Problems throwing and catching exceptions on OS X with -fno-rtti

Question

The issue is somewhat similar to this question but the accepted answer does not really propose a solution or workaround.

In our project, we have a dylib and the main

Answer 1

Well, even though I have accepted an answer it did not solve all problems. So I'm writing down the solution which did work in the end.

I made a small tool for post-processing the object files and marking the local symbols as UNDEF. This forces the linker to use definitions from libstdc++ and not local ones from the file. The basic approach of the tool is:

1. load the Mach-O header
2. walk the load commands and find the LC_SYMTAB command
3. load the list of symbols (struct nlist) and the strings
4. walk the symbols and look for those that we need (e.g. __ZTISt9bad_alloc)
5. set the found symbols' type to N_UNDF|N_EXT.
6. after processing, write the modified symbol table back to the file.

(I also made a similar implementation for ELF)

I post-process any file that's using std exceptions, either for throwing or for catching. To make sure the file list does not go stale, I added a post-link check for unwanted local symbols using nm.

This seems to resolve all the problems I've had so far.