ORC/JLJIT: Segfault on master

[maleadt]

MWE:

using LLVM

function main()
    @dispose jljit=JuliaOJIT() begin
        jd = JITDylib(jljit)

        fn = "SomeFunction"
        obj = @dispose ctx=Context() mod=LLVM.Module("jit") begin
            ft = LLVM.FunctionType(LLVM.VoidType())
            fun = LLVM.Function(mod, fn, ft)

            @dispose builder=IRBuilder() begin
                entry = BasicBlock(fun, "entry")
                position!(builder, entry)
                ret!(builder)
            end
            verify(mod)

            @dispose tm=JITTargetMachine() begin
                emit(tm, mod, LLVM.API.LLVMObjectFile)
            end
        end
        add!(jljit, jd, MemoryBuffer(obj))
        lookup(jljit, fn)
        empty!(jd)
    end
end

isinteractive() || main()

[460761] signal 11 (1): Segmentation fault
in expression starting at /home/tim/Julia/pkg/LLVM/wip.jl:30
deregisterEHFrames at /cache/build/builder-demeter6-4/julialang/julia-master/src/jitlayers.cpp:1274
_ZN4llvm3orc24RTDyldObjectLinkingLayer21handleRemoveResourcesERNS0_8JITDylibEm at /home/tim/Julia/depot/juliaup/julia-nightly/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm3orc16ExecutionSession21removeResourceTrackerERNS0_15ResourceTrackerE at /home/tim/Julia/depot/juliaup/julia-nightly/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
_ZN4llvm3orc8JITDylib5clearEv at /home/tim/Julia/depot/juliaup/julia-nightly/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
LLVMOrcJITDylibClear at /home/tim/Julia/depot/juliaup/julia-nightly/bin/../lib/julia/libLLVM.so.18.1jl (unknown line)
LLVMOrcJITDylibClear at /home/tim/Julia/pkg/LLVM/lib/18/libLLVM.jl:10213 [inlined]
empty! at /home/tim/Julia/pkg/LLVM/src/orc.jl:211 [inlined]
macro expansion at /home/tim/Julia/pkg/LLVM/wip.jl:26 [inlined]
macro expansion at /home/tim/Julia/pkg/LLVM/src/base.jl:97 [inlined]
main at /home/tim/Julia/pkg/LLVM/wip.jl:5
unknown function (ip: 0x7af4ad300abe) at (unknown file)
jl_apply at /cache/build/builder-demeter6-4/julialang/julia-master/src/julia.h:2233 [inlined]
do_call at /cache/build/builder-demeter6-4/julialang/julia-master/src/interpreter.c:125
eval_value at /cache/build/builder-demeter6-4/julialang/julia-master/src/interpreter.c:243
eval_stmt_value at /cache/build/builder-demeter6-4/julialang/julia-master/src/interpreter.c:194 [inlined]
eval_body at /cache/build/builder-demeter6-4/julialang/julia-master/src/interpreter.c:691
jl_interpret_toplevel_thunk at /cache/build/builder-demeter6-4/julialang/julia-master/src/interpreter.c:896
jl_toplevel_eval_flex at /cache/build/builder-demeter6-4/julialang/julia-master/src/toplevel.c:1070
jl_toplevel_eval_flex at /cache/build/builder-demeter6-4/julialang/julia-master/src/toplevel.c:1010
ijl_toplevel_eval at /cache/build/builder-demeter6-4/julialang/julia-master/src/toplevel.c:1082
ijl_toplevel_eval_in at /cache/build/builder-demeter6-4/julialang/julia-master/src/toplevel.c:1127
eval at ./boot.jl:479
include_string at ./loading.jl:2846
_include at ./loading.jl:2906
include at ./Base.jl:300
exec_options at ./client.jl:329
_start at ./client.jl:558
jfptr__start_108480.1 at /home/tim/Julia/depot/juliaup/julia-nightly/lib/julia/sys.so (unknown line)
jl_apply at /cache/build/builder-demeter6-4/julialang/julia-master/src/julia.h:2233 [inlined]
true_main at /cache/build/builder-demeter6-4/julialang/julia-master/src/jlapi.c:922
jl_repl_entrypoint at /cache/build/builder-demeter6-4/julialang/julia-master/src/jlapi.c:1081
main at /cache/build/builder-demeter6-4/julialang/julia-master/cli/loader_exe.c:58
unknown function (ip: 0x7af4c8110e07) at /usr/lib/libc.so.6
__libc_start_main at /usr/lib/libc.so.6 (unknown line)
unknown function (ip: 0x4010b8) at /workspace/srcdir/glibc-2.17/csu/../sysdeps/x86_64/start.S
Allocations: 3272445 (Pool: 3272359; Big: 86); GC: 4

[maleadt]

Bisected to JuliaLang/julia#56179 (presumably something in JuliaLang/julia@f0ab810).

@vtjnash Any quick thoughts as to why LLVMOrcJITDylibClear would crash now?

[vtjnash]

The ForwardingMemoryManager destroys its internal reference after the call to finalizeMemory

[maleadt]

Implying that's a bug with ForwardingMemoryManager, or what are you saying? AFAICT it should be allowed to call JITDylib::clear here.

[vtjnash]

We've never supported clear before, but usually stubbed it to a no-op, which I guess could be restored as the behavior here (e.g. delete the code that is crashing)