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/BinaryFormat/Dwarf.h" 13 #include "llvm/DebugInfo/DWARF/DWARFSection.h" 14 #include "llvm/Support/DataExtractor.h" 15 16 namespace llvm { 17 class DWARFObject; 18 19 /// A DataExtractor (typically for an in-memory copy of an object-file section) 20 /// plus a relocation map for that section, if there is one. 21 class DWARFDataExtractor : public DataExtractor { 22 const DWARFObject *Obj = nullptr; 23 const DWARFSection *Section = nullptr; 24 25 public: 26 /// Constructor for the normal case of extracting data from a DWARF section. 27 /// The DWARFSection's lifetime must be at least as long as the extractor's. 28 DWARFDataExtractor(const DWARFObject &Obj, const DWARFSection &Section, 29 bool IsLittleEndian, uint8_t AddressSize) 30 : DataExtractor(Section.Data, IsLittleEndian, AddressSize), Obj(&Obj), 31 Section(&Section) {} 32 33 /// Constructor for cases when there are no relocations. 34 DWARFDataExtractor(StringRef Data, bool IsLittleEndian, uint8_t AddressSize) 35 : DataExtractor(Data, IsLittleEndian, AddressSize) {} 36 DWARFDataExtractor(ArrayRef<uint8_t> Data, bool IsLittleEndian, 37 uint8_t AddressSize) 38 : DataExtractor( 39 StringRef(reinterpret_cast<const char *>(Data.data()), Data.size()), 40 IsLittleEndian, AddressSize) {} 41 42 /// Truncating constructor 43 DWARFDataExtractor(const DWARFDataExtractor &Other, size_t Length) 44 : DataExtractor(Other.getData().substr(0, Length), Other.isLittleEndian(), 45 Other.getAddressSize()), 46 Obj(Other.Obj), Section(Other.Section) {} 47 48 /// Extracts the DWARF "initial length" field, which can either be a 32-bit 49 /// value smaller than 0xfffffff0, or the value 0xffffffff followed by a 50 /// 64-bit length. Returns the actual length, and the DWARF format which is 51 /// encoded in the field. In case of errors, it returns {0, DWARF32} and 52 /// leaves the offset unchanged. 53 std::pair<uint64_t, dwarf::DwarfFormat> 54 getInitialLength(uint64_t *Off, Error *Err = nullptr) const; 55 56 std::pair<uint64_t, dwarf::DwarfFormat> getInitialLength(Cursor &C) const { 57 return getInitialLength(&getOffset(C), &getError(C)); 58 } 59 60 /// Extracts a value and applies a relocation to the result if 61 /// one exists for the given offset. 62 uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off, 63 uint64_t *SectionIndex = nullptr, 64 Error *Err = nullptr) const; 65 uint64_t getRelocatedValue(Cursor &C, uint32_t Size, 66 uint64_t *SectionIndex = nullptr) const { 67 return getRelocatedValue(Size, &getOffset(C), SectionIndex, &getError(C)); 68 } 69 70 /// Extracts an address-sized value and applies a relocation to the result if 71 /// one exists for the given offset. 72 uint64_t getRelocatedAddress(uint64_t *Off, uint64_t *SecIx = nullptr) const { 73 return getRelocatedValue(getAddressSize(), Off, SecIx); 74 } 75 uint64_t getRelocatedAddress(Cursor &C, uint64_t *SecIx = nullptr) const { 76 return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx, 77 &getError(C)); 78 } 79 80 /// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding. 81 /// There is a DWARF encoding that uses a PC-relative adjustment. 82 /// For these values, \p AbsPosOffset is used to fix them, which should 83 /// reflect the absolute address of this pointer. 84 Optional<uint64_t> getEncodedPointer(uint64_t *Offset, uint8_t Encoding, 85 uint64_t AbsPosOffset = 0) const; 86 }; 87 88 } // end namespace llvm 89 90 #endif // LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H 91