[clang] NFC: change more places to use Type::getAsTagDecl and friends (#155313)

This changes a bunch of places which use getAs<TagType>, including
derived types, just to obtain the tag definition.

This is preparation for #155028, offloading all the changes that PR used
to introduce which don't depend on any new helpers.

1 files changed, 7 insertions, 10 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index cdb63db..ee0ac4e 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -15407,10 +15407,9 @@ bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
 
     case OffsetOfNode::Field: {
       FieldDecl *MemberDecl = ON.getField();
-      const RecordType *RT = CurrentType->getAs<RecordType>();
-      if (!RT)
+      const auto *RD = CurrentType->getAsRecordDecl();
+      if (!RD)
         return Error(OOE);
-      RecordDecl *RD = RT->getOriginalDecl()->getDefinitionOrSelf();
       if (RD->isInvalidDecl()) return false;
       const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
       unsigned i = MemberDecl->getFieldIndex();
@@ -15429,22 +15428,20 @@ bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
         return Error(OOE);
 
       // Find the layout of the class whose base we are looking into.
-      const RecordType *RT = CurrentType->getAs<RecordType>();
-      if (!RT)
+      const auto *RD = CurrentType->getAsCXXRecordDecl();
+      if (!RD)
         return Error(OOE);
-      RecordDecl *RD = RT->getOriginalDecl()->getDefinitionOrSelf();
       if (RD->isInvalidDecl()) return false;
       const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
 
       // Find the base class itself.
       CurrentType = BaseSpec->getType();
-      const RecordType *BaseRT = CurrentType->getAs<RecordType>();
-      if (!BaseRT)
+      const auto *BaseRD = CurrentType->getAsCXXRecordDecl();
+      if (!BaseRD)
         return Error(OOE);
 
       // Add the offset to the base.
-      Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(
-          BaseRT->getOriginalDecl()->getDefinitionOrSelf()));
+      Result += RL.getBaseClassOffset(BaseRD);
       break;
     }
     }