//===- DWARFAbbreviationDeclaration.h ---------------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// #ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H #define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H #include "llvm/ADT/Optional.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/iterator_range.h" #include "llvm/BinaryFormat/Dwarf.h" #include "llvm/Support/DataExtractor.h" #include <cassert> #include <cstddef> #include <cstdint> namespace llvm { class DWARFFormValue; class DWARFUnit; class raw_ostream; class DWARFAbbreviationDeclaration { public: struct AttributeSpec { AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<int64_t> V) : Attr(A), Form(F), ByteSizeOrValue(V) {} dwarf::Attribute Attr; dwarf::Form Form; /// The following field is used for ByteSize for non-implicit_const /// attributes and as value for implicit_const ones, indicated by /// Form == DW_FORM_implicit_const. /// The following cases are distinguished: /// * Form != DW_FORM_implicit_const and ByteSizeOrValue has a value: /// ByteSizeOrValue contains the fixed size in bytes /// for the Form in this object. /// * Form != DW_FORM_implicit_const and ByteSizeOrValue is None: /// byte size of Form either varies according to the DWARFUnit /// that it is contained in or the value size varies and must be /// decoded from the debug information in order to determine its size. /// * Form == DW_FORM_implicit_const: /// ByteSizeOrValue contains value for the implicit_const attribute. Optional<int64_t> ByteSizeOrValue; bool isImplicitConst() const { return Form == dwarf::DW_FORM_implicit_const; } /// Get the fixed byte size of this Form if possible. This function might /// use the DWARFUnit to calculate the size of the Form, like for /// DW_AT_address and DW_AT_ref_addr, so this isn't just an accessor for /// the ByteSize member. Optional<int64_t> getByteSize(const DWARFUnit &U) const; }; typedef SmallVector<AttributeSpec, 8> AttributeSpecVector; DWARFAbbreviationDeclaration(); uint32_t getCode() const { return Code; } uint8_t getCodeByteSize() const { return CodeByteSize; } dwarf::Tag getTag() const { return Tag; } bool hasChildren() const { return HasChildren; } typedef iterator_range<AttributeSpecVector::const_iterator> attr_iterator_range; attr_iterator_range attributes() const { return attr_iterator_range(AttributeSpecs.begin(), AttributeSpecs.end()); } dwarf::Form getFormByIndex(uint32_t idx) const { assert(idx < AttributeSpecs.size()); return AttributeSpecs[idx].Form; } size_t getNumAttributes() const { return AttributeSpecs.size(); } dwarf::Attribute getAttrByIndex(uint32_t idx) const { assert(idx < AttributeSpecs.size()); return AttributeSpecs[idx].Attr; } /// Get the index of the specified attribute. /// /// Searches the this abbreviation declaration for the index of the specified /// attribute. /// /// \param attr DWARF attribute to search for. /// \returns Optional index of the attribute if found, None otherwise. Optional<uint32_t> findAttributeIndex(dwarf::Attribute attr) const; /// Extract a DWARF form value from a DIE specified by DIE offset. /// /// Extract an attribute value for a DWARFUnit given the DIE offset and the /// attribute. /// /// \param DIEOffset the DIE offset that points to the ULEB128 abbreviation /// code in the .debug_info data. /// \param Attr DWARF attribute to search for. /// \param U the DWARFUnit the contains the DIE. /// \returns Optional DWARF form value if the attribute was extracted. Optional<DWARFFormValue> getAttributeValue(const uint32_t DIEOffset, const dwarf::Attribute Attr, const DWARFUnit &U) const; bool extract(DataExtractor Data, uint32_t* OffsetPtr); void dump(raw_ostream &OS) const; // Return an optional byte size of all attribute data in this abbreviation // if a constant byte size can be calculated given a DWARFUnit. This allows // DWARF parsing to be faster as many DWARF DIEs have a fixed byte size. Optional<size_t> getFixedAttributesByteSize(const DWARFUnit &U) const; private: void clear(); /// A helper structure that can quickly determine the size in bytes of an /// abbreviation declaration. struct FixedSizeInfo { /// The fixed byte size for fixed size forms. uint16_t NumBytes = 0; /// Number of DW_FORM_address forms in this abbrevation declaration. uint8_t NumAddrs = 0; /// Number of DW_FORM_ref_addr forms in this abbrevation declaration. uint8_t NumRefAddrs = 0; /// Number of 4 byte in DWARF32 and 8 byte in DWARF64 forms. uint8_t NumDwarfOffsets = 0; FixedSizeInfo() = default; /// Calculate the fixed size in bytes given a DWARFUnit. /// /// \param U the DWARFUnit to use when determing the byte size. /// \returns the size in bytes for all attribute data in this abbreviation. /// The returned size does not include bytes for the ULEB128 abbreviation /// code size_t getByteSize(const DWARFUnit &U) const; }; uint32_t Code; dwarf::Tag Tag; uint8_t CodeByteSize; bool HasChildren; AttributeSpecVector AttributeSpecs; /// If this abbreviation has a fixed byte size then FixedAttributeSize member /// variable below will have a value. Optional<FixedSizeInfo> FixedAttributeSize; }; } // end namespace llvm #endif // LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H