include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h

   1 //===- DWARFDataExtractor.h -------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
  10 #define LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
  11
  12 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
  13 #include "llvm/Support/DataExtractor.h"
  14
  15 namespace llvm {
  16 class DWARFObject;
  17
  18 /// A DataExtractor (typically for an in-memory copy of an object-file section)
  19 /// plus a relocation map for that section, if there is one.
  20 class DWARFDataExtractor : public DataExtractor {
  21   const DWARFObject *Obj = nullptr;
  22   const DWARFSection *Section = nullptr;
  23
  24 public:
  25   /// Constructor for the normal case of extracting data from a DWARF section.
  26   /// The DWARFSection's lifetime must be at least as long as the extractor's.
  27   DWARFDataExtractor(const DWARFObject &Obj, const DWARFSection &Section,
  28                      bool IsLittleEndian, uint8_t AddressSize)
  29       : DataExtractor(Section.Data, IsLittleEndian, AddressSize), Obj(&Obj),
  30         Section(&Section) {}
  31
  32   /// Constructor for cases when there are no relocations.
  33   DWARFDataExtractor(StringRef Data, bool IsLittleEndian, uint8_t AddressSize)
  34     : DataExtractor(Data, IsLittleEndian, AddressSize) {}
  35
  36   /// Extracts a value and applies a relocation to the result if
  37   /// one exists for the given offset.
  38   uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off,
  39                              uint64_t *SectionIndex = nullptr,
  40                              Error *Err = nullptr) const;
  41
  42   /// Extracts an address-sized value and applies a relocation to the result if
  43   /// one exists for the given offset.
  44   uint64_t getRelocatedAddress(uint64_t *Off, uint64_t *SecIx = nullptr) const {
  45     return getRelocatedValue(getAddressSize(), Off, SecIx);
  46   }
  47   uint64_t getRelocatedAddress(Cursor &C, uint64_t *SecIx = nullptr) const {
  48     return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx,
  49                              &getError(C));
  50   }
  51
  52   /// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding.
  53   /// There is a DWARF encoding that uses a PC-relative adjustment.
  54   /// For these values, \p AbsPosOffset is used to fix them, which should
  55   /// reflect the absolute address of this pointer.
  56   Optional<uint64_t> getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
  57                                        uint64_t AbsPosOffset = 0) const;
  58
  59   size_t size() const { return Section == nullptr ? 0 : Section->Data.size(); }
  60 };
  61
  62 } // end namespace llvm
  63
  64 #endif // LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H