#12205: Program develops space leak with -fprof-auto -------------------------------------+------------------------------------- Reporter: kristenk | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Profiling | Version: 7.4.2 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: -------------------------------------+------------------------------------- This program seems to use constant memory when compiled with only `-prof`, but it uses increasing amounts of memory when compiled with `-prof` and `-fprof-auto`. I observed the behavior with GHC 8.0.1, 7.10.3, 7.8.4, 7.6.3, and 7.4.2, but not 7.0.4 (with `-auto-all`). {{{#!hs import System.Environment main :: IO () main = do n <- (read . head) `fmap` getArgs case f [0..(n::Int)] 0 of (xs, s) -> print xs >> print s f :: [Int] -> Int -> ([Int], Int) f [] s = ([], s) f (x:xs) s = let (xs', s') = f xs (x + s) in (x + s : xs', s') }}} {{{ $ ghc --version The Glorious Glasgow Haskell Compilation System, version 8.0.1 $ ghc Main.hs -prof [1 of 1] Compiling Main ( Main.hs, Main.o ) Linking Main ... $ /run/current-system/sw/bin/time ./Main 5000000 > /dev/null 2.80user 0.01system 0:02.82elapsed 100%CPU (0avgtext+0avgdata 6028maxresident)k 0inputs+0outputs (0major+661minor)pagefaults 0swaps }}} {{{ $ ghc Main.hs -prof -fprof-auto [1 of 1] Compiling Main ( Main.hs, Main.o ) Linking Main ... $ /run/current-system/sw/bin/time ./Main 5000000 > /dev/null 4.03user 0.35system 0:04.38elapsed 100%CPU (0avgtext+0avgdata 1574348maxresident)k 0inputs+0outputs (0major+392857minor)pagefaults 0swaps }}} [[Image(no-fprof-auto.png)]] [[Image(fprof-auto.png)]] -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12205 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler