assigned to @int3

This is not a subtle bug after all. Exceptions just don't work at all:

% cat throw.cc
int main() {
try {
throw 0;
} catch (int i) {
return i;
}
}
% out/gn/bin/clang++ throw.cc -fuse-ld=lld.darwinnew
lld: warning: Option `-no_deduplicate' is not yet implemented. Stay tuned...
% ./a.out ; echo $?
libc++abi.dylib: terminating with uncaught exception of type int
zsh: abort ./a.out
134

Works fine with ld64.

ObjC exceptions also don't work:

% cat throw.m
int main() {
@​try {
@​throw (void*)0;
} @​catch (id i) {
return i;
}
}
% out/gn/bin/clang++ throw.m -framework Foundation -fuse-ld=lld.darwinnew
throw.m:5:12: warning: incompatible pointer to integer conversion returning 'id' from a function with result type 'int' [-Wint-conversion]
return i;
^
1 warning generated.
lld: warning: Option `-no_deduplicate' is not yet implemented. Stay tuned...
% ./a.out
2021-01-10 13:09:10.871 a.out[73775:15821192] *** Terminating app due to uncaught exception of class 'nil'
libc++abi.dylib: terminating with uncaught exception of type nil
zsh: abort ./a.out

(Also fine with ld64.)

Yeah, the __eh_frame support is not done yet (I was just asking gkm about it yesterday).

I see some LSDA / personality stuff landed. Is this expected to work now, or not yet?

The simple examples work, but the CallWithEHFrameTest still fails. To be precise, when linking, we hit the "too many personalities for compact unwind to encode" error. Just to see what would happen, I turned that error into a warning, and then ran the resulting binary -- CatchExceptionHigher passes, but CatchExceptionLower fails. So we're not quite there yet.

Figured it out :) https://reviews.llvm.org/D97245