lebedev.ri added a comment. In D137381#3907104 <https://reviews.llvm.org/D137381#3907104>, @MaskRay wrote:
> In your example, `clang++ a.cc; ./a.out` gives a libstdc++ error: > > terminate called after throwing an instance of 'int' > > libc++'s is similar. That's great, but just a symptom of misreduced testcase. The whole problem is that in the original bug *no* abort happened at runtime, the program terminated successfully, with a mysterious leak. > footgun is nounwind (due to the GNU pure attribute), so Clang uses `call` > instead of `invoke` and the function call is described by a call site entry > with a zero action_record_offset (i.e. not a handler) in `.gcc_except_table`. > In `_Unwind_RaiseException` called by `__cxa_throw`, the missing exception > handler causes `__terminate`. > > `g++ a.cc; ./a.out` succeeds, because its `footgun` call is caught by `catch > (...)`. (Perhaps GCC doesn't have Clang's nounwind optimization.) > > The patch doesn't implement the runtime correctly (I get a linker error) so I > cannot try it out. How expensive is your instrumentation? > Does it work with `-fno-exceptions` intermediate functions? (Unwinding > through such functions should fail as well). Note that this check can be done > today,without any instrumentation: just use `-fno-asynchronous-unwind-tables` > (for some targets which default to async unwind tables (aarch64,x86,etc)). > If the process installs a SIGABRT signal handler, the stack trace can be > printed when `__terminate` calls `abort`. I find this comment non-welcoming and discouraging. I just wanted to get something posted when i had something to post already. All of this needs a bit more time. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D137381/new/ https://reviews.llvm.org/D137381 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
