[Lldb-commits] [lldb] [lldb][DataFormatter] Simplify std::unordered_map::iterator formatter (PR #97754)

[Pavel Labath via lldb-commits]

================
@@ -246,3 +270,119 @@ lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEndCreator(
   return (valobj_sp ? new LibcxxStdUnorderedMapSyntheticFrontEnd(valobj_sp)
                     : nullptr);
 }
+
+lldb_private::formatters::LibCxxUnorderedMapIteratorSyntheticFrontEnd::
+    LibCxxUnorderedMapIteratorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
+    : SyntheticChildrenFrontEnd(*valobj_sp) {
+  if (valobj_sp)
+    Update();
+}
+
+lldb::ChildCacheState lldb_private::formatters::
+    LibCxxUnorderedMapIteratorSyntheticFrontEnd::Update() {
+  m_pair_sp.reset();
+
+  ValueObjectSP valobj_sp = m_backend.GetSP();
+  if (!valobj_sp)
+    return lldb::ChildCacheState::eRefetch;
+
+  TargetSP target_sp(valobj_sp->GetTargetSP());
+
+  if (!target_sp)
+    return lldb::ChildCacheState::eRefetch;
+
+  // Get the unordered_map::iterator
+  // m_backend is an 'unordered_map::iterator', aka a
+  // '__hash_map_iterator<__hash_table::iterator>'
+  //
+  // __hash_map_iterator::__i_ is a __hash_table::iterator (aka
+  // __hash_iterator<__node_pointer>)
+  auto hash_iter_sp = valobj_sp->GetChildMemberWithName("__i_");
+  if (!hash_iter_sp)
+    return lldb::ChildCacheState::eRefetch;
+
+  // Type is '__hash_iterator<__node_pointer>'
+  auto hash_iter_type = hash_iter_sp->GetCompilerType();
+  if (!hash_iter_type.IsValid())
+    return lldb::ChildCacheState::eRefetch;
+
+  // Type is '__node_pointer'
+  auto node_pointer_type = hash_iter_type.GetTypeTemplateArgument(0);
+  if (!node_pointer_type.IsValid())
+    return lldb::ChildCacheState::eRefetch;
+
+  // Cast the __hash_iterator to a __node_pointer (which stores our key/value
+  // pair)
+  auto hash_node_sp = hash_iter_sp->Cast(node_pointer_type);
+  if (!hash_node_sp)
+    return lldb::ChildCacheState::eRefetch;
+
+  auto key_value_sp = hash_node_sp->GetChildMemberWithName("__value_");
+  if (!key_value_sp) {
+    // clang-format off
+    // Since D101206 (ba79fb2e1f), libc++ wraps the `__value_` in an
+    // anonymous union.
+    // Child 0: __hash_node_base base class
+    // Child 1: __hash_
+    // Child 2: anonymous union
+    // clang-format on
+    auto anon_union_sp = hash_node_sp->GetChildAtIndex(2);
+    if (!anon_union_sp)
+      return lldb::ChildCacheState::eRefetch;
+
+    key_value_sp = anon_union_sp->GetChildMemberWithName("__value_");
+    if (!key_value_sp)
+      return lldb::ChildCacheState::eRefetch;
+  }
+
+  // Create the synthetic child, which is a pair where the key and value can be
+  // retrieved // by querying the synthetic frontend for
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labath wrote:

remove extra `//`

https://github.com/llvm/llvm-project/pull/97754