1 //===-- ExpressionVariable.h ------------------------------------*- C++ -*-===//
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 #ifndef LLDB_EXPRESSION_EXPRESSIONVARIABLE_H
10 #define LLDB_EXPRESSION_EXPRESSIONVARIABLE_H
11 
12 #include <memory>
13 #include <optional>
14 #include <vector>
15 
16 #include "llvm/ADT/DenseMap.h"
17 
18 #include "lldb/Core/ValueObject.h"
19 #include "lldb/Utility/ConstString.h"
20 #include "lldb/lldb-public.h"
21 #include "llvm/Support/ExtensibleRTTI.h"
22 
23 namespace lldb_private {
24 
25 class ExpressionVariable
26     : public std::enable_shared_from_this<ExpressionVariable>,
27       public llvm::RTTIExtends<ExpressionVariable, llvm::RTTIRoot> {
28 public:
29   /// LLVM RTTI support
30   static char ID;
31 
32   ExpressionVariable();
33 
34   virtual ~ExpressionVariable() = default;
35 
36   std::optional<uint64_t> GetByteSize() { return m_frozen_sp->GetByteSize(); }
37 
38   ConstString GetName() { return m_frozen_sp->GetName(); }
39 
40   lldb::ValueObjectSP GetValueObject() { return m_frozen_sp; }
41 
42   uint8_t *GetValueBytes();
43 
44   void ValueUpdated() { m_frozen_sp->ValueUpdated(); }
45 
46   RegisterInfo *GetRegisterInfo() {
47     return m_frozen_sp->GetValue().GetRegisterInfo();
48   }
49 
50   void SetRegisterInfo(const RegisterInfo *reg_info) {
51     return m_frozen_sp->GetValue().SetContext(
52         Value::ContextType::RegisterInfo, const_cast<RegisterInfo *>(reg_info));
53   }
54 
55   CompilerType GetCompilerType() { return m_frozen_sp->GetCompilerType(); }
56 
57   void SetCompilerType(const CompilerType &compiler_type) {
58     m_frozen_sp->GetValue().SetCompilerType(compiler_type);
59   }
60 
61   void SetName(ConstString name) { m_frozen_sp->SetName(name); }
62 
63   // this function is used to copy the address-of m_live_sp into m_frozen_sp
64   // this is necessary because the results of certain cast and pointer-
65   // arithmetic operations (such as those described in bugzilla issues 11588
66   // and 11618) generate frozen objects that do not have a valid address-of,
67   // which can be troublesome when using synthetic children providers.
68   // Transferring the address-of the live object solves these issues and
69   // provides the expected user-level behavior
70   void TransferAddress(bool force = false) {
71     if (m_live_sp.get() == nullptr)
72       return;
73 
74     if (m_frozen_sp.get() == nullptr)
75       return;
76 
77     if (force || (m_frozen_sp->GetLiveAddress() == LLDB_INVALID_ADDRESS))
78       m_frozen_sp->SetLiveAddress(m_live_sp->GetLiveAddress());
79   }
80 
81   enum Flags {
82     EVNone = 0,
83     EVIsLLDBAllocated = 1 << 0, ///< This variable is resident in a location
84                                 ///specifically allocated for it by LLDB in the
85                                 ///target process
86     EVIsProgramReference = 1 << 1, ///< This variable is a reference to a
87                                    ///(possibly invalid) area managed by the
88                                    ///target program
89     EVNeedsAllocation = 1 << 2,    ///< Space for this variable has yet to be
90                                    ///allocated in the target process
91     EVIsFreezeDried = 1 << 3, ///< This variable's authoritative version is in
92                               ///m_frozen_sp (for example, for
93                               ///statically-computed results)
94     EVNeedsFreezeDry =
95         1 << 4, ///< Copy from m_live_sp to m_frozen_sp during dematerialization
96     EVKeepInTarget = 1 << 5, ///< Keep the allocation after the expression is
97                              ///complete rather than freeze drying its contents
98                              ///and freeing it
99     EVTypeIsReference = 1 << 6, ///< The original type of this variable is a
100                                 ///reference, so materialize the value rather
101                                 ///than the location
102     EVBareRegister = 1 << 7 ///< This variable is a direct reference to $pc or
103                             ///some other entity.
104   };
105 
106   typedef uint16_t FlagType;
107 
108   FlagType m_flags; // takes elements of Flags
109 
110   // these should be private
111   lldb::ValueObjectSP m_frozen_sp;
112   lldb::ValueObjectSP m_live_sp;
113 };
114 
115 /// \class ExpressionVariableList ExpressionVariable.h
116 /// "lldb/Expression/ExpressionVariable.h"
117 /// A list of variable references.
118 ///
119 /// This class stores variables internally, acting as the permanent store.
120 class ExpressionVariableList {
121 public:
122   /// Implementation of methods in ExpressionVariableListBase
123   size_t GetSize() { return m_variables.size(); }
124 
125   lldb::ExpressionVariableSP GetVariableAtIndex(size_t index) {
126     lldb::ExpressionVariableSP var_sp;
127     if (index < m_variables.size())
128       var_sp = m_variables[index];
129     return var_sp;
130   }
131 
132   size_t AddVariable(const lldb::ExpressionVariableSP &var_sp) {
133     m_variables.push_back(var_sp);
134     return m_variables.size() - 1;
135   }
136 
137   lldb::ExpressionVariableSP
138   AddNewlyConstructedVariable(ExpressionVariable *var) {
139     lldb::ExpressionVariableSP var_sp(var);
140     m_variables.push_back(var_sp);
141     return m_variables.back();
142   }
143 
144   bool ContainsVariable(const lldb::ExpressionVariableSP &var_sp) {
145     const size_t size = m_variables.size();
146     for (size_t index = 0; index < size; ++index) {
147       if (m_variables[index].get() == var_sp.get())
148         return true;
149     }
150     return false;
151   }
152 
153   /// Finds a variable by name in the list.
154   ///
155   /// \param[in] name
156   ///     The name of the requested variable.
157   ///
158   /// \return
159   ///     The variable requested, or nullptr if that variable is not in the
160   ///     list.
161   lldb::ExpressionVariableSP GetVariable(ConstString name) {
162     lldb::ExpressionVariableSP var_sp;
163     for (size_t index = 0, size = GetSize(); index < size; ++index) {
164       var_sp = GetVariableAtIndex(index);
165       if (var_sp->GetName() == name)
166         return var_sp;
167     }
168     var_sp.reset();
169     return var_sp;
170   }
171 
172   lldb::ExpressionVariableSP GetVariable(llvm::StringRef name) {
173     if (name.empty())
174       return nullptr;
175 
176     for (size_t index = 0, size = GetSize(); index < size; ++index) {
177       auto var_sp = GetVariableAtIndex(index);
178       llvm::StringRef var_name_str = var_sp->GetName().GetStringRef();
179       if (var_name_str == name)
180         return var_sp;
181     }
182     return nullptr;
183   }
184 
185   void RemoveVariable(lldb::ExpressionVariableSP var_sp) {
186     for (std::vector<lldb::ExpressionVariableSP>::iterator
187              vi = m_variables.begin(),
188              ve = m_variables.end();
189          vi != ve; ++vi) {
190       if (vi->get() == var_sp.get()) {
191         m_variables.erase(vi);
192         return;
193       }
194     }
195   }
196 
197   void Clear() { m_variables.clear(); }
198 
199 private:
200   std::vector<lldb::ExpressionVariableSP> m_variables;
201 };
202 
203 class PersistentExpressionState
204     : public ExpressionVariableList,
205       public llvm::RTTIExtends<PersistentExpressionState, llvm::RTTIRoot> {
206 public:
207   /// LLVM RTTI support
208   static char ID;
209 
210   PersistentExpressionState();
211 
212   virtual ~PersistentExpressionState();
213 
214   virtual lldb::ExpressionVariableSP
215   CreatePersistentVariable(const lldb::ValueObjectSP &valobj_sp) = 0;
216 
217   virtual lldb::ExpressionVariableSP
218   CreatePersistentVariable(ExecutionContextScope *exe_scope,
219                            ConstString name, const CompilerType &type,
220                            lldb::ByteOrder byte_order,
221                            uint32_t addr_byte_size) = 0;
222 
223   /// Return a new persistent variable name with the specified prefix.
224   virtual ConstString GetNextPersistentVariableName(bool is_error = false) = 0;
225 
226   virtual void
227   RemovePersistentVariable(lldb::ExpressionVariableSP variable) = 0;
228 
229   virtual std::optional<CompilerType>
230   GetCompilerTypeFromPersistentDecl(ConstString type_name) = 0;
231 
232   virtual lldb::addr_t LookupSymbol(ConstString name);
233 
234   void RegisterExecutionUnit(lldb::IRExecutionUnitSP &execution_unit_sp);
235 
236 protected:
237   virtual llvm::StringRef
238   GetPersistentVariablePrefix(bool is_error = false) const = 0;
239 
240 private:
241   typedef std::set<lldb::IRExecutionUnitSP> ExecutionUnitSet;
242   ExecutionUnitSet
243       m_execution_units; ///< The execution units that contain valuable symbols.
244 
245   typedef llvm::DenseMap<const char *, lldb::addr_t> SymbolMap;
246   SymbolMap
247       m_symbol_map; ///< The addresses of the symbols in m_execution_units.
248 };
249 
250 } // namespace lldb_private
251 
252 #endif // LLDB_EXPRESSION_EXPRESSIONVARIABLE_H
253