1 //===-- ValueObjectMemory.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/ValueObjectMemory.h"
10 #include "lldb/Core/Value.h"
11 #include "lldb/Core/ValueObject.h"
12 #include "lldb/Symbol/Type.h"
13 #include "lldb/Target/ExecutionContext.h"
14 #include "lldb/Target/Target.h"
15 #include "lldb/Utility/DataExtractor.h"
16 #include "lldb/Utility/Scalar.h"
17 #include "lldb/Utility/Status.h"
18 #include "lldb/lldb-types.h"
19 #include "llvm/Support/ErrorHandling.h"
20 
21 #include <cassert>
22 #include <memory>
23 #include <optional>
24 
25 namespace lldb_private {
26 class ExecutionContextScope;
27 }
28 
29 using namespace lldb;
30 using namespace lldb_private;
31 
32 ValueObjectSP ValueObjectMemory::Create(ExecutionContextScope *exe_scope,
33                                         llvm::StringRef name,
34                                         const Address &address,
35                                         lldb::TypeSP &type_sp) {
36   auto manager_sp = ValueObjectManager::Create();
37   return (new ValueObjectMemory(exe_scope, *manager_sp, name, address, type_sp))
38       ->GetSP();
39 }
40 
41 ValueObjectSP ValueObjectMemory::Create(ExecutionContextScope *exe_scope,
42                                         llvm::StringRef name,
43                                         const Address &address,
44                                         const CompilerType &ast_type) {
45   auto manager_sp = ValueObjectManager::Create();
46   return (new ValueObjectMemory(exe_scope, *manager_sp, name, address,
47                                 ast_type))
48       ->GetSP();
49 }
50 
51 ValueObjectMemory::ValueObjectMemory(ExecutionContextScope *exe_scope,
52                                      ValueObjectManager &manager,
53                                      llvm::StringRef name,
54                                      const Address &address,
55                                      lldb::TypeSP &type_sp)
56     : ValueObject(exe_scope, manager), m_address(address), m_type_sp(type_sp),
57       m_compiler_type() {
58   // Do not attempt to construct one of these objects with no variable!
59   assert(m_type_sp.get() != nullptr);
60   SetName(ConstString(name));
61   m_value.SetContext(Value::ContextType::LLDBType, m_type_sp.get());
62   TargetSP target_sp(GetTargetSP());
63   lldb::addr_t load_address = m_address.GetLoadAddress(target_sp.get());
64   if (load_address != LLDB_INVALID_ADDRESS) {
65     m_value.SetValueType(Value::ValueType::LoadAddress);
66     m_value.GetScalar() = load_address;
67   } else {
68     lldb::addr_t file_address = m_address.GetFileAddress();
69     if (file_address != LLDB_INVALID_ADDRESS) {
70       m_value.SetValueType(Value::ValueType::FileAddress);
71       m_value.GetScalar() = file_address;
72     } else {
73       m_value.GetScalar() = m_address.GetOffset();
74       m_value.SetValueType(Value::ValueType::Scalar);
75     }
76   }
77 }
78 
79 ValueObjectMemory::ValueObjectMemory(ExecutionContextScope *exe_scope,
80                                      ValueObjectManager &manager,
81                                      llvm::StringRef name,
82                                      const Address &address,
83                                      const CompilerType &ast_type)
84     : ValueObject(exe_scope, manager), m_address(address), m_type_sp(),
85       m_compiler_type(ast_type) {
86   // Do not attempt to construct one of these objects with no variable!
87   assert(m_compiler_type.IsValid());
88 
89   TargetSP target_sp(GetTargetSP());
90 
91   SetName(ConstString(name));
92   m_value.SetCompilerType(m_compiler_type);
93   lldb::addr_t load_address = m_address.GetLoadAddress(target_sp.get());
94   if (load_address != LLDB_INVALID_ADDRESS) {
95     m_value.SetValueType(Value::ValueType::LoadAddress);
96     m_value.GetScalar() = load_address;
97   } else {
98     lldb::addr_t file_address = m_address.GetFileAddress();
99     if (file_address != LLDB_INVALID_ADDRESS) {
100       m_value.SetValueType(Value::ValueType::FileAddress);
101       m_value.GetScalar() = file_address;
102     } else {
103       m_value.GetScalar() = m_address.GetOffset();
104       m_value.SetValueType(Value::ValueType::Scalar);
105     }
106   }
107 }
108 
109 ValueObjectMemory::~ValueObjectMemory() = default;
110 
111 CompilerType ValueObjectMemory::GetCompilerTypeImpl() {
112   if (m_type_sp)
113     return m_type_sp->GetForwardCompilerType();
114   return m_compiler_type;
115 }
116 
117 ConstString ValueObjectMemory::GetTypeName() {
118   if (m_type_sp)
119     return m_type_sp->GetName();
120   return m_compiler_type.GetTypeName();
121 }
122 
123 ConstString ValueObjectMemory::GetDisplayTypeName() {
124   if (m_type_sp)
125     return m_type_sp->GetForwardCompilerType().GetDisplayTypeName();
126   return m_compiler_type.GetDisplayTypeName();
127 }
128 
129 size_t ValueObjectMemory::CalculateNumChildren(uint32_t max) {
130   if (m_type_sp) {
131     auto child_count = m_type_sp->GetNumChildren(true);
132     return child_count <= max ? child_count : max;
133   }
134 
135   ExecutionContext exe_ctx(GetExecutionContextRef());
136   const bool omit_empty_base_classes = true;
137   auto child_count =
138       m_compiler_type.GetNumChildren(omit_empty_base_classes, &exe_ctx);
139   return child_count <= max ? child_count : max;
140 }
141 
142 std::optional<uint64_t> ValueObjectMemory::GetByteSize() {
143   ExecutionContext exe_ctx(GetExecutionContextRef());
144   if (m_type_sp)
145     return m_type_sp->GetByteSize(exe_ctx.GetBestExecutionContextScope());
146   return m_compiler_type.GetByteSize(exe_ctx.GetBestExecutionContextScope());
147 }
148 
149 lldb::ValueType ValueObjectMemory::GetValueType() const {
150   // RETHINK: Should this be inherited from somewhere?
151   return lldb::eValueTypeVariableGlobal;
152 }
153 
154 bool ValueObjectMemory::UpdateValue() {
155   SetValueIsValid(false);
156   m_error.Clear();
157 
158   ExecutionContext exe_ctx(GetExecutionContextRef());
159 
160   Target *target = exe_ctx.GetTargetPtr();
161   if (target) {
162     m_data.SetByteOrder(target->GetArchitecture().GetByteOrder());
163     m_data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
164   }
165 
166   Value old_value(m_value);
167   if (m_address.IsValid()) {
168     Value::ValueType value_type = m_value.GetValueType();
169 
170     switch (value_type) {
171     case Value::ValueType::Invalid:
172       m_error.SetErrorString("Invalid value");
173       return false;
174     case Value::ValueType::Scalar:
175       // The variable value is in the Scalar value inside the m_value. We can
176       // point our m_data right to it.
177       m_error = m_value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
178       break;
179 
180     case Value::ValueType::FileAddress:
181     case Value::ValueType::LoadAddress:
182     case Value::ValueType::HostAddress:
183       // The DWARF expression result was an address in the inferior process. If
184       // this variable is an aggregate type, we just need the address as the
185       // main value as all child variable objects will rely upon this location
186       // and add an offset and then read their own values as needed. If this
187       // variable is a simple type, we read all data for it into m_data. Make
188       // sure this type has a value before we try and read it
189 
190       // If we have a file address, convert it to a load address if we can.
191       if (value_type == Value::ValueType::FileAddress &&
192           exe_ctx.GetProcessPtr()) {
193         lldb::addr_t load_addr = m_address.GetLoadAddress(target);
194         if (load_addr != LLDB_INVALID_ADDRESS) {
195           m_value.SetValueType(Value::ValueType::LoadAddress);
196           m_value.GetScalar() = load_addr;
197         }
198       }
199 
200       if (!CanProvideValue()) {
201         // this value object represents an aggregate type whose children have
202         // values, but this object does not. So we say we are changed if our
203         // location has changed.
204         SetValueDidChange(value_type != old_value.GetValueType() ||
205                           m_value.GetScalar() != old_value.GetScalar());
206       } else {
207         // Copy the Value and set the context to use our Variable so it can
208         // extract read its value into m_data appropriately
209         Value value(m_value);
210         if (m_type_sp)
211           value.SetContext(Value::ContextType::LLDBType, m_type_sp.get());
212         else {
213           value.SetCompilerType(m_compiler_type);
214         }
215 
216         m_error = value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
217       }
218       break;
219     }
220 
221     SetValueIsValid(m_error.Success());
222   }
223   return m_error.Success();
224 }
225 
226 bool ValueObjectMemory::IsInScope() {
227   // FIXME: Maybe try to read the memory address, and if that works, then
228   // we are in scope?
229   return true;
230 }
231 
232 lldb::ModuleSP ValueObjectMemory::GetModule() { return m_address.GetModule(); }
233