1 //===-- ClangExpressionVariable.h -------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef liblldb_ClangExpressionVariable_h_
11 #define liblldb_ClangExpressionVariable_h_
12 
13 // C Includes
14 #include <signal.h>
15 #include <stdint.h>
16 #include <string.h>
17 
18 // C++ Includes
19 #include <map>
20 #include <string>
21 #include <vector>
22 
23 // Other libraries and framework includes
24 #include "llvm/Support/Casting.h"
25 
26 // Project includes
27 #include "lldb/Core/ClangForward.h"
28 #include "lldb/Core/ConstString.h"
29 #include "lldb/Core/Value.h"
30 #include "lldb/Expression/ExpressionVariable.h"
31 #include "lldb/Symbol/TaggedASTType.h"
32 #include "lldb/lldb-public.h"
33 
34 namespace llvm {
35 class Value;
36 }
37 
38 namespace lldb_private {
39 
40 class ValueObjectConstResult;
41 
42 //----------------------------------------------------------------------
43 /// @class ClangExpressionVariable ClangExpressionVariable.h
44 /// "lldb/Expression/ClangExpressionVariable.h"
45 /// @brief Encapsulates one variable for the expression parser.
46 ///
47 /// The expression parser uses variables in three different contexts:
48 ///
49 /// First, it stores persistent variables along with the process for use
50 /// in expressions.  These persistent variables contain their own data
51 /// and are typed.
52 ///
53 /// Second, in an interpreted expression, it stores the local variables
54 /// for the expression along with the expression.  These variables
55 /// contain their own data and are typed.
56 ///
57 /// Third, in a JIT-compiled expression, it stores the variables that
58 /// the expression needs to have materialized and dematerialized at each
59 /// execution.  These do not contain their own data but are named and
60 /// typed.
61 ///
62 /// This class supports all of these use cases using simple type
63 /// polymorphism, and provides necessary support methods.  Its interface
64 /// is RTTI-neutral.
65 //----------------------------------------------------------------------
66 class ClangExpressionVariable : public ExpressionVariable {
67 public:
68   ClangExpressionVariable(ExecutionContextScope *exe_scope,
69                           lldb::ByteOrder byte_order, uint32_t addr_byte_size);
70 
71   ClangExpressionVariable(ExecutionContextScope *exe_scope, Value &value,
72                           const ConstString &name, uint16_t flags = EVNone);
73 
74   ClangExpressionVariable(const lldb::ValueObjectSP &valobj_sp);
75 
76   ClangExpressionVariable(ExecutionContextScope *exe_scope,
77                           const ConstString &name,
78                           const TypeFromUser &user_type,
79                           lldb::ByteOrder byte_order, uint32_t addr_byte_size);
80 
81   //----------------------------------------------------------------------
82   /// Utility functions for dealing with ExpressionVariableLists in
83   /// Clang-specific ways
84   //----------------------------------------------------------------------
85 
86   //----------------------------------------------------------------------
87   /// Finds a variable by NamedDecl in the list.
88   ///
89   /// @param[in] name
90   ///     The name of the requested variable.
91   ///
92   /// @return
93   ///     The variable requested, or NULL if that variable is not in the list.
94   //----------------------------------------------------------------------
95   static ClangExpressionVariable *
96   FindVariableInList(ExpressionVariableList &list, const clang::NamedDecl *decl,
97                      uint64_t parser_id) {
98     lldb::ExpressionVariableSP var_sp;
99     for (size_t index = 0, size = list.GetSize(); index < size; ++index) {
100       var_sp = list.GetVariableAtIndex(index);
101 
102       if (ClangExpressionVariable *clang_var =
103               llvm::dyn_cast<ClangExpressionVariable>(var_sp.get())) {
104         ClangExpressionVariable::ParserVars *parser_vars =
105             clang_var->GetParserVars(parser_id);
106 
107         if (parser_vars && parser_vars->m_named_decl == decl)
108           return clang_var;
109       }
110     }
111     return nullptr;
112   }
113 
114   //----------------------------------------------------------------------
115   /// If the variable contains its own data, make a Value point at it.
116   /// If \a exe_ctx in not NULL, the value will be resolved in with
117   /// that execution context.
118   ///
119   /// @param[in] value
120   ///     The value to point at the data.
121   ///
122   /// @param[in] exe_ctx
123   ///     The execution context to use to resolve \a value.
124   ///
125   /// @return
126   ///     True on success; false otherwise (in particular, if this variable
127   ///     does not contain its own data).
128   //----------------------------------------------------------------------
129   bool PointValueAtData(Value &value, ExecutionContext *exe_ctx);
130 
131   //----------------------------------------------------------------------
132   /// The following values should not live beyond parsing
133   //----------------------------------------------------------------------
134   class ParserVars {
135   public:
136     ParserVars()
137         : m_parser_type(), m_named_decl(NULL), m_llvm_value(NULL),
138           m_lldb_value(), m_lldb_var(), m_lldb_sym(NULL) {}
139 
140     TypeFromParser
141         m_parser_type; ///< The type of the variable according to the parser
142     const clang::NamedDecl
143         *m_named_decl;         ///< The Decl corresponding to this variable
144     llvm::Value *m_llvm_value; ///< The IR value corresponding to this variable;
145                                ///usually a GlobalValue
146     lldb_private::Value
147         m_lldb_value;            ///< The value found in LLDB for this variable
148     lldb::VariableSP m_lldb_var; ///< The original variable for this variable
149     const lldb_private::Symbol *m_lldb_sym; ///< The original symbol for this
150                                             ///variable, if it was a symbol
151   };
152 
153 private:
154   typedef std::map<uint64_t, ParserVars> ParserVarMap;
155   ParserVarMap m_parser_vars;
156 
157 public:
158   //----------------------------------------------------------------------
159   /// Make this variable usable by the parser by allocating space for
160   /// parser-specific variables
161   //----------------------------------------------------------------------
162   void EnableParserVars(uint64_t parser_id) {
163     m_parser_vars.insert(std::make_pair(parser_id, ParserVars()));
164   }
165 
166   //----------------------------------------------------------------------
167   /// Deallocate parser-specific variables
168   //----------------------------------------------------------------------
169   void DisableParserVars(uint64_t parser_id) { m_parser_vars.erase(parser_id); }
170 
171   //----------------------------------------------------------------------
172   /// Access parser-specific variables
173   //----------------------------------------------------------------------
174   ParserVars *GetParserVars(uint64_t parser_id) {
175     ParserVarMap::iterator i = m_parser_vars.find(parser_id);
176 
177     if (i == m_parser_vars.end())
178       return NULL;
179     else
180       return &i->second;
181   }
182 
183   //----------------------------------------------------------------------
184   /// The following values are valid if the variable is used by JIT code
185   //----------------------------------------------------------------------
186   struct JITVars {
187     JITVars() : m_alignment(0), m_size(0), m_offset(0) {}
188 
189     lldb::offset_t
190         m_alignment; ///< The required alignment of the variable, in bytes
191     size_t m_size;   ///< The space required for the variable, in bytes
192     lldb::offset_t
193         m_offset; ///< The offset of the variable in the struct, in bytes
194   };
195 
196 private:
197   typedef std::map<uint64_t, JITVars> JITVarMap;
198   JITVarMap m_jit_vars;
199 
200 public:
201   //----------------------------------------------------------------------
202   /// Make this variable usable for materializing for the JIT by allocating
203   /// space for JIT-specific variables
204   //----------------------------------------------------------------------
205   void EnableJITVars(uint64_t parser_id) {
206     m_jit_vars.insert(std::make_pair(parser_id, JITVars()));
207   }
208 
209   //----------------------------------------------------------------------
210   /// Deallocate JIT-specific variables
211   //----------------------------------------------------------------------
212   void DisableJITVars(uint64_t parser_id) { m_jit_vars.erase(parser_id); }
213 
214   JITVars *GetJITVars(uint64_t parser_id) {
215     JITVarMap::iterator i = m_jit_vars.find(parser_id);
216 
217     if (i == m_jit_vars.end())
218       return NULL;
219     else
220       return &i->second;
221   }
222 
223   TypeFromUser GetTypeFromUser();
224 
225   //------------------------------------------------------------------
226   // llvm casting support
227   //------------------------------------------------------------------
228   static bool classof(const ExpressionVariable *ev) {
229     return ev->getKind() == ExpressionVariable::eKindClang;
230   }
231 
232   //----------------------------------------------------------------------
233   /// Members
234   //----------------------------------------------------------------------
235   DISALLOW_COPY_AND_ASSIGN(ClangExpressionVariable);
236 };
237 
238 } // namespace lldb_private
239 
240 #endif // liblldb_ClangExpressionVariable_h_
241