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<div class="moz-cite-prefix">On 10/30/13 7:09 PM, Philip Reames
wrote:<br>
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<div class="moz-cite-prefix">David, Quentin - Thanks for the
feedback. Responses inline.<br>
<br>
On 10/30/13 11:21 AM, David Blaikie wrote:<br>
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cite="mid:CAENS6EthtKzvRM3kv9Yxk0xidWZ_ioYFnuhaUgN2TuDdTDNk+A@mail.gmail.com"
type="cite">
<div dir="ltr">Actually CCing Eric.
<div class="gmail_extra"><br>
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<div class="gmail_quote">On Wed, Oct 30, 2013 at 11:00 AM,
Quentin Colombet <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:qcolombet@apple.com" target="_blank">qcolombet@apple.com</a>></span>
wrote:<br>
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<div>Philip,</div>
<div><br>
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<div>Thanks for the clarification.</div>
<div><br>
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<div>As far as I can tell, there is currently no way
to preserve a full and accurate stack trace while
utilizing most of LLVM’s optimization abilities.</div>
<div><br>
</div>
<div>The work on debug information may help you get
the information you need, but I do not think we will
provide information on stack frames that have been
removed via inlining or tail call. </div>
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<div><br>
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<div>In theory, at -gmlt we should emit enough debug info
to give you accurate stack traces including inlined
frames. Tail calls I assume we can't do anything about.</div>
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Tail calls I'm not too worried about. I'm reasonably sure that
our existing optimizer doesn't do any tail call optimizations.
Given that, turning them off doesn't worry me too much performance
wise.<br>
<br>
First, thank for you for mentioning the -gmit option. I had been
completely unaware of that. I'll have to dig into the
implementation and usage a bit. Can you point me to any
documentation? A quick google search didn't turn up anything. <br>
<br>
Can you clarify two things for me? First, is the intent that
-gmit *always* provide accurate stack traces? (modulo bugs of
course) If so, what is your subjective opinion on how close it
comes to meeting that goal today? (i.e. how much help would we
need to contribute to get it to a solid state?)<br>
</blockquote>
David - Redoing my google searching with "gmlt" (i.e. the correct
spelling) I see more useful links. From what I can gather, -gmlt
emits a strict subset of the debug information you'd see at -g. Are
you saying that "-g" should always be sufficient for accurate stack
traces - even in the face of inlining? This would be ideal for us.
<br>
<br>
Philip<br>
<br>
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