1 //===- DWARFDebugAbbrev.cpp -----------------------------------------------===//
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 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
11 #include "llvm/Support/Format.h"
12 #include "llvm/Support/raw_ostream.h"
13 #include <algorithm>
14 #include <cinttypes>
15 #include <cstdint>
16 
17 using namespace llvm;
18 
19 DWARFAbbreviationDeclarationSet::DWARFAbbreviationDeclarationSet() {
20   clear();
21 }
22 
23 void DWARFAbbreviationDeclarationSet::clear() {
24   Offset = 0;
25   FirstAbbrCode = 0;
26   Decls.clear();
27 }
28 
29 bool DWARFAbbreviationDeclarationSet::extract(DataExtractor Data,
30                                               uint32_t *OffsetPtr) {
31   clear();
32   const uint32_t BeginOffset = *OffsetPtr;
33   Offset = BeginOffset;
34   DWARFAbbreviationDeclaration AbbrDecl;
35   uint32_t PrevAbbrCode = 0;
36   while (AbbrDecl.extract(Data, OffsetPtr)) {
37     if (FirstAbbrCode == 0) {
38       FirstAbbrCode = AbbrDecl.getCode();
39     } else {
40       if (PrevAbbrCode + 1 != AbbrDecl.getCode()) {
41         // Codes are not consecutive, can't do O(1) lookups.
42         FirstAbbrCode = UINT32_MAX;
43       }
44     }
45     PrevAbbrCode = AbbrDecl.getCode();
46     Decls.push_back(std::move(AbbrDecl));
47   }
48   return BeginOffset != *OffsetPtr;
49 }
50 
51 void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
52   for (const auto &Decl : Decls)
53     Decl.dump(OS);
54 }
55 
56 const DWARFAbbreviationDeclaration *
57 DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(
58     uint32_t AbbrCode) const {
59   if (FirstAbbrCode == UINT32_MAX) {
60     for (const auto &Decl : Decls) {
61       if (Decl.getCode() == AbbrCode)
62         return &Decl;
63     }
64     return nullptr;
65   }
66   if (AbbrCode < FirstAbbrCode || AbbrCode >= FirstAbbrCode + Decls.size())
67     return nullptr;
68   return &Decls[AbbrCode - FirstAbbrCode];
69 }
70 
71 DWARFDebugAbbrev::DWARFDebugAbbrev() { clear(); }
72 
73 void DWARFDebugAbbrev::clear() {
74   AbbrDeclSets.clear();
75   PrevAbbrOffsetPos = AbbrDeclSets.end();
76 }
77 
78 void DWARFDebugAbbrev::extract(DataExtractor Data) {
79   clear();
80   this->Data = Data;
81 }
82 
83 void DWARFDebugAbbrev::parse() const {
84   if (!Data)
85     return;
86   uint32_t Offset = 0;
87   DWARFAbbreviationDeclarationSet AbbrDecls;
88   auto I = AbbrDeclSets.begin();
89   while (Data->isValidOffset(Offset)) {
90     while (I != AbbrDeclSets.end() && I->first < Offset)
91       ++I;
92     uint32_t CUAbbrOffset = Offset;
93     if (!AbbrDecls.extract(*Data, &Offset))
94       break;
95     AbbrDeclSets.insert(I, std::make_pair(CUAbbrOffset, std::move(AbbrDecls)));
96   }
97   Data = None;
98 }
99 
100 void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
101   parse();
102 
103   if (AbbrDeclSets.empty()) {
104     OS << "< EMPTY >\n";
105     return;
106   }
107 
108   for (const auto &I : AbbrDeclSets) {
109     OS << format("Abbrev table for offset: 0x%8.8" PRIx64 "\n", I.first);
110     I.second.dump(OS);
111   }
112 }
113 
114 const DWARFAbbreviationDeclarationSet*
115 DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
116   const auto End = AbbrDeclSets.end();
117   if (PrevAbbrOffsetPos != End && PrevAbbrOffsetPos->first == CUAbbrOffset) {
118     return &(PrevAbbrOffsetPos->second);
119   }
120 
121   const auto Pos = AbbrDeclSets.find(CUAbbrOffset);
122   if (Pos != End) {
123     PrevAbbrOffsetPos = Pos;
124     return &(Pos->second);
125   }
126 
127   if (Data && CUAbbrOffset < Data->getData().size()) {
128     uint32_t Offset = CUAbbrOffset;
129     DWARFAbbreviationDeclarationSet AbbrDecls;
130     if (!AbbrDecls.extract(*Data, &Offset))
131       return nullptr;
132     PrevAbbrOffsetPos =
133         AbbrDeclSets.insert(std::make_pair(CUAbbrOffset, std::move(AbbrDecls)))
134             .first;
135     return &PrevAbbrOffsetPos->second;
136   }
137 
138   return nullptr;
139 }
140