LLVM  6.0.0svn
DWARFGdbIndex.cpp
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1 //===- DWARFGdbIndex.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 
11 #include "llvm/ADT/SmallVector.h"
12 #include "llvm/ADT/StringRef.h"
13 #include "llvm/Support/Format.h"
15 #include <algorithm>
16 #include <cassert>
17 #include <cinttypes>
18 #include <cstdint>
19 #include <utility>
20 
21 using namespace llvm;
22 
23 // .gdb_index section format reference:
24 // https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html
25 
26 void DWARFGdbIndex::dumpCUList(raw_ostream &OS) const {
27  OS << format("\n CU list offset = 0x%x, has %" PRId64 " entries:",
28  CuListOffset, (uint64_t)CuList.size())
29  << '\n';
30  uint32_t I = 0;
31  for (const CompUnitEntry &CU : CuList)
32  OS << format(" %d: Offset = 0x%llx, Length = 0x%llx\n", I++, CU.Offset,
33  CU.Length);
34 }
35 
36 void DWARFGdbIndex::dumpAddressArea(raw_ostream &OS) const {
37  OS << format("\n Address area offset = 0x%x, has %" PRId64 " entries:",
38  AddressAreaOffset, (uint64_t)AddressArea.size())
39  << '\n';
40  for (const AddressEntry &Addr : AddressArea)
41  OS << format(
42  " Low/High address = [0x%llx, 0x%llx) (Size: 0x%llx), CU id = %d\n",
43  Addr.LowAddress, Addr.HighAddress, Addr.HighAddress - Addr.LowAddress,
44  Addr.CuIndex);
45 }
46 
47 void DWARFGdbIndex::dumpSymbolTable(raw_ostream &OS) const {
48  OS << format("\n Symbol table offset = 0x%x, size = %" PRId64
49  ", filled slots:",
50  SymbolTableOffset, (uint64_t)SymbolTable.size())
51  << '\n';
52  uint32_t I = -1;
53  for (const SymTableEntry &E : SymbolTable) {
54  ++I;
55  if (!E.NameOffset && !E.VecOffset)
56  continue;
57 
58  OS << format(" %d: Name offset = 0x%x, CU vector offset = 0x%x\n", I,
59  E.NameOffset, E.VecOffset);
60 
61  StringRef Name = ConstantPoolStrings.substr(
62  ConstantPoolOffset - StringPoolOffset + E.NameOffset);
63 
64  auto CuVector = std::find_if(
65  ConstantPoolVectors.begin(), ConstantPoolVectors.end(),
66  [&](const std::pair<uint32_t, SmallVector<uint32_t, 0>> &V) {
67  return V.first == E.VecOffset;
68  });
69  assert(CuVector != ConstantPoolVectors.end() && "Invalid symbol table");
70  uint32_t CuVectorId = CuVector - ConstantPoolVectors.begin();
71  OS << format(" String name: %s, CU vector index: %d\n", Name.data(),
72  CuVectorId);
73  }
74 }
75 
76 void DWARFGdbIndex::dumpConstantPool(raw_ostream &OS) const {
77  OS << format("\n Constant pool offset = 0x%x, has %" PRId64 " CU vectors:",
78  ConstantPoolOffset, (uint64_t)ConstantPoolVectors.size());
79  uint32_t I = 0;
80  for (const auto &V : ConstantPoolVectors) {
81  OS << format("\n %d(0x%x): ", I++, V.first);
82  for (uint32_t Val : V.second)
83  OS << format("0x%x ", Val);
84  }
85  OS << '\n';
86 }
87 
89  if (HasError) {
90  OS << "\n<error parsing>\n";
91  return;
92  }
93 
94  if (HasContent) {
95  OS << " Version = " << Version << '\n';
96  dumpCUList(OS);
97  dumpAddressArea(OS);
98  dumpSymbolTable(OS);
99  dumpConstantPool(OS);
100  }
101 }
102 
103 bool DWARFGdbIndex::parseImpl(DataExtractor Data) {
104  uint32_t Offset = 0;
105 
106  // Only version 7 is supported at this moment.
107  Version = Data.getU32(&Offset);
108  if (Version != 7)
109  return false;
110 
111  CuListOffset = Data.getU32(&Offset);
112  uint32_t CuTypesOffset = Data.getU32(&Offset);
113  AddressAreaOffset = Data.getU32(&Offset);
114  SymbolTableOffset = Data.getU32(&Offset);
115  ConstantPoolOffset = Data.getU32(&Offset);
116 
117  if (Offset != CuListOffset)
118  return false;
119 
120  uint32_t CuListSize = (CuTypesOffset - CuListOffset) / 16;
121  CuList.reserve(CuListSize);
122  for (uint32_t i = 0; i < CuListSize; ++i) {
123  uint64_t CuOffset = Data.getU64(&Offset);
124  uint64_t CuLength = Data.getU64(&Offset);
125  CuList.push_back({CuOffset, CuLength});
126  }
127 
128  // CU Types are no longer needed as DWARF skeleton type units never made it
129  // into the standard.
130  uint32_t CuTypesListSize = (AddressAreaOffset - CuTypesOffset) / 24;
131  if (CuTypesListSize != 0)
132  return false;
133 
134  uint32_t AddressAreaSize = (SymbolTableOffset - AddressAreaOffset) / 20;
135  AddressArea.reserve(AddressAreaSize);
136  for (uint32_t i = 0; i < AddressAreaSize; ++i) {
137  uint64_t LowAddress = Data.getU64(&Offset);
138  uint64_t HighAddress = Data.getU64(&Offset);
139  uint32_t CuIndex = Data.getU32(&Offset);
140  AddressArea.push_back({LowAddress, HighAddress, CuIndex});
141  }
142 
143  // The symbol table. This is an open addressed hash table. The size of the
144  // hash table is always a power of 2.
145  // Each slot in the hash table consists of a pair of offset_type values. The
146  // first value is the offset of the symbol's name in the constant pool. The
147  // second value is the offset of the CU vector in the constant pool.
148  // If both values are 0, then this slot in the hash table is empty. This is ok
149  // because while 0 is a valid constant pool index, it cannot be a valid index
150  // for both a string and a CU vector.
151  uint32_t SymTableSize = (ConstantPoolOffset - SymbolTableOffset) / 8;
152  SymbolTable.reserve(SymTableSize);
153  uint32_t CuVectorsTotal = 0;
154  for (uint32_t i = 0; i < SymTableSize; ++i) {
155  uint32_t NameOffset = Data.getU32(&Offset);
156  uint32_t CuVecOffset = Data.getU32(&Offset);
157  SymbolTable.push_back({NameOffset, CuVecOffset});
158  if (NameOffset || CuVecOffset)
159  ++CuVectorsTotal;
160  }
161 
162  // The constant pool. CU vectors are stored first, followed by strings.
163  // The first value is the number of CU indices in the vector. Each subsequent
164  // value is the index and symbol attributes of a CU in the CU list.
165  for (uint32_t i = 0; i < CuVectorsTotal; ++i) {
166  ConstantPoolVectors.emplace_back(0, SmallVector<uint32_t, 0>());
167  auto &Vec = ConstantPoolVectors.back();
168  Vec.first = Offset - ConstantPoolOffset;
169 
170  uint32_t Num = Data.getU32(&Offset);
171  for (uint32_t j = 0; j < Num; ++j)
172  Vec.second.push_back(Data.getU32(&Offset));
173  }
174 
175  ConstantPoolStrings = Data.getData().drop_front(Offset);
176  StringPoolOffset = Offset;
177  return true;
178 }
179 
181  HasContent = !Data.getData().empty();
182  HasError = HasContent && !parseImpl(Data);
183 }
void push_back(const T &Elt)
Definition: SmallVector.h:212
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
format_object< Ts... > format(const char *Fmt, const Ts &... Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:124
StringRef getData() const
Get the data pointed to by this extractor.
Definition: DataExtractor.h:55
void reserve(size_type N)
Definition: SmallVector.h:380
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:128
uint32_t getU32(uint32_t *offset_ptr) const
Extract a uint32_t value from *offset_ptr.
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:133
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef substr(size_t Start, size_t N=npos) const
Return a reference to the substring from [Start, Start + N).
Definition: StringRef.h:598
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
void dump(raw_ostream &OS)
auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range))
Provide wrappers to std::find_if which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:841
uint64_t getU64(uint32_t *offset_ptr) const
Extract a uint64_t value from *offset_ptr.
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE StringRef drop_front(size_t N=1) const
Return a StringRef equal to &#39;this&#39; but with the first N elements dropped.
Definition: StringRef.h:645
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
void parse(DataExtractor Data)
#define I(x, y, z)
Definition: MD5.cpp:58
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49