1 files changed, 112 insertions, 0 deletions
diff --git a/contrib/llvm-project/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp b/contrib/llvm-project/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp
new file mode 100644
index 000000000000..05199ba35b9a
--- /dev/null
+++ b/contrib/llvm-project/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp
@@ -0,0 +1,112 @@
+//===-- LibStdcppTuple.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "LibStdcpp.h"
+
+#include "lldb/Core/ValueObject.h"
+#include "lldb/DataFormatters/FormattersHelpers.h"
+#include "lldb/DataFormatters/TypeSynthetic.h"
+#include "lldb/Utility/ConstString.h"
+
+#include <memory>
+#include <vector>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::formatters;
+
+namespace {
+
+class LibStdcppTupleSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
+public:
+  explicit LibStdcppTupleSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
+
+  llvm::Expected<uint32_t> CalculateNumChildren() override;
+
+  lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
+
+  lldb::ChildCacheState Update() override;
+
+  bool MightHaveChildren() override;
+
+  size_t GetIndexOfChildWithName(ConstString name) override;
+
+private:
+  // The lifetime of a ValueObject and all its derivative ValueObjects
+  // (children, clones, etc.) is managed by a ClusterManager. These
+  // objects are only destroyed when every shared pointer to any of them
+  // is destroyed, so we must not store a shared pointer to any ValueObject
+  // derived from our backend ValueObject (since we're in the same cluster).
+  std::vector<ValueObject*> m_members;
+};
+
+} // end of anonymous namespace
+
+LibStdcppTupleSyntheticFrontEnd::LibStdcppTupleSyntheticFrontEnd(
+    lldb::ValueObjectSP valobj_sp)
+    : SyntheticChildrenFrontEnd(*valobj_sp) {
+  Update();
+}
+
+lldb::ChildCacheState LibStdcppTupleSyntheticFrontEnd::Update() {
+  m_members.clear();
+
+  ValueObjectSP valobj_backend_sp = m_backend.GetSP();
+  if (!valobj_backend_sp)
+    return lldb::ChildCacheState::eRefetch;
+
+  ValueObjectSP next_child_sp = valobj_backend_sp->GetNonSyntheticValue();
+  while (next_child_sp != nullptr) {
+    ValueObjectSP current_child = next_child_sp;
+    next_child_sp = nullptr;
+
+    size_t child_count = current_child->GetNumChildrenIgnoringErrors();
+    for (size_t i = 0; i < child_count; ++i) {
+      ValueObjectSP child_sp = current_child->GetChildAtIndex(i);
+      llvm::StringRef name_str = child_sp->GetName().GetStringRef();
+      if (name_str.starts_with("std::_Tuple_impl<")) {
+        next_child_sp = child_sp;
+      } else if (name_str.starts_with("std::_Head_base<")) {
+        ValueObjectSP value_sp =
+            child_sp->GetChildMemberWithName("_M_head_impl");
+        if (value_sp) {
+          StreamString name;
+          name.Printf("[%zd]", m_members.size());
+          m_members.push_back(value_sp->Clone(ConstString(name.GetString())).get());
+        }
+      }
+    }
+  }
+
+  return lldb::ChildCacheState::eRefetch;
+}
+
+bool LibStdcppTupleSyntheticFrontEnd::MightHaveChildren() { return true; }
+
+lldb::ValueObjectSP
+LibStdcppTupleSyntheticFrontEnd::GetChildAtIndex(uint32_t idx) {
+  if (idx < m_members.size() && m_members[idx])
+    return m_members[idx]->GetSP();
+  return lldb::ValueObjectSP();
+}
+
+llvm::Expected<uint32_t>
+LibStdcppTupleSyntheticFrontEnd::CalculateNumChildren() {
+  return m_members.size();
+}
+
+size_t LibStdcppTupleSyntheticFrontEnd::GetIndexOfChildWithName(
+    ConstString name) {
+  return ExtractIndexFromString(name.GetCString());
+}
+
+SyntheticChildrenFrontEnd *
+lldb_private::formatters::LibStdcppTupleSyntheticFrontEndCreator(
+    CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
+  return (valobj_sp ? new LibStdcppTupleSyntheticFrontEnd(valobj_sp) : nullptr);
+}