lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp

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