1 //===-- LibCxxAtomic.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 "LibCxxAtomic.h"
10 #include "lldb/DataFormatters/FormattersHelpers.h"
11
12 using namespace lldb;
13 using namespace lldb_private;
14 using namespace lldb_private::formatters;
15
16 //
17 // We are supporting two versions of libc++ std::atomic
18 //
19 // Given std::atomic<int> i;
20 //
21 // The previous version of std::atomic was laid out like this
22 //
23 // (lldb) frame var -L -R i
24 // 0x00007ffeefbff9a0: (std::__1::atomic<int>) i = {
25 // 0x00007ffeefbff9a0: std::__1::__atomic_base<int, true> = {
26 // 0x00007ffeefbff9a0: std::__1::__atomic_base<int, false> = {
27 // 0x00007ffeefbff9a0: __a_ = 5
28 // }
29 // }
30 // }
31 //
32 // In this case we need to obtain __a_ and the current version is laid out as so
33 //
34 // (lldb) frame var -L -R i
35 // 0x00007ffeefbff9b0: (std::__1::atomic<int>) i = {
36 // 0x00007ffeefbff9b0: std::__1::__atomic_base<int, true> = {
37 // 0x00007ffeefbff9b0: std::__1::__atomic_base<int, false> = {
38 // 0x00007ffeefbff9b0: __a_ = {
39 // 0x00007ffeefbff9b0: std::__1::__cxx_atomic_base_impl<int> = {
40 // 0x00007ffeefbff9b0: __a_value = 5
41 // }
42 // }
43 // }
44 // }
45 //}
46 //
47 // In this case we need to obtain __a_value
48 //
49 // The below method covers both cases and returns the relevant member as a
50 // ValueObjectSP
51 //
52 ValueObjectSP
GetLibCxxAtomicValue(ValueObject & valobj)53 lldb_private::formatters::GetLibCxxAtomicValue(ValueObject &valobj) {
54 ValueObjectSP non_sythetic = valobj.GetNonSyntheticValue();
55 if (!non_sythetic)
56 return {};
57
58 ValueObjectSP member__a_ = non_sythetic->GetChildMemberWithName("__a_");
59 if (!member__a_)
60 return {};
61
62 ValueObjectSP member__a_value =
63 member__a_->GetChildMemberWithName("__a_value");
64 if (!member__a_value)
65 return member__a_;
66
67 return member__a_value;
68 }
69
LibCxxAtomicSummaryProvider(ValueObject & valobj,Stream & stream,const TypeSummaryOptions & options)70 bool lldb_private::formatters::LibCxxAtomicSummaryProvider(
71 ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
72
73 if (ValueObjectSP atomic_value = GetLibCxxAtomicValue(valobj)) {
74 std::string summary;
75 if (atomic_value->GetSummaryAsCString(summary, options) &&
76 summary.size() > 0) {
77 stream.Printf("%s", summary.c_str());
78 return true;
79 }
80 }
81
82 return false;
83 }
84
85 namespace lldb_private {
86 namespace formatters {
87 class LibcxxStdAtomicSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
88 public:
89 LibcxxStdAtomicSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
90
91 ~LibcxxStdAtomicSyntheticFrontEnd() override = default;
92
93 llvm::Expected<uint32_t> CalculateNumChildren() override;
94
95 lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
96
97 lldb::ChildCacheState Update() override;
98
99 bool MightHaveChildren() override;
100
101 size_t GetIndexOfChildWithName(ConstString name) override;
102
103 private:
104 ValueObject *m_real_child = nullptr;
105 };
106 } // namespace formatters
107 } // namespace lldb_private
108
109 lldb_private::formatters::LibcxxStdAtomicSyntheticFrontEnd::
LibcxxStdAtomicSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)110 LibcxxStdAtomicSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
111 : SyntheticChildrenFrontEnd(*valobj_sp) {}
112
113 lldb::ChildCacheState
Update()114 lldb_private::formatters::LibcxxStdAtomicSyntheticFrontEnd::Update() {
115 ValueObjectSP atomic_value = GetLibCxxAtomicValue(m_backend);
116 if (atomic_value)
117 m_real_child = GetLibCxxAtomicValue(m_backend).get();
118
119 return lldb::ChildCacheState::eRefetch;
120 }
121
122 bool lldb_private::formatters::LibcxxStdAtomicSyntheticFrontEnd::
MightHaveChildren()123 MightHaveChildren() {
124 return true;
125 }
126
127 llvm::Expected<uint32_t> lldb_private::formatters::
CalculateNumChildren()128 LibcxxStdAtomicSyntheticFrontEnd::CalculateNumChildren() {
129 return m_real_child ? 1 : 0;
130 }
131
132 lldb::ValueObjectSP
GetChildAtIndex(uint32_t idx)133 lldb_private::formatters::LibcxxStdAtomicSyntheticFrontEnd::GetChildAtIndex(
134 uint32_t idx) {
135 if (idx == 0)
136 return m_real_child->GetSP()->Clone(ConstString("Value"));
137 return nullptr;
138 }
139
140 size_t lldb_private::formatters::LibcxxStdAtomicSyntheticFrontEnd::
GetIndexOfChildWithName(ConstString name)141 GetIndexOfChildWithName(ConstString name) {
142 return name == "Value" ? 0 : UINT32_MAX;
143 }
144
145 SyntheticChildrenFrontEnd *
LibcxxAtomicSyntheticFrontEndCreator(CXXSyntheticChildren *,lldb::ValueObjectSP valobj_sp)146 lldb_private::formatters::LibcxxAtomicSyntheticFrontEndCreator(
147 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
148 if (valobj_sp)
149 return new LibcxxStdAtomicSyntheticFrontEnd(valobj_sp);
150 return nullptr;
151 }
152