llvm/lib/DebugInfo/DWARF/DWARFDebugAbbrev.cpp

   1 //===- DWARFDebugAbbrev.cpp -----------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
  10 #include "llvm/Support/Format.h"
  11 #include "llvm/Support/raw_ostream.h"
  12 #include <algorithm>
  13 #include <cinttypes>
  14 #include <cstdint>
  15
  16 using namespace llvm;
  17
  18 DWARFAbbreviationDeclarationSet::DWARFAbbreviationDeclarationSet() {
  19   clear();
  20 }
  21
  22 void DWARFAbbreviationDeclarationSet::clear() {
  23   Offset = 0;
  24   FirstAbbrCode = 0;
  25   Decls.clear();
  26 }
  27
  28 Error DWARFAbbreviationDeclarationSet::extract(DataExtractor Data,
  29                                                uint64_t *OffsetPtr) {
  30   clear();
  31   const uint64_t BeginOffset = *OffsetPtr;
  32   Offset = BeginOffset;
  33   DWARFAbbreviationDeclaration AbbrDecl;
  34   uint32_t PrevAbbrCode = 0;
  35   while (true) {
  36     Expected<DWARFAbbreviationDeclaration::ExtractState> ES =
  37         AbbrDecl.extract(Data, OffsetPtr);
  38     if (!ES)
  39       return ES.takeError();
  40
  41     if (*ES == DWARFAbbreviationDeclaration::ExtractState::Complete)
  42       break;
  43
  44     if (FirstAbbrCode == 0) {
  45       FirstAbbrCode = AbbrDecl.getCode();
  46     } else if (PrevAbbrCode + 1 != AbbrDecl.getCode()) {
  47       // Codes are not consecutive, can't do O(1) lookups.
  48       FirstAbbrCode = UINT32_MAX;
  49     }
  50     PrevAbbrCode = AbbrDecl.getCode();
  51     Decls.push_back(std::move(AbbrDecl));
  52   }
  53   return Error::success();
  54 }
  55
  56 void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
  57   for (const auto &Decl : Decls)
  58     Decl.dump(OS);
  59 }
  60
  61 const DWARFAbbreviationDeclaration *
  62 DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(
  63     uint32_t AbbrCode) const {
  64   if (FirstAbbrCode == UINT32_MAX) {
  65     for (const auto &Decl : Decls) {
  66       if (Decl.getCode() == AbbrCode)
  67         return &Decl;
  68     }
  69     return nullptr;
  70   }
  71   if (AbbrCode < FirstAbbrCode || AbbrCode >= FirstAbbrCode + Decls.size())
  72     return nullptr;
  73   return &Decls[AbbrCode - FirstAbbrCode];
  74 }
  75
  76 std::string DWARFAbbreviationDeclarationSet::getCodeRange() const {
  77   // Create a sorted list of all abbrev codes.
  78   std::vector<uint32_t> Codes;
  79   Codes.reserve(Decls.size());
  80   for (const auto &Decl : Decls)
  81     Codes.push_back(Decl.getCode());
  82
  83   std::string Buffer;
  84   raw_string_ostream Stream(Buffer);
  85   // Each iteration through this loop represents a single contiguous range in
  86   // the set of codes.
  87   for (auto Current = Codes.begin(), End = Codes.end(); Current != End;) {
  88     uint32_t RangeStart = *Current;
  89     // Add the current range start.
  90     Stream << *Current;
  91     uint32_t RangeEnd = RangeStart;
  92     // Find the end of the current range.
  93     while (++Current != End && *Current == RangeEnd + 1)
  94       ++RangeEnd;
  95     // If there is more than one value in the range, add the range end too.
  96     if (RangeStart != RangeEnd)
  97       Stream << "-" << RangeEnd;
  98     // If there is at least one more range, add a separator.
  99     if (Current != End)
 100       Stream << ", ";
 101   }
 102   return Buffer;
 103 }
 104
 105 DWARFDebugAbbrev::DWARFDebugAbbrev(DataExtractor Data)
 106     : AbbrDeclSets(), PrevAbbrOffsetPos(AbbrDeclSets.end()), Data(Data) {}
 107
 108 Error DWARFDebugAbbrev::parse() const {
 109   if (!Data)
 110     return Error::success();
 111   uint64_t Offset = 0;
 112   auto I = AbbrDeclSets.begin();
 113   while (Data->isValidOffset(Offset)) {
 114     while (I != AbbrDeclSets.end() && I->first < Offset)
 115       ++I;
 116     uint64_t CUAbbrOffset = Offset;
 117     DWARFAbbreviationDeclarationSet AbbrDecls;
 118     if (Error Err = AbbrDecls.extract(*Data, &Offset)) {
 119       Data = std::nullopt;
 120       return Err;
 121     }
 122     AbbrDeclSets.insert(I, std::make_pair(CUAbbrOffset, std::move(AbbrDecls)));
 123   }
 124   Data = std::nullopt;
 125   return Error::success();
 126 }
 127
 128 void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
 129   if (Error Err = parse())
 130     // FIXME: We should propagate this error or otherwise display it.
 131     llvm::consumeError(std::move(Err));
 132
 133   if (AbbrDeclSets.empty()) {
 134     OS << "< EMPTY >\n";
 135     return;
 136   }
 137
 138   for (const auto &I : AbbrDeclSets) {
 139     OS << format("Abbrev table for offset: 0x%8.8" PRIx64 "\n", I.first);
 140     I.second.dump(OS);
 141   }
 142 }
 143
 144 Expected<const DWARFAbbreviationDeclarationSet *>
 145 DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
 146   const auto End = AbbrDeclSets.end();
 147   if (PrevAbbrOffsetPos != End && PrevAbbrOffsetPos->first == CUAbbrOffset) {
 148     return &PrevAbbrOffsetPos->second;
 149   }
 150
 151   const auto Pos = AbbrDeclSets.find(CUAbbrOffset);
 152   if (Pos != End) {
 153     PrevAbbrOffsetPos = Pos;
 154     return &Pos->second;
 155   }
 156
 157   if (!Data || CUAbbrOffset >= Data->getData().size())
 158     return make_error<llvm::object::GenericBinaryError>(
 159         "the abbreviation offset into the .debug_abbrev section is not valid");
 160
 161   uint64_t Offset = CUAbbrOffset;
 162   DWARFAbbreviationDeclarationSet AbbrDecls;
 163   if (Error Err = AbbrDecls.extract(*Data, &Offset))
 164     return std::move(Err);
 165
 166   PrevAbbrOffsetPos =
 167       AbbrDeclSets.insert(std::make_pair(CUAbbrOffset, std::move(AbbrDecls)))
 168           .first;
 169   return &PrevAbbrOffsetPos->second;
 170 }