[clang][Interp][NFC] Rename locals and add assertions to virtual casts

Author: tbaederr

clang/lib/AST/Interp/Interp.h

@@ -1355,12 +1355,14 @@ inline bool VirtBaseHelper(InterpState &S, CodePtr OpPC, const RecordDecl *Decl,
   while (Base.isBaseClass())
     Base = Base.getBase();
 
-  auto *Field = Base.getRecord()->getVirtualBase(Decl);
-  S.Stk.push<Pointer>(Base.atField(Field->Offset));
+  const Record::Base *VirtBase = Base.getRecord()->getVirtualBase(Decl);
+  S.Stk.push<Pointer>(Base.atField(VirtBase->Offset));
   return true;
 }
 
-inline bool GetPtrVirtBase(InterpState &S, CodePtr OpPC, const RecordDecl *D) {
+inline bool GetPtrVirtBasePop(InterpState &S, CodePtr OpPC,
+                              const RecordDecl *D) {
+  assert(D);
   const Pointer &Ptr = S.Stk.pop<Pointer>();
   if (!CheckNull(S, OpPC, Ptr, CSK_Base))
     return false;
@@ -1369,6 +1371,7 @@ inline bool GetPtrVirtBase(InterpState &S, CodePtr OpPC, const RecordDecl *D) {
 
 inline bool GetPtrThisVirtBase(InterpState &S, CodePtr OpPC,
                                const RecordDecl *D) {
+  assert(D);
   if (S.checkingPotentialConstantExpression())
     return false;
   const Pointer &This = S.Current->getThis();

clang/lib/AST/Interp/Opcodes.td

@@ -336,7 +336,7 @@ def GetPtrDerivedPop : Opcode {
 }
 
 // [Pointer] -> [Pointer]
-def GetPtrVirtBase : Opcode {
+def GetPtrVirtBasePop : Opcode {
   // RecordDecl of base class.
   let Args = [ArgRecordDecl];
 }