Coverage Report

Created: 2018-07-12 09:57

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/DebugInfo/DWARF/DWARFDie.h
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//===- DWARFDie.h -----------------------------------------------*- C++ -*-===//
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//
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//                     The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_DEBUGINFO_DWARFDIE_H
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#define LLVM_DEBUGINFO_DWARFDIE_H
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/iterator.h"
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#include "llvm/ADT/iterator_range.h"
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#include "llvm/BinaryFormat/Dwarf.h"
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#include "llvm/DebugInfo/DIContext.h"
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#include "llvm/DebugInfo/DWARF/DWARFAddressRange.h"
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#include "llvm/DebugInfo/DWARF/DWARFAttribute.h"
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#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
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#include <cassert>
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#include <cstdint>
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#include <iterator>
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namespace llvm {
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class DWARFUnit;
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class raw_ostream;
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//===----------------------------------------------------------------------===//
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/// Utility class that carries the DWARF compile/type unit and the debug info
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/// entry in an object.
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///
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/// When accessing information from a debug info entry we always need to DWARF
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/// compile/type unit in order to extract the info correctly as some information
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/// is relative to the compile/type unit. Prior to this class the DWARFUnit and
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/// the DWARFDebugInfoEntry was passed around separately and there was the
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/// possibility for error if the wrong DWARFUnit was used to extract a unit
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/// relative offset. This class helps to ensure that this doesn't happen and
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/// also simplifies the attribute extraction calls by not having to specify the
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/// DWARFUnit for each call.
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class DWARFDie {
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  DWARFUnit *U = nullptr;
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  const DWARFDebugInfoEntry *Die = nullptr;
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public:
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  DWARFDie() = default;
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  DWARFDie(DWARFUnit *Unit, const DWARFDebugInfoEntry * D) : U(Unit), Die(D) {}
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  bool isValid() const { return U && Die; }
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  explicit operator bool() const { return isValid(); }
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  const DWARFDebugInfoEntry *getDebugInfoEntry() const { return Die; }
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  DWARFUnit *getDwarfUnit() const { return U; }
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  /// Get the abbreviation declaration for this DIE.
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  ///
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  /// \returns the abbreviation declaration or NULL for null tags.
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  const DWARFAbbreviationDeclaration *getAbbreviationDeclarationPtr() const {
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    assert(isValid() && "must check validity prior to calling");
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    return Die->getAbbreviationDeclarationPtr();
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  }
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  /// Get the absolute offset into the debug info or types section.
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  ///
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  /// \returns the DIE offset or -1U if invalid.
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  uint32_t getOffset() const {
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    assert(isValid() && "must check validity prior to calling");
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    return Die->getOffset();
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  }
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  dwarf::Tag getTag() const {
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    auto AbbrevDecl = getAbbreviationDeclarationPtr();
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    if (AbbrevDecl)
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      return AbbrevDecl->getTag();
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    return dwarf::DW_TAG_null;
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  }
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  bool hasChildren() const {
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    assert(isValid() && "must check validity prior to calling");
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    return Die->hasChildren();
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  }
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  /// Returns true for a valid DIE that terminates a sibling chain.
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  bool isNULL() const {
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    return getAbbreviationDeclarationPtr() == nullptr;
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  }
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  /// Returns true if DIE represents a subprogram (not inlined).
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  bool isSubprogramDIE() const;
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  /// Returns true if DIE represents a subprogram or an inlined subroutine.
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  bool isSubroutineDIE() const;
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  /// Get the parent of this DIE object.
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  ///
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  /// \returns a valid DWARFDie instance if this object has a parent or an
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  /// invalid DWARFDie instance if it doesn't.
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  DWARFDie getParent() const;
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  /// Get the sibling of this DIE object.
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  ///
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  /// \returns a valid DWARFDie instance if this object has a sibling or an
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  /// invalid DWARFDie instance if it doesn't.
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  DWARFDie getSibling() const;
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  /// Get the previous sibling of this DIE object.
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  ///
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  /// \returns a valid DWARFDie instance if this object has a sibling or an
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  /// invalid DWARFDie instance if it doesn't.
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  DWARFDie getPreviousSibling() const;
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  /// Get the first child of this DIE object.
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  ///
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  /// \returns a valid DWARFDie instance if this object has children or an
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  /// invalid DWARFDie instance if it doesn't.
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  DWARFDie getFirstChild() const;
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  /// Get the last child of this DIE object.
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  ///
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  /// \returns a valid null DWARFDie instance if this object has children or an
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  /// invalid DWARFDie instance if it doesn't.
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  DWARFDie getLastChild() const;
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  /// Dump the DIE and all of its attributes to the supplied stream.
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  ///
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  /// \param OS the stream to use for output.
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  /// \param indent the number of characters to indent each line that is output.
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  void dump(raw_ostream &OS, unsigned indent = 0,
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            DIDumpOptions DumpOpts = DIDumpOptions()) const;
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  /// Convenience zero-argument overload for debugging.
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  LLVM_DUMP_METHOD void dump() const;
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  /// Extract the specified attribute from this DIE.
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  ///
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  /// Extract an attribute value from this DIE only. This call doesn't look
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  /// for the attribute value in any DW_AT_specification or
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  /// DW_AT_abstract_origin referenced DIEs.
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  ///
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  /// \param Attr the attribute to extract.
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  /// \returns an optional DWARFFormValue that will have the form value if the
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  /// attribute was successfully extracted.
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  Optional<DWARFFormValue> find(dwarf::Attribute Attr) const;
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  /// Extract the first value of any attribute in Attrs from this DIE.
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  ///
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  /// Extract the first attribute that matches from this DIE only. This call
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  /// doesn't look for the attribute value in any DW_AT_specification or
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  /// DW_AT_abstract_origin referenced DIEs. The attributes will be searched
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  /// linearly in the order they are specified within Attrs.
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  ///
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  /// \param Attrs an array of DWARF attribute to look for.
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  /// \returns an optional that has a valid DWARFFormValue for the first
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  /// matching attribute in Attrs, or None if none of the attributes in Attrs
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  /// exist in this DIE.
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  Optional<DWARFFormValue> find(ArrayRef<dwarf::Attribute> Attrs) const;
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  /// Extract the first value of any attribute in Attrs from this DIE and
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  /// recurse into any DW_AT_specification or DW_AT_abstract_origin referenced
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  /// DIEs.
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  ///
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  /// \param Attrs an array of DWARF attribute to look for.
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  /// \returns an optional that has a valid DWARFFormValue for the first
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  /// matching attribute in Attrs, or None if none of the attributes in Attrs
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  /// exist in this DIE or in any DW_AT_specification or DW_AT_abstract_origin
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  /// DIEs.
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  Optional<DWARFFormValue>
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  findRecursively(ArrayRef<dwarf::Attribute> Attrs) const;
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  /// Extract the specified attribute from this DIE as the referenced DIE.
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  ///
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  /// Regardless of the reference type, return the correct DWARFDie instance if
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  /// the attribute exists. The returned DWARFDie object might be from another
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  /// DWARFUnit, but that is all encapsulated in the new DWARFDie object.
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  ///
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  /// Extract an attribute value from this DIE only. This call doesn't look
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  /// for the attribute value in any DW_AT_specification or
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  /// DW_AT_abstract_origin referenced DIEs.
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  ///
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  /// \param Attr the attribute to extract.
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  /// \returns a valid DWARFDie instance if the attribute exists, or an invalid
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  /// DWARFDie object if it doesn't.
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  DWARFDie getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const;
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  /// Extract the range base attribute from this DIE as absolute section offset.
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  ///
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  /// This is a utility function that checks for either the DW_AT_rnglists_base
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  /// or DW_AT_GNU_ranges_base attribute.
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  ///
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  /// \returns anm optional absolute section offset value for the attribute.
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  Optional<uint64_t> getRangesBaseAttribute() const;
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  /// Get the DW_AT_high_pc attribute value as an address.
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  ///
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  /// In DWARF version 4 and later the high PC can be encoded as an offset from
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  /// the DW_AT_low_pc. This function takes care of extracting the value as an
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  /// address or offset and adds it to the low PC if needed and returns the
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  /// value as an optional in case the DIE doesn't have a DW_AT_high_pc
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  /// attribute.
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  ///
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  /// \param LowPC the low PC that might be needed to calculate the high PC.
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  /// \returns an optional address value for the attribute.
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  Optional<uint64_t> getHighPC(uint64_t LowPC) const;
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  /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU.
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  /// Returns true if both attributes are present.
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  bool getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
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                       uint64_t &SectionIndex) const;
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  /// Get the address ranges for this DIE.
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  ///
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  /// Get the hi/low PC range if both attributes are available or exrtracts the
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  /// non-contiguous address ranges from the DW_AT_ranges attribute.
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  ///
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  /// Extracts the range information from this DIE only. This call doesn't look
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  /// for the range in any DW_AT_specification or DW_AT_abstract_origin DIEs.
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  ///
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  /// \returns a address range vector that might be empty if no address range
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  /// information is available.
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  Expected<DWARFAddressRangesVector> getAddressRanges() const;
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  /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any
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  /// of its children.
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  ///
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  /// Get the hi/low PC range if both attributes are available or exrtracts the
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  /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE
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  /// and all children.
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  ///
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  /// \param Ranges the addres range vector to fill in.
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  void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const;
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  bool addressRangeContainsAddress(const uint64_t Address) const;
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  /// If a DIE represents a subprogram (or inlined subroutine), returns its
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  /// mangled name (or short name, if mangled is missing). This name may be
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  /// fetched from specification or abstract origin for this subprogram.
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  /// Returns null if no name is found.
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  const char *getSubroutineName(DINameKind Kind) const;
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  /// Return the DIE name resolving DW_AT_sepcification or DW_AT_abstract_origin
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  /// references if necessary. Returns null if no name is found.
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  const char *getName(DINameKind Kind) const;
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  /// Returns the declaration line (start line) for a DIE, assuming it specifies
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  /// a subprogram. This may be fetched from specification or abstract origin
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  /// for this subprogram by resolving DW_AT_sepcification or
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  /// DW_AT_abstract_origin references if necessary.
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  uint64_t getDeclLine() const;
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  /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column
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  /// from DIE (or zeroes if they are missing). This function looks for
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  /// DW_AT_call attributes in this DIE only, it will not resolve the attribute
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  /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs.
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  /// \param CallFile filled in with non-zero if successful, zero if there is no
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  /// DW_AT_call_file attribute in this DIE.
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  /// \param CallLine filled in with non-zero if successful, zero if there is no
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  /// DW_AT_call_line attribute in this DIE.
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  /// \param CallColumn filled in with non-zero if successful, zero if there is
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  /// no DW_AT_call_column attribute in this DIE.
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  /// \param CallDiscriminator filled in with non-zero if successful, zero if
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  /// there is no DW_AT_GNU_discriminator attribute in this DIE.
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  void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
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                      uint32_t &CallColumn, uint32_t &CallDiscriminator) const;
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  class attribute_iterator;
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  /// Get an iterator range to all attributes in the current DIE only.
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  ///
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  /// \returns an iterator range for the attributes of the current DIE.
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  iterator_range<attribute_iterator> attributes() const;
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  class iterator;
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  iterator begin() const;
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  iterator end() const;
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  iterator_range<iterator> children() const;
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};
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class DWARFDie::attribute_iterator :
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    public iterator_facade_base<attribute_iterator, std::forward_iterator_tag,
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                                const DWARFAttribute> {
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  /// The DWARF DIE we are extracting attributes from.
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  DWARFDie Die;
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  /// The value vended to clients via the operator*() or operator->().
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  DWARFAttribute AttrValue;
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  /// The attribute index within the abbreviation declaration in Die.
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  uint32_t Index;
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  /// Update the attribute index and attempt to read the attribute value. If the
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  /// attribute is able to be read, update AttrValue and the Index member
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  /// variable. If the attribute value is not able to be read, an appropriate
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  /// error will be set if the Err member variable is non-NULL and the iterator
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  /// will be set to the end value so iteration stops.
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  void updateForIndex(const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I);
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public:
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  attribute_iterator() = delete;
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  explicit attribute_iterator(DWARFDie D, bool End);
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  attribute_iterator &operator++();
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  attribute_iterator &operator--();
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  explicit operator bool() const { return AttrValue.isValid(); }
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  const DWARFAttribute &operator*() const { return AttrValue; }
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  bool operator==(const attribute_iterator &X) const { return Index == X.Index; }
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};
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inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) {
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  return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() &&
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      LHS.getDwarfUnit() == RHS.getDwarfUnit();
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}
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inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) {
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  return !(LHS == RHS);
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}
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inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) {
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  return LHS.getOffset() < RHS.getOffset();
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}
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class DWARFDie::iterator
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    : public iterator_facade_base<iterator, std::bidirectional_iterator_tag,
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                                  const DWARFDie> {
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  DWARFDie Die;
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public:
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  iterator() = default;
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  explicit iterator(DWARFDie D) : Die(D) {
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  }
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  iterator &operator++() {
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    Die = Die.getSibling();
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    return *this;
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  }
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  iterator &operator--() {
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    Die = Die.getPreviousSibling();
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    return *this;
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  }
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  explicit operator bool() const { return Die.isValid(); }
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  const DWARFDie &operator*() const { return Die; }
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  bool operator==(const iterator &X) const { return Die == X.Die; }
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};
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// These inline functions must follow the DWARFDie::iterator definition above
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// as they use functions from that class.
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inline DWARFDie::iterator DWARFDie::begin() const {
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  return iterator(getFirstChild());
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}
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inline DWARFDie::iterator DWARFDie::end() const {
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  return iterator(getLastChild());
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}
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inline iterator_range<DWARFDie::iterator> DWARFDie::children() const {
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  return make_range(begin(), end());
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}
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} // end namespace llvm
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#endif // LLVM_DEBUGINFO_DWARFDIE_H