Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
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//===- DWARFAbbreviationDeclaration.h ---------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
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#define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/SmallVector.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/Support/DataExtractor.h"
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#include <cassert>
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#include <cstddef>
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#include <cstdint>
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namespace llvm {
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class DWARFFormValue;
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class DWARFUnit;
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class raw_ostream;
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class DWARFAbbreviationDeclaration {
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public:
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  struct AttributeSpec {
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    AttributeSpec(dwarf::Attribute A, dwarf::Form F, int64_t Value)
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        : Attr(A), Form(F), Value(Value) {
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      assert(isImplicitConst());
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    }
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    AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<uint8_t> ByteSize)
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        : Attr(A), Form(F) {
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      assert(!isImplicitConst());
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      this->ByteSize.HasByteSize = ByteSize.hasValue();
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      if (this->ByteSize.HasByteSize)
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        this->ByteSize.ByteSize = *ByteSize;
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    }
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    dwarf::Attribute Attr;
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    dwarf::Form Form;
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  private:
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    /// The following field is used for ByteSize for non-implicit_const
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    /// attributes and as value for implicit_const ones, indicated by
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    /// Form == DW_FORM_implicit_const.
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    /// The following cases are distinguished:
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    /// * Form != DW_FORM_implicit_const and HasByteSize is true:
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    ///     ByteSize contains the fixed size in bytes for the Form in this
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    ///     object.
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    /// * Form != DW_FORM_implicit_const and HasByteSize is false:
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    ///     byte size of Form either varies according to the DWARFUnit
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    ///     that it is contained in or the value size varies and must be
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    ///     decoded from the debug information in order to determine its size.
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    /// * Form == DW_FORM_implicit_const:
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    ///     Value contains value for the implicit_const attribute.
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    struct ByteSizeStorage {
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      bool HasByteSize;
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      uint8_t ByteSize;
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    };
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    union {
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      ByteSizeStorage ByteSize;
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      int64_t Value;
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    };
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  public:
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    bool isImplicitConst() const {
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      return Form == dwarf::DW_FORM_implicit_const;
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    }
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    int64_t getImplicitConstValue() const {
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      assert(isImplicitConst());
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      return Value;
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    }
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    /// Get the fixed byte size of this Form if possible. This function might
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    /// use the DWARFUnit to calculate the size of the Form, like for
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    /// DW_AT_address and DW_AT_ref_addr, so this isn't just an accessor for
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    /// the ByteSize member.
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    Optional<int64_t> getByteSize(const DWARFUnit &U) const;
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  };
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  using AttributeSpecVector = SmallVector<AttributeSpec, 8>;
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  DWARFAbbreviationDeclaration();
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  uint32_t getCode() const { return Code; }
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  uint8_t getCodeByteSize() const { return CodeByteSize; }
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  dwarf::Tag getTag() const { return Tag; }
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  bool hasChildren() const { return HasChildren; }
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  using attr_iterator_range =
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      iterator_range<AttributeSpecVector::const_iterator>;
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  attr_iterator_range attributes() const {
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    return attr_iterator_range(AttributeSpecs.begin(), AttributeSpecs.end());
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  }
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  dwarf::Form getFormByIndex(uint32_t idx) const {
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    assert(idx < AttributeSpecs.size());
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    return AttributeSpecs[idx].Form;
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  }
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  size_t getNumAttributes() const {
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    return AttributeSpecs.size();
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  }
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  dwarf::Attribute getAttrByIndex(uint32_t idx) const {
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    assert(idx < AttributeSpecs.size());
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    return AttributeSpecs[idx].Attr;
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  }
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  /// Get the index of the specified attribute.
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  ///
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  /// Searches the this abbreviation declaration for the index of the specified
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  /// attribute.
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  ///
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  /// \param attr DWARF attribute to search for.
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  /// \returns Optional index of the attribute if found, None otherwise.
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  Optional<uint32_t> findAttributeIndex(dwarf::Attribute attr) const;
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  /// Extract a DWARF form value from a DIE specified by DIE offset.
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  ///
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  /// Extract an attribute value for a DWARFUnit given the DIE offset and the
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  /// attribute.
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  ///
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  /// \param DIEOffset the DIE offset that points to the ULEB128 abbreviation
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  /// code in the .debug_info data.
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  /// \param Attr DWARF attribute to search for.
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  /// \param U the DWARFUnit the contains the DIE.
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  /// \returns Optional DWARF form value if the attribute was extracted.
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  Optional<DWARFFormValue> getAttributeValue(const uint32_t DIEOffset,
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                                             const dwarf::Attribute Attr,
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                                             const DWARFUnit &U) const;
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  bool extract(DataExtractor Data, uint32_t* OffsetPtr);
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  void dump(raw_ostream &OS) const;
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  // Return an optional byte size of all attribute data in this abbreviation
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  // if a constant byte size can be calculated given a DWARFUnit. This allows
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  // DWARF parsing to be faster as many DWARF DIEs have a fixed byte size.
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  Optional<size_t> getFixedAttributesByteSize(const DWARFUnit &U) const;
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private:
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  void clear();
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  /// A helper structure that can quickly determine the size in bytes of an
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  /// abbreviation declaration.
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  struct FixedSizeInfo {
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    /// The fixed byte size for fixed size forms.
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    uint16_t NumBytes = 0;
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    /// Number of DW_FORM_address forms in this abbrevation declaration.
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    uint8_t NumAddrs = 0;
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    /// Number of DW_FORM_ref_addr forms in this abbrevation declaration.
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    uint8_t NumRefAddrs = 0;
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    /// Number of 4 byte in DWARF32 and 8 byte in DWARF64 forms.
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    uint8_t NumDwarfOffsets = 0;
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    FixedSizeInfo() = default;
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    /// Calculate the fixed size in bytes given a DWARFUnit.
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    ///
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    /// \param U the DWARFUnit to use when determing the byte size.
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    /// \returns the size in bytes for all attribute data in this abbreviation.
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    /// The returned size does not include bytes for the  ULEB128 abbreviation
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    /// code
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    size_t getByteSize(const DWARFUnit &U) const;
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  };
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  uint32_t Code;
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  dwarf::Tag Tag;
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  uint8_t CodeByteSize;
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  bool HasChildren;
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  AttributeSpecVector AttributeSpecs;
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  /// If this abbreviation has a fixed byte size then FixedAttributeSize member
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  /// variable below will have a value.
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  Optional<FixedSizeInfo> FixedAttributeSize;
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};
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} // end namespace llvm
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#endif // LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H