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 bool 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 (AbbrDecl.extract(Data, OffsetPtr)) {
  36     if (FirstAbbrCode == 0) {
  37       FirstAbbrCode = AbbrDecl.getCode();
  38     } else {
  39       if (PrevAbbrCode + 1 != AbbrDecl.getCode()) {
  40         // Codes are not consecutive, can't do O(1) lookups.
  41         FirstAbbrCode = UINT32_MAX;
  42       }
  43     }
  44     PrevAbbrCode = AbbrDecl.getCode();
  45     Decls.push_back(std::move(AbbrDecl));
  46   }
  47   return BeginOffset != *OffsetPtr;
  48 }
  49
  50 void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
  51   for (const auto &Decl : Decls)
  52     Decl.dump(OS);
  53 }
  54
  55 const DWARFAbbreviationDeclaration *
  56 DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(
  57     uint32_t AbbrCode) const {
  58   if (FirstAbbrCode == UINT32_MAX) {
  59     for (const auto &Decl : Decls) {
  60       if (Decl.getCode() == AbbrCode)
  61         return &Decl;
  62     }
  63     return nullptr;
  64   }
  65   if (AbbrCode < FirstAbbrCode || AbbrCode >= FirstAbbrCode + Decls.size())
  66     return nullptr;
  67   return &Decls[AbbrCode - FirstAbbrCode];
  68 }
  69
  70 DWARFDebugAbbrev::DWARFDebugAbbrev() { clear(); }
  71
  72 void DWARFDebugAbbrev::clear() {
  73   AbbrDeclSets.clear();
  74   PrevAbbrOffsetPos = AbbrDeclSets.end();
  75 }
  76
  77 void DWARFDebugAbbrev::extract(DataExtractor Data) {
  78   clear();
  79   this->Data = Data;
  80 }
  81
  82 void DWARFDebugAbbrev::parse() const {
  83   if (!Data)
  84     return;
  85   uint64_t Offset = 0;
  86   auto I = AbbrDeclSets.begin();
  87   while (Data->isValidOffset(Offset)) {
  88     while (I != AbbrDeclSets.end() && I->first < Offset)
  89       ++I;
  90     uint64_t CUAbbrOffset = Offset;
  91     DWARFAbbreviationDeclarationSet AbbrDecls;
  92     if (!AbbrDecls.extract(*Data, &Offset))
  93       break;
  94     AbbrDeclSets.insert(I, std::make_pair(CUAbbrOffset, std::move(AbbrDecls)));
  95   }
  96   Data = None;
  97 }
  98
  99 void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
 100   parse();
 101
 102   if (AbbrDeclSets.empty()) {
 103     OS << "< EMPTY >\n";
 104     return;
 105   }
 106
 107   for (const auto &I : AbbrDeclSets) {
 108     OS << format("Abbrev table for offset: 0x%8.8" PRIx64 "\n", I.first);
 109     I.second.dump(OS);
 110   }
 111 }
 112
 113 const DWARFAbbreviationDeclarationSet*
 114 DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
 115   const auto End = AbbrDeclSets.end();
 116   if (PrevAbbrOffsetPos != End && PrevAbbrOffsetPos->first == CUAbbrOffset) {
 117     return &(PrevAbbrOffsetPos->second);
 118   }
 119
 120   const auto Pos = AbbrDeclSets.find(CUAbbrOffset);
 121   if (Pos != End) {
 122     PrevAbbrOffsetPos = Pos;
 123     return &(Pos->second);
 124   }
 125
 126   if (Data && CUAbbrOffset < Data->getData().size()) {
 127     uint64_t Offset = CUAbbrOffset;
 128     DWARFAbbreviationDeclarationSet AbbrDecls;
 129     if (!AbbrDecls.extract(*Data, &Offset))
 130       return nullptr;
 131     PrevAbbrOffsetPos =
 132         AbbrDeclSets.insert(std::make_pair(CUAbbrOffset, std::move(AbbrDecls)))
 133             .first;
 134     return &PrevAbbrOffsetPos->second;
 135   }
 136
 137   return nullptr;
 138 }