March 2019 - ghc-tickets

[GHC] #16271: Building stage1:lib:text target is not robust
by GHC 04 Mar '19

04 Mar '19

#16271: Building stage1:lib:text target is not robust -------------------------------------+------------------------------------- Reporter: mpickering | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.6.3 (Hadrian) | 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: -------------------------------------+------------------------------------- It seems the dependency on `cabal_macros.h` is not properly specified in the logic to build the libraries. If I start a build, build a library and then remove the library dir, the target fails to build. {{{ ./hadrian/build.sh stage1:lib:text rm -r _build/stage1/ ./hadrian/build.sh stage1:lib:text }}} {{{ cc1: fatal error: integersimple/stage1/libraries/text/build/autogen/cabal_macros.h: No such file or directory compilation terminated. `cc' failed in phase `C pre-processor'. (Exit code: 1) shakeArgsWith 0.000s 0% Function shake 0.006s 0% Database read 0.831s 23% ======== With database 0.100s 2% Running rules 2.545s 73% ========================= Total 3.482s 100% Error when running Shake build system: at src/Main.hs:58:30-42: * Depends on: stage1:lib:text at src/Rules/SimpleTargets.hs:31:5-15: * Depends on: integersimple/stage1/lib/package.conf.d/text-1.2.3.1.conf * Depends on: integersimple/stage1/libraries/text/build/libHStext-1.2.3.1.a * Depends on: integersimple/stage1/libraries/text/build/Data/Text/Show.o * Depends on: OracleQ (KeyValues ("integersimple/stage1/libraries/text/.dependencies","integersimple/stage1/libraries/text/build/Data/Text/Show.o")) * Depends on: integersimple/stage1/libraries/text/.dependencies * Depends on: integersimple/stage1/libraries/text/.dependencies.mk * Raised the exception: user error (Development.Shake.cmd, system command failed Command: integersimple/stage0/bin/ghc -M -hisuf hi -osuf o -hcsuf hc -static -hide-all-packages -no-user-package-db '-package-db integersimple/stage1/lib/package.conf.d' '-this-unit-id text-1.2.3.1' '-package-id array-0.5.2.0' '-package-id base-4.12.0.0' '-package-id binary-0.8.6.0' '-package-id bytestring-0.10.9.0' '-package-id deepseq-1.4.4.0' '-package-id ghc-prim-0.5.3' '-package-id integer- simple-0.1.1.1' -i -iintegersimple/stage1/libraries/text/build -iintegersimple/stage1/libraries/text/build/autogen -ilibraries/text/. -Iincludes -Iintegersimple/generated -Iintegersimple/stage1/libraries/text/build -I/nix/store /f97ls1qx6vxf75304874843ysdcyimnn-ghc-build-environment/include -Iintegersimple/stage1/libraries/text/build/include -Ilibraries/text/include -I/root/ghc/integersimple/stage1/lib/x86_64 -linux-ghc-8.7.20190124/bytestring-0.10.9.0/include -I/root/ghc/integersimple/stage1/lib/x86_64-linux- ghc-8.7.20190124/base-4.12.0.0/include -I/root/ghc/integersimple/stage1/lib/x86_64-linux- ghc-8.7.20190124/rts-1.0/include -Iintegersimple/generated -optc- Iintegersimple/generated -optP-include -optPintegersimple/stage1/libraries/text/build/autogen/cabal_macros.h -optP-DINTEGER_SIMPLE -outputdir integersimple/stage1/libraries/text/build -include-pkg-deps -dep-makefile integersimple/stage1/libraries/text/.dependencies.mk -dep-suffix '' -dep- suffix dyn_ libraries/text/Data/Text.hs libraries/text/Data/Text/Array.hs libraries/text/Data/Text/Encoding.hs libraries/text/Data/Text/Encoding/Error.hs libraries/text/Data/Text/Foreign.hs libraries/text/Data/Text/IO.hs libraries/text/Data/Text/Internal.hs libraries/text/Data/Text/Internal/Builder.hs libraries/text/Data/Text/Internal/Builder/Functions.hs libraries/text/Data/Text/Internal/Builder/Int/Digits.hs libraries/text/Data/Text/Internal/Builder/RealFloat/Functions.hs libraries/text/Data/Text/Internal/Encoding/Fusion.hs libraries/text/Data/Text/Internal/Encoding/Fusion/Common.hs libraries/text/Data/Text/Internal/Encoding/Utf16.hs libraries/text/Data/Text/Internal/Encoding/Utf32.hs libraries/text/Data/Text/Internal/Encoding/Utf8.hs libraries/text/Data/Text/Internal/Functions.hs libraries/text/Data/Text/Internal/Fusion.hs libraries/text/Data/Text/Internal/Fusion/CaseMapping.hs libraries/text/Data/Text/Internal/Fusion/Common.hs libraries/text/Data/Text/Internal/Fusion/Size.hs libraries/text/Data/Text/Internal/Fusion/Types.hs libraries/text/Data/Text/Internal/IO.hs libraries/text/Data/Text/Internal/Lazy.hs libraries/text/Data/Text/Internal/Lazy/Encoding/Fusion.hs libraries/text/Data/Text/Internal/Lazy/Fusion.hs libraries/text/Data/Text/Internal/Lazy/Search.hs libraries/text/Data/Text/Internal/Private.hs libraries/text/Data/Text/Internal/Read.hs libraries/text/Data/Text/Internal/Search.hs libraries/text/Data/Text/Internal/Unsafe.hs libraries/text/Data/Text/Internal/Unsafe/Char.hs libraries/text/Data/Text/Internal/Unsafe/Shift.hs libraries/text/Data/Text/Lazy.hs libraries/text/Data/Text/Lazy/Builder.hs libraries/text/Data/Text/Lazy/Builder/Int.hs libraries/text/Data/Text/Lazy/Builder/RealFloat.hs libraries/text/Data/Text/Lazy/Encoding.hs libraries/text/Data/Text/Lazy/IO.hs libraries/text/Data/Text/Lazy/Internal.hs libraries/text/Data/Text/Lazy/Read.hs libraries/text/Data/Text/Read.hs libraries/text/Data/Text/Show.hs libraries/text/Data/Text/Unsafe.hs -O0 -H64m -Wall -fwarn-tabs -funbox-strict-fields -O2 -XHaskell98 -ghcversion- file=/root/ghc/integersimple/generated/ghcversion.h -O -Wno-deprecated- flags -Wno-unused-imports -Werror Exit code: 1 Stderr: cc1: fatal error: integersimple/stage1/libraries/text/build/autogen/cabal_macros.h: No such file or directory compilation terminated. `cc' failed in phase `C pre-processor'. (Exit code: 1) ) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16271> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16339: Cannot put (.) or (!) into an export list
by GHC 04 Mar '19

04 Mar '19

#16339: Cannot put (.) or (!) into an export list -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Thanks to recent work in GHC HEAD, it is now possible to define type operators named `(.)` and `(!)`: {{{#!hs type (f . g) x = f (g x) type x ! f = f x }}} However, I was surprised to discover that it's not possible to put them in an export list! That is to say, this program doesn't parse: {{{ {-# LANGUAGE TypeOperators #-} module Bug (type (.), type (!)) where type (f . g) x = f (g x) type x ! f = f x }}} {{{ $ ~/Software/ghc4/inplace/bin/ghc-stage2 --interactive Bug.hs GHCi, version 8.7.20190219: https://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci Bug.hs:2:19: error: parse error on input ‘.’ | 2 | module Bug (type (.), type (!)) where | ^ }}} This problem appears to be specific to the `(.)` and `(!)` type operators, since any other type operator will work in its place: {{{#!hs {-# LANGUAGE TypeOperators #-} module Works (type (&)) where type (f & g) x = f (g x) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16339> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16348: GHC HEAD regression: tyConAppArgs
by GHC 04 Mar '19

04 Mar '19

#16348: GHC HEAD regression: tyConAppArgs -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The following program compiles (with `-O`) on GHC 7.0.4 through 8.6.3, but panics on HEAD: {{{#!hs {-# LANGUAGE DeriveFunctor #-} module Bug where data V2 a = V2 !a !a deriving Functor (*^) :: (Functor f, Num a) => a -> f a -> f a (*^) a = fmap (a*) (*!!) :: (Functor m, Functor r, Num a) => a -> m (r a) -> m (r a) s *!! m = fmap (s *^) m type M22 a = V2 (V2 a) det22 :: Num a => M22 a -> a det22 (V2 (V2 a b) (V2 c d)) = a * d - b * c inv22 :: Fractional a => M22 a -> M22 a inv22 m@(V2 (V2 a b) (V2 c d)) = (1 / det) *!! V2 (V2 d (-b)) (V2 (-c) a) where det = det22 m }}} {{{ $ ~/Software/ghc4/inplace/bin/ghc-stage2 -fforce-recomp Bug.hs -O [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.7.20190219 for x86_64-unknown-linux): tyConAppArgs a_a1FK Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1159:37 in ghc:Outputable pprPanic, called at compiler/types/Type.hs:1183:50 in ghc:Type }}} Note that this panic does not occur if `V2` is defined without `!`s. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16348> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15952: Reduce zonking-related invariants in the type checker
by GHC 04 Mar '19

04 Mar '19

#15952: Reduce zonking-related invariants in the type checker -------------------------------------+------------------------------------- Reporter: goldfire | Owner: (none) Type: task | Status: new Priority: normal | Milestone: 8.6.3 Component: Compiler | Version: 8.6.2 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: -------------------------------------+------------------------------------- The type checker currently maintains two invariants, documented in `Note [The well-kinded type invariant]` in TcType and `Note [The tcType invariant]` in TcHsType. These are a pain to maintain, and Simon and I cooked up a plan not to. Step 1. The tcType invariant is all about `tcInferApps`, at least according to the Note. Previously, we couldn't zonk in `tcInferApps`, because types were knot-tied. But now we can! So, `tcInferApps` could take the type only (not its kind), zonk it, then get the type's (zonked) kind. This might also mean that `tc_infer_hs_type` no longer needs to return a type/kind pair, but could just return a type. After this is done, we can likely remove all the zonks that are in service to the tcType invariant, findable by a search. Step 2. The well-kinded type invariant is also about the need to zonk sometimes. But, instead, we could just always zonk on-the-fly. That is, we introduce new functions like `tcTypeKind` and `tcSubstTy` that zonk as they go. To make sure we're calling the right function at the right time, we introduce `newtype TcType = TcType { unTcType :: Type }`. Then, we're forced to call monadic functions on `TcType`s. This will likely lead to code duplication between `Type` and `TcType`, but we might be able to banish `zonkTcType` (and its many friends) entirely. Also gone would be the `naked` functions, which are all about maintaining the well-kinded type invariant. This step would, as a side effect, fix #15799 and #15918, which is about treating `TcType`s differently from `Type`s. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15952> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16258: PowerPC Big-Endian: ArithInt16, ArithInt8, ArithWord16, and ArithWord8 fail
by GHC 04 Mar '19

04 Mar '19

#16258: PowerPC Big-Endian: ArithInt16, ArithInt8, ArithWord16, and ArithWord8 fail -------------------------------------+------------------------------------- Reporter: trommler | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.10.1 Component: Compiler | Version: 8.7 Keywords: Big-endian | Operating System: Unknown/Multiple Architecture: powerpc64 | Type of failure: Incorrect result Test Case: | at runtime primops/should_run/ArithInt16, | Blocked By: primops/should_run/ArithWord16, | primops/should_run/ArithWord8, | primops/should_run/ArithInt8 | Blocking: | Related Tickets: #16222 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The tests were run on a PowerMac G5 running Linux, PowerMacs are big- endian. I reduced the issue to this program where I get the incorrect answer `25132`: {{{#!hs {-# LANGUAGE BangPatterns #-} {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} module Main where import GHC.Exts main :: IO () main = do putStrLn $ show (apply2 plusInt16# (50) (50)) apply2 :: (Int16# -> Int16# -> Int16#) -> Int -> Int -> Int apply2 op (I# a) (I# b) = let (# sa, sb #) = (# narrowInt16# a, narrowInt16# b #) r = op sa sb in I# (extendInt16# r) {-# NOINLINE apply2 #-} }}} Curiously, when I inline `plusInt16#` and remove the op parameter the result is correct. The test passes on little-endian PowerPC 64-bit. Note: This is bug is different form #16222 that deals with the C calling convention. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16258> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16077: AvailTC Invariant being violated
by GHC 04 Mar '19

04 Mar '19

#16077: AvailTC Invariant being violated -------------------------------------+------------------------------------- Reporter: harpocrates | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 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: -------------------------------------+------------------------------------- The `AvailTC Invariant` (from `basicTypes/Avail.hs`) states that: {{{ If the type or class is itself to be in scope, it must be *first* in this list. Thus, typically: @AvailTC Eq [Eq, ==, \/=]@ }}} Here is a case where this invariant is not upheld: * `pkgA/pkgA.cabal`: {{{ name: pkgA version: 1.0.0 build-type: Simple cabal-version: >= 1.2 library exposed-modules: A build-depends: base }}} * `pkgA/A.hs` {{{ {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeFamilies #-} module A ( C(..) , T(TI) , error ) where class C a where data T a instance C Int where data T Int = TI { ti :: Int } }}} * `pkgB/pkgB.cabal` {{{ name: pkgB version: 1.0.0 build-type: Simple cabal-version: >= 1.2 library exposed-modules: B build-depends: base, pkgA }}} * `pkgB/B.hs` {{{ module B ( module A ) where import A hiding (error) }}} Now, check out the exports for `A` vs. `B`: {{{ $ cabal new-build pkgA pkgB --ghc-options -ddump-rn-trace | grep rnExports Warning: The package list for 'hackage.haskell.org' is 38 days old. Run 'cabal update' to get the latest list of available packages. rnExports: Exports: [error, C{C, T;}, T{T, TI;}] rnExports: Exports: [C{C, T;}, T{TI;}] }}} Why is `T{TI;}` in the second line not `T{T, TI;}`? Shouldn't the exports for `B` be identical to those for `A` (except for `error`)? This is causing a crash in Haddock: https://github.com/haskell/haddock/issues/979. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16077> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16288: Core Lint error: Occurrence is GlobalId, but binding is LocalId
by GHC 04 Mar '19

04 Mar '19

#16288: Core Lint error: Occurrence is GlobalId, but binding is LocalId -------------------------------------+------------------------------------- Reporter: monoidal | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: 15840 | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Compiling the following three modules causes a Core Lint error in HEAD. (This does not happen in 8.6 - the Lint check was introduced later.) To reproduce: save the three files in `Repro/` directory and use `ghc- stage2 -dcore-lint -O Repro/B.hs`. The reproduction code is minimized version of code from cabal and prettyprint libraries. A.hs {{{ #!haskell module Repro.A where import Repro.C data License class Pretty a where pretty :: a -> Doc instance Pretty License where pretty _ = pretV bar :: (Pretty a) => a -> Doc bar w = foo (pretty (u w w w w)) u :: a -> a -> a -> a -> a u = u }}} B.hs {{{ #!haskell module Repro.B where import Repro.A import Repro.C bar2 :: License -> Doc bar2 = bar }}} C.hs {{{ #!haskell module Repro.C where data Doc = Empty | Beside Doc hcat :: Doc -> Doc hcat Empty = Empty hcat xs = hcat xs pretV = hcat Empty foo :: Doc -> Doc foo Empty = hcat Empty foo val = Beside val }}} The error: {{{ *** Core Lint errors : in result of Simplifier *** Repro/C.hs:9:1: warning: [in body of letrec with binders pretV_r3 :: Doc] Occurrence is GlobalId, but binding is LocalId pretV :: Doc [GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 20 0}] *** Offending Program *** lvl_s1kN :: Doc [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=True, Expandable=False, Guidance=IF_ARGS [] 30 20}] lvl_s1kN = case pretV of wild_Xd { Empty -> pretV; Beside ipv_s105 -> Beside wild_Xd } $sbar_s1kL [InlPrag=NOUSERINLINE[2]] :: License -> Doc [LclId, Arity=1, Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True) Tmpl= \ _ [Occ=Dead] -> case pretV of wild_Xd [Occ=Once*] { Empty -> let { pretV_r3 :: Doc [LclId] pretV_r3 = wild_Xd } in pretV; Beside _ [Occ=Dead] -> Beside wild_Xd }}] $sbar_s1kL = \ _ [Occ=Dead] -> lvl_s1kN $trModule_s1kE :: Addr# [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}] $trModule_s1kE = "main"# $trModule_s1kF :: TrName [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 20}] $trModule_s1kF = TrNameS $trModule_s1kE $trModule_s1kG :: Addr# [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}] $trModule_s1kG = "Repro.B"# $trModule_s1kH :: TrName [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 20}] $trModule_s1kH = TrNameS $trModule_s1kG $trModule :: Module [LclIdX, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 30}] $trModule = Module $trModule_s1kF $trModule_s1kH bar2 :: License -> Doc [LclIdX, Arity=1, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [0] 30 20}] bar2 = \ _ [Occ=Dead] -> case pretV of wild_Xd { Empty -> pretV; Beside ipv_s105 -> Beside wild_Xd } *** End of Offense *** }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16288> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16254: INLINABLE pragma and newtype wrappers prevent inlining
by GHC 04 Mar '19

04 Mar '19

#16254: INLINABLE pragma and newtype wrappers prevent inlining -------------------------------------+------------------------------------- Reporter: monoidal | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #5327 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In #5327, we allowed case-of-known constructor to see through bindings that were marked as INLINABLE and used newtypes. However, this works only if the newtype does not have a wrapper. The following code, which is the same as T5237 except for the extra type parameters in Size, does not cause the optimization to fire. {{{ {-# LANGUAGE GADTs, ExplicitForAll #-} module T16254 where newtype Size a b where Size :: forall b a. Int -> Size a b {-# INLINABLE val2 #-} val2 = Size 17 f n = case val2 of Size s -> s + s > n }}} The reason is that `exprIsConApp_maybe` sees `$WSize (I# 17#)`, which is an application with a nontrivial argument. In general, this could cause duplication of work, but in this case we're dealing with a newtype wrapper, so this is safe. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16254> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16272: libffi copies files into rts build tree
by GHC 04 Mar '19

04 Mar '19

#16272: libffi copies files into rts build tree -------------------------------------+------------------------------------- Reporter: mpickering | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.6.3 (Hadrian) | 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: -------------------------------------+------------------------------------- The `rts` should explicitly depend on `ffi.h` and `ffitarget.h`, then use this path to copy in these two header files itself rather than relying on the libffi build rule to copy them into the `rts/build` directory. You can see this happening in `Rules.Libffi.libffiRules` This often results in a failure where the `rts` rule will fail to produce these files after deleting build products in `_build`. {{{ shakeArgsWith 0.000s 0% Function shake 0.006s 0% Database read 1.051s 0% Database compression 0.146s 0% With database 0.031s 0% Running rules 121.010s 98% ========================= Total 122.244s 100% Error when running Shake build system: at src/Main.hs:58:30-42: * Depends on: stage1:lib:text at src/Rules/SimpleTargets.hs:31:5-15: * Depends on: integersimple/stage1/lib/package.conf.d/text-1.2.3.1.conf * Depends on: OracleQ (ContextDataKey (Context {stage = Stage1, package = Package {pkgType = Library, pkgName = "text", pkgPath = "libraries/text"}, way = v})) * Depends on: integersimple/stage1/libraries/text/setup-config * Depends on: integersimple/stage1/lib/package.conf.d/base-4.12.0.0.conf * Depends on: OracleQ (ContextDataKey (Context {stage = Stage1, package = Package {pkgType = Library, pkgName = "base", pkgPath = "libraries/base"}, way = v})) * Depends on: integersimple/stage1/libraries/base/setup-config * Depends on: integersimple/stage1/lib/package.conf.d/rts-1.0.conf * Depends on: integersimple/stage1/rts/build/libHSrts-1.0_thr_l.a * Depends on: integersimple/stage1/rts/build/c/Interpreter.thr_l_o * Depends on: integersimple/stage1/rts/build/ffi.h * Depends on: integersimple/stage1/rts/build/ffi.h integersimple/stage1/rts/build/ffitarget.h * Raised the exception: Error, &%> rule failed to produce 2 files (out of 2) integersimple/stage1/rts/build/ffi.h - MISSING integersimple/stage1/rts/build/ffitarget.h - MISSING CallStack (from HasCallStack): error, called at src/Development/Shake/Internal/Rules/Files.hs:245:13 in shake-0.17.2-586622e6ae1d899ec790b1028cae3413c00a616f124bac634769a9607581e631:Development.Shake.Internal.Rules.Files }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16272> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16295: Enable cached builds with Hadrian
by GHC 04 Mar '19

04 Mar '19

#16295: Enable cached builds with Hadrian -------------------------------------+------------------------------------- Reporter: snowleopard | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.6.3 (Hadrian) | 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: -------------------------------------+------------------------------------- As Neil is working on turning Shake into Cloud Shake [1], Shake has got a new feature of "locally cached builds", making it possible to reuse build artefacts from previous builds on the same machine. This means, in particular, that a clean build could be finished very quickly if you've built GHC before from the same/similar sources. Hopefully, this could also help us speed up GHC's CI some day. To enable cached builds, it is important to find and fix all instances of untracked dependencies in Hadrian, or at least record them using the `produces` feature of Shake [2], because otherwise Shake has no idea that these files are actually needed and should therefore be stored in the cache. Here are a couple of tickets related to untracked dependencies: https://ghc.haskell.org/trac/ghc/ticket/16271 https://ghc.haskell.org/trac/ghc/ticket/16272 I am currently working this and hope to produce a patch soon. [1] See the Build Systems à la Carte paper: https://dl.acm.org/ft_gateway.cfm?id=3236774 [2] http://hackage.haskell.org/package/shake/docs/Development- Shake.html#v:produces -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16295> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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