[Lldb-commits] [lldb] [LLDB] Add unary operators Dereference and AddressOf to DIL (PR #134428)

[Ilia Kuklin via lldb-commits]

================
@@ -232,4 +263,105 @@ Interpreter::Visit(const IdentifierNode *node) {
   return identifier;
 }
 
-} // namespace lldb_private::dil
+llvm::Expected<lldb::ValueObjectSP>
+Interpreter::Visit(const UnaryOpNode *node) {
+  FlowAnalysis rhs_flow(
+      /* address_of_is_pending */ node->kind() == UnaryOpKind::AddrOf);
+
+  Status error;
+  auto rhs_or_err = EvaluateNode(node->rhs(), &rhs_flow);
+  if (!rhs_or_err) {
+    return rhs_or_err;
+  }
+  lldb::ValueObjectSP rhs = *rhs_or_err;
+
+  CompilerType rhs_type = rhs->GetCompilerType();
+  switch (node->kind()) {
+  case UnaryOpKind::Deref: {
+    if (rhs_type.IsArrayType())
+      rhs = ArrayToPointerConversion(rhs, m_exe_ctx_scope);
+
+    lldb::ValueObjectSP dynamic_rhs = rhs->GetDynamicValue(m_default_dynamic);
+    if (dynamic_rhs)
+      rhs = dynamic_rhs;
+
+    if (rhs->GetCompilerType().IsPointerType()) {
+      if (rhs->GetCompilerType().IsPointerToVoid()) {
+        return llvm::make_error<DILDiagnosticError>(
+            m_expr, "indirection not permitted on operand of type 'void *'",
+            node->GetLocation(), 1);
+      }
+      return EvaluateDereference(rhs);
+    }
+    lldb::ValueObjectSP child_sp = rhs->Dereference(error);
+    if (error.Success())
+      rhs = child_sp;
+
+    return rhs;
+  }
+  case UnaryOpKind::AddrOf: {
+    if (node->rhs()->is_rvalue()) {
----------------
kuilpd wrote:

>From what I could gather, the first one is `ValueObject::AddressOf` that creates a `ValueObjectConstResult` and fills in its address. The second one calls `ValueObjectConstResultImpl::AddressOf` that also creates `ValueObjectConstResult` but with no address this time (which makes sense for a const value), so the third one fails.
I'm guessing that the first `ValueObjectConstResult` is pretty much an implementation of a reference, so it has to have an address behind it so it can be dereferenced normally. 

https://github.com/llvm/llvm-project/pull/134428