Re: [GHC] #15808: Loading libraries with FFI exports may cause segfaults in the compiler if they are loaded far from the rts in memory.

#15808: Loading libraries with FFI exports may cause segfaults in the compiler if they are loaded far from the rts in memory. -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 (Linking) | Resolution: | Keywords: Operating System: Windows | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by AndreasK): * priority: high => normal * owner: AndreasK => (none) Comment: Fixing this won't be easy, so for the moment I will leave it as is. The main issue is that we try to jump from a loaded library to the rts. Now we have the problem that we end up with a memory layout of something like this: <... 2+GB of things ...> <libraries loaded for TH> Fixing the C stubs was reasonably easy. We can just tell gcc to use the large memory model making jumps 64bit sized. What I had failed to consider is that we also jump into the rts from regular haskell code. Now making sure all THIS code works well with a 64 bit address space sounds bad enough. But it also comes with performance costs as we increase code size. Given, probably not a big one but still. So even IF we fix this we would incurr a performance penalty for pretty much ALL haskell programs out there. So this seems like it's not worth it at the moment unless there are somehow a lot of "random" crashes out there which can be traced back to this issue. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15808#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler