Re: Crash occurs when catching std::exception in Objective-C++ code compiled with clang on Linux and using libobjc2

[Lobron, David]

> -fgnu-runtime is long-deprecated, and I’m not sure what happens if it’s 
> specified *after* -fobjc-runtime=.  It may override it (and default to an 
> earlier runtime target).  It’s probably best to remove it.
> 
> Did you run the libobjc2 tests (which include a test for C++ exceptions in 
> Objective-C++), and did they pass?

I had been building libobjc2 with tests disabled.  I removed the disable flag, 
and tried to compile again.  I'm finding that the compilation now fails, and 
the errors seem a bit telling, because they concern exception personalities.  
The errors are very similar:

make[4]: Entering directory 
`/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/build'
CMakeFiles/CXXExceptions.dir/CXXException.cc.o[ 55%] Building C object 
Test/CMakeFiles/BlockImpTest.dir/BlockImpTest.m.o
: In function `throw_int':
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x13):
 undefined reference to `__cxa_allocate_exception'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x1b):
 undefined reference to `typeinfo for int'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x3b):
 undefined reference to `__cxa_throw'
CMakeFiles/CXXExceptions.dir/CXXException.cc.o: In function `catchall':
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x65):
 undefined reference to `__cxa_begin_catch'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x78):
 undefined reference to `__cxa_rethrow'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x8b):
 undefined reference to `__cxa_end_catch'
CMakeFiles/CXXExceptions.dir/CXXException.cc.o: In function 
`__clang_call_terminate':
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text.__clang_call_terminate[__clang_call_terminate]+0x9):
 undefined reference to `__cxa_begin_catch'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text.__clang_call_terminate[__clang_call_terminate]+0x12):
 undefined reference to `std::terminate()'
CMakeFiles/CXXExceptions.dir/CXXException.cc.o:(.eh_frame+0x47): undefined 
reference to `__gxx_personality_v0'
Scanning dependencies of target CXXExceptions_optimised
clang-6.0: error: linker command failed with exit code 1 (use -v to see 
invocation)

And also:

CMakeFiles/CXXExceptions_optimised.dir/CXXException.cc.o: In function 
`throw_int':
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x7):
 undefined reference to `__cxa_allocate_exception'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x12):
 undefined reference to `typeinfo for int'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x1c):
 undefined reference to `__cxa_throw'
CMakeFiles/CXXExceptions_optimised.dir/CXXException.cc.o: In function 
`catchall':
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x2c):
 undefined reference to `__cxa_begin_catch'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x3b):
 undefined reference to `__cxa_rethrow'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text+0x43):
 undefined reference to `__cxa_end_catch'
CMakeFiles/CXXExceptions_optimised.dir/CXXException.cc.o: In function 
`__clang_call_terminate':
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text.__clang_call_terminate[__clang_call_terminate]+0x2):
 undefined reference to `__cxa_begin_catch'
/home/dlobron/build/clangport/akamai/libobjc2/libobjc2-1.8.1/Test/CXXException.cc:(.text.__clang_call_terminate[__clang_call_terminate]+0x7):
 undefined reference to `std::terminate()'
CMakeFiles/CXXExceptions_optimised.dir/CXXException.cc.o:(.eh_frame+0x3f): 
undefined reference to `__gxx_personality_v0'
clang-6.0: error: linker command failed with exit code 1 (use -v to see 
invocation)

I enabled messages=yes in my build, but I don't see the compilation commands - 
I'm trying now to get those.  Do these errors indicate where the problem might 
lie?

Thank you again for your help here.

--David