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14 | pmbaty | 1 | //===- BitstreamWriter.h - Low-level bitstream writer interface -*- C++ -*-===// |
2 | // |
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3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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4 | // See https://llvm.org/LICENSE.txt for license information. |
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5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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6 | // |
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7 | //===----------------------------------------------------------------------===// |
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8 | // |
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9 | // This header defines the BitstreamWriter class. This class can be used to |
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10 | // write an arbitrary bitstream, regardless of its contents. |
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11 | // |
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12 | //===----------------------------------------------------------------------===// |
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13 | |||
14 | #ifndef LLVM_BITSTREAM_BITSTREAMWRITER_H |
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15 | #define LLVM_BITSTREAM_BITSTREAMWRITER_H |
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16 | |||
17 | #include "llvm/ADT/ArrayRef.h" |
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18 | #include "llvm/ADT/SmallVector.h" |
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19 | #include "llvm/ADT/StringRef.h" |
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20 | #include "llvm/Bitstream/BitCodes.h" |
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21 | #include "llvm/Support/Endian.h" |
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22 | #include "llvm/Support/MathExtras.h" |
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23 | #include "llvm/Support/raw_ostream.h" |
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24 | #include <algorithm> |
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25 | #include <optional> |
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26 | #include <vector> |
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27 | |||
28 | namespace llvm { |
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29 | |||
30 | class BitstreamWriter { |
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31 | /// Out - The buffer that keeps unflushed bytes. |
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32 | SmallVectorImpl<char> &Out; |
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33 | |||
34 | /// FS - The file stream that Out flushes to. If FS is nullptr, it does not |
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35 | /// support read or seek, Out cannot be flushed until all data are written. |
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36 | raw_fd_stream *FS; |
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37 | |||
38 | /// FlushThreshold - If FS is valid, this is the threshold (unit B) to flush |
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39 | /// FS. |
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40 | const uint64_t FlushThreshold; |
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41 | |||
42 | /// CurBit - Always between 0 and 31 inclusive, specifies the next bit to use. |
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43 | unsigned CurBit; |
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44 | |||
45 | /// CurValue - The current value. Only bits < CurBit are valid. |
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46 | uint32_t CurValue; |
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47 | |||
48 | /// CurCodeSize - This is the declared size of code values used for the |
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49 | /// current block, in bits. |
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50 | unsigned CurCodeSize; |
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51 | |||
52 | /// BlockInfoCurBID - When emitting a BLOCKINFO_BLOCK, this is the currently |
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53 | /// selected BLOCK ID. |
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54 | unsigned BlockInfoCurBID; |
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55 | |||
56 | /// CurAbbrevs - Abbrevs installed at in this block. |
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57 | std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs; |
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58 | |||
59 | struct Block { |
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60 | unsigned PrevCodeSize; |
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61 | size_t StartSizeWord; |
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62 | std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs; |
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63 | Block(unsigned PCS, size_t SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {} |
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64 | }; |
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65 | |||
66 | /// BlockScope - This tracks the current blocks that we have entered. |
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67 | std::vector<Block> BlockScope; |
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68 | |||
69 | /// BlockInfo - This contains information emitted to BLOCKINFO_BLOCK blocks. |
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70 | /// These describe abbreviations that all blocks of the specified ID inherit. |
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71 | struct BlockInfo { |
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72 | unsigned BlockID; |
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73 | std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs; |
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74 | }; |
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75 | std::vector<BlockInfo> BlockInfoRecords; |
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76 | |||
77 | void WriteWord(unsigned Value) { |
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78 | Value = support::endian::byte_swap<uint32_t, support::little>(Value); |
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79 | Out.append(reinterpret_cast<const char *>(&Value), |
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80 | reinterpret_cast<const char *>(&Value + 1)); |
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81 | } |
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82 | |||
83 | uint64_t GetNumOfFlushedBytes() const { return FS ? FS->tell() : 0; } |
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84 | |||
85 | size_t GetBufferOffset() const { return Out.size() + GetNumOfFlushedBytes(); } |
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86 | |||
87 | size_t GetWordIndex() const { |
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88 | size_t Offset = GetBufferOffset(); |
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89 | assert((Offset & 3) == 0 && "Not 32-bit aligned"); |
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90 | return Offset / 4; |
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91 | } |
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92 | |||
93 | /// If the related file stream supports reading, seeking and writing, flush |
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94 | /// the buffer if its size is above a threshold. |
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95 | void FlushToFile() { |
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96 | if (!FS) |
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97 | return; |
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98 | if (Out.size() < FlushThreshold) |
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99 | return; |
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100 | FS->write((char *)&Out.front(), Out.size()); |
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101 | Out.clear(); |
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102 | } |
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103 | |||
104 | public: |
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105 | /// Create a BitstreamWriter that writes to Buffer \p O. |
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106 | /// |
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107 | /// \p FS is the file stream that \p O flushes to incrementally. If \p FS is |
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108 | /// null, \p O does not flush incrementially, but writes to disk at the end. |
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109 | /// |
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110 | /// \p FlushThreshold is the threshold (unit M) to flush \p O if \p FS is |
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111 | /// valid. Flushing only occurs at (sub)block boundaries. |
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112 | BitstreamWriter(SmallVectorImpl<char> &O, raw_fd_stream *FS = nullptr, |
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113 | uint32_t FlushThreshold = 512) |
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114 | : Out(O), FS(FS), FlushThreshold(FlushThreshold << 20), CurBit(0), |
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115 | CurValue(0), CurCodeSize(2) {} |
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116 | |||
117 | ~BitstreamWriter() { |
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118 | assert(CurBit == 0 && "Unflushed data remaining"); |
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119 | assert(BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance"); |
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120 | } |
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121 | |||
122 | /// Retrieve the current position in the stream, in bits. |
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123 | uint64_t GetCurrentBitNo() const { return GetBufferOffset() * 8 + CurBit; } |
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124 | |||
125 | /// Retrieve the number of bits currently used to encode an abbrev ID. |
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126 | unsigned GetAbbrevIDWidth() const { return CurCodeSize; } |
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127 | |||
128 | //===--------------------------------------------------------------------===// |
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129 | // Basic Primitives for emitting bits to the stream. |
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130 | //===--------------------------------------------------------------------===// |
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131 | |||
132 | /// Backpatch a 32-bit word in the output at the given bit offset |
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133 | /// with the specified value. |
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134 | void BackpatchWord(uint64_t BitNo, unsigned NewWord) { |
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135 | using namespace llvm::support; |
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136 | uint64_t ByteNo = BitNo / 8; |
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137 | uint64_t StartBit = BitNo & 7; |
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138 | uint64_t NumOfFlushedBytes = GetNumOfFlushedBytes(); |
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139 | |||
140 | if (ByteNo >= NumOfFlushedBytes) { |
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141 | assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>( |
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142 | &Out[ByteNo - NumOfFlushedBytes], StartBit)) && |
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143 | "Expected to be patching over 0-value placeholders"); |
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144 | endian::writeAtBitAlignment<uint32_t, little, unaligned>( |
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145 | &Out[ByteNo - NumOfFlushedBytes], NewWord, StartBit); |
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146 | return; |
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147 | } |
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148 | |||
149 | // If the byte offset to backpatch is flushed, use seek to backfill data. |
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150 | // First, save the file position to restore later. |
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151 | uint64_t CurPos = FS->tell(); |
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152 | |||
153 | // Copy data to update into Bytes from the file FS and the buffer Out. |
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154 | char Bytes[9]; // Use one more byte to silence a warning from Visual C++. |
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155 | size_t BytesNum = StartBit ? 8 : 4; |
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156 | size_t BytesFromDisk = std::min(static_cast<uint64_t>(BytesNum), NumOfFlushedBytes - ByteNo); |
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157 | size_t BytesFromBuffer = BytesNum - BytesFromDisk; |
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158 | |||
159 | // When unaligned, copy existing data into Bytes from the file FS and the |
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160 | // buffer Out so that it can be updated before writing. For debug builds |
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161 | // read bytes unconditionally in order to check that the existing value is 0 |
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162 | // as expected. |
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163 | #ifdef NDEBUG |
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164 | if (StartBit) |
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165 | #endif |
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166 | { |
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167 | FS->seek(ByteNo); |
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168 | ssize_t BytesRead = FS->read(Bytes, BytesFromDisk); |
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169 | (void)BytesRead; // silence warning |
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170 | assert(BytesRead >= 0 && static_cast<size_t>(BytesRead) == BytesFromDisk); |
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171 | for (size_t i = 0; i < BytesFromBuffer; ++i) |
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172 | Bytes[BytesFromDisk + i] = Out[i]; |
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173 | assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>( |
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174 | Bytes, StartBit)) && |
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175 | "Expected to be patching over 0-value placeholders"); |
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176 | } |
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177 | |||
178 | // Update Bytes in terms of bit offset and value. |
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179 | endian::writeAtBitAlignment<uint32_t, little, unaligned>(Bytes, NewWord, |
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180 | StartBit); |
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181 | |||
182 | // Copy updated data back to the file FS and the buffer Out. |
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183 | FS->seek(ByteNo); |
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184 | FS->write(Bytes, BytesFromDisk); |
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185 | for (size_t i = 0; i < BytesFromBuffer; ++i) |
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186 | Out[i] = Bytes[BytesFromDisk + i]; |
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187 | |||
188 | // Restore the file position. |
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189 | FS->seek(CurPos); |
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190 | } |
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191 | |||
192 | void BackpatchWord64(uint64_t BitNo, uint64_t Val) { |
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193 | BackpatchWord(BitNo, (uint32_t)Val); |
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194 | BackpatchWord(BitNo + 32, (uint32_t)(Val >> 32)); |
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195 | } |
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196 | |||
197 | void Emit(uint32_t Val, unsigned NumBits) { |
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198 | assert(NumBits && NumBits <= 32 && "Invalid value size!"); |
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199 | assert((Val & ~(~0U >> (32-NumBits))) == 0 && "High bits set!"); |
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200 | CurValue |= Val << CurBit; |
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201 | if (CurBit + NumBits < 32) { |
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202 | CurBit += NumBits; |
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203 | return; |
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204 | } |
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205 | |||
206 | // Add the current word. |
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207 | WriteWord(CurValue); |
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208 | |||
209 | if (CurBit) |
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210 | CurValue = Val >> (32-CurBit); |
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211 | else |
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212 | CurValue = 0; |
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213 | CurBit = (CurBit+NumBits) & 31; |
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214 | } |
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215 | |||
216 | void FlushToWord() { |
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217 | if (CurBit) { |
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218 | WriteWord(CurValue); |
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219 | CurBit = 0; |
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220 | CurValue = 0; |
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221 | } |
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222 | } |
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223 | |||
224 | void EmitVBR(uint32_t Val, unsigned NumBits) { |
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225 | assert(NumBits <= 32 && "Too many bits to emit!"); |
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226 | uint32_t Threshold = 1U << (NumBits-1); |
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227 | |||
228 | // Emit the bits with VBR encoding, NumBits-1 bits at a time. |
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229 | while (Val >= Threshold) { |
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230 | Emit((Val & ((1 << (NumBits-1))-1)) | (1 << (NumBits-1)), NumBits); |
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231 | Val >>= NumBits-1; |
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232 | } |
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233 | |||
234 | Emit(Val, NumBits); |
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235 | } |
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236 | |||
237 | void EmitVBR64(uint64_t Val, unsigned NumBits) { |
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238 | assert(NumBits <= 32 && "Too many bits to emit!"); |
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239 | if ((uint32_t)Val == Val) |
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240 | return EmitVBR((uint32_t)Val, NumBits); |
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241 | |||
242 | uint32_t Threshold = 1U << (NumBits-1); |
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243 | |||
244 | // Emit the bits with VBR encoding, NumBits-1 bits at a time. |
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245 | while (Val >= Threshold) { |
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246 | Emit(((uint32_t)Val & ((1 << (NumBits - 1)) - 1)) | (1 << (NumBits - 1)), |
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247 | NumBits); |
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248 | Val >>= NumBits-1; |
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249 | } |
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250 | |||
251 | Emit((uint32_t)Val, NumBits); |
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252 | } |
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253 | |||
254 | /// EmitCode - Emit the specified code. |
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255 | void EmitCode(unsigned Val) { |
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256 | Emit(Val, CurCodeSize); |
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257 | } |
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258 | |||
259 | //===--------------------------------------------------------------------===// |
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260 | // Block Manipulation |
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261 | //===--------------------------------------------------------------------===// |
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262 | |||
263 | /// getBlockInfo - If there is block info for the specified ID, return it, |
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264 | /// otherwise return null. |
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265 | BlockInfo *getBlockInfo(unsigned BlockID) { |
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266 | // Common case, the most recent entry matches BlockID. |
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267 | if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID) |
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268 | return &BlockInfoRecords.back(); |
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269 | |||
270 | for (BlockInfo &BI : BlockInfoRecords) |
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271 | if (BI.BlockID == BlockID) |
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272 | return &BI; |
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273 | return nullptr; |
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274 | } |
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275 | |||
276 | void EnterSubblock(unsigned BlockID, unsigned CodeLen) { |
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277 | // Block header: |
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278 | // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen] |
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279 | EmitCode(bitc::ENTER_SUBBLOCK); |
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280 | EmitVBR(BlockID, bitc::BlockIDWidth); |
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281 | EmitVBR(CodeLen, bitc::CodeLenWidth); |
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282 | FlushToWord(); |
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283 | |||
284 | size_t BlockSizeWordIndex = GetWordIndex(); |
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285 | unsigned OldCodeSize = CurCodeSize; |
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286 | |||
287 | // Emit a placeholder, which will be replaced when the block is popped. |
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288 | Emit(0, bitc::BlockSizeWidth); |
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289 | |||
290 | CurCodeSize = CodeLen; |
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291 | |||
292 | // Push the outer block's abbrev set onto the stack, start out with an |
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293 | // empty abbrev set. |
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294 | BlockScope.emplace_back(OldCodeSize, BlockSizeWordIndex); |
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295 | BlockScope.back().PrevAbbrevs.swap(CurAbbrevs); |
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296 | |||
297 | // If there is a blockinfo for this BlockID, add all the predefined abbrevs |
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298 | // to the abbrev list. |
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299 | if (BlockInfo *Info = getBlockInfo(BlockID)) |
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300 | append_range(CurAbbrevs, Info->Abbrevs); |
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301 | } |
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302 | |||
303 | void ExitBlock() { |
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304 | assert(!BlockScope.empty() && "Block scope imbalance!"); |
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305 | const Block &B = BlockScope.back(); |
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306 | |||
307 | // Block tail: |
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308 | // [END_BLOCK, <align4bytes>] |
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309 | EmitCode(bitc::END_BLOCK); |
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310 | FlushToWord(); |
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311 | |||
312 | // Compute the size of the block, in words, not counting the size field. |
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313 | size_t SizeInWords = GetWordIndex() - B.StartSizeWord - 1; |
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314 | uint64_t BitNo = uint64_t(B.StartSizeWord) * 32; |
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315 | |||
316 | // Update the block size field in the header of this sub-block. |
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317 | BackpatchWord(BitNo, SizeInWords); |
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318 | |||
319 | // Restore the inner block's code size and abbrev table. |
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320 | CurCodeSize = B.PrevCodeSize; |
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321 | CurAbbrevs = std::move(B.PrevAbbrevs); |
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322 | BlockScope.pop_back(); |
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323 | FlushToFile(); |
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324 | } |
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325 | |||
326 | //===--------------------------------------------------------------------===// |
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327 | // Record Emission |
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328 | //===--------------------------------------------------------------------===// |
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329 | |||
330 | private: |
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331 | /// EmitAbbreviatedLiteral - Emit a literal value according to its abbrev |
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332 | /// record. This is a no-op, since the abbrev specifies the literal to use. |
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333 | template<typename uintty> |
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334 | void EmitAbbreviatedLiteral(const BitCodeAbbrevOp &Op, uintty V) { |
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335 | assert(Op.isLiteral() && "Not a literal"); |
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336 | // If the abbrev specifies the literal value to use, don't emit |
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337 | // anything. |
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338 | assert(V == Op.getLiteralValue() && |
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339 | "Invalid abbrev for record!"); |
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340 | } |
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341 | |||
342 | /// EmitAbbreviatedField - Emit a single scalar field value with the specified |
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343 | /// encoding. |
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344 | template<typename uintty> |
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345 | void EmitAbbreviatedField(const BitCodeAbbrevOp &Op, uintty V) { |
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346 | assert(!Op.isLiteral() && "Literals should use EmitAbbreviatedLiteral!"); |
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347 | |||
348 | // Encode the value as we are commanded. |
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349 | switch (Op.getEncoding()) { |
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350 | default: llvm_unreachable("Unknown encoding!"); |
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351 | case BitCodeAbbrevOp::Fixed: |
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352 | if (Op.getEncodingData()) |
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353 | Emit((unsigned)V, (unsigned)Op.getEncodingData()); |
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354 | break; |
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355 | case BitCodeAbbrevOp::VBR: |
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356 | if (Op.getEncodingData()) |
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357 | EmitVBR64(V, (unsigned)Op.getEncodingData()); |
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358 | break; |
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359 | case BitCodeAbbrevOp::Char6: |
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360 | Emit(BitCodeAbbrevOp::EncodeChar6((char)V), 6); |
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361 | break; |
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362 | } |
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363 | } |
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364 | |||
365 | /// EmitRecordWithAbbrevImpl - This is the core implementation of the record |
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366 | /// emission code. If BlobData is non-null, then it specifies an array of |
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367 | /// data that should be emitted as part of the Blob or Array operand that is |
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368 | /// known to exist at the end of the record. If Code is specified, then |
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369 | /// it is the record code to emit before the Vals, which must not contain |
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370 | /// the code. |
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371 | template <typename uintty> |
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372 | void EmitRecordWithAbbrevImpl(unsigned Abbrev, ArrayRef<uintty> Vals, |
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373 | StringRef Blob, std::optional<unsigned> Code) { |
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374 | const char *BlobData = Blob.data(); |
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375 | unsigned BlobLen = (unsigned) Blob.size(); |
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376 | unsigned AbbrevNo = Abbrev-bitc::FIRST_APPLICATION_ABBREV; |
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377 | assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!"); |
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378 | const BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo].get(); |
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379 | |||
380 | EmitCode(Abbrev); |
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381 | |||
382 | unsigned i = 0, e = static_cast<unsigned>(Abbv->getNumOperandInfos()); |
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383 | if (Code) { |
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384 | assert(e && "Expected non-empty abbreviation"); |
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385 | const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i++); |
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386 | |||
387 | if (Op.isLiteral()) |
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388 | EmitAbbreviatedLiteral(Op, *Code); |
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389 | else { |
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390 | assert(Op.getEncoding() != BitCodeAbbrevOp::Array && |
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391 | Op.getEncoding() != BitCodeAbbrevOp::Blob && |
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392 | "Expected literal or scalar"); |
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393 | EmitAbbreviatedField(Op, *Code); |
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394 | } |
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395 | } |
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396 | |||
397 | unsigned RecordIdx = 0; |
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398 | for (; i != e; ++i) { |
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399 | const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i); |
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400 | if (Op.isLiteral()) { |
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401 | assert(RecordIdx < Vals.size() && "Invalid abbrev/record"); |
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402 | EmitAbbreviatedLiteral(Op, Vals[RecordIdx]); |
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403 | ++RecordIdx; |
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404 | } else if (Op.getEncoding() == BitCodeAbbrevOp::Array) { |
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405 | // Array case. |
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406 | assert(i + 2 == e && "array op not second to last?"); |
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407 | const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i); |
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408 | |||
409 | // If this record has blob data, emit it, otherwise we must have record |
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410 | // entries to encode this way. |
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411 | if (BlobData) { |
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412 | assert(RecordIdx == Vals.size() && |
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413 | "Blob data and record entries specified for array!"); |
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414 | // Emit a vbr6 to indicate the number of elements present. |
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415 | EmitVBR(static_cast<uint32_t>(BlobLen), 6); |
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416 | |||
417 | // Emit each field. |
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418 | for (unsigned i = 0; i != BlobLen; ++i) |
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419 | EmitAbbreviatedField(EltEnc, (unsigned char)BlobData[i]); |
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420 | |||
421 | // Know that blob data is consumed for assertion below. |
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422 | BlobData = nullptr; |
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423 | } else { |
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424 | // Emit a vbr6 to indicate the number of elements present. |
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425 | EmitVBR(static_cast<uint32_t>(Vals.size()-RecordIdx), 6); |
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426 | |||
427 | // Emit each field. |
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428 | for (unsigned e = Vals.size(); RecordIdx != e; ++RecordIdx) |
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429 | EmitAbbreviatedField(EltEnc, Vals[RecordIdx]); |
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430 | } |
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431 | } else if (Op.getEncoding() == BitCodeAbbrevOp::Blob) { |
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432 | // If this record has blob data, emit it, otherwise we must have record |
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433 | // entries to encode this way. |
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434 | |||
435 | if (BlobData) { |
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436 | assert(RecordIdx == Vals.size() && |
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437 | "Blob data and record entries specified for blob operand!"); |
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438 | |||
439 | assert(Blob.data() == BlobData && "BlobData got moved"); |
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440 | assert(Blob.size() == BlobLen && "BlobLen got changed"); |
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441 | emitBlob(Blob); |
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442 | BlobData = nullptr; |
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443 | } else { |
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444 | emitBlob(Vals.slice(RecordIdx)); |
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445 | } |
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446 | } else { // Single scalar field. |
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447 | assert(RecordIdx < Vals.size() && "Invalid abbrev/record"); |
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448 | EmitAbbreviatedField(Op, Vals[RecordIdx]); |
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449 | ++RecordIdx; |
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450 | } |
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451 | } |
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452 | assert(RecordIdx == Vals.size() && "Not all record operands emitted!"); |
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453 | assert(BlobData == nullptr && |
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454 | "Blob data specified for record that doesn't use it!"); |
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455 | } |
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456 | |||
457 | public: |
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458 | /// Emit a blob, including flushing before and tail-padding. |
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459 | template <class UIntTy> |
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460 | void emitBlob(ArrayRef<UIntTy> Bytes, bool ShouldEmitSize = true) { |
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461 | // Emit a vbr6 to indicate the number of elements present. |
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462 | if (ShouldEmitSize) |
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463 | EmitVBR(static_cast<uint32_t>(Bytes.size()), 6); |
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464 | |||
465 | // Flush to a 32-bit alignment boundary. |
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466 | FlushToWord(); |
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467 | |||
468 | // Emit literal bytes. |
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469 | assert(llvm::all_of(Bytes, [](UIntTy B) { return isUInt<8>(B); })); |
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470 | Out.append(Bytes.begin(), Bytes.end()); |
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471 | |||
472 | // Align end to 32-bits. |
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473 | while (GetBufferOffset() & 3) |
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474 | Out.push_back(0); |
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475 | } |
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476 | void emitBlob(StringRef Bytes, bool ShouldEmitSize = true) { |
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477 | emitBlob(ArrayRef((const uint8_t *)Bytes.data(), Bytes.size()), |
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478 | ShouldEmitSize); |
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479 | } |
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480 | |||
481 | /// EmitRecord - Emit the specified record to the stream, using an abbrev if |
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482 | /// we have one to compress the output. |
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483 | template <typename Container> |
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484 | void EmitRecord(unsigned Code, const Container &Vals, unsigned Abbrev = 0) { |
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485 | if (!Abbrev) { |
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486 | // If we don't have an abbrev to use, emit this in its fully unabbreviated |
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487 | // form. |
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488 | auto Count = static_cast<uint32_t>(std::size(Vals)); |
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489 | EmitCode(bitc::UNABBREV_RECORD); |
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490 | EmitVBR(Code, 6); |
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491 | EmitVBR(Count, 6); |
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492 | for (unsigned i = 0, e = Count; i != e; ++i) |
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493 | EmitVBR64(Vals[i], 6); |
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494 | return; |
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495 | } |
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496 | |||
497 | EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), StringRef(), Code); |
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498 | } |
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499 | |||
500 | /// EmitRecordWithAbbrev - Emit a record with the specified abbreviation. |
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501 | /// Unlike EmitRecord, the code for the record should be included in Vals as |
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502 | /// the first entry. |
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503 | template <typename Container> |
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504 | void EmitRecordWithAbbrev(unsigned Abbrev, const Container &Vals) { |
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505 | EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), StringRef(), std::nullopt); |
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506 | } |
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507 | |||
508 | /// EmitRecordWithBlob - Emit the specified record to the stream, using an |
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509 | /// abbrev that includes a blob at the end. The blob data to emit is |
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510 | /// specified by the pointer and length specified at the end. In contrast to |
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511 | /// EmitRecord, this routine expects that the first entry in Vals is the code |
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512 | /// of the record. |
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513 | template <typename Container> |
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514 | void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals, |
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515 | StringRef Blob) { |
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516 | EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), Blob, std::nullopt); |
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517 | } |
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518 | template <typename Container> |
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519 | void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals, |
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520 | const char *BlobData, unsigned BlobLen) { |
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521 | return EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), |
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522 | StringRef(BlobData, BlobLen), std::nullopt); |
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523 | } |
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524 | |||
525 | /// EmitRecordWithArray - Just like EmitRecordWithBlob, works with records |
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526 | /// that end with an array. |
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527 | template <typename Container> |
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528 | void EmitRecordWithArray(unsigned Abbrev, const Container &Vals, |
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529 | StringRef Array) { |
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530 | EmitRecordWithAbbrevImpl(Abbrev, ArrayRef(Vals), Array, std::nullopt); |
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531 | } |
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532 | template <typename Container> |
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533 | void EmitRecordWithArray(unsigned Abbrev, const Container &Vals, |
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534 | const char *ArrayData, unsigned ArrayLen) { |
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535 | return EmitRecordWithAbbrevImpl( |
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536 | Abbrev, ArrayRef(Vals), StringRef(ArrayData, ArrayLen), std::nullopt); |
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537 | } |
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538 | |||
539 | //===--------------------------------------------------------------------===// |
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540 | // Abbrev Emission |
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541 | //===--------------------------------------------------------------------===// |
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542 | |||
543 | private: |
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544 | // Emit the abbreviation as a DEFINE_ABBREV record. |
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545 | void EncodeAbbrev(const BitCodeAbbrev &Abbv) { |
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546 | EmitCode(bitc::DEFINE_ABBREV); |
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547 | EmitVBR(Abbv.getNumOperandInfos(), 5); |
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548 | for (unsigned i = 0, e = static_cast<unsigned>(Abbv.getNumOperandInfos()); |
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549 | i != e; ++i) { |
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550 | const BitCodeAbbrevOp &Op = Abbv.getOperandInfo(i); |
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551 | Emit(Op.isLiteral(), 1); |
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552 | if (Op.isLiteral()) { |
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553 | EmitVBR64(Op.getLiteralValue(), 8); |
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554 | } else { |
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555 | Emit(Op.getEncoding(), 3); |
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556 | if (Op.hasEncodingData()) |
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557 | EmitVBR64(Op.getEncodingData(), 5); |
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558 | } |
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559 | } |
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560 | } |
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561 | public: |
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562 | |||
563 | /// Emits the abbreviation \p Abbv to the stream. |
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564 | unsigned EmitAbbrev(std::shared_ptr<BitCodeAbbrev> Abbv) { |
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565 | EncodeAbbrev(*Abbv); |
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566 | CurAbbrevs.push_back(std::move(Abbv)); |
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567 | return static_cast<unsigned>(CurAbbrevs.size())-1 + |
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568 | bitc::FIRST_APPLICATION_ABBREV; |
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569 | } |
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570 | |||
571 | //===--------------------------------------------------------------------===// |
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572 | // BlockInfo Block Emission |
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573 | //===--------------------------------------------------------------------===// |
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574 | |||
575 | /// EnterBlockInfoBlock - Start emitting the BLOCKINFO_BLOCK. |
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576 | void EnterBlockInfoBlock() { |
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577 | EnterSubblock(bitc::BLOCKINFO_BLOCK_ID, 2); |
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578 | BlockInfoCurBID = ~0U; |
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579 | BlockInfoRecords.clear(); |
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580 | } |
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581 | private: |
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582 | /// SwitchToBlockID - If we aren't already talking about the specified block |
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583 | /// ID, emit a BLOCKINFO_CODE_SETBID record. |
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584 | void SwitchToBlockID(unsigned BlockID) { |
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585 | if (BlockInfoCurBID == BlockID) return; |
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586 | SmallVector<unsigned, 2> V; |
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587 | V.push_back(BlockID); |
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588 | EmitRecord(bitc::BLOCKINFO_CODE_SETBID, V); |
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589 | BlockInfoCurBID = BlockID; |
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590 | } |
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591 | |||
592 | BlockInfo &getOrCreateBlockInfo(unsigned BlockID) { |
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593 | if (BlockInfo *BI = getBlockInfo(BlockID)) |
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594 | return *BI; |
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595 | |||
596 | // Otherwise, add a new record. |
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597 | BlockInfoRecords.emplace_back(); |
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598 | BlockInfoRecords.back().BlockID = BlockID; |
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599 | return BlockInfoRecords.back(); |
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600 | } |
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601 | |||
602 | public: |
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603 | |||
604 | /// EmitBlockInfoAbbrev - Emit a DEFINE_ABBREV record for the specified |
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605 | /// BlockID. |
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606 | unsigned EmitBlockInfoAbbrev(unsigned BlockID, std::shared_ptr<BitCodeAbbrev> Abbv) { |
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607 | SwitchToBlockID(BlockID); |
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608 | EncodeAbbrev(*Abbv); |
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609 | |||
610 | // Add the abbrev to the specified block record. |
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611 | BlockInfo &Info = getOrCreateBlockInfo(BlockID); |
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612 | Info.Abbrevs.push_back(std::move(Abbv)); |
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613 | |||
614 | return Info.Abbrevs.size()-1+bitc::FIRST_APPLICATION_ABBREV; |
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615 | } |
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616 | }; |
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617 | |||
618 | |||
619 | } // End llvm namespace |
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620 | |||
621 | #endif |