1 //===- DWARFAcceleratorTable.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/ADT/SmallVector.h"
11 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
12 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
13 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
14 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
15 #include "llvm/Support/Dwarf.h"
16 #include "llvm/Support/Compiler.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/raw_ostream.h"
19 #include <cstddef>
20 #include <cstdint>
21 #include <utility>
22 
23 using namespace llvm;
24 
25 bool DWARFAcceleratorTable::extract() {
26   uint32_t Offset = 0;
27 
28   // Check that we can at least read the header.
29   if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength)+4))
30     return false;
31 
32   Hdr.Magic = AccelSection.getU32(&Offset);
33   Hdr.Version = AccelSection.getU16(&Offset);
34   Hdr.HashFunction = AccelSection.getU16(&Offset);
35   Hdr.NumBuckets = AccelSection.getU32(&Offset);
36   Hdr.NumHashes = AccelSection.getU32(&Offset);
37   Hdr.HeaderDataLength = AccelSection.getU32(&Offset);
38 
39   // Check that we can read all the hashes and offsets from the
40   // section (see SourceLevelDebugging.rst for the structure of the index).
41   if (!AccelSection.isValidOffset(sizeof(Hdr) + Hdr.HeaderDataLength +
42                                   Hdr.NumBuckets*4 + Hdr.NumHashes*8))
43     return false;
44 
45   HdrData.DIEOffsetBase = AccelSection.getU32(&Offset);
46   uint32_t NumAtoms = AccelSection.getU32(&Offset);
47 
48   for (unsigned i = 0; i < NumAtoms; ++i) {
49     uint16_t AtomType = AccelSection.getU16(&Offset);
50     auto AtomForm = static_cast<dwarf::Form>(AccelSection.getU16(&Offset));
51     HdrData.Atoms.push_back(std::make_pair(AtomType, AtomForm));
52   }
53 
54   return true;
55 }
56 
57 LLVM_DUMP_METHOD void DWARFAcceleratorTable::dump(raw_ostream &OS) const {
58   // Dump the header.
59   OS << "Magic = " << format("0x%08x", Hdr.Magic) << '\n'
60      << "Version = " << format("0x%04x", Hdr.Version) << '\n'
61      << "Hash function = " << format("0x%08x", Hdr.HashFunction) << '\n'
62      << "Bucket count = " << Hdr.NumBuckets << '\n'
63      << "Hashes count = " << Hdr.NumHashes << '\n'
64      << "HeaderData length = " << Hdr.HeaderDataLength << '\n'
65      << "DIE offset base = " << HdrData.DIEOffsetBase << '\n'
66      << "Number of atoms = " << HdrData.Atoms.size() << '\n';
67 
68   unsigned i = 0;
69   SmallVector<DWARFFormValue, 3> AtomForms;
70   for (const auto &Atom: HdrData.Atoms) {
71     OS << format("Atom[%d] Type: ", i++);
72     auto TypeString = dwarf::AtomTypeString(Atom.first);
73     if (!TypeString.empty())
74       OS << TypeString;
75     else
76       OS << format("DW_ATOM_Unknown_0x%x", Atom.first);
77     OS << " Form: ";
78     auto FormString = dwarf::FormEncodingString(Atom.second);
79     if (!FormString.empty())
80       OS << FormString;
81     else
82       OS << format("DW_FORM_Unknown_0x%x", Atom.second);
83     OS << '\n';
84     AtomForms.push_back(DWARFFormValue(Atom.second));
85   }
86 
87   // Now go through the actual tables and dump them.
88   uint32_t Offset = sizeof(Hdr) + Hdr.HeaderDataLength;
89   unsigned HashesBase = Offset + Hdr.NumBuckets * 4;
90   unsigned OffsetsBase = HashesBase + Hdr.NumHashes * 4;
91 
92   for (unsigned Bucket = 0; Bucket < Hdr.NumBuckets; ++Bucket) {
93     unsigned Index = AccelSection.getU32(&Offset);
94 
95     OS << format("Bucket[%d]\n", Bucket);
96     if (Index == UINT32_MAX) {
97       OS << "  EMPTY\n";
98       continue;
99     }
100 
101     for (unsigned HashIdx = Index; HashIdx < Hdr.NumHashes; ++HashIdx) {
102       unsigned HashOffset = HashesBase + HashIdx*4;
103       unsigned OffsetsOffset = OffsetsBase + HashIdx*4;
104       uint32_t Hash = AccelSection.getU32(&HashOffset);
105 
106       if (Hash % Hdr.NumBuckets != Bucket)
107         break;
108 
109       unsigned DataOffset = AccelSection.getU32(&OffsetsOffset);
110       OS << format("  Hash = 0x%08x Offset = 0x%08x\n", Hash, DataOffset);
111       if (!AccelSection.isValidOffset(DataOffset)) {
112         OS << "    Invalid section offset\n";
113         continue;
114       }
115       while (AccelSection.isValidOffsetForDataOfSize(DataOffset, 4)) {
116         unsigned StringOffset =
117             getRelocatedValue(AccelSection, 4, &DataOffset, &Relocs);
118         if (!StringOffset)
119           break;
120         OS << format("    Name: %08x \"%s\"\n", StringOffset,
121                      StringSection.getCStr(&StringOffset));
122         unsigned NumData = AccelSection.getU32(&DataOffset);
123         for (unsigned Data = 0; Data < NumData; ++Data) {
124           OS << format("    Data[%d] => ", Data);
125           unsigned i = 0;
126           for (auto &Atom : AtomForms) {
127             OS << format("{Atom[%d]: ", i++);
128             if (Atom.extractValue(AccelSection, &DataOffset, nullptr))
129               Atom.dump(OS);
130             else
131               OS << "Error extracting the value";
132             OS << "} ";
133           }
134           OS << '\n';
135         }
136       }
137     }
138   }
139 }
140