Codon v0.17.0 compilation failure with LLVM 18

[admnd]

On a Gentoo box with LLVM 18.1.8 the build aborts with:

[ 77%] Building CXX object CMakeFiles/codonc.dir/codon/parser/visitors/typecheck/assign.cpp.o
[ 77%] Building CXX object CMakeFiles/codonc.dir/codon/parser/visitors/typecheck/basic.cpp.o
[ 77%] Building CXX object CMakeFiles/codonc.dir/codon/parser/visitors/typecheck/call.cpp.o
/tmp/codon/codon/compiler/memory_manager.cpp: In member function ‘virtual void codon::BoehmGCJITLinkMemoryManager::allocate(const llvm::jitlink::JITLinkDylib*, llvm::jitlink::LinkGraph&, llvm::jitlink::JITLinkMemoryManager::OnAllocatedFunction)’:
/tmp/codon/codon/compiler/memory_manager.cpp:182:13: error: ‘class llvm::orc::AllocGroup’ has no member named ‘getMemLifetimePolicy’; did you mean ‘constexpr const unsigned int llvm::orc::AllocGroup::BitsForLifetimePolicy’? (not accessible from this context)
  182 |         (AG.getMemLifetimePolicy() == llvm::orc::MemLifetimePolicy::Standard)
      |             ^~~~~~~~~~~~~~~~~~~~
In file included from /usr/lib/llvm/18/include/llvm/ExecutionEngine/JITLink/JITLinkMemoryManager.h:21,
                 from /usr/lib/llvm/18/include/llvm/ExecutionEngine/JITLink/JITLink.h:20,
                 from /tmp/codon/./codon/cir/llvm/llvm.h:28,
                 from /tmp/codon/codon/compiler/memory_manager.h:9,
                 from /tmp/codon/codon/compiler/memory_manager.cpp:3:
/usr/lib/llvm/18/include/llvm/ExecutionEngine/Orc/Shared/MemoryFlags.h:115:29: note: declared private here
  115 |   static constexpr unsigned BitsForLifetimePolicy = 2;
      |                             ^~~~~~~~~~~~~~~~~~~~~
/tmp/codon/codon/compiler/memory_manager.cpp:182:50: error: ‘llvm::orc::MemLifetimePolicy’ has not been declared
  182 |         (AG.getMemLifetimePolicy() == llvm::orc::MemLifetimePolicy::Standard)
      |                                                  ^~~~~~~~~~~~~~~~~
/tmp/codon/codon/compiler/memory_manager.cpp:186:36: error: expected primary-expression before ‘char’
  186 |     Seg.WorkingMem = SegAddr.toPtr<char *>();
make[2]: *** [CMakeFiles/codonc.dir/build.make:156: CMakeFiles/codonc.dir/codon/compiler/memory_manager.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:812: CMakeFiles/codonc.dir/all] Error 2

[arshajii]

Hi @admnd -- Codon requires LLVM 17 currently. We use a LLVM fork with a few modifications: https://github.com/exaloop/llvm-project