[GHC] #9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow)
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: hour) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Found by ./validate: '''testsuite/tests/rts/overflow1.hs''' SIGSEGVs due to integer overflow somewhere around [https://git.haskell.org/ghc.git/blob/c88559b3304cc5e142ab9c2655d48e570f81afe... shouldInlinePrimOp] {{{#!hs ... shouldInlinePrimOp dflags NewByteArrayOp_Char [(CmmLit (CmmInt n _))] | fromInteger n <= maxInlineAllocSize dflags = ... }}} '''maxInlineAllocSize''' has ''':: Int''' type: {{{#!hs fromInteger (2^64 - 10) < (128 :: Int) True }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by slyfox): * owner: => tibbe -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by tibbe): I'm working on it. Turns out that trying to fix this exposes all of ours sins i.e. all the places where we use `Int` where we should have used `Word`, for example in `wordsToBytes` and perhaps `ByteOff`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by tibbe): It looks like the overflow isn't in `shouldInlinePrimOp` (although that function should be fixed too) but in the code that create the `CmmInt` literal. Adding this tracing {{{ shouldInlinePrimOp dflags NewByteArrayOp_Char [(CmmLit (CmmInt n _))] | n <= fromIntegral (maxInlineAllocSize dflags) = trace ("matches " ++ show n) $ }}} shows that `n` is -40, even thought it's an Integer, suggesting that the wrap-around happened elsewhere. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by tibbe): The core confirms my suspicions: {{{ case GHC.Prim.newByteArray# @ GHC.Prim.RealWorld (-40) s1_a1Cc }}} The only workaround I can think of is quite unpleasant. We need to cast the `Integer` in the `CmmInt` to a `Word`(and then perhaps back to an `Integer`) to get rid of the 2-complement interpretation of the value. The real fix is to change `newByteArray#` to take the size as a `Word#`. I don't see how the overflow1 test ever passed. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by tibbe): If we disable `shouldInlinePrimOp` altogether we get this Cmm: {{{ R1 = (-40); Sp = Sp - 8; call stg_newByteArray#(R1) returns to c3Nu, args: 8, res: 8, upd: 8; }}} Presumably `stg_newByteArrayzh` interprets its argument as an unsigned quantity and thus the test passes without `shouldInlinePrimOp`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: D128 | -------------------------------------+------------------------------------- Changes (by tibbe): * status: new => patch * differential: => D128 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: D128 | -------------------------------------+------------------------------------- Comment (by carter): is the Int/word issue related to https://ghc.haskell.org/trac/ghc/ticket/8299 ? (ie because we don't have the richer distinction between how we use ints and words for address manipulation?) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on
./validate --slow)
-------------------------------------+-------------------------------------
Reporter: slyfox | Owner: tibbe
Type: bug | Status: patch
Priority: normal | Milestone:
Component: Compiler | Version: 7.8.3
Resolution: | Keywords:
Operating System: | Architecture: Unknown/Multiple
Unknown/Multiple | Difficulty: Easy (less than 1
Type of failure: | hour)
None/Unknown | Blocked By:
Test Case: | Related Tickets:
Blocking: |
Differential Revisions: D128 |
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Comment (by Johan Tibell
#9416: newArray# incorrectly inlines big arrays (overflow1.hs SIGSEGVS on ./validate --slow) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: tibbe Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: fixed | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: | hour) None/Unknown | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: D128 | -------------------------------------+------------------------------------- Changes (by tibbe): * status: patch => closed * resolution: => fixed -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9416#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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