Bug Summary

File:src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/include/clang/Basic/DirectoryEntry.h
Warning:line 47, column 55
Called C++ object pointer is null

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name FileManager.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangBasic/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/lib/Basic -I /usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/lib/Basic/Targets -I /usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangBasic/../include -I /usr/src/gnu/usr.bin/clang/libclangBasic/obj -I /usr/src/gnu/usr.bin/clang/libclangBasic/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangBasic/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/lib/Basic/FileManager.cpp

/usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/lib/Basic/FileManager.cpp

→
1//===--- FileManager.cpp - File System Probing and Caching ----------------===//
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// This file implements the FileManager interface.
10//
11//===----------------------------------------------------------------------===//
12//
13// TODO: This should index all interesting directories with dirent calls.
14// getdirentries ?
15// opendir/readdir_r/closedir ?
16//
17//===----------------------------------------------------------------------===//
18
19#include "clang/Basic/FileManager.h"
20#include "clang/Basic/FileSystemStatCache.h"
21#include "llvm/ADT/STLExtras.h"
22#include "llvm/ADT/SmallString.h"
23#include "llvm/ADT/Statistic.h"
24#include "llvm/Config/llvm-config.h"
25#include "llvm/Support/FileSystem.h"
26#include "llvm/Support/MemoryBuffer.h"
27#include "llvm/Support/Path.h"
28#include "llvm/Support/raw_ostream.h"
29#include <algorithm>
30#include <cassert>
31#include <climits>
32#include <cstdint>
33#include <cstdlib>
34#include <string>
35#include <utility>
36
37using namespace clang;
38
39#define DEBUG_TYPE"file-search" "file-search"
40
41ALWAYS_ENABLED_STATISTIC(NumDirLookups, "Number of directory lookups.")static llvm::TrackingStatistic NumDirLookups = {"file-search"
, "NumDirLookups", "Number of directory lookups."};
42ALWAYS_ENABLED_STATISTIC(NumFileLookups, "Number of file lookups.")static llvm::TrackingStatistic NumFileLookups = {"file-search"
, "NumFileLookups", "Number of file lookups."};
43ALWAYS_ENABLED_STATISTIC(NumDirCacheMisses,static llvm::TrackingStatistic NumDirCacheMisses = {"file-search"
, "NumDirCacheMisses", "Number of directory cache misses."}
44 "Number of directory cache misses.")static llvm::TrackingStatistic NumDirCacheMisses = {"file-search"
, "NumDirCacheMisses", "Number of directory cache misses."};
45ALWAYS_ENABLED_STATISTIC(NumFileCacheMisses, "Number of file cache misses.")static llvm::TrackingStatistic NumFileCacheMisses = {"file-search"
, "NumFileCacheMisses", "Number of file cache misses."};
46
47//===----------------------------------------------------------------------===//
48// Common logic.
49//===----------------------------------------------------------------------===//
50
51FileManager::FileManager(const FileSystemOptions &FSO,
52 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS)
53 : FS(std::move(FS)), FileSystemOpts(FSO), SeenDirEntries(64),
54 SeenFileEntries(64), NextFileUID(0) {
55 // If the caller doesn't provide a virtual file system, just grab the real
56 // file system.
57 if (!this->FS)
58 this->FS = llvm::vfs::getRealFileSystem();
59}
60
61FileManager::~FileManager() = default;
62
63void FileManager::setStatCache(std::unique_ptr<FileSystemStatCache> statCache) {
64 assert(statCache && "No stat cache provided?")((void)0);
65 StatCache = std::move(statCache);
66}
67
68void FileManager::clearStatCache() { StatCache.reset(); }
69
70/// Retrieve the directory that the given file name resides in.
71/// Filename can point to either a real file or a virtual file.
72static llvm::Expected<DirectoryEntryRef>
73getDirectoryFromFile(FileManager &FileMgr, StringRef Filename,
74 bool CacheFailure) {
75 if (Filename.empty())
76 return llvm::errorCodeToError(
77 make_error_code(std::errc::no_such_file_or_directory));
78
79 if (llvm::sys::path::is_separator(Filename[Filename.size() - 1]))
80 return llvm::errorCodeToError(make_error_code(std::errc::is_a_directory));
81
82 StringRef DirName = llvm::sys::path::parent_path(Filename);
83 // Use the current directory if file has no path component.
84 if (DirName.empty())
85 DirName = ".";
86
87 return FileMgr.getDirectoryRef(DirName, CacheFailure);
88}
89
90/// Add all ancestors of the given path (pointing to either a file or
91/// a directory) as virtual directories.
92void FileManager::addAncestorsAsVirtualDirs(StringRef Path) {
93 StringRef DirName = llvm::sys::path::parent_path(Path);
94 if (DirName.empty())
95 DirName = ".";
96
97 auto &NamedDirEnt = *SeenDirEntries.insert(
98 {DirName, std::errc::no_such_file_or_directory}).first;
99
100 // When caching a virtual directory, we always cache its ancestors
101 // at the same time. Therefore, if DirName is already in the cache,
102 // we don't need to recurse as its ancestors must also already be in
103 // the cache (or it's a known non-virtual directory).
104 if (NamedDirEnt.second)
105 return;
106
107 // Add the virtual directory to the cache.
108 auto UDE = std::make_unique<DirectoryEntry>();
109 UDE->Name = NamedDirEnt.first();
110 NamedDirEnt.second = *UDE.get();
111 VirtualDirectoryEntries.push_back(std::move(UDE));
112
113 // Recursively add the other ancestors.
114 addAncestorsAsVirtualDirs(DirName);
115}
116
117llvm::Expected<DirectoryEntryRef>
118FileManager::getDirectoryRef(StringRef DirName, bool CacheFailure) {
119 // stat doesn't like trailing separators except for root directory.
120 // At least, on Win32 MSVCRT, stat() cannot strip trailing '/'.
121 // (though it can strip '\\')
122 if (DirName.size() > 1 &&
123 DirName != llvm::sys::path::root_path(DirName) &&
124 llvm::sys::path::is_separator(DirName.back()))
125 DirName = DirName.substr(0, DirName.size()-1);
126#ifdef _WIN32
127 // Fixing a problem with "clang C:test.c" on Windows.
128 // Stat("C:") does not recognize "C:" as a valid directory
129 std::string DirNameStr;
130 if (DirName.size() > 1 && DirName.back() == ':' &&
131 DirName.equals_insensitive(llvm::sys::path::root_name(DirName))) {
132 DirNameStr = DirName.str() + '.';
133 DirName = DirNameStr;
134 }
135#endif
136
137 ++NumDirLookups;
138
139 // See if there was already an entry in the map. Note that the map
140 // contains both virtual and real directories.
141 auto SeenDirInsertResult =
142 SeenDirEntries.insert({DirName, std::errc::no_such_file_or_directory});
143 if (!SeenDirInsertResult.second) {
144 if (SeenDirInsertResult.first->second)
145 return DirectoryEntryRef(*SeenDirInsertResult.first);
146 return llvm::errorCodeToError(SeenDirInsertResult.first->second.getError());
147 }
148
149 // We've not seen this before. Fill it in.
150 ++NumDirCacheMisses;
151 auto &NamedDirEnt = *SeenDirInsertResult.first;
152 assert(!NamedDirEnt.second && "should be newly-created")((void)0);
153
154 // Get the null-terminated directory name as stored as the key of the
155 // SeenDirEntries map.
156 StringRef InterndDirName = NamedDirEnt.first();
157
158 // Check to see if the directory exists.
159 llvm::vfs::Status Status;
160 auto statError = getStatValue(InterndDirName, Status, false,
161 nullptr /*directory lookup*/);
162 if (statError) {
163 // There's no real directory at the given path.
164 if (CacheFailure)
165 NamedDirEnt.second = statError;
166 else
167 SeenDirEntries.erase(DirName);
168 return llvm::errorCodeToError(statError);
169 }
170
171 // It exists. See if we have already opened a directory with the
172 // same inode (this occurs on Unix-like systems when one dir is
173 // symlinked to another, for example) or the same path (on
174 // Windows).
175 DirectoryEntry &UDE = UniqueRealDirs[Status.getUniqueID()];
176
177 NamedDirEnt.second = UDE;
178 if (UDE.getName().empty()) {
179 // We don't have this directory yet, add it. We use the string
180 // key from the SeenDirEntries map as the string.
181 UDE.Name = InterndDirName;
182 }
183
184 return DirectoryEntryRef(NamedDirEnt);
185}
186
187llvm::ErrorOr<const DirectoryEntry *>
188FileManager::getDirectory(StringRef DirName, bool CacheFailure) {
189 auto Result = getDirectoryRef(DirName, CacheFailure);
190 if (Result)
191 return &Result->getDirEntry();
192 return llvm::errorToErrorCode(Result.takeError());
193}
194
195llvm::ErrorOr<const FileEntry *>
196FileManager::getFile(StringRef Filename, bool openFile, bool CacheFailure) {
197 auto Result = getFileRef(Filename, openFile, CacheFailure);
198 if (Result)
199 return &Result->getFileEntry();
200 return llvm::errorToErrorCode(Result.takeError());
201}
202
203llvm::Expected<FileEntryRef>
204FileManager::getFileRef(StringRef Filename, bool openFile, bool CacheFailure) {
205 ++NumFileLookups;
206
207 // See if there is already an entry in the map.
208 auto SeenFileInsertResult =
209 SeenFileEntries.insert({Filename, std::errc::no_such_file_or_directory});
210 if (!SeenFileInsertResult.second) {
211 if (!SeenFileInsertResult.first->second)
212 return llvm::errorCodeToError(
213 SeenFileInsertResult.first->second.getError());
214 // Construct and return and FileEntryRef, unless it's a redirect to another
215 // filename.
216 FileEntryRef::MapValue Value = *SeenFileInsertResult.first->second;
217 if (LLVM_LIKELY(Value.V.is<FileEntry *>())__builtin_expect((bool)(Value.V.is<FileEntry *>()), true
))
218 return FileEntryRef(*SeenFileInsertResult.first);
219 return FileEntryRef(*reinterpret_cast<const FileEntryRef::MapEntry *>(
220 Value.V.get<const void *>()));
221 }
222
223 // We've not seen this before. Fill it in.
224 ++NumFileCacheMisses;
225 auto *NamedFileEnt = &*SeenFileInsertResult.first;
226 assert(!NamedFileEnt->second && "should be newly-created")((void)0);
227
228 // Get the null-terminated file name as stored as the key of the
229 // SeenFileEntries map.
230 StringRef InterndFileName = NamedFileEnt->first();
231
232 // Look up the directory for the file. When looking up something like
233 // sys/foo.h we'll discover all of the search directories that have a 'sys'
234 // subdirectory. This will let us avoid having to waste time on known-to-fail
235 // searches when we go to find sys/bar.h, because all the search directories
236 // without a 'sys' subdir will get a cached failure result.
237 auto DirInfoOrErr = getDirectoryFromFile(*this, Filename, CacheFailure);
238 if (!DirInfoOrErr) { // Directory doesn't exist, file can't exist.
239 std::error_code Err = errorToErrorCode(DirInfoOrErr.takeError());
240 if (CacheFailure)
241 NamedFileEnt->second = Err;
242 else
243 SeenFileEntries.erase(Filename);
244
245 return llvm::errorCodeToError(Err);
246 }
247 DirectoryEntryRef DirInfo = *DirInfoOrErr;
248
249 // FIXME: Use the directory info to prune this, before doing the stat syscall.
250 // FIXME: This will reduce the # syscalls.
251
252 // Check to see if the file exists.
253 std::unique_ptr<llvm::vfs::File> F;
254 llvm::vfs::Status Status;
255 auto statError = getStatValue(InterndFileName, Status, true,
256 openFile ? &F : nullptr);
257 if (statError) {
258 // There's no real file at the given path.
259 if (CacheFailure)
260 NamedFileEnt->second = statError;
261 else
262 SeenFileEntries.erase(Filename);
263
264 return llvm::errorCodeToError(statError);
265 }
266
267 assert((openFile || !F) && "undesired open file")((void)0);
268
269 // It exists. See if we have already opened a file with the same inode.
270 // This occurs when one dir is symlinked to another, for example.
271 FileEntry &UFE = UniqueRealFiles[Status.getUniqueID()];
272
273 if (Status.getName() == Filename) {
274 // The name matches. Set the FileEntry.
275 NamedFileEnt->second = FileEntryRef::MapValue(UFE, DirInfo);
276 } else {
277 // Name mismatch. We need a redirect. First grab the actual entry we want
278 // to return.
279 auto &Redirection =
280 *SeenFileEntries
281 .insert({Status.getName(), FileEntryRef::MapValue(UFE, DirInfo)})
282 .first;
283 assert(Redirection.second->V.is<FileEntry *>() &&((void)0)
284 "filename redirected to a non-canonical filename?")((void)0);
285 assert(Redirection.second->V.get<FileEntry *>() == &UFE &&((void)0)
286 "filename from getStatValue() refers to wrong file")((void)0);
287
288 // Cache the redirection in the previously-inserted entry, still available
289 // in the tentative return value.
290 NamedFileEnt->second = FileEntryRef::MapValue(Redirection);
291
292 // Fix the tentative return value.
293 NamedFileEnt = &Redirection;
294 }
295
296 FileEntryRef ReturnedRef(*NamedFileEnt);
297 if (UFE.isValid()) { // Already have an entry with this inode, return it.
298
299 // FIXME: this hack ensures that if we look up a file by a virtual path in
300 // the VFS that the getDir() will have the virtual path, even if we found
301 // the file by a 'real' path first. This is required in order to find a
302 // module's structure when its headers/module map are mapped in the VFS.
303 // We should remove this as soon as we can properly support a file having
304 // multiple names.
305 if (&DirInfo.getDirEntry() != UFE.Dir && Status.IsVFSMapped)
306 UFE.Dir = &DirInfo.getDirEntry();
307
308 // Always update LastRef to the last name by which a file was accessed.
309 // FIXME: Neither this nor always using the first reference is correct; we
310 // want to switch towards a design where we return a FileName object that
311 // encapsulates both the name by which the file was accessed and the
312 // corresponding FileEntry.
313 // FIXME: LastRef should be removed from FileEntry once all clients adopt
314 // FileEntryRef.
315 UFE.LastRef = ReturnedRef;
316
317 return ReturnedRef;
318 }
319
320 // Otherwise, we don't have this file yet, add it.
321 UFE.LastRef = ReturnedRef;
322 UFE.Size = Status.getSize();
323 UFE.ModTime = llvm::sys::toTimeT(Status.getLastModificationTime());
324 UFE.Dir = &DirInfo.getDirEntry();
325 UFE.UID = NextFileUID++;
326 UFE.UniqueID = Status.getUniqueID();
327 UFE.IsNamedPipe = Status.getType() == llvm::sys::fs::file_type::fifo_file;
328 UFE.File = std::move(F);
329 UFE.IsValid = true;
330
331 if (UFE.File) {
332 if (auto PathName = UFE.File->getName())
333 fillRealPathName(&UFE, *PathName);
334 } else if (!openFile) {
335 // We should still fill the path even if we aren't opening the file.
336 fillRealPathName(&UFE, InterndFileName);
337 }
338 return ReturnedRef;
339}
340
341llvm::Expected<FileEntryRef> FileManager::getSTDIN() {
342 // Only read stdin once.
343 if (STDIN)
344 return *STDIN;
345
346 std::unique_ptr<llvm::MemoryBuffer> Content;
347 if (auto ContentOrError = llvm::MemoryBuffer::getSTDIN())
348 Content = std::move(*ContentOrError);
349 else
350 return llvm::errorCodeToError(ContentOrError.getError());
351
352 STDIN = getVirtualFileRef(Content->getBufferIdentifier(),
353 Content->getBufferSize(), 0);
354 FileEntry &FE = const_cast<FileEntry &>(STDIN->getFileEntry());
355 FE.Content = std::move(Content);
356 FE.IsNamedPipe = true;
357 return *STDIN;
358}
359
360const FileEntry *FileManager::getVirtualFile(StringRef Filename, off_t Size,
361 time_t ModificationTime) {
362 return &getVirtualFileRef(Filename, Size, ModificationTime).getFileEntry();
1
Calling 'FileManager::getVirtualFileRef'
→
363}
364
365FileEntryRef FileManager::getVirtualFileRef(StringRef Filename, off_t Size,
366 time_t ModificationTime) {
367 ++NumFileLookups;
368
369 // See if there is already an entry in the map for an existing file.
370 auto &NamedFileEnt = *SeenFileEntries.insert(
371 {Filename, std::errc::no_such_file_or_directory}).first;
372 if (NamedFileEnt.second) {
2
←
Taking false branch
→
373 FileEntryRef::MapValue Value = *NamedFileEnt.second;
374 if (LLVM_LIKELY(Value.V.is<FileEntry *>())__builtin_expect((bool)(Value.V.is<FileEntry *>()), true
))
375 return FileEntryRef(NamedFileEnt);
376 return FileEntryRef(*reinterpret_cast<const FileEntryRef::MapEntry *>(
377 Value.V.get<const void *>()));
378 }
379
380 // We've not seen this before, or the file is cached as non-existent.
381 ++NumFileCacheMisses;
382 addAncestorsAsVirtualDirs(Filename);
383 FileEntry *UFE = nullptr;
384
385 // Now that all ancestors of Filename are in the cache, the
386 // following call is guaranteed to find the DirectoryEntry from the
387 // cache. A virtual file can also have an empty filename, that could come
388 // from a source location preprocessor directive with an empty filename as
389 // an example, so we need to pretend it has a name to ensure a valid directory
390 // entry can be returned.
391 auto DirInfo = expectedToOptional(getDirectoryFromFile(
5
←
Calling 'expectedToOptional<clang::DirectoryEntryRef>'
→
16
←
Returning from 'expectedToOptional<clang::DirectoryEntryRef>'
→
392 *this, Filename.empty() ? "." : Filename, /*CacheFailure=*/true));
3
←
Assuming the condition is false
→
4
←
'?' condition is false
→
393 assert(DirInfo &&((void)0)
394 "The directory of a virtual file should already be in the cache.")((void)0);
395
396 // Check to see if the file exists. If so, drop the virtual file
397 llvm::vfs::Status Status;
398 const char *InterndFileName = NamedFileEnt.first().data();
399 if (!getStatValue(InterndFileName, Status, true, nullptr)) {
17
←
Taking false branch
→
400 UFE = &UniqueRealFiles[Status.getUniqueID()];
401 Status = llvm::vfs::Status(
402 Status.getName(), Status.getUniqueID(),
403 llvm::sys::toTimePoint(ModificationTime),
404 Status.getUser(), Status.getGroup(), Size,
405 Status.getType(), Status.getPermissions());
406
407 NamedFileEnt.second = FileEntryRef::MapValue(*UFE, *DirInfo);
408
409 // If we had already opened this file, close it now so we don't
410 // leak the descriptor. We're not going to use the file
411 // descriptor anyway, since this is a virtual file.
412 if (UFE->File)
413 UFE->closeFile();
414
415 // If we already have an entry with this inode, return it.
416 //
417 // FIXME: Surely this should add a reference by the new name, and return
418 // it instead...
419 if (UFE->isValid())
420 return FileEntryRef(NamedFileEnt);
421
422 UFE->UniqueID = Status.getUniqueID();
423 UFE->IsNamedPipe = Status.getType() == llvm::sys::fs::file_type::fifo_file;
424 fillRealPathName(UFE, Status.getName());
425 } else {
426 VirtualFileEntries.push_back(std::make_unique<FileEntry>());
427 UFE = VirtualFileEntries.back().get();
428 NamedFileEnt.second = FileEntryRef::MapValue(*UFE, *DirInfo);
429 }
430
431 UFE->LastRef = FileEntryRef(NamedFileEnt);
432 UFE->Size = Size;
433 UFE->ModTime = ModificationTime;
434 UFE->Dir = &DirInfo->getDirEntry();
18
←
Calling 'DirectoryEntryRef::getDirEntry'
→
435 UFE->UID = NextFileUID++;
436 UFE->IsValid = true;
437 UFE->File.reset();
438 return FileEntryRef(NamedFileEnt);
439}
440
441llvm::Optional<FileEntryRef> FileManager::getBypassFile(FileEntryRef VF) {
442 // Stat of the file and return nullptr if it doesn't exist.
443 llvm::vfs::Status Status;
444 if (getStatValue(VF.getName(), Status, /*isFile=*/true, /*F=*/nullptr))
445 return None;
446
447 if (!SeenBypassFileEntries)
448 SeenBypassFileEntries = std::make_unique<
449 llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>>>();
450
451 // If we've already bypassed just use the existing one.
452 auto Insertion = SeenBypassFileEntries->insert(
453 {VF.getName(), std::errc::no_such_file_or_directory});
454 if (!Insertion.second)
455 return FileEntryRef(*Insertion.first);
456
457 // Fill in the new entry from the stat.
458 BypassFileEntries.push_back(std::make_unique<FileEntry>());
459 const FileEntry &VFE = VF.getFileEntry();
460 FileEntry &BFE = *BypassFileEntries.back();
461 Insertion.first->second = FileEntryRef::MapValue(BFE, VF.getDir());
462 BFE.LastRef = FileEntryRef(*Insertion.first);
463 BFE.Size = Status.getSize();
464 BFE.Dir = VFE.Dir;
465 BFE.ModTime = llvm::sys::toTimeT(Status.getLastModificationTime());
466 BFE.UID = NextFileUID++;
467 BFE.IsValid = true;
468
469 // Save the entry in the bypass table and return.
470 return FileEntryRef(*Insertion.first);
471}
472
473bool FileManager::FixupRelativePath(SmallVectorImpl<char> &path) const {
474 StringRef pathRef(path.data(), path.size());
475
476 if (FileSystemOpts.WorkingDir.empty()
477 || llvm::sys::path::is_absolute(pathRef))
478 return false;
479
480 SmallString<128> NewPath(FileSystemOpts.WorkingDir);
481 llvm::sys::path::append(NewPath, pathRef);
482 path = NewPath;
483 return true;
484}
485
486bool FileManager::makeAbsolutePath(SmallVectorImpl<char> &Path) const {
487 bool Changed = FixupRelativePath(Path);
488
489 if (!llvm::sys::path::is_absolute(StringRef(Path.data(), Path.size()))) {
490 FS->makeAbsolute(Path);
491 Changed = true;
492 }
493
494 return Changed;
495}
496
497void FileManager::fillRealPathName(FileEntry *UFE, llvm::StringRef FileName) {
498 llvm::SmallString<128> AbsPath(FileName);
499 // This is not the same as `VFS::getRealPath()`, which resolves symlinks
500 // but can be very expensive on real file systems.
501 // FIXME: the semantic of RealPathName is unclear, and the name might be
502 // misleading. We need to clean up the interface here.
503 makeAbsolutePath(AbsPath);
504 llvm::sys::path::remove_dots(AbsPath, /*remove_dot_dot=*/true);
505 UFE->RealPathName = std::string(AbsPath.str());
506}
507
508llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
509FileManager::getBufferForFile(const FileEntry *Entry, bool isVolatile,
510 bool RequiresNullTerminator) {
511 // If the content is living on the file entry, return a reference to it.
512 if (Entry->Content)
513 return llvm::MemoryBuffer::getMemBuffer(Entry->Content->getMemBufferRef());
514
515 uint64_t FileSize = Entry->getSize();
516 // If there's a high enough chance that the file have changed since we
517 // got its size, force a stat before opening it.
518 if (isVolatile || Entry->isNamedPipe())
519 FileSize = -1;
520
521 StringRef Filename = Entry->getName();
522 // If the file is already open, use the open file descriptor.
523 if (Entry->File) {
524 auto Result = Entry->File->getBuffer(Filename, FileSize,
525 RequiresNullTerminator, isVolatile);
526 Entry->closeFile();
527 return Result;
528 }
529
530 // Otherwise, open the file.
531 return getBufferForFileImpl(Filename, FileSize, isVolatile,
532 RequiresNullTerminator);
533}
534
535llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
536FileManager::getBufferForFileImpl(StringRef Filename, int64_t FileSize,
537 bool isVolatile,
538 bool RequiresNullTerminator) {
539 if (FileSystemOpts.WorkingDir.empty())
540 return FS->getBufferForFile(Filename, FileSize, RequiresNullTerminator,
541 isVolatile);
542
543 SmallString<128> FilePath(Filename);
544 FixupRelativePath(FilePath);
545 return FS->getBufferForFile(FilePath, FileSize, RequiresNullTerminator,
546 isVolatile);
547}
548
549/// getStatValue - Get the 'stat' information for the specified path,
550/// using the cache to accelerate it if possible. This returns true
551/// if the path points to a virtual file or does not exist, or returns
552/// false if it's an existent real file. If FileDescriptor is NULL,
553/// do directory look-up instead of file look-up.
554std::error_code
555FileManager::getStatValue(StringRef Path, llvm::vfs::Status &Status,
556 bool isFile, std::unique_ptr<llvm::vfs::File> *F) {
557 // FIXME: FileSystemOpts shouldn't be passed in here, all paths should be
558 // absolute!
559 if (FileSystemOpts.WorkingDir.empty())
560 return FileSystemStatCache::get(Path, Status, isFile, F,
561 StatCache.get(), *FS);
562
563 SmallString<128> FilePath(Path);
564 FixupRelativePath(FilePath);
565
566 return FileSystemStatCache::get(FilePath.c_str(), Status, isFile, F,
567 StatCache.get(), *FS);
568}
569
570std::error_code
571FileManager::getNoncachedStatValue(StringRef Path,
572 llvm::vfs::Status &Result) {
573 SmallString<128> FilePath(Path);
574 FixupRelativePath(FilePath);
575
576 llvm::ErrorOr<llvm::vfs::Status> S = FS->status(FilePath.c_str());
577 if (!S)
578 return S.getError();
579 Result = *S;
580 return std::error_code();
581}
582
583void FileManager::GetUniqueIDMapping(
584 SmallVectorImpl<const FileEntry *> &UIDToFiles) const {
585 UIDToFiles.clear();
586 UIDToFiles.resize(NextFileUID);
587
588 // Map file entries
589 for (llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>,
590 llvm::BumpPtrAllocator>::const_iterator
591 FE = SeenFileEntries.begin(),
592 FEEnd = SeenFileEntries.end();
593 FE != FEEnd; ++FE)
594 if (llvm::ErrorOr<FileEntryRef::MapValue> Entry = FE->getValue()) {
595 if (const auto *FE = Entry->V.dyn_cast<FileEntry *>())
596 UIDToFiles[FE->getUID()] = FE;
597 }
598
599 // Map virtual file entries
600 for (const auto &VFE : VirtualFileEntries)
601 UIDToFiles[VFE->getUID()] = VFE.get();
602}
603
604StringRef FileManager::getCanonicalName(const DirectoryEntry *Dir) {
605 llvm::DenseMap<const void *, llvm::StringRef>::iterator Known
606 = CanonicalNames.find(Dir);
607 if (Known != CanonicalNames.end())
608 return Known->second;
609
610 StringRef CanonicalName(Dir->getName());
611
612 SmallString<4096> CanonicalNameBuf;
613 if (!FS->getRealPath(Dir->getName(), CanonicalNameBuf))
614 CanonicalName = CanonicalNameBuf.str().copy(CanonicalNameStorage);
615
616 CanonicalNames.insert({Dir, CanonicalName});
617 return CanonicalName;
618}
619
620StringRef FileManager::getCanonicalName(const FileEntry *File) {
621 llvm::DenseMap<const void *, llvm::StringRef>::iterator Known
622 = CanonicalNames.find(File);
623 if (Known != CanonicalNames.end())
624 return Known->second;
625
626 StringRef CanonicalName(File->getName());
627
628 SmallString<4096> CanonicalNameBuf;
629 if (!FS->getRealPath(File->getName(), CanonicalNameBuf))
630 CanonicalName = CanonicalNameBuf.str().copy(CanonicalNameStorage);
631
632 CanonicalNames.insert({File, CanonicalName});
633 return CanonicalName;
634}
635
636void FileManager::PrintStats() const {
637 llvm::errs() << "\n*** File Manager Stats:\n";
638 llvm::errs() << UniqueRealFiles.size() << " real files found, "
639 << UniqueRealDirs.size() << " real dirs found.\n";
640 llvm::errs() << VirtualFileEntries.size() << " virtual files found, "
641 << VirtualDirectoryEntries.size() << " virtual dirs found.\n";
642 llvm::errs() << NumDirLookups << " dir lookups, "
643 << NumDirCacheMisses << " dir cache misses.\n";
644 llvm::errs() << NumFileLookups << " file lookups, "
645 << NumFileCacheMisses << " file cache misses.\n";
646
647 //llvm::errs() << PagesMapped << BytesOfPagesMapped << FSLookups;
648}
←

/usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/llvm/include/llvm/Support/Error.h

→
1//===- llvm/Support/Error.h - Recoverable error handling --------*- C++ -*-===//
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// This file defines an API used to report recoverable errors.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_SUPPORT_ERROR_H
14#define LLVM_SUPPORT_ERROR_H
15
16#include "llvm-c/Error.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringExtras.h"
20#include "llvm/ADT/Twine.h"
21#include "llvm/Config/abi-breaking.h"
22#include "llvm/Support/AlignOf.h"
23#include "llvm/Support/Compiler.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/ErrorHandling.h"
26#include "llvm/Support/ErrorOr.h"
27#include "llvm/Support/Format.h"
28#include "llvm/Support/raw_ostream.h"
29#include <algorithm>
30#include <cassert>
31#include <cstdint>
32#include <cstdlib>
33#include <functional>
34#include <memory>
35#include <new>
36#include <string>
37#include <system_error>
38#include <type_traits>
39#include <utility>
40#include <vector>
41
42namespace llvm {
43
44class ErrorSuccess;
45
46/// Base class for error info classes. Do not extend this directly: Extend
47/// the ErrorInfo template subclass instead.
48class ErrorInfoBase {
49public:
50 virtual ~ErrorInfoBase() = default;
51
52 /// Print an error message to an output stream.
53 virtual void log(raw_ostream &OS) const = 0;
54
55 /// Return the error message as a string.
56 virtual std::string message() const {
57 std::string Msg;
58 raw_string_ostream OS(Msg);
59 log(OS);
60 return OS.str();
61 }
62
63 /// Convert this error to a std::error_code.
64 ///
65 /// This is a temporary crutch to enable interaction with code still
66 /// using std::error_code. It will be removed in the future.
67 virtual std::error_code convertToErrorCode() const = 0;
68
69 // Returns the class ID for this type.
70 static const void *classID() { return &ID; }
71
72 // Returns the class ID for the dynamic type of this ErrorInfoBase instance.
73 virtual const void *dynamicClassID() const = 0;
74
75 // Check whether this instance is a subclass of the class identified by
76 // ClassID.
77 virtual bool isA(const void *const ClassID) const {
78 return ClassID == classID();
79 }
80
81 // Check whether this instance is a subclass of ErrorInfoT.
82 template <typename ErrorInfoT> bool isA() const {
83 return isA(ErrorInfoT::classID());
84 }
85
86private:
87 virtual void anchor();
88
89 static char ID;
90};
91
92/// Lightweight error class with error context and mandatory checking.
93///
94/// Instances of this class wrap a ErrorInfoBase pointer. Failure states
95/// are represented by setting the pointer to a ErrorInfoBase subclass
96/// instance containing information describing the failure. Success is
97/// represented by a null pointer value.
98///
99/// Instances of Error also contains a 'Checked' flag, which must be set
100/// before the destructor is called, otherwise the destructor will trigger a
101/// runtime error. This enforces at runtime the requirement that all Error
102/// instances be checked or returned to the caller.
103///
104/// There are two ways to set the checked flag, depending on what state the
105/// Error instance is in. For Error instances indicating success, it
106/// is sufficient to invoke the boolean conversion operator. E.g.:
107///
108/// @code{.cpp}
109/// Error foo(<...>);
110///
111/// if (auto E = foo(<...>))
112/// return E; // <- Return E if it is in the error state.
113/// // We have verified that E was in the success state. It can now be safely
114/// // destroyed.
115/// @endcode
116///
117/// A success value *can not* be dropped. For example, just calling 'foo(<...>)'
118/// without testing the return value will raise a runtime error, even if foo
119/// returns success.
120///
121/// For Error instances representing failure, you must use either the
122/// handleErrors or handleAllErrors function with a typed handler. E.g.:
123///
124/// @code{.cpp}
125/// class MyErrorInfo : public ErrorInfo<MyErrorInfo> {
126/// // Custom error info.
127/// };
128///
129/// Error foo(<...>) { return make_error<MyErrorInfo>(...); }
130///
131/// auto E = foo(<...>); // <- foo returns failure with MyErrorInfo.
132/// auto NewE =
133/// handleErrors(E,
134/// [](const MyErrorInfo &M) {
135/// // Deal with the error.
136/// },
137/// [](std::unique_ptr<OtherError> M) -> Error {
138/// if (canHandle(*M)) {
139/// // handle error.
140/// return Error::success();
141/// }
142/// // Couldn't handle this error instance. Pass it up the stack.
143/// return Error(std::move(M));
144/// );
145/// // Note - we must check or return NewE in case any of the handlers
146/// // returned a new error.
147/// @endcode
148///
149/// The handleAllErrors function is identical to handleErrors, except
150/// that it has a void return type, and requires all errors to be handled and
151/// no new errors be returned. It prevents errors (assuming they can all be
152/// handled) from having to be bubbled all the way to the top-level.
153///
154/// *All* Error instances must be checked before destruction, even if
155/// they're moved-assigned or constructed from Success values that have already
156/// been checked. This enforces checking through all levels of the call stack.
157class LLVM_NODISCARD[[clang::warn_unused_result]] Error {
158 // ErrorList needs to be able to yank ErrorInfoBase pointers out of Errors
159 // to add to the error list. It can't rely on handleErrors for this, since
160 // handleErrors does not support ErrorList handlers.
161 friend class ErrorList;
162
163 // handleErrors needs to be able to set the Checked flag.
164 template <typename... HandlerTs>
165 friend Error handleErrors(Error E, HandlerTs &&... Handlers);
166
167 // Expected<T> needs to be able to steal the payload when constructed from an
168 // error.
169 template <typename T> friend class Expected;
170
171 // wrap needs to be able to steal the payload.
172 friend LLVMErrorRef wrap(Error);
173
174protected:
175 /// Create a success value. Prefer using 'Error::success()' for readability
176 Error() {
177 setPtr(nullptr);
178 setChecked(false);
179 }
180
181public:
182 /// Create a success value.
183 static ErrorSuccess success();
184
185 // Errors are not copy-constructable.
186 Error(const Error &Other) = delete;
187
188 /// Move-construct an error value. The newly constructed error is considered
189 /// unchecked, even if the source error had been checked. The original error
190 /// becomes a checked Success value, regardless of its original state.
191 Error(Error &&Other) {
192 setChecked(true);
193 *this = std::move(Other);
194 }
195
196 /// Create an error value. Prefer using the 'make_error' function, but
197 /// this constructor can be useful when "re-throwing" errors from handlers.
198 Error(std::unique_ptr<ErrorInfoBase> Payload) {
199 setPtr(Payload.release());
200 setChecked(false);
201 }
202
203 // Errors are not copy-assignable.
204 Error &operator=(const Error &Other) = delete;
205
206 /// Move-assign an error value. The current error must represent success, you
207 /// you cannot overwrite an unhandled error. The current error is then
208 /// considered unchecked. The source error becomes a checked success value,
209 /// regardless of its original state.
210 Error &operator=(Error &&Other) {
211 // Don't allow overwriting of unchecked values.
212 assertIsChecked();
213 setPtr(Other.getPtr());
214
215 // This Error is unchecked, even if the source error was checked.
216 setChecked(false);
217
218 // Null out Other's payload and set its checked bit.
219 Other.setPtr(nullptr);
220 Other.setChecked(true);
221
222 return *this;
223 }
224
225 /// Destroy a Error. Fails with a call to abort() if the error is
226 /// unchecked.
227 ~Error() {
228 assertIsChecked();
229 delete getPtr();
230 }
231
232 /// Bool conversion. Returns true if this Error is in a failure state,
233 /// and false if it is in an accept state. If the error is in a Success state
234 /// it will be considered checked.
235 explicit operator bool() {
236 setChecked(getPtr() == nullptr);
237 return getPtr() != nullptr;
238 }
239
240 /// Check whether one error is a subclass of another.
241 template <typename ErrT> bool isA() const {
242 return getPtr() && getPtr()->isA(ErrT::classID());
243 }
244
245 /// Returns the dynamic class id of this error, or null if this is a success
246 /// value.
247 const void* dynamicClassID() const {
248 if (!getPtr())
249 return nullptr;
250 return getPtr()->dynamicClassID();
251 }
252
253private:
254#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
255 // assertIsChecked() happens very frequently, but under normal circumstances
256 // is supposed to be a no-op. So we want it to be inlined, but having a bunch
257 // of debug prints can cause the function to be too large for inlining. So
258 // it's important that we define this function out of line so that it can't be
259 // inlined.
260 LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
261 void fatalUncheckedError() const;
262#endif
263
264 void assertIsChecked() {
265#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
266 if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false))
267 fatalUncheckedError();
268#endif
269 }
270
271 ErrorInfoBase *getPtr() const {
272#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
273 return reinterpret_cast<ErrorInfoBase*>(
274 reinterpret_cast<uintptr_t>(Payload) &
275 ~static_cast<uintptr_t>(0x1));
276#else
277 return Payload;
278#endif
279 }
280
281 void setPtr(ErrorInfoBase *EI) {
282#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
283 Payload = reinterpret_cast<ErrorInfoBase*>(
284 (reinterpret_cast<uintptr_t>(EI) &
285 ~static_cast<uintptr_t>(0x1)) |
286 (reinterpret_cast<uintptr_t>(Payload) & 0x1));
287#else
288 Payload = EI;
289#endif
290 }
291
292 bool getChecked() const {
293#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
294 return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
295#else
296 return true;
297#endif
298 }
299
300 void setChecked(bool V) {
301#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
302 Payload = reinterpret_cast<ErrorInfoBase*>(
303 (reinterpret_cast<uintptr_t>(Payload) &
304 ~static_cast<uintptr_t>(0x1)) |
305 (V ? 0 : 1));
306#endif
307 }
308
309 std::unique_ptr<ErrorInfoBase> takePayload() {
310 std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
311 setPtr(nullptr);
312 setChecked(true);
313 return Tmp;
314 }
315
316 friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) {
317 if (auto P = E.getPtr())
318 P->log(OS);
319 else
320 OS << "success";
321 return OS;
322 }
323
324 ErrorInfoBase *Payload = nullptr;
325};
326
327/// Subclass of Error for the sole purpose of identifying the success path in
328/// the type system. This allows to catch invalid conversion to Expected<T> at
329/// compile time.
330class ErrorSuccess final : public Error {};
331
332inline ErrorSuccess Error::success() { return ErrorSuccess(); }
333
334/// Make a Error instance representing failure using the given error info
335/// type.
336template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) {
337 return Error(std::make_unique<ErrT>(std::forward<ArgTs>(Args)...));
338}
339
340/// Base class for user error types. Users should declare their error types
341/// like:
342///
343/// class MyError : public ErrorInfo<MyError> {
344/// ....
345/// };
346///
347/// This class provides an implementation of the ErrorInfoBase::kind
348/// method, which is used by the Error RTTI system.
349template <typename ThisErrT, typename ParentErrT = ErrorInfoBase>
350class ErrorInfo : public ParentErrT {
351public:
352 using ParentErrT::ParentErrT; // inherit constructors
353
354 static const void *classID() { return &ThisErrT::ID; }
355
356 const void *dynamicClassID() const override { return &ThisErrT::ID; }
357
358 bool isA(const void *const ClassID) const override {
359 return ClassID == classID() || ParentErrT::isA(ClassID);
360 }
361};
362
363/// Special ErrorInfo subclass representing a list of ErrorInfos.
364/// Instances of this class are constructed by joinError.
365class ErrorList final : public ErrorInfo<ErrorList> {
366 // handleErrors needs to be able to iterate the payload list of an
367 // ErrorList.
368 template <typename... HandlerTs>
369 friend Error handleErrors(Error E, HandlerTs &&... Handlers);
370
371 // joinErrors is implemented in terms of join.
372 friend Error joinErrors(Error, Error);
373
374public:
375 void log(raw_ostream &OS) const override {
376 OS << "Multiple errors:\n";
377 for (auto &ErrPayload : Payloads) {
378 ErrPayload->log(OS);
379 OS << "\n";
380 }
381 }
382
383 std::error_code convertToErrorCode() const override;
384
385 // Used by ErrorInfo::classID.
386 static char ID;
387
388private:
389 ErrorList(std::unique_ptr<ErrorInfoBase> Payload1,
390 std::unique_ptr<ErrorInfoBase> Payload2) {
391 assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((void)0)
392 "ErrorList constructor payloads should be singleton errors")((void)0);
393 Payloads.push_back(std::move(Payload1));
394 Payloads.push_back(std::move(Payload2));
395 }
396
397 static Error join(Error E1, Error E2) {
398 if (!E1)
399 return E2;
400 if (!E2)
401 return E1;
402 if (E1.isA<ErrorList>()) {
403 auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
404 if (E2.isA<ErrorList>()) {
405 auto E2Payload = E2.takePayload();
406 auto &E2List = static_cast<ErrorList &>(*E2Payload);
407 for (auto &Payload : E2List.Payloads)
408 E1List.Payloads.push_back(std::move(Payload));
409 } else
410 E1List.Payloads.push_back(E2.takePayload());
411
412 return E1;
413 }
414 if (E2.isA<ErrorList>()) {
415 auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
416 E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload());
417 return E2;
418 }
419 return Error(std::unique_ptr<ErrorList>(
420 new ErrorList(E1.takePayload(), E2.takePayload())));
421 }
422
423 std::vector<std::unique_ptr<ErrorInfoBase>> Payloads;
424};
425
426/// Concatenate errors. The resulting Error is unchecked, and contains the
427/// ErrorInfo(s), if any, contained in E1, followed by the
428/// ErrorInfo(s), if any, contained in E2.
429inline Error joinErrors(Error E1, Error E2) {
430 return ErrorList::join(std::move(E1), std::move(E2));
431}
432
433/// Tagged union holding either a T or a Error.
434///
435/// This class parallels ErrorOr, but replaces error_code with Error. Since
436/// Error cannot be copied, this class replaces getError() with
437/// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the
438/// error class type.
439///
440/// Example usage of 'Expected<T>' as a function return type:
441///
442/// @code{.cpp}
443/// Expected<int> myDivide(int A, int B) {
444/// if (B == 0) {
445/// // return an Error
446/// return createStringError(inconvertibleErrorCode(),
447/// "B must not be zero!");
448/// }
449/// // return an integer
450/// return A / B;
451/// }
452/// @endcode
453///
454/// Checking the results of to a function returning 'Expected<T>':
455/// @code{.cpp}
456/// if (auto E = Result.takeError()) {
457/// // We must consume the error. Typically one of:
458/// // - return the error to our caller
459/// // - toString(), when logging
460/// // - consumeError(), to silently swallow the error
461/// // - handleErrors(), to distinguish error types
462/// errs() << "Problem with division " << toString(std::move(E)) << "\n";
463/// return;
464/// }
465/// // use the result
466/// outs() << "The answer is " << *Result << "\n";
467/// @endcode
468///
469/// For unit-testing a function returning an 'Expceted<T>', see the
470/// 'EXPECT_THAT_EXPECTED' macros in llvm/Testing/Support/Error.h
471
472template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected {
473 template <class T1> friend class ExpectedAsOutParameter;
474 template <class OtherT> friend class Expected;
475
476 static constexpr bool isRef = std::is_reference<T>::value;
477
478 using wrap = std::reference_wrapper<std::remove_reference_t<T>>;
479
480 using error_type = std::unique_ptr<ErrorInfoBase>;
481
482public:
483 using storage_type = std::conditional_t<isRef, wrap, T>;
484 using value_type = T;
485
486private:
487 using reference = std::remove_reference_t<T> &;
488 using const_reference = const std::remove_reference_t<T> &;
489 using pointer = std::remove_reference_t<T> *;
490 using const_pointer = const std::remove_reference_t<T> *;
491
492public:
493 /// Create an Expected<T> error value from the given Error.
494 Expected(Error Err)
495 : HasError(true)
496#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
497 // Expected is unchecked upon construction in Debug builds.
498 , Unchecked(true)
499#endif
500 {
501 assert(Err && "Cannot create Expected<T> from Error success value.")((void)0);
502 new (getErrorStorage()) error_type(Err.takePayload());
503 }
504
505 /// Forbid to convert from Error::success() implicitly, this avoids having
506 /// Expected<T> foo() { return Error::success(); } which compiles otherwise
507 /// but triggers the assertion above.
508 Expected(ErrorSuccess) = delete;
509
510 /// Create an Expected<T> success value from the given OtherT value, which
511 /// must be convertible to T.
512 template <typename OtherT>
513 Expected(OtherT &&Val,
514 std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr)
515 : HasError(false)
516#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
517 // Expected is unchecked upon construction in Debug builds.
518 ,
519 Unchecked(true)
520#endif
521 {
522 new (getStorage()) storage_type(std::forward<OtherT>(Val));
523 }
524
525 /// Move construct an Expected<T> value.
526 Expected(Expected &&Other) { moveConstruct(std::move(Other)); }
527
528 /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
529 /// must be convertible to T.
530 template <class OtherT>
531 Expected(
532 Expected<OtherT> &&Other,
533 std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr) {
534 moveConstruct(std::move(Other));
535 }
536
537 /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
538 /// isn't convertible to T.
539 template <class OtherT>
540 explicit Expected(
541 Expected<OtherT> &&Other,
542 std::enable_if_t<!std::is_convertible<OtherT, T>::value> * = nullptr) {
543 moveConstruct(std::move(Other));
544 }
545
546 /// Move-assign from another Expected<T>.
547 Expected &operator=(Expected &&Other) {
548 moveAssign(std::move(Other));
549 return *this;
550 }
551
552 /// Destroy an Expected<T>.
553 ~Expected() {
554 assertIsChecked();
555 if (!HasError)
556 getStorage()->~storage_type();
557 else
558 getErrorStorage()->~error_type();
559 }
560
561 /// Return false if there is an error.
562 explicit operator bool() {
563#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
564 Unchecked = HasError;
565#endif
566 return !HasError;
567 }
568
569 /// Returns a reference to the stored T value.
570 reference get() {
571 assertIsChecked();
572 return *getStorage();
573 }
574
575 /// Returns a const reference to the stored T value.
576 const_reference get() const {
577 assertIsChecked();
578 return const_cast<Expected<T> *>(this)->get();
579 }
580
581 /// Check that this Expected<T> is an error of type ErrT.
582 template <typename ErrT> bool errorIsA() const {
583 return HasError && (*getErrorStorage())->template isA<ErrT>();
584 }
585
586 /// Take ownership of the stored error.
587 /// After calling this the Expected<T> is in an indeterminate state that can
588 /// only be safely destructed. No further calls (beside the destructor) should
589 /// be made on the Expected<T> value.
590 Error takeError() {
591#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
592 Unchecked = false;
593#endif
594 return HasError ? Error(std::move(*getErrorStorage())) : Error::success();
595 }
596
597 /// Returns a pointer to the stored T value.
598 pointer operator->() {
599 assertIsChecked();
600 return toPointer(getStorage());
601 }
602
603 /// Returns a const pointer to the stored T value.
604 const_pointer operator->() const {
605 assertIsChecked();
606 return toPointer(getStorage());
607 }
608
609 /// Returns a reference to the stored T value.
610 reference operator*() {
611 assertIsChecked();
612 return *getStorage();
613 }
614
615 /// Returns a const reference to the stored T value.
616 const_reference operator*() const {
617 assertIsChecked();
618 return *getStorage();
619 }
620
621private:
622 template <class T1>
623 static bool compareThisIfSameType(const T1 &a, const T1 &b) {
624 return &a == &b;
625 }
626
627 template <class T1, class T2>
628 static bool compareThisIfSameType(const T1 &, const T2 &) {
629 return false;
630 }
631
632 template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) {
633 HasError = Other.HasError;
634#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
635 Unchecked = true;
636 Other.Unchecked = false;
637#endif
638
639 if (!HasError)
640 new (getStorage()) storage_type(std::move(*Other.getStorage()));
641 else
642 new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage()));
643 }
644
645 template <class OtherT> void moveAssign(Expected<OtherT> &&Other) {
646 assertIsChecked();
647
648 if (compareThisIfSameType(*this, Other))
649 return;
650
651 this->~Expected();
652 new (this) Expected(std::move(Other));
653 }
654
655 pointer toPointer(pointer Val) { return Val; }
656
657 const_pointer toPointer(const_pointer Val) const { return Val; }
658
659 pointer toPointer(wrap *Val) { return &Val->get(); }
660
661 const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
662
663 storage_type *getStorage() {
664 assert(!HasError && "Cannot get value when an error exists!")((void)0);
665 return reinterpret_cast<storage_type *>(&TStorage);
666 }
667
668 const storage_type *getStorage() const {
669 assert(!HasError && "Cannot get value when an error exists!")((void)0);
670 return reinterpret_cast<const storage_type *>(&TStorage);
671 }
672
673 error_type *getErrorStorage() {
674 assert(HasError && "Cannot get error when a value exists!")((void)0);
675 return reinterpret_cast<error_type *>(&ErrorStorage);
676 }
677
678 const error_type *getErrorStorage() const {
679 assert(HasError && "Cannot get error when a value exists!")((void)0);
680 return reinterpret_cast<const error_type *>(&ErrorStorage);
681 }
682
683 // Used by ExpectedAsOutParameter to reset the checked flag.
684 void setUnchecked() {
685#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
686 Unchecked = true;
687#endif
688 }
689
690#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
691 LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
692 LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline))
693 void fatalUncheckedExpected() const {
694 dbgs() << "Expected<T> must be checked before access or destruction.\n";
695 if (HasError) {
696 dbgs() << "Unchecked Expected<T> contained error:\n";
697 (*getErrorStorage())->log(dbgs());
698 } else
699 dbgs() << "Expected<T> value was in success state. (Note: Expected<T> "
700 "values in success mode must still be checked prior to being "
701 "destroyed).\n";
702 abort();
703 }
704#endif
705
706 void assertIsChecked() const {
707#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
708 if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false))
709 fatalUncheckedExpected();
710#endif
711 }
712
713 union {
714 AlignedCharArrayUnion<storage_type> TStorage;
715 AlignedCharArrayUnion<error_type> ErrorStorage;
716 };
717 bool HasError : 1;
718#if LLVM_ENABLE_ABI_BREAKING_CHECKS0
719 bool Unchecked : 1;
720#endif
721};
722
723/// Report a serious error, calling any installed error handler. See
724/// ErrorHandling.h.
725LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err,
726 bool gen_crash_diag = true);
727
728/// Report a fatal error if Err is a failure value.
729///
730/// This function can be used to wrap calls to fallible functions ONLY when it
731/// is known that the Error will always be a success value. E.g.
732///
733/// @code{.cpp}
734/// // foo only attempts the fallible operation if DoFallibleOperation is
735/// // true. If DoFallibleOperation is false then foo always returns
736/// // Error::success().
737/// Error foo(bool DoFallibleOperation);
738///
739/// cantFail(foo(false));
740/// @endcode
741inline void cantFail(Error Err, const char *Msg = nullptr) {
742 if (Err) {
743 if (!Msg)
744 Msg = "Failure value returned from cantFail wrapped call";
745#ifndef NDEBUG1
746 std::string Str;
747 raw_string_ostream OS(Str);
748 OS << Msg << "\n" << Err;
749 Msg = OS.str().c_str();
750#endif
751 llvm_unreachable(Msg)__builtin_unreachable();
752 }
753}
754
755/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
756/// returns the contained value.
757///
758/// This function can be used to wrap calls to fallible functions ONLY when it
759/// is known that the Error will always be a success value. E.g.
760///
761/// @code{.cpp}
762/// // foo only attempts the fallible operation if DoFallibleOperation is
763/// // true. If DoFallibleOperation is false then foo always returns an int.
764/// Expected<int> foo(bool DoFallibleOperation);
765///
766/// int X = cantFail(foo(false));
767/// @endcode
768template <typename T>
769T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) {
770 if (ValOrErr)
771 return std::move(*ValOrErr);
772 else {
773 if (!Msg)
774 Msg = "Failure value returned from cantFail wrapped call";
775#ifndef NDEBUG1
776 std::string Str;
777 raw_string_ostream OS(Str);
778 auto E = ValOrErr.takeError();
779 OS << Msg << "\n" << E;
780 Msg = OS.str().c_str();
781#endif
782 llvm_unreachable(Msg)__builtin_unreachable();
783 }
784}
785
786/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
787/// returns the contained reference.
788///
789/// This function can be used to wrap calls to fallible functions ONLY when it
790/// is known that the Error will always be a success value. E.g.
791///
792/// @code{.cpp}
793/// // foo only attempts the fallible operation if DoFallibleOperation is
794/// // true. If DoFallibleOperation is false then foo always returns a Bar&.
795/// Expected<Bar&> foo(bool DoFallibleOperation);
796///
797/// Bar &X = cantFail(foo(false));
798/// @endcode
799template <typename T>
800T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) {
801 if (ValOrErr)
802 return *ValOrErr;
803 else {
804 if (!Msg)
805 Msg = "Failure value returned from cantFail wrapped call";
806#ifndef NDEBUG1
807 std::string Str;
808 raw_string_ostream OS(Str);
809 auto E = ValOrErr.takeError();
810 OS << Msg << "\n" << E;
811 Msg = OS.str().c_str();
812#endif
813 llvm_unreachable(Msg)__builtin_unreachable();
814 }
815}
816
817/// Helper for testing applicability of, and applying, handlers for
818/// ErrorInfo types.
819template <typename HandlerT>
820class ErrorHandlerTraits
821 : public ErrorHandlerTraits<decltype(
822 &std::remove_reference<HandlerT>::type::operator())> {};
823
824// Specialization functions of the form 'Error (const ErrT&)'.
825template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> {
826public:
827 static bool appliesTo(const ErrorInfoBase &E) {
828 return E.template isA<ErrT>();
829 }
830
831 template <typename HandlerT>
832 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
833 assert(appliesTo(*E) && "Applying incorrect handler")((void)0);
834 return H(static_cast<ErrT &>(*E));
835 }
836};
837
838// Specialization functions of the form 'void (const ErrT&)'.
839template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> {
840public:
841 static bool appliesTo(const ErrorInfoBase &E) {
842 return E.template isA<ErrT>();
843 }
844
845 template <typename HandlerT>
846 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
847 assert(appliesTo(*E) && "Applying incorrect handler")((void)0);
848 H(static_cast<ErrT &>(*E));
849 return Error::success();
850 }
851};
852
853/// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'.
854template <typename ErrT>
855class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> {
856public:
857 static bool appliesTo(const ErrorInfoBase &E) {
858 return E.template isA<ErrT>();
859 }
860
861 template <typename HandlerT>
862 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
863 assert(appliesTo(*E) && "Applying incorrect handler")((void)0);
864 std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
865 return H(std::move(SubE));
866 }
867};
868
869/// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'.
870template <typename ErrT>
871class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> {
872public:
873 static bool appliesTo(const ErrorInfoBase &E) {
874 return E.template isA<ErrT>();
875 }
876
877 template <typename HandlerT>
878 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
879 assert(appliesTo(*E) && "Applying incorrect handler")((void)0);
880 std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
881 H(std::move(SubE));
882 return Error::success();
883 }
884};
885
886// Specialization for member functions of the form 'RetT (const ErrT&)'.
887template <typename C, typename RetT, typename ErrT>
888class ErrorHandlerTraits<RetT (C::*)(ErrT &)>
889 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
890
891// Specialization for member functions of the form 'RetT (const ErrT&) const'.
892template <typename C, typename RetT, typename ErrT>
893class ErrorHandlerTraits<RetT (C::*)(ErrT &) const>
894 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
895
896// Specialization for member functions of the form 'RetT (const ErrT&)'.
897template <typename C, typename RetT, typename ErrT>
898class ErrorHandlerTraits<RetT (C::*)(const ErrT &)>
899 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
900
901// Specialization for member functions of the form 'RetT (const ErrT&) const'.
902template <typename C, typename RetT, typename ErrT>
903class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const>
904 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
905
906/// Specialization for member functions of the form
907/// 'RetT (std::unique_ptr<ErrT>)'.
908template <typename C, typename RetT, typename ErrT>
909class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)>
910 : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
911
912/// Specialization for member functions of the form
913/// 'RetT (std::unique_ptr<ErrT>) const'.
914template <typename C, typename RetT, typename ErrT>
915class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const>
916 : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
917
918inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) {
919 return Error(std::move(Payload));
920}
921
922template <typename HandlerT, typename... HandlerTs>
923Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload,
924 HandlerT &&Handler, HandlerTs &&... Handlers) {
925 if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload))
926 return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler),
927 std::move(Payload));
928 return handleErrorImpl(std::move(Payload),
929 std::forward<HandlerTs>(Handlers)...);
930}
931
932/// Pass the ErrorInfo(s) contained in E to their respective handlers. Any
933/// unhandled errors (or Errors returned by handlers) are re-concatenated and
934/// returned.
935/// Because this function returns an error, its result must also be checked
936/// or returned. If you intend to handle all errors use handleAllErrors
937/// (which returns void, and will abort() on unhandled errors) instead.
938template <typename... HandlerTs>
939Error handleErrors(Error E, HandlerTs &&... Hs) {
940 if (!E)
941 return Error::success();
942
943 std::unique_ptr<ErrorInfoBase> Payload = E.takePayload();
944
945 if (Payload->isA<ErrorList>()) {
946 ErrorList &List = static_cast<ErrorList &>(*Payload);
947 Error R;
948 for (auto &P : List.Payloads)
949 R = ErrorList::join(
950 std::move(R),
951 handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...));
952 return R;
953 }
954
955 return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...);
956}
957
958/// Behaves the same as handleErrors, except that by contract all errors
959/// *must* be handled by the given handlers (i.e. there must be no remaining
960/// errors after running the handlers, or llvm_unreachable is called).
961template <typename... HandlerTs>
962void handleAllErrors(Error E, HandlerTs &&... Handlers) {
963 cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...));
964}
965
966/// Check that E is a non-error, then drop it.
967/// If E is an error, llvm_unreachable will be called.
968inline void handleAllErrors(Error E) {
969 cantFail(std::move(E));
970}
971
972/// Handle any errors (if present) in an Expected<T>, then try a recovery path.
973///
974/// If the incoming value is a success value it is returned unmodified. If it
975/// is a failure value then it the contained error is passed to handleErrors.
976/// If handleErrors is able to handle the error then the RecoveryPath functor
977/// is called to supply the final result. If handleErrors is not able to
978/// handle all errors then the unhandled errors are returned.
979///
980/// This utility enables the follow pattern:
981///
982/// @code{.cpp}
983/// enum FooStrategy { Aggressive, Conservative };
984/// Expected<Foo> foo(FooStrategy S);
985///
986/// auto ResultOrErr =
987/// handleExpected(
988/// foo(Aggressive),
989/// []() { return foo(Conservative); },
990/// [](AggressiveStrategyError&) {
991/// // Implicitly conusme this - we'll recover by using a conservative
992/// // strategy.
993/// });
994///
995/// @endcode
996template <typename T, typename RecoveryFtor, typename... HandlerTs>
997Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath,
998 HandlerTs &&... Handlers) {
999 if (ValOrErr)
1000 return ValOrErr;
1001
1002 if (auto Err = handleErrors(ValOrErr.takeError(),
1003 std::forward<HandlerTs>(Handlers)...))
1004 return std::move(Err);
1005
1006 return RecoveryPath();
1007}
1008
1009/// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner
1010/// will be printed before the first one is logged. A newline will be printed
1011/// after each error.
1012///
1013/// This function is compatible with the helpers from Support/WithColor.h. You
1014/// can pass any of them as the OS. Please consider using them instead of
1015/// including 'error: ' in the ErrorBanner.
1016///
1017/// This is useful in the base level of your program to allow clean termination
1018/// (allowing clean deallocation of resources, etc.), while reporting error
1019/// information to the user.
1020void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {});
1021
1022/// Write all error messages (if any) in E to a string. The newline character
1023/// is used to separate error messages.
1024inline std::string toString(Error E) {
1025 SmallVector<std::string, 2> Errors;
1026 handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
1027 Errors.push_back(EI.message());
1028 });
1029 return join(Errors.begin(), Errors.end(), "\n");
1030}
1031
1032/// Consume a Error without doing anything. This method should be used
1033/// only where an error can be considered a reasonable and expected return
1034/// value.
1035///
1036/// Uses of this method are potentially indicative of design problems: If it's
1037/// legitimate to do nothing while processing an "error", the error-producer
1038/// might be more clearly refactored to return an Optional<T>.
1039inline void consumeError(Error Err) {
1040 handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {});
1041}
1042
1043/// Convert an Expected to an Optional without doing anything. This method
1044/// should be used only where an error can be considered a reasonable and
1045/// expected return value.
1046///
1047/// Uses of this method are potentially indicative of problems: perhaps the
1048/// error should be propagated further, or the error-producer should just
1049/// return an Optional in the first place.
1050template <typename T> Optional<T> expectedToOptional(Expected<T> &&E) {
1051 if (E)
6
←
Taking false branch
→
1052 return std::move(*E);
1053 consumeError(E.takeError());
1054 return None;
7
←
Calling constructor for 'Optional<clang::DirectoryEntryRef>'
→
15
←
Returning from constructor for 'Optional<clang::DirectoryEntryRef>'
→
1055}
1056
1057/// Helper for converting an Error to a bool.
1058///
1059/// This method returns true if Err is in an error state, or false if it is
1060/// in a success state. Puts Err in a checked state in both cases (unlike
1061/// Error::operator bool(), which only does this for success states).
1062inline bool errorToBool(Error Err) {
1063 bool IsError = static_cast<bool>(Err);
1064 if (IsError)
1065 consumeError(std::move(Err));
1066 return IsError;
1067}
1068
1069/// Helper for Errors used as out-parameters.
1070///
1071/// This helper is for use with the Error-as-out-parameter idiom, where an error
1072/// is passed to a function or method by reference, rather than being returned.
1073/// In such cases it is helpful to set the checked bit on entry to the function
1074/// so that the error can be written to (unchecked Errors abort on assignment)
1075/// and clear the checked bit on exit so that clients cannot accidentally forget
1076/// to check the result. This helper performs these actions automatically using
1077/// RAII:
1078///
1079/// @code{.cpp}
1080/// Result foo(Error &Err) {
1081/// ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set
1082/// // <body of foo>
1083/// // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed.
1084/// }
1085/// @endcode
1086///
1087/// ErrorAsOutParameter takes an Error* rather than Error& so that it can be
1088/// used with optional Errors (Error pointers that are allowed to be null). If
1089/// ErrorAsOutParameter took an Error reference, an instance would have to be
1090/// created inside every condition that verified that Error was non-null. By
1091/// taking an Error pointer we can just create one instance at the top of the
1092/// function.
1093class ErrorAsOutParameter {
1094public:
1095 ErrorAsOutParameter(Error *Err) : Err(Err) {
1096 // Raise the checked bit if Err is success.
1097 if (Err)
1098 (void)!!*Err;
1099 }
1100
1101 ~ErrorAsOutParameter() {
1102 // Clear the checked bit.
1103 if (Err && !*Err)
1104 *Err = Error::success();
1105 }
1106
1107private:
1108 Error *Err;
1109};
1110
1111/// Helper for Expected<T>s used as out-parameters.
1112///
1113/// See ErrorAsOutParameter.
1114template <typename T>
1115class ExpectedAsOutParameter {
1116public:
1117 ExpectedAsOutParameter(Expected<T> *ValOrErr)
1118 : ValOrErr(ValOrErr) {
1119 if (ValOrErr)
1120 (void)!!*ValOrErr;
1121 }
1122
1123 ~ExpectedAsOutParameter() {
1124 if (ValOrErr)
1125 ValOrErr->setUnchecked();
1126 }
1127
1128private:
1129 Expected<T> *ValOrErr;
1130};
1131
1132/// This class wraps a std::error_code in a Error.
1133///
1134/// This is useful if you're writing an interface that returns a Error
1135/// (or Expected) and you want to call code that still returns
1136/// std::error_codes.
1137class ECError : public ErrorInfo<ECError> {
1138 friend Error errorCodeToError(std::error_code);
1139
1140 virtual void anchor() override;
1141
1142public:
1143 void setErrorCode(std::error_code EC) { this->EC = EC; }
1144 std::error_code convertToErrorCode() const override { return EC; }
1145 void log(raw_ostream &OS) const override { OS << EC.message(); }
1146
1147 // Used by ErrorInfo::classID.
1148 static char ID;
1149
1150protected:
1151 ECError() = default;
1152 ECError(std::error_code EC) : EC(EC) {}
1153
1154 std::error_code EC;
1155};
1156
1157/// The value returned by this function can be returned from convertToErrorCode
1158/// for Error values where no sensible translation to std::error_code exists.
1159/// It should only be used in this situation, and should never be used where a
1160/// sensible conversion to std::error_code is available, as attempts to convert
1161/// to/from this error will result in a fatal error. (i.e. it is a programmatic
1162///error to try to convert such a value).
1163std::error_code inconvertibleErrorCode();
1164
1165/// Helper for converting an std::error_code to a Error.
1166Error errorCodeToError(std::error_code EC);
1167
1168/// Helper for converting an ECError to a std::error_code.
1169///
1170/// This method requires that Err be Error() or an ECError, otherwise it
1171/// will trigger a call to abort().
1172std::error_code errorToErrorCode(Error Err);
1173
1174/// Convert an ErrorOr<T> to an Expected<T>.
1175template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
1176 if (auto EC = EO.getError())
1177 return errorCodeToError(EC);
1178 return std::move(*EO);
1179}
1180
1181/// Convert an Expected<T> to an ErrorOr<T>.
1182template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
1183 if (auto Err = E.takeError())
1184 return errorToErrorCode(std::move(Err));
1185 return std::move(*E);
1186}
1187
1188/// This class wraps a string in an Error.
1189///
1190/// StringError is useful in cases where the client is not expected to be able
1191/// to consume the specific error message programmatically (for example, if the
1192/// error message is to be presented to the user).
1193///
1194/// StringError can also be used when additional information is to be printed
1195/// along with a error_code message. Depending on the constructor called, this
1196/// class can either display:
1197/// 1. the error_code message (ECError behavior)
1198/// 2. a string
1199/// 3. the error_code message and a string
1200///
1201/// These behaviors are useful when subtyping is required; for example, when a
1202/// specific library needs an explicit error type. In the example below,
1203/// PDBError is derived from StringError:
1204///
1205/// @code{.cpp}
1206/// Expected<int> foo() {
1207/// return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading,
1208/// "Additional information");
1209/// }
1210/// @endcode
1211///
1212class StringError : public ErrorInfo<StringError> {
1213public:
1214 static char ID;
1215
1216 // Prints EC + S and converts to EC
1217 StringError(std::error_code EC, const Twine &S = Twine());
1218
1219 // Prints S and converts to EC
1220 StringError(const Twine &S, std::error_code EC);
1221
1222 void log(raw_ostream &OS) const override;
1223 std::error_code convertToErrorCode() const override;
1224
1225 const std::string &getMessage() const { return Msg; }
1226
1227private:
1228 std::string Msg;
1229 std::error_code EC;
1230 const bool PrintMsgOnly = false;
1231};
1232
1233/// Create formatted StringError object.
1234template <typename... Ts>
1235inline Error createStringError(std::error_code EC, char const *Fmt,
1236 const Ts &... Vals) {
1237 std::string Buffer;
1238 raw_string_ostream Stream(Buffer);
1239 Stream << format(Fmt, Vals...);
1240 return make_error<StringError>(Stream.str(), EC);
1241}
1242
1243Error createStringError(std::error_code EC, char const *Msg);
1244
1245inline Error createStringError(std::error_code EC, const Twine &S) {
1246 return createStringError(EC, S.str().c_str());
1247}
1248
1249template <typename... Ts>
1250inline Error createStringError(std::errc EC, char const *Fmt,
1251 const Ts &... Vals) {
1252 return createStringError(std::make_error_code(EC), Fmt, Vals...);
1253}
1254
1255/// This class wraps a filename and another Error.
1256///
1257/// In some cases, an error needs to live along a 'source' name, in order to
1258/// show more detailed information to the user.
1259class FileError final : public ErrorInfo<FileError> {
1260
1261 friend Error createFileError(const Twine &, Error);
1262 friend Error createFileError(const Twine &, size_t, Error);
1263
1264public:
1265 void log(raw_ostream &OS) const override {
1266 assert(Err && !FileName.empty() && "Trying to log after takeError().")((void)0);
1267 OS << "'" << FileName << "': ";
1268 if (Line.hasValue())
1269 OS << "line " << Line.getValue() << ": ";
1270 Err->log(OS);
1271 }
1272
1273 StringRef getFileName() { return FileName; }
1274
1275 Error takeError() { return Error(std::move(Err)); }
1276
1277 std::error_code convertToErrorCode() const override;
1278
1279 // Used by ErrorInfo::classID.
1280 static char ID;
1281
1282private:
1283 FileError(const Twine &F, Optional<size_t> LineNum,
1284 std::unique_ptr<ErrorInfoBase> E) {
1285 assert(E && "Cannot create FileError from Error success value.")((void)0);
1286 assert(!F.isTriviallyEmpty() &&((void)0)
1287 "The file name provided to FileError must not be empty.")((void)0);
1288 FileName = F.str();
1289 Err = std::move(E);
1290 Line = std::move(LineNum);
1291 }
1292
1293 static Error build(const Twine &F, Optional<size_t> Line, Error E) {
1294 std::unique_ptr<ErrorInfoBase> Payload;
1295 handleAllErrors(std::move(E),
1296 [&](std::unique_ptr<ErrorInfoBase> EIB) -> Error {
1297 Payload = std::move(EIB);
1298 return Error::success();
1299 });
1300 return Error(
1301 std::unique_ptr<FileError>(new FileError(F, Line, std::move(Payload))));
1302 }
1303
1304 std::string FileName;
1305 Optional<size_t> Line;
1306 std::unique_ptr<ErrorInfoBase> Err;
1307};
1308
1309/// Concatenate a source file path and/or name with an Error. The resulting
1310/// Error is unchecked.
1311inline Error createFileError(const Twine &F, Error E) {
1312 return FileError::build(F, Optional<size_t>(), std::move(E));
1313}
1314
1315/// Concatenate a source file path and/or name with line number and an Error.
1316/// The resulting Error is unchecked.
1317inline Error createFileError(const Twine &F, size_t Line, Error E) {
1318 return FileError::build(F, Optional<size_t>(Line), std::move(E));
1319}
1320
1321/// Concatenate a source file path and/or name with a std::error_code
1322/// to form an Error object.
1323inline Error createFileError(const Twine &F, std::error_code EC) {
1324 return createFileError(F, errorCodeToError(EC));
1325}
1326
1327/// Concatenate a source file path and/or name with line number and
1328/// std::error_code to form an Error object.
1329inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) {
1330 return createFileError(F, Line, errorCodeToError(EC));
1331}
1332
1333Error createFileError(const Twine &F, ErrorSuccess) = delete;
1334
1335/// Helper for check-and-exit error handling.
1336///
1337/// For tool use only. NOT FOR USE IN LIBRARY CODE.
1338///
1339class ExitOnError {
1340public:
1341 /// Create an error on exit helper.
1342 ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1)
1343 : Banner(std::move(Banner)),
1344 GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {}
1345
1346 /// Set the banner string for any errors caught by operator().
1347 void setBanner(std::string Banner) { this->Banner = std::move(Banner); }
1348
1349 /// Set the exit-code mapper function.
1350 void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) {
1351 this->GetExitCode = std::move(GetExitCode);
1352 }
1353
1354 /// Check Err. If it's in a failure state log the error(s) and exit.
1355 void operator()(Error Err) const { checkError(std::move(Err)); }
1356
1357 /// Check E. If it's in a success state then return the contained value. If
1358 /// it's in a failure state log the error(s) and exit.
1359 template <typename T> T operator()(Expected<T> &&E) const {
1360 checkError(E.takeError());
1361 return std::move(*E);
1362 }
1363
1364 /// Check E. If it's in a success state then return the contained reference. If
1365 /// it's in a failure state log the error(s) and exit.
1366 template <typename T> T& operator()(Expected<T&> &&E) const {
1367 checkError(E.takeError());
1368 return *E;
1369 }
1370
1371private:
1372 void checkError(Error Err) const {
1373 if (Err) {
1374 int ExitCode = GetExitCode(Err);
1375 logAllUnhandledErrors(std::move(Err), errs(), Banner);
1376 exit(ExitCode);
1377 }
1378 }
1379
1380 std::string Banner;
1381 std::function<int(const Error &)> GetExitCode;
1382};
1383
1384/// Conversion from Error to LLVMErrorRef for C error bindings.
1385inline LLVMErrorRef wrap(Error Err) {
1386 return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release());
1387}
1388
1389/// Conversion from LLVMErrorRef to Error for C error bindings.
1390inline Error unwrap(LLVMErrorRef ErrRef) {
1391 return Error(std::unique_ptr<ErrorInfoBase>(
1392 reinterpret_cast<ErrorInfoBase *>(ErrRef)));
1393}
1394
1395} // end namespace llvm
1396
1397#endif // LLVM_SUPPORT_ERROR_H
←

/usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/llvm/include/llvm/ADT/Optional.h

→
1//===- Optional.h - Simple variant for passing optional values --*- C++ -*-===//
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// This file provides Optional, a template class modeled in the spirit of
10// OCaml's 'opt' variant. The idea is to strongly type whether or not
11// a value can be optional.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_ADT_OPTIONAL_H
16#define LLVM_ADT_OPTIONAL_H
17
18#include "llvm/ADT/Hashing.h"
19#include "llvm/ADT/None.h"
20#include "llvm/ADT/STLForwardCompat.h"
21#include "llvm/Support/Compiler.h"
22#include "llvm/Support/type_traits.h"
23#include <cassert>
24#include <memory>
25#include <new>
26#include <utility>
27
28namespace llvm {
29
30class raw_ostream;
31
32namespace optional_detail {
33
34/// Storage for any type.
35//
36// The specialization condition intentionally uses
37// llvm::is_trivially_copy_constructible instead of
38// std::is_trivially_copy_constructible. GCC versions prior to 7.4 may
39// instantiate the copy constructor of `T` when
40// std::is_trivially_copy_constructible is instantiated. This causes
41// compilation to fail if we query the trivially copy constructible property of
42// a class which is not copy constructible.
43//
44// The current implementation of OptionalStorage insists that in order to use
45// the trivial specialization, the value_type must be trivially copy
46// constructible and trivially copy assignable due to =default implementations
47// of the copy/move constructor/assignment. It does not follow that this is
48// necessarily the case std::is_trivially_copyable is true (hence the expanded
49// specialization condition).
50//
51// The move constructible / assignable conditions emulate the remaining behavior
52// of std::is_trivially_copyable.
53template <typename T, bool = (llvm::is_trivially_copy_constructible<T>::value &&
54 std::is_trivially_copy_assignable<T>::value &&
55 (std::is_trivially_move_constructible<T>::value ||
56 !std::is_move_constructible<T>::value) &&
57 (std::is_trivially_move_assignable<T>::value ||
58 !std::is_move_assignable<T>::value))>
59class OptionalStorage {
60 union {
61 char empty;
62 T value;
63 };
64 bool hasVal;
65
66public:
67 ~OptionalStorage() { reset(); }
68
69 constexpr OptionalStorage() noexcept : empty(), hasVal(false) {}
70
71 constexpr OptionalStorage(OptionalStorage const &other) : OptionalStorage() {
72 if (other.hasValue()) {
73 emplace(other.value);
74 }
75 }
76 constexpr OptionalStorage(OptionalStorage &&other) : OptionalStorage() {
77 if (other.hasValue()) {
78 emplace(std::move(other.value));
79 }
80 }
81
82 template <class... Args>
83 constexpr explicit OptionalStorage(in_place_t, Args &&... args)
84 : value(std::forward<Args>(args)...), hasVal(true) {}
85
86 void reset() noexcept {
87 if (hasVal) {
88 value.~T();
89 hasVal = false;
90 }
91 }
92
93 constexpr bool hasValue() const noexcept { return hasVal; }
94
95 T &getValue() LLVM_LVALUE_FUNCTION& noexcept {
96 assert(hasVal)((void)0);
97 return value;
98 }
99 constexpr T const &getValue() const LLVM_LVALUE_FUNCTION& noexcept {
100 assert(hasVal)((void)0);
101 return value;
102 }
103#if LLVM_HAS_RVALUE_REFERENCE_THIS1
104 T &&getValue() && noexcept {
105 assert(hasVal)((void)0);
106 return std::move(value);
107 }
108#endif
109
110 template <class... Args> void emplace(Args &&... args) {
111 reset();
112 ::new ((void *)std::addressof(value)) T(std::forward<Args>(args)...);
113 hasVal = true;
114 }
115
116 OptionalStorage &operator=(T const &y) {
117 if (hasValue()) {
118 value = y;
119 } else {
120 ::new ((void *)std::addressof(value)) T(y);
121 hasVal = true;
122 }
123 return *this;
124 }
125 OptionalStorage &operator=(T &&y) {
126 if (hasValue()) {
127 value = std::move(y);
128 } else {
129 ::new ((void *)std::addressof(value)) T(std::move(y));
130 hasVal = true;
131 }
132 return *this;
133 }
134
135 OptionalStorage &operator=(OptionalStorage const &other) {
136 if (other.hasValue()) {
137 if (hasValue()) {
138 value = other.value;
139 } else {
140 ::new ((void *)std::addressof(value)) T(other.value);
141 hasVal = true;
142 }
143 } else {
144 reset();
145 }
146 return *this;
147 }
148
149 OptionalStorage &operator=(OptionalStorage &&other) {
150 if (other.hasValue()) {
151 if (hasValue()) {
152 value = std::move(other.value);
153 } else {
154 ::new ((void *)std::addressof(value)) T(std::move(other.value));
155 hasVal = true;
156 }
157 } else {
158 reset();
159 }
160 return *this;
161 }
162};
163
164template <typename T> class OptionalStorage<T, true> {
165 union {
166 char empty;
167 T value;
168 };
169 bool hasVal = false;
170
171public:
172 ~OptionalStorage() = default;
173
174 constexpr OptionalStorage() noexcept : empty{} {}
175
176 constexpr OptionalStorage(OptionalStorage const &other) = default;
177 constexpr OptionalStorage(OptionalStorage &&other) = default;
178
179 OptionalStorage &operator=(OptionalStorage const &other) = default;
180 OptionalStorage &operator=(OptionalStorage &&other) = default;
181
182 template <class... Args>
183 constexpr explicit OptionalStorage(in_place_t, Args &&... args)
184 : value(std::forward<Args>(args)...), hasVal(true) {}
185
186 void reset() noexcept {
187 if (hasVal) {
188 value.~T();
189 hasVal = false;
190 }
191 }
192
193 constexpr bool hasValue() const noexcept { return hasVal; }
194
195 T &getValue() LLVM_LVALUE_FUNCTION& noexcept {
196 assert(hasVal)((void)0);
197 return value;
198 }
199 constexpr T const &getValue() const LLVM_LVALUE_FUNCTION& noexcept {
200 assert(hasVal)((void)0);
201 return value;
202 }
203#if LLVM_HAS_RVALUE_REFERENCE_THIS1
204 T &&getValue() && noexcept {
205 assert(hasVal)((void)0);
206 return std::move(value);
207 }
208#endif
209
210 template <class... Args> void emplace(Args &&... args) {
211 reset();
212 ::new ((void *)std::addressof(value)) T(std::forward<Args>(args)...);
213 hasVal = true;
214 }
215
216 OptionalStorage &operator=(T const &y) {
217 if (hasValue()) {
218 value = y;
219 } else {
220 ::new ((void *)std::addressof(value)) T(y);
221 hasVal = true;
222 }
223 return *this;
224 }
225 OptionalStorage &operator=(T &&y) {
226 if (hasValue()) {
227 value = std::move(y);
228 } else {
229 ::new ((void *)std::addressof(value)) T(std::move(y));
230 hasVal = true;
231 }
232 return *this;
233 }
234};
235
236} // namespace optional_detail
237
238template <typename T> class Optional {
239 optional_detail::OptionalStorage<T> Storage;
240
241public:
242 using value_type = T;
243
244 constexpr Optional() {}
245 constexpr Optional(NoneType) {}
8
←
Calling defaulted default constructor for 'OptionalStorage<clang::DirectoryEntryRef, true>'
→
14
←
Returning from default constructor for 'OptionalStorage<clang::DirectoryEntryRef, true>'
→
246
247 constexpr Optional(const T &y) : Storage(in_place, y) {}
248 constexpr Optional(const Optional &O) = default;
249
250 constexpr Optional(T &&y) : Storage(in_place, std::move(y)) {}
251 constexpr Optional(Optional &&O) = default;
252
253 template <typename... ArgTypes>
254 constexpr Optional(in_place_t, ArgTypes &&...Args)
255 : Storage(in_place, std::forward<ArgTypes>(Args)...) {}
256
257 Optional &operator=(T &&y) {
258 Storage = std::move(y);
259 return *this;
260 }
261 Optional &operator=(Optional &&O) = default;
262
263 /// Create a new object by constructing it in place with the given arguments.
264 template <typename... ArgTypes> void emplace(ArgTypes &&... Args) {
265 Storage.emplace(std::forward<ArgTypes>(Args)...);
266 }
267
268 static constexpr Optional create(const T *y) {
269 return y ? Optional(*y) : Optional();
270 }
271
272 Optional &operator=(const T &y) {
273 Storage = y;
274 return *this;
275 }
276 Optional &operator=(const Optional &O) = default;
277
278 void reset() { Storage.reset(); }
279
280 constexpr const T *getPointer() const { return &Storage.getValue(); }
281 T *getPointer() { return &Storage.getValue(); }
282 constexpr const T &getValue() const LLVM_LVALUE_FUNCTION& {
283 return Storage.getValue();
284 }
285 T &getValue() LLVM_LVALUE_FUNCTION& { return Storage.getValue(); }
286
287 constexpr explicit operator bool() const { return hasValue(); }
288 constexpr bool hasValue() const { return Storage.hasValue(); }
289 constexpr const T *operator->() const { return getPointer(); }
290 T *operator->() { return getPointer(); }
291 constexpr const T &operator*() const LLVM_LVALUE_FUNCTION& {
292 return getValue();
293 }
294 T &operator*() LLVM_LVALUE_FUNCTION& { return getValue(); }
295
296 template <typename U>
297 constexpr T getValueOr(U &&value) const LLVM_LVALUE_FUNCTION& {
298 return hasValue() ? getValue() : std::forward<U>(value);
299 }
300
301 /// Apply a function to the value if present; otherwise return None.
302 template <class Function>
303 auto map(const Function &F) const LLVM_LVALUE_FUNCTION&
304 -> Optional<decltype(F(getValue()))> {
305 if (*this) return F(getValue());
306 return None;
307 }
308
309#if LLVM_HAS_RVALUE_REFERENCE_THIS1
310 T &&getValue() && { return std::move(Storage.getValue()); }
311 T &&operator*() && { return std::move(Storage.getValue()); }
312
313 template <typename U>
314 T getValueOr(U &&value) && {
315 return hasValue() ? std::move(getValue()) : std::forward<U>(value);
316 }
317
318 /// Apply a function to the value if present; otherwise return None.
319 template <class Function>
320 auto map(const Function &F) &&
321 -> Optional<decltype(F(std::move(*this).getValue()))> {
322 if (*this) return F(std::move(*this).getValue());
323 return None;
324 }
325#endif
326};
327
328template <class T> llvm::hash_code hash_value(const Optional<T> &O) {
329 return O ? hash_combine(true, *O) : hash_value(false);
330}
331
332template <typename T, typename U>
333constexpr bool operator==(const Optional<T> &X, const Optional<U> &Y) {
334 if (X && Y)
335 return *X == *Y;
336 return X.hasValue() == Y.hasValue();
337}
338
339template <typename T, typename U>
340constexpr bool operator!=(const Optional<T> &X, const Optional<U> &Y) {
341 return !(X == Y);
342}
343
344template <typename T, typename U>
345constexpr bool operator<(const Optional<T> &X, const Optional<U> &Y) {
346 if (X && Y)
347 return *X < *Y;
348 return X.hasValue() < Y.hasValue();
349}
350
351template <typename T, typename U>
352constexpr bool operator<=(const Optional<T> &X, const Optional<U> &Y) {
353 return !(Y < X);
354}
355
356template <typename T, typename U>
357constexpr bool operator>(const Optional<T> &X, const Optional<U> &Y) {
358 return Y < X;
359}
360
361template <typename T, typename U>
362constexpr bool operator>=(const Optional<T> &X, const Optional<U> &Y) {
363 return !(X < Y);
364}
365
366template <typename T>
367constexpr bool operator==(const Optional<T> &X, NoneType) {
368 return !X;
369}
370
371template <typename T>
372constexpr bool operator==(NoneType, const Optional<T> &X) {
373 return X == None;
374}
375
376template <typename T>
377constexpr bool operator!=(const Optional<T> &X, NoneType) {
378 return !(X == None);
379}
380
381template <typename T>
382constexpr bool operator!=(NoneType, const Optional<T> &X) {
383 return X != None;
384}
385
386template <typename T> constexpr bool operator<(const Optional<T> &, NoneType) {
387 return false;
388}
389
390template <typename T> constexpr bool operator<(NoneType, const Optional<T> &X) {
391 return X.hasValue();
392}
393
394template <typename T>
395constexpr bool operator<=(const Optional<T> &X, NoneType) {
396 return !(None < X);
397}
398
399template <typename T>
400constexpr bool operator<=(NoneType, const Optional<T> &X) {
401 return !(X < None);
402}
403
404template <typename T> constexpr bool operator>(const Optional<T> &X, NoneType) {
405 return None < X;
406}
407
408template <typename T> constexpr bool operator>(NoneType, const Optional<T> &X) {
409 return X < None;
410}
411
412template <typename T>
413constexpr bool operator>=(const Optional<T> &X, NoneType) {
414 return None <= X;
415}
416
417template <typename T>
418constexpr bool operator>=(NoneType, const Optional<T> &X) {
419 return X <= None;
420}
421
422template <typename T>
423constexpr bool operator==(const Optional<T> &X, const T &Y) {
424 return X && *X == Y;
425}
426
427template <typename T>
428constexpr bool operator==(const T &X, const Optional<T> &Y) {
429 return Y && X == *Y;
430}
431
432template <typename T>
433constexpr bool operator!=(const Optional<T> &X, const T &Y) {
434 return !(X == Y);
435}
436
437template <typename T>
438constexpr bool operator!=(const T &X, const Optional<T> &Y) {
439 return !(X == Y);
440}
441
442template <typename T>
443constexpr bool operator<(const Optional<T> &X, const T &Y) {
444 return !X || *X < Y;
445}
446
447template <typename T>
448constexpr bool operator<(const T &X, const Optional<T> &Y) {
449 return Y && X < *Y;
450}
451
452template <typename T>
453constexpr bool operator<=(const Optional<T> &X, const T &Y) {
454 return !(Y < X);
455}
456
457template <typename T>
458constexpr bool operator<=(const T &X, const Optional<T> &Y) {
459 return !(Y < X);
460}
461
462template <typename T>
463constexpr bool operator>(const Optional<T> &X, const T &Y) {
464 return Y < X;
465}
466
467template <typename T>
468constexpr bool operator>(const T &X, const Optional<T> &Y) {
469 return Y < X;
470}
471
472template <typename T>
473constexpr bool operator>=(const Optional<T> &X, const T &Y) {
474 return !(X < Y);
475}
476
477template <typename T>
478constexpr bool operator>=(const T &X, const Optional<T> &Y) {
479 return !(X < Y);
480}
481
482raw_ostream &operator<<(raw_ostream &OS, NoneType);
483
484template <typename T, typename = decltype(std::declval<raw_ostream &>()
485 << std::declval<const T &>())>
486raw_ostream &operator<<(raw_ostream &OS, const Optional<T> &O) {
487 if (O)
488 OS << *O;
489 else
490 OS << None;
491 return OS;
492}
493
494} // end namespace llvm
495
496#endif // LLVM_ADT_OPTIONAL_H
←

/usr/src/gnu/usr.bin/clang/libclangBasic/../../../llvm/clang/include/clang/Basic/DirectoryEntry.h

1//===- clang/Basic/DirectoryEntry.h - Directory references ------*- C++ -*-===//
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/// \file
10/// Defines interfaces for clang::DirectoryEntry and clang::DirectoryEntryRef.
11///
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_BASIC_DIRECTORYENTRY_H
15#define LLVM_CLANG_BASIC_DIRECTORYENTRY_H
16
17#include "clang/Basic/LLVM.h"
18#include "llvm/ADT/DenseMapInfo.h"
19#include "llvm/ADT/Hashing.h"
20#include "llvm/ADT/StringMap.h"
21#include "llvm/ADT/StringRef.h"
22#include "llvm/Support/ErrorOr.h"
23
24namespace clang {
25namespace FileMgr {
26
27template <class RefTy> class MapEntryOptionalStorage;
28
29} // end namespace FileMgr
30
31/// Cached information about one directory (either on disk or in
32/// the virtual file system).
33class DirectoryEntry {
34 friend class FileManager;
35
36 // FIXME: We should not be storing a directory entry name here.
37 StringRef Name; // Name of the directory.
38
39public:
40 StringRef getName() const { return Name; }
41};
42
43/// A reference to a \c DirectoryEntry that includes the name of the directory
44/// as it was accessed by the FileManager's client.
45class DirectoryEntryRef {
46public:
47 const DirectoryEntry &getDirEntry() const { return *ME->getValue(); }
19
←
Called C++ object pointer is null
48
49 StringRef getName() const { return ME->getKey(); }
50
51 /// Hash code is based on the DirectoryEntry, not the specific named
52 /// reference.
53 friend llvm::hash_code hash_value(DirectoryEntryRef Ref) {
54 return llvm::hash_value(&Ref.getDirEntry());
55 }
56
57 using MapEntry = llvm::StringMapEntry<llvm::ErrorOr<DirectoryEntry &>>;
58
59 const MapEntry &getMapEntry() const { return *ME; }
60
61 /// Check if RHS referenced the file in exactly the same way.
62 bool isSameRef(DirectoryEntryRef RHS) const { return ME == RHS.ME; }
63
64 DirectoryEntryRef() = delete;
65 DirectoryEntryRef(const MapEntry &ME) : ME(&ME) {}
66
67 /// Allow DirectoryEntryRef to degrade into 'const DirectoryEntry*' to
68 /// facilitate incremental adoption.
69 ///
70 /// The goal is to avoid code churn due to dances like the following:
71 /// \code
72 /// // Old code.
73 /// lvalue = rvalue;
74 ///
75 /// // Temporary code from an incremental patch.
76 /// lvalue = &rvalue.getDirectoryEntry();
77 ///
78 /// // Final code.
79 /// lvalue = rvalue;
80 /// \endcode
81 ///
82 /// FIXME: Once DirectoryEntryRef is "everywhere" and DirectoryEntry::getName
83 /// has been deleted, delete this implicit conversion.
84 operator const DirectoryEntry *() const { return &getDirEntry(); }
85
86private:
87 friend class FileMgr::MapEntryOptionalStorage<DirectoryEntryRef>;
88 struct optional_none_tag {};
89
90 // Private constructor for use by OptionalStorage.
91 DirectoryEntryRef(optional_none_tag) : ME(nullptr) {}
11
←
Null pointer value stored to 'DirInfo.Storage.MaybeRef.ME'
→
92 bool hasOptionalValue() const { return ME; }
93
94 friend struct llvm::DenseMapInfo<DirectoryEntryRef>;
95 struct dense_map_empty_tag {};
96 struct dense_map_tombstone_tag {};
97
98 // Private constructors for use by DenseMapInfo.
99 DirectoryEntryRef(dense_map_empty_tag)
100 : ME(llvm::DenseMapInfo<const MapEntry *>::getEmptyKey()) {}
101 DirectoryEntryRef(dense_map_tombstone_tag)
102 : ME(llvm::DenseMapInfo<const MapEntry *>::getTombstoneKey()) {}
103 bool isSpecialDenseMapKey() const {
104 return isSameRef(DirectoryEntryRef(dense_map_empty_tag())) ||
105 isSameRef(DirectoryEntryRef(dense_map_tombstone_tag()));
106 }
107
108 const MapEntry *ME;
109};
110
111namespace FileMgr {
112
113/// Customized storage for refs derived from map entires in FileManager, using
114/// the private optional_none_tag to keep it to the size of a single pointer.
115template <class RefTy> class MapEntryOptionalStorage {
116 using optional_none_tag = typename RefTy::optional_none_tag;
117 RefTy MaybeRef;
118
119public:
120 MapEntryOptionalStorage() : MaybeRef(optional_none_tag()) {}
10
←
Calling constructor for 'DirectoryEntryRef'
→
12
←
Returning from constructor for 'DirectoryEntryRef'
→
121
122 template <class... ArgTypes>
123 explicit MapEntryOptionalStorage(llvm::in_place_t, ArgTypes &&...Args)
124 : MaybeRef(std::forward<ArgTypes>(Args)...) {}
125
126 void reset() { MaybeRef = optional_none_tag(); }
127
128 bool hasValue() const { return MaybeRef.hasOptionalValue(); }
129
130 RefTy &getValue() LLVM_LVALUE_FUNCTION& {
131 assert(hasValue())((void)0);
132 return MaybeRef;
133 }
134 RefTy const &getValue() const LLVM_LVALUE_FUNCTION& {
135 assert(hasValue())((void)0);
136 return MaybeRef;
137 }
138#if LLVM_HAS_RVALUE_REFERENCE_THIS1
139 RefTy &&getValue() && {
140 assert(hasValue())((void)0);
141 return std::move(MaybeRef);
142 }
143#endif
144
145 template <class... Args> void emplace(Args &&...args) {
146 MaybeRef = RefTy(std::forward<Args>(args)...);
147 }
148
149 MapEntryOptionalStorage &operator=(RefTy Ref) {
150 MaybeRef = Ref;
151 return *this;
152 }
153};
154
155} // end namespace FileMgr
156} // end namespace clang
157
158namespace llvm {
159namespace optional_detail {
160
161/// Customize OptionalStorage<DirectoryEntryRef> to use DirectoryEntryRef and
162/// its optional_none_tag to keep it the size of a single pointer.
163template <>
164class OptionalStorage<clang::DirectoryEntryRef>
165 : public clang::FileMgr::MapEntryOptionalStorage<clang::DirectoryEntryRef> {
166 using StorageImpl =
167 clang::FileMgr::MapEntryOptionalStorage<clang::DirectoryEntryRef>;
168
169public:
170 OptionalStorage() = default;
9
←
Calling default constructor for 'MapEntryOptionalStorage<clang::DirectoryEntryRef>'
→
13
←
Returning from default constructor for 'MapEntryOptionalStorage<clang::DirectoryEntryRef>'
→
171
172 template <class... ArgTypes>
173 explicit OptionalStorage(in_place_t, ArgTypes &&...Args)
174 : StorageImpl(in_place_t{}, std::forward<ArgTypes>(Args)...) {}
175
176 OptionalStorage &operator=(clang::DirectoryEntryRef Ref) {
177 StorageImpl::operator=(Ref);
178 return *this;
179 }
180};
181
182static_assert(sizeof(Optional<clang::DirectoryEntryRef>) ==
183 sizeof(clang::DirectoryEntryRef),
184 "Optional<DirectoryEntryRef> must avoid size overhead");
185
186static_assert(
187 std::is_trivially_copyable<Optional<clang::DirectoryEntryRef>>::value,
188 "Optional<DirectoryEntryRef> should be trivially copyable");
189
190} // end namespace optional_detail
191
192/// Specialisation of DenseMapInfo for DirectoryEntryRef.
193template <> struct DenseMapInfo<clang::DirectoryEntryRef> {
194 static inline clang::DirectoryEntryRef getEmptyKey() {
195 return clang::DirectoryEntryRef(
196 clang::DirectoryEntryRef::dense_map_empty_tag());
197 }
198
199 static inline clang::DirectoryEntryRef getTombstoneKey() {
200 return clang::DirectoryEntryRef(
201 clang::DirectoryEntryRef::dense_map_tombstone_tag());
202 }
203
204 static unsigned getHashValue(clang::DirectoryEntryRef Val) {
205 return hash_value(Val);
206 }
207
208 static bool isEqual(clang::DirectoryEntryRef LHS,
209 clang::DirectoryEntryRef RHS) {
210 // Catch the easy cases: both empty, both tombstone, or the same ref.
211 if (LHS.isSameRef(RHS))
212 return true;
213
214 // Confirm LHS and RHS are valid.
215 if (LHS.isSpecialDenseMapKey() || RHS.isSpecialDenseMapKey())
216 return false;
217
218 // It's safe to use operator==.
219 return LHS == RHS;
220 }
221};
222
223} // end namespace llvm
224
225namespace clang {
226
227/// Wrapper around Optional<DirectoryEntryRef> that degrades to 'const
228/// DirectoryEntry*', facilitating incremental patches to propagate
229/// DirectoryEntryRef.
230///
231/// This class can be used as return value or field where it's convenient for
232/// an Optional<DirectoryEntryRef> to degrade to a 'const DirectoryEntry*'. The
233/// purpose is to avoid code churn due to dances like the following:
234/// \code
235/// // Old code.
236/// lvalue = rvalue;
237///
238/// // Temporary code from an incremental patch.
239/// Optional<DirectoryEntryRef> MaybeF = rvalue;
240/// lvalue = MaybeF ? &MaybeF.getDirectoryEntry() : nullptr;
241///
242/// // Final code.
243/// lvalue = rvalue;
244/// \endcode
245///
246/// FIXME: Once DirectoryEntryRef is "everywhere" and DirectoryEntry::LastRef
247/// and DirectoryEntry::getName have been deleted, delete this class and
248/// replace instances with Optional<DirectoryEntryRef>.
249class OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr
250 : public Optional<DirectoryEntryRef> {
251public:
252 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr() = default;
253 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr(
254 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &&) = default;
255 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr(
256 const OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &) = default;
257 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &
258 operator=(OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &&) = default;
259 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &
260 operator=(const OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &) = default;
261
262 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr(llvm::NoneType) {}
263 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr(DirectoryEntryRef Ref)
264 : Optional<DirectoryEntryRef>(Ref) {}
265 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr(Optional<DirectoryEntryRef> MaybeRef)
266 : Optional<DirectoryEntryRef>(MaybeRef) {}
267
268 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &operator=(llvm::NoneType) {
269 Optional<DirectoryEntryRef>::operator=(None);
270 return *this;
271 }
272 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &operator=(DirectoryEntryRef Ref) {
273 Optional<DirectoryEntryRef>::operator=(Ref);
274 return *this;
275 }
276 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr &
277 operator=(Optional<DirectoryEntryRef> MaybeRef) {
278 Optional<DirectoryEntryRef>::operator=(MaybeRef);
279 return *this;
280 }
281
282 /// Degrade to 'const DirectoryEntry *' to allow DirectoryEntry::LastRef and
283 /// DirectoryEntry::getName have been deleted, delete this class and replace
284 /// instances with Optional<DirectoryEntryRef>
285 operator const DirectoryEntry *() const {
286 return hasValue() ? &getValue().getDirEntry() : nullptr;
287 }
288};
289
290static_assert(std::is_trivially_copyable<
291 OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr>::value,
292 "OptionalDirectoryEntryRefDegradesToDirectoryEntryPtr should be "
293 "trivially copyable");
294
295} // end namespace clang
296
297#endif // LLVM_CLANG_BASIC_DIRECTORYENTRY_H