#13059: High memory usage during compilation -------------------------------------+------------------------------------- Reporter: domenkozar | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.2-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I've independently verified that 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060 caused this regression (at least on `Store-Random.hs`, which I believe is representative of `store`'s compilation regression as a whole). Furthermore, I discovered something interesting. I tweaked `StoreImpl.hs` and `Store-Random.hs` a little such that: 1. `StoreImpl.hs` no longer uses `DefaultSignatures` 2. `Store-Random.hs` now explicitly defines all of its instance methods. That is, `Store-Random.hs` contains these lines: {{{#!hs instance Store ModName instance Store Name instance Store NameFlavour instance Store Type instance Store TyVarBndr instance Store NameSpace instance Store PkgName instance Store OccName instance Store TyLit }}} I tweaked it to be this instead: {{{#!hs instance Store ModName where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store Name where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store NameFlavour where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store Type where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store TyVarBndr where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store NameSpace where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store PkgName where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store OccName where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} instance Store TyLit where size = genericSize peek = genericPeek poke = genericPoke {-# INLINE size #-} {-# INLINE peek #-} {-# INLINE poke #-} }}} I then ran `-dshow-passes` on this program using a pre- 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060 GHC and a post- 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060 GHC. On the original `Store-Random.hs` program: * Pre-54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060: {{{ *** Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store]: Result size of Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) = {terms: 12,859, types: 119,332, coercions: 72,859} !!! Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store]: finished in 236.00 milliseconds, allocated 252.916 megabytes *** Simplifier [Store]: Result size of Simplifier iteration=1 = {terms: 40,398, types: 205,815, coercions: 109,233} }}} * Post-54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060: {{{ *** Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store]: Result size of Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) = {terms: 12,859, types: 119,332, coercions: 72,859} !!! Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store]: finished in 160.00 milliseconds, allocated 252.680 megabytes *** Simplifier [Store]: Result size of Simplifier iteration=1 = {terms: 59,073, types: 286,228, coercions: 152,155} }}} On the tweaked `Store-Random.hs` program: * Pre-54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060: {{{ *** Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store2]: Result size of Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) = {terms: 12,796, types: 119,305, coercions: 72,832} !!! Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store2]: finished in 156.00 milliseconds, allocated 252.064 megabytes *** Simplifier [Store2]: Result size of Simplifier iteration=1 = {terms: 58,888, types: 283,015, coercions: 149,870} }}} * Post-54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060: {{{ *** Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store2]: Result size of Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) = {terms: 12,796, types: 119,305, coercions: 72,832} !!! Float out(FOS {Lam = Just 0, Consts = True, OverSatApps = False}) [Store2]: finished in 176.00 milliseconds, al located 252.076 megabytes *** Simplifier [Store2]: Result size of Simplifier iteration=1 = {terms: 58,888, types: 283,015, coercions: 149,870} }}} Notice that in the tweaked `Store-Random.hs`, there is no difference before and after 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060. While this consistency is nice, the resulting program size is the same as the original program post-54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060, so this certainly didn't fix the bug—it just made it easier to see in the source program. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13059#comment:17 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler