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

#ifndef LLVM_DEBUGINFO_DWARF_DWARFVERIFIER_H
#define LLVM_DEBUGINFO_DWARF_DWARFVERIFIER_H

#include <cstdint>
#include <map>
#include <set>

namespace llvm {
class raw_ostream;
struct DWARFAttribute;
class DWARFContext;
class DWARFDie;
class DWARFUnit;
class DWARFAcceleratorTable;

/// A class that verifies DWARF debug information given a DWARF Context.
class DWARFVerifier {
  raw_ostream &OS;
  DWARFContext &DCtx;
  /// A map that tracks all references (converted absolute references) so we
  /// can verify each reference points to a valid DIE and not an offset that
  /// lies between to valid DIEs.
  std::map<uint64_t, std::set<uint32_t>> ReferenceToDIEOffsets;
  uint32_t NumDebugInfoErrors = 0;
  uint32_t NumDebugLineErrors = 0;
  uint32_t NumAppleNamesErrors = 0;

  /// Verifies the attribute's DWARF attribute and its value.
  ///
  /// This function currently checks for:
  /// - DW_AT_ranges values is a valid .debug_ranges offset
  /// - DW_AT_stmt_list is a valid .debug_line offset
  ///
  /// \param Die          The DWARF DIE that owns the attribute value
  /// \param AttrValue    The DWARF attribute value to check
  void verifyDebugInfoAttribute(const DWARFDie &Die, DWARFAttribute &AttrValue);

  /// Verifies the attribute's DWARF form.
  ///
  /// This function currently checks for:
  /// - All DW_FORM_ref values that are CU relative have valid CU offsets
  /// - All DW_FORM_ref_addr values have valid .debug_info offsets
  /// - All DW_FORM_strp values have valid .debug_str offsets
  ///
  /// \param Die          The DWARF DIE that owns the attribute value
  /// \param AttrValue    The DWARF attribute value to check
  void verifyDebugInfoForm(const DWARFDie &Die, DWARFAttribute &AttrValue);

  /// Verifies the all valid references that were found when iterating through
  /// all of the DIE attributes.
  ///
  /// This function will verify that all references point to DIEs whose DIE
  /// offset matches. This helps to ensure if a DWARF link phase moved things
  /// around, that it doesn't create invalid references by failing to relocate
  /// CU relative and absolute references.
  void verifyDebugInfoReferences();

  /// Verify the the DW_AT_stmt_list encoding and value and ensure that no
  /// compile units that have the same DW_AT_stmt_list value.
  void verifyDebugLineStmtOffsets();

  /// Verify that all of the rows in the line table are valid.
  ///
  /// This function currently checks for:
  /// - addresses within a sequence that decrease in value
  /// - invalid file indexes
  void verifyDebugLineRows();

public:
  DWARFVerifier(raw_ostream &S, DWARFContext &D)
      : OS(S), DCtx(D) {}
  /// Verify the information in the .debug_info section.
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the .debug_info verifies successfully, false otherwise.
  bool handleDebugInfo();

  /// Verify the information in the .debug_line section.
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the .debug_line verifies successfully, false otherwise.
  bool handleDebugLine();

  /// Verify the information in the .apple_names accelerator table.
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the .apple_names verifies successfully, false otherwise.
  bool handleAppleNames();
};

} // end namespace llvm

#endif // LLVM_DEBUGINFO_DWARF_DWARFCONTEXT_H