Clarify which type "Label" refers to (generic vs X86)

src/IceAssemblerX86Base.h

Index: src/IceAssemblerX86Base.h
diff --git a/src/IceAssemblerX86Base.h b/src/IceAssemblerX86Base.h
index 252903ee25078bcb1eea2670d1b3c6429634041c..9edf501dbcb6111f1b958e6e1717b4bc7b4d31ed 100644
--- a/src/IceAssemblerX86Base.h
+++ b/src/IceAssemblerX86Base.h
@@ -72,7 +72,7 @@ private:
 };
 
 /// X86 allows near and far jumps.
-class Label final : public Ice::Label {
+class Label final : public LabelBase {
   Label(const Label &) = delete;
   Label &operator=(const Label &) = delete;
 
@@ -81,7 +81,7 @@ public:
   ~Label() = default;
 
   void finalCheck() const override {
-    Ice::Label::finalCheck();
+    Ice::LabelBase::finalCheck();
     assert(!hasNear());
   }
 
@@ -96,7 +96,7 @@ public:
 
   bool hasNear() const { return !UnresolvedNearPositions.empty(); }
   bool isUnused() const override {
-    return Ice::Label::isUnused() && !hasNear();
+    return Ice::LabelBase::isUnused() && !hasNear();
   }
 
 private:
@@ -150,8 +150,9 @@ public:
       nop(Padding);
   }
 
-  Label *getOrCreateCfgNodeLabel(SizeT NodeNumber) override;
+  LabelBase *getCfgNodeLabel(SizeT NodeNumber) override;
   void bindCfgNodeLabel(SizeT NodeNumber) override;
+  Label *getOrCreateCfgNodeLabel(SizeT Number);
   Label *getOrCreateLocalLabel(SizeT Number);
   void bindLocalLabel(SizeT Number);