diff mbox

adding missing LTO to some warning options (PR 78606)

Message ID 8cf050be-ad29-8f41-8120-bd1ff568b67c@mentor.com
State New
Headers show

Commit Message

Tom de Vries May 2, 2017, 10:17 a.m. UTC 
On 05/01/2017 08:05 PM, Martin Sebor wrote:
> On 04/30/2017 02:02 PM, Tom de Vries wrote:
>> On 01/10/2017 11:16 PM, Martin Sebor wrote:
>>> +  __builtin_sprintf (d, "%32s", "x");   /* { dg-warning "directive
>>> writing 32 bytes into a region of size 12" "-Wformat-length" { xfail
>>> *-*-* } } */
>>
>> This xpasses for me on an older system:
>> ...
>> XPASS: gcc.dg/pr78768.c -Wformat-overflow (test for warnings, line 11)
>> ...
>>
>> The mechanism is as follows:
>> - the system doesn't have linker plugin support, and sets
>>   HAVE_LTO_PLUGIN to 0
>> - consequently, opts.c:finish_options() sets x_flag_fat_lto_objects to 1
>>   in cc1
>> - cgraphunit.c:symbol_table::compile() does not return
>>   here:
>>   ...
>>      /* Do nothing else if any IPA pass found errors or if we are just
>>         streaming LTO.  */
>>      if (seen_error ()
>>         || (!in_lto_p && flag_lto && !flag_fat_lto_objects))
>>       {
>>         timevar_pop (TV_CGRAPHOPT);
>>         return;
>>       }
>>   ...
>>   and ends up calling expand_all_functions, which calls
>>   pass_sprintf_length
>> - the warning is generated by cc1
>>
>> Maybe the test needs:
>> ...
>> /* { dg-require-linker-plugin "" } */
>> ...
>> ?
>
> That seems possible.  IIUC, without linker plugin support the
> pass will run when the ordinary object file is created during
> the first stage of compilation.  I don't have a system to confirm
> it on but if pr78768.c xfails when you add the directive I'd say
> go ahead and commit the fix as obvious.

Done.

Thanks,
- Tom
diff mbox

Patch

Require linker plugin for pr78768.c

The test-case has an xfail-ed line.  For linkers without plugin support, that
line happens to xpass.  Require linker with plugin support, such that the line
is no longer xpass-ing, but unsupported.

2017-05-01  Tom de Vries  <tom@codesourcery.com>

	* gcc.dg/pr78768.c: Require linker plugin.

---
 gcc/testsuite/ChangeLog        | 4 ++++
 gcc/testsuite/gcc.dg/pr78768.c | 1 +
 2 files changed, 5 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/pr78768.c b/gcc/testsuite/gcc.dg/pr78768.c
index 68d717a..b6cda47 100644
--- a/gcc/testsuite/gcc.dg/pr78768.c
+++ b/gcc/testsuite/gcc.dg/pr78768.c
@@ -2,6 +2,7 @@ 
    by -flto
   { dg-do link }
   { dg-require-effective-target lto }
+  { dg-require-linker-plugin "" }
   { dg-options "-O2 -Walloca-larger-than=10 -Wformat -Wformat-overflow -flto" } */
 
 int main (void)