[clang] [Clang][objectsize] Generate object size calculation for sub-objects (PR #86858)

[Eli Friedman via cfe-commits]

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@@ -1052,6 +1053,165 @@ CodeGenFunction::emitFlexibleArrayMemberSize(const Expr *E, unsigned Type,
   return Builder.CreateSelect(Cmp, Res, ConstantInt::get(ResType, 0, IsSigned));
 }
 
+namespace {
+
+class ObjectSizeVisitor
+    : public ConstStmtVisitor<ObjectSizeVisitor, const Expr *> {
+  bool SkipASE;
+
+public:
+  ObjectSizeVisitor(bool SkipASE = false) : SkipASE(SkipASE) {}
+
+  const Expr *Visit(const Expr *E) {
+    return ConstStmtVisitor<ObjectSizeVisitor, const Expr *>::Visit(E);
+  }
+
+  const Expr *VisitStmt(const Stmt *S) { return nullptr; }
+
+  const Expr *VisitDeclRefExpr(const DeclRefExpr *E) { return E; }
+  const Expr *VisitMemberExpr(const MemberExpr *E) { return E; }
+  const Expr *VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
+    return SkipASE ? Visit(E->getBase()) : E;
+  }
+
+  const Expr *VisitCastExpr(const CastExpr *E) {
+    return Visit(E->getSubExpr());
+  }
+  const Expr *VisitParenExpr(const ParenExpr *E) {
+    return Visit(E->getSubExpr());
+  }
+  const Expr *VisitUnaryAddrOf(const clang::UnaryOperator *E) {
+    return Visit(E->getSubExpr());
+  }
+  const Expr *VisitUnaryDeref(const clang::UnaryOperator *E) {
+    return Visit(E->getSubExpr());
+  }
+};
+
+} // end anonymous namespace
+
+/// getLastDecl - Return the last FieldDecl in the struct.
+static const FieldDecl *getLastDecl(const RecordDecl *RD) {
+  const Decl *LastDecl = nullptr;
+  for (const Decl *D : RD->decls())
+    if (isa<FieldDecl>(D) || isa<RecordDecl>(D))
----------------
efriedma-quic wrote:

Why are you visiting RecordDecls?

https://github.com/llvm/llvm-project/pull/86858