| //===- BitstreamWriter.h - Low-level bitstream writer interface -*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This header defines the BitstreamWriter class. This class can be used to |
| // write an arbitrary bitstream, regardless of its contents. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_BITSTREAM_BITSTREAMWRITER_H |
| #define LLVM_BITSTREAM_BITSTREAMWRITER_H |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/Bitstream/BitCodes.h" |
| #include "llvm/Support/Endian.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <algorithm> |
| #include <optional> |
| #include <vector> |
| |
| namespace llvm { |
| |
| class BitstreamWriter { |
| /// Out - The buffer that keeps unflushed bytes. |
| SmallVectorImpl<char> &Out; |
| |
| /// FS - The file stream that Out flushes to. If FS is nullptr, it does not |
| /// support read or seek, Out cannot be flushed until all data are written. |
| raw_fd_stream *FS; |
| |
| /// FlushThreshold - If FS is valid, this is the threshold (unit B) to flush |
| /// FS. |
| const uint64_t FlushThreshold; |
| |
| /// CurBit - Always between 0 and 31 inclusive, specifies the next bit to use. |
| unsigned CurBit; |
| |
| /// CurValue - The current value. Only bits < CurBit are valid. |
| uint32_t CurValue; |
| |
| /// CurCodeSize - This is the declared size of code values used for the |
| /// current block, in bits. |
| unsigned CurCodeSize; |
| |
| /// BlockInfoCurBID - When emitting a BLOCKINFO_BLOCK, this is the currently |
| /// selected BLOCK ID. |
| unsigned BlockInfoCurBID; |
| |
| /// CurAbbrevs - Abbrevs installed at in this block. |
| std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs; |
| |
| struct Block { |
| unsigned PrevCodeSize; |
| size_t StartSizeWord; |
| std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs; |
| Block(unsigned PCS, size_t SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {} |
| }; |
| |
| /// BlockScope - This tracks the current blocks that we have entered. |
| std::vector<Block> BlockScope; |
| |
| /// BlockInfo - This contains information emitted to BLOCKINFO_BLOCK blocks. |
| /// These describe abbreviations that all blocks of the specified ID inherit. |
| struct BlockInfo { |
| unsigned BlockID; |
| std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs; |
| }; |
| std::vector<BlockInfo> BlockInfoRecords; |
| |
| void WriteWord(unsigned Value) { |
| Value = support::endian::byte_swap<uint32_t, support::little>(Value); |
| Out.append(reinterpret_cast<const char *>(&Value), |
| reinterpret_cast<const char *>(&Value + 1)); |
| } |
| |
| uint64_t GetNumOfFlushedBytes() const { return FS ? FS->tell() : 0; } |
| |
| size_t GetBufferOffset() const { return Out.size() + GetNumOfFlushedBytes(); } |
| |
| size_t GetWordIndex() const { |
| size_t Offset = GetBufferOffset(); |
| assert((Offset & 3) == 0 && "Not 32-bit aligned"); |
| return Offset / 4; |
| } |
| |
| /// If the related file stream supports reading, seeking and writing, flush |
| /// the buffer if its size is above a threshold. |
| void FlushToFile() { |
| if (!FS) |
| return; |
| if (Out.size() < FlushThreshold) |
| return; |
| FS->write((char *)&Out.front(), Out.size()); |
| Out.clear(); |
| } |
| |
| public: |
| /// Create a BitstreamWriter that writes to Buffer \p O. |
| /// |
| /// \p FS is the file stream that \p O flushes to incrementally. If \p FS is |
| /// null, \p O does not flush incrementially, but writes to disk at the end. |
| /// |
| /// \p FlushThreshold is the threshold (unit M) to flush \p O if \p FS is |
| /// valid. Flushing only occurs at (sub)block boundaries. |
| BitstreamWriter(SmallVectorImpl<char> &O, raw_fd_stream *FS = nullptr, |
| uint32_t FlushThreshold = 512) |
| : Out(O), FS(FS), FlushThreshold(FlushThreshold << 20), CurBit(0), |
| CurValue(0), CurCodeSize(2) {} |
| |
| ~BitstreamWriter() { |
| assert(CurBit == 0 && "Unflushed data remaining"); |
| assert(BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance"); |
| } |
| |
| /// Retrieve the current position in the stream, in bits. |
| uint64_t GetCurrentBitNo() const { return GetBufferOffset() * 8 + CurBit; } |
| |
| /// Retrieve the number of bits currently used to encode an abbrev ID. |
| unsigned GetAbbrevIDWidth() const { return CurCodeSize; } |
| |
| //===--------------------------------------------------------------------===// |
| // Basic Primitives for emitting bits to the stream. |
| //===--------------------------------------------------------------------===// |
| |
| /// Backpatch a 32-bit word in the output at the given bit offset |
| /// with the specified value. |
| void BackpatchWord(uint64_t BitNo, unsigned NewWord) { |
| using namespace llvm::support; |
| uint64_t ByteNo = BitNo / 8; |
| uint64_t StartBit = BitNo & 7; |
| uint64_t NumOfFlushedBytes = GetNumOfFlushedBytes(); |
| |
| if (ByteNo >= NumOfFlushedBytes) { |
| assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>( |
| &Out[ByteNo - NumOfFlushedBytes], StartBit)) && |
| "Expected to be patching over 0-value placeholders"); |
| endian::writeAtBitAlignment<uint32_t, little, unaligned>( |
| &Out[ByteNo - NumOfFlushedBytes], NewWord, StartBit); |
| return; |
| } |
| |
| // If the byte offset to backpatch is flushed, use seek to backfill data. |
| // First, save the file position to restore later. |
| uint64_t CurPos = FS->tell(); |
| |
| // Copy data to update into Bytes from the file FS and the buffer Out. |
| char Bytes[9]; // Use one more byte to silence a warning from Visual C++. |
| size_t BytesNum = StartBit ? 8 : 4; |
| size_t BytesFromDisk = std::min(static_cast<uint64_t>(BytesNum), NumOfFlushedBytes - ByteNo); |
| size_t BytesFromBuffer = BytesNum - BytesFromDisk; |
| |
| // When unaligned, copy existing data into Bytes from the file FS and the |
| // buffer Out so that it can be updated before writing. For debug builds |
| // read bytes unconditionally in order to check that the existing value is 0 |
| // as expected. |
| #ifdef NDEBUG |
| if (StartBit) |
| #endif |
| { |
| FS->seek(ByteNo); |
| ssize_t BytesRead = FS->read(Bytes, BytesFromDisk); |
| (void)BytesRead; // silence warning |
| assert(BytesRead >= 0 && static_cast<size_t>(BytesRead) == BytesFromDisk); |
| for (size_t i = 0; i < BytesFromBuffer; ++i) |
| Bytes[BytesFromDisk + i] = Out[i]; |
| assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>( |
| Bytes, StartBit)) && |
| "Expected to be patching over 0-value placeholders"); |
| } |
| |
| // Update Bytes in terms of bit offset and value. |
| endian::writeAtBitAlignment<uint32_t, little, unaligned>(Bytes, NewWord, |
| StartBit); |
| |
| // Copy updated data back to the file FS and the buffer Out. |
| FS->seek(ByteNo); |
| FS->write(Bytes, BytesFromDisk); |
| for (size_t i = 0; i < BytesFromBuffer; ++i) |
| Out[i] = Bytes[BytesFromDisk + i]; |
| |
| // Restore the file position. |
| FS->seek(CurPos); |
| } |
| |
| void BackpatchWord64(uint64_t BitNo, uint64_t Val) { |
| BackpatchWord(BitNo, (uint32_t)Val); |
| BackpatchWord(BitNo + 32, (uint32_t)(Val >> 32)); |
| } |
| |
| void Emit(uint32_t Val, unsigned NumBits) { |
| assert(NumBits && NumBits <= 32 && "Invalid value size!"); |
| assert((Val & ~(~0U >> (32-NumBits))) == 0 && "High bits set!"); |
| CurValue |= Val << CurBit; |
| if (CurBit + NumBits < 32) { |
| CurBit += NumBits; |
| return; |
| } |
| |
| // Add the current word. |
| WriteWord(CurValue); |
| |
| if (CurBit) |
| CurValue = Val >> (32-CurBit); |
| else |
| CurValue = 0; |
| CurBit = (CurBit+NumBits) & 31; |
| } |
| |
| void FlushToWord() { |
| if (CurBit) { |
| WriteWord(CurValue); |
| CurBit = 0; |
| CurValue = 0; |
| } |
| } |
| |
| void EmitVBR(uint32_t Val, unsigned NumBits) { |
| assert(NumBits <= 32 && "Too many bits to emit!"); |
| uint32_t Threshold = 1U << (NumBits-1); |
| |
| // Emit the bits with VBR encoding, NumBits-1 bits at a time. |
| while (Val >= Threshold) { |
| Emit((Val & ((1 << (NumBits-1))-1)) | (1 << (NumBits-1)), NumBits); |
| Val >>= NumBits-1; |
| } |
| |
| Emit(Val, NumBits); |
| } |
| |
| void EmitVBR64(uint64_t Val, unsigned NumBits) { |
| assert(NumBits <= 32 && "Too many bits to emit!"); |
| if ((uint32_t)Val == Val) |
| return EmitVBR((uint32_t)Val, NumBits); |
| |
| uint32_t Threshold = 1U << (NumBits-1); |
| |
| // Emit the bits with VBR encoding, NumBits-1 bits at a time. |
| while (Val >= Threshold) { |
| Emit(((uint32_t)Val & ((1 << (NumBits - 1)) - 1)) | (1 << (NumBits - 1)), |
| NumBits); |
| Val >>= NumBits-1; |
| } |
| |
| Emit((uint32_t)Val, NumBits); |
| } |
| |
| /// EmitCode - Emit the specified code. |
| void EmitCode(unsigned Val) { |
| Emit(Val, CurCodeSize); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Block Manipulation |
| //===--------------------------------------------------------------------===// |
| |
| /// getBlockInfo - If there is block info for the specified ID, return it, |
| /// otherwise return null. |
| BlockInfo *getBlockInfo(unsigned BlockID) { |
| // Common case, the most recent entry matches BlockID. |
| if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID) |
| return &BlockInfoRecords.back(); |
| |
| for (BlockInfo &BI : BlockInfoRecords) |
| if (BI.BlockID == BlockID) |
| return &BI; |
| return nullptr; |
| } |
| |
| void EnterSubblock(unsigned BlockID, unsigned CodeLen) { |
| // Block header: |
| // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen] |
| EmitCode(bitc::ENTER_SUBBLOCK); |
| EmitVBR(BlockID, bitc::BlockIDWidth); |
| EmitVBR(CodeLen, bitc::CodeLenWidth); |
| FlushToWord(); |
| |
| size_t BlockSizeWordIndex = GetWordIndex(); |
| unsigned OldCodeSize = CurCodeSize; |
| |
| // Emit a placeholder, which will be replaced when the block is popped. |
| Emit(0, bitc::BlockSizeWidth); |
| |
| CurCodeSize = CodeLen; |
| |
| // Push the outer block's abbrev set onto the stack, start out with an |
| // empty abbrev set. |
| BlockScope.emplace_back(OldCodeSize, BlockSizeWordIndex); |
| BlockScope.back().PrevAbbrevs.swap(CurAbbrevs); |
| |
| // If there is a blockinfo for this BlockID, add all the predefined abbrevs |
| // to the abbrev list. |
| if (BlockInfo *Info = getBlockInfo(BlockID)) |
| append_range(CurAbbrevs, Info->Abbrevs); |
| } |
| |
| void ExitBlock() { |
| assert(!BlockScope.empty() && "Block scope imbalance!"); |
| const Block &B = BlockScope.back(); |
| |
| // Block tail: |
| // [END_BLOCK, <align4bytes>] |
| EmitCode(bitc::END_BLOCK); |
| FlushToWord(); |
| |
| // Compute the size of the block, in words, not counting the size field. |
| size_t SizeInWords = GetWordIndex() - B.StartSizeWord - 1; |
| uint64_t BitNo = uint64_t(B.StartSizeWord) * 32; |
| |
| // Update the block size field in the header of this sub-block. |
| BackpatchWord(BitNo, SizeInWords); |
| |
| // Restore the inner block's code size and abbrev table. |
| CurCodeSize = B.PrevCodeSize; |
| CurAbbrevs = std::move(B.PrevAbbrevs); |
| BlockScope.pop_back(); |
| FlushToFile(); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Record Emission |
| //===--------------------------------------------------------------------===// |
| |
| private: |
| /// EmitAbbreviatedLiteral - Emit a literal value according to its abbrev |
| /// record. This is a no-op, since the abbrev specifies the literal to use. |
| template<typename uintty> |
| void EmitAbbreviatedLiteral(const BitCodeAbbrevOp &Op, uintty V) { |
| assert(Op.isLiteral() && "Not a literal"); |
| // If the abbrev specifies the literal value to use, don't emit |
| // anything. |
| assert(V == Op.getLiteralValue() && |
| "Invalid abbrev for record!"); |
| } |
| |
| /// EmitAbbreviatedField - Emit a single scalar field value with the specified |
| /// encoding. |
| template<typename uintty> |
| void EmitAbbreviatedField(const BitCodeAbbrevOp &Op, uintty V) { |
| assert(!Op.isLiteral() && "Literals should use EmitAbbreviatedLiteral!"); |
| |
| // Encode the value as we are commanded. |
| switch (Op.getEncoding()) { |
| default: llvm_unreachable("Unknown encoding!"); |
| case BitCodeAbbrevOp::Fixed: |
| if (Op.getEncodingData()) |
| Emit((unsigned)V, (unsigned)Op.getEncodingData()); |
| break; |
| case BitCodeAbbrevOp::VBR: |
| if (Op.getEncodingData()) |
| EmitVBR64(V, (unsigned)Op.getEncodingData()); |
| break; |
| case BitCodeAbbrevOp::Char6: |
| Emit(BitCodeAbbrevOp::EncodeChar6((char)V), 6); |
| break; |
| } |
| } |
| |
| /// EmitRecordWithAbbrevImpl - This is the core implementation of the record |
| /// emission code. If BlobData is non-null, then it specifies an array of |
| /// data that should be emitted as part of the Blob or Array operand that is |
| /// known to exist at the end of the record. If Code is specified, then |
| /// it is the record code to emit before the Vals, which must not contain |
| /// the code. |
| template <typename uintty> |
| void EmitRecordWithAbbrevImpl(unsigned Abbrev, ArrayRef<uintty> Vals, |
| StringRef Blob, std::optional<unsigned> Code) { |
| const char *BlobData = Blob.data(); |
| unsigned BlobLen = (unsigned) Blob.size(); |
| unsigned AbbrevNo = Abbrev-bitc::FIRST_APPLICATION_ABBREV; |
| assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!"); |
| const BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo].get(); |
| |
| EmitCode(Abbrev); |
| |
| unsigned i = 0, e = static_cast<unsigned>(Abbv->getNumOperandInfos()); |
| if (Code) { |
| assert(e && "Expected non-empty abbreviation"); |
| const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i++); |
| |
| if (Op.isLiteral()) |
| EmitAbbreviatedLiteral(Op, *Code); |
| else { |
| assert(Op.getEncoding() != BitCodeAbbrevOp::Array && |
| Op.getEncoding() != BitCodeAbbrevOp::Blob && |
| "Expected literal or scalar"); |
| EmitAbbreviatedField(Op, *Code); |
| } |
| } |
| |
| unsigned RecordIdx = 0; |
| for (; i != e; ++i) { |
| const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i); |
| if (Op.isLiteral()) { |
| assert(RecordIdx < Vals.size() && "Invalid abbrev/record"); |
| EmitAbbreviatedLiteral(Op, Vals[RecordIdx]); |
| ++RecordIdx; |
| } else if (Op.getEncoding() == BitCodeAbbrevOp::Array) { |
| // Array case. |
| assert(i + 2 == e && "array op not second to last?"); |
| const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i); |
| |
| // If this record has blob data, emit it, otherwise we must have record |
| // entries to encode this way. |
| if (BlobData) { |
| assert(RecordIdx == Vals.size() && |
| "Blob data and record entries specified for array!"); |
| // Emit a vbr6 to indicate the number of elements present. |
| EmitVBR(static_cast<uint32_t>(BlobLen), 6); |
| |
| // Emit each field. |
| for (unsigned i = 0; i != BlobLen; ++i) |
| EmitAbbreviatedField(EltEnc, (unsigned char)BlobData[i]); |
| |
| // Know that blob data is consumed for assertion below. |
| BlobData = nullptr; |
| } else { |
| // Emit a vbr6 to indicate the number of elements present. |
| EmitVBR(static_cast<uint32_t>(Vals.size()-RecordIdx), 6); |
| |
| // Emit each field. |
| for (unsigned e = Vals.size(); RecordIdx != e; ++RecordIdx) |
| EmitAbbreviatedField(EltEnc, Vals[RecordIdx]); |
| } |
| } else if (Op.getEncoding() == BitCodeAbbrevOp::Blob) { |
| // If this record has blob data, emit it, otherwise we must have record |
| // entries to encode this way. |
| |
| if (BlobData) { |
| assert(RecordIdx == Vals.size() && |
| "Blob data and record entries specified for blob operand!"); |
| |
| assert(Blob.data() == BlobData && "BlobData got moved"); |
| assert(Blob.size() == BlobLen && "BlobLen got changed"); |
| emitBlob(Blob); |
| BlobData = nullptr; |
| } else { |
| emitBlob(Vals.slice(RecordIdx)); |
| } |
| } else { // Single scalar field. |
| assert(RecordIdx < Vals.size() && "Invalid abbrev/record"); |
| EmitAbbreviatedField(Op, Vals[RecordIdx]); |
| ++RecordIdx; |
| } |
| } |
| assert(RecordIdx == Vals.size() && "Not all record operands emitted!"); |
| assert(BlobData == nullptr && |
| "Blob data specified for record that doesn't use it!"); |
| } |
| |
| public: |
| /// Emit a blob, including flushing before and tail-padding. |
| template <class UIntTy> |
| void emitBlob(ArrayRef<UIntTy> Bytes, bool ShouldEmitSize = true) { |
| // Emit a vbr6 to indicate the number of elements present. |
| if (ShouldEmitSize) |
| EmitVBR(static_cast<uint32_t>(Bytes.size()), 6); |
| |
| // Flush to a 32-bit alignment boundary. |
| FlushToWord(); |
| |
| // Emit literal bytes. |
| assert(llvm::all_of(Bytes, [](UIntTy B) { return isUInt<8>(B); })); |
| Out.append(Bytes.begin(), Bytes.end()); |
| |
| // Align end to 32-bits. |
| while (GetBufferOffset() & 3) |
| Out.push_back(0); |
| } |
| void emitBlob(StringRef Bytes, bool ShouldEmitSize = true) { |
| emitBlob(ArrayRef((const uint8_t *)Bytes.data(), Bytes.size()), |
| ShouldEmitSize); |
| } |
| |
| /// EmitRecord - Emit the specified record to the stream, using an abbrev if |
| /// we have one to compress the output. |
| template <typename Container> |
| void EmitRecord(unsigned Code, const Container &Vals, unsigned Abbrev = 0) { |
| if (!Abbrev) { |
| // If we don't have an abbrev to use, emit this in its fully unabbreviated |
| // form. |
| auto Count = static_cast<uint32_t>(std::size(Vals)); |
| EmitCode(bitc::UNABBREV_RECORD); |
| EmitVBR(Code, 6); |
| EmitVBR(Count, 6); |
| for (unsigned i = 0, e = Count; i != e; ++i) |
| EmitVBR64(Vals[i], 6); |
| return; |
| } |
| |
| EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), StringRef(), Code); |
| } |
| |
| /// EmitRecordWithAbbrev - Emit a record with the specified abbreviation. |
| /// Unlike EmitRecord, the code for the record should be included in Vals as |
| /// the first entry. |
| template <typename Container> |
| void EmitRecordWithAbbrev(unsigned Abbrev, const Container &Vals) { |
| EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), StringRef(), std::nullopt); |
| } |
| |
| /// EmitRecordWithBlob - Emit the specified record to the stream, using an |
| /// abbrev that includes a blob at the end. The blob data to emit is |
| /// specified by the pointer and length specified at the end. In contrast to |
| /// EmitRecord, this routine expects that the first entry in Vals is the code |
| /// of the record. |
| template <typename Container> |
| void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals, |
| StringRef Blob) { |
| EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), Blob, std::nullopt); |
| } |
| template <typename Container> |
| void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals, |
| const char *BlobData, unsigned BlobLen) { |
| return EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), |
| StringRef(BlobData, BlobLen), std::nullopt); |
| } |
| |
| /// EmitRecordWithArray - Just like EmitRecordWithBlob, works with records |
| /// that end with an array. |
| template <typename Container> |
| void EmitRecordWithArray(unsigned Abbrev, const Container &Vals, |
| StringRef Array) { |
| EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), Array, std::nullopt); |
| } |
| template <typename Container> |
| void EmitRecordWithArray(unsigned Abbrev, const Container &Vals, |
| const char *ArrayData, unsigned ArrayLen) { |
| return EmitRecordWithAbbrevImpl( |
| Abbrev, ArrayRef(Vals), StringRef(ArrayData, ArrayLen), std::nullopt); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Abbrev Emission |
| //===--------------------------------------------------------------------===// |
| |
| private: |
| // Emit the abbreviation as a DEFINE_ABBREV record. |
| void EncodeAbbrev(const BitCodeAbbrev &Abbv) { |
| EmitCode(bitc::DEFINE_ABBREV); |
| EmitVBR(Abbv.getNumOperandInfos(), 5); |
| for (unsigned i = 0, e = static_cast<unsigned>(Abbv.getNumOperandInfos()); |
| i != e; ++i) { |
| const BitCodeAbbrevOp &Op = Abbv.getOperandInfo(i); |
| Emit(Op.isLiteral(), 1); |
| if (Op.isLiteral()) { |
| EmitVBR64(Op.getLiteralValue(), 8); |
| } else { |
| Emit(Op.getEncoding(), 3); |
| if (Op.hasEncodingData()) |
| EmitVBR64(Op.getEncodingData(), 5); |
| } |
| } |
| } |
| public: |
| |
| /// Emits the abbreviation \p Abbv to the stream. |
| unsigned EmitAbbrev(std::shared_ptr<BitCodeAbbrev> Abbv) { |
| EncodeAbbrev(*Abbv); |
| CurAbbrevs.push_back(std::move(Abbv)); |
| return static_cast<unsigned>(CurAbbrevs.size())-1 + |
| bitc::FIRST_APPLICATION_ABBREV; |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // BlockInfo Block Emission |
| //===--------------------------------------------------------------------===// |
| |
| /// EnterBlockInfoBlock - Start emitting the BLOCKINFO_BLOCK. |
| void EnterBlockInfoBlock() { |
| EnterSubblock(bitc::BLOCKINFO_BLOCK_ID, 2); |
| BlockInfoCurBID = ~0U; |
| BlockInfoRecords.clear(); |
| } |
| private: |
| /// SwitchToBlockID - If we aren't already talking about the specified block |
| /// ID, emit a BLOCKINFO_CODE_SETBID record. |
| void SwitchToBlockID(unsigned BlockID) { |
| if (BlockInfoCurBID == BlockID) return; |
| SmallVector<unsigned, 2> V; |
| V.push_back(BlockID); |
| EmitRecord(bitc::BLOCKINFO_CODE_SETBID, V); |
| BlockInfoCurBID = BlockID; |
| } |
| |
| BlockInfo &getOrCreateBlockInfo(unsigned BlockID) { |
| if (BlockInfo *BI = getBlockInfo(BlockID)) |
| return *BI; |
| |
| // Otherwise, add a new record. |
| BlockInfoRecords.emplace_back(); |
| BlockInfoRecords.back().BlockID = BlockID; |
| return BlockInfoRecords.back(); |
| } |
| |
| public: |
| |
| /// EmitBlockInfoAbbrev - Emit a DEFINE_ABBREV record for the specified |
| /// BlockID. |
| unsigned EmitBlockInfoAbbrev(unsigned BlockID, std::shared_ptr<BitCodeAbbrev> Abbv) { |
| SwitchToBlockID(BlockID); |
| EncodeAbbrev(*Abbv); |
| |
| // Add the abbrev to the specified block record. |
| BlockInfo &Info = getOrCreateBlockInfo(BlockID); |
| Info.Abbrevs.push_back(std::move(Abbv)); |
| |
| return Info.Abbrevs.size()-1+bitc::FIRST_APPLICATION_ABBREV; |
| } |
| }; |
| |
| |
| } // End llvm namespace |
| |
| #endif |