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