November 2014 - ghc-devs

package 'categories' fails with HEAD
by Gabor Greif 05 Nov '14

05 Nov '14

Hi all, some time ago I filed: https://github.com/ekmett/categories/issues/4 against the 'categories' library. But I cannot see what is wrong with the code. It also builds with older GHCs (though I should re-check with 7.8.3). So I conjecture this is a HEAD problem in GHC HEAD. It seems weird. Any ideas what this could be? Cheers, Gabor

1 0

RE: [commit: ghc] wip/rae: Fix #1476 by making splice patterns work. (eb257c3)
by Simon Peyton Jones 04 Nov '14

04 Nov '14

| Unfortunately, splice patterns in brackets still do not work | because we don't run splices in brackets. Without running a pattern | splice, we can't know what variables it binds, so we're stuck. Not just "don't" but "can't"!! This isn't a compiler deficiency: the code is not there to run! Simon

1 0

Problem with select(2) in single threaded runtime.
by Merijn Verstraaten 04 Nov '14

04 Nov '14

While adding a test case for https://phabricator.haskell.org/D407 I noticed that while my initial patch fixed the crash for the threaded runtime, the single threaded runtime was still affected. I dove into the RTS and have hit a snag. In awaitEvent (rts/posix/Select.c) select(2) is called with the timeout computed from the Haskell call. On my current (OSX) machine my test case overflows "struct timeval", causing select to return EINVAL and crash the runtime. Unfortunately, there appears to be no portable to find the maximum size of time_t/suseconds_t (the types of the struct timeval fields), and therefore no portable way to avoid this overflow. The most practical thing I can think of is to add a configure case that checks sizeof(time_t) and sizeof(suseconds_t) and guesses they're just unsigned values of the relevant type, but I'm open to better suggestions. Alternatively, the solution is to hardcode the max value for every platform, in which case I avoid you all to tell me the maximum value on your specific platform :p Cheers, Merijn

2 5

Phab and I differ
by Simon Peyton Jones 04 Nov '14

04 Nov '14

I built and validated this commit just fine. Phab says Unexpected failures: ghci/should_run ghcirun004 [bad stdout or stderr] (ghci) rts linker_unload [bad exit code] (normal) stranal/should_compile str001 [exit code non-0] (optasm) stranal/should_compile str002 [exit code non-0] (optasm) stranal/should_compile test [exit code non-0] (optasm) but none of them fail for me. I don't know how to see enough of Phab's log to see what it thinks when wrong. (it just shows me 25 lines; clicking on "unlimited" still only shows 30 lines) | -----Original Message----- | From: noreply(a)phabricator.haskell.org | [mailto:noreply@phabricator.haskell.org] | Sent: 04 November 2014 15:32 | To: Simon Peyton Jones | Subject: [Diffusion] [Build Failed] rGHC6a1c05f01429: A little | refactoring of HsSplice and friends | | Harbormaster failed to build B1678: rGHC6a1c05f01429: A little | refactoring of HsSplice and friends! | | USERS | simonpj (Author) | GHC - Type checker/inferencer (Auditor) | GHC - Core/System FC (Auditor) | GHC - Renamer (Auditor) | GHC - HsSyn/Parser (Auditor) | | COMMIT | https://phabricator.haskell.org/rGHC6a1c05f01429 | | To: simonpj, GHC - Type checker/inferencer, GHC - Core/System FC, GHC | - Renamer, GHC - HsSyn/Parser

3 3

RE: [Diffusion] [Build Failed] rGHC652a5efe774a: Add flattening-notes
by Simon Peyton Jones 04 Nov '14

04 Nov '14

I'm seeing all these build failures, but it builds fine for me. Simon | -----Original Message----- | From: noreply(a)phabricator.haskell.org | [mailto:noreply@phabricator.haskell.org] | Sent: 04 November 2014 12:28 | To: Simon Peyton Jones | Subject: [Diffusion] [Build Failed] rGHC652a5efe774a: Add flattening- | notes | | Harbormaster failed to build B1665: rGHC652a5efe774a: Add flattening- | notes! | | USERS | simonpj (Author) | GHC - Type checker/inferencer (Auditor) | | COMMIT | https://phabricator.haskell.org/rGHC652a5efe774a | | To: simonpj, GHC - Type checker/inferencer

2 2

Re: [Msys2-users] Debugging undeterministic segfaults
by Gintautas Miliauskas 04 Nov '14

04 Nov '14

I had a problem <https://github.com/Alexpux/MSYS2-packages/issues/116> with building msys2-runtime, but debug bash installed successfully. I uncommented the hook to invoke qtcreator.exe on crashing (your .bat file needs escaping, puill request pending...), but I'm not quite sure how to check that it works. I tried building this crasher program with /usr/bin/gcc: #include <stdio.h> int main() { char *s = 0; printf("hi\n"); printf("%s\n", s); printf("bye\n"); return 0; } But running it just prints "hi", no indications of a crash or anything, regardless of the value of the MSYS variable: $ /usr/bin/gcc -o crash crash.c $ ./crash.exe hi $ echo $? 0 On Tue, Nov 4, 2014 at 1:56 AM, Ray Donnelly <mingw.android(a)gmail.com> wrote: > On Tue, Nov 4, 2014 at 12:45 AM, Gintautas Miliauskas > <gintautas.miliauskas(a)gmail.com> wrote: > > I have a suspicion that the segmentation faults are related to fork > errors, > > which appear in logs from time to time. After a few builds fork() errors > > become very frequent, and segfaults seem to occur more often. I just ran > the > > build (validate.sh) in a loop, and after a while got a bunch of > segfaults in > > Makefile rules as basic as rm invocations in the initial "make clean", > e.g.: > > > > "rm" -rf driver/split/dist > > driver/split/ghc.mk:19: recipe for target 'clean_driver/split_dist' > failed > > make[1]: *** [clean_driver/split_dist] Segmentation fault > > Makefile:94: recipe for target 'maintainer-clean' failed > > > > Closing and reopening the msys2 console seems to help - for some time. > > Interesting .. how much process spawning do you think happens? On > MSYS2 we run massive builds (bootstrapping builds of GCC for 2 arches > for example), but MSYS2 shares a memory map, so heap corruption could > happen and cause later problems. My recommendation about building > debug bash and msys2-runtime and set > MSYS=error_start:%WD%../../mingw64/bin/qtcreator.exe|-debug|<process-id> > stands all the more then. You may need to setup path mappings in Qt C > to map from MSYS2 paths to Windows paths. You need to do this as QtC > needs to use the native GDB instead of the MSYS2 one so that QtC and > GDB are in the same pathing namespace. > > There may be a way of building msys2-runtime to check for memory > overruns too, perhaps just building it with the 'debug' option will > enable that, I'm not sure .. > > > > > > > > > > > On Tue, Nov 4, 2014 at 1:30 AM, Ray Donnelly <mingw.android(a)gmail.com> > > wrote: > >> > >> On Mon, Nov 3, 2014 at 11:07 PM, Gintautas Miliauskas > >> <gintautas.miliauskas(a)gmail.com> wrote: > >> > +ghc-devs > >> > > >> > Hi Ray, > >> > > >> > thanks for the feedback. ghc-stage1 is a native application, it is > built > >> > using a host ghc and a mingw gcc bundled with the ghc distribution (in > >> > order > >> > to keep Windows builds more predictable). The thing is, the same > builds > >> > (using make) that were stable on cygwin seem to be crashing on msys2, > >> > even > >> > though the (bundled) gcc used for the build is the same. It could be > >> > that > >> > msys2 is triggering a bug in ghc somehow, but it could be something > >> > going on > >> > in msys2 itself. > >> > > >> > The tricky part is that the crashes are rare, one in thousands of ghc > >> > invocations within a make build, and I'm having trouble pinning one > down > >> > to > >> > investigate. I'll try some basic tracing first, but ideas for > something > >> > more > >> > sophisticated would be very helpful. > >> > >> Ah, ok. I skim read your initial email and applied totally incorrect > >> weighting to the "not very hard to reproduce" bit, apologies! > >> > >> It *should* be possible to setup post-mortem debugging using either Qt > >> Creator (Tools->Options->Debugger, tick "Use Qt Creator for > >> post-mortem debugging") or Dr. Mingw > >> (https://github.com/jrfonseca/drmingw) I briefly tested both options: > >> > >> Qt Creator: It seems there's a bug in its handling of the > >> -wincrashevent command line which I've just added a note about to the > >> MINGW-packages todo list since I'd find this feature more than very > >> useful: > >> https://github.com/Alexpux/MINGW-packages/blob/master/TODO.md > >> > >> Dr Mingw: Launching the crashing executable from Windows Explorer, it > >> launches it and gives me useful information. > >> > >> Unfortunately, regardless of the debugger used, when invoking the > >> crashing executable from the mintty commandline, something inhibits > >> all post mortem debugging. I will ask the mingw-w64 guys if they know > >> what this is. I guess intrusive dialogs would be annoying, but I'd > >> like an env. var override for that I think. > >> > >> There is another possibility, and that's that bash is crashing, which > >> is an MSYS2 program. We do have a way of hooking into post-mortem > >> debugging there since Cygwin provided a way and we improved it. If you > >> check your msys2_shell.bat you'll see: > >> rem set > >> MSYS=error_start:%WD%../../mingw64/bin/qtcreator.exe|-debug|<process-id> > >> > >> If you remove the rem and make sure the path is correct (it may have > >> rotted some since I last used it) then hopefully you'll get something > >> useful. To be really useful, you should rebuild two packages, > >> MSYS2-packages/{msys2-runtime,bash}/PKGBUILD with > >> options=('debug' '!strip') > >> and then install them. > >> > >> Finally, can anyone else confirm the problem? > >> > >> There may be some edge cases when e.g. PATH is around 1024 characters, > >> I've seen some hardcoded limits in the msys2-runtime (nee Cygwin) > >> code base for things like that. I'd advise cutting your Windows PATH > >> down to just the essentials. > >> > >> Cheers, > >> > >> Ray. > >> > >> > > >> > A PKGBUILD for ghc should be feasible, although the bootstrapping is a > >> > bit > >> > tricky (some Haskell tools need to be preinstalled). I'm not sure how > >> > useful > >> > it would be since for Windows there is already a nicely packaged > native > >> > Haskell Platform installer. > >> > > >> > > >> > On Mon, Nov 3, 2014 at 3:30 AM, Ray Donnelly <mingw.android(a)gmail.com > > > >> > wrote: > >> >> > >> >> On Sun, Nov 2, 2014 at 11:45 PM, Gintautas Miliauskas > >> >> <gintautas.miliauskas(a)gmail.com> wrote: > >> >> > Hello, > >> >> > > >> >> > I have been working on building GHC, the Glasgow Haskell Compiler, > on > >> >> > Windows using msys2 [1]. We have been having some strange trouble > >> >> > with > >> >> > ghc > >> >> > segfaulting during the bootstrapping process (i.e., during make). > The > >> >> > crashes are not very hard to reproduce, but they are not > predictable > >> >> > either. > >> >> > This is almost certainly a bug in ghc itself and not with msys2 > >> >> > (although > >> >> > the crashes do not seem to occur in other environments), but I've > >> >> > been > >> >> > having some trouble pinning it down. > >> >> > > >> >> > >> >> Hi Gintuatas, > >> >> > >> >> Great. I spotted that MSYS2 was the recommended env. for GHC on > >> >> Windows, hopefully it will remain so! > >> >> > >> >> > What's a good way to debug such crashes? Is it possible to somehow > >> >> > stop > >> >> > the > >> >> > ghc process when it segfaults and attach gdb, or to dump core > somehow > >> >> > for > >> >> > later inspection? > >> >> > > >> >> > [1] > >> >> > https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Windows > >> >> > > >> >> > Here's one example crash: > >> >> > > >> >> > "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf o -hcsuf hc -static > >> >> > -H32m > >> >> > -O > >> >> > -Werror -Wall -H64m -O0 -this-package-key > >> >> > ghc_4ugNArSu5ba0Z1uHXrbTlU > >> >> > -hide-all-packages -i -icompiler/basicTypes -icompiler/cmm > >> >> > -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar > >> >> > -icompiler/ghci > >> >> > -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen > -icompiler/main > >> >> > -icompiler/nativeGen -icompiler/parser -icompiler/prelude > >> >> > -icompiler/profiling -icompiler/rename -icompiler/simplCore > >> >> > -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn > >> >> > -icompiler/stranal -icompiler/typecheck -icompiler/types > >> >> > -icompiler/utils > >> >> > -icompiler/vectorise -icompiler/stage2/build > >> >> > -icompiler/stage2/build/autogen > >> >> > -Icompiler/stage2/build -Icompiler/stage2/build/autogen > -Icompiler/. > >> >> > -Icompiler/parser -Icompiler/utils -Icompiler/../rts/dist/build > >> >> > -Icompiler/stage2 -optP-DGHCI -optP-include > >> >> > -optPcompiler/stage2/build/autogen/cabal_macros.h -package-key > >> >> > Win32_43THQMouBnk2wpnouztX1X -package-key > >> >> > array_GX4NwjS8xZkC2ZPtjgwhnz > >> >> > -package-key base_ESD4aQEEWwsHtYJVc1BwtJ -package-key > >> >> > binpa_17GphrLqCXt1H1lm4Kse1p -package-key > >> >> > bytes_Kc0PyaputnzDnBdZW0y2Gv > >> >> > -package-key conta_ChF4XLXB9JmByIycPzerow -package-key > >> >> > direc_HU5aFxMIQNwGQFzisjuinu -package-key > >> >> > filep_34DFDFT9FVD9pRLLgh8IdQ > >> >> > -package-key hoopl_IZAd44CED5NCOlpg8p2Kaj -package-key > >> >> > hpc_1QTsfQSN40FHN9p3mydARY -package-key > proce_7ZlAbRkwiRO8qgXx3NNP0G > >> >> > -package-key templ_F6UJgDtBcDIFWuHmMGEFzy -package-key > >> >> > time_HGs4JcQCd4wF6U8vJQ5fNH -package-key > trans_5jw4w9yTgmZ89ByuixDAKP > >> >> > -Wall > >> >> > -fno-warn-name-shadowing -this-package-key ghc -XHaskell2010 > >> >> > -optc-DTHREADED_RTS -DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 > -Rghc-timing > >> >> > -O2 > >> >> > -fwarn-tabs -O -dcore-lint -no-user-package-db -rtsopts -odir > >> >> > compiler/stage2/build -hidir compiler/stage2/build -stubdir > >> >> > compiler/stage2/build -c compiler/basicTypes/UniqSupply.lhs -o > >> >> > compiler/stage2/build/UniqSupply.o > >> >> > > >> >> > compiler/ghc.mk:657: recipe for target > >> >> > 'compiler/stage2/build/UniqSupply.o' > >> >> > failed > >> >> > make[1]: *** [compiler/stage2/build/UniqSupply.o] Segmentation > fault > >> >> > > >> >> > >> >> Well, it's pretty much the same story as with Linux. Build the > >> >> executable and as many libraries as you can with (something like) > >> >> "-ggdb -O0" then use gdb command line or some IDE of choice. > >> >> Personally I use Qt Creator (we have packages for this) as it can > >> >> debug external programs and, even though I don't dislike command > >> >> lines, I find debugging from them a bit too masochistic. > >> >> > >> >> Is ghc-stage1.exe an MSYS2 program or a native one? Which compiler is > >> >> it built with exactly? > >> >> > >> >> What would be involved in creating a PKGBUILD for ghc? We'd love to > >> >> have one, and it'd certainly make me a lot more inclined to dive in > to > >> >> see what's going on if one existed already. > >> >> > >> >> Ray. > >> >> > >> >> > > >> >> > -- > >> >> > Gintautas Miliauskas > >> >> > > >> >> > > >> >> > > >> >> > > ------------------------------------------------------------------------------ > >> >> > > >> >> > _______________________________________________ > >> >> > Msys2-users mailing list > >> >> > Msys2-users(a)lists.sourceforge.net > >> >> > https://lists.sourceforge.net/lists/listinfo/msys2-users > >> >> > > >> > > >> > > >> > > >> > > >> > -- > >> > Gintautas Miliauskas > > > > > > > > > > -- > > Gintautas Miliauskas > -- Gintautas Miliauskas

2 1

Major commit to the constraint solver
by Simon Peyton Jones 04 Nov '14

04 Nov '14

Friends I've pushed branch wip/new-flatten-skolems-Oct14. (It has some rebasing near the top.) It branches off master some a few days ago; i.e. it is almost completely up to date. Can you try building it? I want to push it to HEAD, but would like some independent validation first. Three things don't validate for me: * Several tests fail with ioManagerWakeup problems: reported as Trac #9722 * ghcirun002 experiences stack overflow in the bytecode interpreter, but so does HEAD: Trac #9741 * I get an odd wibble in safePk01, see this thread<https://www.haskell.org/pipermail/ghc-devs/2014-November/007065.html> with Edward I'd like to push to master soon. Thanks Simon

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Re: [GHC] #9358: Improve flag description in the user guide
by Jan Stolarek 04 Nov '14

04 Nov '14

> Jan, you said you'd be willing to do this updating before 7.10 Yes, that's the plan. The question is do I have to make it before the mid-November feature freeze? Austin, what's your opinion? > So far as I can see, there simply is no list of what is enabled by -O or > -O2. I can make such a list if you want. > It's more than a simple on/off thing because the order matters. Hmm.... in which cases does it matter? Can you give an example? Janek

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Re: [Msys2-users] Debugging undeterministic segfaults
by Gintautas Miliauskas 04 Nov '14

04 Nov '14

I have a suspicion that the segmentation faults are related to fork errors, which appear in logs from time to time. After a few builds fork() errors become very frequent, and segfaults seem to occur more often. I just ran the build (validate.sh) in a loop, and after a while got a bunch of segfaults in Makefile rules as basic as rm invocations in the initial "make clean", e.g.: "rm" -rf driver/split/dist driver/split/ghc.mk:19: recipe for target 'clean_driver/split_dist' failed make[1]: *** [clean_driver/split_dist] Segmentation fault Makefile:94: recipe for target 'maintainer-clean' failed Closing and reopening the msys2 console seems to help - for some time. On Tue, Nov 4, 2014 at 1:30 AM, Ray Donnelly <mingw.android(a)gmail.com> wrote: > On Mon, Nov 3, 2014 at 11:07 PM, Gintautas Miliauskas > <gintautas.miliauskas(a)gmail.com> wrote: > > +ghc-devs > > > > Hi Ray, > > > > thanks for the feedback. ghc-stage1 is a native application, it is built > > using a host ghc and a mingw gcc bundled with the ghc distribution (in > order > > to keep Windows builds more predictable). The thing is, the same builds > > (using make) that were stable on cygwin seem to be crashing on msys2, > even > > though the (bundled) gcc used for the build is the same. It could be that > > msys2 is triggering a bug in ghc somehow, but it could be something > going on > > in msys2 itself. > > > > The tricky part is that the crashes are rare, one in thousands of ghc > > invocations within a make build, and I'm having trouble pinning one down > to > > investigate. I'll try some basic tracing first, but ideas for something > more > > sophisticated would be very helpful. > > Ah, ok. I skim read your initial email and applied totally incorrect > weighting to the "not very hard to reproduce" bit, apologies! > > It *should* be possible to setup post-mortem debugging using either Qt > Creator (Tools->Options->Debugger, tick "Use Qt Creator for > post-mortem debugging") or Dr. Mingw > (https://github.com/jrfonseca/drmingw) I briefly tested both options: > > Qt Creator: It seems there's a bug in its handling of the > -wincrashevent command line which I've just added a note about to the > MINGW-packages todo list since I'd find this feature more than very > useful: > https://github.com/Alexpux/MINGW-packages/blob/master/TODO.md > > Dr Mingw: Launching the crashing executable from Windows Explorer, it > launches it and gives me useful information. > > Unfortunately, regardless of the debugger used, when invoking the > crashing executable from the mintty commandline, something inhibits > all post mortem debugging. I will ask the mingw-w64 guys if they know > what this is. I guess intrusive dialogs would be annoying, but I'd > like an env. var override for that I think. > > There is another possibility, and that's that bash is crashing, which > is an MSYS2 program. We do have a way of hooking into post-mortem > debugging there since Cygwin provided a way and we improved it. If you > check your msys2_shell.bat you'll see: > rem set > MSYS=error_start:%WD%../../mingw64/bin/qtcreator.exe|-debug|<process-id> > > If you remove the rem and make sure the path is correct (it may have > rotted some since I last used it) then hopefully you'll get something > useful. To be really useful, you should rebuild two packages, > MSYS2-packages/{msys2-runtime,bash}/PKGBUILD with > options=('debug' '!strip') > and then install them. > > Finally, can anyone else confirm the problem? > > There may be some edge cases when e.g. PATH is around 1024 characters, > I've seen some hardcoded limits in the msys2-runtime (nee Cygwin) > code base for things like that. I'd advise cutting your Windows PATH > down to just the essentials. > > Cheers, > > Ray. > > > > > A PKGBUILD for ghc should be feasible, although the bootstrapping is a > bit > > tricky (some Haskell tools need to be preinstalled). I'm not sure how > useful > > it would be since for Windows there is already a nicely packaged native > > Haskell Platform installer. > > > > > > On Mon, Nov 3, 2014 at 3:30 AM, Ray Donnelly <mingw.android(a)gmail.com> > > wrote: > >> > >> On Sun, Nov 2, 2014 at 11:45 PM, Gintautas Miliauskas > >> <gintautas.miliauskas(a)gmail.com> wrote: > >> > Hello, > >> > > >> > I have been working on building GHC, the Glasgow Haskell Compiler, on > >> > Windows using msys2 [1]. We have been having some strange trouble with > >> > ghc > >> > segfaulting during the bootstrapping process (i.e., during make). The > >> > crashes are not very hard to reproduce, but they are not predictable > >> > either. > >> > This is almost certainly a bug in ghc itself and not with msys2 > >> > (although > >> > the crashes do not seem to occur in other environments), but I've been > >> > having some trouble pinning it down. > >> > > >> > >> Hi Gintuatas, > >> > >> Great. I spotted that MSYS2 was the recommended env. for GHC on > >> Windows, hopefully it will remain so! > >> > >> > What's a good way to debug such crashes? Is it possible to somehow > stop > >> > the > >> > ghc process when it segfaults and attach gdb, or to dump core somehow > >> > for > >> > later inspection? > >> > > >> > [1] > https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Windows > >> > > >> > Here's one example crash: > >> > > >> > "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf o -hcsuf hc -static > -H32m > >> > -O > >> > -Werror -Wall -H64m -O0 -this-package-key > ghc_4ugNArSu5ba0Z1uHXrbTlU > >> > -hide-all-packages -i -icompiler/basicTypes -icompiler/cmm > >> > -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar > -icompiler/ghci > >> > -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen -icompiler/main > >> > -icompiler/nativeGen -icompiler/parser -icompiler/prelude > >> > -icompiler/profiling -icompiler/rename -icompiler/simplCore > >> > -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn > >> > -icompiler/stranal -icompiler/typecheck -icompiler/types > >> > -icompiler/utils > >> > -icompiler/vectorise -icompiler/stage2/build > >> > -icompiler/stage2/build/autogen > >> > -Icompiler/stage2/build -Icompiler/stage2/build/autogen -Icompiler/. > >> > -Icompiler/parser -Icompiler/utils -Icompiler/../rts/dist/build > >> > -Icompiler/stage2 -optP-DGHCI -optP-include > >> > -optPcompiler/stage2/build/autogen/cabal_macros.h -package-key > >> > Win32_43THQMouBnk2wpnouztX1X -package-key array_GX4NwjS8xZkC2ZPtjgwhnz > >> > -package-key base_ESD4aQEEWwsHtYJVc1BwtJ -package-key > >> > binpa_17GphrLqCXt1H1lm4Kse1p -package-key bytes_Kc0PyaputnzDnBdZW0y2Gv > >> > -package-key conta_ChF4XLXB9JmByIycPzerow -package-key > >> > direc_HU5aFxMIQNwGQFzisjuinu -package-key filep_34DFDFT9FVD9pRLLgh8IdQ > >> > -package-key hoopl_IZAd44CED5NCOlpg8p2Kaj -package-key > >> > hpc_1QTsfQSN40FHN9p3mydARY -package-key proce_7ZlAbRkwiRO8qgXx3NNP0G > >> > -package-key templ_F6UJgDtBcDIFWuHmMGEFzy -package-key > >> > time_HGs4JcQCd4wF6U8vJQ5fNH -package-key trans_5jw4w9yTgmZ89ByuixDAKP > >> > -Wall > >> > -fno-warn-name-shadowing -this-package-key ghc -XHaskell2010 > >> > -optc-DTHREADED_RTS -DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 -Rghc-timing > >> > -O2 > >> > -fwarn-tabs -O -dcore-lint -no-user-package-db -rtsopts -odir > >> > compiler/stage2/build -hidir compiler/stage2/build -stubdir > >> > compiler/stage2/build -c compiler/basicTypes/UniqSupply.lhs -o > >> > compiler/stage2/build/UniqSupply.o > >> > > >> > compiler/ghc.mk:657: recipe for target > >> > 'compiler/stage2/build/UniqSupply.o' > >> > failed > >> > make[1]: *** [compiler/stage2/build/UniqSupply.o] Segmentation fault > >> > > >> > >> Well, it's pretty much the same story as with Linux. Build the > >> executable and as many libraries as you can with (something like) > >> "-ggdb -O0" then use gdb command line or some IDE of choice. > >> Personally I use Qt Creator (we have packages for this) as it can > >> debug external programs and, even though I don't dislike command > >> lines, I find debugging from them a bit too masochistic. > >> > >> Is ghc-stage1.exe an MSYS2 program or a native one? Which compiler is > >> it built with exactly? > >> > >> What would be involved in creating a PKGBUILD for ghc? We'd love to > >> have one, and it'd certainly make me a lot more inclined to dive in to > >> see what's going on if one existed already. > >> > >> Ray. > >> > >> > > >> > -- > >> > Gintautas Miliauskas > >> > > >> > > >> > > ------------------------------------------------------------------------------ > >> > > >> > _______________________________________________ > >> > Msys2-users mailing list > >> > Msys2-users(a)lists.sourceforge.net > >> > https://lists.sourceforge.net/lists/listinfo/msys2-users > >> > > > > > > > > > > > -- > > Gintautas Miliauskas > -- Gintautas Miliauskas

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Re: [Msys2-users] Debugging undeterministic segfaults
by Gintautas Miliauskas 04 Nov '14

04 Nov '14

+ghc-devs Hi Ray, thanks for the feedback. ghc-stage1 is a native application, it is built using a host ghc and a mingw gcc bundled with the ghc distribution (in order to keep Windows builds more predictable). The thing is, the same builds (using make) that were stable on cygwin seem to be crashing on msys2, even though the (bundled) gcc used for the build is the same. It could be that msys2 is triggering a bug in ghc somehow, but it could be something going on in msys2 itself. The tricky part is that the crashes are rare, one in thousands of ghc invocations within a make build, and I'm having trouble pinning one down to investigate. I'll try some basic tracing first, but ideas for something more sophisticated would be very helpful. A PKGBUILD for ghc should be feasible, although the bootstrapping is a bit tricky (some Haskell tools need to be preinstalled). I'm not sure how useful it would be since for Windows there is already a nicely packaged native Haskell Platform installer. On Mon, Nov 3, 2014 at 3:30 AM, Ray Donnelly <mingw.android(a)gmail.com> wrote: > On Sun, Nov 2, 2014 at 11:45 PM, Gintautas Miliauskas > <gintautas.miliauskas(a)gmail.com> wrote: > > Hello, > > > > I have been working on building GHC, the Glasgow Haskell Compiler, on > > Windows using msys2 [1]. We have been having some strange trouble with > ghc > > segfaulting during the bootstrapping process (i.e., during make). The > > crashes are not very hard to reproduce, but they are not predictable > either. > > This is almost certainly a bug in ghc itself and not with msys2 (although > > the crashes do not seem to occur in other environments), but I've been > > having some trouble pinning it down. > > > > Hi Gintuatas, > > Great. I spotted that MSYS2 was the recommended env. for GHC on > Windows, hopefully it will remain so! > > > What's a good way to debug such crashes? Is it possible to somehow stop > the > > ghc process when it segfaults and attach gdb, or to dump core somehow for > > later inspection? > > > > [1] https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Windows > > > > Here's one example crash: > > > > "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf o -hcsuf hc -static -H32m > -O > > -Werror -Wall -H64m -O0 -this-package-key ghc_4ugNArSu5ba0Z1uHXrbTlU > > -hide-all-packages -i -icompiler/basicTypes -icompiler/cmm > > -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar -icompiler/ghci > > -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen -icompiler/main > > -icompiler/nativeGen -icompiler/parser -icompiler/prelude > > -icompiler/profiling -icompiler/rename -icompiler/simplCore > > -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn > > -icompiler/stranal -icompiler/typecheck -icompiler/types -icompiler/utils > > -icompiler/vectorise -icompiler/stage2/build > -icompiler/stage2/build/autogen > > -Icompiler/stage2/build -Icompiler/stage2/build/autogen -Icompiler/. > > -Icompiler/parser -Icompiler/utils -Icompiler/../rts/dist/build > > -Icompiler/stage2 -optP-DGHCI -optP-include > > -optPcompiler/stage2/build/autogen/cabal_macros.h -package-key > > Win32_43THQMouBnk2wpnouztX1X -package-key array_GX4NwjS8xZkC2ZPtjgwhnz > > -package-key base_ESD4aQEEWwsHtYJVc1BwtJ -package-key > > binpa_17GphrLqCXt1H1lm4Kse1p -package-key bytes_Kc0PyaputnzDnBdZW0y2Gv > > -package-key conta_ChF4XLXB9JmByIycPzerow -package-key > > direc_HU5aFxMIQNwGQFzisjuinu -package-key filep_34DFDFT9FVD9pRLLgh8IdQ > > -package-key hoopl_IZAd44CED5NCOlpg8p2Kaj -package-key > > hpc_1QTsfQSN40FHN9p3mydARY -package-key proce_7ZlAbRkwiRO8qgXx3NNP0G > > -package-key templ_F6UJgDtBcDIFWuHmMGEFzy -package-key > > time_HGs4JcQCd4wF6U8vJQ5fNH -package-key trans_5jw4w9yTgmZ89ByuixDAKP > -Wall > > -fno-warn-name-shadowing -this-package-key ghc -XHaskell2010 > > -optc-DTHREADED_RTS -DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 -Rghc-timing -O2 > > -fwarn-tabs -O -dcore-lint -no-user-package-db -rtsopts -odir > > compiler/stage2/build -hidir compiler/stage2/build -stubdir > > compiler/stage2/build -c compiler/basicTypes/UniqSupply.lhs -o > > compiler/stage2/build/UniqSupply.o > > > > compiler/ghc.mk:657: recipe for target > 'compiler/stage2/build/UniqSupply.o' > > failed > > make[1]: *** [compiler/stage2/build/UniqSupply.o] Segmentation fault > > > > Well, it's pretty much the same story as with Linux. Build the > executable and as many libraries as you can with (something like) > "-ggdb -O0" then use gdb command line or some IDE of choice. > Personally I use Qt Creator (we have packages for this) as it can > debug external programs and, even though I don't dislike command > lines, I find debugging from them a bit too masochistic. > > Is ghc-stage1.exe an MSYS2 program or a native one? Which compiler is > it built with exactly? > > What would be involved in creating a PKGBUILD for ghc? We'd love to > have one, and it'd certainly make me a lot more inclined to dive in to > see what's going on if one existed already. > > Ray. > > > > > -- > > Gintautas Miliauskas > > > > > ------------------------------------------------------------------------------ > > > > _______________________________________________ > > Msys2-users mailing list > > Msys2-users(a)lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/msys2-users > > > -- Gintautas Miliauskas

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