rjmccall added a comment. In D80344#2293954 <https://reviews.llvm.org/D80344#2293954>, @tentzen wrote:
> In D80344#2291926 <https://reviews.llvm.org/D80344#2291926>, @rjmccall wrote: > >> Okay. I think we're on the same page about representation now. If you can >> come up with a good replacement for "eha" in the intrinsic names, I think >> this is pretty much ready to go. > > how about seh.cppscope.begin() and seh.cppscope.end()? or any suggestion? I like that better. Maybe even just `seh.scope.begin`? Or `seh.cleanupscope.begin`? Cleanups aren't *inherently* a C++ feature, it's just that C doesn't officially have them and MSVC doesn't really support any non-C++ languages that do. > As for pairing question, we simply utilizes existent Cleanup mechanism as you > described in which abnormal exits and normal fall-through are merged in a > 'cleanup' pad. What this implementation does is to inject a scope.begin > right after a ctor and a scope.end right before dtor in cleanup-pad. Use the > same example, it will be something like below: > > void test(int x, int &state) { > int jumpdest; > state = 0; > std::string a; > **seh.cppscope.begin(); // for object a** > state = 1; > if (x > 0) { > state = 2; > std::string b; > **seh.cppscope.begin(); // for b** > state = 3; > if (x > 10) { > state = 4; > jumpdest = 0; > goto destroy_b; > } > state = 5; > std::string c; > **seh.cppscope.begin(); // for c** > state = 6; > **seh.cppscope.end(); // for c dtor** > c.~std::string(); > jumpdest = 1; > destroy_b: > **seh.cppscope.end(); // for b dtor** > b.~std::string(); > switch (jumpdest) { > case 0: goto destroy_a; > case 1: goto fallthrough; > } > fallthrough: > ; > } > state = 7; > destroy_a: > **seh.cppscope.begin(); // for a dtor ** > a.~std::string(); > } Okay. I feel fairly convinced that this will work for most cleanup situations. You might need to do some IR-testing work in Clang to make sure Clang calls seh.scope.begin the right way when emitting conditional cleanups: - We need to call it at some dominating point rather than at the current IP when we push the cleanup. - We need to call it in the right order for the cleanups we enter. Conditional cleanups come up when we need a cleanup in code that's not unconditionally run during a expression evaluation, like in the 2nd or 3rd operand of `?:` or in the RHS of `&&`. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D80344/new/ https://reviews.llvm.org/D80344 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
