DWARFExpressionList.h

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//===-- DWARFExpressionList.h -----------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#ifndef LLDB_EXPRESSION_DWARFEXPRESSIONLIST_H
#define LLDB_EXPRESSION_DWARFEXPRESSIONLIST_H
 
#include "lldb/Core/AddressRange.h"
#include "lldb/Core/Value.h"
#include "lldb/Expression/DWARFExpression.h"
#include "lldb/Utility/RangeMap.h"
#include "lldb/lldb-private.h"
 
namespace lldb_private {
 
/// \class DWARFExpressionList DWARFExpressionList.h
/// "lldb/Expression/DWARFExpressionList.h" Encapsulates a range map from file
/// address range to a single DWARF location expression.
class DWARFExpressionList {
public:
  DWARFExpressionList() = default;
 
  DWARFExpressionList(lldb::ModuleSP module_sp,
                      const DWARFExpression::Delegate *dwarf_cu,
                      lldb::addr_t func_file_addr)
      : m_module_wp(module_sp), m_dwarf_cu(dwarf_cu),
        m_func_file_addr(func_file_addr) {}
 
  DWARFExpressionList(lldb::ModuleSP module_sp, DWARFExpression expr,
                      const DWARFExpression::Delegate *dwarf_cu)
      : m_module_wp(module_sp), m_dwarf_cu(dwarf_cu) {
    AddExpression(0, LLDB_INVALID_ADDRESS, expr);
  }
 
  /// Return true if the location expression contains data
  bool IsValid() const { return !m_exprs.IsEmpty(); }
 
  void Clear() { m_exprs.Clear(); }
 
  // Return true if the location expression is always valid.
  bool IsAlwaysValidSingleExpr() const;
 
  bool AddExpression(lldb::addr_t base, lldb::addr_t end, DWARFExpression expr);
 
  /// Get the expression data at the file address.
  bool GetExpressionData(DataExtractor &data,
                         lldb::addr_t func_load_addr = LLDB_INVALID_ADDRESS,
                         lldb::addr_t file_addr = 0) const;
 
  /// Sort m_expressions.
  void Sort() { m_exprs.Sort(); }
 
  void SetFuncFileAddress(lldb::addr_t func_file_addr) {
    m_func_file_addr = func_file_addr;
  }
 
  lldb::addr_t GetFuncFileAddress() { return m_func_file_addr; }
 
  /// Represents an entry in the DWARFExpressionList with all needed metadata.
  struct DWARFExpressionEntry {
    /// Represents a DWARF location range in the DWARF unit’s file‐address space
    std::optional<AddressRange> file_range; ///< None = always-valid single expr
    const DWARFExpression *expr;
  };
 
  /// Returns a DWARFExpressionEntry whose file_range contains the given
  /// load‐address.  `func_load_addr` is the load‐address of the function
  /// start; `load_addr` is the full runtime PC.  On success, `expr` is
  /// non-null.
  std::optional<DWARFExpressionEntry>
  GetExpressionEntryAtAddress(lldb::addr_t func_load_addr,
                              lldb::addr_t load_addr) const;
 
  const DWARFExpression *GetExpressionAtAddress(lldb::addr_t func_load_addr,
                                                lldb::addr_t load_addr) const;
 
  const DWARFExpression *GetAlwaysValidExpr() const;
 
  DWARFExpression *GetMutableExpressionAtAddress(
      lldb::addr_t func_load_addr = LLDB_INVALID_ADDRESS,
      lldb::addr_t load_addr = 0);
 
  size_t GetSize() const { return m_exprs.GetSize(); }
 
  bool ContainsThreadLocalStorage() const;
 
  bool LinkThreadLocalStorage(
      lldb::ModuleSP new_module_sp,
      std::function<lldb::addr_t(lldb::addr_t file_addr)> const
          &link_address_callback);
 
  bool MatchesOperand(StackFrame &frame,
                      const Instruction::Operand &operand) const;
 
  /// Dump locations that contains file_addr if it's valid. Otherwise. dump all
  /// locations.
  bool DumpLocations(Stream *s, lldb::DescriptionLevel level,
                     lldb::addr_t func_load_addr, lldb::addr_t file_addr,
                     ABI *abi) const;
 
  /// Dump all locaitons with each separated by new line.
  void GetDescription(Stream *s, lldb::DescriptionLevel level, ABI *abi) const;
 
  /// Search for a load address in the dwarf location list
  ///
  /// \param[in] func_load_addr
  ///     The actual address of the function containing this location list.
  ///
  /// \param[in] addr
  ///     The address to resolve.
  ///
  /// \return
  ///     True if IsLocationList() is true and the address was found;
  ///     false otherwise.
  bool ContainsAddress(lldb::addr_t func_load_addr, lldb::addr_t addr) const;
 
  void SetModule(const lldb::ModuleSP &module) { m_module_wp = module; }
 
  llvm::Expected<Value> Evaluate(ExecutionContext *exe_ctx,
                                 RegisterContext *reg_ctx,
                                 lldb::addr_t func_load_addr,
                                 const Value *initial_value_ptr,
                                 const Value *object_address_ptr) const;
 
private:
  // RangeDataVector requires a comparator for DWARFExpression, but it doesn't
  // make sense to do so.
  struct DWARFExpressionCompare {
  public:
    bool operator()(const DWARFExpression &lhs,
                    const DWARFExpression &rhs) const {
      return false;
    }
  };
  using ExprVec = RangeDataVector<lldb::addr_t, lldb::addr_t, DWARFExpression,
                                  0, DWARFExpressionCompare>;
  using Entry = ExprVec::Entry;
 
  // File address range mapping to single dwarf expression.
  ExprVec m_exprs;
 
  /// Module which defined this expression.
  lldb::ModuleWP m_module_wp;
 
  /// The DWARF compile unit this expression belongs to. It is used to evaluate
  /// values indexing into the .debug_addr section (e.g. DW_OP_GNU_addr_index,
  /// DW_OP_GNU_const_index)
  const DWARFExpression::Delegate *m_dwarf_cu = nullptr;
 
  // Function base file address.
  lldb::addr_t m_func_file_addr = LLDB_INVALID_ADDRESS;
 
  using const_iterator = ExprVec::Collection::const_iterator;
  const_iterator begin() const { return m_exprs.begin(); }
  const_iterator end() const { return m_exprs.end(); }
};
} // namespace lldb_private
 
#endif // LLDB_EXPRESSION_DWARFEXPRESSIONLIST_H