[clang][bytecode][NFC] Use switches for pointer type distinction (llvm#160879)

In the important places. They are all fully covered switch statements so
we know where to add code when adding a new pointer type.

Author: tbaederr

clang/lib/AST/ByteCode/Pointer.cpp

@@ -110,19 +110,21 @@ Pointer &Pointer::operator=(const Pointer &P) {
   StorageKind = P.StorageKind;
   Offset = P.Offset;
 
-  if (P.isBlockPointer()) {
+  switch (StorageKind) {
+  case Storage::Int:
+    Int = P.Int;
+    break;
+  case Storage::Block:
     BS = P.BS;
 
     if (BS.Pointee)
       BS.Pointee->addPointer(this);
-  } else if (P.isIntegralPointer()) {
-    Int = P.Int;
-  } else if (P.isFunctionPointer()) {
+    break;
+  case Storage::Fn:
     Fn = P.Fn;
-  } else if (P.isTypeidPointer()) {
+    break;
+  case Storage::Typeid:
     Typeid = P.Typeid;
-  } else {
-    assert(false && "Unhandled storage kind");
   }
   return *this;
 }
@@ -147,19 +149,21 @@ Pointer &Pointer::operator=(Pointer &&P) {
   StorageKind = P.StorageKind;
   Offset = P.Offset;
 
-  if (P.isBlockPointer()) {
+  switch (StorageKind) {
+  case Storage::Int:
+    Int = P.Int;
+    break;
+  case Storage::Block:
     BS = P.BS;
 
     if (BS.Pointee)
       BS.Pointee->addPointer(this);
-  } else if (P.isIntegralPointer()) {
-    Int = P.Int;
-  } else if (P.isFunctionPointer()) {
+    break;
+  case Storage::Fn:
     Fn = P.Fn;
-  } else if (P.isTypeidPointer()) {
+    break;
+  case Storage::Typeid:
     Typeid = P.Typeid;
-  } else {
-    assert(false && "Unhandled storage kind");
   }
   return *this;
 }
@@ -358,13 +362,17 @@ void Pointer::print(llvm::raw_ostream &OS) const {
 }
 
 size_t Pointer::computeOffsetForComparison() const {
-  if (isIntegralPointer())
-    return asIntPointer().Value + Offset;
-  if (isTypeidPointer())
+  switch (StorageKind) {
+  case Storage::Int:
+    return Int.Value + Offset;
+  case Storage::Block:
+    // See below.
+    break;
+  case Storage::Fn:
+    return Fn.getIntegerRepresentation() + Offset;
+  case Storage::Typeid:
     return reinterpret_cast<uintptr_t>(asTypeidPointer().TypePtr) + Offset;
-
-  if (!isBlockPointer())
-    return Offset;
+  }
 
   size_t Result = 0;
   Pointer P = *this;

clang/lib/AST/ByteCode/Pointer.h

@@ -56,7 +56,7 @@ struct TypeidPointer {
   const Type *TypeInfoType;
 };
 
-enum class Storage { Block, Int, Fn, Typeid };
+enum class Storage { Int, Block, Fn, Typeid };
 
 /// A pointer to a memory block, live or dead.
 ///
@@ -252,14 +252,16 @@ class Pointer {
 
   /// Checks if the pointer is null.
   bool isZero() const {
-    if (isBlockPointer())
+    switch (StorageKind) {
+    case Storage::Int:
+      return Int.Value == 0 && Offset == 0;
+    case Storage::Block:
       return BS.Pointee == nullptr;
-    if (isFunctionPointer())
+    case Storage::Fn:
       return Fn.isZero();
-    if (isTypeidPointer())
+    case Storage::Typeid:
       return false;
-    assert(isIntegralPointer());
-    return Int.Value == 0 && Offset == 0;
+    }
   }
   /// Checks if the pointer is live.
   bool isLive() const {