Hi Lars, Lars-Dominik Braun <l...@6xq.net> skribis:
> during testing of wip-haskell I observed the make-dynamic-linker-cache > phase is taking alot of time (up to two minutes on a fast machine with > SSD). Looking at ghc-hindent for example [1]: > > starting phase `make-dynamic-linker-cache' > created > '/gnu/store/2nrzbaxmqs2rq9yv52bpyn2azb3qj6h1-ghc-hindent-5.3.4/etc/ld.so.cache' > from 10085 library search path entries > phase `make-dynamic-linker-cache' succeeded after 119.5 seconds > > And while Haskell packages link to a pretty large number of dynamic > libraries (116 in this case), 10000 search path entries seems wrong. Running > just > > (file-needed/recursive > "/gnu/store/2nrzbaxmqs2rq9yv52bpyn2azb3qj6h1-ghc-hindent-5.3.4/bin/hindent") > > takes a long time and reveals entries like > /gnu/store/1cyk8j2nd6r0cvm6kx1408kd763yf8h5-ghc-9.2.5/lib/ghc-9.2.5/Cabal-3.6.3.0/../directory-1.3.6.2/../unix-2.7.2.2/../bytestring-0.11.3.1/../template-haskell-2.18.0.0/../pretty-1.1.3.6/../array-0.5.4.0/../base-4.16.4.0/../ghc-bignum-1.2/../ghc-prim-0.8.0/libHSghc-prim-0.8.0-ghc9.2.5.so > so it looks like it deduplicates values, but does not canonicalize > paths. A relatively straight-forward fix could be the following change, > but I don’t know if that would cause any issues, since canonicalize-path > throws an exception if the resulting path does not exist. It’s also > a world rebuild since pretty much any package uses this phase (and the > reason and I cannot test it on a larger scale). Right. Other arguments against systematic canonicalization: (1) ‘canonicalize-path’ is costly, (2) developers and tools might choose to write ‘x/y/../z’ for a good reason and changing that could break their expectations. Can you see how we end up with those entries? These at DT_NEEDED entries, not DT_RUNPATH, right? If so, that probably means that ghc at some points invokes the linker along the lines of: ld -o hindent ../foo/../bar/../baz/libbaz.so Could you check in build logs exactly how that executable gets linked? Is there a way we could canonicalize there, or, better, get the build system to do something like: ld -o hindent -L ../foo/../bar/../baz -lbaz ? That way DT_NEEDED would be just “libbaz.so” instead of the complete file name. DT_RUNPATH would contain the weird file name, but that’s probably okay. HTH, Ludo’.