[Coroutines] Support opaque pointers in solveTypeName()

[nikic]

Summary

As far as I can tell, these names are only intended to be informative, so just use a generic "PointerType" for opaque pointers.

The code in solveDIType also treats pointers as basic types (and does not try to encode the pointed-to type further), so I believe this should be fine.

[ChuanqiXu]

LGTM.

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

static StringRef solveTypeName(Type *Ty) {
   if (Ty->isFloatingPointTy()) {
     if (Ty->isFloatTy())
       return "__float_";
     if (Ty->isDoubleTy())
       return "__double_";
     return "__floating_type_";
   }
 
-  if (Ty->isPointerTy()) {
-    auto *PtrTy = cast<PointerType>(Ty);
-    Type *PointeeTy = PtrTy->getPointerElementType();
+  if (auto *PtrTy = dyn_cast<PointerType>(Ty)) {
+    if (PtrTy->isOpaque())
+      return "PointerType";
+    Type *PointeeTy = PtrTy->getNonOpaquePointerElementType();
     auto Name = solveTypeName(PointeeTy);
     if (Name == "UnknownType")
       return "PointerType";
     SmallString<16> Buffer;
     Twine(Name + "_Ptr").toStringRef(Buffer);
     auto *MDName = MDString::get(Ty->getContext(), Buffer.str());
     return MDName->getString();
   }