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/Core/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
27using namespace lldb_private;
28
29ValueObjectChild::ValueObjectChild(
30 ValueObject &parent, const CompilerType &compiler_type,
31 ConstString name, uint64_t byte_size, int32_t byte_offset,
32 uint32_t bitfield_bit_size, uint32_t bitfield_bit_offset,
33 bool is_base_class, bool is_deref_of_parent,
34 AddressType child_ptr_or_ref_addr_type, uint64_t language_flags)
35 : ValueObject(parent), m_compiler_type(compiler_type),
36 m_byte_size(byte_size), m_byte_offset(byte_offset),
37 m_bitfield_bit_size(bitfield_bit_size),
38 m_bitfield_bit_offset(bitfield_bit_offset),
39 m_is_base_class(is_base_class), m_is_deref_of_parent(is_deref_of_parent),
40 m_can_update_with_invalid_exe_ctx() {
41 m_name = name;
42 SetAddressTypeOfChildren(child_ptr_or_ref_addr_type);
43 SetLanguageFlags(language_flags);
44}
45
46ValueObjectChild::~ValueObjectChild() = default;
47
48lldb::ValueType ValueObjectChild::GetValueType() const {
49 return m_parent->GetValueType();
50}
51
52llvm::Expected<uint32_t> ValueObjectChild::CalculateNumChildren(uint32_t max) {
53 ExecutionContext exe_ctx(GetExecutionContextRef());
54 auto children_count = GetCompilerType().GetNumChildren(omit_empty_base_classes: true, exe_ctx: &exe_ctx);
55 if (!children_count)
56 return children_count;
57 return *children_count <= max ? *children_count : max;
58}
59
60static void AdjustForBitfieldness(ConstString &name,
61 uint8_t bitfield_bit_size) {
62 if (name && bitfield_bit_size)
63 name.SetString(llvm::formatv(Fmt: "{0}:{1}", Vals&: name, Vals&: bitfield_bit_size).str());
64}
65
66ConstString ValueObjectChild::GetTypeName() {
67 if (m_type_name.IsEmpty()) {
68 m_type_name = GetCompilerType().GetTypeName();
69 AdjustForBitfieldness(name&: m_type_name, bitfield_bit_size: m_bitfield_bit_size);
70 }
71 return m_type_name;
72}
73
74ConstString ValueObjectChild::GetQualifiedTypeName() {
75 ConstString qualified_name = GetCompilerType().GetTypeName();
76 AdjustForBitfieldness(name&: qualified_name, bitfield_bit_size: m_bitfield_bit_size);
77 return qualified_name;
78}
79
80ConstString ValueObjectChild::GetDisplayTypeName() {
81 ConstString display_name = GetCompilerType().GetDisplayTypeName();
82 AdjustForBitfieldness(name&: display_name, bitfield_bit_size: m_bitfield_bit_size);
83 return display_name;
84}
85
86LazyBool ValueObjectChild::CanUpdateWithInvalidExecutionContext() {
87 if (m_can_update_with_invalid_exe_ctx)
88 return *m_can_update_with_invalid_exe_ctx;
89 if (m_parent) {
90 ValueObject *opinionated_parent =
91 m_parent->FollowParentChain([](ValueObject *valobj) -> bool {
92 return (valobj->CanUpdateWithInvalidExecutionContext() ==
93 eLazyBoolCalculate);
94 });
95 if (opinionated_parent)
96 return *(m_can_update_with_invalid_exe_ctx =
97 opinionated_parent->CanUpdateWithInvalidExecutionContext());
98 }
99 return *(m_can_update_with_invalid_exe_ctx =
100 this->ValueObject::CanUpdateWithInvalidExecutionContext());
101}
102
103bool ValueObjectChild::UpdateValue() {
104 m_error.Clear();
105 SetValueIsValid(false);
106 ValueObject *parent = m_parent;
107 if (parent) {
108 if (parent->UpdateValueIfNeeded(update_format: false)) {
109 m_value.SetCompilerType(GetCompilerType());
110
111 CompilerType parent_type(parent->GetCompilerType());
112 // Copy the parent scalar value and the scalar value type
113 m_value.GetScalar() = parent->GetValue().GetScalar();
114 m_value.SetValueType(parent->GetValue().GetValueType());
115
116 Flags parent_type_flags(parent_type.GetTypeInfo());
117 const bool is_instance_ptr_base =
118 ((m_is_base_class) &&
119 (parent_type_flags.AnySet(mask: lldb::eTypeInstanceIsPointer)));
120
121 if (parent->GetCompilerType().ShouldTreatScalarValueAsAddress()) {
122 m_value.GetScalar() = parent->GetPointerValue();
123
124 switch (parent->GetAddressTypeOfChildren()) {
125 case eAddressTypeFile: {
126 lldb::ProcessSP process_sp(GetProcessSP());
127 if (process_sp && process_sp->IsAlive())
128 m_value.SetValueType(Value::ValueType::LoadAddress);
129 else
130 m_value.SetValueType(Value::ValueType::FileAddress);
131 } break;
132 case eAddressTypeLoad:
133 m_value.SetValueType(is_instance_ptr_base
134 ? Value::ValueType::Scalar
135 : Value::ValueType::LoadAddress);
136 break;
137 case eAddressTypeHost:
138 m_value.SetValueType(Value::ValueType::HostAddress);
139 break;
140 case eAddressTypeInvalid:
141 // TODO: does this make sense?
142 m_value.SetValueType(Value::ValueType::Scalar);
143 break;
144 }
145 }
146 switch (m_value.GetValueType()) {
147 case Value::ValueType::Invalid:
148 break;
149 case Value::ValueType::LoadAddress:
150 case Value::ValueType::FileAddress:
151 case Value::ValueType::HostAddress: {
152 lldb::addr_t addr = m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
153 if (addr == LLDB_INVALID_ADDRESS) {
154 m_error.SetErrorString("parent address is invalid.");
155 } else if (addr == 0) {
156 m_error.SetErrorString("parent is NULL");
157 } else {
158 // If a bitfield doesn't fit into the child_byte_size'd window at
159 // child_byte_offset, move the window forward until it fits. The
160 // problem here is that Value has no notion of bitfields and thus the
161 // Value's DataExtractor is sized like the bitfields CompilerType; a
162 // sequence of bitfields, however, can be larger than their underlying
163 // type.
164 if (m_bitfield_bit_offset) {
165 const bool thread_and_frame_only_if_stopped = true;
166 ExecutionContext exe_ctx(GetExecutionContextRef().Lock(
167 thread_and_frame_only_if_stopped));
168 if (auto type_bit_size = GetCompilerType().GetBitSize(
169 exe_scope: exe_ctx.GetBestExecutionContextScope())) {
170 uint64_t bitfield_end =
171 m_bitfield_bit_size + m_bitfield_bit_offset;
172 if (bitfield_end > *type_bit_size) {
173 uint64_t overhang_bytes =
174 (bitfield_end - *type_bit_size + 7) / 8;
175 m_byte_offset += overhang_bytes;
176 m_bitfield_bit_offset -= overhang_bytes * 8;
177 }
178 }
179 }
180
181 // Set this object's scalar value to the address of its value by
182 // adding its byte offset to the parent address
183 m_value.GetScalar() += m_byte_offset;
184 }
185 } break;
186
187 case Value::ValueType::Scalar:
188 // try to extract the child value from the parent's scalar value
189 {
190 Scalar scalar(m_value.GetScalar());
191 scalar.ExtractBitfield(bit_size: 8 * m_byte_size, bit_offset: 8 * m_byte_offset);
192 m_value.GetScalar() = scalar;
193 }
194 break;
195 }
196
197 if (m_error.Success()) {
198 const bool thread_and_frame_only_if_stopped = true;
199 ExecutionContext exe_ctx(
200 GetExecutionContextRef().Lock(thread_and_frame_only_if_stopped));
201 if (GetCompilerType().GetTypeInfo() & lldb::eTypeHasValue) {
202 Value &value = is_instance_ptr_base ? m_parent->GetValue() : m_value;
203 m_error =
204 value.GetValueAsData(exe_ctx: &exe_ctx, data&: m_data, module: GetModule().get());
205 } else {
206 m_error.Clear(); // No value so nothing to read...
207 }
208 }
209
210 } else {
211 m_error.SetErrorStringWithFormat("parent failed to evaluate: %s",
212 parent->GetError().AsCString());
213 }
214 } else {
215 m_error.SetErrorString("ValueObjectChild has a NULL parent ValueObject.");
216 }
217
218 return m_error.Success();
219}
220
221bool ValueObjectChild::IsInScope() {
222 ValueObject *root(GetRoot());
223 if (root)
224 return root->IsInScope();
225 return false;
226}
227

source code of lldb/source/Core/ValueObjectChild.cpp