lldb/source/ValueObject/ValueObjectChild.cpp

   1 //===-- ValueObjectChild.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 "lldb/ValueObject/ValueObjectChild.h"
  10
  11 #include "lldb/Core/Value.h"
  12 #include "lldb/Symbol/CompilerType.h"
  13 #include "lldb/Target/ExecutionContext.h"
  14 #include "lldb/Target/Process.h"
  15 #include "lldb/Utility/Flags.h"
  16 #include "lldb/Utility/Scalar.h"
  17 #include "lldb/Utility/Status.h"
  18 #include "lldb/lldb-forward.h"
  19
  20 #include <functional>
  21 #include <memory>
  22 #include <vector>
  23
  24 #include <cstdio>
  25 #include <cstring>
  26
  27 using namespace lldb_private;
  28
  29 ValueObjectChild::ValueObjectChild(
  30     ValueObject &parent, const CompilerType &compiler_type, ConstString name,
  31     uint64_t byte_size, int32_t byte_offset, uint32_t bitfield_bit_size,
  32     uint32_t bitfield_bit_offset, bool is_base_class, bool is_deref_of_parent,
  33     AddressType child_ptr_or_ref_addr_type, uint64_t language_flags)
  34     : ValueObject(parent), m_compiler_type(compiler_type),
  35       m_byte_size(byte_size), m_byte_offset(byte_offset),
  36       m_bitfield_bit_size(bitfield_bit_size),
  37       m_bitfield_bit_offset(bitfield_bit_offset),
  38       m_is_base_class(is_base_class), m_is_deref_of_parent(is_deref_of_parent),
  39       m_can_update_with_invalid_exe_ctx() {
  40   m_name = name;
  41   SetAddressTypeOfChildren(child_ptr_or_ref_addr_type);
  42   SetLanguageFlags(language_flags);
  43 }
  44
  45 ValueObjectChild::~ValueObjectChild() = default;
  46
  47 lldb::ValueType ValueObjectChild::GetValueType() const {
  48   return m_parent->GetValueType();
  49 }
  50
  51 llvm::Expected<uint32_t> ValueObjectChild::CalculateNumChildren(uint32_t max) {
  52   ExecutionContext exe_ctx(GetExecutionContextRef());
  53   auto children_count = GetCompilerType().GetNumChildren(true, &exe_ctx);
  54   if (!children_count)
  55     return children_count;
  56   return *children_count <= max ? *children_count : max;
  57 }
  58
  59 static void AdjustForBitfieldness(ConstString &name,
  60                                   uint8_t bitfield_bit_size) {
  61   if (name && bitfield_bit_size)
  62     name.SetString(llvm::formatv("{0}:{1}", name, bitfield_bit_size).str());
  63 }
  64
  65 ConstString ValueObjectChild::GetTypeName() {
  66   if (m_type_name.IsEmpty()) {
  67     m_type_name = GetCompilerType().GetTypeName();
  68     AdjustForBitfieldness(m_type_name, m_bitfield_bit_size);
  69   }
  70   return m_type_name;
  71 }
  72
  73 ConstString ValueObjectChild::GetQualifiedTypeName() {
  74   ConstString qualified_name = GetCompilerType().GetTypeName();
  75   AdjustForBitfieldness(qualified_name, m_bitfield_bit_size);
  76   return qualified_name;
  77 }
  78
  79 ConstString ValueObjectChild::GetDisplayTypeName() {
  80   ConstString display_name = GetCompilerType().GetDisplayTypeName();
  81   AdjustForBitfieldness(display_name, m_bitfield_bit_size);
  82   return display_name;
  83 }
  84
  85 LazyBool ValueObjectChild::CanUpdateWithInvalidExecutionContext() {
  86   if (m_can_update_with_invalid_exe_ctx)
  87     return *m_can_update_with_invalid_exe_ctx;
  88   if (m_parent) {
  89     ValueObject *opinionated_parent =
  90         m_parent->FollowParentChain([](ValueObject *valobj) -> bool {
  91           return (valobj->CanUpdateWithInvalidExecutionContext() ==
  92                   eLazyBoolCalculate);
  93         });
  94     if (opinionated_parent)
  95       return *(m_can_update_with_invalid_exe_ctx =
  96                    opinionated_parent->CanUpdateWithInvalidExecutionContext());
  97   }
  98   return *(m_can_update_with_invalid_exe_ctx =
  99                this->ValueObject::CanUpdateWithInvalidExecutionContext());
 100 }
 101
 102 bool ValueObjectChild::UpdateValue() {
 103   m_error.Clear();
 104   SetValueIsValid(false);
 105   ValueObject *parent = m_parent;
 106   if (parent) {
 107     if (parent->UpdateValueIfNeeded(false)) {
 108       m_value.SetCompilerType(GetCompilerType());
 109
 110       CompilerType parent_type(parent->GetCompilerType());
 111       // Copy the parent scalar value and the scalar value type
 112       m_value.GetScalar() = parent->GetValue().GetScalar();
 113       m_value.SetValueType(parent->GetValue().GetValueType());
 114
 115       Flags parent_type_flags(parent_type.GetTypeInfo());
 116       const bool is_instance_ptr_base =
 117           ((m_is_base_class) &&
 118            (parent_type_flags.AnySet(lldb::eTypeInstanceIsPointer)));
 119
 120       if (parent->GetCompilerType().ShouldTreatScalarValueAsAddress()) {
 121         m_value.GetScalar() = parent->GetPointerValue();
 122
 123         switch (parent->GetAddressTypeOfChildren()) {
 124         case eAddressTypeFile: {
 125           lldb::ProcessSP process_sp(GetProcessSP());
 126           if (process_sp && process_sp->IsAlive())
 127             m_value.SetValueType(Value::ValueType::LoadAddress);
 128           else
 129             m_value.SetValueType(Value::ValueType::FileAddress);
 130         } break;
 131         case eAddressTypeLoad:
 132           m_value.SetValueType(is_instance_ptr_base
 133                                    ? Value::ValueType::Scalar
 134                                    : Value::ValueType::LoadAddress);
 135           break;
 136         case eAddressTypeHost:
 137           m_value.SetValueType(Value::ValueType::HostAddress);
 138           break;
 139         case eAddressTypeInvalid:
 140           // TODO: does this make sense?
 141           m_value.SetValueType(Value::ValueType::Scalar);
 142           break;
 143         }
 144       }
 145       switch (m_value.GetValueType()) {
 146       case Value::ValueType::Invalid:
 147         break;
 148       case Value::ValueType::LoadAddress:
 149       case Value::ValueType::FileAddress:
 150       case Value::ValueType::HostAddress: {
 151         lldb::addr_t addr = m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
 152         if (addr == LLDB_INVALID_ADDRESS) {
 153           m_error = Status::FromErrorString("parent address is invalid.");
 154         } else if (addr == 0) {
 155           m_error = Status::FromErrorString("parent is NULL");
 156         } else {
 157           // If a bitfield doesn't fit into the child_byte_size'd window at
 158           // child_byte_offset, move the window forward until it fits.  The
 159           // problem here is that Value has no notion of bitfields and thus the
 160           // Value's DataExtractor is sized like the bitfields CompilerType; a
 161           // sequence of bitfields, however, can be larger than their underlying
 162           // type.
 163           if (m_bitfield_bit_offset) {
 164             const bool thread_and_frame_only_if_stopped = true;
 165             ExecutionContext exe_ctx(GetExecutionContextRef().Lock(
 166                 thread_and_frame_only_if_stopped));
 167             if (auto type_bit_size = GetCompilerType().GetBitSize(
 168                     exe_ctx.GetBestExecutionContextScope())) {
 169               uint64_t bitfield_end =
 170                   m_bitfield_bit_size + m_bitfield_bit_offset;
 171               if (bitfield_end > *type_bit_size) {
 172                 uint64_t overhang_bytes =
 173                     (bitfield_end - *type_bit_size + 7) / 8;
 174                 m_byte_offset += overhang_bytes;
 175                 m_bitfield_bit_offset -= overhang_bytes * 8;
 176               }
 177             }
 178           }
 179
 180           // Set this object's scalar value to the address of its value by
 181           // adding its byte offset to the parent address
 182           m_value.GetScalar() += m_byte_offset;
 183         }
 184       } break;
 185
 186       case Value::ValueType::Scalar:
 187         // try to extract the child value from the parent's scalar value
 188         {
 189           Scalar scalar(m_value.GetScalar());
 190           scalar.ExtractBitfield(8 * m_byte_size, 8 * m_byte_offset);
 191           m_value.GetScalar() = scalar;
 192         }
 193         break;
 194       }
 195
 196       if (m_error.Success()) {
 197         const bool thread_and_frame_only_if_stopped = true;
 198         ExecutionContext exe_ctx(
 199             GetExecutionContextRef().Lock(thread_and_frame_only_if_stopped));
 200         if (GetCompilerType().GetTypeInfo() & lldb::eTypeHasValue) {
 201           Value &value = is_instance_ptr_base ? m_parent->GetValue() : m_value;
 202           m_error = value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
 203         } else {
 204           m_error.Clear(); // No value so nothing to read...
 205         }
 206       }
 207
 208     } else {
 209       m_error = Status::FromErrorStringWithFormat(
 210           "parent failed to evaluate: %s", parent->GetError().AsCString());
 211     }
 212   } else {
 213     m_error = Status::FromErrorString(
 214         "ValueObjectChild has a NULL parent ValueObject.");
 215   }
 216
 217   return m_error.Success();
 218 }
 219
 220 bool ValueObjectChild::IsInScope() {
 221   ValueObject *root(GetRoot());
 222   if (root)
 223     return root->IsInScope();
 224   return false;
 225 }