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/DebugInfo/DWARF/DWARFAcceleratorTable.h"
11 
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/BinaryFormat/Dwarf.h"
14 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
15 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
16 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
17 #include "llvm/Support/Compiler.h"
18 #include "llvm/Support/Format.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include <cstddef>
21 #include <cstdint>
22 #include <utility>
23 
24 using namespace llvm;
25 
26 bool DWARFAcceleratorTable::extract() {
27   uint32_t Offset = 0;
28 
29   // Check that we can at least read the header.
30   if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength)+4))
31     return false;
32 
33   Hdr.Magic = AccelSection.getU32(&Offset);
34   Hdr.Version = AccelSection.getU16(&Offset);
35   Hdr.HashFunction = AccelSection.getU16(&Offset);
36   Hdr.NumBuckets = AccelSection.getU32(&Offset);
37   Hdr.NumHashes = AccelSection.getU32(&Offset);
38   Hdr.HeaderDataLength = AccelSection.getU32(&Offset);
39 
40   // Check that we can read all the hashes and offsets from the
41   // section (see SourceLevelDebugging.rst for the structure of the index).
42   if (!AccelSection.isValidOffset(sizeof(Hdr) + Hdr.HeaderDataLength +
43                                   Hdr.NumBuckets*4 + Hdr.NumHashes*8))
44     return false;
45 
46   HdrData.DIEOffsetBase = AccelSection.getU32(&Offset);
47   uint32_t NumAtoms = AccelSection.getU32(&Offset);
48 
49   for (unsigned i = 0; i < NumAtoms; ++i) {
50     uint16_t AtomType = AccelSection.getU16(&Offset);
51     auto AtomForm = static_cast<dwarf::Form>(AccelSection.getU16(&Offset));
52     HdrData.Atoms.push_back(std::make_pair(AtomType, AtomForm));
53   }
54 
55   return true;
56 }
57 
58 LLVM_DUMP_METHOD void DWARFAcceleratorTable::dump(raw_ostream &OS) const {
59   // Dump the header.
60   OS << "Magic = " << format("0x%08x", Hdr.Magic) << '\n'
61      << "Version = " << format("0x%04x", Hdr.Version) << '\n'
62      << "Hash function = " << format("0x%08x", Hdr.HashFunction) << '\n'
63      << "Bucket count = " << Hdr.NumBuckets << '\n'
64      << "Hashes count = " << Hdr.NumHashes << '\n'
65      << "HeaderData length = " << Hdr.HeaderDataLength << '\n'
66      << "DIE offset base = " << HdrData.DIEOffsetBase << '\n'
67      << "Number of atoms = " << HdrData.Atoms.size() << '\n';
68 
69   unsigned i = 0;
70   SmallVector<DWARFFormValue, 3> AtomForms;
71   for (const auto &Atom: HdrData.Atoms) {
72     OS << format("Atom[%d] Type: ", i++);
73     auto TypeString = dwarf::AtomTypeString(Atom.first);
74     if (!TypeString.empty())
75       OS << TypeString;
76     else
77       OS << format("DW_ATOM_Unknown_0x%x", Atom.first);
78     OS << " Form: ";
79     auto FormString = dwarf::FormEncodingString(Atom.second);
80     if (!FormString.empty())
81       OS << FormString;
82     else
83       OS << format("DW_FORM_Unknown_0x%x", Atom.second);
84     OS << '\n';
85     AtomForms.push_back(DWARFFormValue(Atom.second));
86   }
87 
88   // Now go through the actual tables and dump them.
89   uint32_t Offset = sizeof(Hdr) + Hdr.HeaderDataLength;
90   unsigned HashesBase = Offset + Hdr.NumBuckets * 4;
91   unsigned OffsetsBase = HashesBase + Hdr.NumHashes * 4;
92 
93   for (unsigned Bucket = 0; Bucket < Hdr.NumBuckets; ++Bucket) {
94     unsigned Index = AccelSection.getU32(&Offset);
95 
96     OS << format("Bucket[%d]\n", Bucket);
97     if (Index == UINT32_MAX) {
98       OS << "  EMPTY\n";
99       continue;
100     }
101 
102     for (unsigned HashIdx = Index; HashIdx < Hdr.NumHashes; ++HashIdx) {
103       unsigned HashOffset = HashesBase + HashIdx*4;
104       unsigned OffsetsOffset = OffsetsBase + HashIdx*4;
105       uint32_t Hash = AccelSection.getU32(&HashOffset);
106 
107       if (Hash % Hdr.NumBuckets != Bucket)
108         break;
109 
110       unsigned DataOffset = AccelSection.getU32(&OffsetsOffset);
111       OS << format("  Hash = 0x%08x Offset = 0x%08x\n", Hash, DataOffset);
112       if (!AccelSection.isValidOffset(DataOffset)) {
113         OS << "    Invalid section offset\n";
114         continue;
115       }
116       while (AccelSection.isValidOffsetForDataOfSize(DataOffset, 4)) {
117         unsigned StringOffset =
118             getRelocatedValue(AccelSection, 4, &DataOffset, &Relocs);
119         if (!StringOffset)
120           break;
121         OS << format("    Name: %08x \"%s\"\n", StringOffset,
122                      StringSection.getCStr(&StringOffset));
123         unsigned NumData = AccelSection.getU32(&DataOffset);
124         for (unsigned Data = 0; Data < NumData; ++Data) {
125           OS << format("    Data[%d] => ", Data);
126           unsigned i = 0;
127           for (auto &Atom : AtomForms) {
128             OS << format("{Atom[%d]: ", i++);
129             if (Atom.extractValue(AccelSection, &DataOffset, nullptr))
130               Atom.dump(OS);
131             else
132               OS << "Error extracting the value";
133             OS << "} ";
134           }
135           OS << '\n';
136         }
137       }
138     }
139   }
140 }
141