Allow getting the address of the value in a PointerUnion or PointerIntPair if one is

confident enough that he knows what he is doing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126019 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/PointerIntPair.h

@@ -91,6 +91,13 @@ public:
     Value |= IntVal << IntShift;  // Set new integer.
   }
 
+  PointerTy const *getAddrOfPointer() const {
+    assert(Value == reinterpret_cast<intptr_t>(getPointer()) &&
+           "Can only return the address if IntBits is cleared and "
+           "PtrTraits doesn't change the pointer");
+    return reinterpret_cast<PointerTy const *>(&Value);
+  }
+
   void *getOpaqueValue() const { return reinterpret_cast<void*>(Value); }
   void setFromOpaqueValue(void *Val) { Value = reinterpret_cast<intptr_t>(Val);}
 

include/llvm/ADT/PointerUnion.h

@@ -107,6 +107,18 @@ namespace llvm {
       if (is<T>()) return get<T>();
       return T();
     }
+
+    /// \brief If the union is set to the first pointer type we can get an
+    /// address pointing to it.
+    template <typename T>
+    PT1 const *getAddrOf() const {
+      assert(is<PT1>() && "Val is not the first pointer");
+      assert(get<PT1>() == Val.getPointer() &&
+         "Can't get the address because PointerLikeTypeTraits changes the ptr");
+      T const *can_only_get_address_of_first_pointer_type
+                        = reinterpret_cast<PT1 const *>(Val.getAddrOfPointer());
+      return can_only_get_address_of_first_pointer_type;
+    }
     
     /// Assignment operators - Allow assigning into this union from either
     /// pointer type, setting the discriminator to remember what it came from.