August 2013 - ghc-devs

Building GHCi with static linking
by Edward Z. Yang 31 Aug '13

31 Aug '13

We now build GHC with dynamic linking by default, but I recently attempted a build with static linking instead. Using: DYNAMIC_GHC_PROGRAMS=NO GhcDebugged=YES I got: "inplace/bin/ghc-stage2" -hisuf hi -osuf o -hcsuf hc -static -H64m -O -fasm -package-name vector-0.9.1 -hide-all-packages -i -ilibraries/vector/. -ilibraries/vector/dist-install/build -ilibraries/vector/dist-install/build/autogen -Ilibraries/vector/dist-install/build -Ilibraries/vector/dist-install/build/autogen -Ilibraries/vector/include -Ilibraries/vector/internal -optP-DVECTOR_BOUNDS_CHECKS -optP-include -optPlibraries/vector/dist-install/build/autogen/cabal_macros.h -package base-4.7.0.0 -package ghc-prim-0.3.1.0 -package primitive-0.4.0.1 -O2 -XHaskell98 -XCPP -XDeriveDataTypeable -O -dcore-lint -no-user-package-db -rtsopts -odir libraries/vector/dist-install/build -hidir libraries/vector/dist-install/build -stubdir libraries/vector/dist-install/build -c libraries/vector/./Data/Vector/Fusion/Stream/Monadic.hs -o libraries/vector/dist-install/build/Data/Vector/Fusion/Stream/Monadic.o Loading package ghc-prim ... <command line>: can't load .so/.DLL for: libHSghc-prim-0.3.1.0.so (libHSghc-prim-0.3.1.0.so: cannot open shared object file: No such file or directory) Is there another build flag I have to trigger? It looks like ghc-stage2 is still attempting load things dynamically. Cheers, Edward

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Nofib missing dependencies
by Edward Z. Yang 30 Aug '13

30 Aug '13

Hey Ian, I'm not sure, but I think when you made the nofib build system independent of the GHC build system, we may have lost dependency calculation for the HS files. For example, when I try to build spectral/awards, make tries to ghc -c Main.hs before it has done ghc -c QSort.hs (I hacked up the Makefile to explicitly have this dependency, but there are others). Unfortunately, my Makefile-fu is not great enough to resolve this. Do you know what is the problem? Edward

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Compiling GHC with something like distcc?
by Erik de Castro Lopo 30 Aug '13

30 Aug '13

Hi all, Does anyone have any experience reports on compiling GHC with something like distcc? Don Stewart reports doing it here: http://stackoverflow.com/questions/10323419/is-there-a-distcc-like-tool-for… but there are no detail. Cheers, Erik -- ---------------------------------------------------------------------- Erik de Castro Lopo http://www.mega-nerd.com/

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include the new -flate-dmd-anal in -O2?
by Nicolas Frisby 30 Aug '13

30 Aug '13

TO: Performance czars and devs I pushed a patch yesterday enabling a second demand analysis at the end of the core2core simplification pipeline. The flag is -flate-dmd-anal, and it is off by default. My question: What's the protocol for deciding if -O2 should imply it? See http://ghc.haskell.org/trac/ghc/wiki/LateDmd for context. In particular, this section includes highlights of some nofib runs I did. http://ghc.haskell.org/trac/ghc/wiki/LateDmd#Newperformancenumbers For some tests, it decreases allocation by 10% to 20%. But on the platforms I have tried, it causes a couple repeatable slowdowns, up to 10%. I've investigated a bit, but haven't found any clear explanations. I'm worried that it's caching effects, eg. Any suggestions on how I should proceed with my investigation? Also: I'd appreciate if any developer would generously run some benchmarks on various platforms they might have and add them to the same section in the wiki page. http://ghc.haskell.org/trac/ghc/wiki/LateDmd#Newperformancenumbers NB That it is unfortunately key to build the libraries twice: once with -flate-dmd-anal in GhcLibHcOpts and once without. I have not determined how to do this robustly without a distclean — please let me know if you have a better method. So I've used # one of the following #GhcLibHcOpts = -O2 # both with and without -flate-dmd-anal GhcLibHcOpts = -O2 -flate-dmd-anal SplitObjs = NO DYNAMIC_BY_DEFAULT = NO DYNAMIC_GHC_PROGRAMS = NO The last three aren't necessary, but please record what you use, if you are so generous as to run it :). Thanks.

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Re: Cannot make ghc: Failed to load interface for GHC.Base
by Dan Rosén 30 Aug '13

30 Aug '13

No! Sorry for the confusion Simon, it is HEAD _PLUS_ my own commit that triggers these errors. Oh, and I should add that 'my own commit' is only in my own development repository. So, no worries! /Dan On Fri, Aug 30, 2013 at 4:44 PM, Simon Peyton-Jones <simonpj(a)microsoft.com>wrote: > Wait.. are you saying that with HEAD several test suite programs fail as > you describe below? If so, which? > > Simion**** > > ** ** > > *From:* ghc-devs [mailto:ghc-devs-bounces@haskell.org] *On Behalf Of *Dan > Rosén > *Sent:* 30 August 2013 14:26 > *To:* David Luposchainsky > *Cc:* ghc-devs(a)haskell.org > *Subject:* Re: Cannot make ghc: Failed to load interface for GHC.Base**** > > ** ** > > Closed, but a note to interested readers: > > killy9999 on #ghc realized the reason why the stage1 compiler cannot be > built with this patch is related to that several test suite programs exit > with erros like this:**** > > GHC/Base.lhs:1:1:**** > > GHC internal error: 'GHC.Base.Monad' is not in scope during type checking, but it passed the renamer**** > > tcl_env of environment: []**** > > > So the error is resolved, and now productive debugging can start.**** > > ** ** > > On Fri, Aug 30, 2013 at 2:50 PM, Dan Rosén <danr(a)chalmers.se> wrote:**** > > Sorry! I thought I got this build error when making HEAD, but I don't. > It builds fine. > > However, if I just cherry-pick this simple commit onto HEAD > https://github.com/danr/ghc/commit/86631ffd294af320cb9b00e1a593201af887ed72 > , > then I do get this error, which is very puzzling. I did a make > maintainer-clean in between. **** > > ** ** > > On Thu, Aug 29, 2013 at 6:05 PM, David Luposchainsky < > dluposchainsky(a)googlemail.com> wrote:**** > > On 2013-08-29 18:03, Austin Seipp wrote: > > When was the last time you cleaned your tree? Earlier this week I made a > > breaking change to the interface file format. If you have a build from > > before then, update and incrementally rebuild, it will break.**** > > I tried all of clean, distclean and maintainer-clean, followed by the > usual build process. The issue remains.**** > > > David > > > _______________________________________________ > ghc-devs mailing list > ghc-devs(a)haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs**** > > ** ** > > ** ** >

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Re: Cannot make ghc: Failed to load interface for GHC.Base
by Dan Rosén 30 Aug '13

30 Aug '13

Closed, but a note to interested readers: killy9999 on #ghc realized the reason why the stage1 compiler cannot be built with this patch is related to that several test suite programs exit with erros like this: GHC/Base.lhs:1:1: GHC internal error: 'GHC.Base.Monad' is not in scope during type checking, but it passed the renamer tcl_env of environment: [] So the error is resolved, and now productive debugging can start. On Fri, Aug 30, 2013 at 2:50 PM, Dan Rosén <danr(a)chalmers.se> wrote: > Sorry! I thought I got this build error when making HEAD, but I don't. > It builds fine. > > However, if I just cherry-pick this simple commit onto HEAD > https://github.com/danr/ghc/commit/86631ffd294af320cb9b00e1a593201af887ed72 > , > then I do get this error, which is very puzzling. I did a make > maintainer-clean in between. > > > > On Thu, Aug 29, 2013 at 6:05 PM, David Luposchainsky < > dluposchainsky(a)googlemail.com> wrote: > >> On 2013-08-29 18:03, Austin Seipp wrote: >> > When was the last time you cleaned your tree? Earlier this week I made a >> > breaking change to the interface file format. If you have a build from >> > before then, update and incrementally rebuild, it will break. >> >> I tried all of clean, distclean and maintainer-clean, followed by the >> usual build process. The issue remains. >> >> David >> >> >> _______________________________________________ >> ghc-devs mailing list >> ghc-devs(a)haskell.org >> http://www.haskell.org/mailman/listinfo/ghc-devs >> > >

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Re: Cannot make ghc: Failed to load interface for GHC.Base
by Dan Rosén 30 Aug '13

30 Aug '13

Sorry! I thought I got this build error when making HEAD, but I don't. It builds fine. However, if I just cherry-pick this simple commit onto HEAD https://github.com/danr/ghc/commit/86631ffd294af320cb9b00e1a593201af887ed72, then I do get this error, which is very puzzling. I did a make maintainer-clean in between. On Thu, Aug 29, 2013 at 6:05 PM, David Luposchainsky < dluposchainsky(a)googlemail.com> wrote: > On 2013-08-29 18:03, Austin Seipp wrote: > > When was the last time you cleaned your tree? Earlier this week I made a > > breaking change to the interface file format. If you have a build from > > before then, update and incrementally rebuild, it will break. > > I tried all of clean, distclean and maintainer-clean, followed by the > usual build process. The issue remains. > > David > > > _______________________________________________ > ghc-devs mailing list > ghc-devs(a)haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs >

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RE: [Haskell-cafe] Announcing GHC iOS
by Simon Peyton-Jones 30 Aug '13

30 Aug '13

Congratulations! And thank you! GHC only thrives because people like you and Stephen are willing to put in the cycles to help. Simon From: Haskell-Cafe [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Luke Iannini Sent: 29 August 2013 21:44 To: Haskell Cafe Subject: [Haskell-cafe] Announcing GHC iOS Hi all! (in case you don't read /r/haskell : )) Stephen Blackheath and I are extremely happy to report that as of today, GHC can natively build binaries for iOS devices and the iOS Simulator. You'll find everything you need here: http://ghc.haskell.org/trac/ghc/wiki/Building/CrossCompiling/iOS The short of it is you can use "ghc-ios myFiles.hs" to get a universal ARMv7/ARMv7s/i386 static library to drop straight into an Xcode project. Stephen's already working on some wonderful FRP-powered games, I'm working on a project called SpaceTime that I'll announce shortly, and you may now all begin creating insanely great iOS software using the finest language in the world : ). Stephen deserves the lion's share of the credit for this project - it's been over 3 years in the making! Many thanks to Maxwell Swadling for generalizing static library builds into a -staticlib flag for GHC, Carter Schonwald for compilation guidance, and the venerable Austin Seipp for reviewing and merging our patches.

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Design discussion for atomic primops to land in 7.8
by Ryan Newton 29 Aug '13

29 Aug '13

There's a ticket that describes the design here: http://ghc.haskell.org/trac/ghc/ticket/8157#comment:1 It is a fairly simple extension of the casMutVar# that has been in since 7.2. The implementation is on the `atomics` branch currently. Feel free to add your views either here or on that task's comments. One example of an alternative design would be Carter's proposal to expose something closer to the full LLVM concurrency ops<http://llvm.org/docs/Atomics.html> : Schonwald <carter.schonwald(a)gmail.com> wrote: > i'm kinda thinking that we should do the analogue of exposing all the > different memory model level choices (because its not that hard to add > that), and when the person building it has an old version of GCC, it falls > back to the legacy atomic operations? > > This also gives a nice path to how to upgrade to the inline asm approach. > These LLVM ops include many parameterized configurations of loads, stores, cmpxchg, atomicrmw and barriers. In fact, it implements much more than is natively supported in most hardware, but it provides a uniform abstraction. My original thought was that any kind of abstraction like that would be built and maintained as a Haskell library, and only the most rudimentary operations (required to get access to process features) would be exposed as primops. Let's call this the "small" set of concurrent ops. If we want the "big set" I think we're doomed to *reproduce* the logic that maps LLVM concurrency abstractions onto machine ops irrespective of whether those abstractions are implemented as Haskell functions or as primops: - If the former, then the Haskell library must map the full set of ops to the reduced small set (just like LLVM does internally) - If we instead have a large set of LLVM-isomorphic primops.... then to support the same primops *in the native code backend *will, again, require reimplementing all configurations of all operations. Unless... we want to make concurrency ops something that require the LLVM backend? Right now there is not a *performance* disadvantage to supporting a smaller rather than a larger set of concurrency ops (LLVM has to emulate these things anyway, or "round up" to more expensive ops). The scenario where it would be good to target ALL of LLVMs interface would be if processors and LLVM improved in the future, and we automatically got the benefit of better HW support for some op on on some arch. I'm a bit skeptical of that proposition itself, however. I personally don't really like a world where we program with "virtual operations" that don't really exist (and thus can't be *tested* against properly). Absent formal verification, it seems hard to get this code right anyway. Errors will be undetectable on existing architectures. -Ryan

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heads up: new .hi format
by Nicolas Frisby 29 Aug '13

29 Aug '13

FYI I just pushed a commit (cf http://ghc.haskell.org/trac/ghc/wiki/LateDmd) that changes the format of the .hi files — so it's safest to do a full rebuild once you pull it.

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