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Apparently, though unproven, at 21:58 on Thursday 21 October 2010, Grant did |
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opine thusly: |
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> I just upgraded from gcc-4.4.3-r2 to gcc-4.4.4-r2 and I'm wondering if |
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> I really need to rebuild everything as it says in the guide: |
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> |
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> http://www.gentoo.org/doc/en/gcc-upgrading.xml |
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No, you do not need to do this. The document is over-reaching (see below) |
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I ran a mixture of 4.4.3 and 4.4.4 for ages, completely trouble-free. |
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> If not, when is it necessary? |
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When you have an ABI change in the code generated by the compiler. In other |
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words, when code generated by this version is incompatible with code generated |
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by that version, and you have both on the same system. This has not happened |
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for a long time in gcc-land. |
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Now, about that official doc. Your question comes up with unbelievable |
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regularity and every time the poster references that doc. But it is not |
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necessary to do what the doc says, and a long time ago I think I figured it |
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out. |
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The author's intention is less to give you the absolute complete total 100% |
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truth that will always work out just fine, and more to reduce the amount of |
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clutter in his inbox or on b.g.o. |
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The rules about how to detect when a rebuild of world is needed are complex |
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and most readers simply will not understand them - they don't understand |
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compiler internals (how many people DO?). But if you tell people to just |
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rebuild world every time, and weird funny lurking problems are likely to just |
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get fixed as a side effect, no real harm is done. Does it hurt the author? No. |
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Does it reduce the amount of bugs he has to deal with on the rare occasion it |
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is needed? Yes. |
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What does the user lose? Nothing much, more cpu cycles get used, more bits |
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flip on a disk, your video card gets a work out scrolling all that text. Will |
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you waste time? Yes. Will you break stuff? No. |
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So rebuild world if it makes you feel better. But you don't need to this time. |
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The authors of gcc will certainly notify the entire world and it's dogs when |
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you do need to. |
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-- |
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alan dot mckinnon at gmail dot com |
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