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

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