From: Doug Goldstein <cardoe@cardoe.com>
To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: euan.harris@citrix.com,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH 2/2] tools: detect appropriate debug optimization level
Date: Wed, 30 Mar 2016 11:20:59 -0500 [thread overview]
Message-ID: <56FBFCEB.2050301@cardoe.com> (raw)
In-Reply-To: <22267.63547.372145.368852@mariner.uk.xensource.com>
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On 3/30/16 11:00 AM, Ian Jackson wrote:
> Doug Goldstein writes ("Re: [PATCH 2/2] tools: detect appropriate debug optimization level"):
>> On 3/8/16 9:38 AM, Wei Liu wrote:
>>> On Mon, Mar 07, 2016 at 08:23:40PM -0600, Doug Goldstein wrote:
>>>> The build should not use -O0 as that results in miscompilations. There
>>>
>>> This needs some (concrete) references. Is that a known issue in gcc? If
>>> so can you reference the bug number?
>>
>> So its not really a bug in GCC but just the complete lack of
>> optimizations in play. inlines aren't inlined. dead code elimination
>> isn't run so things are much bigger. structures aren't padded the same way.
>
> My initial reaction is that I any actual problems are bugs either in
> the compiler or in Xen, which should be fixed.
>
> There should be nothing wrong with lack of inlining or dead code
> elimination. If you can give an example of structure padding going
> wrong, please do.
>
> Ian.
>
Ok fine, I'm just confused why we're insisting on using -O0 over -Og?
From the gcc manual:
-Og
Optimize debugging experience. -Og enables optimizations that do not
interfere with debugging. It should be the optimization level of choice
for the standard edit-compile-debug cycle, offering a reasonable level
of optimization while maintaining fast compilation and a good debugging
experience.
--
Doug Goldstein
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next prev parent reply other threads:[~2016-03-30 16:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 2:23 [PATCH 1/2] libxl: ensure var is inited in libxl__domain_firmware Doug Goldstein
2016-03-08 2:23 ` [PATCH 2/2] tools: detect appropriate debug optimization level Doug Goldstein
2016-03-08 15:38 ` Wei Liu
2016-03-08 16:34 ` Doug Goldstein
2016-03-08 16:50 ` Wei Liu
2016-03-16 19:14 ` Doug Goldstein
2016-03-28 15:01 ` Doug Goldstein
2016-03-29 11:44 ` George Dunlap
2016-03-29 17:21 ` Doug Goldstein
2016-03-30 9:52 ` George Dunlap
2016-03-30 16:00 ` Ian Jackson
2016-03-30 16:11 ` Ian Jackson
2016-03-30 16:20 ` Doug Goldstein [this message]
2016-03-31 8:24 ` George Dunlap
2016-04-06 14:07 ` Ian Jackson
2016-04-06 14:34 ` George Dunlap
2016-04-06 14:57 ` Ian Jackson
2016-03-08 15:38 ` [PATCH 1/2] libxl: ensure var is inited in libxl__domain_firmware Wei Liu
2016-03-10 15:13 ` Doug Goldstein
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