November 2017 - ghc-tickets

[GHC] #13716: Move CI to Jenkins
by GHC 10 Nov '17

10 Nov '17

#13716: Move CI to Jenkins -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: None | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Currently we use Harbormaster to build Differentials and commits. While this works, it leaves much to be desired, * job scheduling is (literally) random: this means that some patch authors end up waiting literally ways for their patches to be built * there is little support for automatic provisioning of builders: this means we can't scale to meet demand and make poor use of our computational resources * periodic builds (e.g. nightlies) are not supported. Ideally we would not only provide * it doesn't have a sensible interface for integration with external tools: this means that efforts like CI-before-merge have been pushed off * status reporting is poor: even answering the question of what a given builder is currently working on is surprisingly difficult * maintenance is a byzantine: Adding a new builder requires adding at least six different objects (a Harbormaster Build Plan, a Drydock Working Copy, a Drydock Blueprint, an Almanac Service, an Almanac Device, and an Almanac Binding) in various Phabricator applications. None of this configuration can be tracked under version control nor can most of it be cloned from an existing builder's configuration. * Design assumptions don't match GHC's constraints: Harbormaster was designed under the assumption that builds are cheap and computation plentiful. The maintainers have stated that they have little interest in supporting environments where this doesn't hold. Jenkins, while far from perfect, seems a bit better suited to our needs, more mature, and far more flexible. This ticket will serve as the checklist for our move to Jenkins. In the end we want, * Builders (static or dynamically-provisioned, as appropriate) for * x86-64, i386 Linux * x86-64, i386 Windows * x86-64 Darwin * x86-64 OpenBSD * Cross compile from x86-64 to ARM * Native ARM * Differential builds with sensible scheduling (e.g. first build on 64-bit Linux where machines are cheap, then build on the others) * Per-commit builds on all * Nightly builds on all, including * Collection of binary distribution for user download * Update of `master` documentation mirror on downloads.haskell.org * Slow validation (including tests requiring Hackage packages) * nofib run on some platforms? * Test-before-merge-to-master -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13716> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12363: Type application for infix
by GHC 10 Nov '17

10 Nov '17

#12363: Type application for infix -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: lowest | Milestone: Component: Compiler | Version: 8.0.1 (Parser) | Keywords: | Operating System: Unknown/Multiple TypeApplications | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- `1 + @Int 10` is a parse error, I would like it to mean the same as {{{#!hs (+) @Int 1 10 }}} Thoughts? ---- Also {{{#!hs >>> pure `foldMap` @Maybe @[_] Just 'a' "a" >>> foldMap @Maybe @[_] pure (Just 'a') "a" }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12363> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14446: Extending TypeApplications to support infix functions
by GHC 10 Nov '17

10 Nov '17

#14446: Extending TypeApplications to support infix functions -------------------------------------+------------------------------------- Reporter: dredozubov | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- For a motivational example I propose a piece of code using a library [https://github.com/typeable/schematic] which defines a fancy record-like object and requires some type annotations: {{{ jsonExample = withRepr @SchemaExample $ field @"foo" [12] :& field @"bar" (Just "bar") :& RNil }}} By using the same function as an infix operator, it may be possible to rewrite it to something along the lines of {{{ (.=) = field jsonExample = withRepr @SchemaExample $ @"foo" .= [12] :& @"bar" .= (Just "bar") :& RNil }}} To do that, we'll need to associate a type application with the function to the right of it. I imagine it'll introduce ambiguity to the parser, but it can be dealt with by allowing a different syntactical construct for a right type application. Haven't checked with a grammar, but it can be something like this: {{{ jsonExample = withRepr @SchemaExample $ "foo"@ .= [12] :& "bar"@ .= (Just "bar") :& RNil }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14446> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4442: Add unaligned version of indexWordArray#
by GHC 10 Nov '17

10 Nov '17

#4442: Add unaligned version of indexWordArray# -------------------------------------+------------------------------------- Reporter: tibbe | Owner: (none) Type: feature request | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #14447 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by hvr): * related: => #14447 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4442#comment:16> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4442: Add unaligned version of indexWordArray#
by GHC 10 Nov '17

10 Nov '17

#4442: Add unaligned version of indexWordArray# -------------------------------------+------------------------------------- Reporter: tibbe | Owner: (none) Type: feature request | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by hvr): I just marked #14447 as a duplicate of this one -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4442#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14447: Add unaligned ByteArray# access primops
by GHC 10 Nov '17

10 Nov '17

#14447: Add unaligned ByteArray# access primops -------------------------------------+------------------------------------- Reporter: reinerp | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I would like unaligned store and unaligned load primops in GHC.Prim. Specifically: for X in {Int,Int16,Int32,Int64,Word,Word16,Word32,Word64,Float,Double,WideChar,Addr,StablePtr} and where X# is the corresponding Int#/Word#/Float#/Double#/Char#/Addr#/StablePtr# type, I'd like the following primitives: {{{#!hs -- | Reads an 'X#', offset in bytes indexXArrayOffBytes# :: ByteArray# -> Int# -> X# -- | Reads an 'X#', offset in bytes readXArrayOffBytes# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, X# #) -- | Writes an 'X#', offset in bytes writeXArrayOffBytes# :: MutableByteArray# s -> Int# -> X# -> State# s -> State# s }}} Note that the indexXOffAddr# family of functions already provides unaligned loads and similarly writeXOffAddr# provides unaligned stores, so GHC's code generator must handle these already. For example, we could use these to provide unaligned loads for pinned ByteArray#s: {{{#!hs indexWord16ArrayOffBytes# :: ByteArray# -> Int# -> Word# indexWord16ArrayOffBytes# arr offset = indexWord16OffAddr# (byteArrayContents# arr `plusAddr#` offset) 0# }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14447> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8238: Implement unloading of shared libraries
by GHC 10 Nov '17

10 Nov '17

#8238: Implement unloading of shared libraries ------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: task | Status: new Priority: normal | Milestone: 7.10.1 Component: Runtime System | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: 8039 | ------------------------------------+------------------------------------- In #8039 we added support for unloading static objects from the runtime linker, with the GC detecting when there are no references left. We could add this functionality for shared libraries too, using `dl_iterate_phdr`. @heisenbug's comment from #8039 with the relevant pointers: [http://eli.thegreenplace.net/2011/08/25/load-time-relocation-of-shared- libraries Eli Bendersky's article] suggests to use the [http://linux.die.net/man/3/dl_iterate_phdr dl_iterate_phdr] function for finding information about loaded libraries. Seems to be linux only. There is a [http://stackoverflow.com/questions/10009043/dl-iterate-phdr- equivalent-on-mac workaround on OSX], though, on !StackOverflow. And here is how Böhm-Demers-Weiser's GC implement a [https://github.com/ivmai/bdwgc/blob/master/dyn_load.c#L451 callback function for dl_iterate_phdr]. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8238> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5889: -fno-prof-count-entries leads to linking errors
by GHC 09 Nov '17

09 Nov '17

#5889: -fno-prof-count-entries leads to linking errors -------------------------------------+------------------------------------- Reporter: akio | Owner: bgamari Type: bug | Status: new Priority: highest | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: GHC rejects | (amd64) valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"e6b13c963d0b54099a41bb1b51fe680644582051/ghc" e6b13c96/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="e6b13c963d0b54099a41bb1b51fe680644582051" testsuite: Add test for #5889 Test Plan: make test TEST=5889 Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie GHC Trac Issues: #5889 Differential Revision: https://phabricator.haskell.org/D4158 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5889#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14361: GHC HEAD miscompiles `text-containers`
by GHC 09 Nov '17

09 Nov '17

#14361: GHC HEAD miscompiles `text-containers` -------------------------------------+------------------------------------- Reporter: hvr | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When compiling and running `text-containers`'s test-suite, the test-cases involving lookup functions (e.g. `member :: Key -> TextSet -> Bool`) fail indeterministically. ''more details to follow'' -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14361> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10514: Generic for existential types
by GHC 09 Nov '17

09 Nov '17

#10514: Generic for existential types -------------------------------------+------------------------------------- Reporter: | Owner: ekmett andreas.abel | Status: new Type: feature | Milestone: request | Version: 7.10.1 Priority: normal | Operating System: Unknown/Multiple Component: Core | Type of failure: None/Unknown Libraries | Blocked By: Keywords: | Related Tickets: Architecture: | Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- I have some use for Generic for an existential type which is constraint to be Generic. {{{!#hs {-# LANGUAGE DeriveGeneric #-} {-# LANGUAGE ExistentialQuantification #-} {-# LANGUAGE StandaloneDeriving #-} import GHC.Generics data U = forall a. (Generic a) => U a -- deriving (Generic) -- Can't make a derived instance of ‘Generic U’: -- Constructor ‘U’ has existentials or constraints in its type -- Possible fix: use a standalone deriving declaration instead -- deriving instance Generic U -- Can't make a derived instance of ‘Generic U’: -- U must be a vanilla data constructor -- In the stand-alone deriving instance for ‘Generic U’ data D1Ser data C1_0Ser instance Generic U where type Rep U = D D1Ser (C1 C1_0Ser (S1 NoSelector (Rep a))) -- Not in scope: type variable ‘a’ -- How to bring the existential type `a' into scope? }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10514> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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