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//===- DWARFDataExtractor.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 LLVM_DEBUGINFO_DWARF_DWARFDATAEXTRACTOR_H
#define LLVM_DEBUGINFO_DWARF_DWARFDATAEXTRACTOR_H
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/Support/DataExtractor.h"
namespace llvm {
class DWARFObject;
/// A DataExtractor (typically for an in-memory copy of an object-file section)
/// plus a relocation map for that section, if there is one.
class DWARFDataExtractor : public DataExtractor {
const DWARFObject *Obj = nullptr;
const DWARFSection *Section = nullptr;
public:
/// Constructor for the normal case of extracting data from a DWARF section.
/// The DWARFSection's lifetime must be at least as long as the extractor's.
DWARFDataExtractor(const DWARFObject &Obj, const DWARFSection &Section,
bool IsLittleEndian, uint8_t AddressSize)
: DataExtractor(Section.Data, IsLittleEndian, AddressSize), Obj(&Obj),
Section(&Section) {}
/// Constructor for cases when there are no relocations.
DWARFDataExtractor(StringRef Data, bool IsLittleEndian, uint8_t AddressSize)
: DataExtractor(Data, IsLittleEndian, AddressSize) {}
DWARFDataExtractor(ArrayRef<uint8_t> Data, bool IsLittleEndian,
uint8_t AddressSize)
: DataExtractor(
StringRef(reinterpret_cast<const char *>(Data.data()), Data.size()),
IsLittleEndian, AddressSize) {}
/// Truncating constructor
DWARFDataExtractor(const DWARFDataExtractor &Other, size_t Length)
: DataExtractor(Other.getData().substr(0, Length), Other.isLittleEndian(),
Other.getAddressSize()),
Obj(Other.Obj), Section(Other.Section) {}
/// Extracts the DWARF "initial length" field, which can either be a 32-bit
/// value smaller than 0xfffffff0, or the value 0xffffffff followed by a
/// 64-bit length. Returns the actual length, and the DWARF format which is
/// encoded in the field. In case of errors, it returns {0, DWARF32} and
/// leaves the offset unchanged.
std::pair<uint64_t, dwarf::DwarfFormat>
getInitialLength(uint64_t *Off, Error *Err = nullptr) const;
std::pair<uint64_t, dwarf::DwarfFormat> getInitialLength(Cursor &C) const {
return getInitialLength(&getOffset(C), &getError(C));
}
/// Extracts a value and applies a relocation to the result if
/// one exists for the given offset.
uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off,
uint64_t *SectionIndex = nullptr,
Error *Err = nullptr) const;
uint64_t getRelocatedValue(Cursor &C, uint32_t Size,
uint64_t *SectionIndex = nullptr) const {
return getRelocatedValue(Size, &getOffset(C), SectionIndex, &getError(C));
}
/// Extracts an address-sized value and applies a relocation to the result if
/// one exists for the given offset.
uint64_t getRelocatedAddress(uint64_t *Off, uint64_t *SecIx = nullptr) const {
return getRelocatedValue(getAddressSize(), Off, SecIx);
}
uint64_t getRelocatedAddress(Cursor &C, uint64_t *SecIx = nullptr) const {
return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx,
&getError(C));
}
/// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding.
/// There is a DWARF encoding that uses a PC-relative adjustment.
/// For these values, \p AbsPosOffset is used to fix them, which should
/// reflect the absolute address of this pointer.
std::optional<uint64_t> getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
uint64_t AbsPosOffset = 0) const;
};
} // end namespace llvm
#endif // LLVM_DEBUGINFO_DWARF_DWARFDATAEXTRACTOR_H
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