lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.h

   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
  28 namespace llvm {
  29 class Value;
  30 }
  31
  32 namespace clang {
  33 class NamedDecl;
  34 }
  35
  36 namespace lldb_private {
  37
  38 class 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.
  60 class ClangExpressionVariable
  61     : public llvm::RTTIExtends<ClangExpressionVariable, ExpressionVariable> {
  62 public:
  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
 144 private:
 145   typedef std::map<uint64_t, ParserVars> ParserVarMap;
 146   ParserVarMap m_parser_vars;
 147
 148 public:
 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
 179 private:
 180   typedef std::map<uint64_t, JITVars> JITVarMap;
 181   JITVarMap m_jit_vars;
 182
 183 public:
 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