lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp

   1 //===-- LibStdcppTuple.cpp ------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "LibStdcpp.h"
  10
  11 #include "lldb/DataFormatters/FormattersHelpers.h"
  12 #include "lldb/DataFormatters/TypeSynthetic.h"
  13 #include "lldb/Utility/ConstString.h"
  14 #include "lldb/ValueObject/ValueObject.h"
  15
  16 #include <memory>
  17 #include <vector>
  18
  19 using namespace lldb;
  20 using namespace lldb_private;
  21 using namespace lldb_private::formatters;
  22
  23 namespace {
  24
  25 class LibStdcppTupleSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
  26 public:
  27   explicit LibStdcppTupleSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
  28
  29   llvm::Expected<uint32_t> CalculateNumChildren() override;
  30
  31   lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
  32
  33   lldb::ChildCacheState Update() override;
  34
  35   bool MightHaveChildren() override;
  36
  37   size_t GetIndexOfChildWithName(ConstString name) override;
  38
  39 private:
  40   // The lifetime of a ValueObject and all its derivative ValueObjects
  41   // (children, clones, etc.) is managed by a ClusterManager. These
  42   // objects are only destroyed when every shared pointer to any of them
  43   // is destroyed, so we must not store a shared pointer to any ValueObject
  44   // derived from our backend ValueObject (since we're in the same cluster).
  45   std::vector<ValueObject*> m_members;
  46 };
  47
  48 } // end of anonymous namespace
  49
  50 LibStdcppTupleSyntheticFrontEnd::LibStdcppTupleSyntheticFrontEnd(
  51     lldb::ValueObjectSP valobj_sp)
  52     : SyntheticChildrenFrontEnd(*valobj_sp) {
  53   Update();
  54 }
  55
  56 lldb::ChildCacheState LibStdcppTupleSyntheticFrontEnd::Update() {
  57   m_members.clear();
  58
  59   ValueObjectSP valobj_backend_sp = m_backend.GetSP();
  60   if (!valobj_backend_sp)
  61     return lldb::ChildCacheState::eRefetch;
  62
  63   ValueObjectSP next_child_sp = valobj_backend_sp->GetNonSyntheticValue();
  64   while (next_child_sp != nullptr) {
  65     ValueObjectSP current_child = next_child_sp;
  66     next_child_sp = nullptr;
  67
  68     size_t child_count = current_child->GetNumChildrenIgnoringErrors();
  69     for (size_t i = 0; i < child_count; ++i) {
  70       ValueObjectSP child_sp = current_child->GetChildAtIndex(i);
  71       llvm::StringRef name_str = child_sp->GetName().GetStringRef();
  72       if (name_str.starts_with("std::_Tuple_impl<")) {
  73         next_child_sp = child_sp;
  74       } else if (name_str.starts_with("std::_Head_base<")) {
  75         ValueObjectSP value_sp =
  76             child_sp->GetChildMemberWithName("_M_head_impl");
  77         if (value_sp) {
  78           StreamString name;
  79           name.Printf("[%zd]", m_members.size());
  80           m_members.push_back(value_sp->Clone(ConstString(name.GetString())).get());
  81         }
  82       }
  83     }
  84   }
  85
  86   return lldb::ChildCacheState::eRefetch;
  87 }
  88
  89 bool LibStdcppTupleSyntheticFrontEnd::MightHaveChildren() { return true; }
  90
  91 lldb::ValueObjectSP
  92 LibStdcppTupleSyntheticFrontEnd::GetChildAtIndex(uint32_t idx) {
  93   if (idx < m_members.size() && m_members[idx])
  94     return m_members[idx]->GetSP();
  95   return lldb::ValueObjectSP();
  96 }
  97
  98 llvm::Expected<uint32_t>
  99 LibStdcppTupleSyntheticFrontEnd::CalculateNumChildren() {
 100   return m_members.size();
 101 }
 102
 103 size_t LibStdcppTupleSyntheticFrontEnd::GetIndexOfChildWithName(
 104     ConstString name) {
 105   return ExtractIndexFromString(name.GetCString());
 106 }
 107
 108 SyntheticChildrenFrontEnd *
 109 lldb_private::formatters::LibStdcppTupleSyntheticFrontEndCreator(
 110     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
 111   return (valobj_sp ? new LibStdcppTupleSyntheticFrontEnd(valobj_sp) : nullptr);
 112 }