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Re: [patch rfa] Fix PCH test failure when -fdebug-types-section is enabled


On Fri, Apr 19, 2013 at 12:05 AM, Cary Coutant <ccoutant@google.com> wrote:
> If I turn on -fdebug-types-section, I get a failure in the PCH tests:
>
> FAIL: g++.dg/pch/system-2.C -O2 -g assembly comparison
>
> This appears to be the result of differences in hash table traversal
> during debug output (same output, slightly different order), so I'm
> thinking it's just luck that it works under the default conditions.
> The following patch fixes the problem, simply by forcing
> -fno-debug-types-section for all PCH tests, but I see no fundamental
> reason why that should be necessary. If anyone has any advice for how
> to solve the underlying problem, I'd appreciate it.

Generated code should not depend on actual values of pointers - which
often happens when you traverse a hashtable hashing pointers.  Is this
what is done here?  Then I suggest to hash on something different or
sort after sth different before outputting.

Richard.

> -cary
>
>
> Index: lib/dg-pch.exp
> ===================================================================
> --- lib/dg-pch.exp      (revision 198068)
> +++ lib/dg-pch.exp      (working copy)
> @@ -139,5 +139,5 @@ proc dg-flags-pch { subdir test otherfla
>  }
>
>  proc dg-pch { subdir test options suffix } {
> -  return [dg-flags-pch $subdir $test "" $options $suffix]
> +  return [dg-flags-pch $subdir $test "-fno-debug-types-section"
> $options $suffix]
>  }


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