//===-- ClangExpressionParser.h ---------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef liblldb_ClangExpressionParser_h_
#define liblldb_ClangExpressionParser_h_

#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/ClangForward.h"
#include "lldb/Expression/DiagnosticManager.h"
#include "lldb/Expression/ExpressionParser.h"
#include "lldb/Utility/Status.h"
#include "lldb/lldb-public.h"

#include <string>
#include <vector>

namespace lldb_private {

class IRExecutionUnit;

//----------------------------------------------------------------------
/// @class ClangExpressionParser ClangExpressionParser.h
/// "lldb/Expression/ClangExpressionParser.h"
/// @brief Encapsulates an instance of Clang that can parse expressions.
///
/// ClangExpressionParser is responsible for preparing an instance of
/// ClangExpression for execution.  ClangExpressionParser uses ClangExpression
/// as a glorified parameter list, performing the required parsing and
/// conversion to formats (DWARF bytecode, or JIT compiled machine code)
/// that can be executed.
//----------------------------------------------------------------------
class ClangExpressionParser : public ExpressionParser {
public:
  //------------------------------------------------------------------
  /// Constructor
  ///
  /// Initializes class variables.
  ///
  /// @param[in] exe_scope,
  ///     If non-NULL, an execution context scope that can help to
  ///     correctly create an expression with a valid process for
  ///     optional tuning Objective-C runtime support. Can be NULL.
  ///
  /// @param[in] expr
  ///     The expression to be parsed.
  //------------------------------------------------------------------
  ClangExpressionParser(ExecutionContextScope *exe_scope, Expression &expr,
                        bool generate_debug_info);

  //------------------------------------------------------------------
  /// Destructor
  //------------------------------------------------------------------
  ~ClangExpressionParser() override;

  //------------------------------------------------------------------
  /// Parse a single expression and convert it to IR using Clang.  Don't
  /// wrap the expression in anything at all.
  ///
  /// @param[in] diagnostic_manager
  ///     The diagnostic manager to report errors to.
  ///
  /// @return
  ///     The number of errors encountered during parsing.  0 means
  ///     success.
  //------------------------------------------------------------------
  unsigned Parse(DiagnosticManager &diagnostic_manager) override;

  bool RewriteExpression(DiagnosticManager &diagnostic_manager) override;

  //------------------------------------------------------------------
  /// Ready an already-parsed expression for execution, possibly
  /// evaluating it statically.
  ///
  /// @param[out] func_addr
  ///     The address to which the function has been written.
  ///
  /// @param[out] func_end
  ///     The end of the function's allocated memory region.  (func_addr
  ///     and func_end do not delimit an allocated region; the allocated
  ///     region may begin before func_addr.)
  ///
  /// @param[in] execution_unit_sp
  ///     After parsing, ownership of the execution unit for
  ///     for the expression is handed to this shared pointer.
  ///
  /// @param[in] exe_ctx
  ///     The execution context to write the function into.
  ///
  /// @param[out] evaluated_statically
  ///     Set to true if the expression could be interpreted statically;
  ///     untouched otherwise.
  ///
  /// @param[out] const_result
  ///     If the result of the expression is constant, and the
  ///     expression has no side effects, this is set to the result of the
  ///     expression.
  ///
  /// @param[in] execution_policy
  ///     Determines whether the expression must be JIT-compiled, must be
  ///     evaluated statically, or whether this decision may be made
  ///     opportunistically.
  ///
  /// @return
  ///     An error code indicating the success or failure of the operation.
  ///     Test with Success().
  //------------------------------------------------------------------
  Status
  PrepareForExecution(lldb::addr_t &func_addr, lldb::addr_t &func_end,
                      lldb::IRExecutionUnitSP &execution_unit_sp,
                      ExecutionContext &exe_ctx, bool &can_interpret,
                      lldb_private::ExecutionPolicy execution_policy) override;

  //------------------------------------------------------------------
  /// Run all static initializers for an execution unit.
  ///
  /// @param[in] execution_unit_sp
  ///     The execution unit.
  ///
  /// @param[in] exe_ctx
  ///     The execution context to use when running them.  Thread can't be null.
  ///
  /// @return
  ///     The error code indicating the
  //------------------------------------------------------------------
  Status RunStaticInitializers(lldb::IRExecutionUnitSP &execution_unit_sp,
                               ExecutionContext &exe_ctx);

  //------------------------------------------------------------------
  /// Returns a string representing current ABI.
  ///
  /// @param[in] target_arch
  ///     The target architecture.
  ///
  /// @return
  ///     A string representing target ABI for the current architecture.
  //-------------------------------------------------------------------
  std::string GetClangTargetABI(const ArchSpec &target_arch);

private:
  std::unique_ptr<llvm::LLVMContext>
      m_llvm_context; ///< The LLVM context to generate IR into
  std::unique_ptr<clang::FileManager>
      m_file_manager; ///< The Clang file manager object used by the compiler
  std::unique_ptr<clang::CompilerInstance>
      m_compiler; ///< The Clang compiler used to parse expressions into IR
  std::unique_ptr<clang::Builtin::Context>
      m_builtin_context; ///< Context for Clang built-ins
  std::unique_ptr<clang::SelectorTable>
      m_selector_table; ///< Selector table for Objective-C methods
  std::unique_ptr<clang::CodeGenerator>
      m_code_generator; ///< The Clang object that generates IR

  class LLDBPreprocessorCallbacks;
  LLDBPreprocessorCallbacks *m_pp_callbacks; ///< Called when the preprocessor
                                             ///encounters module imports
  std::unique_ptr<ClangASTContext> m_ast_context;
};
}

#endif // liblldb_ClangExpressionParser_h_
