[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, 5 insertions, 12 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 6e777fb..908ac31 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -7891,16 +7891,10 @@ bool DecomposePrintfHandler::HandlePrintfSpecifier(
 template<typename MemberKind>
 static llvm::SmallPtrSet<MemberKind*, 1>
 CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
-  const RecordType *RT = Ty->getAs<RecordType>();
+  auto *RD = Ty->getAsCXXRecordDecl();
   llvm::SmallPtrSet<MemberKind*, 1> Results;
 
-  if (!RT)
-    return Results;
-  CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getOriginalDecl());
-  if (!RD)
-    return Results;
-  RD = RD->getDefinition();
-  if (!RD)
+  if (!RD || !(RD->isBeingDefined() || RD->isCompleteDefinition()))
     return Results;
 
   LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(),
@@ -10063,17 +10057,16 @@ void Sema::CheckMemaccessArguments(const CallExpr *Call,
         PDiag(diag::warn_arc_object_memaccess)
           << ArgIdx << FnName << PointeeTy
           << Call->getCallee()->getSourceRange());
-    else if (const auto *RT = PointeeTy->getAs<RecordType>()) {
+    else if (const auto *RD = PointeeTy->getAsRecordDecl()) {
 
       // FIXME: Do not consider incomplete types even though they may be
       // completed later. GCC does not diagnose such code, but we may want to
       // consider diagnosing it in the future, perhaps under a different, but
       // related, diagnostic group.
       bool NonTriviallyCopyableCXXRecord =
-          getLangOpts().CPlusPlus && !RT->isIncompleteType() &&
-          !RT->desugar().isTriviallyCopyableType(Context);
+          getLangOpts().CPlusPlus && RD->isCompleteDefinition() &&
+          !PointeeTy.isTriviallyCopyableType(Context);
 
-      const auto *RD = RT->getOriginalDecl()->getDefinitionOrSelf();
       if ((BId == Builtin::BImemset || BId == Builtin::BIbzero) &&
           RD->isNonTrivialToPrimitiveDefaultInitialize()) {
         DiagRuntimeBehavior(Dest->getExprLoc(), Dest,