aboutsummaryrefslogtreecommitdiffstats
path: root/COFF/DebugTypes.cpp
blob: 78c1c78b408d15ec0758f95d21749b98c816726d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
//===- DebugTypes.cpp -----------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "DebugTypes.h"
#include "Driver.h"
#include "InputFiles.h"
#include "lld/Common/ErrorHandler.h"
#include "llvm/DebugInfo/CodeView/TypeRecord.h"
#include "llvm/DebugInfo/PDB/GenericError.h"
#include "llvm/DebugInfo/PDB/Native/InfoStream.h"
#include "llvm/DebugInfo/PDB/Native/NativeSession.h"
#include "llvm/DebugInfo/PDB/Native/PDBFile.h"
#include "llvm/Support/Path.h"

using namespace lld;
using namespace lld::coff;
using namespace llvm;
using namespace llvm::codeview;

namespace {
// The TypeServerSource class represents a PDB type server, a file referenced by
// OBJ files compiled with MSVC /Zi. A single PDB can be shared by several OBJ
// files, therefore there must be only once instance per OBJ lot. The file path
// is discovered from the dependent OBJ's debug type stream. The
// TypeServerSource object is then queued and loaded by the COFF Driver. The
// debug type stream for such PDB files will be merged first in the final PDB,
// before any dependent OBJ.
class TypeServerSource : public TpiSource {
public:
  explicit TypeServerSource(MemoryBufferRef m, llvm::pdb::NativeSession *s)
      : TpiSource(PDB, nullptr), session(s), mb(m) {}

  // Queue a PDB type server for loading in the COFF Driver
  static void enqueue(const ObjFile *dependentFile,
                      const TypeServer2Record &ts);

  // Create an instance
  static Expected<TypeServerSource *> getInstance(MemoryBufferRef m);

  // Fetch the PDB instance loaded for a corresponding dependent OBJ.
  static Expected<TypeServerSource *>
  findFromFile(const ObjFile *dependentFile);

  static std::map<std::string, std::pair<std::string, TypeServerSource *>>
      instances;

  // The interface to the PDB (if it was opened successfully)
  std::unique_ptr<llvm::pdb::NativeSession> session;

private:
  MemoryBufferRef mb;
};

// This class represents the debug type stream of an OBJ file that depends on a
// PDB type server (see TypeServerSource).
class UseTypeServerSource : public TpiSource {
public:
  UseTypeServerSource(const ObjFile *f, const TypeServer2Record *ts)
      : TpiSource(UsingPDB, f), typeServerDependency(*ts) {}

  // Information about the PDB type server dependency, that needs to be loaded
  // in before merging this OBJ.
  TypeServer2Record typeServerDependency;
};

// This class represents the debug type stream of a Microsoft precompiled
// headers OBJ (PCH OBJ). This OBJ kind needs to be merged first in the output
// PDB, before any other OBJs that depend on this. Note that only MSVC generate
// such files, clang does not.
class PrecompSource : public TpiSource {
public:
  PrecompSource(const ObjFile *f) : TpiSource(PCH, f) {}
};

// This class represents the debug type stream of an OBJ file that depends on a
// Microsoft precompiled headers OBJ (see PrecompSource).
class UsePrecompSource : public TpiSource {
public:
  UsePrecompSource(const ObjFile *f, const PrecompRecord *precomp)
      : TpiSource(UsingPCH, f), precompDependency(*precomp) {}

  // Information about the Precomp OBJ dependency, that needs to be loaded in
  // before merging this OBJ.
  PrecompRecord precompDependency;
};
} // namespace

static std::vector<std::unique_ptr<TpiSource>> GC;

TpiSource::TpiSource(TpiKind k, const ObjFile *f) : kind(k), file(f) {
  GC.push_back(std::unique_ptr<TpiSource>(this));
}

TpiSource *lld::coff::makeTpiSource(const ObjFile *f) {
  return new TpiSource(TpiSource::Regular, f);
}

TpiSource *lld::coff::makeUseTypeServerSource(const ObjFile *f,
                                              const TypeServer2Record *ts) {
  TypeServerSource::enqueue(f, *ts);
  return new UseTypeServerSource(f, ts);
}

TpiSource *lld::coff::makePrecompSource(const ObjFile *f) {
  return new PrecompSource(f);
}

TpiSource *lld::coff::makeUsePrecompSource(const ObjFile *f,
                                           const PrecompRecord *precomp) {
  return new UsePrecompSource(f, precomp);
}

namespace lld {
namespace coff {
template <>
const PrecompRecord &retrieveDependencyInfo(const TpiSource *source) {
  assert(source->kind == TpiSource::UsingPCH);
  return ((const UsePrecompSource *)source)->precompDependency;
}

template <>
const TypeServer2Record &retrieveDependencyInfo(const TpiSource *source) {
  assert(source->kind == TpiSource::UsingPDB);
  return ((const UseTypeServerSource *)source)->typeServerDependency;
}
} // namespace coff
} // namespace lld

std::map<std::string, std::pair<std::string, TypeServerSource *>>
    TypeServerSource::instances;

// Make a PDB path assuming the PDB is in the same folder as the OBJ
static std::string getPdbBaseName(const ObjFile *file, StringRef tSPath) {
  StringRef localPath =
      !file->parentName.empty() ? file->parentName : file->getName();
  SmallString<128> path = sys::path::parent_path(localPath);

  // Currently, type server PDBs are only created by MSVC cl, which only runs
  // on Windows, so we can assume type server paths are Windows style.
  sys::path::append(path, sys::path::filename(tSPath, sys::path::Style::windows));
  return path.str();
}

// The casing of the PDB path stamped in the OBJ can differ from the actual path
// on disk. With this, we ensure to always use lowercase as a key for the
// PDBInputFile::Instances map, at least on Windows.
static std::string normalizePdbPath(StringRef path) {
#if defined(_WIN32)
  return path.lower();
#else // LINUX
  return path;
#endif
}

// If existing, return the actual PDB path on disk.
static Optional<std::string> findPdbPath(StringRef pdbPath,
                                         const ObjFile *dependentFile) {
  // Ensure the file exists before anything else. In some cases, if the path
  // points to a removable device, Driver::enqueuePath() would fail with an
  // error (EAGAIN, "resource unavailable try again") which we want to skip
  // silently.
  if (llvm::sys::fs::exists(pdbPath))
    return normalizePdbPath(pdbPath);
  std::string ret = getPdbBaseName(dependentFile, pdbPath);
  if (llvm::sys::fs::exists(ret))
    return normalizePdbPath(ret);
  return None;
}

// Fetch the PDB instance that was already loaded by the COFF Driver.
Expected<TypeServerSource *>
TypeServerSource::findFromFile(const ObjFile *dependentFile) {
  const TypeServer2Record &ts =
      retrieveDependencyInfo<TypeServer2Record>(dependentFile->debugTypesObj);

  Optional<std::string> p = findPdbPath(ts.Name, dependentFile);
  if (!p)
    return createFileError(ts.Name, errorCodeToError(std::error_code(
                                        ENOENT, std::generic_category())));

  auto it = TypeServerSource::instances.find(*p);
  // The PDB file exists on disk, at this point we expect it to have been
  // inserted in the map by TypeServerSource::loadPDB()
  assert(it != TypeServerSource::instances.end());

  std::pair<std::string, TypeServerSource *> &pdb = it->second;

  if (!pdb.second)
    return createFileError(
        *p, createStringError(inconvertibleErrorCode(), pdb.first.c_str()));

  pdb::PDBFile &pdbFile = (pdb.second)->session->getPDBFile();
  pdb::InfoStream &info = cantFail(pdbFile.getPDBInfoStream());

  // Just because a file with a matching name was found doesn't mean it can be
  // used. The GUID must match between the PDB header and the OBJ
  // TypeServer2 record. The 'Age' is used by MSVC incremental compilation.
  if (info.getGuid() != ts.getGuid())
    return createFileError(
        ts.Name,
        make_error<pdb::PDBError>(pdb::pdb_error_code::signature_out_of_date));

  return pdb.second;
}

// FIXME: Temporary interface until PDBLinker::maybeMergeTypeServerPDB() is
// moved here.
Expected<llvm::pdb::NativeSession *>
lld::coff::findTypeServerSource(const ObjFile *f) {
  Expected<TypeServerSource *> ts = TypeServerSource::findFromFile(f);
  if (!ts)
    return ts.takeError();
  return ts.get()->session.get();
}

// Queue a PDB type server for loading in the COFF Driver
void TypeServerSource::enqueue(const ObjFile *dependentFile,
                               const TypeServer2Record &ts) {
  // Start by finding where the PDB is located (either the record path or next
  // to the OBJ file)
  Optional<std::string> p = findPdbPath(ts.Name, dependentFile);
  if (!p)
    return;
  auto it = TypeServerSource::instances.emplace(
      *p, std::pair<std::string, TypeServerSource *>{});
  if (!it.second)
    return; // another OBJ already scheduled this PDB for load

  driver->enqueuePath(*p, false);
}

// Create an instance of TypeServerSource or an error string if the PDB couldn't
// be loaded. The error message will be displayed later, when the referring OBJ
// will be merged in. NOTE - a PDB load failure is not a link error: some
// debug info will simply be missing from the final PDB - that is the default
// accepted behavior.
void lld::coff::loadTypeServerSource(llvm::MemoryBufferRef m) {
  std::string path = normalizePdbPath(m.getBufferIdentifier());

  Expected<TypeServerSource *> ts = TypeServerSource::getInstance(m);
  if (!ts)
    TypeServerSource::instances[path] = {toString(ts.takeError()), nullptr};
  else
    TypeServerSource::instances[path] = {{}, *ts};
}

Expected<TypeServerSource *> TypeServerSource::getInstance(MemoryBufferRef m) {
  std::unique_ptr<llvm::pdb::IPDBSession> iSession;
  Error err = pdb::NativeSession::createFromPdb(
      MemoryBuffer::getMemBuffer(m, false), iSession);
  if (err)
    return std::move(err);

  std::unique_ptr<llvm::pdb::NativeSession> session(
      static_cast<pdb::NativeSession *>(iSession.release()));

  pdb::PDBFile &pdbFile = session->getPDBFile();
  Expected<pdb::InfoStream &> info = pdbFile.getPDBInfoStream();
  // All PDB Files should have an Info stream.
  if (!info)
    return info.takeError();
  return new TypeServerSource(m, session.release());
}