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Re: [GHC] #5987: Too many symbols in ghc package DLL
by GHC 04 Aug '14

04 Aug '14

#5987: Too many symbols in ghc package DLL -------------------------------------+------------------------------------- Reporter: igloo | Owner: non-existant-user Type: bug | Status: new Priority: high | Milestone: 7.8.4 Component: Compiler | Version: 7.5 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: 3658 | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by thoughtpolice): * owner: thoughtpolice => non-existant-user -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5987#comment:36> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7858: Fix definitions of abs/signum for Floats/Doubles
by GHC 04 Aug '14

04 Aug '14

#7858: Fix definitions of abs/signum for Floats/Doubles -------------------------------------+------------------------------------- Reporter: lerkok | Owner: Type: bug | Status: patch Priority: normal | Milestone: 7.10.1 Component: | Version: 7.6.3 libraries/base | Keywords: floating point Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: #9238 None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by rwbarton): * milestone: => 7.10.1 Comment: We can replace the expensive `isNegativeZero x` test in `abs` with `x == 0`, since `abs` of positive zero is also zero. {{{ abs x | x == 0 = 0 | x >= 0 = x | otherwise = negate x }}} Of course this merits a comment on the first guard! As for `signum`, I don't see off-hand a simple way to work around the bug #9238, so I suggest we apply the `abs` patch, then mark this ticket as blocked by #9238. If someone gets around to implementing efficient `abs` and `signum` with fancy bit tricks before 7.10 then it will become moot anyway. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7858#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7858: Fix definitions of abs/signum for Floats/Doubles
by GHC 04 Aug '14

04 Aug '14

#7858: Fix definitions of abs/signum for Floats/Doubles -------------------------------------+------------------------------------- Reporter: lerkok | Owner: Type: bug | Status: patch Priority: normal | Milestone: Component: | Version: 7.6.3 libraries/base | Keywords: floating point Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: #9238 None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by rwbarton): * related: => #9238 Comment: Oh I know why. See #9238. `signum` looks something like {{{ \(D# x) -> case x of { __DEFAULT__ -> ... 0.0 -> x } }}} and at `-O1` and higher, `x` is inlined to `0` in the right-hand side of the second case alternative. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7858#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7858: Fix definitions of abs/signum for Floats/Doubles
by GHC 04 Aug '14

04 Aug '14

#7858: Fix definitions of abs/signum for Floats/Doubles -------------------------------------+------------------------------------- Reporter: lerkok | Owner: Type: bug | Status: patch Priority: normal | Milestone: Component: | Version: 7.6.3 libraries/base | Keywords: floating point Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by thoughtpolice): I'm taking a look at these patches now to see if I can figure out the issue with the first one. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7858#comment:4> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9379: Blocked STM transaction is not interruptible
by GHC 04 Aug '14

04 Aug '14

#9379: Blocked STM transaction is not interruptible -------------------------------------+------------------------------------- Reporter: Feuerbach | Owner: simonmar Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- {{{#!hs import Control.Exception import Control.Concurrent import Control.Concurrent.STM import Foreign.StablePtr main :: IO () main = do tv <- atomically $ newTVar True _ <- newStablePtr tv t <- mask_ $ forkIO (blockSTM tv) killThread t blockSTM :: TVar Bool -> IO () blockSTM tv = do atomically $ do v <- readTVar tv check $ not v }}} This code blocks forever. As I understand it, since the transaction blocks, it should be interruptible even despite the mask, and so killThread must succeed here, and the program should finish promptly. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9379> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9329: GHC panics when Cmm-compiling `STK_CHK_GEN_N (8);`
by GHC 04 Aug '14

04 Aug '14

#9329: GHC panics when Cmm-compiling `STK_CHK_GEN_N (8);` -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.8.3 Keywords: | Differential Revisions: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- The following Cmm code snippet compiles fine {{{#!c foo () { STK_CHK_GEN_N (((1)*8)); /* works */ return (0); } }}} The following one, however, only compiles with `-O0`, but panics with `-O1` or more: {{{#!c foo () { STK_CHK_GEN_N (8); /* panics */ return (0); } }}} {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.8.3 for x86_64-unknown-linux): bundle c1 foo [(c1, label: block{v c1}_info rep:StackRep [])] [(c0, {}), (c3, {})] foo() // [] { info_tbl: [(c1, label: block{v c1}_info rep:StackRep [])] stack_info: arg_space: 8 updfr_space: Just 8 } {offset c0: R1 = 0; call (P64[Sp])(R1) args: 8, res: 0, upd: 8; } } Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9329> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9303: O2: (GHC version 7.8.3 for x86_64-unknown-linux): allocateRegsAndSpill: Cannot read from uninitialized register %vI_s1Mp
by GHC 04 Aug '14

04 Aug '14

#9303: O2: (GHC version 7.8.3 for x86_64-unknown-linux): allocateRegsAndSpill: Cannot read from uninitialized register %vI_s1Mp ----------------------------------+--------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (NCG) | Version: 7.8.3 Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 (amd64) | Type of failure: Compile-time crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+--------------------------------------- {{{ ghc --make -O2 M.hs [1 of 1] Compiling M ( M.hs, M.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.8.3 for x86_64-unknown-linux): allocateRegsAndSpill: Cannot read from uninitialized register %vI_s1Mp Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} As in #9155 bug was caught on '''wx''' package in the same module. I didn't try to trim it down to minimal sample. No external modules required. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9303> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9403: Make --show-iface more human readable
by GHC 04 Aug '14

04 Aug '14

#9403: Make --show-iface more human readable -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: task | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Other Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Right now --show-iface is not particularly interpretable, even if you are looking at the Outputable instance for `ModIface`. The problem seems to be the output for `mi_deps`, `mi_usages`, `mi_decls`, `mi_insts`, `mi_fam_insts` and `mi_rules` is not clearly delimited, making it unclear (for example) what `import -/ base:Prelude HASH` refers to unless you already happen to know that this must be from `mi_usages`. It should be relatively easy to improve this, but I want to make sure people who rely on this output aren't blindsided by the changes. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9403> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #9401: MVar deadlock exceptions cause exceptions in later MVar ops
by GHC 04 Aug '14

04 Aug '14

#9401: MVar deadlock exceptions cause exceptions in later MVar ops -------------------------------------+------------------------------------- Reporter: snoyberg | Owner: simonmar Type: bug | Status: closed Priority: normal | Milestone: Component: Runtime | Version: 7.8.2 System | Keywords: Resolution: invalid | Architecture: x86_64 (amd64) Operating System: Linux | Difficulty: Unknown Type of failure: Incorrect | Blocked By: result at runtime | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by simonmar): * status: new => closed * resolution: => invalid Comment: This isn't a bug. There are two threads: the main thread, blocked in readMVar, and the child thread, blocked in takeMVar. BOTH threads are deadlocked, so the RTS sends them both an exception. It has no way to tell that unblocking the child thread would later allow the main thread to make progress, or indeed whether the reverse might be true. So the rule is simple: when there are a group of deadlocked threads, they are all sent an exception simultaneously. There's a similar example in my book, [http://chimera.labs.oreilly.com/books/1230000000929/ch15.html#sec_deadlock] see `deadlock1.hs`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9401#comment:1> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7662: Improve GC of mutable objects
by GHC 03 Aug '14

03 Aug '14

#7662: Improve GC of mutable objects -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: feature | Status: new request | Milestone: ⊥ Priority: normal | Version: 7.7 Component: Runtime | Keywords: System | Architecture: Unknown/Multiple Resolution: | Difficulty: Unknown Operating System: | Blocked By: Unknown/Multiple | Related Tickets: Type of failure: | None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by ihameed): * cc: idhameed@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7662#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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