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
27using namespace lldb_private;
28
29ValueObjectChild::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
45ValueObjectChild::~ValueObjectChild() = default;
46
47lldb::ValueType ValueObjectChild::GetValueType() const {
48 return m_parent->GetValueType();
49}
50
51llvm::Expected<uint32_t> ValueObjectChild::CalculateNumChildren(uint32_t max) {
52 ExecutionContext exe_ctx(GetExecutionContextRef());
53 auto children_count = GetCompilerType().GetNumChildren(omit_empty_base_classes: true, exe_ctx: &exe_ctx);
54 if (!children_count)
55 return children_count;
56 return *children_count <= max ? *children_count : max;
57}
58
59static void AdjustForBitfieldness(ConstString &name,
60 uint8_t bitfield_bit_size) {
61 if (name && bitfield_bit_size)
62 name.SetString(llvm::formatv(Fmt: "{0}:{1}", Vals&: name, Vals&: bitfield_bit_size).str());
63}
64
65ConstString ValueObjectChild::GetTypeName() {
66 if (m_type_name.IsEmpty()) {
67 m_type_name = GetCompilerType().GetTypeName();
68 AdjustForBitfieldness(name&: m_type_name, bitfield_bit_size: m_bitfield_bit_size);
69 }
70 return m_type_name;
71}
72
73ConstString ValueObjectChild::GetQualifiedTypeName() {
74 ConstString qualified_name = GetCompilerType().GetTypeName();
75 AdjustForBitfieldness(name&: qualified_name, bitfield_bit_size: m_bitfield_bit_size);
76 return qualified_name;
77}
78
79ConstString ValueObjectChild::GetDisplayTypeName() {
80 ConstString display_name = GetCompilerType().GetDisplayTypeName();
81 AdjustForBitfieldness(name&: display_name, bitfield_bit_size: m_bitfield_bit_size);
82 return display_name;
83}
84
85LazyBool 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
102bool ValueObjectChild::UpdateValue() {
103 m_error.Clear();
104 SetValueIsValid(false);
105 ValueObject *parent = m_parent;
106 if (parent) {
107 if (parent->UpdateValueIfNeeded(update_format: 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(mask: lldb::eTypeInstanceIsPointer)));
119
120 if (parent->GetCompilerType().ShouldTreatScalarValueAsAddress()) {
121 m_value.GetScalar() = parent->GetPointerValue().address;
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(str: "parent address is invalid.");
154 } else if (addr == 0) {
155 m_error = Status::FromErrorString(str: "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 =
168 llvm::expectedToOptional(E: 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 = value.GetValueAsData(exe_ctx: &exe_ctx, data&: m_data, module: GetModule().get());
204 } else {
205 m_error.Clear(); // No value so nothing to read...
206 }
207 }
208
209 } else {
210 m_error = Status::FromErrorStringWithFormat(
211 format: "parent failed to evaluate: %s", parent->GetError().AsCString());
212 }
213 } else {
214 m_error = Status::FromErrorString(
215 str: "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/ValueObject/ValueObjectChild.cpp