[GHC] #13093: Runtime linker chokes on LLVM function on Windows

[GHC]

#13093: Runtime linker chokes on LLVM function on Windows
-------------------------------------+-------------------------------------
           Reporter:  RyanGlScott    |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.2.1
          Component:  Runtime        |           Version:  8.0.1
  System (Linker)                    |
           Keywords:                 |  Operating System:  Windows
       Architecture:                 |   Type of failure:  GHCi crash
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 This error prevents the [http://hackage.haskell.org/package/llvm-general
 llvm-general] library from loading in GHCi on Windows. I don't know how to
 reproduce this error without using LLVM.

 First, you need to install LLVM. On Windows, you can install it with
 MSYS2:

 {{{
 pacman -S mingw-w64-x86_64-llvm
 }}}

 Currently, this gives you LLVM-3.9, although I've reproduced it with
 LLVM-3.8 as well.

 Now define this Haskell file:

 {{{#!hs
 module Main (main) where

 import Foreign.C.Types

 newtype LLVMBool = LLVMBool CUInt deriving Show

 foreign import ccall unsafe "LLVMIsMultithreaded"
   isMultithreaded :: IO LLVMBool

 main :: IO ()
 main = isMultithreaded >>= print
 }}}

 If you compile it, it works OK:

 {{{
 $ ghc LLVM.hs -fforce-recomp $(llvm-config --libs) $(llvm-config --system-
 libs) -lstdc++-6 -lgcc_s_seh-1
 [1 of 1] Compiling Main             ( LLVM.hs, LLVM.o )
 Linking LLVM.exe ...
 $ ./LLVM
 LLVMBool 1
 }}}

 Or, if you're allergic to `llvm-config`:

 {{{
 $ ghc LLVM.hs -fforce-recomp -lLLVMLTO -lLLVMObjCARCOpts -lLLVMSymbolize
 -lLLVMDebugInfoPDB -lLLVMDebugInfoDWARF -lLLVMGlobalISel -lLLVMCoverage
 -lLLVMTableGen -lLLVMLineEditor -lLLVMOrcJIT -lLLVMMIRParser
 -lLLVMARMDisassembler -lLLVMARMCodeGen -lLLVMARMAsmParser -lLLVMARMDesc
 -lLLVMARMInfo -lLLVMARMAsmPrinter -lLLVMObjectYAML -lLLVMLibDriver
 -lLLVMOption -lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen
 -lLLVMSelectionDAG -lLLVMAsmPrinter -lLLVMDebugInfoCodeView -lLLVMX86Desc
 -lLLVMMCDisassembler -lLLVMX86Info -lLLVMX86AsmPrinter -lLLVMX86Utils
 -lLLVMMCJIT -lLLVMPasses -lLLVMipo -lLLVMVectorize -lLLVMLinker
 -lLLVMIRReader -lLLVMAsmParser -lLLVMInterpreter -lLLVMExecutionEngine
 -lLLVMRuntimeDyld -lLLVMObject -lLLVMMCParser -lLLVMCodeGen -lLLVMTarget
 -lLLVMScalarOpts -lLLVMInstCombine -lLLVMInstrumentation
 -lLLVMTransformUtils -lLLVMMC -lLLVMBitWriter -lLLVMBitReader
 -lLLVMAnalysis -lLLVMProfileData -lLLVMCore -lLLVMSupport -lpsapi
 -lshell32 -lole32 -luuid -lstdc++-6 -lgcc_s_seh-1
 [1 of 1] Compiling Main             ( LLVM.hs, LLVM.o )
 Linking LLVM.exe ...
 $ ./LLVM
 LLVMBool 1
 }}}

 If you load it into GHCi, however, things go awry:

 {{{
 $ ghci $(llvm-config --libs) $(llvm-config --system-libs) -lgcc_s_seh-1
 GHCi, version 8.0.2: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from
 C:\Users\RyanGlScott\AppData\Roaming\ghc\ghci.conf
 Ok, modules loaded: Main (LLVM.o).
 > main
 ghc.exe: LLVM.o: unknown symbol `LLVMIsMultithreaded'
 }}}

 On GHC 8.0.1 and HEAD, it's a slightly different error:

 {{{
 > main

 ByteCodeLink: can't find label
 During interactive linking, GHCi couldn't find the following symbol:
   LLVMIsMultithreaded
 This may be due to you not asking GHCi to load extra object files,
 archives or DLLs needed by your current session.  Restart GHCi, specifying
 the missing library using the -L/path/to/object/dir and -lmissinglibname
 flags, or simply by naming the relevant files on the GHCi command line.
 Alternatively, this link failure might indicate a bug in GHCi.
 If you suspect the latter, please send a bug report to:
   glasgow-haskell-bugs at haskell.org
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13093>
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