• Simon Marlow's avatar
    Add -fghci-leak-check to check for space leaks · 5fe6aaa3
    Simon Marlow authored
    Space leaks in GHCi emerge from time to time and tend to come back again
    after they get fixed. This is an attempt to limit regressions by
    * adding a reliable detection for some classes of space leaks in GHCi
    * turning on leak checking for all GHCi tests in the test suite, so that
      we'll notice if the leak appears again.
    The idea for detecting space leaks is quite simple:
    * find some data that we expect to be GC'd later, make a weak pointer to it
    * when we expect the data to be dead, do a `performGC` and then check
      the status of the weak pointer.
    It would be nice to apply this trick to lots of things in GHC,
    e.g. ensuring that HsSyn is not retained after the desugarer, or
    ensuring that CoreSyn from the previous simplifier pass is not retained.
    Test Plan: validate
    Reviewers: bgamari, simonpj, erikd, niteria
    Subscribers: thomie, carter
    GHC Trac Issues: #15111
    Differential Revision: https://phabricator.haskell.org/D4658
UI.hs 149 KB