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