1 //===-- LibCxxUnorderedMap.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
11 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
12 #include "lldb/Core/ValueObject.h"
13 #include "lldb/Core/ValueObjectConstResult.h"
14 #include "lldb/DataFormatters/FormattersHelpers.h"
15 #include "lldb/Target/Target.h"
16 #include "lldb/Utility/ConstString.h"
17 #include "lldb/Utility/DataBufferHeap.h"
18 #include "lldb/Utility/Endian.h"
19 #include "lldb/Utility/Status.h"
20 #include "lldb/Utility/Stream.h"
21 #include "llvm/ADT/StringRef.h"
22
23 using namespace lldb;
24 using namespace lldb_private;
25 using namespace lldb_private::formatters;
26
27 namespace lldb_private {
28 namespace formatters {
29 class LibcxxStdUnorderedMapSyntheticFrontEnd
30 : public SyntheticChildrenFrontEnd {
31 public:
32 LibcxxStdUnorderedMapSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
33
34 ~LibcxxStdUnorderedMapSyntheticFrontEnd() override = default;
35
36 size_t CalculateNumChildren() override;
37
38 lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
39
40 bool Update() override;
41
42 bool MightHaveChildren() override;
43
44 size_t GetIndexOfChildWithName(ConstString name) override;
45
46 private:
47 CompilerType m_element_type;
48 CompilerType m_node_type;
49 ValueObject *m_tree = nullptr;
50 size_t m_num_elements = 0;
51 ValueObject *m_next_element = nullptr;
52 std::vector<std::pair<ValueObject *, uint64_t>> m_elements_cache;
53 };
54 } // namespace formatters
55 } // namespace lldb_private
56
57 lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
LibcxxStdUnorderedMapSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)58 LibcxxStdUnorderedMapSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
59 : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type(),
60 m_elements_cache() {
61 if (valobj_sp)
62 Update();
63 }
64
65 size_t lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
CalculateNumChildren()66 CalculateNumChildren() {
67 return m_num_elements;
68 }
69
consumeInlineNamespace(llvm::StringRef & name)70 static void consumeInlineNamespace(llvm::StringRef &name) {
71 // Delete past an inline namespace, if any: __[a-zA-Z0-9_]+::
72 auto scratch = name;
73 if (scratch.consume_front("__") && std::isalnum(scratch[0])) {
74 scratch = scratch.drop_while([](char c) { return std::isalnum(c); });
75 if (scratch.consume_front("::")) {
76 // Successfully consumed a namespace.
77 name = scratch;
78 }
79 }
80 }
81
isStdTemplate(ConstString type_name,llvm::StringRef type)82 static bool isStdTemplate(ConstString type_name, llvm::StringRef type) {
83 llvm::StringRef name = type_name.GetStringRef();
84 // The type name may be prefixed with `std::__<inline-namespace>::`.
85 if (name.consume_front("std::"))
86 consumeInlineNamespace(name);
87 return name.consume_front(type) && name.startswith("<");
88 }
89
isUnorderedMap(ConstString type_name)90 static bool isUnorderedMap(ConstString type_name) {
91 return isStdTemplate(type_name, "unordered_map") ||
92 isStdTemplate(type_name, "unordered_multimap");
93 }
94
95 lldb::ValueObjectSP lldb_private::formatters::
GetChildAtIndex(size_t idx)96 LibcxxStdUnorderedMapSyntheticFrontEnd::GetChildAtIndex(size_t idx) {
97 if (idx >= CalculateNumChildren())
98 return lldb::ValueObjectSP();
99 if (m_tree == nullptr)
100 return lldb::ValueObjectSP();
101
102 while (idx >= m_elements_cache.size()) {
103 if (m_next_element == nullptr)
104 return lldb::ValueObjectSP();
105
106 Status error;
107 ValueObjectSP node_sp = m_next_element->Dereference(error);
108 if (!node_sp || error.Fail())
109 return lldb::ValueObjectSP();
110
111 ValueObjectSP value_sp =
112 node_sp->GetChildMemberWithName(ConstString("__value_"), true);
113 ValueObjectSP hash_sp =
114 node_sp->GetChildMemberWithName(ConstString("__hash_"), true);
115 if (!hash_sp || !value_sp) {
116 if (!m_element_type) {
117 auto p1_sp = m_backend.GetChildAtNamePath({ConstString("__table_"),
118 ConstString("__p1_")});
119 if (!p1_sp)
120 return nullptr;
121
122 ValueObjectSP first_sp = nullptr;
123 switch (p1_sp->GetCompilerType().GetNumDirectBaseClasses()) {
124 case 1:
125 // Assume a pre llvm r300140 __compressed_pair implementation:
126 first_sp = p1_sp->GetChildMemberWithName(ConstString("__first_"),
127 true);
128 break;
129 case 2: {
130 // Assume a post llvm r300140 __compressed_pair implementation:
131 ValueObjectSP first_elem_parent_sp =
132 p1_sp->GetChildAtIndex(0, true);
133 first_sp = p1_sp->GetChildMemberWithName(ConstString("__value_"),
134 true);
135 break;
136 }
137 default:
138 return nullptr;
139 }
140
141 if (!first_sp)
142 return nullptr;
143 m_element_type = first_sp->GetCompilerType();
144 m_element_type = m_element_type.GetTypeTemplateArgument(0);
145 m_element_type = m_element_type.GetPointeeType();
146 m_node_type = m_element_type;
147 m_element_type = m_element_type.GetTypeTemplateArgument(0);
148 // This synthetic provider is used for both unordered_(multi)map and
149 // unordered_(multi)set. For unordered_map, the element type has an
150 // additional type layer, an internal struct (`__hash_value_type`)
151 // that wraps a std::pair. Peel away the internal wrapper type - whose
152 // structure is of no value to users, to expose the std::pair. This
153 // matches the structure returned by the std::map synthetic provider.
154 if (isUnorderedMap(m_backend.GetTypeName())) {
155 std::string name;
156 CompilerType field_type = m_element_type.GetFieldAtIndex(
157 0, name, nullptr, nullptr, nullptr);
158 CompilerType actual_type = field_type.GetTypedefedType();
159 if (isStdTemplate(actual_type.GetTypeName(), "pair"))
160 m_element_type = actual_type;
161 }
162 }
163 if (!m_node_type)
164 return nullptr;
165 node_sp = node_sp->Cast(m_node_type);
166 value_sp = node_sp->GetChildMemberWithName(ConstString("__value_"), true);
167 hash_sp = node_sp->GetChildMemberWithName(ConstString("__hash_"), true);
168 if (!value_sp || !hash_sp)
169 return nullptr;
170 }
171 m_elements_cache.push_back(
172 {value_sp.get(), hash_sp->GetValueAsUnsigned(0)});
173 m_next_element =
174 node_sp->GetChildMemberWithName(ConstString("__next_"), true).get();
175 if (!m_next_element || m_next_element->GetValueAsUnsigned(0) == 0)
176 m_next_element = nullptr;
177 }
178
179 std::pair<ValueObject *, uint64_t> val_hash = m_elements_cache[idx];
180 if (!val_hash.first)
181 return lldb::ValueObjectSP();
182 StreamString stream;
183 stream.Printf("[%" PRIu64 "]", (uint64_t)idx);
184 DataExtractor data;
185 Status error;
186 val_hash.first->GetData(data, error);
187 if (error.Fail())
188 return lldb::ValueObjectSP();
189 const bool thread_and_frame_only_if_stopped = true;
190 ExecutionContext exe_ctx = val_hash.first->GetExecutionContextRef().Lock(
191 thread_and_frame_only_if_stopped);
192 return CreateValueObjectFromData(stream.GetString(), data, exe_ctx,
193 m_element_type);
194 }
195
196 bool lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
Update()197 Update() {
198 m_num_elements = 0;
199 m_next_element = nullptr;
200 m_elements_cache.clear();
201 ValueObjectSP table_sp =
202 m_backend.GetChildMemberWithName(ConstString("__table_"), true);
203 if (!table_sp)
204 return false;
205
206 ValueObjectSP p2_sp = table_sp->GetChildMemberWithName(
207 ConstString("__p2_"), true);
208 ValueObjectSP num_elements_sp = nullptr;
209 llvm::SmallVector<ConstString, 3> next_path;
210 switch (p2_sp->GetCompilerType().GetNumDirectBaseClasses()) {
211 case 1:
212 // Assume a pre llvm r300140 __compressed_pair implementation:
213 num_elements_sp = p2_sp->GetChildMemberWithName(
214 ConstString("__first_"), true);
215 next_path.append({ConstString("__p1_"), ConstString("__first_"),
216 ConstString("__next_")});
217 break;
218 case 2: {
219 // Assume a post llvm r300140 __compressed_pair implementation:
220 ValueObjectSP first_elem_parent = p2_sp->GetChildAtIndex(0, true);
221 num_elements_sp = first_elem_parent->GetChildMemberWithName(
222 ConstString("__value_"), true);
223 next_path.append({ConstString("__p1_"), ConstString("__value_"),
224 ConstString("__next_")});
225 break;
226 }
227 default:
228 return false;
229 }
230
231 if (!num_elements_sp)
232 return false;
233
234 m_tree = table_sp->GetChildAtNamePath(next_path).get();
235 if (m_tree == nullptr)
236 return false;
237
238 m_num_elements = num_elements_sp->GetValueAsUnsigned(0);
239
240 if (m_num_elements > 0)
241 m_next_element =
242 table_sp->GetChildAtNamePath(next_path).get();
243 return false;
244 }
245
246 bool lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
MightHaveChildren()247 MightHaveChildren() {
248 return true;
249 }
250
251 size_t lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEnd::
GetIndexOfChildWithName(ConstString name)252 GetIndexOfChildWithName(ConstString name) {
253 return ExtractIndexFromString(name.GetCString());
254 }
255
256 SyntheticChildrenFrontEnd *
LibcxxStdUnorderedMapSyntheticFrontEndCreator(CXXSyntheticChildren *,lldb::ValueObjectSP valobj_sp)257 lldb_private::formatters::LibcxxStdUnorderedMapSyntheticFrontEndCreator(
258 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
259 return (valobj_sp ? new LibcxxStdUnorderedMapSyntheticFrontEnd(valobj_sp)
260 : nullptr);
261 }
262