#14972: MacOS panic on TH -------------------------------------+------------------------------------- Reporter: harpocrates | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by ezyang): I've diagnosed the proximate cause. In the failing version of the compiler, an inplace build creates a `gmp` directory in `libraries /integer-gmp/dist-install/build/`: {{{ MacBook-Pro-97:ghc-quick1 ezyang$ ls libraries/integer-gmp/dist- install/build/ GHC gmp HSinteger-gmp-1.0.1.0.o include autogen integer-gmp.buildinfo cbits libHSinteger- gmp-1.0.1.0-ghc8.5.20180331.dylib config.log libHSinteger-gmp-1.0.1.0.a config.status }}} Unfortuantely, this changes the behavior of our print file name invocation: {{{ MacBook-Pro-97:ghc-quick1 ezyang$ gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -B/Users/ezyang/Dev/ghc-quick1/libraries/integer-gmp /dist-install/build --print-file-name gmp /Users/ezyang/Dev/ghc-quick1/libraries/integer-gmp/dist-install/build/gmp }}} This should return `gmp`. When it returns a file path, we attempt to open this location, which clearly will not work: {{{ *** gcc: gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -B/Users/ezyang/Dev/ghc- quick1/libraries/integer-gmp/dist-install/build --print-file-name gmp addLibrarySearchPath: dll_path = `/Users/ezyang/Dev/ghc-quick1/libraries /integer-gmp/dist-install/build' Loading package integer-gmp-1.0.1.0 ... addDLL: dll_name = '/Users/ezyang/Dev/ghc-quick1/libraries/integer-gmp/dist-install/build /libHSinteger-gmp-1.0.1.0-ghc8.5.20180331.dylib' internal_dlopen: dll_name = '/Users/ezyang/Dev/ghc-quick1/libraries /integer-gmp/dist-install/build/libHSinteger- gmp-1.0.1.0-ghc8.5.20180331.dylib' loadArchive: start loadArchive: Loading archive `/Users/ezyang/Dev/ghc-quick1/libraries /integer-gmp/dist-install/build/gmp' ghc-stage2: loadArchive: Failed reading header from `/Users/ezyang/Dev /ghc-quick1/libraries/integer-gmp/dist-install/build/gmp' loadArchive: done *** Deleting temp files: Deleting: *** Deleting temp dirs: Deleting: ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.5.20180331 for x86_64-apple-darwin): loadArchive "/Users/ezyang/Dev/ghc-quick1/libraries/integer-gmp /dist-install/build/gmp": failed Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} I hazard some change in Cabal caused the 'gmp' directory to be created. Not entirely sure what the correct fix is yet. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14972#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler