October 2015 - ghc-tickets

[GHC] #8335: Create more specialized entries to GC
by GHC 06 Oct '15

06 Oct '15

#8335: Create more specialized entries to GC ------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | 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: | ------------------------------------+------------------------------------- Consider this Cmm code (taken from #8326): {{{ {offset cFd: // stack check if ((Sp + -16) < SpLim) goto cFr; else goto cFs; cFr: // not enough place on the stack, call GC R2 = R2; R1 = A.f_closure; call (stg_gc_fun)(R2, R1) args: 8, res: 0, upd: 8; cFs: // scrutinize (x ># 0#) _sEU::I64 = R2; _sEV::I64 = %MO_S_Gt_W64(R2, 0); if (_sEV::I64 != 1) goto cFg; else goto cFo; cFg: // False branch Hp = Hp + 16; if (Hp > HpLim) goto cFy; else goto cFx; cFy: // not enough heap, call GC HpAlloc = 16; I64[Sp - 16] = cFf; R1 = _sEV::I64; I64[Sp - 8] = _sEU::I64; Sp = Sp - 16; call stg_gc_unbx_r1(R1) returns to cFf, args: 8, res: 8, upd: 8; cFf: // re-do the False branch _sEU::I64 = I64[Sp + 8]; Sp = Sp + 16; _sEV::I64 = R1; goto cFg; cFx: // RHS of False branch I64[Hp - 8] = GHC.Types.I#_con_info; I64[Hp] = -_sEU::I64; R1 = Hp - 7; call (P64[Sp])(R1) args: 8, res: 0, upd: 8; cFo: // True branch Hp = Hp + 16; if (Hp > HpLim) goto cFv; else goto cFu; cFv: // not enough heap, call GC HpAlloc = 16; I64[Sp - 16] = cFn; R1 = _sEV::I64; I64[Sp - 8] = _sEU::I64; Sp = Sp - 16; call stg_gc_unbx_r1(R1) returns to cFn, args: 8, res: 8, upd: 8; cFn: // re-do the True branch _sEU::I64 = I64[Sp + 8]; Sp = Sp + 16; _sEV::I64 = R1; goto cFo; cFu: // RHS of True branch I64[Hp - 8] = GHC.Types.I#_con_info; I64[Hp] = _sEU::I64; R1 = Hp - 7; call (P64[Sp])(R1) args: 8, res: 0, upd: 8; } }}} We perform two different calls to garbage collection here. Calling GC after making initial stack check obviously can't use any stack, so we pass parameter to GC in regsiters: {{{ R2 = R2; R1 = A.f_closure; call (stg_gc_fun)(R2, R1) args: 8, res: 0, upd: 8; }}} But in the calls that are made later on inside the function we do put some parameters on the stack, thus increasing stack usage: {{{ cFv: // not enough heap, call GC HpAlloc = 16; I64[Sp - 16] = cFn; R1 = _sEV::I64; I64[Sp - 8] = _sEU::I64; Sp = Sp - 16; call stg_gc_unbx_r1(R1) returns to cFn, args: 8, res: 8, upd: 8; }}} If we had more specialized entries to GC that would allow us to pass parameters in registers (or in some fixed memory location associated with TCO?) then this function would not require any stack at all. Note that there is a separate issue here - `_sEV` variable is in fact dead and should be eliminated (see #8327). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8335> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #6077: Respect XDG_CONFIG_HOME
by GHC 06 Oct '15

06 Oct '15

#6077: Respect XDG_CONFIG_HOME -------------------------------------+------------------------------------- Reporter: So8res | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: None | Version: 7.4.1 Resolution: | Keywords: Operating System: Linux | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 5966 | Blocking: Related Tickets: | Differential Rev(s): -------------------------------------+------------------------------------- Comment (by hvr): for the record, `directory` now has separate functions availabel for querying XDG dirs. So GHC now needs to decide if and how to support XDG base dirs -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/6077#comment:4> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5966: getAppUserDataDirectory does not respect XDG specification
by GHC 06 Oct '15

06 Oct '15

#5966: getAppUserDataDirectory does not respect XDG specification -------------------------------------+------------------------------------- Reporter: ordcoder | Owner: Type: bug | Status: closed Priority: normal | Milestone: 8.0.1 Component: Core Libraries | Version: 7.4.1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: 6077 Related Tickets: | Differential Rev(s): -------------------------------------+------------------------------------- Changes (by hvr): * status: new => closed * resolution: => fixed Comment: Replying to [comment:14 dolio]: > If the reason it's open is GHC placing its files in XDG directories, that is #6077 as mentioned by simonmar above. you're right... I missed that -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5966#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7411: Exceptions are optimized away in certain situations
by GHC 06 Oct '15

06 Oct '15

#7411: Exceptions are optimized away in certain situations -------------------------------------+------------------------------------- Reporter: SimonHengel | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 7.6.1 Resolution: | Keywords: seq, deepseq, | evaluate, exceptions Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: Incorrect result | Test Case: at runtime | simplCore/should_fail/T7411 Blocked By: | Blocking: Related Tickets: #5129 | Differential Rev(s): -------------------------------------+------------------------------------- Changes (by bgamari): * testcase: => simplCore/should_fail/T7411 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7411#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5966: getAppUserDataDirectory does not respect XDG specification
by GHC 06 Oct '15

06 Oct '15

#5966: getAppUserDataDirectory does not respect XDG specification -------------------------------------+------------------------------------- Reporter: ordcoder | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Core Libraries | Version: 7.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: 6077 Related Tickets: | Differential Rev(s): -------------------------------------+------------------------------------- Comment (by dolio): Isn't this still a report about `directory`? I think it was decided for the upstream issue that changing the behavior of `getAppUserDataDirectory` would silently break things, so it was better to add the XDG querying functions for people to use rather than switch this function. So should this issue be closed? If the reason it's open is GHC placing its files in XDG directories, that is #6077 as mentioned by simonmar above. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5966#comment:14> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5966: getAppUserDataDirectory does not respect XDG specification
by GHC 06 Oct '15

06 Oct '15

#5966: getAppUserDataDirectory does not respect XDG specification -------------------------------------+------------------------------------- Reporter: ordcoder | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Core Libraries | Version: 7.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: 6077 Related Tickets: | Differential Rev(s): -------------------------------------+------------------------------------- Changes (by hvr): * status: upstream => new * cc: ekmett (added) Comment: `directory` now provides primitives to query XDG dirs, so now the ball is again in GHC's court to decide how/whether to support XDG dirs. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5966#comment:13> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1407: Add the ability to :set -l{foo} in .ghci files
by GHC 06 Oct '15

06 Oct '15

#1407: Add the ability to :set -l{foo} in .ghci files -------------------------------------+------------------------------------- Reporter: guest | Owner: archblob Type: feature request | Status: merge Priority: normal | Milestone: 7.10.3 Component: GHCi | Version: 6.6.1 Resolution: | Keywords: Operating System: Windows | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D194 | Phab:D1310 -------------------------------------+------------------------------------- Changes (by simonmar): * status: patch => merge -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1407#comment:29> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10516: PolyKinds results in incorrect reporting of type synonym parameter count
by GHC 06 Oct '15

06 Oct '15

#10516: PolyKinds results in incorrect reporting of type synonym parameter count -------------------------------------+------------------------------------- Reporter: | Owner: benjamin.hodgson | Status: new Type: bug | Milestone: Priority: normal | Version: 7.8.3 Component: Compiler | Operating System: MacOS X Keywords: | Type of failure: None/Unknown Architecture: x86_64 | Blocked By: (amd64) | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The following program is invalid because the declaration of `f` doesn't fully apply `App` to all of its arguments. {{{#!hs {-# LANGUAGE PolyKinds #-} type App f a = f a newtype X f a = X (f a) f :: f a -> X (App f) a f = X }}} However, with the `PolyKinds` extension, the error reporting is quite weird: {{{ Type synonym ‘App’ should have 4 arguments, but has been given 3 In the type signature for ‘f’: f :: f a -> X (App f) a }}} `App` has ''two'' arguments, and I gave it ''one''! I'm guessing that `PolyKinds` makes GHC supply some implicit parameters during expansion of type synonyms, and that's what gets reported in the error message. The behaviour is correct without `PolyKinds`. I've tested this on GHC 7.8.3 (the Haskell Platform version). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10516> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4505: Segmentation fault on long input (list of pairs)
by GHC 06 Oct '15

06 Oct '15

#4505: Segmentation fault on long input (list of pairs) -------------------------------------+------------------------------------- Reporter: cathper | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 7.0.1 Resolution: | Keywords: Segmentation | fault, segfault, long input Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: Runtime crash | Test Case: Blocked By: 4258 | Blocking: Related Tickets: | Differential Rev(s): Phab:D1180 -------------------------------------+------------------------------------- Changes (by bgamari): * owner: bgamari => Comment: I fixed the compile-time check; leaving the proper RTS fix for someone else. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4505#comment:41> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8920: Alternative GADT syntax
by GHC 05 Oct '15

05 Oct '15

#8920: Alternative GADT syntax ----------------------------------------------+---------------------------- Reporter: guest | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler (Parser) | Version: Keywords: gadts | 7.8.1-rc2 Architecture: Unknown/Multiple | Operating System: Difficulty: Moderate (less than a day) | Unknown/Multiple Blocked By: | Type of failure: Other Related Tickets: | Test Case: | Blocking: ----------------------------------------------+---------------------------- An alternative syntax for GADTs Instead of {{{ data Term x where K :: Term (a -> b -> a) S :: Term ((a -> b -> c) -> (a -> b) -> a -> c) Const :: a -> Term a (:@) :: Term (a -> b) -> (Term a) -> Term b }}} You can write {{{ data Term x = K :: Term (a -> b -> a) | S :: Term ((a -> b -> c) -> (a -> b) -> a -> c) | Const a :: Term a | (:@) (Term (a -> b)) (Term a) :: Term b }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8920> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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