LLVM 17.0.0git
BitstreamReader.h
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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"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/Error.h"
23#include <algorithm>
24#include <cassert>
25#include <climits>
26#include <cstddef>
27#include <cstdint>
28#include <memory>
29#include <optional>
30#include <string>
31#include <utility>
32#include <vector>
33
34namespace llvm {
35
36/// This class maintains the abbreviations read from a block info block.
38public:
39 /// This contains information emitted to BLOCKINFO_BLOCK blocks. These
40 /// describe abbreviations that all blocks of the specified ID inherit.
41 struct BlockInfo {
42 unsigned BlockID = 0;
43 std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs;
44 std::string Name;
45 std::vector<std::pair<unsigned, std::string>> RecordNames;
46 };
47
48private:
49 std::vector<BlockInfo> BlockInfoRecords;
50
51public:
52 /// If there is block info for the specified ID, return it, otherwise return
53 /// null.
54 const BlockInfo *getBlockInfo(unsigned BlockID) const {
55 // Common case, the most recent entry matches BlockID.
56 if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
57 return &BlockInfoRecords.back();
58
59 for (const BlockInfo &BI : BlockInfoRecords)
60 if (BI.BlockID == BlockID)
61 return &BI;
62 return nullptr;
63 }
64
65 BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
66 if (const BlockInfo *BI = getBlockInfo(BlockID))
67 return *const_cast<BlockInfo*>(BI);
68
69 // Otherwise, add a new record.
70 BlockInfoRecords.emplace_back();
71 BlockInfoRecords.back().BlockID = BlockID;
72 return BlockInfoRecords.back();
73 }
74};
75
76/// This represents a position within a bitstream. There may be multiple
77/// independent cursors reading within one bitstream, each maintaining their
78/// own local state.
80 ArrayRef<uint8_t> BitcodeBytes;
81 size_t NextChar = 0;
82
83public:
84 /// This is the current data we have pulled from the stream but have not
85 /// returned to the client. This is specifically and intentionally defined to
86 /// follow the word size of the host machine for efficiency. We use word_t in
87 /// places that are aware of this to make it perfectly explicit what is going
88 /// on.
89 using word_t = size_t;
90
91private:
92 word_t CurWord = 0;
93
94 /// This is the number of bits in CurWord that are valid. This is always from
95 /// [0...bits_of(size_t)-1] inclusive.
96 unsigned BitsInCurWord = 0;
97
98public:
101 : BitcodeBytes(BitcodeBytes) {}
102 explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
103 : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
105 : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}
106
107 bool canSkipToPos(size_t pos) const {
108 // pos can be skipped to if it is a valid address or one byte past the end.
109 return pos <= BitcodeBytes.size();
110 }
111
113 return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
114 }
115
116 /// Return the bit # of the bit we are reading.
118 return NextChar*CHAR_BIT - BitsInCurWord;
119 }
120
121 // Return the byte # of the current bit.
122 uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }
123
124 ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }
125
126 /// Reset the stream to the specified bit number.
128 size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
129 unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
130 assert(canSkipToPos(ByteNo) && "Invalid location");
131
132 // Move the cursor to the right word.
133 NextChar = ByteNo;
134 BitsInCurWord = 0;
135
136 // Skip over any bits that are already consumed.
137 if (WordBitNo) {
138 if (Expected<word_t> Res = Read(WordBitNo))
139 return Error::success();
140 else
141 return Res.takeError();
142 }
143
144 return Error::success();
145 }
146
147 /// Get a pointer into the bitstream at the specified byte offset.
148 const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
149 return BitcodeBytes.data() + ByteNo;
150 }
151
152 /// Get a pointer into the bitstream at the specified bit offset.
153 ///
154 /// The bit offset must be on a byte boundary.
155 const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
156 assert(!(BitNo % 8) && "Expected bit on byte boundary");
157 return getPointerToByte(BitNo / 8, NumBytes);
158 }
159
161 if (NextChar >= BitcodeBytes.size())
162 return createStringError(std::errc::io_error,
163 "Unexpected end of file reading %u of %u bytes",
164 NextChar, BitcodeBytes.size());
165
166 // Read the next word from the stream.
167 const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
168 unsigned BytesRead;
169 if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
170 BytesRead = sizeof(word_t);
171 CurWord =
172 support::endian::read<word_t, support::little, support::unaligned>(
173 NextCharPtr);
174 } else {
175 // Short read.
176 BytesRead = BitcodeBytes.size() - NextChar;
177 CurWord = 0;
178 for (unsigned B = 0; B != BytesRead; ++B)
179 CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
180 }
181 NextChar += BytesRead;
182 BitsInCurWord = BytesRead * 8;
183 return Error::success();
184 }
185
186 Expected<word_t> Read(unsigned NumBits) {
187 static const unsigned BitsInWord = sizeof(word_t) * 8;
188
189 assert(NumBits && NumBits <= BitsInWord &&
190 "Cannot return zero or more than BitsInWord bits!");
191
192 static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
193
194 // If the field is fully contained by CurWord, return it quickly.
195 if (BitsInCurWord >= NumBits) {
196 word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
197
198 // Use a mask to avoid undefined behavior.
199 CurWord >>= (NumBits & Mask);
200
201 BitsInCurWord -= NumBits;
202 return R;
203 }
204
205 word_t R = BitsInCurWord ? CurWord : 0;
206 unsigned BitsLeft = NumBits - BitsInCurWord;
207
208 if (Error fillResult = fillCurWord())
209 return std::move(fillResult);
210
211 // If we run out of data, abort.
212 if (BitsLeft > BitsInCurWord)
213 return createStringError(std::errc::io_error,
214 "Unexpected end of file reading %u of %u bits",
215 BitsInCurWord, BitsLeft);
216
217 word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
218
219 // Use a mask to avoid undefined behavior.
220 CurWord >>= (BitsLeft & Mask);
221
222 BitsInCurWord -= BitsLeft;
223
224 R |= R2 << (NumBits - BitsLeft);
225
226 return R;
227 }
228
229 Expected<uint32_t> ReadVBR(const unsigned NumBits) {
230 Expected<unsigned> MaybeRead = Read(NumBits);
231 if (!MaybeRead)
232 return MaybeRead;
233 uint32_t Piece = MaybeRead.get();
234
235 assert(NumBits <= 32 && NumBits >= 1 && "Invalid NumBits value");
236 const uint32_t MaskBitOrder = (NumBits - 1);
237 const uint32_t Mask = 1UL << MaskBitOrder;
238
239 if ((Piece & Mask) == 0)
240 return Piece;
241
242 uint32_t Result = 0;
243 unsigned NextBit = 0;
244 while (true) {
245 Result |= (Piece & (Mask - 1)) << NextBit;
246
247 if ((Piece & Mask) == 0)
248 return Result;
249
250 NextBit += NumBits-1;
251 if (NextBit >= 32)
252 return createStringError(std::errc::illegal_byte_sequence,
253 "Unterminated VBR");
254
255 MaybeRead = Read(NumBits);
256 if (!MaybeRead)
257 return MaybeRead;
258 Piece = MaybeRead.get();
259 }
260 }
261
262 // Read a VBR that may have a value up to 64-bits in size. The chunk size of
263 // the VBR must still be <= 32 bits though.
264 Expected<uint64_t> ReadVBR64(const unsigned NumBits) {
265 Expected<uint64_t> MaybeRead = Read(NumBits);
266 if (!MaybeRead)
267 return MaybeRead;
268 uint32_t Piece = MaybeRead.get();
269 assert(NumBits <= 32 && NumBits >= 1 && "Invalid NumBits value");
270 const uint32_t MaskBitOrder = (NumBits - 1);
271 const uint32_t Mask = 1UL << MaskBitOrder;
272
273 if ((Piece & Mask) == 0)
274 return uint64_t(Piece);
275
276 uint64_t Result = 0;
277 unsigned NextBit = 0;
278 while (true) {
279 Result |= uint64_t(Piece & (Mask - 1)) << NextBit;
280
281 if ((Piece & Mask) == 0)
282 return Result;
283
284 NextBit += NumBits-1;
285 if (NextBit >= 64)
286 return createStringError(std::errc::illegal_byte_sequence,
287 "Unterminated VBR");
288
289 MaybeRead = Read(NumBits);
290 if (!MaybeRead)
291 return MaybeRead;
292 Piece = MaybeRead.get();
293 }
294 }
295
297 // If word_t is 64-bits and if we've read less than 32 bits, just dump
298 // the bits we have up to the next 32-bit boundary.
299 if (sizeof(word_t) > 4 &&
300 BitsInCurWord >= 32) {
301 CurWord >>= BitsInCurWord-32;
302 BitsInCurWord = 32;
303 return;
304 }
305
306 BitsInCurWord = 0;
307 }
308
309 /// Return the size of the stream in bytes.
310 size_t SizeInBytes() const { return BitcodeBytes.size(); }
311
312 /// Skip to the end of the file.
313 void skipToEnd() { NextChar = BitcodeBytes.size(); }
314
315 /// Check whether a reservation of Size elements is plausible.
316 bool isSizePlausible(size_t Size) const {
317 // Don't allow reserving more elements than the number of bits, assuming
318 // at least one bit is needed to encode an element.
319 return Size < BitcodeBytes.size() * 8;
320 }
321};
322
323/// When advancing through a bitstream cursor, each advance can discover a few
324/// different kinds of entries:
326 enum {
327 Error, // Malformed bitcode was found.
328 EndBlock, // We've reached the end of the current block, (or the end of the
329 // file, which is treated like a series of EndBlock records.
330 SubBlock, // This is the start of a new subblock of a specific ID.
331 Record // This is a record with a specific AbbrevID.
333
334 unsigned ID;
335
337 BitstreamEntry E; E.Kind = Error; return E;
338 }
339
341 BitstreamEntry E; E.Kind = EndBlock; return E;
342 }
343
344 static BitstreamEntry getSubBlock(unsigned ID) {
345 BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
346 }
347
348 static BitstreamEntry getRecord(unsigned AbbrevID) {
349 BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
350 }
351};
352
353/// This represents a position within a bitcode file, implemented on top of a
354/// SimpleBitstreamCursor.
355///
356/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
357/// be passed by value.
359 // This is the declared size of code values used for the current block, in
360 // bits.
361 unsigned CurCodeSize = 2;
362
363 /// Abbrevs installed at in this block.
364 std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
365
366 struct Block {
367 unsigned PrevCodeSize;
368 std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
369
370 explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
371 };
372
373 /// This tracks the codesize of parent blocks.
374 SmallVector<Block, 8> BlockScope;
375
376 BitstreamBlockInfo *BlockInfo = nullptr;
377
378public:
379 static const size_t MaxChunkSize = 32;
380
381 BitstreamCursor() = default;
382 explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
383 : SimpleBitstreamCursor(BitcodeBytes) {}
384 explicit BitstreamCursor(StringRef BitcodeBytes)
385 : SimpleBitstreamCursor(BitcodeBytes) {}
386 explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
387 : SimpleBitstreamCursor(BitcodeBytes) {}
388
402
403 /// Return the number of bits used to encode an abbrev #.
404 unsigned getAbbrevIDWidth() const { return CurCodeSize; }
405
406 /// Flags that modify the behavior of advance().
407 enum {
408 /// If this flag is used, the advance() method does not automatically pop
409 /// the block scope when the end of a block is reached.
411
412 /// If this flag is used, abbrev entries are returned just like normal
413 /// records.
415 };
416
417 /// Advance the current bitstream, returning the next entry in the stream.
418 Expected<BitstreamEntry> advance(unsigned Flags = 0) {
419 while (true) {
420 if (AtEndOfStream())
422
423 Expected<unsigned> MaybeCode = ReadCode();
424 if (!MaybeCode)
425 return MaybeCode.takeError();
426 unsigned Code = MaybeCode.get();
427
428 if (Code == bitc::END_BLOCK) {
429 // Pop the end of the block unless Flags tells us not to.
430 if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
433 }
434
435 if (Code == bitc::ENTER_SUBBLOCK) {
436 if (Expected<unsigned> MaybeSubBlock = ReadSubBlockID())
437 return BitstreamEntry::getSubBlock(MaybeSubBlock.get());
438 else
439 return MaybeSubBlock.takeError();
440 }
441
442 if (Code == bitc::DEFINE_ABBREV &&
443 !(Flags & AF_DontAutoprocessAbbrevs)) {
444 // We read and accumulate abbrev's, the client can't do anything with
445 // them anyway.
446 if (Error Err = ReadAbbrevRecord())
447 return std::move(Err);
448 continue;
449 }
450
451 return BitstreamEntry::getRecord(Code);
452 }
453 }
454
455 /// This is a convenience function for clients that don't expect any
456 /// subblocks. This just skips over them automatically.
458 while (true) {
459 // If we found a normal entry, return it.
460 Expected<BitstreamEntry> MaybeEntry = advance(Flags);
461 if (!MaybeEntry)
462 return MaybeEntry;
463 BitstreamEntry Entry = MaybeEntry.get();
464
465 if (Entry.Kind != BitstreamEntry::SubBlock)
466 return Entry;
467
468 // If we found a sub-block, just skip over it and check the next entry.
469 if (Error Err = SkipBlock())
470 return std::move(Err);
471 }
472 }
473
474 Expected<unsigned> ReadCode() { return Read(CurCodeSize); }
475
476 // Block header:
477 // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
478
479 /// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
481
482 /// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
483 /// of this block.
485 // Read and ignore the codelen value.
487 ; // Since we are skipping this block, we don't care what code widths are
488 // used inside of it.
489 else
490 return Res.takeError();
491
494 if (!MaybeNum)
495 return MaybeNum.takeError();
496 size_t NumFourBytes = MaybeNum.get();
497
498 // Check that the block wasn't partially defined, and that the offset isn't
499 // bogus.
500 size_t SkipTo = GetCurrentBitNo() + NumFourBytes * 4 * 8;
501 if (AtEndOfStream())
502 return createStringError(std::errc::illegal_byte_sequence,
503 "can't skip block: already at end of stream");
504 if (!canSkipToPos(SkipTo / 8))
505 return createStringError(std::errc::illegal_byte_sequence,
506 "can't skip to bit %zu from %" PRIu64, SkipTo,
508
509 if (Error Res = JumpToBit(SkipTo))
510 return Res;
511
512 return Error::success();
513 }
514
515 /// Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
516 Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
517
519 if (BlockScope.empty()) return true;
520
521 // Block tail:
522 // [END_BLOCK, <align4bytes>]
524
525 popBlockScope();
526 return false;
527 }
528
529private:
530 void popBlockScope() {
531 CurCodeSize = BlockScope.back().PrevCodeSize;
532
533 CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
534 BlockScope.pop_back();
535 }
536
537 //===--------------------------------------------------------------------===//
538 // Record Processing
539 //===--------------------------------------------------------------------===//
540
541public:
542 /// Return the abbreviation for the specified AbbrevId.
544 unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
545 if (AbbrevNo >= CurAbbrevs.size())
546 return createStringError(
547 std::errc::illegal_byte_sequence, "Invalid abbrev number");
548 return CurAbbrevs[AbbrevNo].get();
549 }
550
551 /// Read the current record and discard it, returning the code for the record.
552 Expected<unsigned> skipRecord(unsigned AbbrevID);
553
554 Expected<unsigned> readRecord(unsigned AbbrevID,
556 StringRef *Blob = nullptr);
557
558 //===--------------------------------------------------------------------===//
559 // Abbrev Processing
560 //===--------------------------------------------------------------------===//
562
563 /// Read and return a block info block from the bitstream. If an error was
564 /// encountered, return std::nullopt.
565 ///
566 /// \param ReadBlockInfoNames Whether to read block/record name information in
567 /// the BlockInfo block. Only llvm-bcanalyzer uses this.
569 ReadBlockInfoBlock(bool ReadBlockInfoNames = false);
570
571 /// Set the block info to be used by this BitstreamCursor to interpret
572 /// abbreviated records.
573 void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
574};
575
576} // end llvm namespace
577
578#endif // LLVM_BITSTREAM_BITSTREAMREADER_H
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
uint64_t Size
#define R2(n)
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This file defines the SmallVector class.
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:163
const T * data() const
Definition: ArrayRef.h:160
This class maintains the abbreviations read from a block info block.
const BlockInfo * getBlockInfo(unsigned BlockID) const
If there is block info for the specified ID, return it, otherwise return null.
BlockInfo & getOrCreateBlockInfo(unsigned BlockID)
This represents a position within a bitcode file, implemented on top of a SimpleBitstreamCursor.
Error JumpToBit(uint64_t BitNo)
Reset the stream to the specified bit number.
BitstreamCursor(StringRef BitcodeBytes)
uint64_t GetCurrentBitNo() const
Return the bit # of the bit we are reading.
Expected< unsigned > ReadSubBlockID()
Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
static const size_t MaxChunkSize
Expected< word_t > Read(unsigned NumBits)
Expected< BitstreamEntry > advance(unsigned Flags=0)
Advance the current bitstream, returning the next entry in the stream.
BitstreamCursor(MemoryBufferRef BitcodeBytes)
Expected< BitstreamEntry > advanceSkippingSubblocks(unsigned Flags=0)
This is a convenience function for clients that don't expect any subblocks.
Expected< const BitCodeAbbrev * > getAbbrev(unsigned AbbrevID)
Return the abbreviation for the specified AbbrevId.
void setBlockInfo(BitstreamBlockInfo *BI)
Set the block info to be used by this BitstreamCursor to interpret abbreviated records.
Expected< unsigned > readRecord(unsigned AbbrevID, SmallVectorImpl< uint64_t > &Vals, StringRef *Blob=nullptr)
Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP=nullptr)
Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
Error SkipBlock()
Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body of this block.
Expected< unsigned > skipRecord(unsigned AbbrevID)
Read the current record and discard it, returning the code for the record.
BitstreamCursor(ArrayRef< uint8_t > BitcodeBytes)
Expected< unsigned > ReadCode()
@ AF_DontAutoprocessAbbrevs
If this flag is used, abbrev entries are returned just like normal records.
@ AF_DontPopBlockAtEnd
If this flag is used, the advance() method does not automatically pop the block scope when the end of...
Expected< std::optional< BitstreamBlockInfo > > ReadBlockInfoBlock(bool ReadBlockInfoNames=false)
Read and return a block info block from the bitstream.
Expected< uint32_t > ReadVBR(const unsigned NumBits)
unsigned getAbbrevIDWidth() const
Return the number of bits used to encode an abbrev #.
bool canSkipToPos(size_t pos) const
Lightweight error class with error context and mandatory checking.
Definition: Error.h:156
static ErrorSuccess success()
Create a success value.
Definition: Error.h:330
Tagged union holding either a T or a Error.
Definition: Error.h:470
Error takeError()
Take ownership of the stored error.
Definition: Error.h:597
reference get()
Returns a reference to the stored T value.
Definition: Error.h:567
This represents a position within a bitstream.
Error JumpToBit(uint64_t BitNo)
Reset the stream to the specified bit number.
const uint8_t * getPointerToBit(uint64_t BitNo, uint64_t NumBytes)
Get a pointer into the bitstream at the specified bit offset.
uint64_t GetCurrentBitNo() const
Return the bit # of the bit we are reading.
Expected< uint64_t > ReadVBR64(const unsigned NumBits)
size_t SizeInBytes() const
Return the size of the stream in bytes.
ArrayRef< uint8_t > getBitcodeBytes() const
Expected< word_t > Read(unsigned NumBits)
const uint8_t * getPointerToByte(uint64_t ByteNo, uint64_t NumBytes)
Get a pointer into the bitstream at the specified byte offset.
SimpleBitstreamCursor(StringRef BitcodeBytes)
SimpleBitstreamCursor(ArrayRef< uint8_t > BitcodeBytes)
SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
size_t word_t
This is the current data we have pulled from the stream but have not returned to the client.
uint64_t getCurrentByteNo() const
bool isSizePlausible(size_t Size) const
Check whether a reservation of Size elements is plausible.
void skipToEnd()
Skip to the end of the file.
Expected< uint32_t > ReadVBR(const unsigned NumBits)
bool canSkipToPos(size_t pos) const
bool empty() const
Definition: SmallVector.h:94
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: SmallVector.h:577
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1200
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
@ DEFINE_ABBREV
DEFINE_ABBREV - Defines an abbrev for the current block.
Definition: BitCodeEnums.h:53
@ FIRST_APPLICATION_ABBREV
Definition: BitCodeEnums.h:60
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Error createStringError(std::error_code EC, char const *Fmt, const Ts &... Vals)
Create formatted StringError object.
Definition: Error.h:1246
This contains information emitted to BLOCKINFO_BLOCK blocks.
std::vector< std::pair< unsigned, std::string > > RecordNames
std::vector< std::shared_ptr< BitCodeAbbrev > > Abbrevs
When advancing through a bitstream cursor, each advance can discover a few different kinds of entries...
static BitstreamEntry getSubBlock(unsigned ID)
static BitstreamEntry getRecord(unsigned AbbrevID)
static BitstreamEntry getEndBlock()
static BitstreamEntry getError()
enum llvm::BitstreamEntry::@184 Kind