng
2021-10-18 7:59 ` Jan Beulich
2021-10-16 20:22 ` Fangrui Song [this message]
2021-10-26 23:28 ` Cary Coutant
2021-10-11 21:47 ` Joseph Myers
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