ClangExpressionVariable.h revision 360784 
1//===-- ClangExpressionVariable.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 liblldb_ClangExpressionVariable_h_
10#define liblldb_ClangExpressionVariable_h_
11
12#include <signal.h>
13#include <stdint.h>
14#include <string.h>
15
16#include <map>
17#include <string>
18#include <vector>
19
20#include "llvm/Support/Casting.h"
21
22#include "lldb/Core/ClangForward.h"
23#include "lldb/Core/Value.h"
24#include "lldb/Expression/ExpressionVariable.h"
25#include "lldb/Symbol/TaggedASTType.h"
26#include "lldb/Utility/ConstString.h"
27#include "lldb/lldb-public.h"
28
29namespace llvm {
30class Value;
31}
32
33namespace lldb_private {
34
35class ValueObjectConstResult;
36
37/// \class ClangExpressionVariable ClangExpressionVariable.h
38/// "lldb/Expression/ClangExpressionVariable.h" Encapsulates one variable for
39/// the expression parser.
40///
41/// The expression parser uses variables in three different contexts:
42///
43/// First, it stores persistent variables along with the process for use in
44/// expressions.  These persistent variables contain their own data and are
45/// typed.
46///
47/// Second, in an interpreted expression, it stores the local variables for
48/// the expression along with the expression.  These variables contain their
49/// own data and are typed.
50///
51/// Third, in a JIT-compiled expression, it stores the variables that the
52/// expression needs to have materialized and dematerialized at each
53/// execution.  These do not contain their own data but are named and typed.
54///
55/// This class supports all of these use cases using simple type polymorphism,
56/// and provides necessary support methods.  Its interface is RTTI-neutral.
57class ClangExpressionVariable : public ExpressionVariable {
58public:
59  ClangExpressionVariable(ExecutionContextScope *exe_scope,
60                          lldb::ByteOrder byte_order, uint32_t addr_byte_size);
61
62  ClangExpressionVariable(ExecutionContextScope *exe_scope, Value &value,
63                          ConstString name, uint16_t flags = EVNone);
64
65  ClangExpressionVariable(const lldb::ValueObjectSP &valobj_sp);
66
67  ClangExpressionVariable(ExecutionContextScope *exe_scope,
68                          ConstString name,
69                          const TypeFromUser &user_type,
70                          lldb::ByteOrder byte_order, uint32_t addr_byte_size);
71
72  /// Utility functions for dealing with ExpressionVariableLists in Clang-
73  /// specific ways
74
75  /// Finds a variable by NamedDecl in the list.
76  ///
77  /// \return
78  ///     The variable requested, or NULL if that variable is not in the list.
79  static ClangExpressionVariable *
80  FindVariableInList(ExpressionVariableList &list, const clang::NamedDecl *decl,
81                     uint64_t parser_id) {
82    lldb::ExpressionVariableSP var_sp;
83    for (size_t index = 0, size = list.GetSize(); index < size; ++index) {
84      var_sp = list.GetVariableAtIndex(index);
85
86      if (ClangExpressionVariable *clang_var =
87              llvm::dyn_cast<ClangExpressionVariable>(var_sp.get())) {
88        ClangExpressionVariable::ParserVars *parser_vars =
89            clang_var->GetParserVars(parser_id);
90
91        if (parser_vars && parser_vars->m_named_decl == decl)
92          return clang_var;
93      }
94    }
95    return nullptr;
96  }
97
98  /// If the variable contains its own data, make a Value point at it. If \a
99  /// exe_ctx in not NULL, the value will be resolved in with that execution
100  /// context.
101  ///
102  /// \param[in] value
103  ///     The value to point at the data.
104  ///
105  /// \param[in] exe_ctx
106  ///     The execution context to use to resolve \a value.
107  ///
108  /// \return
109  ///     True on success; false otherwise (in particular, if this variable
110  ///     does not contain its own data).
111  bool PointValueAtData(Value &value, ExecutionContext *exe_ctx);
112
113  /// The following values should not live beyond parsing
114  class ParserVars {
115  public:
116    ParserVars()
117        : m_parser_type(), m_named_decl(nullptr), m_llvm_value(nullptr),
118          m_lldb_value(), m_lldb_var(), m_lldb_sym(nullptr) {}
119
120    TypeFromParser
121        m_parser_type; ///< The type of the variable according to the parser
122    const clang::NamedDecl
123        *m_named_decl;         ///< The Decl corresponding to this variable
124    llvm::Value *m_llvm_value; ///< The IR value corresponding to this variable;
125                               ///usually a GlobalValue
126    lldb_private::Value
127        m_lldb_value;            ///< The value found in LLDB for this variable
128    lldb::VariableSP m_lldb_var; ///< The original variable for this variable
129    const lldb_private::Symbol *m_lldb_sym; ///< The original symbol for this
130                                            ///variable, if it was a symbol
131  };
132
133private:
134  typedef std::map<uint64_t, ParserVars> ParserVarMap;
135  ParserVarMap m_parser_vars;
136
137public:
138  /// Make this variable usable by the parser by allocating space for parser-
139  /// specific variables
140  void EnableParserVars(uint64_t parser_id) {
141    m_parser_vars.insert(std::make_pair(parser_id, ParserVars()));
142  }
143
144  /// Deallocate parser-specific variables
145  void DisableParserVars(uint64_t parser_id) { m_parser_vars.erase(parser_id); }
146
147  /// Access parser-specific variables
148  ParserVars *GetParserVars(uint64_t parser_id) {
149    ParserVarMap::iterator i = m_parser_vars.find(parser_id);
150
151    if (i == m_parser_vars.end())
152      return nullptr;
153    else
154      return &i->second;
155  }
156
157  /// The following values are valid if the variable is used by JIT code
158  struct JITVars {
159    JITVars() : m_alignment(0), m_size(0), m_offset(0) {}
160
161    lldb::offset_t
162        m_alignment; ///< The required alignment of the variable, in bytes
163    size_t m_size;   ///< The space required for the variable, in bytes
164    lldb::offset_t
165        m_offset; ///< The offset of the variable in the struct, in bytes
166  };
167
168private:
169  typedef std::map<uint64_t, JITVars> JITVarMap;
170  JITVarMap m_jit_vars;
171
172public:
173  /// Make this variable usable for materializing for the JIT by allocating
174  /// space for JIT-specific variables
175  void EnableJITVars(uint64_t parser_id) {
176    m_jit_vars.insert(std::make_pair(parser_id, JITVars()));
177  }
178
179  /// Deallocate JIT-specific variables
180  void DisableJITVars(uint64_t parser_id) { m_jit_vars.erase(parser_id); }
181
182  JITVars *GetJITVars(uint64_t parser_id) {
183    JITVarMap::iterator i = m_jit_vars.find(parser_id);
184
185    if (i == m_jit_vars.end())
186      return nullptr;
187    else
188      return &i->second;
189  }
190
191  TypeFromUser GetTypeFromUser();
192
193  // llvm casting support
194  static bool classof(const ExpressionVariable *ev) {
195    return ev->getKind() == ExpressionVariable::eKindClang;
196  }
197
198  /// Members
199  DISALLOW_COPY_AND_ASSIGN(ClangExpressionVariable);
200};
201
202} // namespace lldb_private
203
204#endif // liblldb_ClangExpressionVariable_h_
205