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 std::string DWARFAbbreviationDeclarationSet::getCodeRange() const {
71   // Create a sorted list of all abbrev codes.
72   std::vector<uint32_t> Codes;
73   Codes.reserve(Decls.size());
74   for (const auto &Decl : Decls)
75     Codes.push_back(Decl.getCode());
76 
77   std::string Buffer;
78   raw_string_ostream Stream(Buffer);
79   // Each iteration through this loop represents a single contiguous range in
80   // the set of codes.
81   for (auto Current = Codes.begin(), End = Codes.end(); Current != End;) {
82     uint32_t RangeStart = *Current;
83     // Add the current range start.
84     Stream << *Current;
85     uint32_t RangeEnd = RangeStart;
86     // Find the end of the current range.
87     while (++Current != End && *Current == RangeEnd + 1)
88       ++RangeEnd;
89     // If there is more than one value in the range, add the range end too.
90     if (RangeStart != RangeEnd)
91       Stream << "-" << RangeEnd;
92     // If there is at least one more range, add a separator.
93     if (Current != End)
94       Stream << ", ";
95   }
96   return Buffer;
97 }
98 
99 DWARFDebugAbbrev::DWARFDebugAbbrev() { clear(); }
100 
101 void DWARFDebugAbbrev::clear() {
102   AbbrDeclSets.clear();
103   PrevAbbrOffsetPos = AbbrDeclSets.end();
104 }
105 
106 void DWARFDebugAbbrev::extract(DataExtractor Data) {
107   clear();
108   this->Data = Data;
109 }
110 
111 void DWARFDebugAbbrev::parse() const {
112   if (!Data)
113     return;
114   uint64_t Offset = 0;
115   auto I = AbbrDeclSets.begin();
116   while (Data->isValidOffset(Offset)) {
117     while (I != AbbrDeclSets.end() && I->first < Offset)
118       ++I;
119     uint64_t CUAbbrOffset = Offset;
120     DWARFAbbreviationDeclarationSet AbbrDecls;
121     if (!AbbrDecls.extract(*Data, &Offset))
122       break;
123     AbbrDeclSets.insert(I, std::make_pair(CUAbbrOffset, std::move(AbbrDecls)));
124   }
125   Data = None;
126 }
127 
128 void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
129   parse();
130 
131   if (AbbrDeclSets.empty()) {
132     OS << "< EMPTY >\n";
133     return;
134   }
135 
136   for (const auto &I : AbbrDeclSets) {
137     OS << format("Abbrev table for offset: 0x%8.8" PRIx64 "\n", I.first);
138     I.second.dump(OS);
139   }
140 }
141 
142 const DWARFAbbreviationDeclarationSet*
143 DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t CUAbbrOffset) const {
144   const auto End = AbbrDeclSets.end();
145   if (PrevAbbrOffsetPos != End && PrevAbbrOffsetPos->first == CUAbbrOffset) {
146     return &(PrevAbbrOffsetPos->second);
147   }
148 
149   const auto Pos = AbbrDeclSets.find(CUAbbrOffset);
150   if (Pos != End) {
151     PrevAbbrOffsetPos = Pos;
152     return &(Pos->second);
153   }
154 
155   if (Data && CUAbbrOffset < Data->getData().size()) {
156     uint64_t Offset = CUAbbrOffset;
157     DWARFAbbreviationDeclarationSet AbbrDecls;
158     if (!AbbrDecls.extract(*Data, &Offset))
159       return nullptr;
160     PrevAbbrOffsetPos =
161         AbbrDeclSets.insert(std::make_pair(CUAbbrOffset, std::move(AbbrDecls)))
162             .first;
163     return &PrevAbbrOffsetPos->second;
164   }
165 
166   return nullptr;
167 }
168