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On Mon, Nov 30, 2015 at 12:07 AM, Anthony G. Basile <blueness@g.o> wrote: |
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> If we record enough information at build time (eg. gcc version or |
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> libcxx/clang) then we can build tools that intelligently predict if |
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> there's an abi incompatibility. |
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Yes, exactly the type of thing I'm thinking of. As you go on to note, |
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> Unfortunately gcc doesn't bump soname |
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> and/or version-info when it changes c++11 abi. |
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So, maybe kludge #1 we require is some kind of made-up section header |
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injected into object files... let's say, hypothetically, a tuple from |
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the cartesian cross-product of something vaguely like: |
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< |
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compiler={gcc34,gcc47,gcc49,gcc52,clang} |
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arch={$(< profiles/arch.list)} or maybe {(gnu target triplets)} |
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abi={c++03,c++11,gnu++11,plain-ol'-c} |
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> |
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i.e.: gcc52-amd64-gnu++11. Probably the arch is redundant -- hell, |
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maybe the compiler too -- and could be dropped... but you get the |
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idea. |
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So then, some agent digs this out from executables, and, like you say, |
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caches it in the vdb somewhere. |
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Meanwhile, suppose there's a global eselect c++abi setting. Once it's |
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changed, we could just zip through the vdb and, say, "maybe some of |
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these are false positives, but, to be safe, here's a nag to rebuild |
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these so-and-so packages, which seem to have been built against some |
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c++ abi other than the current one." |
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No depgraph required, easy to implement magically-fix-it.sh. Might |
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spin its wheels a bit but how often would you change this setting? |
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Almost never... |
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Well just thinking out loud, I probably have horrible thinkos above, |
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but ya gotta start somewhere... |
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-gmt |
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|
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Greg Turner |
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gmt@×××××××.net |
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