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