[clang][Interp][NFC] Add more assertions to add/removePointer

Author: tbaederr

clang/lib/AST/Interp/InterpBlock.cpp

@@ -31,9 +31,13 @@ void Block::addPointer(Pointer *P) {
   P->Next = Pointers;
   P->Prev = nullptr;
   Pointers = P;
+#ifndef NDEBUG
+  assert(hasPointer(P));
+#endif
 }
 
 void Block::removePointer(Pointer *P) {
+  assert(P->isBlockPointer());
   assert(P);
   if (IsStatic) {
     assert(!Pointers);
@@ -51,6 +55,10 @@ void Block::removePointer(Pointer *P) {
     P->Prev->Next = P->Next;
   if (P->Next)
     P->Next->Prev = P->Prev;
+  P->PointeeStorage.BS.Pointee = nullptr;
+#ifndef NDEBUG
+  assert(!hasPointer(P));
+#endif
 }
 
 void Block::cleanup() {

clang/lib/AST/Interp/Pointer.cpp

@@ -60,6 +60,7 @@ Pointer::~Pointer() {
 
   if (Block *Pointee = PointeeStorage.BS.Pointee) {
     Pointee->removePointer(this);
+    PointeeStorage.BS.Pointee = nullptr;
     Pointee->cleanup();
   }
 }
@@ -68,8 +69,15 @@ void Pointer::operator=(const Pointer &P) {
   // If the current storage type is Block, we need to remove
   // this pointer from the block.
   if (isBlockPointer()) {
+    if (P.isBlockPointer() && this->block() == P.block()) {
+      Offset = P.Offset;
+      PointeeStorage.BS.Base = P.PointeeStorage.BS.Base;
+      return;
+    }
+
     if (Block *Pointee = PointeeStorage.BS.Pointee) {
       Pointee->removePointer(this);
+      PointeeStorage.BS.Pointee = nullptr;
       Pointee->cleanup();
     }
   }
@@ -96,8 +104,16 @@ void Pointer::operator=(Pointer &&P) {
   // If the current storage type is Block, we need to remove
   // this pointer from the block.
   if (isBlockPointer()) {
+    if (P.isBlockPointer() && this->block() == P.block()) {
+      Offset = P.Offset;
+      PointeeStorage.BS.Base = P.PointeeStorage.BS.Base;
+      return;
+    }
+
     if (Block *Pointee = PointeeStorage.BS.Pointee) {
+      assert(P.block() != this->block());
       Pointee->removePointer(this);
+      PointeeStorage.BS.Pointee = nullptr;
       Pointee->cleanup();
     }
   }