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      1 //===-- ClangExpressionParser.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_ClangExpressionParser_h_
     11 #define liblldb_ClangExpressionParser_h_
     12 
     13 #include "lldb/lldb-public.h"
     14 #include "lldb/Core/ArchSpec.h"
     15 #include "lldb/Core/ClangForward.h"
     16 #include "lldb/Core/Error.h"
     17 #include "lldb/Expression/IRForTarget.h"
     18 
     19 #include <string>
     20 #include <vector>
     21 
     22 namespace lldb_private
     23 {
     24 
     25 class IRExecutionUnit;
     26 
     27 //----------------------------------------------------------------------
     28 /// @class ClangExpressionParser ClangExpressionParser.h "lldb/Expression/ClangExpressionParser.h"
     29 /// @brief Encapsulates an instance of Clang that can parse expressions.
     30 ///
     31 /// ClangExpressionParser is responsible for preparing an instance of
     32 /// ClangExpression for execution.  ClangExpressionParser uses ClangExpression
     33 /// as a glorified parameter list, performing the required parsing and
     34 /// conversion to formats (DWARF bytecode, or JIT compiled machine code)
     35 /// that can be executed.
     36 //----------------------------------------------------------------------
     37 class ClangExpressionParser
     38 {
     39 public:
     40     //------------------------------------------------------------------
     41     /// Constructor
     42     ///
     43     /// Initializes class variabes.
     44     ///
     45     /// @param[in] exe_scope,
     46     ///     If non-NULL, an execution context scope that can help to
     47     ///     correctly create an expression with a valid process for
     48     ///     optional tuning Objective-C runtime support. Can be NULL.
     49     ///
     50     /// @param[in] expr
     51     ///     The expression to be parsed.
     52     //------------------------------------------------------------------
     53     ClangExpressionParser (ExecutionContextScope *exe_scope,
     54                            ClangExpression &expr);
     55 
     56     //------------------------------------------------------------------
     57     /// Destructor
     58     //------------------------------------------------------------------
     59     ~ClangExpressionParser ();
     60 
     61     //------------------------------------------------------------------
     62     /// Parse a single expression and convert it to IR using Clang.  Don't
     63     /// wrap the expression in anything at all.
     64     ///
     65     /// @param[in] stream
     66     ///     The stream to print errors to.
     67     ///
     68     /// @return
     69     ///     The number of errors encountered during parsing.  0 means
     70     ///     success.
     71     //------------------------------------------------------------------
     72     unsigned
     73     Parse (Stream &stream);
     74 
     75     //------------------------------------------------------------------
     76     /// Ready an already-parsed expression for execution, possibly
     77     /// evaluating it statically.
     78     ///
     79     /// @param[out] func_addr
     80     ///     The address to which the function has been written.
     81     ///
     82     /// @param[out] func_end
     83     ///     The end of the function's allocated memory region.  (func_addr
     84     ///     and func_end do not delimit an allocated region; the allocated
     85     ///     region may begin before func_addr.)
     86     ///
     87     /// @param[in] execution_unit_ap
     88     ///     After parsing, ownership of the execution unit for
     89     ///     for the expression is handed to this unique pointer.
     90     ///
     91     /// @param[in] exe_ctx
     92     ///     The execution context to write the function into.
     93     ///
     94     /// @param[out] evaluated_statically
     95     ///     Set to true if the expression could be interpreted statically;
     96     ///     untouched otherwise.
     97     ///
     98     /// @param[out] const_result
     99     ///     If the result of the expression is constant, and the
    100     ///     expression has no side effects, this is set to the result of the
    101     ///     expression.
    102     ///
    103     /// @param[in] execution_policy
    104     ///     Determines whether the expression must be JIT-compiled, must be
    105     ///     evaluated statically, or whether this decision may be made
    106     ///     opportunistically.
    107     ///
    108     /// @return
    109     ///     An error code indicating the success or failure of the operation.
    110     ///     Test with Success().
    111     //------------------------------------------------------------------
    112     Error
    113     PrepareForExecution (lldb::addr_t &func_addr,
    114                          lldb::addr_t &func_end,
    115                          std::unique_ptr<IRExecutionUnit> &execution_unit_ap,
    116                          ExecutionContext &exe_ctx,
    117                          bool &can_interpret,
    118                          lldb_private::ExecutionPolicy execution_policy);
    119 
    120     //------------------------------------------------------------------
    121     /// Disassemble the machine code for a JITted function from the target
    122     /// process's memory and print the result to a stream.
    123     ///
    124     /// @param[in] stream
    125     ///     The stream to print disassembly to.
    126     ///
    127     /// @param[in] exc_context
    128     ///     The execution context to get the machine code from.
    129     ///
    130     /// @return
    131     ///     The error generated.  If .Success() is true, disassembly succeeded.
    132     //------------------------------------------------------------------
    133     Error
    134     DisassembleFunction (Stream &stream,
    135                          ExecutionContext &exe_ctx);
    136 
    137 private:
    138     ClangExpression &                       m_expr;                 ///< The expression to be parsed
    139     std::unique_ptr<llvm::LLVMContext>       m_llvm_context;         ///< The LLVM context to generate IR into
    140     std::unique_ptr<clang::FileManager>      m_file_manager;         ///< The Clang file manager object used by the compiler
    141     std::unique_ptr<clang::CompilerInstance> m_compiler;             ///< The Clang compiler used to parse expressions into IR
    142     std::unique_ptr<clang::Builtin::Context> m_builtin_context;      ///< Context for Clang built-ins
    143     std::unique_ptr<clang::SelectorTable>    m_selector_table;       ///< Selector table for Objective-C methods
    144     std::unique_ptr<clang::ASTContext>       m_ast_context;          ///< The AST context used to hold types and names for the parser
    145     std::unique_ptr<clang::CodeGenerator>    m_code_generator;       ///< The Clang object that generates IR
    146     std::unique_ptr<IRExecutionUnit>         m_execution_unit;       ///< The container for the finished Module
    147 };
    148 
    149 }
    150 
    151 #endif  // liblldb_ClangExpressionParser_h_
    152