DWARFVerifier.h

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//===- DWARFVerifier.h ----------------------------------------------------===//
//
// 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 LLVM_DEBUGINFO_DWARF_DWARFVERIFIER_H
#define LLVM_DEBUGINFO_DWARF_DWARFVERIFIER_H
 
#include "llvm/ADT/STLFunctionalExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
#include "llvm/DebugInfo/DWARF/DWARFAddressRange.h"
#include "llvm/DebugInfo/DWARF/DWARFDie.h"
#include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
#include "llvm/DebugInfo/DWARF/LowLevel/DWARFExpression.h"
#include "llvm/Support/Compiler.h"
#include <cstdint>
#include <map>
#include <mutex>
#include <set>
 
namespace llvm {
class raw_ostream;
struct DWARFAddressRange;
class DWARFUnit;
class DWARFUnitVector;
struct DWARFAttribute;
class DWARFContext;
class DWARFDataExtractor;
class DWARFDebugAbbrev;
class DataExtractor;
struct DWARFSection;
 
struct AggregationData {
  unsigned OverallCount;
  std::map<std::string, unsigned> DetailedCounts;
};
 
class OutputCategoryAggregator {
private:
  std::mutex WriteMutex;
  std::map<std::string, AggregationData, std::less<>> Aggregation;
  uint64_t NumErrors = 0;
  bool IncludeDetail;
 
public:
  OutputCategoryAggregator(bool includeDetail = false)
      : IncludeDetail(includeDetail) {}
  void ShowDetail(bool showDetail) { IncludeDetail = showDetail; }
  size_t GetNumCategories() const { return Aggregation.size(); }
  LLVM_ABI void Report(StringRef category, function_ref<void()> detailCallback);
  LLVM_ABI void Report(StringRef category, StringRef sub_category,
                       function_ref<void()> detailCallback);
  LLVM_ABI void
  EnumerateResults(function_ref<void(StringRef, unsigned)> handleCounts);
  LLVM_ABI void EnumerateDetailedResultsFor(
      StringRef category, function_ref<void(StringRef, unsigned)> handleCounts);
  /// Return the number of errors that have been reported.
  uint64_t GetNumErrors() const { return NumErrors; }
};
 
/// A class that verifies DWARF debug information given a DWARF Context.
class DWARFVerifier {
public:
  /// A class that keeps the address range information for a single DIE.
  struct DieRangeInfo {
    DWARFDie Die;
 
    /// Sorted DWARFAddressRanges.
    std::vector<DWARFAddressRange> Ranges;
 
    /// Sorted DWARFAddressRangeInfo.
    std::set<DieRangeInfo> Children;
 
    DieRangeInfo() = default;
    DieRangeInfo(DWARFDie Die) : Die(Die) {}
 
    /// Used for unit testing.
    DieRangeInfo(std::vector<DWARFAddressRange> Ranges)
        : Ranges(std::move(Ranges)) {}
 
    typedef std::set<DieRangeInfo>::const_iterator die_range_info_iterator;
 
    /// Inserts the address range. If the range overlaps with an existing
    /// range, the range that it overlaps with will be returned and the two
    /// address ranges will be unioned together in "Ranges". If a duplicate
    /// entry is attempted to be added, the duplicate range will not actually be
    /// added and the returned iterator will point to end().
    ///
    /// This is used for finding overlapping ranges in the DW_AT_ranges
    /// attribute of a DIE. It is also used as a set of address ranges that
    /// children address ranges must all be contained in.
    LLVM_ABI std::optional<DWARFAddressRange>
    insert(const DWARFAddressRange &R);
 
    /// Inserts the address range info. If any of its ranges overlaps with a
    /// range in an existing range info, the range info is *not* added and an
    /// iterator to the overlapping range info. If a duplicate entry is
    /// attempted to be added, the duplicate range will not actually be added
    /// and the returned iterator will point to end().
    ///
    /// This is used for finding overlapping children of the same DIE.
    LLVM_ABI die_range_info_iterator insert(const DieRangeInfo &RI);
 
    /// Return true if ranges in this object contains all ranges within RHS.
    LLVM_ABI bool contains(const DieRangeInfo &RHS) const;
 
    /// Return true if any range in this object intersects with any range in
    /// RHS. Identical ranges are not considered to be intersecting.
    LLVM_ABI bool intersects(const DieRangeInfo &RHS) const;
  };
 
private:
  raw_ostream &OS;
  DWARFContext &DCtx;
  DIDumpOptions DumpOpts;
  uint32_t NumDebugLineErrors = 0;
  OutputCategoryAggregator ErrorCategory;
  // Used to relax some checks that do not currently work portably
  bool IsObjectFile;
  bool IsMachOObject;
  using ReferenceMap = std::map<uint64_t, std::set<uint64_t>>;
  std::mutex AccessMutex;
 
  raw_ostream &error() const;
  raw_ostream &warn() const;
  raw_ostream &note() const;
  raw_ostream &dump(const DWARFDie &Die, unsigned indent = 0) const;
 
  /// Verifies the abbreviations section.
  ///
  /// This function currently checks that:
  /// --No abbreviation declaration has more than one attributes with the same
  /// name.
  ///
  /// \param Abbrev Pointer to the abbreviations section we are verifying
  /// Abbrev can be a pointer to either .debug_abbrev or debug_abbrev.dwo.
  ///
  /// \returns The number of errors that occurred during verification.
  unsigned verifyAbbrevSection(const DWARFDebugAbbrev *Abbrev);
 
  /// Verifies the header of a unit in a .debug_info or .debug_types section.
  ///
  /// This function currently checks for:
  /// - Unit is in 32-bit DWARF format. The function can be modified to
  /// support 64-bit format.
  /// - The DWARF version is valid
  /// - The unit type is valid (if unit is in version >=5)
  /// - The unit doesn't extend beyond the containing section
  /// - The address size is valid
  /// - The offset in the .debug_abbrev section is valid
  ///
  /// \param DebugInfoData The section data
  /// \param Offset A reference to the offset start of the unit. The offset will
  /// be updated to point to the next unit in the section
  /// \param UnitIndex The index of the unit to be verified
  /// \param UnitType A reference to the type of the unit
  /// \param isUnitDWARF64 A reference to a flag that shows whether the unit is
  /// in 64-bit format.
  ///
  /// \returns true if the header is verified successfully, false otherwise.
  bool verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
                        uint64_t *Offset, unsigned UnitIndex, uint8_t &UnitType,
                        bool &isUnitDWARF64);
  bool verifyName(const DWARFDie &Die);
 
  /// Verifies the header of a unit in a .debug_info or .debug_types section.
  ///
  /// This function currently verifies:
  ///  - The debug info attributes.
  ///  - The debug info form=s.
  ///  - The presence of a root DIE.
  ///  - That the root DIE is a unit DIE.
  ///  - If a unit type is provided, that the unit DIE matches the unit type.
  ///  - The DIE ranges.
  ///  - That call site entries are only nested within subprograms with a
  ///    DW_AT_call attribute.
  ///
  /// \param Unit      The DWARF Unit to verify.
  ///
  /// \returns The number of errors that occurred during verification.
  unsigned verifyUnitContents(DWARFUnit &Unit,
                              ReferenceMap &UnitLocalReferences,
                              ReferenceMap &CrossUnitReferences);
 
  /// Verifies the unit headers and contents in a .debug_info or .debug_types
  /// section.
  ///
  /// \param S           The DWARF Section to verify.
  ///
  /// \returns The number of errors that occurred during verification.
  unsigned verifyUnitSection(const DWARFSection &S);
  unsigned verifyUnits(const DWARFUnitVector &Units);
 
  unsigned verifyIndex(StringRef Name, DWARFSectionKind SectionKind,
                       StringRef Index);
 
  /// Verifies that a call site entry is nested within a subprogram with a
  /// DW_AT_call attribute.
  ///
  /// \returns Number of errors that occurred during verification.
  unsigned verifyDebugInfoCallSite(const DWARFDie &Die);
 
  /// Verify that all Die ranges are valid.
  ///
  /// This function currently checks for:
  /// - cases in which lowPC >= highPC
  ///
  /// \returns Number of errors that occurred during verification.
  unsigned verifyDieRanges(const DWARFDie &Die, DieRangeInfo &ParentRI);
 
  /// 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
  ///
  /// \returns NumErrors The number of errors occurred during verification of
  /// attributes' values in a unit
  unsigned 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 section 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
  ///
  /// \returns NumErrors The number of errors occurred during verification of
  /// attributes' forms in a unit
  unsigned verifyDebugInfoForm(const DWARFDie &Die, DWARFAttribute &AttrValue,
                               ReferenceMap &UnitLocalReferences,
                               ReferenceMap &CrossUnitReferences);
 
  /// 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.
  ///
  /// \returns NumErrors The number of errors occurred during verification of
  /// references for the .debug_info and .debug_types sections
  unsigned verifyDebugInfoReferences(
      const ReferenceMap &,
      llvm::function_ref<DWARFUnit *(uint64_t)> GetUnitForDieOffset);
 
  /// Verify 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();
 
  /// Verify that an Apple-style accelerator table is valid.
  ///
  /// This function currently checks that:
  /// - The fixed part of the header fits in the section
  /// - The size of the section is as large as what the header describes
  /// - There is at least one atom
  /// - The form for each atom is valid
  /// - The tag for each DIE in the table is valid
  /// - The buckets have a valid index, or they are empty
  /// - Each hashdata offset is valid
  /// - Each DIE is valid
  ///
  /// \param AccelSection pointer to the section containing the acceleration table
  /// \param StrData pointer to the string section
  /// \param SectionName the name of the table we're verifying
  ///
  /// \returns The number of errors occurred during verification
  void verifyAppleAccelTable(const DWARFSection *AccelSection,
                             DataExtractor *StrData, const char *SectionName);
 
  void verifyDebugNamesCULists(const DWARFDebugNames &AccelTable);
  void verifyNameIndexBuckets(const DWARFDebugNames::NameIndex &NI,
                              const DataExtractor &StrData);
  void verifyNameIndexAbbrevs(const DWARFDebugNames::NameIndex &NI);
  void verifyNameIndexAttribute(const DWARFDebugNames::NameIndex &NI,
                                const DWARFDebugNames::Abbrev &Abbr,
                                DWARFDebugNames::AttributeEncoding AttrEnc);
  void verifyNameIndexEntries(
      const DWARFDebugNames::NameIndex &NI,
      const DWARFDebugNames::NameTableEntry &NTE,
      const DenseMap<uint64_t, DWARFUnit *> &CUOffsetsToDUMap);
  void verifyNameIndexCompleteness(
      const DWARFDie &Die, const DWARFDebugNames::NameIndex &NI,
      const StringMap<DenseSet<uint64_t>> &NamesToDieOffsets);
 
  /// Verify that the DWARF v5 accelerator table is valid.
  ///
  /// This function currently checks that:
  /// - Headers individual Name Indices fit into the section and can be parsed.
  /// - Abbreviation tables can be parsed and contain valid index attributes
  ///   with correct form encodings.
  /// - The CU lists reference existing compile units.
  /// - The buckets have a valid index, or they are empty.
  /// - All names are reachable via the hash table (they have the correct hash,
  ///   and the hash is in the correct bucket).
  /// - Information in the index entries is complete (all required entries are
  ///   present) and consistent with the debug_info section DIEs.
  ///
  /// \param AccelSection section containing the acceleration table
  /// \param StrData string section
  ///
  /// \returns The number of errors occurred during verification
  void verifyDebugNames(const DWARFSection &AccelSection,
                        const DataExtractor &StrData);
 
  /// Verify that the the expression is valid within the context of unit U.
  ///
  /// \param E expression to verify.
  /// \param U containing DWARFUnit, if any.
  ///
  /// returns true if E is a valid expression.
  bool verifyExpression(const DWARFExpression &E, DWARFUnit *U);
 
  /// Verify that the the expression operation is valid within the context of
  /// unit U.
  ///
  /// \param Op operation to verify
  /// \param U containing DWARFUnit, if any
  ///
  /// returns true if Op is a valid Dwarf operation
  bool verifyExpressionOp(const DWARFExpression::Operation &Op, DWARFUnit *U);
 
public:
  LLVM_ABI
  DWARFVerifier(raw_ostream &S, DWARFContext &D,
                DIDumpOptions DumpOpts = DIDumpOptions::getForSingleDIE());
 
  /// Verify the information in any of the following sections, if available:
  /// .debug_abbrev, debug_abbrev.dwo
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if .debug_abbrev and .debug_abbrev.dwo verify successfully,
  /// false otherwise.
  LLVM_ABI bool handleDebugAbbrev();
 
  /// Verify the information in the .debug_info and .debug_types sections.
  ///
  /// Any errors are reported to the stream that this object was
  /// constructed with.
  ///
  /// \returns true if all sections verify successfully, false otherwise.
  LLVM_ABI bool handleDebugInfo();
 
  /// Verify the information in the .debug_cu_index section.
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the .debug_cu_index verifies successfully, false
  /// otherwise.
  LLVM_ABI bool handleDebugCUIndex();
 
  /// Verify the information in the .debug_tu_index section.
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the .debug_tu_index verifies successfully, false
  /// otherwise.
  LLVM_ABI bool handleDebugTUIndex();
 
  /// 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.
  LLVM_ABI bool handleDebugLine();
 
  /// Verify the information in accelerator tables, if they exist.
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the existing Apple-style accelerator tables verify
  /// successfully, false otherwise.
  LLVM_ABI bool handleAccelTables();
 
  /// Verify the information in the .debug_str_offsets[.dwo].
  ///
  /// Any errors are reported to the stream that was this object was
  /// constructed with.
  ///
  /// \returns true if the .debug_line verifies successfully, false otherwise.
  LLVM_ABI bool handleDebugStrOffsets();
  LLVM_ABI bool
  verifyDebugStrOffsets(std::optional<dwarf::DwarfFormat> LegacyFormat,
                        StringRef SectionName, const DWARFSection &Section,
                        StringRef StrData);
 
  /// Emits any aggregate information collected, depending on the dump options
  LLVM_ABI void summarize();
};
 
static inline bool operator<(const DWARFVerifier::DieRangeInfo &LHS,
                             const DWARFVerifier::DieRangeInfo &RHS) {
  return std::tie(LHS.Ranges, LHS.Die) < std::tie(RHS.Ranges, RHS.Die);
}
 
} // end namespace llvm
 
#endif // LLVM_DEBUGINFO_DWARF_DWARFVERIFIER_H