[PATCH] D71491: [ubsan] Check implicit casts in ObjC for-in statements

Wed Jan 15 16:42:05 PST 2020

vsk added inline comments.

================
Comment at: compiler-rt/lib/ubsan/ubsan_value.cpp:29
+const char *__ubsan::getObjCClassName(ValueHandle Pointer) {
+#if defined(__APPLE__)
+  // We need to query the ObjC runtime for some information, but do not want
----------------
delcypher wrote:
> vsk wrote:
> > delcypher wrote:
> > > vsk wrote:
> > > > delcypher wrote:
> > > > > The compiler-rt codebase tends to use `SANITIZER_MAC` macro (defined to be 1 if Apple otherwise it's 0) rather than `__APPLE__`.
> > > > I see. That seems problematic, as it makes it tricky to add macOS-specific (or iOS-specific) functionality down the road. I don't think SANITIZER_MAC should be defined unless TARGET_OS_MACOS is true.
> > > Sorry I should clarify. `SANITIZER_MAC` is poorly named but it is defined to be `1` for Apple platforms and `0`. I'm just pointing out the convention that exists today. You're absolutely right that we might want to do different things for different Apple platforms but I don't think we want to start doing a mass re-name until arm64e and arm64_32 support are completed landed in llvm's master.
> > I think 'SANITIZER_MAC' is confusing, and my preference would be to not use it. `__APPLE__` seems clearer to me, and (IIUC) the plan is to replace usage of 'SANITIZER_MAC' with it down the line anyway?
> There aren't any plans to do it right now but cleaning this up seems like a reasonable thing to do. If you take a look at `compiler-rt/lib/sanitizer_common/sanitizer_platform.h` you'll see that we actually have `SANITIZER_<platform>` for the other platforms that seems to be set as you'd expect. It's just `SANITIZER_MAC` that's badly named.
> 
> I've filed a radar for this issue (rdar://problem/58124919). So if you prefer to use `__APPLE__` could you leave a comment with something like
> 
> ```
> // TODO(dliew): Don't use unclear `SANITIZER_MAC` here. Instead wait for its replacement rdar://problem/58124919.
> ```
> 
> Note the `TODO(<name>):` style is enforced by the sanitizer specific linter so you have to put a name there.
Thanks, done!

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  https://reviews.llvm.org/D71491/new/

https://reviews.llvm.org/D71491