LLVM  15.0.0git
BitstreamWriter.h
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1 //===- BitstreamWriter.h - Low-level bitstream writer 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 BitstreamWriter class. This class can be used to
10 // write an arbitrary bitstream, regardless of its contents.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_BITSTREAM_BITSTREAMWRITER_H
15 #define LLVM_BITSTREAM_BITSTREAMWRITER_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/Optional.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringRef.h"
22 #include "llvm/Support/Endian.h"
25 #include <algorithm>
26 #include <vector>
27 
28 namespace llvm {
29 
31  /// Out - The buffer that keeps unflushed bytes.
33 
34  /// FS - The file stream that Out flushes to. If FS is nullptr, it does not
35  /// support read or seek, Out cannot be flushed until all data are written.
36  raw_fd_stream *FS;
37 
38  /// FlushThreshold - If FS is valid, this is the threshold (unit B) to flush
39  /// FS.
40  const uint64_t FlushThreshold;
41 
42  /// CurBit - Always between 0 and 31 inclusive, specifies the next bit to use.
43  unsigned CurBit;
44 
45  /// CurValue - The current value. Only bits < CurBit are valid.
46  uint32_t CurValue;
47 
48  /// CurCodeSize - This is the declared size of code values used for the
49  /// current block, in bits.
50  unsigned CurCodeSize;
51 
52  /// BlockInfoCurBID - When emitting a BLOCKINFO_BLOCK, this is the currently
53  /// selected BLOCK ID.
54  unsigned BlockInfoCurBID;
55 
56  /// CurAbbrevs - Abbrevs installed at in this block.
57  std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
58 
59  struct Block {
60  unsigned PrevCodeSize;
61  size_t StartSizeWord;
62  std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
63  Block(unsigned PCS, size_t SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {}
64  };
65 
66  /// BlockScope - This tracks the current blocks that we have entered.
67  std::vector<Block> BlockScope;
68 
69  /// BlockInfo - This contains information emitted to BLOCKINFO_BLOCK blocks.
70  /// These describe abbreviations that all blocks of the specified ID inherit.
71  struct BlockInfo {
72  unsigned BlockID;
73  std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs;
74  };
75  std::vector<BlockInfo> BlockInfoRecords;
76 
77  void WriteWord(unsigned Value) {
78  Value = support::endian::byte_swap<uint32_t, support::little>(Value);
79  Out.append(reinterpret_cast<const char *>(&Value),
80  reinterpret_cast<const char *>(&Value + 1));
81  }
82 
83  uint64_t GetNumOfFlushedBytes() const { return FS ? FS->tell() : 0; }
84 
85  size_t GetBufferOffset() const { return Out.size() + GetNumOfFlushedBytes(); }
86 
87  size_t GetWordIndex() const {
88  size_t Offset = GetBufferOffset();
89  assert((Offset & 3) == 0 && "Not 32-bit aligned");
90  return Offset / 4;
91  }
92 
93  /// If the related file stream supports reading, seeking and writing, flush
94  /// the buffer if its size is above a threshold.
95  void FlushToFile() {
96  if (!FS)
97  return;
98  if (Out.size() < FlushThreshold)
99  return;
100  FS->write((char *)&Out.front(), Out.size());
101  Out.clear();
102  }
103 
104 public:
105  /// Create a BitstreamWriter that writes to Buffer \p O.
106  ///
107  /// \p FS is the file stream that \p O flushes to incrementally. If \p FS is
108  /// null, \p O does not flush incrementially, but writes to disk at the end.
109  ///
110  /// \p FlushThreshold is the threshold (unit M) to flush \p O if \p FS is
111  /// valid. Flushing only occurs at (sub)block boundaries.
113  uint32_t FlushThreshold = 512)
114  : Out(O), FS(FS), FlushThreshold(FlushThreshold << 20), CurBit(0),
115  CurValue(0), CurCodeSize(2) {}
116 
118  assert(CurBit == 0 && "Unflushed data remaining");
119  assert(BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance");
120  }
121 
122  /// Retrieve the current position in the stream, in bits.
123  uint64_t GetCurrentBitNo() const { return GetBufferOffset() * 8 + CurBit; }
124 
125  /// Retrieve the number of bits currently used to encode an abbrev ID.
126  unsigned GetAbbrevIDWidth() const { return CurCodeSize; }
127 
128  //===--------------------------------------------------------------------===//
129  // Basic Primitives for emitting bits to the stream.
130  //===--------------------------------------------------------------------===//
131 
132  /// Backpatch a 32-bit word in the output at the given bit offset
133  /// with the specified value.
134  void BackpatchWord(uint64_t BitNo, unsigned NewWord) {
135  using namespace llvm::support;
136  uint64_t ByteNo = BitNo / 8;
137  uint64_t StartBit = BitNo & 7;
138  uint64_t NumOfFlushedBytes = GetNumOfFlushedBytes();
139 
140  if (ByteNo >= NumOfFlushedBytes) {
141  assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>(
142  &Out[ByteNo - NumOfFlushedBytes], StartBit)) &&
143  "Expected to be patching over 0-value placeholders");
144  endian::writeAtBitAlignment<uint32_t, little, unaligned>(
145  &Out[ByteNo - NumOfFlushedBytes], NewWord, StartBit);
146  return;
147  }
148 
149  // If the byte offset to backpatch is flushed, use seek to backfill data.
150  // First, save the file position to restore later.
151  uint64_t CurPos = FS->tell();
152 
153  // Copy data to update into Bytes from the file FS and the buffer Out.
154  char Bytes[9]; // Use one more byte to silence a warning from Visual C++.
155  size_t BytesNum = StartBit ? 8 : 4;
156  size_t BytesFromDisk = std::min(static_cast<uint64_t>(BytesNum), NumOfFlushedBytes - ByteNo);
157  size_t BytesFromBuffer = BytesNum - BytesFromDisk;
158 
159  // When unaligned, copy existing data into Bytes from the file FS and the
160  // buffer Out so that it can be updated before writing. For debug builds
161  // read bytes unconditionally in order to check that the existing value is 0
162  // as expected.
163 #ifdef NDEBUG
164  if (StartBit)
165 #endif
166  {
167  FS->seek(ByteNo);
168  ssize_t BytesRead = FS->read(Bytes, BytesFromDisk);
169  (void)BytesRead; // silence warning
170  assert(BytesRead >= 0 && static_cast<size_t>(BytesRead) == BytesFromDisk);
171  for (size_t i = 0; i < BytesFromBuffer; ++i)
172  Bytes[BytesFromDisk + i] = Out[i];
173  assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>(
174  Bytes, StartBit)) &&
175  "Expected to be patching over 0-value placeholders");
176  }
177 
178  // Update Bytes in terms of bit offset and value.
179  endian::writeAtBitAlignment<uint32_t, little, unaligned>(Bytes, NewWord,
180  StartBit);
181 
182  // Copy updated data back to the file FS and the buffer Out.
183  FS->seek(ByteNo);
184  FS->write(Bytes, BytesFromDisk);
185  for (size_t i = 0; i < BytesFromBuffer; ++i)
186  Out[i] = Bytes[BytesFromDisk + i];
187 
188  // Restore the file position.
189  FS->seek(CurPos);
190  }
191 
192  void BackpatchWord64(uint64_t BitNo, uint64_t Val) {
193  BackpatchWord(BitNo, (uint32_t)Val);
194  BackpatchWord(BitNo + 32, (uint32_t)(Val >> 32));
195  }
196 
197  void Emit(uint32_t Val, unsigned NumBits) {
198  assert(NumBits && NumBits <= 32 && "Invalid value size!");
199  assert((Val & ~(~0U >> (32-NumBits))) == 0 && "High bits set!");
200  CurValue |= Val << CurBit;
201  if (CurBit + NumBits < 32) {
202  CurBit += NumBits;
203  return;
204  }
205 
206  // Add the current word.
207  WriteWord(CurValue);
208 
209  if (CurBit)
210  CurValue = Val >> (32-CurBit);
211  else
212  CurValue = 0;
213  CurBit = (CurBit+NumBits) & 31;
214  }
215 
216  void FlushToWord() {
217  if (CurBit) {
218  WriteWord(CurValue);
219  CurBit = 0;
220  CurValue = 0;
221  }
222  }
223 
224  void EmitVBR(uint32_t Val, unsigned NumBits) {
225  assert(NumBits <= 32 && "Too many bits to emit!");
226  uint32_t Threshold = 1U << (NumBits-1);
227 
228  // Emit the bits with VBR encoding, NumBits-1 bits at a time.
229  while (Val >= Threshold) {
230  Emit((Val & ((1 << (NumBits-1))-1)) | (1 << (NumBits-1)), NumBits);
231  Val >>= NumBits-1;
232  }
233 
234  Emit(Val, NumBits);
235  }
236 
237  void EmitVBR64(uint64_t Val, unsigned NumBits) {
238  assert(NumBits <= 32 && "Too many bits to emit!");
239  if ((uint32_t)Val == Val)
240  return EmitVBR((uint32_t)Val, NumBits);
241 
242  uint32_t Threshold = 1U << (NumBits-1);
243 
244  // Emit the bits with VBR encoding, NumBits-1 bits at a time.
245  while (Val >= Threshold) {
246  Emit(((uint32_t)Val & ((1 << (NumBits - 1)) - 1)) | (1 << (NumBits - 1)),
247  NumBits);
248  Val >>= NumBits-1;
249  }
250 
251  Emit((uint32_t)Val, NumBits);
252  }
253 
254  /// EmitCode - Emit the specified code.
255  void EmitCode(unsigned Val) {
256  Emit(Val, CurCodeSize);
257  }
258 
259  //===--------------------------------------------------------------------===//
260  // Block Manipulation
261  //===--------------------------------------------------------------------===//
262 
263  /// getBlockInfo - If there is block info for the specified ID, return it,
264  /// otherwise return null.
265  BlockInfo *getBlockInfo(unsigned BlockID) {
266  // Common case, the most recent entry matches BlockID.
267  if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
268  return &BlockInfoRecords.back();
269 
270  for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
271  i != e; ++i)
272  if (BlockInfoRecords[i].BlockID == BlockID)
273  return &BlockInfoRecords[i];
274  return nullptr;
275  }
276 
277  void EnterSubblock(unsigned BlockID, unsigned CodeLen) {
278  // Block header:
279  // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
281  EmitVBR(BlockID, bitc::BlockIDWidth);
282  EmitVBR(CodeLen, bitc::CodeLenWidth);
283  FlushToWord();
284 
285  size_t BlockSizeWordIndex = GetWordIndex();
286  unsigned OldCodeSize = CurCodeSize;
287 
288  // Emit a placeholder, which will be replaced when the block is popped.
290 
291  CurCodeSize = CodeLen;
292 
293  // Push the outer block's abbrev set onto the stack, start out with an
294  // empty abbrev set.
295  BlockScope.emplace_back(OldCodeSize, BlockSizeWordIndex);
296  BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
297 
298  // If there is a blockinfo for this BlockID, add all the predefined abbrevs
299  // to the abbrev list.
300  if (BlockInfo *Info = getBlockInfo(BlockID))
301  append_range(CurAbbrevs, Info->Abbrevs);
302  }
303 
304  void ExitBlock() {
305  assert(!BlockScope.empty() && "Block scope imbalance!");
306  const Block &B = BlockScope.back();
307 
308  // Block tail:
309  // [END_BLOCK, <align4bytes>]
311  FlushToWord();
312 
313  // Compute the size of the block, in words, not counting the size field.
314  size_t SizeInWords = GetWordIndex() - B.StartSizeWord - 1;
315  uint64_t BitNo = uint64_t(B.StartSizeWord) * 32;
316 
317  // Update the block size field in the header of this sub-block.
318  BackpatchWord(BitNo, SizeInWords);
319 
320  // Restore the inner block's code size and abbrev table.
321  CurCodeSize = B.PrevCodeSize;
322  CurAbbrevs = std::move(B.PrevAbbrevs);
323  BlockScope.pop_back();
324  FlushToFile();
325  }
326 
327  //===--------------------------------------------------------------------===//
328  // Record Emission
329  //===--------------------------------------------------------------------===//
330 
331 private:
332  /// EmitAbbreviatedLiteral - Emit a literal value according to its abbrev
333  /// record. This is a no-op, since the abbrev specifies the literal to use.
334  template<typename uintty>
335  void EmitAbbreviatedLiteral(const BitCodeAbbrevOp &Op, uintty V) {
336  assert(Op.isLiteral() && "Not a literal");
337  // If the abbrev specifies the literal value to use, don't emit
338  // anything.
339  assert(V == Op.getLiteralValue() &&
340  "Invalid abbrev for record!");
341  }
342 
343  /// EmitAbbreviatedField - Emit a single scalar field value with the specified
344  /// encoding.
345  template<typename uintty>
346  void EmitAbbreviatedField(const BitCodeAbbrevOp &Op, uintty V) {
347  assert(!Op.isLiteral() && "Literals should use EmitAbbreviatedLiteral!");
348 
349  // Encode the value as we are commanded.
350  switch (Op.getEncoding()) {
351  default: llvm_unreachable("Unknown encoding!");
353  if (Op.getEncodingData())
354  Emit((unsigned)V, (unsigned)Op.getEncodingData());
355  break;
357  if (Op.getEncodingData())
358  EmitVBR64(V, (unsigned)Op.getEncodingData());
359  break;
361  Emit(BitCodeAbbrevOp::EncodeChar6((char)V), 6);
362  break;
363  }
364  }
365 
366  /// EmitRecordWithAbbrevImpl - This is the core implementation of the record
367  /// emission code. If BlobData is non-null, then it specifies an array of
368  /// data that should be emitted as part of the Blob or Array operand that is
369  /// known to exist at the end of the record. If Code is specified, then
370  /// it is the record code to emit before the Vals, which must not contain
371  /// the code.
372  template <typename uintty>
373  void EmitRecordWithAbbrevImpl(unsigned Abbrev, ArrayRef<uintty> Vals,
374  StringRef Blob, Optional<unsigned> Code) {
375  const char *BlobData = Blob.data();
376  unsigned BlobLen = (unsigned) Blob.size();
377  unsigned AbbrevNo = Abbrev-bitc::FIRST_APPLICATION_ABBREV;
378  assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
379  const BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo].get();
380 
381  EmitCode(Abbrev);
382 
383  unsigned i = 0, e = static_cast<unsigned>(Abbv->getNumOperandInfos());
384  if (Code) {
385  assert(e && "Expected non-empty abbreviation");
386  const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i++);
387 
388  if (Op.isLiteral())
389  EmitAbbreviatedLiteral(Op, Code.getValue());
390  else {
391  assert(Op.getEncoding() != BitCodeAbbrevOp::Array &&
392  Op.getEncoding() != BitCodeAbbrevOp::Blob &&
393  "Expected literal or scalar");
394  EmitAbbreviatedField(Op, Code.getValue());
395  }
396  }
397 
398  unsigned RecordIdx = 0;
399  for (; i != e; ++i) {
400  const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
401  if (Op.isLiteral()) {
402  assert(RecordIdx < Vals.size() && "Invalid abbrev/record");
403  EmitAbbreviatedLiteral(Op, Vals[RecordIdx]);
404  ++RecordIdx;
405  } else if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
406  // Array case.
407  assert(i + 2 == e && "array op not second to last?");
408  const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
409 
410  // If this record has blob data, emit it, otherwise we must have record
411  // entries to encode this way.
412  if (BlobData) {
413  assert(RecordIdx == Vals.size() &&
414  "Blob data and record entries specified for array!");
415  // Emit a vbr6 to indicate the number of elements present.
416  EmitVBR(static_cast<uint32_t>(BlobLen), 6);
417 
418  // Emit each field.
419  for (unsigned i = 0; i != BlobLen; ++i)
420  EmitAbbreviatedField(EltEnc, (unsigned char)BlobData[i]);
421 
422  // Know that blob data is consumed for assertion below.
423  BlobData = nullptr;
424  } else {
425  // Emit a vbr6 to indicate the number of elements present.
426  EmitVBR(static_cast<uint32_t>(Vals.size()-RecordIdx), 6);
427 
428  // Emit each field.
429  for (unsigned e = Vals.size(); RecordIdx != e; ++RecordIdx)
430  EmitAbbreviatedField(EltEnc, Vals[RecordIdx]);
431  }
432  } else if (Op.getEncoding() == BitCodeAbbrevOp::Blob) {
433  // If this record has blob data, emit it, otherwise we must have record
434  // entries to encode this way.
435 
436  if (BlobData) {
437  assert(RecordIdx == Vals.size() &&
438  "Blob data and record entries specified for blob operand!");
439 
440  assert(Blob.data() == BlobData && "BlobData got moved");
441  assert(Blob.size() == BlobLen && "BlobLen got changed");
442  emitBlob(Blob);
443  BlobData = nullptr;
444  } else {
445  emitBlob(Vals.slice(RecordIdx));
446  }
447  } else { // Single scalar field.
448  assert(RecordIdx < Vals.size() && "Invalid abbrev/record");
449  EmitAbbreviatedField(Op, Vals[RecordIdx]);
450  ++RecordIdx;
451  }
452  }
453  assert(RecordIdx == Vals.size() && "Not all record operands emitted!");
454  assert(BlobData == nullptr &&
455  "Blob data specified for record that doesn't use it!");
456  }
457 
458 public:
459  /// Emit a blob, including flushing before and tail-padding.
460  template <class UIntTy>
461  void emitBlob(ArrayRef<UIntTy> Bytes, bool ShouldEmitSize = true) {
462  // Emit a vbr6 to indicate the number of elements present.
463  if (ShouldEmitSize)
464  EmitVBR(static_cast<uint32_t>(Bytes.size()), 6);
465 
466  // Flush to a 32-bit alignment boundary.
467  FlushToWord();
468 
469  // Emit literal bytes.
470  assert(llvm::all_of(Bytes, [](UIntTy B) { return isUInt<8>(B); }));
471  Out.append(Bytes.begin(), Bytes.end());
472 
473  // Align end to 32-bits.
474  while (GetBufferOffset() & 3)
475  Out.push_back(0);
476  }
477  void emitBlob(StringRef Bytes, bool ShouldEmitSize = true) {
478  emitBlob(makeArrayRef((const uint8_t *)Bytes.data(), Bytes.size()),
479  ShouldEmitSize);
480  }
481 
482  /// EmitRecord - Emit the specified record to the stream, using an abbrev if
483  /// we have one to compress the output.
484  template <typename Container>
485  void EmitRecord(unsigned Code, const Container &Vals, unsigned Abbrev = 0) {
486  if (!Abbrev) {
487  // If we don't have an abbrev to use, emit this in its fully unabbreviated
488  // form.
489  auto Count = static_cast<uint32_t>(makeArrayRef(Vals).size());
491  EmitVBR(Code, 6);
492  EmitVBR(Count, 6);
493  for (unsigned i = 0, e = Count; i != e; ++i)
494  EmitVBR64(Vals[i], 6);
495  return;
496  }
497 
498  EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), StringRef(), Code);
499  }
500 
501  /// EmitRecordWithAbbrev - Emit a record with the specified abbreviation.
502  /// Unlike EmitRecord, the code for the record should be included in Vals as
503  /// the first entry.
504  template <typename Container>
505  void EmitRecordWithAbbrev(unsigned Abbrev, const Container &Vals) {
506  EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), StringRef(), None);
507  }
508 
509  /// EmitRecordWithBlob - Emit the specified record to the stream, using an
510  /// abbrev that includes a blob at the end. The blob data to emit is
511  /// specified by the pointer and length specified at the end. In contrast to
512  /// EmitRecord, this routine expects that the first entry in Vals is the code
513  /// of the record.
514  template <typename Container>
515  void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals,
516  StringRef Blob) {
517  EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), Blob, None);
518  }
519  template <typename Container>
520  void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals,
521  const char *BlobData, unsigned BlobLen) {
522  return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
523  StringRef(BlobData, BlobLen), None);
524  }
525 
526  /// EmitRecordWithArray - Just like EmitRecordWithBlob, works with records
527  /// that end with an array.
528  template <typename Container>
529  void EmitRecordWithArray(unsigned Abbrev, const Container &Vals,
530  StringRef Array) {
531  EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), Array, None);
532  }
533  template <typename Container>
534  void EmitRecordWithArray(unsigned Abbrev, const Container &Vals,
535  const char *ArrayData, unsigned ArrayLen) {
536  return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
537  StringRef(ArrayData, ArrayLen), None);
538  }
539 
540  //===--------------------------------------------------------------------===//
541  // Abbrev Emission
542  //===--------------------------------------------------------------------===//
543 
544 private:
545  // Emit the abbreviation as a DEFINE_ABBREV record.
546  void EncodeAbbrev(const BitCodeAbbrev &Abbv) {
548  EmitVBR(Abbv.getNumOperandInfos(), 5);
549  for (unsigned i = 0, e = static_cast<unsigned>(Abbv.getNumOperandInfos());
550  i != e; ++i) {
551  const BitCodeAbbrevOp &Op = Abbv.getOperandInfo(i);
552  Emit(Op.isLiteral(), 1);
553  if (Op.isLiteral()) {
554  EmitVBR64(Op.getLiteralValue(), 8);
555  } else {
556  Emit(Op.getEncoding(), 3);
557  if (Op.hasEncodingData())
558  EmitVBR64(Op.getEncodingData(), 5);
559  }
560  }
561  }
562 public:
563 
564  /// Emits the abbreviation \p Abbv to the stream.
565  unsigned EmitAbbrev(std::shared_ptr<BitCodeAbbrev> Abbv) {
566  EncodeAbbrev(*Abbv);
567  CurAbbrevs.push_back(std::move(Abbv));
568  return static_cast<unsigned>(CurAbbrevs.size())-1 +
570  }
571 
572  //===--------------------------------------------------------------------===//
573  // BlockInfo Block Emission
574  //===--------------------------------------------------------------------===//
575 
576  /// EnterBlockInfoBlock - Start emitting the BLOCKINFO_BLOCK.
579  BlockInfoCurBID = ~0U;
580  BlockInfoRecords.clear();
581  }
582 private:
583  /// SwitchToBlockID - If we aren't already talking about the specified block
584  /// ID, emit a BLOCKINFO_CODE_SETBID record.
585  void SwitchToBlockID(unsigned BlockID) {
586  if (BlockInfoCurBID == BlockID) return;
588  V.push_back(BlockID);
590  BlockInfoCurBID = BlockID;
591  }
592 
593  BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
594  if (BlockInfo *BI = getBlockInfo(BlockID))
595  return *BI;
596 
597  // Otherwise, add a new record.
598  BlockInfoRecords.emplace_back();
599  BlockInfoRecords.back().BlockID = BlockID;
600  return BlockInfoRecords.back();
601  }
602 
603 public:
604 
605  /// EmitBlockInfoAbbrev - Emit a DEFINE_ABBREV record for the specified
606  /// BlockID.
607  unsigned EmitBlockInfoAbbrev(unsigned BlockID, std::shared_ptr<BitCodeAbbrev> Abbv) {
608  SwitchToBlockID(BlockID);
609  EncodeAbbrev(*Abbv);
610 
611  // Add the abbrev to the specified block record.
612  BlockInfo &Info = getOrCreateBlockInfo(BlockID);
613  Info.Abbrevs.push_back(std::move(Abbv));
614 
615  return Info.Abbrevs.size()-1+bitc::FIRST_APPLICATION_ABBREV;
616  }
617 };
618 
619 
620 } // End llvm namespace
621 
622 #endif
i
i
Definition: README.txt:29
llvm::BitstreamWriter::EmitVBR64
void EmitVBR64(uint64_t Val, unsigned NumBits)
Definition: BitstreamWriter.h:237
llvm::BitCodeAbbrev::getNumOperandInfos
unsigned getNumOperandInfos() const
Definition: BitCodes.h:112
llvm::BitstreamWriter::emitBlob
void emitBlob(ArrayRef< UIntTy > Bytes, bool ShouldEmitSize=true)
Emit a blob, including flushing before and tail-padding.
Definition: BitstreamWriter.h:461
llvm::BitstreamWriter::FlushToWord
void FlushToWord()
Definition: BitstreamWriter.h:216
llvm::BitstreamWriter::EmitRecordWithBlob
void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals, StringRef Blob)
EmitRecordWithBlob - Emit the specified record to the stream, using an abbrev that includes a blob at...
Definition: BitstreamWriter.h:515
MathExtras.h
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
Optional.h
StringRef.h
llvm::BitCodeAbbrevOp::Fixed
@ Fixed
Definition: BitCodes.h:39
llvm::SmallVector< unsigned, 2 >
llvm::tgtok::Code
@ Code
Definition: TGLexer.h:50
llvm::bitc::DEFINE_ABBREV
@ DEFINE_ABBREV
DEFINE_ABBREV - Defines an abbrev for the current block.
Definition: BitCodeEnums.h:53
llvm::BitstreamWriter::EmitVBR
void EmitVBR(uint32_t Val, unsigned NumBits)
Definition: BitstreamWriter.h:224
llvm::BitstreamWriter::EmitRecord
void EmitRecord(unsigned Code, const Container &Vals, unsigned Abbrev=0)
EmitRecord - Emit the specified record to the stream, using an abbrev if we have one to compress the ...
Definition: BitstreamWriter.h:485
llvm::BitstreamWriter::Emit
void Emit(uint32_t Val, unsigned NumBits)
Definition: BitstreamWriter.h:197
llvm::BitstreamWriter::GetAbbrevIDWidth
unsigned GetAbbrevIDWidth() const
Retrieve the number of bits currently used to encode an abbrev ID.
Definition: BitstreamWriter.h:126
llvm::BitstreamWriter::EmitRecordWithArray
void EmitRecordWithArray(unsigned Abbrev, const Container &Vals, const char *ArrayData, unsigned ArrayLen)
Definition: BitstreamWriter.h:534
llvm::bitc::BLOCKINFO_BLOCK_ID
@ BLOCKINFO_BLOCK_ID
BLOCKINFO_BLOCK is used to define metadata about blocks, for example, standard abbrevs that should be...
Definition: BitCodeEnums.h:69
llvm::bitc::BlockIDWidth
@ BlockIDWidth
Definition: BitCodeEnums.h:37
llvm::BitstreamWriter::BackpatchWord64
void BackpatchWord64(uint64_t BitNo, uint64_t Val)
Definition: BitstreamWriter.h:192
llvm::bitc::ENTER_SUBBLOCK
@ ENTER_SUBBLOCK
Definition: BitCodeEnums.h:46
llvm::BitstreamWriter::EnterSubblock
void EnterSubblock(unsigned BlockID, unsigned CodeLen)
Definition: BitstreamWriter.h:277
llvm::all_of
bool all_of(R &&range, UnaryPredicate P)
Provide wrappers to std::all_of which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1617
llvm::BitCodeAbbrevOp::Char6
@ Char6
Definition: BitCodes.h:42
llvm::SmallVectorImpl::append
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:667
llvm::BitstreamWriter::GetCurrentBitNo
uint64_t GetCurrentBitNo() const
Retrieve the current position in the stream, in bits.
Definition: BitstreamWriter.h:123
llvm::BitstreamWriter::getBlockInfo
BlockInfo * getBlockInfo(unsigned BlockID)
getBlockInfo - If there is block info for the specified ID, return it, otherwise return null.
Definition: BitstreamWriter.h:265
llvm::BitstreamWriter::~BitstreamWriter
~BitstreamWriter()
Definition: BitstreamWriter.h:117
llvm::bitc::END_BLOCK
@ END_BLOCK
Definition: BitCodeEnums.h:45
B
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
llvm::BitstreamWriter
Definition: BitstreamWriter.h:30
llvm::BitstreamWriter::EmitAbbrev
unsigned EmitAbbrev(std::shared_ptr< BitCodeAbbrev > Abbv)
Emits the abbreviation Abbv to the stream.
Definition: BitstreamWriter.h:565
llvm::BitstreamWriter::EmitRecordWithArray
void EmitRecordWithArray(unsigned Abbrev, const Container &Vals, StringRef Array)
EmitRecordWithArray - Just like EmitRecordWithBlob, works with records that end with an array.
Definition: BitstreamWriter.h:529
Info
Analysis containing CSE Info
Definition: CSEInfo.cpp:27
llvm::BitstreamWriter::EmitRecordWithBlob
void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals, const char *BlobData, unsigned BlobLen)
Definition: BitstreamWriter.h:520
llvm::BitstreamWriter::EmitBlockInfoAbbrev
unsigned EmitBlockInfoAbbrev(unsigned BlockID, std::shared_ptr< BitCodeAbbrev > Abbv)
EmitBlockInfoAbbrev - Emit a DEFINE_ABBREV record for the specified BlockID.
Definition: BitstreamWriter.h:607
llvm::BitstreamWriter::emitBlob
void emitBlob(StringRef Bytes, bool ShouldEmitSize=true)
Definition: BitstreamWriter.h:477
llvm::BitCodeAbbrevOp::Blob
@ Blob
Definition: BitCodes.h:43
llvm::None
const NoneType None
Definition: None.h:24
llvm::RISCVFenceField::O
@ O
Definition: RISCVBaseInfo.h:240
uint64_t
llvm::BitstreamWriter::EnterBlockInfoBlock
void EnterBlockInfoBlock()
EnterBlockInfoBlock - Start emitting the BLOCKINFO_BLOCK.
Definition: BitstreamWriter.h:577
llvm::bitc::BlockSizeWidth
@ BlockSizeWidth
Definition: BitCodeEnums.h:39
move
compiles ldr LCPI1_0 ldr ldr mov lsr tst moveq r1 ldr LCPI1_1 and r0 bx lr It would be better to do something like to fold the shift into the conditional move
Definition: README.txt:546
llvm::numbers::e
constexpr double e
Definition: MathExtras.h:57
llvm::BitstreamWriter::BitstreamWriter
BitstreamWriter(SmallVectorImpl< char > &O, raw_fd_stream *FS=nullptr, uint32_t FlushThreshold=512)
Create a BitstreamWriter that writes to Buffer O.
Definition: BitstreamWriter.h:112
ArrayRef.h
llvm::BitCodeAbbrevOp::VBR
@ VBR
Definition: BitCodes.h:40
llvm::BitCodeAbbrevOp::Array
@ Array
Definition: BitCodes.h:41
llvm::BitstreamWriter::ExitBlock
void ExitBlock()
Definition: BitstreamWriter.h:304
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
llvm::isUInt< 8 >
constexpr bool isUInt< 8 >(uint64_t x)
Definition: MathExtras.h:405
llvm::bitc::BLOCKINFO_CODE_SETBID
@ BLOCKINFO_CODE_SETBID
Definition: BitCodeEnums.h:81
llvm::BitCodeAbbrev::getOperandInfo
const BitCodeAbbrevOp & getOperandInfo(unsigned N) const
Definition: BitCodes.h:115
llvm::ArrayRef
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: APInt.h:32
BitCodes.h
llvm::min
Expected< ExpressionValue > min(const ExpressionValue &Lhs, const ExpressionValue &Rhs)
Definition: FileCheck.cpp:357
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:58
llvm_unreachable
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:143
uint32_t
llvm::append_range
void append_range(Container &C, Range &&R)
Wrapper function to append a range to a container.
Definition: STLExtras.h:1823
llvm::BitstreamWriter::EmitCode
void EmitCode(unsigned Val)
EmitCode - Emit the specified code.
Definition: BitstreamWriter.h:255
llvm::StringRef::size
constexpr LLVM_NODISCARD size_t size() const
size - Get the string size.
Definition: StringRef.h:157
llvm::bitc::UNABBREV_RECORD
@ UNABBREV_RECORD
Definition: BitCodeEnums.h:57
llvm::bitc::FIRST_APPLICATION_ABBREV
@ FIRST_APPLICATION_ABBREV
Definition: BitCodeEnums.h:60
llvm::AMDGPU::SendMsg::Op
Op
Definition: SIDefines.h:348
llvm::ArrayRef::begin
iterator begin() const
Definition: ArrayRef.h:152
llvm::BitstreamWriter::BackpatchWord
void BackpatchWord(uint64_t BitNo, unsigned NewWord)
Backpatch a 32-bit word in the output at the given bit offset with the specified value.
Definition: BitstreamWriter.h:134
llvm::support
Definition: Endian.h:25
llvm::BitstreamWriter::EmitRecordWithAbbrev
void EmitRecordWithAbbrev(unsigned Abbrev, const Container &Vals)
EmitRecordWithAbbrev - Emit a record with the specified abbreviation.
Definition: BitstreamWriter.h:505
llvm::SmallVectorImpl::clear
void clear()
Definition: SmallVector.h:591
llvm::makeArrayRef
ArrayRef< T > makeArrayRef(const T &OneElt)
Construct an ArrayRef from a single element.
Definition: ArrayRef.h:475
llvm::BitCodeAbbrevOp
BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
Definition: BitCodes.h:33
llvm::BitCodeAbbrev
BitCodeAbbrev - This class represents an abbreviation record.
Definition: BitCodes.h:103
SmallVector.h
llvm::raw_fd_stream
A raw_ostream of a file for reading/writing/seeking.
Definition: raw_ostream.h:601
llvm::ArrayRef::size
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:164
llvm::StringRef::data
const LLVM_NODISCARD char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:149
llvm::SmallVectorImpl< char >
llvm::bitc::CodeLenWidth
@ CodeLenWidth
Definition: BitCodeEnums.h:38
raw_ostream.h
Endian.h
llvm::BitCodeAbbrevOp::EncodeChar6
static unsigned EncodeChar6(char C)
Definition: BitCodes.h:83
llvm::Value
LLVM Value Representation.
Definition: Value.h:74
llvm::ArrayRef::end
iterator end() const
Definition: ArrayRef.h:153