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-rw-r--r--contrib/llvm/lib/Bitcode/Reader/BitstreamReader.cpp390
1 files changed, 390 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Bitcode/Reader/BitstreamReader.cpp b/contrib/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
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index 000000000000..771cf3d927bc
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+++ b/contrib/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
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+//===- BitstreamReader.cpp - BitstreamReader implementation ---------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/ADT/StringRef.h"
+#include <cassert>
+#include <string>
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// BitstreamCursor implementation
+//===----------------------------------------------------------------------===//
+
+/// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
+/// the block, and return true if the block has an error.
+bool BitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
+ // Save the current block's state on BlockScope.
+ BlockScope.push_back(Block(CurCodeSize));
+ BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+
+ // Add the abbrevs specific to this block to the CurAbbrevs list.
+ if (BlockInfo) {
+ if (const BitstreamBlockInfo::BlockInfo *Info =
+ BlockInfo->getBlockInfo(BlockID)) {
+ CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
+ Info->Abbrevs.end());
+ }
+ }
+
+ // Get the codesize of this block.
+ CurCodeSize = ReadVBR(bitc::CodeLenWidth);
+ // We can't read more than MaxChunkSize at a time
+ if (CurCodeSize > MaxChunkSize)
+ return true;
+
+ SkipToFourByteBoundary();
+ unsigned NumWords = Read(bitc::BlockSizeWidth);
+ if (NumWordsP) *NumWordsP = NumWords;
+
+ // Validate that this block is sane.
+ return CurCodeSize == 0 || AtEndOfStream();
+}
+
+static uint64_t readAbbreviatedField(BitstreamCursor &Cursor,
+ const BitCodeAbbrevOp &Op) {
+ assert(!Op.isLiteral() && "Not to be used with literals!");
+
+ // Decode the value as we are commanded.
+ switch (Op.getEncoding()) {
+ case BitCodeAbbrevOp::Array:
+ case BitCodeAbbrevOp::Blob:
+ llvm_unreachable("Should not reach here");
+ case BitCodeAbbrevOp::Fixed:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
+ return Cursor.Read((unsigned)Op.getEncodingData());
+ case BitCodeAbbrevOp::VBR:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
+ return Cursor.ReadVBR64((unsigned)Op.getEncodingData());
+ case BitCodeAbbrevOp::Char6:
+ return BitCodeAbbrevOp::DecodeChar6(Cursor.Read(6));
+ }
+ llvm_unreachable("invalid abbreviation encoding");
+}
+
+static void skipAbbreviatedField(BitstreamCursor &Cursor,
+ const BitCodeAbbrevOp &Op) {
+ assert(!Op.isLiteral() && "Not to be used with literals!");
+
+ // Decode the value as we are commanded.
+ switch (Op.getEncoding()) {
+ case BitCodeAbbrevOp::Array:
+ case BitCodeAbbrevOp::Blob:
+ llvm_unreachable("Should not reach here");
+ case BitCodeAbbrevOp::Fixed:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
+ Cursor.Read((unsigned)Op.getEncodingData());
+ break;
+ case BitCodeAbbrevOp::VBR:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
+ Cursor.ReadVBR64((unsigned)Op.getEncodingData());
+ break;
+ case BitCodeAbbrevOp::Char6:
+ Cursor.Read(6);
+ break;
+ }
+}
+
+/// skipRecord - Read the current record and discard it.
+unsigned BitstreamCursor::skipRecord(unsigned AbbrevID) {
+ // Skip unabbreviated records by reading past their entries.
+ if (AbbrevID == bitc::UNABBREV_RECORD) {
+ unsigned Code = ReadVBR(6);
+ unsigned NumElts = ReadVBR(6);
+ for (unsigned i = 0; i != NumElts; ++i)
+ (void)ReadVBR64(6);
+ return Code;
+ }
+
+ const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
+ const BitCodeAbbrevOp &CodeOp = Abbv->getOperandInfo(0);
+ unsigned Code;
+ if (CodeOp.isLiteral())
+ Code = CodeOp.getLiteralValue();
+ else {
+ if (CodeOp.getEncoding() == BitCodeAbbrevOp::Array ||
+ CodeOp.getEncoding() == BitCodeAbbrevOp::Blob)
+ report_fatal_error("Abbreviation starts with an Array or a Blob");
+ Code = readAbbreviatedField(*this, CodeOp);
+ }
+
+ for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i < e; ++i) {
+ const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+ if (Op.isLiteral())
+ continue;
+
+ if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
+ Op.getEncoding() != BitCodeAbbrevOp::Blob) {
+ skipAbbreviatedField(*this, Op);
+ continue;
+ }
+
+ if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+ // Array case. Read the number of elements as a vbr6.
+ unsigned NumElts = ReadVBR(6);
+
+ // Get the element encoding.
+ assert(i+2 == e && "array op not second to last?");
+ const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
+
+ // Read all the elements.
+ // Decode the value as we are commanded.
+ switch (EltEnc.getEncoding()) {
+ default:
+ report_fatal_error("Array element type can't be an Array or a Blob");
+ case BitCodeAbbrevOp::Fixed:
+ assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
+ JumpToBit(GetCurrentBitNo() + NumElts * EltEnc.getEncodingData());
+ break;
+ case BitCodeAbbrevOp::VBR:
+ assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
+ for (; NumElts; --NumElts)
+ ReadVBR64((unsigned)EltEnc.getEncodingData());
+ break;
+ case BitCodeAbbrevOp::Char6:
+ JumpToBit(GetCurrentBitNo() + NumElts * 6);
+ break;
+ }
+ continue;
+ }
+
+ assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
+ // Blob case. Read the number of bytes as a vbr6.
+ unsigned NumElts = ReadVBR(6);
+ SkipToFourByteBoundary(); // 32-bit alignment
+
+ // Figure out where the end of this blob will be including tail padding.
+ size_t NewEnd = GetCurrentBitNo()+((NumElts+3)&~3)*8;
+
+ // If this would read off the end of the bitcode file, just set the
+ // record to empty and return.
+ if (!canSkipToPos(NewEnd/8)) {
+ skipToEnd();
+ break;
+ }
+
+ // Skip over the blob.
+ JumpToBit(NewEnd);
+ }
+ return Code;
+}
+
+unsigned BitstreamCursor::readRecord(unsigned AbbrevID,
+ SmallVectorImpl<uint64_t> &Vals,
+ StringRef *Blob) {
+ if (AbbrevID == bitc::UNABBREV_RECORD) {
+ unsigned Code = ReadVBR(6);
+ unsigned NumElts = ReadVBR(6);
+ for (unsigned i = 0; i != NumElts; ++i)
+ Vals.push_back(ReadVBR64(6));
+ return Code;
+ }
+
+ const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
+
+ // Read the record code first.
+ assert(Abbv->getNumOperandInfos() != 0 && "no record code in abbreviation?");
+ const BitCodeAbbrevOp &CodeOp = Abbv->getOperandInfo(0);
+ unsigned Code;
+ if (CodeOp.isLiteral())
+ Code = CodeOp.getLiteralValue();
+ else {
+ if (CodeOp.getEncoding() == BitCodeAbbrevOp::Array ||
+ CodeOp.getEncoding() == BitCodeAbbrevOp::Blob)
+ report_fatal_error("Abbreviation starts with an Array or a Blob");
+ Code = readAbbreviatedField(*this, CodeOp);
+ }
+
+ for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i != e; ++i) {
+ const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+ if (Op.isLiteral()) {
+ Vals.push_back(Op.getLiteralValue());
+ continue;
+ }
+
+ if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
+ Op.getEncoding() != BitCodeAbbrevOp::Blob) {
+ Vals.push_back(readAbbreviatedField(*this, Op));
+ continue;
+ }
+
+ if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+ // Array case. Read the number of elements as a vbr6.
+ unsigned NumElts = ReadVBR(6);
+
+ // Get the element encoding.
+ if (i + 2 != e)
+ report_fatal_error("Array op not second to last");
+ const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
+ if (!EltEnc.isEncoding())
+ report_fatal_error(
+ "Array element type has to be an encoding of a type");
+
+ // Read all the elements.
+ switch (EltEnc.getEncoding()) {
+ default:
+ report_fatal_error("Array element type can't be an Array or a Blob");
+ case BitCodeAbbrevOp::Fixed:
+ for (; NumElts; --NumElts)
+ Vals.push_back(Read((unsigned)EltEnc.getEncodingData()));
+ break;
+ case BitCodeAbbrevOp::VBR:
+ for (; NumElts; --NumElts)
+ Vals.push_back(ReadVBR64((unsigned)EltEnc.getEncodingData()));
+ break;
+ case BitCodeAbbrevOp::Char6:
+ for (; NumElts; --NumElts)
+ Vals.push_back(BitCodeAbbrevOp::DecodeChar6(Read(6)));
+ }
+ continue;
+ }
+
+ assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
+ // Blob case. Read the number of bytes as a vbr6.
+ unsigned NumElts = ReadVBR(6);
+ SkipToFourByteBoundary(); // 32-bit alignment
+
+ // Figure out where the end of this blob will be including tail padding.
+ size_t CurBitPos = GetCurrentBitNo();
+ size_t NewEnd = CurBitPos+((NumElts+3)&~3)*8;
+
+ // If this would read off the end of the bitcode file, just set the
+ // record to empty and return.
+ if (!canSkipToPos(NewEnd/8)) {
+ Vals.append(NumElts, 0);
+ skipToEnd();
+ break;
+ }
+
+ // Otherwise, inform the streamer that we need these bytes in memory. Skip
+ // over tail padding first, in case jumping to NewEnd invalidates the Blob
+ // pointer.
+ JumpToBit(NewEnd);
+ const char *Ptr = (const char *)getPointerToBit(CurBitPos, NumElts);
+
+ // If we can return a reference to the data, do so to avoid copying it.
+ if (Blob) {
+ *Blob = StringRef(Ptr, NumElts);
+ } else {
+ // Otherwise, unpack into Vals with zero extension.
+ for (; NumElts; --NumElts)
+ Vals.push_back((unsigned char)*Ptr++);
+ }
+ }
+
+ return Code;
+}
+
+void BitstreamCursor::ReadAbbrevRecord() {
+ auto Abbv = std::make_shared<BitCodeAbbrev>();
+ unsigned NumOpInfo = ReadVBR(5);
+ for (unsigned i = 0; i != NumOpInfo; ++i) {
+ bool IsLiteral = Read(1);
+ if (IsLiteral) {
+ Abbv->Add(BitCodeAbbrevOp(ReadVBR64(8)));
+ continue;
+ }
+
+ BitCodeAbbrevOp::Encoding E = (BitCodeAbbrevOp::Encoding)Read(3);
+ if (BitCodeAbbrevOp::hasEncodingData(E)) {
+ uint64_t Data = ReadVBR64(5);
+
+ // 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 == BitCodeAbbrevOp::Fixed || E == BitCodeAbbrevOp::VBR) &&
+ Data == 0) {
+ Abbv->Add(BitCodeAbbrevOp(0));
+ continue;
+ }
+
+ if ((E == BitCodeAbbrevOp::Fixed || E == BitCodeAbbrevOp::VBR) &&
+ Data > MaxChunkSize)
+ report_fatal_error(
+ "Fixed or VBR abbrev record with size > MaxChunkData");
+
+ Abbv->Add(BitCodeAbbrevOp(E, Data));
+ } else
+ Abbv->Add(BitCodeAbbrevOp(E));
+ }
+
+ if (Abbv->getNumOperandInfos() == 0)
+ report_fatal_error("Abbrev record with no operands");
+ CurAbbrevs.push_back(std::move(Abbv));
+}
+
+Optional<BitstreamBlockInfo>
+BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
+ if (EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID)) return None;
+
+ BitstreamBlockInfo NewBlockInfo;
+
+ SmallVector<uint64_t, 64> Record;
+ BitstreamBlockInfo::BlockInfo *CurBlockInfo = nullptr;
+
+ // Read all the records for this module.
+ while (true) {
+ BitstreamEntry Entry = advanceSkippingSubblocks(AF_DontAutoprocessAbbrevs);
+
+ switch (Entry.Kind) {
+ case llvm::BitstreamEntry::SubBlock: // Handled for us already.
+ case llvm::BitstreamEntry::Error:
+ return None;
+ case llvm::BitstreamEntry::EndBlock:
+ return std::move(NewBlockInfo);
+ case llvm::BitstreamEntry::Record:
+ // The interesting case.
+ break;
+ }
+
+ // Read abbrev records, associate them with CurBID.
+ if (Entry.ID == bitc::DEFINE_ABBREV) {
+ if (!CurBlockInfo) return None;
+ ReadAbbrevRecord();
+
+ // ReadAbbrevRecord installs the abbrev in CurAbbrevs. Move it to the
+ // appropriate BlockInfo.
+ CurBlockInfo->Abbrevs.push_back(std::move(CurAbbrevs.back()));
+ CurAbbrevs.pop_back();
+ continue;
+ }
+
+ // Read a record.
+ Record.clear();
+ switch (readRecord(Entry.ID, Record)) {
+ default: break; // Default behavior, ignore unknown content.
+ case bitc::BLOCKINFO_CODE_SETBID:
+ if (Record.size() < 1) return None;
+ CurBlockInfo = &NewBlockInfo.getOrCreateBlockInfo((unsigned)Record[0]);
+ break;
+ case bitc::BLOCKINFO_CODE_BLOCKNAME: {
+ if (!CurBlockInfo) return None;
+ if (!ReadBlockInfoNames)
+ break; // Ignore name.
+ std::string Name;
+ for (unsigned i = 0, e = Record.size(); i != e; ++i)
+ Name += (char)Record[i];
+ CurBlockInfo->Name = Name;
+ break;
+ }
+ case bitc::BLOCKINFO_CODE_SETRECORDNAME: {
+ if (!CurBlockInfo) return None;
+ if (!ReadBlockInfoNames)
+ break; // Ignore name.
+ std::string Name;
+ for (unsigned i = 1, e = Record.size(); i != e; ++i)
+ Name += (char)Record[i];
+ CurBlockInfo->RecordNames.push_back(std::make_pair((unsigned)Record[0],
+ Name));
+ break;
+ }
+ }
+ }
+}