1//===-- LibCxxTuple.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 "LibCxx.h"
10#include "lldb/DataFormatters/FormattersHelpers.h"
11
12using namespace lldb;
13using namespace lldb_private;
14
15namespace {
16
17class TupleFrontEnd: public SyntheticChildrenFrontEnd {
18public:
19 TupleFrontEnd(ValueObject &valobj) : SyntheticChildrenFrontEnd(valobj) {
20 Update();
21 }
22
23 size_t GetIndexOfChildWithName(ConstString name) override {
24 return formatters::ExtractIndexFromString(item_name: name.GetCString());
25 }
26
27 bool MightHaveChildren() override { return true; }
28 lldb::ChildCacheState Update() override;
29 llvm::Expected<uint32_t> CalculateNumChildren() override {
30 return m_elements.size();
31 }
32 ValueObjectSP GetChildAtIndex(uint32_t idx) override;
33
34private:
35 // The lifetime of a ValueObject and all its derivative ValueObjects
36 // (children, clones, etc.) is managed by a ClusterManager. These
37 // objects are only destroyed when every shared pointer to any of them
38 // is destroyed, so we must not store a shared pointer to any ValueObject
39 // derived from our backend ValueObject (since we're in the same cluster).
40 std::vector<ValueObject*> m_elements;
41 ValueObject* m_base = nullptr;
42};
43}
44
45lldb::ChildCacheState TupleFrontEnd::Update() {
46 m_elements.clear();
47 m_base = nullptr;
48
49 ValueObjectSP base_sp;
50 base_sp = m_backend.GetChildMemberWithName(name: "__base_");
51 if (!base_sp) {
52 // Pre r304382 name of the base element.
53 base_sp = m_backend.GetChildMemberWithName(name: "base_");
54 }
55 if (!base_sp)
56 return lldb::ChildCacheState::eRefetch;
57 m_base = base_sp.get();
58 m_elements.assign(n: base_sp->GetCompilerType().GetNumDirectBaseClasses(),
59 val: nullptr);
60 return lldb::ChildCacheState::eRefetch;
61}
62
63ValueObjectSP TupleFrontEnd::GetChildAtIndex(uint32_t idx) {
64 if (idx >= m_elements.size())
65 return ValueObjectSP();
66 if (!m_base)
67 return ValueObjectSP();
68 if (m_elements[idx])
69 return m_elements[idx]->GetSP();
70
71 CompilerType holder_type =
72 m_base->GetCompilerType().GetDirectBaseClassAtIndex(idx, bit_offset_ptr: nullptr);
73 if (!holder_type)
74 return ValueObjectSP();
75 ValueObjectSP holder_sp = m_base->GetChildAtIndex(idx);
76 if (!holder_sp)
77 return ValueObjectSP();
78
79 ValueObjectSP elem_sp = holder_sp->GetChildAtIndex(idx: 0);
80 if (elem_sp)
81 m_elements[idx] =
82 elem_sp->Clone(new_name: ConstString(llvm::formatv(Fmt: "[{0}]", Vals&: idx).str())).get();
83
84 if (m_elements[idx])
85 return m_elements[idx]->GetSP();
86 return ValueObjectSP();
87}
88
89SyntheticChildrenFrontEnd *
90formatters::LibcxxTupleFrontEndCreator(CXXSyntheticChildren *,
91 lldb::ValueObjectSP valobj_sp) {
92 if (valobj_sp)
93 return new TupleFrontEnd(*valobj_sp);
94 return nullptr;
95}
96

source code of lldb/source/Plugins/Language/CPlusPlus/LibCxxTuple.cpp