Bug Summary

File:src/gnu/usr.bin/clang/libclangFrontend/../../../llvm/llvm/include/llvm/Bitstream/BitstreamReader.h
Warning:line 221, column 39
The result of the right shift is undefined due to shifting by '64', which is greater or equal to the width of type 'llvm::SimpleBitstreamCursor::word_t'

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 SerializedDiagnosticReader.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/libclangFrontend/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangFrontend/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangFrontend/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangFrontend/../include -I /usr/src/gnu/usr.bin/clang/libclangFrontend/obj -I /usr/src/gnu/usr.bin/clang/libclangFrontend/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/libclangFrontend/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/libclangFrontend/../../../llvm/clang/lib/Frontend/SerializedDiagnosticReader.cpp

/usr/src/gnu/usr.bin/clang/libclangFrontend/../../../llvm/clang/lib/Frontend/SerializedDiagnosticReader.cpp

→
1//===- SerializedDiagnosticReader.cpp - Reads diagnostics -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "clang/Frontend/SerializedDiagnosticReader.h"
10#include "clang/Basic/FileManager.h"
11#include "clang/Basic/FileSystemOptions.h"
12#include "clang/Frontend/SerializedDiagnostics.h"
13#include "llvm/ADT/Optional.h"
14#include "llvm/ADT/SmallVector.h"
15#include "llvm/ADT/StringRef.h"
16#include "llvm/Bitstream/BitCodes.h"
17#include "llvm/Bitstream/BitstreamReader.h"
18#include "llvm/Support/Compiler.h"
19#include "llvm/Support/ErrorHandling.h"
20#include "llvm/Support/ErrorOr.h"
21#include "llvm/Support/ManagedStatic.h"
22#include <cstdint>
23#include <system_error>
24
25using namespace clang;
26using namespace serialized_diags;
27
28std::error_code SerializedDiagnosticReader::readDiagnostics(StringRef File) {
29 // Open the diagnostics file.
30 FileSystemOptions FO;
31 FileManager FileMgr(FO);
32
33 auto Buffer = FileMgr.getBufferForFile(File);
34 if (!Buffer)
1
Taking false branch
→
35 return SDError::CouldNotLoad;
36
37 llvm::BitstreamCursor Stream(**Buffer);
38 Optional<llvm::BitstreamBlockInfo> BlockInfo;
39
40 if (Stream.AtEndOfStream())
2
←
Taking false branch
→
41 return SDError::InvalidSignature;
42
43 // Sniff for the signature.
44 for (unsigned char C : {'D', 'I', 'A', 'G'}) {
3
←
Assuming '__begin1' is not equal to '__end1'
→
45 if (Expected<llvm::SimpleBitstreamCursor::word_t> Res = Stream.Read(8)) {
4
←
Calling 'SimpleBitstreamCursor::Read'
→
46 if (Res.get() == C)
47 continue;
48 } else {
49 // FIXME this drops the error on the floor.
50 consumeError(Res.takeError());
51 }
52 return SDError::InvalidSignature;
53 }
54
55 // Read the top level blocks.
56 while (!Stream.AtEndOfStream()) {
57 if (Expected<unsigned> Res = Stream.ReadCode()) {
58 if (Res.get() != llvm::bitc::ENTER_SUBBLOCK)
59 return SDError::InvalidDiagnostics;
60 } else {
61 // FIXME this drops the error on the floor.
62 consumeError(Res.takeError());
63 return SDError::InvalidDiagnostics;
64 }
65
66 std::error_code EC;
67 Expected<unsigned> MaybeSubBlockID = Stream.ReadSubBlockID();
68 if (!MaybeSubBlockID) {
69 // FIXME this drops the error on the floor.
70 consumeError(MaybeSubBlockID.takeError());
71 return SDError::InvalidDiagnostics;
72 }
73
74 switch (MaybeSubBlockID.get()) {
75 case llvm::bitc::BLOCKINFO_BLOCK_ID: {
76 Expected<Optional<llvm::BitstreamBlockInfo>> MaybeBlockInfo =
77 Stream.ReadBlockInfoBlock();
78 if (!MaybeBlockInfo) {
79 // FIXME this drops the error on the floor.
80 consumeError(MaybeBlockInfo.takeError());
81 return SDError::InvalidDiagnostics;
82 }
83 BlockInfo = std::move(MaybeBlockInfo.get());
84 }
85 if (!BlockInfo)
86 return SDError::MalformedBlockInfoBlock;
87 Stream.setBlockInfo(&*BlockInfo);
88 continue;
89 case BLOCK_META:
90 if ((EC = readMetaBlock(Stream)))
91 return EC;
92 continue;
93 case BLOCK_DIAG:
94 if ((EC = readDiagnosticBlock(Stream)))
95 return EC;
96 continue;
97 default:
98 if (llvm::Error Err = Stream.SkipBlock()) {
99 // FIXME this drops the error on the floor.
100 consumeError(std::move(Err));
101 return SDError::MalformedTopLevelBlock;
102 }
103 continue;
104 }
105 }
106 return {};
107}
108
109enum class SerializedDiagnosticReader::Cursor {
110 Record = 1,
111 BlockEnd,
112 BlockBegin
113};
114
115llvm::ErrorOr<SerializedDiagnosticReader::Cursor>
116SerializedDiagnosticReader::skipUntilRecordOrBlock(
117 llvm::BitstreamCursor &Stream, unsigned &BlockOrRecordID) {
118 BlockOrRecordID = 0;
119
120 while (!Stream.AtEndOfStream()) {
121 unsigned Code;
122 if (Expected<unsigned> Res = Stream.ReadCode())
123 Code = Res.get();
124 else
125 return llvm::errorToErrorCode(Res.takeError());
126
127 if (Code >= static_cast<unsigned>(llvm::bitc::FIRST_APPLICATION_ABBREV)) {
128 // We found a record.
129 BlockOrRecordID = Code;
130 return Cursor::Record;
131 }
132 switch (static_cast<llvm::bitc::FixedAbbrevIDs>(Code)) {
133 case llvm::bitc::ENTER_SUBBLOCK:
134 if (Expected<unsigned> Res = Stream.ReadSubBlockID())
135 BlockOrRecordID = Res.get();
136 else
137 return llvm::errorToErrorCode(Res.takeError());
138 return Cursor::BlockBegin;
139
140 case llvm::bitc::END_BLOCK:
141 if (Stream.ReadBlockEnd())
142 return SDError::InvalidDiagnostics;
143 return Cursor::BlockEnd;
144
145 case llvm::bitc::DEFINE_ABBREV:
146 if (llvm::Error Err = Stream.ReadAbbrevRecord())
147 return llvm::errorToErrorCode(std::move(Err));
148 continue;
149
150 case llvm::bitc::UNABBREV_RECORD:
151 return SDError::UnsupportedConstruct;
152
153 case llvm::bitc::FIRST_APPLICATION_ABBREV:
154 llvm_unreachable("Unexpected abbrev id.")__builtin_unreachable();
155 }
156 }
157
158 return SDError::InvalidDiagnostics;
159}
160
161std::error_code
162SerializedDiagnosticReader::readMetaBlock(llvm::BitstreamCursor &Stream) {
163 if (llvm::Error Err =
164 Stream.EnterSubBlock(clang::serialized_diags::BLOCK_META)) {
165 // FIXME this drops the error on the floor.
166 consumeError(std::move(Err));
167 return SDError::MalformedMetadataBlock;
168 }
169
170 bool VersionChecked = false;
171
172 while (true) {
173 unsigned BlockOrCode = 0;
174 llvm::ErrorOr<Cursor> Res = skipUntilRecordOrBlock(Stream, BlockOrCode);
175 if (!Res)
176 Res.getError();
177
178 switch (Res.get()) {
179 case Cursor::Record:
180 break;
181 case Cursor::BlockBegin:
182 if (llvm::Error Err = Stream.SkipBlock()) {
183 // FIXME this drops the error on the floor.
184 consumeError(std::move(Err));
185 return SDError::MalformedMetadataBlock;
186 }
187 LLVM_FALLTHROUGH[[gnu::fallthrough]];
188 case Cursor::BlockEnd:
189 if (!VersionChecked)
190 return SDError::MissingVersion;
191 return {};
192 }
193
194 SmallVector<uint64_t, 1> Record;
195 Expected<unsigned> MaybeRecordID = Stream.readRecord(BlockOrCode, Record);
196 if (!MaybeRecordID)
197 return errorToErrorCode(MaybeRecordID.takeError());
198 unsigned RecordID = MaybeRecordID.get();
199
200 if (RecordID == RECORD_VERSION) {
201 if (Record.size() < 1)
202 return SDError::MissingVersion;
203 if (Record[0] > VersionNumber)
204 return SDError::VersionMismatch;
205 VersionChecked = true;
206 }
207 }
208}
209
210std::error_code
211SerializedDiagnosticReader::readDiagnosticBlock(llvm::BitstreamCursor &Stream) {
212 if (llvm::Error Err =
213 Stream.EnterSubBlock(clang::serialized_diags::BLOCK_DIAG)) {
214 // FIXME this drops the error on the floor.
215 consumeError(std::move(Err));
216 return SDError::MalformedDiagnosticBlock;
217 }
218
219 std::error_code EC;
220 if ((EC = visitStartOfDiagnostic()))
221 return EC;
222
223 SmallVector<uint64_t, 16> Record;
224 while (true) {
225 unsigned BlockOrCode = 0;
226 llvm::ErrorOr<Cursor> Res = skipUntilRecordOrBlock(Stream, BlockOrCode);
227 if (!Res)
228 Res.getError();
229
230 switch (Res.get()) {
231 case Cursor::BlockBegin:
232 // The only blocks we care about are subdiagnostics.
233 if (BlockOrCode == serialized_diags::BLOCK_DIAG) {
234 if ((EC = readDiagnosticBlock(Stream)))
235 return EC;
236 } else if (llvm::Error Err = Stream.SkipBlock()) {
237 // FIXME this drops the error on the floor.
238 consumeError(std::move(Err));
239 return SDError::MalformedSubBlock;
240 }
241 continue;
242 case Cursor::BlockEnd:
243 if ((EC = visitEndOfDiagnostic()))
244 return EC;
245 return {};
246 case Cursor::Record:
247 break;
248 }
249
250 // Read the record.
251 Record.clear();
252 StringRef Blob;
253 Expected<unsigned> MaybeRecID =
254 Stream.readRecord(BlockOrCode, Record, &Blob);
255 if (!MaybeRecID)
256 return errorToErrorCode(MaybeRecID.takeError());
257 unsigned RecID = MaybeRecID.get();
258
259 if (RecID < serialized_diags::RECORD_FIRST ||
260 RecID > serialized_diags::RECORD_LAST)
261 continue;
262
263 switch ((RecordIDs)RecID) {
264 case RECORD_CATEGORY:
265 // A category has ID and name size.
266 if (Record.size() != 2)
267 return SDError::MalformedDiagnosticRecord;
268 if ((EC = visitCategoryRecord(Record[0], Blob)))
269 return EC;
270 continue;
271 case RECORD_DIAG:
272 // A diagnostic has severity, location (4), category, flag, and message
273 // size.
274 if (Record.size() != 8)
275 return SDError::MalformedDiagnosticRecord;
276 if ((EC = visitDiagnosticRecord(
277 Record[0], Location(Record[1], Record[2], Record[3], Record[4]),
278 Record[5], Record[6], Blob)))
279 return EC;
280 continue;
281 case RECORD_DIAG_FLAG:
282 // A diagnostic flag has ID and name size.
283 if (Record.size() != 2)
284 return SDError::MalformedDiagnosticRecord;
285 if ((EC = visitDiagFlagRecord(Record[0], Blob)))
286 return EC;
287 continue;
288 case RECORD_FILENAME:
289 // A filename has ID, size, timestamp, and name size. The size and
290 // timestamp are legacy fields that are always zero these days.
291 if (Record.size() != 4)
292 return SDError::MalformedDiagnosticRecord;
293 if ((EC = visitFilenameRecord(Record[0], Record[1], Record[2], Blob)))
294 return EC;
295 continue;
296 case RECORD_FIXIT:
297 // A fixit has two locations (4 each) and message size.
298 if (Record.size() != 9)
299 return SDError::MalformedDiagnosticRecord;
300 if ((EC = visitFixitRecord(
301 Location(Record[0], Record[1], Record[2], Record[3]),
302 Location(Record[4], Record[5], Record[6], Record[7]), Blob)))
303 return EC;
304 continue;
305 case RECORD_SOURCE_RANGE:
306 // A source range is two locations (4 each).
307 if (Record.size() != 8)
308 return SDError::MalformedDiagnosticRecord;
309 if ((EC = visitSourceRangeRecord(
310 Location(Record[0], Record[1], Record[2], Record[3]),
311 Location(Record[4], Record[5], Record[6], Record[7]))))
312 return EC;
313 continue;
314 case RECORD_VERSION:
315 // A version is just a number.
316 if (Record.size() != 1)
317 return SDError::MalformedDiagnosticRecord;
318 if ((EC = visitVersionRecord(Record[0])))
319 return EC;
320 continue;
321 }
322 }
323}
324
325namespace {
326
327class SDErrorCategoryType final : public std::error_category {
328 const char *name() const noexcept override {
329 return "clang.serialized_diags";
330 }
331
332 std::string message(int IE) const override {
333 auto E = static_cast<SDError>(IE);
334 switch (E) {
335 case SDError::CouldNotLoad:
336 return "Failed to open diagnostics file";
337 case SDError::InvalidSignature:
338 return "Invalid diagnostics signature";
339 case SDError::InvalidDiagnostics:
340 return "Parse error reading diagnostics";
341 case SDError::MalformedTopLevelBlock:
342 return "Malformed block at top-level of diagnostics";
343 case SDError::MalformedSubBlock:
344 return "Malformed sub-block in a diagnostic";
345 case SDError::MalformedBlockInfoBlock:
346 return "Malformed BlockInfo block";
347 case SDError::MalformedMetadataBlock:
348 return "Malformed Metadata block";
349 case SDError::MalformedDiagnosticBlock:
350 return "Malformed Diagnostic block";
351 case SDError::MalformedDiagnosticRecord:
352 return "Malformed Diagnostic record";
353 case SDError::MissingVersion:
354 return "No version provided in diagnostics";
355 case SDError::VersionMismatch:
356 return "Unsupported diagnostics version";
357 case SDError::UnsupportedConstruct:
358 return "Bitcode constructs that are not supported in diagnostics appear";
359 case SDError::HandlerFailed:
360 return "Generic error occurred while handling a record";
361 }
362 llvm_unreachable("Unknown error type!")__builtin_unreachable();
363 }
364};
365
366} // namespace
367
368static llvm::ManagedStatic<SDErrorCategoryType> ErrorCategory;
369const std::error_category &clang::serialized_diags::SDErrorCategory() {
370 return *ErrorCategory;
371}
←

/usr/src/gnu/usr.bin/clang/libclangFrontend/../../../llvm/llvm/include/llvm/Bitstream/BitstreamReader.h

→
1//===- BitstreamReader.h - Low-level bitstream reader interface -*- 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 header defines the BitstreamReader class. This class can be used to
10// read an arbitrary bitstream, regardless of its contents.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_BITSTREAM_BITSTREAMREADER_H
15#define LLVM_BITSTREAM_BITSTREAMREADER_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/Bitstream/BitCodes.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/Error.h"
22#include "llvm/Support/ErrorHandling.h"
23#include "llvm/Support/MathExtras.h"
24#include "llvm/Support/MemoryBuffer.h"
25#include <algorithm>
26#include <cassert>
27#include <climits>
28#include <cstddef>
29#include <cstdint>
30#include <memory>
31#include <string>
32#include <utility>
33#include <vector>
34
35namespace llvm {
36
37/// This class maintains the abbreviations read from a block info block.
38class BitstreamBlockInfo {
39public:
40 /// This contains information emitted to BLOCKINFO_BLOCK blocks. These
41 /// describe abbreviations that all blocks of the specified ID inherit.
42 struct BlockInfo {
43 unsigned BlockID = 0;
44 std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs;
45 std::string Name;
46 std::vector<std::pair<unsigned, std::string>> RecordNames;
47 };
48
49private:
50 std::vector<BlockInfo> BlockInfoRecords;
51
52public:
53 /// If there is block info for the specified ID, return it, otherwise return
54 /// null.
55 const BlockInfo *getBlockInfo(unsigned BlockID) const {
56 // Common case, the most recent entry matches BlockID.
57 if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
58 return &BlockInfoRecords.back();
59
60 for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
61 i != e; ++i)
62 if (BlockInfoRecords[i].BlockID == BlockID)
63 return &BlockInfoRecords[i];
64 return nullptr;
65 }
66
67 BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
68 if (const BlockInfo *BI = getBlockInfo(BlockID))
69 return *const_cast<BlockInfo*>(BI);
70
71 // Otherwise, add a new record.
72 BlockInfoRecords.emplace_back();
73 BlockInfoRecords.back().BlockID = BlockID;
74 return BlockInfoRecords.back();
75 }
76};
77
78/// This represents a position within a bitstream. There may be multiple
79/// independent cursors reading within one bitstream, each maintaining their
80/// own local state.
81class SimpleBitstreamCursor {
82 ArrayRef<uint8_t> BitcodeBytes;
83 size_t NextChar = 0;
84
85public:
86 /// This is the current data we have pulled from the stream but have not
87 /// returned to the client. This is specifically and intentionally defined to
88 /// follow the word size of the host machine for efficiency. We use word_t in
89 /// places that are aware of this to make it perfectly explicit what is going
90 /// on.
91 using word_t = size_t;
92
93private:
94 word_t CurWord = 0;
95
96 /// This is the number of bits in CurWord that are valid. This is always from
97 /// [0...bits_of(size_t)-1] inclusive.
98 unsigned BitsInCurWord = 0;
99
100public:
101 static const constexpr size_t MaxChunkSize = sizeof(word_t) * 8;
102
103 SimpleBitstreamCursor() = default;
104 explicit SimpleBitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
105 : BitcodeBytes(BitcodeBytes) {}
106 explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
107 : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
108 explicit SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
109 : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}
110
111 bool canSkipToPos(size_t pos) const {
112 // pos can be skipped to if it is a valid address or one byte past the end.
113 return pos <= BitcodeBytes.size();
114 }
115
116 bool AtEndOfStream() {
117 return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
118 }
119
120 /// Return the bit # of the bit we are reading.
121 uint64_t GetCurrentBitNo() const {
122 return NextChar*CHAR_BIT8 - BitsInCurWord;
123 }
124
125 // Return the byte # of the current bit.
126 uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }
127
128 ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }
129
130 /// Reset the stream to the specified bit number.
131 Error JumpToBit(uint64_t BitNo) {
132 size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
133 unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
134 assert(canSkipToPos(ByteNo) && "Invalid location")((void)0);
135
136 // Move the cursor to the right word.
137 NextChar = ByteNo;
138 BitsInCurWord = 0;
139
140 // Skip over any bits that are already consumed.
141 if (WordBitNo) {
142 if (Expected<word_t> Res = Read(WordBitNo))
143 return Error::success();
144 else
145 return Res.takeError();
146 }
147
148 return Error::success();
149 }
150
151 /// Get a pointer into the bitstream at the specified byte offset.
152 const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
153 return BitcodeBytes.data() + ByteNo;
154 }
155
156 /// Get a pointer into the bitstream at the specified bit offset.
157 ///
158 /// The bit offset must be on a byte boundary.
159 const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
160 assert(!(BitNo % 8) && "Expected bit on byte boundary")((void)0);
161 return getPointerToByte(BitNo / 8, NumBytes);
162 }
163
164 Error fillCurWord() {
165 if (NextChar >= BitcodeBytes.size())
166 return createStringError(std::errc::io_error,
167 "Unexpected end of file reading %u of %u bytes",
168 NextChar, BitcodeBytes.size());
169
170 // Read the next word from the stream.
171 const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
172 unsigned BytesRead;
173 if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
174 BytesRead = sizeof(word_t);
175 CurWord =
176 support::endian::read<word_t, support::little, support::unaligned>(
177 NextCharPtr);
178 } else {
179 // Short read.
180 BytesRead = BitcodeBytes.size() - NextChar;
181 CurWord = 0;
182 for (unsigned B = 0; B != BytesRead; ++B)
183 CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
184 }
185 NextChar += BytesRead;
186 BitsInCurWord = BytesRead * 8;
187 return Error::success();
188 }
189
190 Expected<word_t> Read(unsigned NumBits) {
191 static const unsigned BitsInWord = MaxChunkSize;
192
193 assert(NumBits && NumBits <= BitsInWord &&((void)0)
194 "Cannot return zero or more than BitsInWord bits!")((void)0);
195
196 static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
5
←
'?' condition is true
→
197
198 // If the field is fully contained by CurWord, return it quickly.
199 if (BitsInCurWord >= NumBits) {
6
←
Assuming 'NumBits' is > field 'BitsInCurWord'
→
7
←
Taking false branch
→
200 word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
201
202 // Use a mask to avoid undefined behavior.
203 CurWord >>= (NumBits & Mask);
204
205 BitsInCurWord -= NumBits;
206 return R;
207 }
208
209 word_t R = BitsInCurWord
7.1
Field 'BitsInCurWord' is not equal to 0
7.1
Field 'BitsInCurWord' is not equal to 0
7.1
Field 'BitsInCurWord' is not equal to 0
 ? CurWord : 0;
8
←
'?' condition is true
→
210 unsigned BitsLeft = NumBits - BitsInCurWord;
211
212 if (Error fillResult = fillCurWord())
9
←
Calling 'Error::operator bool'
→
11
←
Returning from 'Error::operator bool'
→
12
←
Taking false branch
→
213 return std::move(fillResult);
214
215 // If we run out of data, abort.
216 if (BitsLeft > BitsInCurWord)
13
←
Assuming 'BitsLeft' is <= field 'BitsInCurWord'
→
14
←
Taking false branch
→
217 return createStringError(std::errc::io_error,
218 "Unexpected end of file reading %u of %u bits",
219 BitsInCurWord, BitsLeft);
220
221 word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
15
←
The result of the right shift is undefined due to shifting by '64', which is greater or equal to the width of type 'llvm::SimpleBitstreamCursor::word_t'
222
223 // Use a mask to avoid undefined behavior.
224 CurWord >>= (BitsLeft & Mask);
225
226 BitsInCurWord -= BitsLeft;
227
228 R |= R2 << (NumBits - BitsLeft);
229
230 return R;
231 }
232
233 Expected<uint32_t> ReadVBR(unsigned NumBits) {
234 Expected<unsigned> MaybeRead = Read(NumBits);
235 if (!MaybeRead)
236 return MaybeRead;
237 uint32_t Piece = MaybeRead.get();
238
239 if ((Piece & (1U << (NumBits-1))) == 0)
240 return Piece;
241
242 uint32_t Result = 0;
243 unsigned NextBit = 0;
244 while (true) {
245 Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
246
247 if ((Piece & (1U << (NumBits-1))) == 0)
248 return Result;
249
250 NextBit += NumBits-1;
251 MaybeRead = Read(NumBits);
252 if (!MaybeRead)
253 return MaybeRead;
254 Piece = MaybeRead.get();
255 }
256 }
257
258 // Read a VBR that may have a value up to 64-bits in size. The chunk size of
259 // the VBR must still be <= 32 bits though.
260 Expected<uint64_t> ReadVBR64(unsigned NumBits) {
261 Expected<uint64_t> MaybeRead = Read(NumBits);
262 if (!MaybeRead)
263 return MaybeRead;
264 uint32_t Piece = MaybeRead.get();
265
266 if ((Piece & (1U << (NumBits-1))) == 0)
267 return uint64_t(Piece);
268
269 uint64_t Result = 0;
270 unsigned NextBit = 0;
271 while (true) {
272 Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
273
274 if ((Piece & (1U << (NumBits-1))) == 0)
275 return Result;
276
277 NextBit += NumBits-1;
278 MaybeRead = Read(NumBits);
279 if (!MaybeRead)
280 return MaybeRead;
281 Piece = MaybeRead.get();
282 }
283 }
284
285 void SkipToFourByteBoundary() {
286 // If word_t is 64-bits and if we've read less than 32 bits, just dump
287 // the bits we have up to the next 32-bit boundary.
288 if (sizeof(word_t) > 4 &&
289 BitsInCurWord >= 32) {
290 CurWord >>= BitsInCurWord-32;
291 BitsInCurWord = 32;
292 return;
293 }
294
295 BitsInCurWord = 0;
296 }
297
298 /// Return the size of the stream in bytes.
299 size_t SizeInBytes() const { return BitcodeBytes.size(); }
300
301 /// Skip to the end of the file.
302 void skipToEnd() { NextChar = BitcodeBytes.size(); }
303};
304
305/// When advancing through a bitstream cursor, each advance can discover a few
306/// different kinds of entries:
307struct BitstreamEntry {
308 enum {
309 Error, // Malformed bitcode was found.
310 EndBlock, // We've reached the end of the current block, (or the end of the
311 // file, which is treated like a series of EndBlock records.
312 SubBlock, // This is the start of a new subblock of a specific ID.
313 Record // This is a record with a specific AbbrevID.
314 } Kind;
315
316 unsigned ID;
317
318 static BitstreamEntry getError() {
319 BitstreamEntry E; E.Kind = Error; return E;
320 }
321
322 static BitstreamEntry getEndBlock() {
323 BitstreamEntry E; E.Kind = EndBlock; return E;
324 }
325
326 static BitstreamEntry getSubBlock(unsigned ID) {
327 BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
328 }
329
330 static BitstreamEntry getRecord(unsigned AbbrevID) {
331 BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
332 }
333};
334
335/// This represents a position within a bitcode file, implemented on top of a
336/// SimpleBitstreamCursor.
337///
338/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
339/// be passed by value.
340class BitstreamCursor : SimpleBitstreamCursor {
341 // This is the declared size of code values used for the current block, in
342 // bits.
343 unsigned CurCodeSize = 2;
344
345 /// Abbrevs installed at in this block.
346 std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
347
348 struct Block {
349 unsigned PrevCodeSize;
350 std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
351
352 explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
353 };
354
355 /// This tracks the codesize of parent blocks.
356 SmallVector<Block, 8> BlockScope;
357
358 BitstreamBlockInfo *BlockInfo = nullptr;
359
360public:
361 static const size_t MaxChunkSize = sizeof(word_t) * 8;
362
363 BitstreamCursor() = default;
364 explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
365 : SimpleBitstreamCursor(BitcodeBytes) {}
366 explicit BitstreamCursor(StringRef BitcodeBytes)
367 : SimpleBitstreamCursor(BitcodeBytes) {}
368 explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
369 : SimpleBitstreamCursor(BitcodeBytes) {}
370
371 using SimpleBitstreamCursor::AtEndOfStream;
372 using SimpleBitstreamCursor::canSkipToPos;
373 using SimpleBitstreamCursor::fillCurWord;
374 using SimpleBitstreamCursor::getBitcodeBytes;
375 using SimpleBitstreamCursor::GetCurrentBitNo;
376 using SimpleBitstreamCursor::getCurrentByteNo;
377 using SimpleBitstreamCursor::getPointerToByte;
378 using SimpleBitstreamCursor::JumpToBit;
379 using SimpleBitstreamCursor::Read;
380 using SimpleBitstreamCursor::ReadVBR;
381 using SimpleBitstreamCursor::ReadVBR64;
382 using SimpleBitstreamCursor::SizeInBytes;
383 using SimpleBitstreamCursor::skipToEnd;
384
385 /// Return the number of bits used to encode an abbrev #.
386 unsigned getAbbrevIDWidth() const { return CurCodeSize; }
387
388 /// Flags that modify the behavior of advance().
389 enum {
390 /// If this flag is used, the advance() method does not automatically pop
391 /// the block scope when the end of a block is reached.
392 AF_DontPopBlockAtEnd = 1,
393
394 /// If this flag is used, abbrev entries are returned just like normal
395 /// records.
396 AF_DontAutoprocessAbbrevs = 2
397 };
398
399 /// Advance the current bitstream, returning the next entry in the stream.
400 Expected<BitstreamEntry> advance(unsigned Flags = 0) {
401 while (true) {
402 if (AtEndOfStream())
403 return BitstreamEntry::getError();
404
405 Expected<unsigned> MaybeCode = ReadCode();
406 if (!MaybeCode)
407 return MaybeCode.takeError();
408 unsigned Code = MaybeCode.get();
409
410 if (Code == bitc::END_BLOCK) {
411 // Pop the end of the block unless Flags tells us not to.
412 if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
413 return BitstreamEntry::getError();
414 return BitstreamEntry::getEndBlock();
415 }
416
417 if (Code == bitc::ENTER_SUBBLOCK) {
418 if (Expected<unsigned> MaybeSubBlock = ReadSubBlockID())
419 return BitstreamEntry::getSubBlock(MaybeSubBlock.get());
420 else
421 return MaybeSubBlock.takeError();
422 }
423
424 if (Code == bitc::DEFINE_ABBREV &&
425 !(Flags & AF_DontAutoprocessAbbrevs)) {
426 // We read and accumulate abbrev's, the client can't do anything with
427 // them anyway.
428 if (Error Err = ReadAbbrevRecord())
429 return std::move(Err);
430 continue;
431 }
432
433 return BitstreamEntry::getRecord(Code);
434 }
435 }
436
437 /// This is a convenience function for clients that don't expect any
438 /// subblocks. This just skips over them automatically.
439 Expected<BitstreamEntry> advanceSkippingSubblocks(unsigned Flags = 0) {
440 while (true) {
441 // If we found a normal entry, return it.
442 Expected<BitstreamEntry> MaybeEntry = advance(Flags);
443 if (!MaybeEntry)
444 return MaybeEntry;
445 BitstreamEntry Entry = MaybeEntry.get();
446
447 if (Entry.Kind != BitstreamEntry::SubBlock)
448 return Entry;
449
450 // If we found a sub-block, just skip over it and check the next entry.
451 if (Error Err = SkipBlock())
452 return std::move(Err);
453 }
454 }
455
456 Expected<unsigned> ReadCode() { return Read(CurCodeSize); }
457
458 // Block header:
459 // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
460
461 /// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
462 Expected<unsigned> ReadSubBlockID() { return ReadVBR(bitc::BlockIDWidth); }
463
464 /// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
465 /// of this block.
466 Error SkipBlock() {
467 // Read and ignore the codelen value.
468 if (Expected<uint32_t> Res = ReadVBR(bitc::CodeLenWidth))
469 ; // Since we are skipping this block, we don't care what code widths are
470 // used inside of it.
471 else
472 return Res.takeError();
473
474 SkipToFourByteBoundary();
475 Expected<unsigned> MaybeNum = Read(bitc::BlockSizeWidth);
476 if (!MaybeNum)
477 return MaybeNum.takeError();
478 size_t NumFourBytes = MaybeNum.get();
479
480 // Check that the block wasn't partially defined, and that the offset isn't
481 // bogus.
482 size_t SkipTo = GetCurrentBitNo() + NumFourBytes * 4 * 8;
483 if (AtEndOfStream())
484 return createStringError(std::errc::illegal_byte_sequence,
485 "can't skip block: already at end of stream");
486 if (!canSkipToPos(SkipTo / 8))
487 return createStringError(std::errc::illegal_byte_sequence,
488 "can't skip to bit %zu from %" PRIu64"llu", SkipTo,
489 GetCurrentBitNo());
490
491 if (Error Res = JumpToBit(SkipTo))
492 return Res;
493
494 return Error::success();
495 }
496
497 /// Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
498 Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
499
500 bool ReadBlockEnd() {
501 if (BlockScope.empty()) return true;
502
503 // Block tail:
504 // [END_BLOCK, <align4bytes>]
505 SkipToFourByteBoundary();
506
507 popBlockScope();
508 return false;
509 }
510
511private:
512 void popBlockScope() {
513 CurCodeSize = BlockScope.back().PrevCodeSize;
514
515 CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
516 BlockScope.pop_back();
517 }
518
519 //===--------------------------------------------------------------------===//
520 // Record Processing
521 //===--------------------------------------------------------------------===//
522
523public:
524 /// Return the abbreviation for the specified AbbrevId.
525 const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
526 unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
527 if (AbbrevNo >= CurAbbrevs.size())
528 report_fatal_error("Invalid abbrev number");
529 return CurAbbrevs[AbbrevNo].get();
530 }
531
532 /// Read the current record and discard it, returning the code for the record.
533 Expected<unsigned> skipRecord(unsigned AbbrevID);
534
535 Expected<unsigned> readRecord(unsigned AbbrevID,
536 SmallVectorImpl<uint64_t> &Vals,
537 StringRef *Blob = nullptr);
538
539 //===--------------------------------------------------------------------===//
540 // Abbrev Processing
541 //===--------------------------------------------------------------------===//
542 Error ReadAbbrevRecord();
543
544 /// Read and return a block info block from the bitstream. If an error was
545 /// encountered, return None.
546 ///
547 /// \param ReadBlockInfoNames Whether to read block/record name information in
548 /// the BlockInfo block. Only llvm-bcanalyzer uses this.
549 Expected<Optional<BitstreamBlockInfo>>
550 ReadBlockInfoBlock(bool ReadBlockInfoNames = false);
551
552 /// Set the block info to be used by this BitstreamCursor to interpret
553 /// abbreviated records.
554 void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
555};
556
557} // end llvm namespace
558
559#endif // LLVM_BITSTREAM_BITSTREAMREADER_H
←

/usr/src/gnu/usr.bin/clang/libclangFrontend/../../../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;
10
←
Returning zero, which participates in a condition later
→
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)
1052 return std::move(*E);
1053 consumeError(E.takeError());
1054 return None;
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