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Hi, |
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|
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While research requirements for binary package soname dependencies [1], |
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I found that the NEEDED.ELF.2 data that portage generates contains |
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insufficient information to uniquely distinguish all of the multilib |
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ABIs that may be present on a given system [2]. In order to correctly |
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handle multilib ABIs for binary package soname dependencies, |
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preserve-libs, and other possible applications involving GLEP 64 [1], we |
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will need more information than is currently recorded in NEEDED.ELF.2. |
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|
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In order to solve this problem, I propose that we extend NEEDED.ELF.2 to |
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include a new field containing a multilib ABI identifier. The extension |
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will be backward-compatible, and NEEDED.ELF.2 will only need to be |
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regenerated on systems with multilib ABIs that are otherwise |
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indistinguishable (multilib x32 and mips systems). |
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|
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The naming convention for the multilib ABI identifiers can be derived |
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from the set of abi_* USE flags that has been established by the |
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gx86-multilib project [4]. For example, if we exclude the abi_ prefix, |
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and apply this convention to all supported architectures, then the |
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complete set of multilib ABI identifiers will be as follows: |
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|
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alpha_{32,64} |
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arm_{32,64} |
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hppa_{32,64} |
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ia_{32,64} |
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m68k_{32,64} |
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mips_{eabi32,eabi64,n32,n64,o32,o64} |
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ppc_{32,64} |
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s390_{32,64} |
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sh_{32,64} |
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sparc_{32,64} |
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x86_{32,64,x64} |
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|
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The ABIs referenced by some of the above *_32 and *_64 identifiers may |
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be imaginary, but they are listed anyway, since the goal is to establish |
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a naming convention that is as consistent and uniform as possible. The |
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OS is notably absent from these identifiers, since OS-independence is |
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one of the goals. The assumption is that, for a given installation, we |
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are only interested in tracking multilib ABIs for a single OS. |
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|
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I have attached a python script to bug 534206 [2] that can serve as a |
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reference implementation, demonstrating how a file's ELF header can be |
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used to compute a suitable multilib ABI identifier. |
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|
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Please respond with any feedback that you may have about this proposal. |
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|
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[1] http://thread.gmane.org/gmane.linux.gentoo.devel/94145 |
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[2] https://bugs.gentoo.org/show_bug.cgi?id=534206 |
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[3] https://wiki.gentoo.org/wiki/GLEP:64 |
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[4] https://wiki.gentoo.org/wiki/Gx86-multilib |
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-- |
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Thanks, |
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Zac |
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