Subzero: Add necessary PNaCl files for standalone build.

pnacl-llvm/NaClBitstreamReader.cpp

+//===- NaClBitstreamReader.cpp --------------------------------------------===//
+//     NaClBitstreamReader implementation
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Bitcode/NaCl/NaClBitstreamReader.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+
+static const char *ErrorLevelName[] = {
+  "Warning",
+  "Error",
+  "Fatal"
+};
+
+} // End of anonymous namespace.
+
+std::string llvm::naclbitc::getBitAddress(uint64_t Bit) {
+  std::string Buffer;
+  raw_string_ostream Stream(Buffer);
+  Stream << (Bit / 8) << ":" << (Bit % 8);
+  return Stream.str();
+}
+
+raw_ostream &llvm::naclbitc::ErrorAt(
+    raw_ostream &Out, ErrorLevel Level, uint64_t BitPosition) {
+  assert(Level < array_lengthof(::ErrorLevelName));
+  return Out << ErrorLevelName[Level] << "("
+             << naclbitc::getBitAddress(BitPosition) << "): ";
+}
+
+//===----------------------------------------------------------------------===//
+//  NaClBitstreamCursor implementation
+//===----------------------------------------------------------------------===//
+
+void NaClBitstreamCursor::ErrorHandler::
+Fatal(const std::string &ErrorMessage) const {
+  // Default implementation is simply print message, and the bit where
+  // the error occurred.
+  std::string Buffer;
+  raw_string_ostream StrBuf(Buffer);
+  naclbitc::ErrorAt(StrBuf, naclbitc::Fatal,
+                    Cursor.getErrorBitNo(getCurrentBitNo())) << ErrorMessage;
+  report_fatal_error(StrBuf.str());
+}
+
+void NaClBitstreamCursor::reportInvalidAbbrevNumber(unsigned AbbrevNo) const {
+  std::string Buffer;
+  raw_string_ostream StrBuf(Buffer);
+  StrBuf << "Invalid abbreviation # " << AbbrevNo << " defined for record";
+  ErrHandler->Fatal(StrBuf.str());
+}
+
+void NaClBitstreamCursor::reportInvalidJumpToBit(uint64_t BitNo) const {
+  std::string Buffer;
+  raw_string_ostream StrBuf(Buffer);
+  StrBuf << "Invalid jump to bit " << BitNo;
+  ErrHandler->Fatal(StrBuf.str());
+}
+
+/// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
+/// the block, and return true if the block has an error.
+bool NaClBitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
+  const bool IsFixed = true;
+  NaClBitcodeSelectorAbbrev
+      CodeAbbrev(IsFixed, ReadVBR(naclbitc::CodeLenWidth));
+  BlockScope.push_back(Block(BitStream->getBlockInfo(BlockID), CodeAbbrev));
+  SkipToFourByteBoundary();
+  unsigned NumWords = Read(naclbitc::BlockSizeWidth);
+  if (NumWordsP) *NumWordsP = NumWords;
+
+  // Validate that this block is sane.
+  if (BlockScope.back().getCodeAbbrev().NumBits == 0 || AtEndOfStream())
+    return true;
+
+  return false;
+}
+
+void NaClBitstreamCursor::skipAbbreviatedField(const NaClBitCodeAbbrevOp &Op) {
+  // Decode the value as we are commanded.
+  switch (Op.getEncoding()) {
+  case NaClBitCodeAbbrevOp::Literal:
+    // No read necessary for literal.
+    break;
+  case NaClBitCodeAbbrevOp::Fixed:
+    (void)Read((unsigned)Op.getValue());
+    break;
+  case NaClBitCodeAbbrevOp::VBR:
+    (void)ReadVBR64((unsigned)Op.getValue());
+    break;
+  case NaClBitCodeAbbrevOp::Array:
+    // This can't happen because the abbreviation must be valid.
+    llvm_unreachable("Bad array abbreviation encoding!");
+    break;
+  case NaClBitCodeAbbrevOp::Char6:
+    (void)Read(6);
+    break;
+  }
+}
+
+/// skipRecord - Read the current record and discard it.
+void NaClBitstreamCursor::skipRecord(unsigned AbbrevID) {
+  // Skip unabbreviated records by reading past their entries.
+  if (AbbrevID == naclbitc::UNABBREV_RECORD) {
+    unsigned Code = ReadVBR(6);
+    (void)Code;
+    unsigned NumElts = ReadVBR(6);
+    for (unsigned i = 0; i != NumElts; ++i)
+      (void)ReadVBR64(6);
+    SkipToByteBoundaryIfAligned();
+    return;
+  }
+
+  const NaClBitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
+
+  for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
+    const NaClBitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+    switch (Op.getEncoding()) {
+    default:
+      skipAbbreviatedField(Op);
+      break;
+    case NaClBitCodeAbbrevOp::Literal:
+      break;
+    case NaClBitCodeAbbrevOp::Array: {
+      // Array case.  Read the number of elements as a vbr6.
+      unsigned NumElts = ReadVBR(6);
+
+      // Get the element encoding.
+      const NaClBitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
+
+      // Read all the elements.
+      for (; NumElts; --NumElts)
+        skipAbbreviatedField(EltEnc);
+      break;
+    }
+    }
+  }
+  SkipToByteBoundaryIfAligned();
+}
+
+bool NaClBitstreamCursor::readRecordAbbrevField(
+    const NaClBitCodeAbbrevOp &Op, uint64_t &Value) {
+  switch (Op.getEncoding()) {
+  case NaClBitCodeAbbrevOp::Literal:
+    Value = Op.getValue();
+    break;
+  case NaClBitCodeAbbrevOp::Array:
+    // Returns number of elements in the array.
+    Value = ReadVBR(6);
+    return true;
+  case NaClBitCodeAbbrevOp::Fixed:
+    Value = Read((unsigned)Op.getValue());
+    break;
+  case NaClBitCodeAbbrevOp::VBR:
+    Value = ReadVBR64((unsigned)Op.getValue());
+    break;
+  case NaClBitCodeAbbrevOp::Char6:
+    Value = NaClBitCodeAbbrevOp::DecodeChar6(Read(6));
+    break;
+  }
+  return false;
+}
+
+uint64_t NaClBitstreamCursor::readArrayAbbreviatedField(
+    const NaClBitCodeAbbrevOp &Op) {
+  // Decode the value as we are commanded.
+  switch (Op.getEncoding()) {
+  case NaClBitCodeAbbrevOp::Literal:
+    return Op.getValue();
+  case NaClBitCodeAbbrevOp::Fixed:
+    return Read((unsigned)Op.getValue());
+  case NaClBitCodeAbbrevOp::VBR:
+    return ReadVBR64((unsigned)Op.getValue());
+  case NaClBitCodeAbbrevOp::Array:
+    // This can't happen because the abbreviation must be valid.
+    llvm_unreachable("Bad array abbreviation encoding!");
+    break;
+  case NaClBitCodeAbbrevOp::Char6:
+    return NaClBitCodeAbbrevOp::DecodeChar6(Read(6));
+  }
+}
+
+void NaClBitstreamCursor::readArrayAbbrev(
+    const NaClBitCodeAbbrevOp &Op, unsigned NumArrayElements,
+    SmallVectorImpl<uint64_t> &Vals) {
+  for (; NumArrayElements; --NumArrayElements) {
+    Vals.push_back(readArrayAbbreviatedField(Op));
+  }
+}
+
+unsigned NaClBitstreamCursor::readRecord(unsigned AbbrevID,
+                                         SmallVectorImpl<uint64_t> &Vals) {
+  if (AbbrevID == naclbitc::UNABBREV_RECORD) {
+    unsigned Code = ReadVBR(6);
+    unsigned NumElts = ReadVBR(6);
+    for (unsigned i = 0; i != NumElts; ++i)
+      Vals.push_back(ReadVBR64(6));
+    SkipToByteBoundaryIfAligned();
+    return Code;
+  }
+
+  // Read code.
+  const NaClBitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
+  uint64_t Value;
+  unsigned Code;
+  if (readRecordAbbrevField(Abbv->getOperandInfo(0), Value)) {
+    // Array found, use to read all elements.
+    if (Value == 0)
+      ErrHandler->Fatal("No code found for record!");
+    const NaClBitCodeAbbrevOp &Op = Abbv->getOperandInfo(1);
+    Code = readArrayAbbreviatedField(Op);
+    readArrayAbbrev(Op, Value - 1, Vals);
+    SkipToByteBoundaryIfAligned();
+    return Code;
+  }
+  Code = Value;
+
+  // Read arguments.
+  unsigned NumOperands = Abbv->getNumOperandInfos();
+  for (unsigned i = 1; i != NumOperands; ++i) {
+    if (readRecordAbbrevField(Abbv->getOperandInfo(i), Value)) {
+      ++i;
+      readArrayAbbrev(Abbv->getOperandInfo(i), Value, Vals);
+      SkipToByteBoundaryIfAligned();
+      return Code;
+    }
+    Vals.push_back(Value);
+  }
+  SkipToByteBoundaryIfAligned();
+  return Code;
+}
+
+
+NaClBitCodeAbbrevOp::Encoding NaClBitstreamCursor::
+getEncoding(uint64_t Value) {
+  if (!NaClBitCodeAbbrevOp::isValidEncoding(Value)) {
+    std::string Buffer;
+    raw_string_ostream StrBuf(Buffer);
+    StrBuf << "Invalid abbreviation encoding specified in bitcode file: "
+           << Value;
+    ErrHandler->Fatal(StrBuf.str());
+  }
+  return NaClBitCodeAbbrevOp::Encoding(Value);
+}
+
+void NaClBitstreamCursor::ReadAbbrevRecord(bool IsLocal,
+                                           NaClAbbrevListener *Listener) {
+  NaClBitCodeAbbrev *Abbv = BlockScope.back().appendLocalCreate();
+  unsigned NumOpInfo = ReadVBR(5);
+  if (Listener) Listener->Values.push_back(NumOpInfo);
+  for (unsigned i = 0; i != NumOpInfo; ++i) {
+    bool IsLiteral = Read(1) ? true : false;
+    if (Listener) Listener->Values.push_back(IsLiteral);
+    if (IsLiteral) {
+      uint64_t Value = ReadVBR64(8);
+      if (Listener) Listener->Values.push_back(Value);
+      Abbv->Add(NaClBitCodeAbbrevOp(Value));
+      continue;
+    }
+    NaClBitCodeAbbrevOp::Encoding E = getEncoding(Read(3));
+    if (Listener) Listener->Values.push_back(E);
+    if (NaClBitCodeAbbrevOp::hasValue(E)) {
+      unsigned Data = ReadVBR64(5);
+      if (Listener) Listener->Values.push_back(Data);
+
+      // As a special case, handle fixed(0) (i.e., a fixed field with zero bits)
+      // and vbr(0) as a literal zero.  This is decoded the same way, and avoids
+      // a slow path in Read() to have to handle reading zero bits.
+      if ((E == NaClBitCodeAbbrevOp::Fixed || E == NaClBitCodeAbbrevOp::VBR) &&
+          Data == 0) {
+        if (Listener) Listener->Values.push_back(0);
+        Abbv->Add(NaClBitCodeAbbrevOp(0));
+        continue;
+      }
+      if (!NaClBitCodeAbbrevOp::isValid(E, Data)) {
+        std::string Buffer;
+        raw_string_ostream StrBuf(Buffer);
+        StrBuf << "Invalid abbreviation encoding ("
+               << NaClBitCodeAbbrevOp::getEncodingName(E)
+               << ", " << Data << ")";
+        ErrHandler->Fatal(StrBuf.str());
+      }
+      Abbv->Add(NaClBitCodeAbbrevOp(E, Data));
+    } else {
+      if (!NaClBitCodeAbbrevOp::isValid(E)) {
+        std::string Buffer;
+        raw_string_ostream StrBuf(Buffer);
+        StrBuf << "Invalid abbreviation encoding ("
+               << NaClBitCodeAbbrevOp::getEncodingName(E) << ")";
+        ErrHandler->Fatal(StrBuf.str());
+      }
+      Abbv->Add(NaClBitCodeAbbrevOp(E));
+    }
+  }
+  SkipToByteBoundaryIfAligned();
+  if (!Abbv->isValid())
+    ErrHandler->Fatal("Invalid abbreviation specified in bitcode file");
+  if (Listener) {
+    Listener->ProcessAbbreviation(Abbv, IsLocal);
+    // Reset record information of the listener.
+    Listener->Values.clear();
+    Listener->StartBit = GetCurrentBitNo();
+  }
+}
+
+void NaClBitstreamCursor::SkipAbbrevRecord() {
+  unsigned NumOpInfo = ReadVBR(5);
+  for (unsigned i = 0; i != NumOpInfo; ++i) {
+    bool IsLiteral = Read(1) ? true : false;
+    if (IsLiteral) {
+      ReadVBR64(8);
+      continue;
+    }
+    NaClBitCodeAbbrevOp::Encoding E = getEncoding(Read(3));
+    if (NaClBitCodeAbbrevOp::hasValue(E)) {
+      ReadVBR64(5);
+    }
+  }
+  SkipToByteBoundaryIfAligned();
+}
+
+namespace {
+
+unsigned ValidBlockIDs[] = {
+  naclbitc::BLOCKINFO_BLOCK_ID,
+  naclbitc::CONSTANTS_BLOCK_ID,
+  naclbitc::FUNCTION_BLOCK_ID,
+  naclbitc::GLOBALVAR_BLOCK_ID,
+  naclbitc::MODULE_BLOCK_ID,
+  naclbitc::TOP_LEVEL_BLOCKID,
+  naclbitc::TYPE_BLOCK_ID_NEW,
+  naclbitc::VALUE_SYMTAB_BLOCK_ID
+};
+
+} // end of anonymous namespace
+
+NaClBitstreamReader::BlockInfoRecordsMap::
+BlockInfoRecordsMap() : IsFrozen(false) {
+  for (size_t BlockID : ValidBlockIDs) {
+    std::unique_ptr<BlockInfo> Info(new BlockInfo(BlockID));
+    KnownInfos.emplace(BlockID, std::move(Info));
+  }
+}
+
+NaClBitstreamReader::BlockInfo * NaClBitstreamReader::BlockInfoRecordsMap::
+getOrCreateUnknownBlockInfo(unsigned BlockID) {
+  std::unique_lock<std::mutex> Lock(UnknownBlockInfoLock);
+  while (true) {
+    auto Pos = UnknownInfos.find(BlockID);
+    if (Pos != UnknownInfos.end())
+      return Pos->second.get();
+    // Install, then let next iteration find.
+    std::unique_ptr<BlockInfo> Info(new BlockInfo(BlockID));
+    UnknownInfos.emplace(BlockID, std::move(Info));
+  }
+}
+
+NaClBitstreamReader::BlockInfoRecordsMap::UpdateLock::
+UpdateLock(BlockInfoRecordsMap &BlockInfoRecords)
+    : BlockInfoRecords(BlockInfoRecords),
+      Lock(BlockInfoRecords.UpdateRecordsLock) {}
+
+NaClBitstreamReader::BlockInfoRecordsMap::UpdateLock::
+~UpdateLock() {
+  if (BlockInfoRecords.freeze())
+    report_fatal_error("Global abbreviations block frozen while building.");
+}
+
+bool NaClBitstreamCursor::ReadBlockInfoBlock(NaClAbbrevListener *Listener) {
+  // If this is the second read of the block info block, skip it.
+  if (BitStream->BlockInfoRecords->isFrozen())
+    return SkipBlock();
+
+  NaClBitstreamReader::BlockInfoRecordsMap::UpdateLock
+      Lock(*BitStream->BlockInfoRecords);
+  unsigned NumWords;
+  if (EnterSubBlock(naclbitc::BLOCKINFO_BLOCK_ID, &NumWords)) return true;
+
+  if (Listener) Listener->BeginBlockInfoBlock(NumWords);
+
+  NaClBitcodeRecordVector Record;
+  Block &CurBlock = BlockScope.back();
+  NaClBitstreamReader::AbbrevList *UpdateAbbrevs =
+      &CurBlock.GlobalAbbrevs->getAbbrevs();
+  bool FoundSetBID = false;
+
+  // Read records of the BlockInfo block.
+  while (1) {
+    if (Listener) Listener->StartBit = GetCurrentBitNo();
+    NaClBitstreamEntry Entry = advance(AF_DontAutoprocessAbbrevs, Listener);
+
+    switch (Entry.Kind) {
+    case llvm::NaClBitstreamEntry::SubBlock:  // PNaCl doesn't allow!
+    case llvm::NaClBitstreamEntry::Error:
+      return true;
+    case llvm::NaClBitstreamEntry::EndBlock:
+      if (Listener) Listener->EndBlockInfoBlock();
+      return false;
+    case llvm::NaClBitstreamEntry::Record:
+      // The interesting case.
+      break;
+    }
+
+    // Read abbrev records, associate them with CurBID.
+    if (Entry.ID == naclbitc::DEFINE_ABBREV) {
+      ReadAbbrevRecord(false, Listener);
+
+      // ReadAbbrevRecord installs a local abbreviation.  Move it to the
+      // appropriate BlockInfo if the corresponding SetBID record has been
+      // found.
+      if (FoundSetBID)
+        CurBlock.moveLocalAbbrevToAbbrevList(UpdateAbbrevs);
+      continue;
+    }
+
+    // Read a record.
+    Record.clear();
+    switch (readRecord(Entry.ID, Record)) {
+      default: 
+        // No other records should be found!
+        return true;
+      case naclbitc::BLOCKINFO_CODE_SETBID:
+        if (Record.size() < 1) return true;
+        FoundSetBID = true;
+        UpdateAbbrevs =
+            &BitStream->getBlockInfo((unsigned)Record[0])->getAbbrevs();
+        if (Listener) {
+          Listener->Values = Record;
+          Listener->SetBID();
+        }
+        break;
+    }
+  }
+}