1 //===-- LibCxxVector.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 "lldb/Core/ValueObject.h"
12 #include "lldb/DataFormatters/FormattersHelpers.h"
13 #include "lldb/Utility/ConstString.h"
14 
15 using namespace lldb;
16 using namespace lldb_private;
17 using namespace lldb_private::formatters;
18 
19 namespace lldb_private {
20 namespace formatters {
21 class LibcxxStdVectorSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
22 public:
23   LibcxxStdVectorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
24 
25   ~LibcxxStdVectorSyntheticFrontEnd() override;
26 
27   size_t CalculateNumChildren() override;
28 
29   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
30 
31   bool Update() override;
32 
33   bool MightHaveChildren() override;
34 
35   size_t GetIndexOfChildWithName(ConstString name) override;
36 
37 private:
38   ValueObject *m_start = nullptr;
39   ValueObject *m_finish = nullptr;
40   CompilerType m_element_type;
41   uint32_t m_element_size = 0;
42 };
43 
44 class LibcxxVectorBoolSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
45 public:
46   LibcxxVectorBoolSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
47 
48   size_t CalculateNumChildren() override;
49 
50   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
51 
52   bool Update() override;
53 
54   bool MightHaveChildren() override { return true; }
55 
56   size_t GetIndexOfChildWithName(ConstString name) override;
57 
58 private:
59   CompilerType m_bool_type;
60   ExecutionContextRef m_exe_ctx_ref;
61   uint64_t m_count = 0;
62   lldb::addr_t m_base_data_address = 0;
63   std::map<size_t, lldb::ValueObjectSP> m_children;
64 };
65 
66 } // namespace formatters
67 } // namespace lldb_private
68 
69 lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
70     LibcxxStdVectorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
71     : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type() {
72   if (valobj_sp)
73     Update();
74 }
75 
76 lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
77     ~LibcxxStdVectorSyntheticFrontEnd() {
78   // these need to stay around because they are child objects who will follow
79   // their parent's life cycle
80   // delete m_start;
81   // delete m_finish;
82 }
83 
84 size_t lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
85     CalculateNumChildren() {
86   if (!m_start || !m_finish)
87     return 0;
88   uint64_t start_val = m_start->GetValueAsUnsigned(0);
89   uint64_t finish_val = m_finish->GetValueAsUnsigned(0);
90 
91   if (start_val == 0 || finish_val == 0)
92     return 0;
93 
94   if (start_val >= finish_val)
95     return 0;
96 
97   size_t num_children = (finish_val - start_val);
98   if (num_children % m_element_size)
99     return 0;
100   return num_children / m_element_size;
101 }
102 
103 lldb::ValueObjectSP
104 lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::GetChildAtIndex(
105     size_t idx) {
106   if (!m_start || !m_finish)
107     return lldb::ValueObjectSP();
108 
109   uint64_t offset = idx * m_element_size;
110   offset = offset + m_start->GetValueAsUnsigned(0);
111   StreamString name;
112   name.Printf("[%" PRIu64 "]", (uint64_t)idx);
113   return CreateValueObjectFromAddress(name.GetString(), offset,
114                                       m_backend.GetExecutionContextRef(),
115                                       m_element_type);
116 }
117 
118 bool lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::Update() {
119   m_start = m_finish = nullptr;
120   ValueObjectSP data_type_finder_sp(
121       m_backend.GetChildMemberWithName(ConstString("__end_cap_"), true));
122   if (!data_type_finder_sp)
123     return false;
124 
125   switch (data_type_finder_sp->GetCompilerType().GetNumDirectBaseClasses()) {
126   case 1:
127     // Assume a pre llvm r300140 __compressed_pair implementation:
128     data_type_finder_sp = data_type_finder_sp->GetChildMemberWithName(
129       ConstString("__first_"), true);
130     break;
131   case 2: {
132     // Assume a post llvm r300140 __compressed_pair implementation:
133     ValueObjectSP first_elem_parent_sp =
134       data_type_finder_sp->GetChildAtIndex(0, true);
135     data_type_finder_sp = first_elem_parent_sp->GetChildMemberWithName(
136       ConstString("__value_"), true);
137     break;
138   }
139   default:
140     return false;
141   }
142 
143   if (!data_type_finder_sp)
144     return false;
145   m_element_type = data_type_finder_sp->GetCompilerType().GetPointeeType();
146   if (llvm::Optional<uint64_t> size = m_element_type.GetByteSize(nullptr)) {
147     m_element_size = *size;
148 
149     if (m_element_size > 0) {
150       // store raw pointers or end up with a circular dependency
151       m_start =
152           m_backend.GetChildMemberWithName(ConstString("__begin_"), true).get();
153       m_finish =
154           m_backend.GetChildMemberWithName(ConstString("__end_"), true).get();
155     }
156   }
157   return false;
158 }
159 
160 bool lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
161     MightHaveChildren() {
162   return true;
163 }
164 
165 size_t lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
166     GetIndexOfChildWithName(ConstString name) {
167   if (!m_start || !m_finish)
168     return UINT32_MAX;
169   return ExtractIndexFromString(name.GetCString());
170 }
171 
172 lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
173     LibcxxVectorBoolSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
174     : SyntheticChildrenFrontEnd(*valobj_sp), m_bool_type(), m_exe_ctx_ref(),
175       m_children() {
176   if (valobj_sp) {
177     Update();
178     m_bool_type =
179         valobj_sp->GetCompilerType().GetBasicTypeFromAST(lldb::eBasicTypeBool);
180   }
181 }
182 
183 size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
184     CalculateNumChildren() {
185   return m_count;
186 }
187 
188 lldb::ValueObjectSP
189 lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::GetChildAtIndex(
190     size_t idx) {
191   auto iter = m_children.find(idx), end = m_children.end();
192   if (iter != end)
193     return iter->second;
194   if (idx >= m_count)
195     return {};
196   if (m_base_data_address == 0 || m_count == 0)
197     return {};
198   if (!m_bool_type)
199     return {};
200   size_t byte_idx = (idx >> 3); // divide by 8 to get byte index
201   size_t bit_index = (idx & 7); // efficient idx % 8 for bit index
202   lldb::addr_t byte_location = m_base_data_address + byte_idx;
203   ProcessSP process_sp(m_exe_ctx_ref.GetProcessSP());
204   if (!process_sp)
205     return {};
206   uint8_t byte = 0;
207   uint8_t mask = 0;
208   Status err;
209   size_t bytes_read = process_sp->ReadMemory(byte_location, &byte, 1, err);
210   if (err.Fail() || bytes_read == 0)
211     return {};
212   mask = 1 << bit_index;
213   bool bit_set = ((byte & mask) != 0);
214   llvm::Optional<uint64_t> size = m_bool_type.GetByteSize(nullptr);
215   if (!size)
216     return {};
217   WritableDataBufferSP buffer_sp(new DataBufferHeap(*size, 0));
218   if (bit_set && buffer_sp && buffer_sp->GetBytes()) {
219     // regardless of endianness, anything non-zero is true
220     *(buffer_sp->GetBytes()) = 1;
221   }
222   StreamString name;
223   name.Printf("[%" PRIu64 "]", (uint64_t)idx);
224   ValueObjectSP retval_sp(CreateValueObjectFromData(
225       name.GetString(),
226       DataExtractor(buffer_sp, process_sp->GetByteOrder(),
227                     process_sp->GetAddressByteSize()),
228       m_exe_ctx_ref, m_bool_type));
229   if (retval_sp)
230     m_children[idx] = retval_sp;
231   return retval_sp;
232 }
233 
234 /*(std::__1::vector<std::__1::allocator<bool> >) vBool = {
235  __begin_ = 0x00000001001000e0
236  __size_ = 56
237  __cap_alloc_ = {
238  std::__1::__libcpp_compressed_pair_imp<unsigned long,
239  std::__1::allocator<unsigned long> > = {
240  __first_ = 1
241  }
242  }
243  }*/
244 
245 bool lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::Update() {
246   m_children.clear();
247   ValueObjectSP valobj_sp = m_backend.GetSP();
248   if (!valobj_sp)
249     return false;
250   m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
251   ValueObjectSP size_sp(
252       valobj_sp->GetChildMemberWithName(ConstString("__size_"), true));
253   if (!size_sp)
254     return false;
255   m_count = size_sp->GetValueAsUnsigned(0);
256   if (!m_count)
257     return true;
258   ValueObjectSP begin_sp(
259       valobj_sp->GetChildMemberWithName(ConstString("__begin_"), true));
260   if (!begin_sp) {
261     m_count = 0;
262     return false;
263   }
264   m_base_data_address = begin_sp->GetValueAsUnsigned(0);
265   if (!m_base_data_address) {
266     m_count = 0;
267     return false;
268   }
269   return false;
270 }
271 
272 size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
273     GetIndexOfChildWithName(ConstString name) {
274   if (!m_count || !m_base_data_address)
275     return UINT32_MAX;
276   const char *item_name = name.GetCString();
277   uint32_t idx = ExtractIndexFromString(item_name);
278   if (idx < UINT32_MAX && idx >= CalculateNumChildren())
279     return UINT32_MAX;
280   return idx;
281 }
282 
283 lldb_private::SyntheticChildrenFrontEnd *
284 lldb_private::formatters::LibcxxStdVectorSyntheticFrontEndCreator(
285     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
286   if (!valobj_sp)
287     return nullptr;
288   CompilerType type = valobj_sp->GetCompilerType();
289   if (!type.IsValid() || type.GetNumTemplateArguments() == 0)
290     return nullptr;
291   CompilerType arg_type = type.GetTypeTemplateArgument(0);
292   if (arg_type.GetTypeName() == "bool")
293     return new LibcxxVectorBoolSyntheticFrontEnd(valobj_sp);
294   return new LibcxxStdVectorSyntheticFrontEnd(valobj_sp);
295 }
296