root@talos:/usr/src # gdb -core /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/rustc.core /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/bin/rustc
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Reading symbols from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/bin/rustc...
[New LWP 105998]
[New LWP 102835]
[New LWP 105549]
[New LWP 105995]
Core was generated by `/usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freeb'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000803272070 in llvm::Error llvm::handleErrors<llvm::toString(llvm::Error)::{lambda(llvm::ErrorInfoBase const&)#1}>(llvm::Error, llvm::toString(llvm::Error)::{lambda(llvm::ErrorInfoBase const&)#1}&&) () from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
[Current thread is 1 (LWP 105998)]
(gdb) bt 
#0  0x0000000803272070 in llvm::Error llvm::handleErrors<llvm::toString(llvm::Error)::{lambda(llvm::ErrorInfoBase const&)#1}>(llvm::Error, llvm::toString(llvm::Error)::{lambda(llvm::ErrorInfoBase const&)#1}&&) () from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#1  0x000000080326f770 in llvm::toString(llvm::Error) ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#2  0x000000080326ef3c in LLVMRustCreateThinLTOData () from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#3  0x00000008030d37dc in rustc_codegen_llvm::back::lto::thin_lto ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#4  0x00000008030d2844 in rustc_codegen_llvm::back::lto::run_thin ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#5  0x0000000803112af4 in rustc_codegen_ssa::back::write::generate_lto_work ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#6  0x00000008030b7128 in std::sys_common::backtrace::__rust_begin_short_backtrace ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#7  0x0000000803182f6c in std::panicking::try::do_call ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#8  0x0000000807e121f0 in __rust_try () from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/libstd-f472eea3f74718a6.so
#9  0x0000000807e12064 in __rust_maybe_catch_panic () from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/libstd-f472eea3f74718a6.so
#10 0x00000008030dd1cc in core::ops::function::FnOnce::call_once{{vtable-shim}} ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/librustc_driver-f915bb59bef6c2bd.so
#11 0x0000000807e0c00c in <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/libstd-f472eea3f74718a6.so
#12 0x0000000807dffda0 in std::sys_common::thread::start_thread ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/libstd-f472eea3f74718a6.so
#13 0x0000000807dd9180 in std::sys::unix::thread::Thread::new::thread_start ()
   from /usr/obj/usr/ports/lang/rust/work/rustc-1.42.0-src/build/powerpc64-unknown-freebsd/stage1/lib/libstd-f472eea3f74718a6.so
#14 0x000000080833b320 in thread_start (curthread=0x8197fb200) at /usr/src/lib/libthr/thread/thr_create.c:292
#15 0x0000000000000000 in ?? ()