[clang][Interp][NFC] Move collectBaseOffset() to Context

We will need this outside of ByteCodeExprGen later.

Author: tbaederr

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -110,8 +110,8 @@ bool ByteCodeExprGen<Emitter>::VisitCastExpr(const CastExpr *CE) {
     if (!this->visit(SubExpr))
       return false;
 
-    unsigned DerivedOffset = collectBaseOffset(getRecordTy(CE->getType()),
-                                               getRecordTy(SubExpr->getType()));
+    unsigned DerivedOffset =
+        collectBaseOffset(CE->getType(), SubExpr->getType());
 
     return this->emitGetPtrBasePop(DerivedOffset, CE);
   }
@@ -120,8 +120,8 @@ bool ByteCodeExprGen<Emitter>::VisitCastExpr(const CastExpr *CE) {
     if (!this->visit(SubExpr))
       return false;
 
-    unsigned DerivedOffset = collectBaseOffset(getRecordTy(SubExpr->getType()),
-                                               getRecordTy(CE->getType()));
+    unsigned DerivedOffset =
+        collectBaseOffset(SubExpr->getType(), CE->getType());
 
     return this->emitGetPtrDerivedPop(DerivedOffset, CE);
   }
@@ -3529,35 +3529,17 @@ void ByteCodeExprGen<Emitter>::emitCleanup() {
 
 template <class Emitter>
 unsigned
-ByteCodeExprGen<Emitter>::collectBaseOffset(const RecordType *BaseType,
-                                            const RecordType *DerivedType) {
-  assert(BaseType);
-  assert(DerivedType);
-  const auto *FinalDecl = cast<CXXRecordDecl>(BaseType->getDecl());
-  const RecordDecl *CurDecl = DerivedType->getDecl();
-  const Record *CurRecord = getRecord(CurDecl);
-  assert(CurDecl && FinalDecl);
-
-  unsigned OffsetSum = 0;
-  for (;;) {
-    assert(CurRecord->getNumBases() > 0);
-    // One level up
-    for (const Record::Base &B : CurRecord->bases()) {
-      const auto *BaseDecl = cast<CXXRecordDecl>(B.Decl);
-
-      if (BaseDecl == FinalDecl || BaseDecl->isDerivedFrom(FinalDecl)) {
-        OffsetSum += B.Offset;
-        CurRecord = B.R;
-        CurDecl = BaseDecl;
-        break;
-      }
-    }
-    if (CurDecl == FinalDecl)
-      break;
-  }
+ByteCodeExprGen<Emitter>::collectBaseOffset(const QualType BaseType,
+                                            const QualType DerivedType) {
+  const auto extractRecordDecl = [](QualType Ty) -> const CXXRecordDecl * {
+    if (const auto *PT = dyn_cast<PointerType>(Ty))
+      return PT->getPointeeType()->getAsCXXRecordDecl();
+    return Ty->getAsCXXRecordDecl();
+  };
+  const CXXRecordDecl *BaseDecl = extractRecordDecl(BaseType);
+  const CXXRecordDecl *DerivedDecl = extractRecordDecl(DerivedType);
 
-  assert(OffsetSum > 0);
-  return OffsetSum;
+  return Ctx.collectBaseOffset(BaseDecl, DerivedDecl);
 }
 
 /// Emit casts from a PrimType to another PrimType.

clang/lib/AST/Interp/ByteCodeExprGen.h

@@ -283,8 +283,8 @@ class ByteCodeExprGen : public ConstStmtVisitor<ByteCodeExprGen<Emitter>, bool>,
 
   bool emitRecordDestruction(const Record *R);
   bool emitDestruction(const Descriptor *Desc);
-  unsigned collectBaseOffset(const RecordType *BaseType,
-                             const RecordType *DerivedType);
+  unsigned collectBaseOffset(const QualType BaseType,
+                             const QualType DerivedType);
 
 protected:
   /// Variable to storage mapping.

clang/lib/AST/Interp/Context.cpp

@@ -262,3 +262,36 @@ const Function *Context::getOrCreateFunction(const FunctionDecl *FD) {
 
   return Func;
 }
+
+unsigned Context::collectBaseOffset(const RecordDecl *BaseDecl,
+                                    const RecordDecl *DerivedDecl) const {
+  assert(BaseDecl);
+  assert(DerivedDecl);
+  const auto *FinalDecl = cast<CXXRecordDecl>(BaseDecl);
+  const RecordDecl *CurDecl = DerivedDecl;
+  const Record *CurRecord = P->getOrCreateRecord(CurDecl);
+  assert(CurDecl && FinalDecl);
+
+  unsigned OffsetSum = 0;
+  for (;;) {
+    assert(CurRecord->getNumBases() > 0);
+    // One level up
+    for (const Record::Base &B : CurRecord->bases()) {
+      const auto *BaseDecl = cast<CXXRecordDecl>(B.Decl);
+
+      if (BaseDecl == FinalDecl || BaseDecl->isDerivedFrom(FinalDecl)) {
+        OffsetSum += B.Offset;
+        CurRecord = B.R;
+        CurDecl = BaseDecl;
+        break;
+      }
+    }
+    if (CurDecl == FinalDecl)
+      break;
+
+    // break;
+  }
+
+  assert(OffsetSum > 0);
+  return OffsetSum;
+}

clang/lib/AST/Interp/Context.h

@@ -104,6 +104,9 @@ class Context final {
   /// Returns the program. This is only needed for unittests.
   Program &getProgram() const { return *P.get(); }
 
+  unsigned collectBaseOffset(const RecordDecl *BaseDecl,
+                             const RecordDecl *DerivedDecl) const;
+
 private:
   /// Runs a function.
   bool Run(State &Parent, const Function *Func, APValue &Result);