LCOV - code coverage report
Current view: top level - include/llvm/DebugInfo/DWARF - DWARFAbbreviationDeclaration.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 8 8 100.0 %
Date: 2018-06-17 00:07:59 Functions: 2 2 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- DWARFAbbreviationDeclaration.h ---------------------------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : 
      10             : #ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
      11             : #define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
      12             : 
      13             : #include "llvm/ADT/Optional.h"
      14             : #include "llvm/ADT/SmallVector.h"
      15             : #include "llvm/ADT/iterator_range.h"
      16             : #include "llvm/BinaryFormat/Dwarf.h"
      17             : #include "llvm/Support/DataExtractor.h"
      18             : #include <cassert>
      19             : #include <cstddef>
      20             : #include <cstdint>
      21             : 
      22             : namespace llvm {
      23             : 
      24             : class DWARFFormValue;
      25             : class DWARFUnit;
      26             : class raw_ostream;
      27             : 
      28      188808 : class DWARFAbbreviationDeclaration {
      29             : public:
      30             :   struct AttributeSpec {
      31             :     AttributeSpec(dwarf::Attribute A, dwarf::Form F, int64_t Value)
      32           6 :         : Attr(A), Form(F), Value(Value) {
      33             :       assert(isImplicitConst());
      34             :     }
      35             :     AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<uint8_t> ByteSize)
      36      131177 :         : Attr(A), Form(F) {
      37             :       assert(!isImplicitConst());
      38      131177 :       this->ByteSize.HasByteSize = ByteSize.hasValue();
      39      131177 :       if (this->ByteSize.HasByteSize)
      40       86289 :         this->ByteSize.ByteSize = *ByteSize;
      41             :     }
      42             : 
      43             :     dwarf::Attribute Attr;
      44             :     dwarf::Form Form;
      45             : 
      46             :   private:
      47             :     /// The following field is used for ByteSize for non-implicit_const
      48             :     /// attributes and as value for implicit_const ones, indicated by
      49             :     /// Form == DW_FORM_implicit_const.
      50             :     /// The following cases are distinguished:
      51             :     /// * Form != DW_FORM_implicit_const and HasByteSize is true:
      52             :     ///     ByteSize contains the fixed size in bytes for the Form in this
      53             :     ///     object.
      54             :     /// * Form != DW_FORM_implicit_const and HasByteSize is false:
      55             :     ///     byte size of Form either varies according to the DWARFUnit
      56             :     ///     that it is contained in or the value size varies and must be
      57             :     ///     decoded from the debug information in order to determine its size.
      58             :     /// * Form == DW_FORM_implicit_const:
      59             :     ///     Value contains value for the implicit_const attribute.
      60             :     struct ByteSizeStorage {
      61             :       bool HasByteSize;
      62             :       uint8_t ByteSize;
      63             :     };
      64             :     union {
      65             :       ByteSizeStorage ByteSize;
      66             :       int64_t Value;
      67             :     };
      68             : 
      69             :   public:
      70             :     bool isImplicitConst() const {
      71             :       return Form == dwarf::DW_FORM_implicit_const;
      72             :     }
      73             : 
      74             :     int64_t getImplicitConstValue() const {
      75             :       assert(isImplicitConst());
      76             :       return Value;
      77             :     }
      78             : 
      79             :     /// Get the fixed byte size of this Form if possible. This function might
      80             :     /// use the DWARFUnit to calculate the size of the Form, like for
      81             :     /// DW_AT_address and DW_AT_ref_addr, so this isn't just an accessor for
      82             :     /// the ByteSize member.
      83             :     Optional<int64_t> getByteSize(const DWARFUnit &U) const;
      84             :   };
      85             :   using AttributeSpecVector = SmallVector<AttributeSpec, 8>;
      86             : 
      87             :   DWARFAbbreviationDeclaration();
      88             : 
      89             :   uint32_t getCode() const { return Code; }
      90             :   uint8_t getCodeByteSize() const { return CodeByteSize; }
      91             :   dwarf::Tag getTag() const { return Tag; }
      92             :   bool hasChildren() const { return HasChildren; }
      93             : 
      94             :   using attr_iterator_range =
      95             :       iterator_range<AttributeSpecVector::const_iterator>;
      96             : 
      97             :   attr_iterator_range attributes() const {
      98             :     return attr_iterator_range(AttributeSpecs.begin(), AttributeSpecs.end());
      99             :   }
     100             : 
     101             :   dwarf::Form getFormByIndex(uint32_t idx) const {
     102             :     assert(idx < AttributeSpecs.size());
     103        7096 :     return AttributeSpecs[idx].Form;
     104             :   }
     105             : 
     106             :   size_t getNumAttributes() const {
     107             :     return AttributeSpecs.size();
     108             :   }
     109             : 
     110             :   dwarf::Attribute getAttrByIndex(uint32_t idx) const {
     111             :     assert(idx < AttributeSpecs.size());
     112        1790 :     return AttributeSpecs[idx].Attr;
     113             :   }
     114             : 
     115             :   /// Get the index of the specified attribute.
     116             :   ///
     117             :   /// Searches the this abbreviation declaration for the index of the specified
     118             :   /// attribute.
     119             :   ///
     120             :   /// \param attr DWARF attribute to search for.
     121             :   /// \returns Optional index of the attribute if found, None otherwise.
     122             :   Optional<uint32_t> findAttributeIndex(dwarf::Attribute attr) const;
     123             : 
     124             :   /// Extract a DWARF form value from a DIE specified by DIE offset.
     125             :   ///
     126             :   /// Extract an attribute value for a DWARFUnit given the DIE offset and the
     127             :   /// attribute.
     128             :   ///
     129             :   /// \param DIEOffset the DIE offset that points to the ULEB128 abbreviation
     130             :   /// code in the .debug_info data.
     131             :   /// \param Attr DWARF attribute to search for.
     132             :   /// \param U the DWARFUnit the contains the DIE.
     133             :   /// \returns Optional DWARF form value if the attribute was extracted.
     134             :   Optional<DWARFFormValue> getAttributeValue(const uint32_t DIEOffset,
     135             :                                              const dwarf::Attribute Attr,
     136             :                                              const DWARFUnit &U) const;
     137             : 
     138             :   bool extract(DataExtractor Data, uint32_t* OffsetPtr);
     139             :   void dump(raw_ostream &OS) const;
     140             : 
     141             :   // Return an optional byte size of all attribute data in this abbreviation
     142             :   // if a constant byte size can be calculated given a DWARFUnit. This allows
     143             :   // DWARF parsing to be faster as many DWARF DIEs have a fixed byte size.
     144             :   Optional<size_t> getFixedAttributesByteSize(const DWARFUnit &U) const;
     145             : 
     146             : private:
     147             :   void clear();
     148             : 
     149             :   /// A helper structure that can quickly determine the size in bytes of an
     150             :   /// abbreviation declaration.
     151             :   struct FixedSizeInfo {
     152             :     /// The fixed byte size for fixed size forms.
     153             :     uint16_t NumBytes = 0;
     154             :     /// Number of DW_FORM_address forms in this abbrevation declaration.
     155             :     uint8_t NumAddrs = 0;
     156             :     /// Number of DW_FORM_ref_addr forms in this abbrevation declaration.
     157             :     uint8_t NumRefAddrs = 0;
     158             :     /// Number of 4 byte in DWARF32 and 8 byte in DWARF64 forms.
     159             :     uint8_t NumDwarfOffsets = 0;
     160             : 
     161             :     FixedSizeInfo() = default;
     162             : 
     163             :     /// Calculate the fixed size in bytes given a DWARFUnit.
     164             :     ///
     165             :     /// \param U the DWARFUnit to use when determing the byte size.
     166             :     /// \returns the size in bytes for all attribute data in this abbreviation.
     167             :     /// The returned size does not include bytes for the  ULEB128 abbreviation
     168             :     /// code
     169             :     size_t getByteSize(const DWARFUnit &U) const;
     170             :   };
     171             : 
     172             :   uint32_t Code;
     173             :   dwarf::Tag Tag;
     174             :   uint8_t CodeByteSize;
     175             :   bool HasChildren;
     176             :   AttributeSpecVector AttributeSpecs;
     177             :   /// If this abbreviation has a fixed byte size then FixedAttributeSize member
     178             :   /// variable below will have a value.
     179             :   Optional<FixedSizeInfo> FixedAttributeSize;
     180             : };
     181             : 
     182             : } // end namespace llvm
     183             : 
     184             : #endif // LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H

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