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
12 using namespace lldb;
13 using namespace lldb_private;
14
15 namespace {
16
17 class TupleFrontEnd: public SyntheticChildrenFrontEnd {
18 public:
TupleFrontEnd(ValueObject & valobj)19 TupleFrontEnd(ValueObject &valobj) : SyntheticChildrenFrontEnd(valobj) {
20 Update();
21 }
22
GetIndexOfChildWithName(ConstString name)23 llvm::Expected<size_t> GetIndexOfChildWithName(ConstString name) override {
24 auto optional_idx = formatters::ExtractIndexFromString(name.GetCString());
25 if (!optional_idx) {
26 return llvm::createStringError("Type has no child named '%s'",
27 name.AsCString());
28 }
29 return *optional_idx;
30 }
31
32 lldb::ChildCacheState Update() override;
CalculateNumChildren()33 llvm::Expected<uint32_t> CalculateNumChildren() override {
34 return m_elements.size();
35 }
36 ValueObjectSP GetChildAtIndex(uint32_t idx) override;
37
38 private:
39 // The lifetime of a ValueObject and all its derivative ValueObjects
40 // (children, clones, etc.) is managed by a ClusterManager. These
41 // objects are only destroyed when every shared pointer to any of them
42 // is destroyed, so we must not store a shared pointer to any ValueObject
43 // derived from our backend ValueObject (since we're in the same cluster).
44 std::vector<ValueObject*> m_elements;
45 ValueObject* m_base = nullptr;
46 };
47 }
48
Update()49 lldb::ChildCacheState TupleFrontEnd::Update() {
50 m_elements.clear();
51 m_base = nullptr;
52
53 ValueObjectSP base_sp;
54 base_sp = m_backend.GetChildMemberWithName("__base_");
55 if (!base_sp) {
56 // Pre r304382 name of the base element.
57 base_sp = m_backend.GetChildMemberWithName("base_");
58 }
59 if (!base_sp)
60 return lldb::ChildCacheState::eRefetch;
61 m_base = base_sp.get();
62 m_elements.assign(base_sp->GetCompilerType().GetNumDirectBaseClasses(),
63 nullptr);
64 return lldb::ChildCacheState::eRefetch;
65 }
66
GetChildAtIndex(uint32_t idx)67 ValueObjectSP TupleFrontEnd::GetChildAtIndex(uint32_t idx) {
68 if (idx >= m_elements.size())
69 return ValueObjectSP();
70 if (!m_base)
71 return ValueObjectSP();
72 if (m_elements[idx])
73 return m_elements[idx]->GetSP();
74
75 CompilerType holder_type =
76 m_base->GetCompilerType().GetDirectBaseClassAtIndex(idx, nullptr);
77 if (!holder_type)
78 return ValueObjectSP();
79 ValueObjectSP holder_sp = m_base->GetChildAtIndex(idx);
80 if (!holder_sp)
81 return ValueObjectSP();
82
83 ValueObjectSP elem_sp = holder_sp->GetChildAtIndex(0);
84 if (elem_sp)
85 m_elements[idx] =
86 elem_sp->Clone(ConstString(llvm::formatv("[{0}]", idx).str())).get();
87
88 if (m_elements[idx])
89 return m_elements[idx]->GetSP();
90 return ValueObjectSP();
91 }
92
93 SyntheticChildrenFrontEnd *
LibcxxTupleFrontEndCreator(CXXSyntheticChildren *,lldb::ValueObjectSP valobj_sp)94 formatters::LibcxxTupleFrontEndCreator(CXXSyntheticChildren *,
95 lldb::ValueObjectSP valobj_sp) {
96 if (valobj_sp)
97 return new TupleFrontEnd(*valobj_sp);
98 return nullptr;
99 }
100