1 //===-- LibCxxVector.cpp ----------------------------------------*- C++ -*-===//
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;
39   ValueObject *m_finish;
40   CompilerType m_element_type;
41   uint32_t m_element_size;
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;
62   lldb::addr_t m_base_data_address;
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_start(nullptr),
72       m_finish(nullptr), m_element_type(), m_element_size(0) {
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(ConstString("__end_cap_"), true));
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 = data_type_finder_sp->GetChildMemberWithName(
130       ConstString("__first_"), true);
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, true);
136     data_type_finder_sp = first_elem_parent_sp->GetChildMemberWithName(
137       ConstString("__value_"), true);
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 (llvm::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 =
153           m_backend.GetChildMemberWithName(ConstString("__begin_"), true).get();
154       m_finish =
155           m_backend.GetChildMemberWithName(ConstString("__end_"), true).get();
156     }
157   }
158   return false;
159 }
160 
161 bool lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
162     MightHaveChildren() {
163   return true;
164 }
165 
166 size_t lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
167     GetIndexOfChildWithName(ConstString name) {
168   if (!m_start || !m_finish)
169     return UINT32_MAX;
170   return ExtractIndexFromString(name.GetCString());
171 }
172 
173 lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
174     LibcxxVectorBoolSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
175     : SyntheticChildrenFrontEnd(*valobj_sp), m_bool_type(), m_exe_ctx_ref(),
176       m_count(0), m_base_data_address(0), m_children() {
177   if (valobj_sp) {
178     Update();
179     m_bool_type =
180         valobj_sp->GetCompilerType().GetBasicTypeFromAST(lldb::eBasicTypeBool);
181   }
182 }
183 
184 size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
185     CalculateNumChildren() {
186   return m_count;
187 }
188 
189 lldb::ValueObjectSP
190 lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::GetChildAtIndex(
191     size_t idx) {
192   auto iter = m_children.find(idx), end = m_children.end();
193   if (iter != end)
194     return iter->second;
195   if (idx >= m_count)
196     return {};
197   if (m_base_data_address == 0 || m_count == 0)
198     return {};
199   if (!m_bool_type)
200     return {};
201   size_t byte_idx = (idx >> 3); // divide by 8 to get byte index
202   size_t bit_index = (idx & 7); // efficient idx % 8 for bit index
203   lldb::addr_t byte_location = m_base_data_address + byte_idx;
204   ProcessSP process_sp(m_exe_ctx_ref.GetProcessSP());
205   if (!process_sp)
206     return {};
207   uint8_t byte = 0;
208   uint8_t mask = 0;
209   Status err;
210   size_t bytes_read = process_sp->ReadMemory(byte_location, &byte, 1, err);
211   if (err.Fail() || bytes_read == 0)
212     return {};
213   mask = 1 << bit_index;
214   bool bit_set = ((byte & mask) != 0);
215   llvm::Optional<uint64_t> size = m_bool_type.GetByteSize(nullptr);
216   if (!size)
217     return {};
218   DataBufferSP buffer_sp(new DataBufferHeap(*size, 0));
219   if (bit_set && buffer_sp && buffer_sp->GetBytes()) {
220     // regardless of endianness, anything non-zero is true
221     *(buffer_sp->GetBytes()) = 1;
222   }
223   StreamString name;
224   name.Printf("[%" PRIu64 "]", (uint64_t)idx);
225   ValueObjectSP retval_sp(CreateValueObjectFromData(
226       name.GetString(),
227       DataExtractor(buffer_sp, process_sp->GetByteOrder(),
228                     process_sp->GetAddressByteSize()),
229       m_exe_ctx_ref, m_bool_type));
230   if (retval_sp)
231     m_children[idx] = retval_sp;
232   return retval_sp;
233 }
234 
235 /*(std::__1::vector<std::__1::allocator<bool> >) vBool = {
236  __begin_ = 0x00000001001000e0
237  __size_ = 56
238  __cap_alloc_ = {
239  std::__1::__libcpp_compressed_pair_imp<unsigned long,
240  std::__1::allocator<unsigned long> > = {
241  __first_ = 1
242  }
243  }
244  }*/
245 
246 bool lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::Update() {
247   m_children.clear();
248   ValueObjectSP valobj_sp = m_backend.GetSP();
249   if (!valobj_sp)
250     return false;
251   m_exe_ctx_ref = valobj_sp->GetExecutionContextRef();
252   ValueObjectSP size_sp(
253       valobj_sp->GetChildMemberWithName(ConstString("__size_"), true));
254   if (!size_sp)
255     return false;
256   m_count = size_sp->GetValueAsUnsigned(0);
257   if (!m_count)
258     return true;
259   ValueObjectSP begin_sp(
260       valobj_sp->GetChildMemberWithName(ConstString("__begin_"), true));
261   if (!begin_sp) {
262     m_count = 0;
263     return false;
264   }
265   m_base_data_address = begin_sp->GetValueAsUnsigned(0);
266   if (!m_base_data_address) {
267     m_count = 0;
268     return false;
269   }
270   return false;
271 }
272 
273 size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
274     GetIndexOfChildWithName(ConstString name) {
275   if (!m_count || !m_base_data_address)
276     return UINT32_MAX;
277   const char *item_name = name.GetCString();
278   uint32_t idx = ExtractIndexFromString(item_name);
279   if (idx < UINT32_MAX && idx >= CalculateNumChildren())
280     return UINT32_MAX;
281   return idx;
282 }
283 
284 lldb_private::SyntheticChildrenFrontEnd *
285 lldb_private::formatters::LibcxxStdVectorSyntheticFrontEndCreator(
286     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
287   if (!valobj_sp)
288     return nullptr;
289   CompilerType type = valobj_sp->GetCompilerType();
290   if (!type.IsValid() || type.GetNumTemplateArguments() == 0)
291     return nullptr;
292   CompilerType arg_type = type.GetTypeTemplateArgument(0);
293   if (arg_type.GetTypeName() == "bool")
294     return new LibcxxVectorBoolSyntheticFrontEnd(valobj_sp);
295   return new LibcxxStdVectorSyntheticFrontEnd(valobj_sp);
296 }
297