GsymReader.cpp revision 360784 
1//===- GsymReader.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/GSYM/GsymReader.h"
10
11#include <assert.h>
12#include <inttypes.h>
13#include <stdio.h>
14#include <stdlib.h>
15
16#include "llvm/DebugInfo/GSYM/GsymCreator.h"
17#include "llvm/DebugInfo/GSYM/InlineInfo.h"
18#include "llvm/DebugInfo/GSYM/LineTable.h"
19#include "llvm/Support/BinaryStreamReader.h"
20#include "llvm/Support/DataExtractor.h"
21#include "llvm/Support/MemoryBuffer.h"
22
23using namespace llvm;
24using namespace gsym;
25
26GsymReader::GsymReader(std::unique_ptr<MemoryBuffer> Buffer) :
27    MemBuffer(std::move(Buffer)),
28    Endian(support::endian::system_endianness()) {}
29
30  GsymReader::GsymReader(GsymReader &&RHS) = default;
31
32GsymReader::~GsymReader() = default;
33
34llvm::Expected<GsymReader> GsymReader::openFile(StringRef Filename) {
35  // Open the input file and return an appropriate error if needed.
36  ErrorOr<std::unique_ptr<MemoryBuffer>> BuffOrErr =
37      MemoryBuffer::getFileOrSTDIN(Filename);
38  auto Err = BuffOrErr.getError();
39  if (Err)
40    return llvm::errorCodeToError(Err);
41  return create(BuffOrErr.get());
42}
43
44llvm::Expected<GsymReader> GsymReader::copyBuffer(StringRef Bytes) {
45  auto MemBuffer = MemoryBuffer::getMemBufferCopy(Bytes, "GSYM bytes");
46  return create(MemBuffer);
47}
48
49llvm::Expected<llvm::gsym::GsymReader>
50GsymReader::create(std::unique_ptr<MemoryBuffer> &MemBuffer) {
51  if (!MemBuffer.get())
52    return createStringError(std::errc::invalid_argument,
53                             "invalid memory buffer");
54  GsymReader GR(std::move(MemBuffer));
55  llvm::Error Err = GR.parse();
56  if (Err)
57    return std::move(Err);
58  return std::move(GR);
59}
60
61llvm::Error
62GsymReader::parse() {
63  BinaryStreamReader FileData(MemBuffer->getBuffer(),
64                              support::endian::system_endianness());
65  // Check for the magic bytes. This file format is designed to be mmap'ed
66  // into a process and accessed as read only. This is done for performance
67  // and efficiency for symbolicating and parsing GSYM data.
68  if (FileData.readObject(Hdr))
69    return createStringError(std::errc::invalid_argument,
70                             "not enough data for a GSYM header");
71
72  const auto HostByteOrder = support::endian::system_endianness();
73  switch (Hdr->Magic) {
74    case GSYM_MAGIC:
75      Endian = HostByteOrder;
76      break;
77    case GSYM_CIGAM:
78      // This is a GSYM file, but not native endianness.
79      Endian = sys::IsBigEndianHost ? support::little : support::big;
80      Swap.reset(new SwappedData);
81      break;
82    default:
83      return createStringError(std::errc::invalid_argument,
84                               "not a GSYM file");
85  }
86
87  bool DataIsLittleEndian = HostByteOrder != support::little;
88  // Read a correctly byte swapped header if we need to.
89  if (Swap) {
90    DataExtractor Data(MemBuffer->getBuffer(), DataIsLittleEndian, 4);
91    if (auto ExpectedHdr = Header::decode(Data))
92      Swap->Hdr = ExpectedHdr.get();
93    else
94      return ExpectedHdr.takeError();
95    Hdr = &Swap->Hdr;
96  }
97
98  // Detect errors in the header and report any that are found. If we make it
99  // past this without errors, we know we have a good magic value, a supported
100  // version number, verified address offset size and a valid UUID size.
101  if (Error Err = Hdr->checkForError())
102    return Err;
103
104  if (!Swap) {
105    // This is the native endianness case that is most common and optimized for
106    // efficient lookups. Here we just grab pointers to the native data and
107    // use ArrayRef objects to allow efficient read only access.
108
109    // Read the address offsets.
110    if (FileData.padToAlignment(Hdr->AddrOffSize) ||
111        FileData.readArray(AddrOffsets,
112                           Hdr->NumAddresses * Hdr->AddrOffSize))
113      return createStringError(std::errc::invalid_argument,
114                              "failed to read address table");
115
116    // Read the address info offsets.
117    if (FileData.padToAlignment(4) ||
118        FileData.readArray(AddrInfoOffsets, Hdr->NumAddresses))
119      return createStringError(std::errc::invalid_argument,
120                              "failed to read address info offsets table");
121
122    // Read the file table.
123    uint32_t NumFiles = 0;
124    if (FileData.readInteger(NumFiles) || FileData.readArray(Files, NumFiles))
125      return createStringError(std::errc::invalid_argument,
126                              "failed to read file table");
127
128    // Get the string table.
129    FileData.setOffset(Hdr->StrtabOffset);
130    if (FileData.readFixedString(StrTab.Data, Hdr->StrtabSize))
131      return createStringError(std::errc::invalid_argument,
132                              "failed to read string table");
133} else {
134  // This is the non native endianness case that is not common and not
135  // optimized for lookups. Here we decode the important tables into local
136  // storage and then set the ArrayRef objects to point to these swapped
137  // copies of the read only data so lookups can be as efficient as possible.
138  DataExtractor Data(MemBuffer->getBuffer(), DataIsLittleEndian, 4);
139
140  // Read the address offsets.
141  uint64_t Offset = alignTo(sizeof(Header), Hdr->AddrOffSize);
142  Swap->AddrOffsets.resize(Hdr->NumAddresses * Hdr->AddrOffSize);
143  switch (Hdr->AddrOffSize) {
144    case 1:
145      if (!Data.getU8(&Offset, Swap->AddrOffsets.data(), Hdr->NumAddresses))
146        return createStringError(std::errc::invalid_argument,
147                                  "failed to read address table");
148      break;
149    case 2:
150      if (!Data.getU16(&Offset,
151                        reinterpret_cast<uint16_t *>(Swap->AddrOffsets.data()),
152                        Hdr->NumAddresses))
153        return createStringError(std::errc::invalid_argument,
154                                  "failed to read address table");
155      break;
156    case 4:
157      if (!Data.getU32(&Offset,
158                        reinterpret_cast<uint32_t *>(Swap->AddrOffsets.data()),
159                        Hdr->NumAddresses))
160        return createStringError(std::errc::invalid_argument,
161                                  "failed to read address table");
162      break;
163    case 8:
164      if (!Data.getU64(&Offset,
165                        reinterpret_cast<uint64_t *>(Swap->AddrOffsets.data()),
166                        Hdr->NumAddresses))
167        return createStringError(std::errc::invalid_argument,
168                                  "failed to read address table");
169    }
170    AddrOffsets = ArrayRef<uint8_t>(Swap->AddrOffsets);
171
172    // Read the address info offsets.
173    Offset = alignTo(Offset, 4);
174    Swap->AddrInfoOffsets.resize(Hdr->NumAddresses);
175    if (Data.getU32(&Offset, Swap->AddrInfoOffsets.data(), Hdr->NumAddresses))
176      AddrInfoOffsets = ArrayRef<uint32_t>(Swap->AddrInfoOffsets);
177    else
178      return createStringError(std::errc::invalid_argument,
179                               "failed to read address table");
180    // Read the file table.
181    const uint32_t NumFiles = Data.getU32(&Offset);
182    if (NumFiles > 0) {
183      Swap->Files.resize(NumFiles);
184      if (Data.getU32(&Offset, &Swap->Files[0].Dir, NumFiles*2))
185        Files = ArrayRef<FileEntry>(Swap->Files);
186      else
187        return createStringError(std::errc::invalid_argument,
188                                 "failed to read file table");
189    }
190    // Get the string table.
191    StrTab.Data = MemBuffer->getBuffer().substr(Hdr->StrtabOffset,
192                                                Hdr->StrtabSize);
193    if (StrTab.Data.empty())
194      return createStringError(std::errc::invalid_argument,
195                               "failed to read string table");
196  }
197  return Error::success();
198
199}
200
201const Header &GsymReader::getHeader() const {
202  // The only way to get a GsymReader is from GsymReader::openFile(...) or
203  // GsymReader::copyBuffer() and the header must be valid and initialized to
204  // a valid pointer value, so the assert below should not trigger.
205  assert(Hdr);
206  return *Hdr;
207}
208
209Optional<uint64_t> GsymReader::getAddress(size_t Index) const {
210  switch (Hdr->AddrOffSize) {
211  case 1: return addressForIndex<uint8_t>(Index);
212  case 2: return addressForIndex<uint16_t>(Index);
213  case 4: return addressForIndex<uint32_t>(Index);
214  case 8: return addressForIndex<uint64_t>(Index);
215  }
216  return llvm::None;
217}
218
219Optional<uint64_t> GsymReader::getAddressInfoOffset(size_t Index) const {
220  const auto NumAddrInfoOffsets = AddrInfoOffsets.size();
221  if (Index < NumAddrInfoOffsets)
222    return AddrInfoOffsets[Index];
223  return llvm::None;
224}
225
226Expected<uint64_t>
227GsymReader::getAddressIndex(const uint64_t Addr) const {
228  if (Addr < Hdr->BaseAddress)
229    return createStringError(std::errc::invalid_argument,
230                             "address 0x%" PRIx64 " not in GSYM", Addr);
231  const uint64_t AddrOffset = Addr - Hdr->BaseAddress;
232  switch (Hdr->AddrOffSize) {
233  case 1: return getAddressOffsetIndex<uint8_t>(AddrOffset);
234  case 2: return getAddressOffsetIndex<uint16_t>(AddrOffset);
235  case 4: return getAddressOffsetIndex<uint32_t>(AddrOffset);
236  case 8: return getAddressOffsetIndex<uint64_t>(AddrOffset);
237  default: break;
238  }
239  return createStringError(std::errc::invalid_argument,
240                           "unsupported address offset size %u",
241                           Hdr->AddrOffSize);
242}
243
244llvm::Expected<FunctionInfo> GsymReader::getFunctionInfo(uint64_t Addr) const {
245  Expected<uint64_t> AddressIndex = getAddressIndex(Addr);
246  if (!AddressIndex)
247    return AddressIndex.takeError();
248  // Address info offsets size should have been checked in parse().
249  assert(*AddressIndex < AddrInfoOffsets.size());
250  auto AddrInfoOffset = AddrInfoOffsets[*AddressIndex];
251  DataExtractor Data(MemBuffer->getBuffer().substr(AddrInfoOffset), Endian, 4);
252  if (Optional<uint64_t> OptAddr = getAddress(*AddressIndex)) {
253    auto ExpectedFI = FunctionInfo::decode(Data, *OptAddr);
254    if (ExpectedFI) {
255      if (ExpectedFI->Range.contains(Addr) || ExpectedFI->Range.size() == 0)
256        return ExpectedFI;
257      return createStringError(std::errc::invalid_argument,
258                                "address 0x%" PRIx64 " not in GSYM", Addr);
259    }
260  }
261  return createStringError(std::errc::invalid_argument,
262                           "failed to extract address[%" PRIu64 "]",
263                           *AddressIndex);
264}
265
266llvm::Expected<LookupResult> GsymReader::lookup(uint64_t Addr) const {
267  Expected<uint64_t> AddressIndex = getAddressIndex(Addr);
268  if (!AddressIndex)
269    return AddressIndex.takeError();
270  // Address info offsets size should have been checked in parse().
271  assert(*AddressIndex < AddrInfoOffsets.size());
272  auto AddrInfoOffset = AddrInfoOffsets[*AddressIndex];
273  DataExtractor Data(MemBuffer->getBuffer().substr(AddrInfoOffset), Endian, 4);
274  if (Optional<uint64_t> OptAddr = getAddress(*AddressIndex))
275    return FunctionInfo::lookup(Data, *this, *OptAddr, Addr);
276  return createStringError(std::errc::invalid_argument,
277                           "failed to extract address[%" PRIu64 "]",
278                           *AddressIndex);
279}
280