[Bitcode] Move Bitstream to a separate library

[thegameg]

Summary

This moves Bitcode/Bitstream*, Bitcode/BitCodes.h to Bitstream/.

This is needed to avoid a circular dependency when using the bitstream code for parsing optimization remarks.

Since Bitcode uses Core for the IR part:

libLLVMRemarks -> Bitcode -> Core

and Core uses libLLVMRemarks to generate remarks (see IR/RemarkStreamer.cpp):

Core -> libLLVMRemarks

we need to separate the Bitstream and Bitcode part.

For clang-doc, it seems that it doesn't need the whole bitcode layer, so I updated the CMake to only use the bitstream part.

[JDevlieghere]

LGTM

cfe/trunk/include/clang/Frontend/SerializedDiagnosticPrinter.h

 //===--- SerializedDiagnosticPrinter.h - Diagnostics serializer -*- 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
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_FRONTEND_SERIALIZEDDIAGNOSTICPRINTER_H
 #define LLVM_CLANG_FRONTEND_SERIALIZEDDIAGNOSTICPRINTER_H
 
 #include "clang/Basic/LLVM.h"
 #include "clang/Frontend/SerializedDiagnostics.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 
 namespace llvm {
 class raw_ostream;
 }
 
 namespace clang {
 class DiagnosticConsumer;
 class DiagnosticsEngine;

cfe/trunk/include/clang/Frontend/SerializedDiagnosticReader.h

 //===- SerializedDiagnosticReader.h - Reads diagnostics ---------*- 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
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_FRONTEND_SERIALIZEDDIAGNOSTICREADER_H
 #define LLVM_CLANG_FRONTEND_SERIALIZEDDIAGNOSTICREADER_H
 
 #include "clang/Basic/LLVM.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/ErrorOr.h"
 #include <system_error>
 
 namespace clang {
 namespace serialized_diags {
 
 enum class SDError {

cfe/trunk/include/clang/Frontend/SerializedDiagnostics.h

 //===--- SerializedDiagnostics.h - Common data for serialized diagnostics -===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_FRONTEND_SERIALIZE_DIAGNOSTICS_H_
 #define LLVM_CLANG_FRONTEND_SERIALIZE_DIAGNOSTICS_H_
 
-#include "llvm/Bitcode/BitCodes.h"
+#include "llvm/Bitstream/BitCodes.h"
 
 namespace clang {
 namespace serialized_diags {
 
 enum BlockIDs {
   /// A top-level block which represents any meta data associated
   /// with the diagostics, including versioning of the format.
   BLOCK_META = llvm::bitc::FIRST_APPLICATION_BLOCKID,

cfe/trunk/include/clang/Serialization/ASTBitCodes.h

 #define LLVM_CLANG_SERIALIZATION_ASTBITCODES_H
 
 #include "clang/AST/DeclarationName.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/OperatorKinds.h"
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/DenseMapInfo.h"
-#include "llvm/Bitcode/BitCodes.h"
+#include "llvm/Bitstream/BitCodes.h"
 #include <cassert>
 #include <cstdint>
 
 namespace clang {
 namespace serialization {
 
     /// AST file major version number supported by this version of
     /// Clang.

cfe/trunk/include/clang/Serialization/ASTReader.h

 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <cstddef>
 #include <cstdint>

cfe/trunk/include/clang/Serialization/ASTWriter.h

 #include "clang/Serialization/PCHContainerOperations.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <ctime>
 #include <memory>
 #include <queue>
 #include <string>
 #include <utility>

cfe/trunk/include/clang/Serialization/Module.h

 #include "clang/Serialization/ASTBitCodes.h"
 #include "clang/Serialization/ContinuousRangeMap.h"
 #include "clang/Serialization/ModuleFileExtension.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Endian.h"
 #include <cassert>
 #include <cstdint>
 #include <memory>
 #include <string>
 #include <vector>
 
 namespace clang {

cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp

 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/CodeGen/BackendUtil.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Path.h"

cfe/trunk/lib/Frontend/ASTUnit.cpp

 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/iterator_range.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"

cfe/trunk/lib/Frontend/CMakeLists.txt

 add_subdirectory(Rewrite)
 
 set(LLVM_LINK_COMPONENTS
   BitReader
+  BitstreamReader
   Option
   ProfileData
   Support
   )
 
 set(optional_deps intrinsics_gen)
 if (CLANG_BUILT_STANDALONE)
   set(optional_deps)

cfe/trunk/lib/Frontend/SerializedDiagnosticReader.cpp

 //===- SerializedDiagnosticReader.cpp - Reads diagnostics -----------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/Frontend/SerializedDiagnosticReader.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Frontend/SerializedDiagnostics.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitCodes.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitCodes.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/ManagedStatic.h"
 #include <cstdint>
 #include <system_error>
 
 using namespace clang;

cfe/trunk/lib/Frontend/TestModuleFileExtension.h

 //===-- TestModuleFileExtension.h - Module Extension Tester -----*- 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
 //
 //===----------------------------------------------------------------------===//
 #ifndef LLVM_CLANG_FRONTEND_TESTMODULEFILEEXTENSION_H
 #define LLVM_CLANG_FRONTEND_TESTMODULEFILEEXTENSION_H
 
 #include "clang/Serialization/ModuleFileExtension.h"
 #include "clang/Basic/LLVM.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include <string>
 
 namespace clang {
 
 /// A module file extension used for testing purposes.
 class TestModuleFileExtension : public ModuleFileExtension {
   std::string BlockName;
   unsigned MajorVersion;

cfe/trunk/lib/Frontend/TestModuleFileExtension.cpp

 //===-- TestModuleFileExtension.cpp - Module Extension Tester -------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 #include "TestModuleFileExtension.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/Hashing.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdio>
 using namespace clang;
 using namespace clang::serialization;
 
 TestModuleFileExtension::Writer::~Writer() { }
 
 void TestModuleFileExtension::Writer::writeExtensionContents(

cfe/trunk/lib/Serialization/ASTReader.cpp

 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/iterator_range.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"

cfe/trunk/lib/Serialization/ASTReaderDecl.cpp

 #include "clang/Serialization/ContinuousRangeMap.h"
 #include "clang/Serialization/Module.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/iterator_range.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/SaveAndRestore.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
 #include <cstring>
 #include <string>

cfe/trunk/lib/Serialization/ASTReaderStmt.cpp

 #include "clang/Basic/Specifiers.h"
 #include "clang/Basic/TypeTraits.h"
 #include "clang/Lex/Token.h"
 #include "clang/Serialization/ASTBitCodes.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
 #include <string>
 
 using namespace clang;

cfe/trunk/lib/Serialization/ASTWriter.cpp

 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitCodes.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitCodes.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/EndianStream.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"

cfe/trunk/lib/Serialization/ASTWriterDecl.cpp

 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/DeclVisitor.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/OpenMPClause.h"
 #include "clang/AST/PrettyDeclStackTrace.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/ASTWriter.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Support/ErrorHandling.h"
 using namespace clang;
 using namespace serialization;
 
 //===----------------------------------------------------------------------===//
 // Declaration serialization
 //===----------------------------------------------------------------------===//
 

cfe/trunk/lib/Serialization/ASTWriterStmt.cpp

 
 #include "clang/Serialization/ASTWriter.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/StmtVisitor.h"
 #include "clang/Lex/Token.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
 // Statement/expression serialization
 //===----------------------------------------------------------------------===//
 
 namespace clang {
 

cfe/trunk/lib/Serialization/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   BitReader
+  BitstreamReader
   Support
   )
 
 
 add_clang_library(clangSerialization
   ASTCommon.cpp
   ASTReader.cpp
   ASTReaderDecl.cpp

cfe/trunk/lib/Serialization/GeneratePCH.cpp

 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/AST/ASTContext.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/SemaConsumer.h"
 #include "clang/Serialization/ASTWriter.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 
 using namespace clang;
 
 PCHGenerator::PCHGenerator(
     const Preprocessor &PP, InMemoryModuleCache &ModuleCache,
     StringRef OutputFile, StringRef isysroot, std::shared_ptr<PCHBuffer> Buffer,
     ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
     bool AllowASTWithErrors, bool IncludeTimestamps,

cfe/trunk/lib/Serialization/GlobalModuleIndex.cpp

 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Serialization/ASTBitCodes.h"
 #include "clang/Serialization/GlobalModuleIndex.h"
 #include "clang/Serialization/Module.h"
 #include "clang/Serialization/PCHContainerOperations.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SmallString.h"
-#include "llvm/Bitcode/BitstreamReader.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LockFileManager.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/OnDiskHashTable.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TimeProfiler.h"
 #include <cstdio>

cfe/trunk/lib/Serialization/PCHContainerOperations.cpp

 //=== Serialization/PCHContainerOperations.cpp - PCH Containers -*- 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 file defines PCHContainerOperations and RawPCHContainerOperation.
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/Serialization/PCHContainerOperations.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/Lex/ModuleLoader.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/raw_ostream.h"
 #include <utility>
 
 using namespace clang;
 
 PCHContainerWriter::~PCHContainerWriter() {}
 PCHContainerReader::~PCHContainerReader() {}
 

cfe/trunk/tools/libclang/CXLoadedDiagnostic.cpp

 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Frontend/SerializedDiagnosticReader.h"
 #include "clang/Frontend/SerializedDiagnostics.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/ErrorHandling.h"
 
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
 // Extend CXDiagnosticSetImpl which contains strings for diagnostics.
 //===----------------------------------------------------------------------===//
 

cfe/trunk/unittests/Serialization/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   BitReader
+  BitstreamReader
   Support
   )
 
 add_clang_unittest(SerializationTests
   InMemoryModuleCacheTest.cpp
   )
 
 target_link_libraries(SerializationTests
   PRIVATE
   clangAST
   clangBasic
   clangLex
   clangSema
   clangSerialization
   )

clang-tools-extra/trunk/clang-doc/BitcodeReader.h

 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
 
 #include "BitcodeWriter.h"
 #include "Representation.h"
 #include "clang/AST/AST.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Support/Error.h"
 
 namespace clang {
 namespace doc {
 
 // Class to read bitstream into an InfoSet collection
 class ClangDocBitcodeReader {
 public:

clang-tools-extra/trunk/clang-doc/BitcodeWriter.h

 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEWRITER_H
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEWRITER_H
 
 #include "Representation.h"
 #include "clang/AST/AST.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include <initializer_list>
 #include <vector>
 
 namespace clang {
 namespace doc {
 
 // Current version number of clang-doc bitcode.
 // Should be bumped when removing or changing BlockIds, RecordIds, or

clang-tools-extra/trunk/clang-doc/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   support
-  BitReader
-  BitWriter
+  BitstreamReader
   )
 
 add_clang_library(clangDoc
   BitcodeReader.cpp
   BitcodeWriter.cpp
   ClangDoc.cpp
   Generators.cpp
   Mapper.cpp

clang-tools-extra/trunk/unittests/clang-doc/BitcodeTest.cpp

 //===-- clang-doc/BitcodeTest.cpp -----------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "BitcodeReader.h"
 #include "BitcodeWriter.h"
 #include "ClangDocTest.h"
 #include "Representation.h"
-#include "llvm/Bitcode/BitstreamReader.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "gtest/gtest.h"
 
 namespace clang {
 namespace doc {
 
 template <typename T> static std::string writeInfo(T &I) {
   SmallString<2048> Buffer;
   llvm::BitstreamWriter Stream(Buffer);

clang-tools-extra/trunk/unittests/clang-doc/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   support
-  BitReader
-  BitWriter
+  BitstreamReader
   )
 
 get_filename_component(CLANG_DOC_SOURCE_DIR
   ${CMAKE_CURRENT_SOURCE_DIR}/../../clang-doc REALPATH)
 include_directories(
   ${CLANG_DOC_SOURCE_DIR}
   )
 

llvm/trunk/include/llvm/Bitcode/BitCodes.h

-//===- BitCodes.h - Enum values for the bitcode format ----------*- 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 Bitcode enum values.
-//
-// The enum values defined in this file should be considered permanent.  If
-// new features are added, they should have values added at the end of the
-// respective lists.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_BITCODE_BITCODES_H
-#define LLVM_BITCODE_BITCODES_H
-
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/Support/DataTypes.h"
-#include "llvm/Support/ErrorHandling.h"
-#include <cassert>
-
-namespace llvm {
-/// Offsets of the 32-bit fields of bitcode wrapper header.
-static const unsigned BWH_MagicField = 0 * 4;
-static const unsigned BWH_VersionField = 1 * 4;
-static const unsigned BWH_OffsetField = 2 * 4;
-static const unsigned BWH_SizeField = 3 * 4;
-static const unsigned BWH_CPUTypeField = 4 * 4;
-static const unsigned BWH_HeaderSize = 5 * 4;
-
-namespace bitc {
-  enum StandardWidths {
-    BlockIDWidth   = 8,  // We use VBR-8 for block IDs.
-    CodeLenWidth   = 4,  // Codelen are VBR-4.
-    BlockSizeWidth = 32  // BlockSize up to 2^32 32-bit words = 16GB per block.
-  };
-
-  // The standard abbrev namespace always has a way to exit a block, enter a
-  // nested block, define abbrevs, and define an unabbreviated record.
-  enum FixedAbbrevIDs {
-    END_BLOCK = 0,  // Must be zero to guarantee termination for broken bitcode.
-    ENTER_SUBBLOCK = 1,
-
-    /// DEFINE_ABBREV - Defines an abbrev for the current block.  It consists
-    /// of a vbr5 for # operand infos.  Each operand info is emitted with a
-    /// single bit to indicate if it is a literal encoding.  If so, the value is
-    /// emitted with a vbr8.  If not, the encoding is emitted as 3 bits followed
-    /// by the info value as a vbr5 if needed.
-    DEFINE_ABBREV = 2,
-
-    // UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
-    // a vbr6 for the # operands, followed by vbr6's for each operand.
-    UNABBREV_RECORD = 3,
-
-    // This is not a code, this is a marker for the first abbrev assignment.
-    FIRST_APPLICATION_ABBREV = 4
-  };
-
-  /// StandardBlockIDs - All bitcode files can optionally include a BLOCKINFO
-  /// block, which contains metadata about other blocks in the file.
-  enum StandardBlockIDs {
-    /// BLOCKINFO_BLOCK is used to define metadata about blocks, for example,
-    /// standard abbrevs that should be available to all blocks of a specified
-    /// ID.
-    BLOCKINFO_BLOCK_ID = 0,
-
-    // Block IDs 1-7 are reserved for future expansion.
-    FIRST_APPLICATION_BLOCKID = 8
-  };
-
-  /// BlockInfoCodes - The blockinfo block contains metadata about user-defined
-  /// blocks.
-  enum BlockInfoCodes {
-    // DEFINE_ABBREV has magic semantics here, applying to the current SETBID'd
-    // block, instead of the BlockInfo block.
-
-    BLOCKINFO_CODE_SETBID        = 1, // SETBID: [blockid#]
-    BLOCKINFO_CODE_BLOCKNAME     = 2, // BLOCKNAME: [name]
-    BLOCKINFO_CODE_SETRECORDNAME = 3  // BLOCKINFO_CODE_SETRECORDNAME:
-                                      //                             [id, name]
-  };
-
-} // End bitc namespace
-
-/// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
-/// This is actually a union of two different things:
-///   1. It could be a literal integer value ("the operand is always 17").
-///   2. It could be an encoding specification ("this operand encoded like so").
-///
-class BitCodeAbbrevOp {
-  uint64_t Val;           // A literal value or data for an encoding.
-  bool IsLiteral : 1;     // Indicate whether this is a literal value or not.
-  unsigned Enc   : 3;     // The encoding to use.
-public:
-  enum Encoding {
-    Fixed = 1,  // A fixed width field, Val specifies number of bits.
-    VBR   = 2,  // A VBR field where Val specifies the width of each chunk.
-    Array = 3,  // A sequence of fields, next field species elt encoding.
-    Char6 = 4,  // A 6-bit fixed field which maps to [a-zA-Z0-9._].
-    Blob  = 5   // 32-bit aligned array of 8-bit characters.
-  };
-
-  explicit BitCodeAbbrevOp(uint64_t V) :  Val(V), IsLiteral(true) {}
-  explicit BitCodeAbbrevOp(Encoding E, uint64_t Data = 0)
-    : Val(Data), IsLiteral(false), Enc(E) {}
-
-  bool isLiteral() const  { return IsLiteral; }
-  bool isEncoding() const { return !IsLiteral; }
-
-  // Accessors for literals.
-  uint64_t getLiteralValue() const { assert(isLiteral()); return Val; }
-
-  // Accessors for encoding info.
-  Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
-  uint64_t getEncodingData() const {
-    assert(isEncoding() && hasEncodingData());
-    return Val;
-  }
-
-  bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
-  static bool hasEncodingData(Encoding E) {
-    switch (E) {
-    case Fixed:
-    case VBR:
-      return true;
-    case Array:
-    case Char6:
-    case Blob:
-      return false;
-    }
-    report_fatal_error("Invalid encoding");
-  }
-
-  /// isChar6 - Return true if this character is legal in the Char6 encoding.
-  static bool isChar6(char C) {
-    if (C >= 'a' && C <= 'z') return true;
-    if (C >= 'A' && C <= 'Z') return true;
-    if (C >= '0' && C <= '9') return true;
-    if (C == '.' || C == '_') return true;
-    return false;
-  }
-  static unsigned EncodeChar6(char C) {
-    if (C >= 'a' && C <= 'z') return C-'a';
-    if (C >= 'A' && C <= 'Z') return C-'A'+26;
-    if (C >= '0' && C <= '9') return C-'0'+26+26;
-    if (C == '.')             return 62;
-    if (C == '_')             return 63;
-    llvm_unreachable("Not a value Char6 character!");
-  }
-
-  static char DecodeChar6(unsigned V) {
-    assert((V & ~63) == 0 && "Not a Char6 encoded character!");
-    return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789._"
-        [V];
-  }
-
-};
-
-/// BitCodeAbbrev - This class represents an abbreviation record.  An
-/// abbreviation allows a complex record that has redundancy to be stored in a
-/// specialized format instead of the fully-general, fully-vbr, format.
-class BitCodeAbbrev {
-  SmallVector<BitCodeAbbrevOp, 32> OperandList;
-
-public:
-  unsigned getNumOperandInfos() const {
-    return static_cast<unsigned>(OperandList.size());
-  }
-  const BitCodeAbbrevOp &getOperandInfo(unsigned N) const {
-    return OperandList[N];
-  }
-
-  void Add(const BitCodeAbbrevOp &OpInfo) {
-    OperandList.push_back(OpInfo);
-  }
-};
-} // End llvm namespace
-
-#endif

llvm/trunk/include/llvm/Bitcode/BitcodeReader.h

 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_BITCODE_BITCODEREADER_H
 #define LLVM_BITCODE_BITCODEREADER_H
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitCodes.h"
+#include "llvm/Bitstream/BitCodes.h"
 #include "llvm/IR/ModuleSummaryIndex.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include <cstdint>
 #include <memory>
 #include <string>

llvm/trunk/include/llvm/Bitcode/BitstreamReader.h

-//===- BitstreamReader.h - Low-level bitstream reader 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 BitstreamReader class.  This class can be used to
-// read an arbitrary bitstream, regardless of its contents.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_BITCODE_BITSTREAMREADER_H
-#define LLVM_BITCODE_BITSTREAMREADER_H
-
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/Bitcode/BitCodes.h"
-#include "llvm/Support/Endian.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/MathExtras.h"
-#include "llvm/Support/MemoryBuffer.h"
-#include <algorithm>
-#include <cassert>
-#include <climits>
-#include <cstddef>
-#include <cstdint>
-#include <memory>
-#include <string>
-#include <utility>
-#include <vector>
-
-namespace llvm {
-
-/// This class maintains the abbreviations read from a block info block.
-class BitstreamBlockInfo {
-public:
-  /// 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::string Name;
-    std::vector<std::pair<unsigned, std::string>> RecordNames;
-  };
-
-private:
-  std::vector<BlockInfo> BlockInfoRecords;
-
-public:
-  /// If there is block info for the specified ID, return it, otherwise return
-  /// null.
-  const BlockInfo *getBlockInfo(unsigned BlockID) const {
-    // Common case, the most recent entry matches BlockID.
-    if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
-      return &BlockInfoRecords.back();
-
-    for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
-         i != e; ++i)
-      if (BlockInfoRecords[i].BlockID == BlockID)
-        return &BlockInfoRecords[i];
-    return nullptr;
-  }
-
-  BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
-    if (const BlockInfo *BI = getBlockInfo(BlockID))
-      return *const_cast<BlockInfo*>(BI);
-
-    // Otherwise, add a new record.
-    BlockInfoRecords.emplace_back();
-    BlockInfoRecords.back().BlockID = BlockID;
-    return BlockInfoRecords.back();
-  }
-};
-
-/// This represents a position within a bitstream. There may be multiple
-/// independent cursors reading within one bitstream, each maintaining their
-/// own local state.
-class SimpleBitstreamCursor {
-  ArrayRef<uint8_t> BitcodeBytes;
-  size_t NextChar = 0;
-
-public:
-  /// This is the current data we have pulled from the stream but have not
-  /// returned to the client. This is specifically and intentionally defined to
-  /// follow the word size of the host machine for efficiency. We use word_t in
-  /// places that are aware of this to make it perfectly explicit what is going
-  /// on.
-  using word_t = size_t;
-
-private:
-  word_t CurWord = 0;
-
-  /// This is the number of bits in CurWord that are valid. This is always from
-  /// [0...bits_of(size_t)-1] inclusive.
-  unsigned BitsInCurWord = 0;
-
-public:
-  static const constexpr size_t MaxChunkSize = sizeof(word_t) * 8;
-
-  SimpleBitstreamCursor() = default;
-  explicit SimpleBitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
-      : BitcodeBytes(BitcodeBytes) {}
-  explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
-      : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
-  explicit SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
-      : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}
-
-  bool canSkipToPos(size_t pos) const {
-    // pos can be skipped to if it is a valid address or one byte past the end.
-    return pos <= BitcodeBytes.size();
-  }
-
-  bool AtEndOfStream() {
-    return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
-  }
-
-  /// Return the bit # of the bit we are reading.
-  uint64_t GetCurrentBitNo() const {
-    return NextChar*CHAR_BIT - BitsInCurWord;
-  }
-
-  // Return the byte # of the current bit.
-  uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }
-
-  ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }
-
-  /// Reset the stream to the specified bit number.
-  Error JumpToBit(uint64_t BitNo) {
-    size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
-    unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
-    assert(canSkipToPos(ByteNo) && "Invalid location");
-
-    // Move the cursor to the right word.
-    NextChar = ByteNo;
-    BitsInCurWord = 0;
-
-    // Skip over any bits that are already consumed.
-    if (WordBitNo) {
-      if (Expected<word_t> Res = Read(WordBitNo))
-        return Error::success();
-      else
-        return Res.takeError();
-    }
-
-    return Error::success();
-  }
-
-  /// Get a pointer into the bitstream at the specified byte offset.
-  const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
-    return BitcodeBytes.data() + ByteNo;
-  }
-
-  /// Get a pointer into the bitstream at the specified bit offset.
-  ///
-  /// The bit offset must be on a byte boundary.
-  const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
-    assert(!(BitNo % 8) && "Expected bit on byte boundary");
-    return getPointerToByte(BitNo / 8, NumBytes);
-  }
-
-  Error fillCurWord() {
-    if (NextChar >= BitcodeBytes.size())
-      return createStringError(std::errc::io_error,
-                               "Unexpected end of file reading %u of %u bytes",
-                               NextChar, BitcodeBytes.size());
-
-    // Read the next word from the stream.
-    const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
-    unsigned BytesRead;
-    if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
-      BytesRead = sizeof(word_t);
-      CurWord =
-          support::endian::read<word_t, support::little, support::unaligned>(
-              NextCharPtr);
-    } else {
-      // Short read.
-      BytesRead = BitcodeBytes.size() - NextChar;
-      CurWord = 0;
-      for (unsigned B = 0; B != BytesRead; ++B)
-        CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
-    }
-    NextChar += BytesRead;
-    BitsInCurWord = BytesRead * 8;
-    return Error::success();
-  }
-
-  Expected<word_t> Read(unsigned NumBits) {
-    static const unsigned BitsInWord = MaxChunkSize;
-
-    assert(NumBits && NumBits <= BitsInWord &&
-           "Cannot return zero or more than BitsInWord bits!");
-
-    static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
-
-    // If the field is fully contained by CurWord, return it quickly.
-    if (BitsInCurWord >= NumBits) {
-      word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
-
-      // Use a mask to avoid undefined behavior.
-      CurWord >>= (NumBits & Mask);
-
-      BitsInCurWord -= NumBits;
-      return R;
-    }
-
-    word_t R = BitsInCurWord ? CurWord : 0;
-    unsigned BitsLeft = NumBits - BitsInCurWord;
-
-    if (Error fillResult = fillCurWord())
-      return std::move(fillResult);
-
-    // If we run out of data, abort.
-    if (BitsLeft > BitsInCurWord)
-      return createStringError(std::errc::io_error,
-                               "Unexpected end of file reading %u of %u bits",
-                               BitsInCurWord, BitsLeft);
-
-    word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
-
-    // Use a mask to avoid undefined behavior.
-    CurWord >>= (BitsLeft & Mask);
-
-    BitsInCurWord -= BitsLeft;
-
-    R |= R2 << (NumBits - BitsLeft);
-
-    return R;
-  }
-
-  Expected<uint32_t> ReadVBR(unsigned NumBits) {
-    Expected<unsigned> MaybeRead = Read(NumBits);
-    if (!MaybeRead)
-      return MaybeRead;
-    uint32_t Piece = MaybeRead.get();
-
-    if ((Piece & (1U << (NumBits-1))) == 0)
-      return Piece;
-
-    uint32_t Result = 0;
-    unsigned NextBit = 0;
-    while (true) {
-      Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
-
-      if ((Piece & (1U << (NumBits-1))) == 0)
-        return Result;
-
-      NextBit += NumBits-1;
-      MaybeRead = Read(NumBits);
-      if (!MaybeRead)
-        return MaybeRead;
-      Piece = MaybeRead.get();
-    }
-  }
-
-  // Read a VBR that may have a value up to 64-bits in size. The chunk size of
-  // the VBR must still be <= 32 bits though.
-  Expected<uint64_t> ReadVBR64(unsigned NumBits) {
-    Expected<uint64_t> MaybeRead = Read(NumBits);
-    if (!MaybeRead)
-      return MaybeRead;
-    uint32_t Piece = MaybeRead.get();
-
-    if ((Piece & (1U << (NumBits-1))) == 0)
-      return uint64_t(Piece);
-
-    uint64_t Result = 0;
-    unsigned NextBit = 0;
-    while (true) {
-      Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
-
-      if ((Piece & (1U << (NumBits-1))) == 0)
-        return Result;
-
-      NextBit += NumBits-1;
-      MaybeRead = Read(NumBits);
-      if (!MaybeRead)
-        return MaybeRead;
-      Piece = MaybeRead.get();
-    }
-  }
-
-  void SkipToFourByteBoundary() {
-    // If word_t is 64-bits and if we've read less than 32 bits, just dump
-    // the bits we have up to the next 32-bit boundary.
-    if (sizeof(word_t) > 4 &&
-        BitsInCurWord >= 32) {
-      CurWord >>= BitsInCurWord-32;
-      BitsInCurWord = 32;
-      return;
-    }
-
-    BitsInCurWord = 0;
-  }
-
-  /// Skip to the end of the file.
-  void skipToEnd() { NextChar = BitcodeBytes.size(); }
-};
-
-/// When advancing through a bitstream cursor, each advance can discover a few
-/// different kinds of entries:
-struct BitstreamEntry {
-  enum {
-    Error,    // Malformed bitcode was found.
-    EndBlock, // We've reached the end of the current block, (or the end of the
-              // file, which is treated like a series of EndBlock records.
-    SubBlock, // This is the start of a new subblock of a specific ID.
-    Record    // This is a record with a specific AbbrevID.
-  } Kind;
-
-  unsigned ID;
-
-  static BitstreamEntry getError() {
-    BitstreamEntry E; E.Kind = Error; return E;
-  }
-
-  static BitstreamEntry getEndBlock() {
-    BitstreamEntry E; E.Kind = EndBlock; return E;
-  }
-
-  static BitstreamEntry getSubBlock(unsigned ID) {
-    BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
-  }
-
-  static BitstreamEntry getRecord(unsigned AbbrevID) {
-    BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
-  }
-};
-
-/// This represents a position within a bitcode file, implemented on top of a
-/// SimpleBitstreamCursor.
-///
-/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
-/// be passed by value.
-class BitstreamCursor : SimpleBitstreamCursor {
-  // This is the declared size of code values used for the current block, in
-  // bits.
-  unsigned CurCodeSize = 2;
-
-  /// Abbrevs installed at in this block.
-  std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
-
-  struct Block {
-    unsigned PrevCodeSize;
-    std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
-
-    explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
-  };
-
-  /// This tracks the codesize of parent blocks.
-  SmallVector<Block, 8> BlockScope;
-
-  BitstreamBlockInfo *BlockInfo = nullptr;
-
-public:
-  static const size_t MaxChunkSize = sizeof(word_t) * 8;
-
-  BitstreamCursor() = default;
-  explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
-      : SimpleBitstreamCursor(BitcodeBytes) {}
-  explicit BitstreamCursor(StringRef BitcodeBytes)
-      : SimpleBitstreamCursor(BitcodeBytes) {}
-  explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
-      : SimpleBitstreamCursor(BitcodeBytes) {}
-
-  using SimpleBitstreamCursor::canSkipToPos;
-  using SimpleBitstreamCursor::AtEndOfStream;
-  using SimpleBitstreamCursor::getBitcodeBytes;
-  using SimpleBitstreamCursor::GetCurrentBitNo;
-  using SimpleBitstreamCursor::getCurrentByteNo;
-  using SimpleBitstreamCursor::getPointerToByte;
-  using SimpleBitstreamCursor::JumpToBit;
-  using SimpleBitstreamCursor::fillCurWord;
-  using SimpleBitstreamCursor::Read;
-  using SimpleBitstreamCursor::ReadVBR;
-  using SimpleBitstreamCursor::ReadVBR64;
-
-  /// Return the number of bits used to encode an abbrev #.
-  unsigned getAbbrevIDWidth() const { return CurCodeSize; }
-
-  /// Flags that modify the behavior of advance().
-  enum {
-    /// If this flag is used, the advance() method does not automatically pop
-    /// the block scope when the end of a block is reached.
-    AF_DontPopBlockAtEnd = 1,
-
-    /// If this flag is used, abbrev entries are returned just like normal
-    /// records.
-    AF_DontAutoprocessAbbrevs = 2
-  };
-
-  /// Advance the current bitstream, returning the next entry in the stream.
-  Expected<BitstreamEntry> advance(unsigned Flags = 0) {
-    while (true) {
-      if (AtEndOfStream())
-        return BitstreamEntry::getError();
-
-      Expected<unsigned> MaybeCode = ReadCode();
-      if (!MaybeCode)
-        return MaybeCode.takeError();
-      unsigned Code = MaybeCode.get();
-
-      if (Code == bitc::END_BLOCK) {
-        // Pop the end of the block unless Flags tells us not to.
-        if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
-          return BitstreamEntry::getError();
-        return BitstreamEntry::getEndBlock();
-      }
-
-      if (Code == bitc::ENTER_SUBBLOCK) {
-        if (Expected<unsigned> MaybeSubBlock = ReadSubBlockID())
-          return BitstreamEntry::getSubBlock(MaybeSubBlock.get());
-        else
-          return MaybeSubBlock.takeError();
-      }
-
-      if (Code == bitc::DEFINE_ABBREV &&
-          !(Flags & AF_DontAutoprocessAbbrevs)) {
-        // We read and accumulate abbrev's, the client can't do anything with
-        // them anyway.
-        if (Error Err = ReadAbbrevRecord())
-          return std::move(Err);
-        continue;
-      }
-
-      return BitstreamEntry::getRecord(Code);
-    }
-  }
-
-  /// This is a convenience function for clients that don't expect any
-  /// subblocks. This just skips over them automatically.
-  Expected<BitstreamEntry> advanceSkippingSubblocks(unsigned Flags = 0) {
-    while (true) {
-      // If we found a normal entry, return it.
-      Expected<BitstreamEntry> MaybeEntry = advance(Flags);
-      if (!MaybeEntry)
-        return MaybeEntry;
-      BitstreamEntry Entry = MaybeEntry.get();
-
-      if (Entry.Kind != BitstreamEntry::SubBlock)
-        return Entry;
-
-      // If we found a sub-block, just skip over it and check the next entry.
-      if (Error Err = SkipBlock())
-        return std::move(Err);
-    }
-  }
-
-  Expected<unsigned> ReadCode() { return Read(CurCodeSize); }
-
-  // Block header:
-  //    [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
-
-  /// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
-  Expected<unsigned> ReadSubBlockID() { return ReadVBR(bitc::BlockIDWidth); }
-
-  /// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
-  /// of this block.
-  Error SkipBlock() {
-    // Read and ignore the codelen value.
-    if (Expected<uint32_t> Res = ReadVBR(bitc::CodeLenWidth))
-      ; // Since we are skipping this block, we don't care what code widths are
-        // used inside of it.
-    else
-      return Res.takeError();
-
-    SkipToFourByteBoundary();
-    Expected<unsigned> MaybeNum = Read(bitc::BlockSizeWidth);
-    if (!MaybeNum)
-      return MaybeNum.takeError();
-    size_t NumFourBytes = MaybeNum.get();
-
-    // Check that the block wasn't partially defined, and that the offset isn't
-    // bogus.
-    size_t SkipTo = GetCurrentBitNo() + NumFourBytes * 4 * 8;
-    if (AtEndOfStream())
-      return createStringError(std::errc::illegal_byte_sequence,
-                               "can't skip block: already at end of stream");
-    if (!canSkipToPos(SkipTo / 8))
-      return createStringError(std::errc::illegal_byte_sequence,
-                               "can't skip to bit %zu from %" PRIu64, SkipTo,
-                               GetCurrentBitNo());
-
-    if (Error Res = JumpToBit(SkipTo))
-      return Res;
-
-    return Error::success();
-  }
-
-  /// Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
-  Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
-
-  bool ReadBlockEnd() {
-    if (BlockScope.empty()) return true;
-
-    // Block tail:
-    //    [END_BLOCK, <align4bytes>]
-    SkipToFourByteBoundary();
-
-    popBlockScope();
-    return false;
-  }
-
-private:
-  void popBlockScope() {
-    CurCodeSize = BlockScope.back().PrevCodeSize;
-
-    CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
-    BlockScope.pop_back();
-  }
-
-  //===--------------------------------------------------------------------===//
-  // Record Processing
-  //===--------------------------------------------------------------------===//
-
-public:
-  /// Return the abbreviation for the specified AbbrevId.
-  const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
-    unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
-    if (AbbrevNo >= CurAbbrevs.size())
-      report_fatal_error("Invalid abbrev number");
-    return CurAbbrevs[AbbrevNo].get();
-  }
-
-  /// Read the current record and discard it, returning the code for the record.
-  Expected<unsigned> skipRecord(unsigned AbbrevID);
-
-  Expected<unsigned> readRecord(unsigned AbbrevID,
-                                SmallVectorImpl<uint64_t> &Vals,
-                                StringRef *Blob = nullptr);
-
-  //===--------------------------------------------------------------------===//
-  // Abbrev Processing
-  //===--------------------------------------------------------------------===//
-  Error ReadAbbrevRecord();
-
-  /// Read and return a block info block from the bitstream. If an error was
-  /// encountered, return None.
-  ///
-  /// \param ReadBlockInfoNames Whether to read block/record name information in
-  /// the BlockInfo block. Only llvm-bcanalyzer uses this.
-  Expected<Optional<BitstreamBlockInfo>>
-  ReadBlockInfoBlock(bool ReadBlockInfoNames = false);
-
-  /// Set the block info to be used by this BitstreamCursor to interpret
-  /// abbreviated records.
-  void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
-};
-
-} // end llvm namespace
-
-#endif // LLVM_BITCODE_BITSTREAMREADER_H

llvm/trunk/include/llvm/Bitcode/BitstreamWriter.h

-//===- 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_BITCODE_BITSTREAMWRITER_H
-#define LLVM_BITCODE_BITSTREAMWRITER_H
-
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Bitcode/BitCodes.h"
-#include "llvm/Support/Endian.h"
-#include <vector>
-
-namespace llvm {
-
-class BitstreamWriter {
-  SmallVectorImpl<char> &Out;
-
-  /// 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 WriteByte(unsigned char Value) {
-    Out.push_back(Value);
-  }
-
-  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));
-  }
-
-  size_t GetBufferOffset() const { return Out.size(); }
-
-  size_t GetWordIndex() const {
-    size_t Offset = GetBufferOffset();
-    assert((Offset & 3) == 0 && "Not 32-bit aligned");
-    return Offset / 4;
-  }
-
-public:
-  explicit BitstreamWriter(SmallVectorImpl<char> &O)
-    : Out(O), 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;
-    unsigned ByteNo = BitNo / 8;
-    assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>(
-               &Out[ByteNo], BitNo & 7)) &&
-           "Expected to be patching over 0-value placeholders");
-    endian::writeAtBitAlignment<uint32_t, little, unaligned>(
-        &Out[ByteNo], NewWord, BitNo & 7);
-  }
-
-  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 (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
-         i != e; ++i)
-      if (BlockInfoRecords[i].BlockID == BlockID)
-        return &BlockInfoRecords[i];
-    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)) {
-      CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
-                        Info->Abbrevs.end());
-    }
-  }
-
-  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();
-  }
-
-  //===--------------------------------------------------------------------===//
-  // 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, 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.getValue());
-      else {
-        assert(Op.getEncoding() != BitCodeAbbrevOp::Array &&
-               Op.getEncoding() != BitCodeAbbrevOp::Blob &&
-               "Expected literal or scalar");
-        EmitAbbreviatedField(Op, Code.getValue());
-      }
-    }
-
-    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.
-    for (const auto &B : Bytes) {
-      assert(isUInt<8>(B) && "Value too large to emit as byte");
-      WriteByte((unsigned char)B);
-    }
-
-    // Align end to 32-bits.
-    while (GetBufferOffset() & 3)
-      WriteByte(0);
-  }
-  void emitBlob(StringRef Bytes, bool ShouldEmitSize = true) {
-    emitBlob(makeArrayRef((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>(makeArrayRef(Vals).size());
-      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, makeArrayRef(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, makeArrayRef(Vals), StringRef(), None);
-  }
-
-  /// 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, makeArrayRef(Vals), Blob, None);
-  }
-  template <typename Container>
-  void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals,
-                          const char *BlobData, unsigned BlobLen) {
-    return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
-                                    StringRef(BlobData, BlobLen), None);
-  }
-
-  /// 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, makeArrayRef(Vals), Array, None);
-  }
-  template <typename Container>
-  void EmitRecordWithArray(unsigned Abbrev, const Container &Vals,
-                           const char *ArrayData, unsigned ArrayLen) {
-    return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
-                                    StringRef(ArrayData, ArrayLen), None);
-  }
-
-  //===--------------------------------------------------------------------===//
-  // 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

llvm/trunk/include/llvm/Bitcode/LLVMBitCodes.h

 // new features are added, they should have values added at the end of the
 // respective lists.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_BITCODE_LLVMBITCODES_H
 #define LLVM_BITCODE_LLVMBITCODES_H
 
-#include "llvm/Bitcode/BitCodes.h"
+#include "llvm/Bitstream/BitCodes.h"
 
 namespace llvm {
 namespace bitc {
 // The only top-level block types are MODULE, IDENTIFICATION, STRTAB and SYMTAB.
 enum BlockIDs {
   // Blocks
   MODULE_BLOCK_ID = FIRST_APPLICATION_BLOCKID,
 

llvm/trunk/include/llvm/Bitstream/BitCodes.h

+//===- BitCodes.h - Enum values for the bitstream format --------*- 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 bitstream enum values.
+//
+// The enum values defined in this file should be considered permanent.  If
+// new features are added, they should have values added at the end of the
+// respective lists.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITSTREAM_BITCODES_H
+#define LLVM_BITSTREAM_BITCODES_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <cassert>
+
+namespace llvm {
+/// Offsets of the 32-bit fields of bitstream wrapper header.
+static const unsigned BWH_MagicField = 0 * 4;
+static const unsigned BWH_VersionField = 1 * 4;
+static const unsigned BWH_OffsetField = 2 * 4;
+static const unsigned BWH_SizeField = 3 * 4;
+static const unsigned BWH_CPUTypeField = 4 * 4;
+static const unsigned BWH_HeaderSize = 5 * 4;
+
+namespace bitc {
+  enum StandardWidths {
+    BlockIDWidth   = 8,  // We use VBR-8 for block IDs.
+    CodeLenWidth   = 4,  // Codelen are VBR-4.
+    BlockSizeWidth = 32  // BlockSize up to 2^32 32-bit words = 16GB per block.
+  };
+
+  // The standard abbrev namespace always has a way to exit a block, enter a
+  // nested block, define abbrevs, and define an unabbreviated record.
+  enum FixedAbbrevIDs {
+    END_BLOCK = 0,  // Must be zero to guarantee termination for broken bitcode.
+    ENTER_SUBBLOCK = 1,
+
+    /// DEFINE_ABBREV - Defines an abbrev for the current block.  It consists
+    /// of a vbr5 for # operand infos.  Each operand info is emitted with a
+    /// single bit to indicate if it is a literal encoding.  If so, the value is
+    /// emitted with a vbr8.  If not, the encoding is emitted as 3 bits followed
+    /// by the info value as a vbr5 if needed.
+    DEFINE_ABBREV = 2,
+
+    // UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
+    // a vbr6 for the # operands, followed by vbr6's for each operand.
+    UNABBREV_RECORD = 3,
+
+    // This is not a code, this is a marker for the first abbrev assignment.
+    FIRST_APPLICATION_ABBREV = 4
+  };
+
+  /// StandardBlockIDs - All bitcode files can optionally include a BLOCKINFO
+  /// block, which contains metadata about other blocks in the file.
+  enum StandardBlockIDs {
+    /// BLOCKINFO_BLOCK is used to define metadata about blocks, for example,
+    /// standard abbrevs that should be available to all blocks of a specified
+    /// ID.
+    BLOCKINFO_BLOCK_ID = 0,
+
+    // Block IDs 1-7 are reserved for future expansion.
+    FIRST_APPLICATION_BLOCKID = 8
+  };
+
+  /// BlockInfoCodes - The blockinfo block contains metadata about user-defined
+  /// blocks.
+  enum BlockInfoCodes {
+    // DEFINE_ABBREV has magic semantics here, applying to the current SETBID'd
+    // block, instead of the BlockInfo block.
+
+    BLOCKINFO_CODE_SETBID        = 1, // SETBID: [blockid#]
+    BLOCKINFO_CODE_BLOCKNAME     = 2, // BLOCKNAME: [name]
+    BLOCKINFO_CODE_SETRECORDNAME = 3  // BLOCKINFO_CODE_SETRECORDNAME:
+                                      //                             [id, name]
+  };
+
+} // End bitc namespace
+
+/// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
+/// This is actually a union of two different things:
+///   1. It could be a literal integer value ("the operand is always 17").
+///   2. It could be an encoding specification ("this operand encoded like so").
+///
+class BitCodeAbbrevOp {
+  uint64_t Val;           // A literal value or data for an encoding.
+  bool IsLiteral : 1;     // Indicate whether this is a literal value or not.
+  unsigned Enc   : 3;     // The encoding to use.
+public:
+  enum Encoding {
+    Fixed = 1,  // A fixed width field, Val specifies number of bits.
+    VBR   = 2,  // A VBR field where Val specifies the width of each chunk.
+    Array = 3,  // A sequence of fields, next field species elt encoding.
+    Char6 = 4,  // A 6-bit fixed field which maps to [a-zA-Z0-9._].
+    Blob  = 5   // 32-bit aligned array of 8-bit characters.
+  };
+
+  explicit BitCodeAbbrevOp(uint64_t V) :  Val(V), IsLiteral(true) {}
+  explicit BitCodeAbbrevOp(Encoding E, uint64_t Data = 0)
+    : Val(Data), IsLiteral(false), Enc(E) {}
+
+  bool isLiteral() const  { return IsLiteral; }
+  bool isEncoding() const { return !IsLiteral; }
+
+  // Accessors for literals.
+  uint64_t getLiteralValue() const { assert(isLiteral()); return Val; }
+
+  // Accessors for encoding info.
+  Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
+  uint64_t getEncodingData() const {
+    assert(isEncoding() && hasEncodingData());
+    return Val;
+  }
+
+  bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
+  static bool hasEncodingData(Encoding E) {
+    switch (E) {
+    case Fixed:
+    case VBR:
+      return true;
+    case Array:
+    case Char6:
+    case Blob:
+      return false;
+    }
+    report_fatal_error("Invalid encoding");
+  }
+
+  /// isChar6 - Return true if this character is legal in the Char6 encoding.
+  static bool isChar6(char C) {
+    if (C >= 'a' && C <= 'z') return true;
+    if (C >= 'A' && C <= 'Z') return true;
+    if (C >= '0' && C <= '9') return true;
+    if (C == '.' || C == '_') return true;
+    return false;
+  }
+  static unsigned EncodeChar6(char C) {
+    if (C >= 'a' && C <= 'z') return C-'a';
+    if (C >= 'A' && C <= 'Z') return C-'A'+26;
+    if (C >= '0' && C <= '9') return C-'0'+26+26;
+    if (C == '.')             return 62;
+    if (C == '_')             return 63;
+    llvm_unreachable("Not a value Char6 character!");
+  }
+
+  static char DecodeChar6(unsigned V) {
+    assert((V & ~63) == 0 && "Not a Char6 encoded character!");
+    return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789._"
+        [V];
+  }
+
+};
+
+/// BitCodeAbbrev - This class represents an abbreviation record.  An
+/// abbreviation allows a complex record that has redundancy to be stored in a
+/// specialized format instead of the fully-general, fully-vbr, format.
+class BitCodeAbbrev {
+  SmallVector<BitCodeAbbrevOp, 32> OperandList;
+
+public:
+  unsigned getNumOperandInfos() const {
+    return static_cast<unsigned>(OperandList.size());
+  }
+  const BitCodeAbbrevOp &getOperandInfo(unsigned N) const {
+    return OperandList[N];
+  }
+
+  void Add(const BitCodeAbbrevOp &OpInfo) {
+    OperandList.push_back(OpInfo);
+  }
+};
+} // End llvm namespace
+
+#endif

llvm/trunk/include/llvm/Bitstream/BitstreamReader.h

+//===- BitstreamReader.h - Low-level bitstream reader 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 BitstreamReader class.  This class can be used to
+// read an arbitrary bitstream, regardless of its contents.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITSTREAM_BITSTREAMREADER_H
+#define LLVM_BITSTREAM_BITSTREAMREADER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Bitstream/BitCodes.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <algorithm>
+#include <cassert>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+/// This class maintains the abbreviations read from a block info block.
+class BitstreamBlockInfo {
+public:
+  /// 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::string Name;
+    std::vector<std::pair<unsigned, std::string>> RecordNames;
+  };
+
+private:
+  std::vector<BlockInfo> BlockInfoRecords;
+
+public:
+  /// If there is block info for the specified ID, return it, otherwise return
+  /// null.
+  const BlockInfo *getBlockInfo(unsigned BlockID) const {
+    // Common case, the most recent entry matches BlockID.
+    if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
+      return &BlockInfoRecords.back();
+
+    for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
+         i != e; ++i)
+      if (BlockInfoRecords[i].BlockID == BlockID)
+        return &BlockInfoRecords[i];
+    return nullptr;
+  }
+
+  BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
+    if (const BlockInfo *BI = getBlockInfo(BlockID))
+      return *const_cast<BlockInfo*>(BI);
+
+    // Otherwise, add a new record.
+    BlockInfoRecords.emplace_back();
+    BlockInfoRecords.back().BlockID = BlockID;
+    return BlockInfoRecords.back();
+  }
+};
+
+/// This represents a position within a bitstream. There may be multiple
+/// independent cursors reading within one bitstream, each maintaining their
+/// own local state.
+class SimpleBitstreamCursor {
+  ArrayRef<uint8_t> BitcodeBytes;
+  size_t NextChar = 0;
+
+public:
+  /// This is the current data we have pulled from the stream but have not
+  /// returned to the client. This is specifically and intentionally defined to
+  /// follow the word size of the host machine for efficiency. We use word_t in
+  /// places that are aware of this to make it perfectly explicit what is going
+  /// on.
+  using word_t = size_t;
+
+private:
+  word_t CurWord = 0;
+
+  /// This is the number of bits in CurWord that are valid. This is always from
+  /// [0...bits_of(size_t)-1] inclusive.
+  unsigned BitsInCurWord = 0;
+
+public:
+  static const constexpr size_t MaxChunkSize = sizeof(word_t) * 8;
+
+  SimpleBitstreamCursor() = default;
+  explicit SimpleBitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
+      : BitcodeBytes(BitcodeBytes) {}
+  explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
+      : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
+  explicit SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
+      : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}
+
+  bool canSkipToPos(size_t pos) const {
+    // pos can be skipped to if it is a valid address or one byte past the end.
+    return pos <= BitcodeBytes.size();
+  }
+
+  bool AtEndOfStream() {
+    return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
+  }
+
+  /// Return the bit # of the bit we are reading.
+  uint64_t GetCurrentBitNo() const {
+    return NextChar*CHAR_BIT - BitsInCurWord;
+  }
+
+  // Return the byte # of the current bit.
+  uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }
+
+  ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }
+
+  /// Reset the stream to the specified bit number.
+  Error JumpToBit(uint64_t BitNo) {
+    size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
+    unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
+    assert(canSkipToPos(ByteNo) && "Invalid location");
+
+    // Move the cursor to the right word.
+    NextChar = ByteNo;
+    BitsInCurWord = 0;
+
+    // Skip over any bits that are already consumed.
+    if (WordBitNo) {
+      if (Expected<word_t> Res = Read(WordBitNo))
+        return Error::success();
+      else
+        return Res.takeError();
+    }
+
+    return Error::success();
+  }
+
+  /// Get a pointer into the bitstream at the specified byte offset.
+  const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
+    return BitcodeBytes.data() + ByteNo;
+  }
+
+  /// Get a pointer into the bitstream at the specified bit offset.
+  ///
+  /// The bit offset must be on a byte boundary.
+  const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
+    assert(!(BitNo % 8) && "Expected bit on byte boundary");
+    return getPointerToByte(BitNo / 8, NumBytes);
+  }
+
+  Error fillCurWord() {
+    if (NextChar >= BitcodeBytes.size())
+      return createStringError(std::errc::io_error,
+                               "Unexpected end of file reading %u of %u bytes",
+                               NextChar, BitcodeBytes.size());
+
+    // Read the next word from the stream.
+    const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
+    unsigned BytesRead;
+    if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
+      BytesRead = sizeof(word_t);
+      CurWord =
+          support::endian::read<word_t, support::little, support::unaligned>(
+              NextCharPtr);
+    } else {
+      // Short read.
+      BytesRead = BitcodeBytes.size() - NextChar;
+      CurWord = 0;
+      for (unsigned B = 0; B != BytesRead; ++B)
+        CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
+    }
+    NextChar += BytesRead;
+    BitsInCurWord = BytesRead * 8;
+    return Error::success();
+  }
+
+  Expected<word_t> Read(unsigned NumBits) {
+    static const unsigned BitsInWord = MaxChunkSize;
+
+    assert(NumBits && NumBits <= BitsInWord &&
+           "Cannot return zero or more than BitsInWord bits!");
+
+    static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
+
+    // If the field is fully contained by CurWord, return it quickly.
+    if (BitsInCurWord >= NumBits) {
+      word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
+
+      // Use a mask to avoid undefined behavior.
+      CurWord >>= (NumBits & Mask);
+
+      BitsInCurWord -= NumBits;
+      return R;
+    }
+
+    word_t R = BitsInCurWord ? CurWord : 0;
+    unsigned BitsLeft = NumBits - BitsInCurWord;
+
+    if (Error fillResult = fillCurWord())
+      return std::move(fillResult);
+
+    // If we run out of data, abort.
+    if (BitsLeft > BitsInCurWord)
+      return createStringError(std::errc::io_error,
+                               "Unexpected end of file reading %u of %u bits",
+                               BitsInCurWord, BitsLeft);
+
+    word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
+
+    // Use a mask to avoid undefined behavior.
+    CurWord >>= (BitsLeft & Mask);
+
+    BitsInCurWord -= BitsLeft;
+
+    R |= R2 << (NumBits - BitsLeft);
+
+    return R;
+  }
+
+  Expected<uint32_t> ReadVBR(unsigned NumBits) {
+    Expected<unsigned> MaybeRead = Read(NumBits);
+    if (!MaybeRead)
+      return MaybeRead;
+    uint32_t Piece = MaybeRead.get();
+
+    if ((Piece & (1U << (NumBits-1))) == 0)
+      return Piece;
+
+    uint32_t Result = 0;
+    unsigned NextBit = 0;
+    while (true) {
+      Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
+
+      if ((Piece & (1U << (NumBits-1))) == 0)
+        return Result;
+
+      NextBit += NumBits-1;
+      MaybeRead = Read(NumBits);
+      if (!MaybeRead)
+        return MaybeRead;
+      Piece = MaybeRead.get();
+    }
+  }
+
+  // Read a VBR that may have a value up to 64-bits in size. The chunk size of
+  // the VBR must still be <= 32 bits though.
+  Expected<uint64_t> ReadVBR64(unsigned NumBits) {
+    Expected<uint64_t> MaybeRead = Read(NumBits);
+    if (!MaybeRead)
+      return MaybeRead;
+    uint32_t Piece = MaybeRead.get();
+
+    if ((Piece & (1U << (NumBits-1))) == 0)
+      return uint64_t(Piece);
+
+    uint64_t Result = 0;
+    unsigned NextBit = 0;
+    while (true) {
+      Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
+
+      if ((Piece & (1U << (NumBits-1))) == 0)
+        return Result;
+
+      NextBit += NumBits-1;
+      MaybeRead = Read(NumBits);
+      if (!MaybeRead)
+        return MaybeRead;
+      Piece = MaybeRead.get();
+    }
+  }
+
+  void SkipToFourByteBoundary() {
+    // If word_t is 64-bits and if we've read less than 32 bits, just dump
+    // the bits we have up to the next 32-bit boundary.
+    if (sizeof(word_t) > 4 &&
+        BitsInCurWord >= 32) {
+      CurWord >>= BitsInCurWord-32;
+      BitsInCurWord = 32;
+      return;
+    }
+
+    BitsInCurWord = 0;
+  }
+
+  /// Skip to the end of the file.
+  void skipToEnd() { NextChar = BitcodeBytes.size(); }
+};
+
+/// When advancing through a bitstream cursor, each advance can discover a few
+/// different kinds of entries:
+struct BitstreamEntry {
+  enum {
+    Error,    // Malformed bitcode was found.
+    EndBlock, // We've reached the end of the current block, (or the end of the
+              // file, which is treated like a series of EndBlock records.
+    SubBlock, // This is the start of a new subblock of a specific ID.
+    Record    // This is a record with a specific AbbrevID.
+  } Kind;
+
+  unsigned ID;
+
+  static BitstreamEntry getError() {
+    BitstreamEntry E; E.Kind = Error; return E;
+  }
+
+  static BitstreamEntry getEndBlock() {
+    BitstreamEntry E; E.Kind = EndBlock; return E;
+  }
+
+  static BitstreamEntry getSubBlock(unsigned ID) {
+    BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
+  }
+
+  static BitstreamEntry getRecord(unsigned AbbrevID) {
+    BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
+  }
+};
+
+/// This represents a position within a bitcode file, implemented on top of a
+/// SimpleBitstreamCursor.
+///
+/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
+/// be passed by value.
+class BitstreamCursor : SimpleBitstreamCursor {
+  // This is the declared size of code values used for the current block, in
+  // bits.
+  unsigned CurCodeSize = 2;
+
+  /// Abbrevs installed at in this block.
+  std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;
+
+  struct Block {
+    unsigned PrevCodeSize;
+    std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;
+
+    explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
+  };
+
+  /// This tracks the codesize of parent blocks.
+  SmallVector<Block, 8> BlockScope;
+
+  BitstreamBlockInfo *BlockInfo = nullptr;
+
+public:
+  static const size_t MaxChunkSize = sizeof(word_t) * 8;
+
+  BitstreamCursor() = default;
+  explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
+      : SimpleBitstreamCursor(BitcodeBytes) {}
+  explicit BitstreamCursor(StringRef BitcodeBytes)
+      : SimpleBitstreamCursor(BitcodeBytes) {}
+  explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
+      : SimpleBitstreamCursor(BitcodeBytes) {}
+
+  using SimpleBitstreamCursor::canSkipToPos;
+  using SimpleBitstreamCursor::AtEndOfStream;
+  using SimpleBitstreamCursor::getBitcodeBytes;
+  using SimpleBitstreamCursor::GetCurrentBitNo;
+  using SimpleBitstreamCursor::getCurrentByteNo;
+  using SimpleBitstreamCursor::getPointerToByte;
+  using SimpleBitstreamCursor::JumpToBit;
+  using SimpleBitstreamCursor::fillCurWord;
+  using SimpleBitstreamCursor::Read;
+  using SimpleBitstreamCursor::ReadVBR;
+  using SimpleBitstreamCursor::ReadVBR64;
+
+  /// Return the number of bits used to encode an abbrev #.
+  unsigned getAbbrevIDWidth() const { return CurCodeSize; }
+
+  /// Flags that modify the behavior of advance().
+  enum {
+    /// If this flag is used, the advance() method does not automatically pop
+    /// the block scope when the end of a block is reached.
+    AF_DontPopBlockAtEnd = 1,
+
+    /// If this flag is used, abbrev entries are returned just like normal
+    /// records.
+    AF_DontAutoprocessAbbrevs = 2
+  };
+
+  /// Advance the current bitstream, returning the next entry in the stream.
+  Expected<BitstreamEntry> advance(unsigned Flags = 0) {
+    while (true) {
+      if (AtEndOfStream())
+        return BitstreamEntry::getError();
+
+      Expected<unsigned> MaybeCode = ReadCode();
+      if (!MaybeCode)
+        return MaybeCode.takeError();
+      unsigned Code = MaybeCode.get();
+
+      if (Code == bitc::END_BLOCK) {
+        // Pop the end of the block unless Flags tells us not to.
+        if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
+          return BitstreamEntry::getError();
+        return BitstreamEntry::getEndBlock();
+      }
+
+      if (Code == bitc::ENTER_SUBBLOCK) {
+        if (Expected<unsigned> MaybeSubBlock = ReadSubBlockID())
+          return BitstreamEntry::getSubBlock(MaybeSubBlock.get());
+        else
+          return MaybeSubBlock.takeError();
+      }
+
+      if (Code == bitc::DEFINE_ABBREV &&
+          !(Flags & AF_DontAutoprocessAbbrevs)) {
+        // We read and accumulate abbrev's, the client can't do anything with
+        // them anyway.
+        if (Error Err = ReadAbbrevRecord())
+          return std::move(Err);
+        continue;
+      }
+
+      return BitstreamEntry::getRecord(Code);
+    }
+  }
+
+  /// This is a convenience function for clients that don't expect any
+  /// subblocks. This just skips over them automatically.
+  Expected<BitstreamEntry> advanceSkippingSubblocks(unsigned Flags = 0) {
+    while (true) {
+      // If we found a normal entry, return it.
+      Expected<BitstreamEntry> MaybeEntry = advance(Flags);
+      if (!MaybeEntry)
+        return MaybeEntry;
+      BitstreamEntry Entry = MaybeEntry.get();
+
+      if (Entry.Kind != BitstreamEntry::SubBlock)
+        return Entry;
+
+      // If we found a sub-block, just skip over it and check the next entry.
+      if (Error Err = SkipBlock())
+        return std::move(Err);
+    }
+  }
+
+  Expected<unsigned> ReadCode() { return Read(CurCodeSize); }
+
+  // Block header:
+  //    [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
+
+  /// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
+  Expected<unsigned> ReadSubBlockID() { return ReadVBR(bitc::BlockIDWidth); }
+
+  /// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
+  /// of this block.
+  Error SkipBlock() {
+    // Read and ignore the codelen value.
+    if (Expected<uint32_t> Res = ReadVBR(bitc::CodeLenWidth))
+      ; // Since we are skipping this block, we don't care what code widths are
+        // used inside of it.
+    else
+      return Res.takeError();
+
+    SkipToFourByteBoundary();
+    Expected<unsigned> MaybeNum = Read(bitc::BlockSizeWidth);
+    if (!MaybeNum)
+      return MaybeNum.takeError();
+    size_t NumFourBytes = MaybeNum.get();
+
+    // Check that the block wasn't partially defined, and that the offset isn't
+    // bogus.
+    size_t SkipTo = GetCurrentBitNo() + NumFourBytes * 4 * 8;
+    if (AtEndOfStream())
+      return createStringError(std::errc::illegal_byte_sequence,
+                               "can't skip block: already at end of stream");
+    if (!canSkipToPos(SkipTo / 8))
+      return createStringError(std::errc::illegal_byte_sequence,
+                               "can't skip to bit %zu from %" PRIu64, SkipTo,
+                               GetCurrentBitNo());
+
+    if (Error Res = JumpToBit(SkipTo))
+      return Res;
+
+    return Error::success();
+  }
+
+  /// Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
+  Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
+
+  bool ReadBlockEnd() {
+    if (BlockScope.empty()) return true;
+
+    // Block tail:
+    //    [END_BLOCK, <align4bytes>]
+    SkipToFourByteBoundary();
+
+    popBlockScope();
+    return false;
+  }
+
+private:
+  void popBlockScope() {
+    CurCodeSize = BlockScope.back().PrevCodeSize;
+
+    CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
+    BlockScope.pop_back();
+  }
+
+  //===--------------------------------------------------------------------===//
+  // Record Processing
+  //===--------------------------------------------------------------------===//
+
+public:
+  /// Return the abbreviation for the specified AbbrevId.
+  const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
+    unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
+    if (AbbrevNo >= CurAbbrevs.size())
+      report_fatal_error("Invalid abbrev number");
+    return CurAbbrevs[AbbrevNo].get();
+  }
+
+  /// Read the current record and discard it, returning the code for the record.
+  Expected<unsigned> skipRecord(unsigned AbbrevID);
+
+  Expected<unsigned> readRecord(unsigned AbbrevID,
+                                SmallVectorImpl<uint64_t> &Vals,
+                                StringRef *Blob = nullptr);
+
+  //===--------------------------------------------------------------------===//
+  // Abbrev Processing
+  //===--------------------------------------------------------------------===//
+  Error ReadAbbrevRecord();
+
+  /// Read and return a block info block from the bitstream. If an error was
+  /// encountered, return None.
+  ///
+  /// \param ReadBlockInfoNames Whether to read block/record name information in
+  /// the BlockInfo block. Only llvm-bcanalyzer uses this.
+  Expected<Optional<BitstreamBlockInfo>>
+  ReadBlockInfoBlock(bool ReadBlockInfoNames = false);
+
+  /// Set the block info to be used by this BitstreamCursor to interpret
+  /// abbreviated records.
+  void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
+};
+
+} // end llvm namespace
+
+#endif // LLVM_BITSTREAM_BITSTREAMREADER_H

llvm/trunk/include/llvm/Bitstream/BitstreamWriter.h

+//===- 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/Optional.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Bitstream/BitCodes.h"
+#include "llvm/Support/Endian.h"
+#include <vector>
+
+namespace llvm {
+
+class BitstreamWriter {
+  SmallVectorImpl<char> &Out;
+
+  /// 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 WriteByte(unsigned char Value) {
+    Out.push_back(Value);
+  }
+
+  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));
+  }
+
+  size_t GetBufferOffset() const { return Out.size(); }
+
+  size_t GetWordIndex() const {
+    size_t Offset = GetBufferOffset();
+    assert((Offset & 3) == 0 && "Not 32-bit aligned");
+    return Offset / 4;
+  }
+
+public:
+  explicit BitstreamWriter(SmallVectorImpl<char> &O)
+    : Out(O), 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;
+    unsigned ByteNo = BitNo / 8;
+    assert((!endian::readAtBitAlignment<uint32_t, little, unaligned>(
+               &Out[ByteNo], BitNo & 7)) &&
+           "Expected to be patching over 0-value placeholders");
+    endian::writeAtBitAlignment<uint32_t, little, unaligned>(
+        &Out[ByteNo], NewWord, BitNo & 7);
+  }
+
+  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 (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
+         i != e; ++i)
+      if (BlockInfoRecords[i].BlockID == BlockID)
+        return &BlockInfoRecords[i];
+    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)) {
+      CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
+                        Info->Abbrevs.end());
+    }
+  }
+
+  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();
+  }
+
+  //===--------------------------------------------------------------------===//
+  // 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, 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.getValue());
+      else {
+        assert(Op.getEncoding() != BitCodeAbbrevOp::Array &&
+               Op.getEncoding() != BitCodeAbbrevOp::Blob &&
+               "Expected literal or scalar");
+        EmitAbbreviatedField(Op, Code.getValue());
+      }
+    }
+
+    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.
+    for (const auto &B : Bytes) {
+      assert(isUInt<8>(B) && "Value too large to emit as byte");
+      WriteByte((unsigned char)B);
+    }
+
+    // Align end to 32-bits.
+    while (GetBufferOffset() & 3)
+      WriteByte(0);
+  }
+  void emitBlob(StringRef Bytes, bool ShouldEmitSize = true) {
+    emitBlob(makeArrayRef((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>(makeArrayRef(Vals).size());
+      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, makeArrayRef(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, makeArrayRef(Vals), StringRef(), None);
+  }
+
+  /// 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, makeArrayRef(Vals), Blob, None);
+  }
+  template <typename Container>
+  void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals,
+                          const char *BlobData, unsigned BlobLen) {
+    return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
+                                    StringRef(BlobData, BlobLen), None);
+  }
+
+  /// 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, makeArrayRef(Vals), Array, None);
+  }
+  template <typename Container>
+  void EmitRecordWithArray(unsigned Abbrev, const Container &Vals,
+                           const char *ArrayData, unsigned ArrayLen) {
+    return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
+                                    StringRef(ArrayData, ArrayLen), None);
+  }
+
+  //===--------------------------------------------------------------------===//
+  // 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

llvm/trunk/include/llvm/Support/JSON.h

 ///   complex format and data model, and YAML parsers aren't ubiquitous.
 ///   YAMLParser.h is a streaming parser suitable for parsing large documents
 ///   (including JSON, as YAML is a superset). It can be awkward to use
 ///   directly. YAML I/O (YAMLTraits.h) provides data mapping that is more
 ///   declarative than the toJSON/fromJSON conventions here.
 ///
 /// - LLVM bitstream is a space- and CPU- efficient binary format. Typically it
 ///   encodes LLVM IR ("bitcode"), but it can be a container for other data.
-///   Low-level reader/writer libraries are in Bitcode/Bitstream*.h
+///   Low-level reader/writer libraries are in Bitstream/Bitstream*.h
 ///
 //===---------------------------------------------------------------------===//
 
 #ifndef LLVM_SUPPORT_JSON_H
 #define LLVM_SUPPORT_JSON_H
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"

llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp

 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Bitcode/LLVMBitCodes.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/IR/Argument.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/CallingConv.h"

llvm/trunk/lib/Bitcode/Reader/BitstreamReader.cpp

-//===- BitstreamReader.cpp - BitstreamReader implementation ---------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Bitcode/BitstreamReader.h"
-#include "llvm/ADT/StringRef.h"
-#include <cassert>
-#include <string>
-
-using namespace llvm;
-
-//===----------------------------------------------------------------------===//
-//  BitstreamCursor implementation
-//===----------------------------------------------------------------------===//
-
-/// Having read the ENTER_SUBBLOCK abbrevid, enter the block.
-Error 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.
-  Expected<uint32_t> MaybeVBR = ReadVBR(bitc::CodeLenWidth);
-  if (!MaybeVBR)
-    return MaybeVBR.takeError();
-  CurCodeSize = MaybeVBR.get();
-
-  if (CurCodeSize > MaxChunkSize)
-    return llvm::createStringError(
-        std::errc::illegal_byte_sequence,
-        "can't read more than %zu at a time, trying to read %u", +MaxChunkSize,
-        CurCodeSize);
-
-  SkipToFourByteBoundary();
-  Expected<word_t> MaybeNum = Read(bitc::BlockSizeWidth);
-  if (!MaybeNum)
-    return MaybeNum.takeError();
-  word_t NumWords = MaybeNum.get();
-  if (NumWordsP)
-    *NumWordsP = NumWords;
-
-  if (CurCodeSize == 0)
-    return llvm::createStringError(
-        std::errc::illegal_byte_sequence,
-        "can't enter sub-block: current code size is 0");
-  if (AtEndOfStream())
-    return llvm::createStringError(
-        std::errc::illegal_byte_sequence,
-        "can't enter sub block: already at end of stream");
-
-  return Error::success();
-}
-
-static Expected<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:
-    if (Expected<unsigned> Res = Cursor.Read(6))
-      return BitCodeAbbrevOp::DecodeChar6(Res.get());
-    else
-      return Res.takeError();
-  }
-  llvm_unreachable("invalid abbreviation encoding");
-}
-
-static Error 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);
-    if (Expected<unsigned> Res = Cursor.Read((unsigned)Op.getEncodingData()))
-      break;
-    else
-      return Res.takeError();
-  case BitCodeAbbrevOp::VBR:
-    assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
-    if (Expected<uint64_t> Res =
-            Cursor.ReadVBR64((unsigned)Op.getEncodingData()))
-      break;
-    else
-      return Res.takeError();
-  case BitCodeAbbrevOp::Char6:
-    if (Expected<unsigned> Res = Cursor.Read(6))
-      break;
-    else
-      return Res.takeError();
-  }
-  return ErrorSuccess();
-}
-
-/// skipRecord - Read the current record and discard it.
-Expected<unsigned> BitstreamCursor::skipRecord(unsigned AbbrevID) {
-  // Skip unabbreviated records by reading past their entries.
-  if (AbbrevID == bitc::UNABBREV_RECORD) {
-    Expected<uint32_t> MaybeCode = ReadVBR(6);
-    if (!MaybeCode)
-      return MaybeCode.takeError();
-    unsigned Code = MaybeCode.get();
-    Expected<uint32_t> MaybeVBR = ReadVBR(6);
-    if (!MaybeVBR)
-      return MaybeVBR.get();
-    unsigned NumElts = MaybeVBR.get();
-    for (unsigned i = 0; i != NumElts; ++i)
-      if (Expected<uint64_t> Res = ReadVBR64(6))
-        ; // Skip!
-      else
-        return Res.takeError();
-    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)
-      return llvm::createStringError(
-          std::errc::illegal_byte_sequence,
-          "Abbreviation starts with an Array or a Blob");
-    Expected<uint64_t> MaybeCode = readAbbreviatedField(*this, CodeOp);
-    if (!MaybeCode)
-      return MaybeCode.takeError();
-    Code = MaybeCode.get();
-  }
-
-  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) {
-      if (Error Err = skipAbbreviatedField(*this, Op))
-        return std::move(Err);
-      continue;
-    }
-
-    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
-      // Array case.  Read the number of elements as a vbr6.
-      Expected<uint32_t> MaybeNum = ReadVBR(6);
-      if (!MaybeNum)
-        return MaybeNum.takeError();
-      unsigned NumElts = MaybeNum.get();
-
-      // 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);
-        if (Error Err = JumpToBit(GetCurrentBitNo() +
-                                  NumElts * EltEnc.getEncodingData()))
-          return std::move(Err);
-        break;
-      case BitCodeAbbrevOp::VBR:
-        assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
-        for (; NumElts; --NumElts)
-          if (Expected<uint64_t> Res =
-                  ReadVBR64((unsigned)EltEnc.getEncodingData()))
-            ; // Skip!
-          else
-            return Res.takeError();
-        break;
-      case BitCodeAbbrevOp::Char6:
-        if (Error Err = JumpToBit(GetCurrentBitNo() + NumElts * 6))
-          return std::move(Err);
-        break;
-      }
-      continue;
-    }
-
-    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
-    // Blob case.  Read the number of bytes as a vbr6.
-    Expected<uint32_t> MaybeNum = ReadVBR(6);
-    if (!MaybeNum)
-      return MaybeNum.takeError();
-    unsigned NumElts = MaybeNum.get();
-    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.
-    if (Error Err = JumpToBit(NewEnd))
-      return std::move(Err);
-  }
-  return Code;
-}
-
-Expected<unsigned> BitstreamCursor::readRecord(unsigned AbbrevID,
-                                               SmallVectorImpl<uint64_t> &Vals,
-                                               StringRef *Blob) {
-  if (AbbrevID == bitc::UNABBREV_RECORD) {
-    Expected<uint32_t> MaybeCode = ReadVBR(6);
-    if (!MaybeCode)
-      return MaybeCode.takeError();
-    uint32_t Code = MaybeCode.get();
-    Expected<uint32_t> MaybeNumElts = ReadVBR(6);
-    if (!MaybeNumElts)
-      return MaybeNumElts.takeError();
-    uint32_t NumElts = MaybeNumElts.get();
-
-    for (unsigned i = 0; i != NumElts; ++i)
-      if (Expected<uint64_t> MaybeVal = ReadVBR64(6))
-        Vals.push_back(MaybeVal.get());
-      else
-        return MaybeVal.takeError();
-    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");
-    if (Expected<uint64_t> MaybeCode = readAbbreviatedField(*this, CodeOp))
-      Code = MaybeCode.get();
-    else
-      return MaybeCode.takeError();
-  }
-
-  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) {
-      if (Expected<uint64_t> MaybeVal = readAbbreviatedField(*this, Op))
-        Vals.push_back(MaybeVal.get());
-      else
-        return MaybeVal.takeError();
-      continue;
-    }
-
-    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
-      // Array case.  Read the number of elements as a vbr6.
-      Expected<uint32_t> MaybeNumElts = ReadVBR(6);
-      if (!MaybeNumElts)
-        return MaybeNumElts.takeError();
-      uint32_t NumElts = MaybeNumElts.get();
-
-      // 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)
-          if (Expected<SimpleBitstreamCursor::word_t> MaybeVal =
-                  Read((unsigned)EltEnc.getEncodingData()))
-            Vals.push_back(MaybeVal.get());
-          else
-            return MaybeVal.takeError();
-        break;
-      case BitCodeAbbrevOp::VBR:
-        for (; NumElts; --NumElts)
-          if (Expected<uint64_t> MaybeVal =
-                  ReadVBR64((unsigned)EltEnc.getEncodingData()))
-            Vals.push_back(MaybeVal.get());
-          else
-            return MaybeVal.takeError();
-        break;
-      case BitCodeAbbrevOp::Char6:
-        for (; NumElts; --NumElts)
-          if (Expected<SimpleBitstreamCursor::word_t> MaybeVal = Read(6))
-            Vals.push_back(BitCodeAbbrevOp::DecodeChar6(MaybeVal.get()));
-          else
-            return MaybeVal.takeError();
-      }
-      continue;
-    }
-
-    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
-    // Blob case.  Read the number of bytes as a vbr6.
-    Expected<uint32_t> MaybeNumElts = ReadVBR(6);
-    if (!MaybeNumElts)
-      return MaybeNumElts.takeError();
-    uint32_t NumElts = MaybeNumElts.get();
-    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.
-    if (Error Err = JumpToBit(NewEnd))
-      return std::move(Err);
-    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;
-}
-
-Error BitstreamCursor::ReadAbbrevRecord() {
-  auto Abbv = std::make_shared<BitCodeAbbrev>();
-  Expected<uint32_t> MaybeNumOpInfo = ReadVBR(5);
-  if (!MaybeNumOpInfo)
-    return MaybeNumOpInfo.takeError();
-  unsigned NumOpInfo = MaybeNumOpInfo.get();
-  for (unsigned i = 0; i != NumOpInfo; ++i) {
-    Expected<word_t> MaybeIsLiteral = Read(1);
-    if (!MaybeIsLiteral)
-      return MaybeIsLiteral.takeError();
-    bool IsLiteral = MaybeIsLiteral.get();
-    if (IsLiteral) {
-      Expected<uint64_t> MaybeOp = ReadVBR64(8);
-      if (!MaybeOp)
-        return MaybeOp.takeError();
-      Abbv->Add(BitCodeAbbrevOp(MaybeOp.get()));
-      continue;
-    }
-
-    Expected<word_t> MaybeEncoding = Read(3);
-    if (!MaybeEncoding)
-      return MaybeEncoding.takeError();
-    BitCodeAbbrevOp::Encoding E =
-        (BitCodeAbbrevOp::Encoding)MaybeEncoding.get();
-    if (BitCodeAbbrevOp::hasEncodingData(E)) {
-      Expected<uint64_t> MaybeData = ReadVBR64(5);
-      if (!MaybeData)
-        return MaybeData.takeError();
-      uint64_t Data = MaybeData.get();
-
-      // 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));
-
-  return Error::success();
-}
-
-Expected<Optional<BitstreamBlockInfo>>
-BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
-  if (llvm::Error Err = EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID))
-    return std::move(Err);
-
-  BitstreamBlockInfo NewBlockInfo;
-
-  SmallVector<uint64_t, 64> Record;
-  BitstreamBlockInfo::BlockInfo *CurBlockInfo = nullptr;
-
-  // Read all the records for this module.
-  while (true) {
-    Expected<BitstreamEntry> MaybeEntry =
-        advanceSkippingSubblocks(AF_DontAutoprocessAbbrevs);
-    if (!MaybeEntry)
-      return MaybeEntry.takeError();
-    BitstreamEntry Entry = MaybeEntry.get();
-
-    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;
-      if (Error Err = ReadAbbrevRecord())
-        return std::move(Err);
-
-      // 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();
-    Expected<unsigned> MaybeBlockInfo = readRecord(Entry.ID, Record);
-    if (!MaybeBlockInfo)
-      return MaybeBlockInfo.takeError();
-    switch (MaybeBlockInfo.get()) {
-    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;
-      }
-      }
-  }
-}

llvm/trunk/lib/Bitcode/Reader/CMakeLists.txt

 add_llvm_library(LLVMBitReader
   BitReader.cpp
   BitcodeReader.cpp
-  BitstreamReader.cpp
   MetadataLoader.cpp
   ValueList.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Bitcode
 
   DEPENDS
   intrinsics_gen
   )

llvm/trunk/lib/Bitcode/Reader/LLVMBuild.txt

 ;   http://llvm.org/docs/LLVMBuild.html
 ;
 ;===------------------------------------------------------------------------===;
 
 [component_0]
 type = Library
 name = BitReader
 parent = Bitcode
-required_libraries = Core Support
+required_libraries = BitstreamReader Core Support

llvm/trunk/lib/Bitcode/Reader/MetadataLoader.cpp

 #include "llvm/ADT/None.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Bitcode/BitcodeReader.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Bitcode/LLVMBitCodes.h"
 #include "llvm/IR/Argument.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/IR/Constant.h"

llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp

 #include "llvm/ADT/None.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
-#include "llvm/Bitcode/BitCodes.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitstream/BitCodes.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Bitcode/LLVMBitCodes.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"

llvm/trunk/lib/Bitstream/CMakeLists.txt

+add_subdirectory(Reader)
+# The writer is header-only.

llvm/trunk/lib/Bitstream/LLVMBuild.txt

+;===- ./lib/Bitstream/LLVMBuild.txt ----------------------------*- Conf -*--===;
+;
+; 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 is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[common]
+subdirectories = Reader
+
+[component_0]
+type = Group
+name = Bitstream
+parent = Libraries

llvm/trunk/lib/Bitstream/Reader/BitstreamReader.cpp

+//===- BitstreamReader.cpp - BitstreamReader implementation ---------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitstream/BitstreamReader.h"
+#include "llvm/ADT/StringRef.h"
+#include <cassert>
+#include <string>
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//  BitstreamCursor implementation
+//===----------------------------------------------------------------------===//
+
+/// Having read the ENTER_SUBBLOCK abbrevid, enter the block.
+Error 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.
+  Expected<uint32_t> MaybeVBR = ReadVBR(bitc::CodeLenWidth);
+  if (!MaybeVBR)
+    return MaybeVBR.takeError();
+  CurCodeSize = MaybeVBR.get();
+
+  if (CurCodeSize > MaxChunkSize)
+    return llvm::createStringError(
+        std::errc::illegal_byte_sequence,
+        "can't read more than %zu at a time, trying to read %u", +MaxChunkSize,
+        CurCodeSize);
+
+  SkipToFourByteBoundary();
+  Expected<word_t> MaybeNum = Read(bitc::BlockSizeWidth);
+  if (!MaybeNum)
+    return MaybeNum.takeError();
+  word_t NumWords = MaybeNum.get();
+  if (NumWordsP)
+    *NumWordsP = NumWords;
+
+  if (CurCodeSize == 0)
+    return llvm::createStringError(
+        std::errc::illegal_byte_sequence,
+        "can't enter sub-block: current code size is 0");
+  if (AtEndOfStream())
+    return llvm::createStringError(
+        std::errc::illegal_byte_sequence,
+        "can't enter sub block: already at end of stream");
+
+  return Error::success();
+}
+
+static Expected<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:
+    if (Expected<unsigned> Res = Cursor.Read(6))
+      return BitCodeAbbrevOp::DecodeChar6(Res.get());
+    else
+      return Res.takeError();
+  }
+  llvm_unreachable("invalid abbreviation encoding");
+}
+
+static Error 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);
+    if (Expected<unsigned> Res = Cursor.Read((unsigned)Op.getEncodingData()))
+      break;
+    else
+      return Res.takeError();
+  case BitCodeAbbrevOp::VBR:
+    assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
+    if (Expected<uint64_t> Res =
+            Cursor.ReadVBR64((unsigned)Op.getEncodingData()))
+      break;
+    else
+      return Res.takeError();
+  case BitCodeAbbrevOp::Char6:
+    if (Expected<unsigned> Res = Cursor.Read(6))
+      break;
+    else
+      return Res.takeError();
+  }
+  return ErrorSuccess();
+}
+
+/// skipRecord - Read the current record and discard it.
+Expected<unsigned> BitstreamCursor::skipRecord(unsigned AbbrevID) {
+  // Skip unabbreviated records by reading past their entries.
+  if (AbbrevID == bitc::UNABBREV_RECORD) {
+    Expected<uint32_t> MaybeCode = ReadVBR(6);
+    if (!MaybeCode)
+      return MaybeCode.takeError();
+    unsigned Code = MaybeCode.get();
+    Expected<uint32_t> MaybeVBR = ReadVBR(6);
+    if (!MaybeVBR)
+      return MaybeVBR.get();
+    unsigned NumElts = MaybeVBR.get();
+    for (unsigned i = 0; i != NumElts; ++i)
+      if (Expected<uint64_t> Res = ReadVBR64(6))
+        ; // Skip!
+      else
+        return Res.takeError();
+    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)
+      return llvm::createStringError(
+          std::errc::illegal_byte_sequence,
+          "Abbreviation starts with an Array or a Blob");
+    Expected<uint64_t> MaybeCode = readAbbreviatedField(*this, CodeOp);
+    if (!MaybeCode)
+      return MaybeCode.takeError();
+    Code = MaybeCode.get();
+  }
+
+  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) {
+      if (Error Err = skipAbbreviatedField(*this, Op))
+        return std::move(Err);
+      continue;
+    }
+
+    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+      // Array case.  Read the number of elements as a vbr6.
+      Expected<uint32_t> MaybeNum = ReadVBR(6);
+      if (!MaybeNum)
+        return MaybeNum.takeError();
+      unsigned NumElts = MaybeNum.get();
+
+      // 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);
+        if (Error Err = JumpToBit(GetCurrentBitNo() +
+                                  NumElts * EltEnc.getEncodingData()))
+          return std::move(Err);
+        break;
+      case BitCodeAbbrevOp::VBR:
+        assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
+        for (; NumElts; --NumElts)
+          if (Expected<uint64_t> Res =
+                  ReadVBR64((unsigned)EltEnc.getEncodingData()))
+            ; // Skip!
+          else
+            return Res.takeError();
+        break;
+      case BitCodeAbbrevOp::Char6:
+        if (Error Err = JumpToBit(GetCurrentBitNo() + NumElts * 6))
+          return std::move(Err);
+        break;
+      }
+      continue;
+    }
+
+    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
+    // Blob case.  Read the number of bytes as a vbr6.
+    Expected<uint32_t> MaybeNum = ReadVBR(6);
+    if (!MaybeNum)
+      return MaybeNum.takeError();
+    unsigned NumElts = MaybeNum.get();
+    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.
+    if (Error Err = JumpToBit(NewEnd))
+      return std::move(Err);
+  }
+  return Code;
+}
+
+Expected<unsigned> BitstreamCursor::readRecord(unsigned AbbrevID,
+                                               SmallVectorImpl<uint64_t> &Vals,
+                                               StringRef *Blob) {
+  if (AbbrevID == bitc::UNABBREV_RECORD) {
+    Expected<uint32_t> MaybeCode = ReadVBR(6);
+    if (!MaybeCode)
+      return MaybeCode.takeError();
+    uint32_t Code = MaybeCode.get();
+    Expected<uint32_t> MaybeNumElts = ReadVBR(6);
+    if (!MaybeNumElts)
+      return MaybeNumElts.takeError();
+    uint32_t NumElts = MaybeNumElts.get();
+
+    for (unsigned i = 0; i != NumElts; ++i)
+      if (Expected<uint64_t> MaybeVal = ReadVBR64(6))
+        Vals.push_back(MaybeVal.get());
+      else
+        return MaybeVal.takeError();
+    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");
+    if (Expected<uint64_t> MaybeCode = readAbbreviatedField(*this, CodeOp))
+      Code = MaybeCode.get();
+    else
+      return MaybeCode.takeError();
+  }
+
+  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) {
+      if (Expected<uint64_t> MaybeVal = readAbbreviatedField(*this, Op))
+        Vals.push_back(MaybeVal.get());
+      else
+        return MaybeVal.takeError();
+      continue;
+    }
+
+    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+      // Array case.  Read the number of elements as a vbr6.
+      Expected<uint32_t> MaybeNumElts = ReadVBR(6);
+      if (!MaybeNumElts)
+        return MaybeNumElts.takeError();
+      uint32_t NumElts = MaybeNumElts.get();
+
+      // 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)
+          if (Expected<SimpleBitstreamCursor::word_t> MaybeVal =
+                  Read((unsigned)EltEnc.getEncodingData()))
+            Vals.push_back(MaybeVal.get());
+          else
+            return MaybeVal.takeError();
+        break;
+      case BitCodeAbbrevOp::VBR:
+        for (; NumElts; --NumElts)
+          if (Expected<uint64_t> MaybeVal =
+                  ReadVBR64((unsigned)EltEnc.getEncodingData()))
+            Vals.push_back(MaybeVal.get());
+          else
+            return MaybeVal.takeError();
+        break;
+      case BitCodeAbbrevOp::Char6:
+        for (; NumElts; --NumElts)
+          if (Expected<SimpleBitstreamCursor::word_t> MaybeVal = Read(6))
+            Vals.push_back(BitCodeAbbrevOp::DecodeChar6(MaybeVal.get()));
+          else
+            return MaybeVal.takeError();
+      }
+      continue;
+    }
+
+    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
+    // Blob case.  Read the number of bytes as a vbr6.
+    Expected<uint32_t> MaybeNumElts = ReadVBR(6);
+    if (!MaybeNumElts)
+      return MaybeNumElts.takeError();
+    uint32_t NumElts = MaybeNumElts.get();
+    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.
+    if (Error Err = JumpToBit(NewEnd))
+      return std::move(Err);
+    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;
+}
+
+Error BitstreamCursor::ReadAbbrevRecord() {
+  auto Abbv = std::make_shared<BitCodeAbbrev>();
+  Expected<uint32_t> MaybeNumOpInfo = ReadVBR(5);
+  if (!MaybeNumOpInfo)
+    return MaybeNumOpInfo.takeError();
+  unsigned NumOpInfo = MaybeNumOpInfo.get();
+  for (unsigned i = 0; i != NumOpInfo; ++i) {
+    Expected<word_t> MaybeIsLiteral = Read(1);
+    if (!MaybeIsLiteral)
+      return MaybeIsLiteral.takeError();
+    bool IsLiteral = MaybeIsLiteral.get();
+    if (IsLiteral) {
+      Expected<uint64_t> MaybeOp = ReadVBR64(8);
+      if (!MaybeOp)
+        return MaybeOp.takeError();
+      Abbv->Add(BitCodeAbbrevOp(MaybeOp.get()));
+      continue;
+    }
+
+    Expected<word_t> MaybeEncoding = Read(3);
+    if (!MaybeEncoding)
+      return MaybeEncoding.takeError();
+    BitCodeAbbrevOp::Encoding E =
+        (BitCodeAbbrevOp::Encoding)MaybeEncoding.get();
+    if (BitCodeAbbrevOp::hasEncodingData(E)) {
+      Expected<uint64_t> MaybeData = ReadVBR64(5);
+      if (!MaybeData)
+        return MaybeData.takeError();
+      uint64_t Data = MaybeData.get();
+
+      // 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));
+
+  return Error::success();
+}
+
+Expected<Optional<BitstreamBlockInfo>>
+BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
+  if (llvm::Error Err = EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID))
+    return std::move(Err);
+
+  BitstreamBlockInfo NewBlockInfo;
+
+  SmallVector<uint64_t, 64> Record;
+  BitstreamBlockInfo::BlockInfo *CurBlockInfo = nullptr;
+
+  // Read all the records for this module.
+  while (true) {
+    Expected<BitstreamEntry> MaybeEntry =
+        advanceSkippingSubblocks(AF_DontAutoprocessAbbrevs);
+    if (!MaybeEntry)
+      return MaybeEntry.takeError();
+    BitstreamEntry Entry = MaybeEntry.get();
+
+    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;
+      if (Error Err = ReadAbbrevRecord())
+        return std::move(Err);
+
+      // 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();
+    Expected<unsigned> MaybeBlockInfo = readRecord(Entry.ID, Record);
+    if (!MaybeBlockInfo)
+      return MaybeBlockInfo.takeError();
+    switch (MaybeBlockInfo.get()) {
+    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;
+      }
+      }
+  }
+}

llvm/trunk/lib/Bitstream/Reader/CMakeLists.txt

+add_llvm_library(LLVMBitstreamReader
+  BitstreamReader.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/Bitcode
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/Bitstream
+  )

llvm/trunk/lib/Bitstream/Reader/LLVMBuild.txt

+;===- ./lib/Bitstream/Reader/LLVMBuild.txt ---------------------*- Conf -*--===;
+;
+; 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 is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = BitstreamReader
+parent = Bitstream
+required_libraries = Support

llvm/trunk/lib/CMakeLists.txt

 # `Demangle', `Support' and `TableGen' libraries are added on the top-level
 # CMakeLists.txt
 
 add_subdirectory(IR)
 add_subdirectory(FuzzMutate)
 add_subdirectory(IRReader)
 add_subdirectory(CodeGen)
 add_subdirectory(BinaryFormat)
 add_subdirectory(Bitcode)
+add_subdirectory(Bitstream)
 add_subdirectory(Transforms)
 add_subdirectory(Linker)
 add_subdirectory(Analysis)
 add_subdirectory(LTO)
 add_subdirectory(MC)
 add_subdirectory(MCA)
 add_subdirectory(Object)
 add_subdirectory(ObjectYAML)

llvm/trunk/lib/LLVMBuild.txt

 ;
 ;===------------------------------------------------------------------------===;
 
 [common]
 subdirectories =
  Analysis
  AsmParser
  Bitcode
+ Bitstream
  CodeGen
  DebugInfo
  Demangle
  ExecutionEngine
  FuzzMutate
  LineEditor
  Linker
  IR

llvm/trunk/tools/llvm-bcanalyzer/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   BitReader
+  BitstreamReader
   Support
   )
 
 add_llvm_tool(llvm-bcanalyzer
   llvm-bcanalyzer.cpp
 
   DEPENDS
   intrinsics_gen
   )

llvm/trunk/tools/llvm-bcanalyzer/LLVMBuild.txt

 ;   http://llvm.org/docs/LLVMBuild.html
 ;
 ;===------------------------------------------------------------------------===;
 
 [component_0]
 type = Tool
 name = llvm-bcanalyzer
 parent = Tools
-required_libraries = BitReader
+required_libraries = BitReader BitstreamReader Support

llvm/trunk/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp

 // The tool is also able to print a bitcode file in a straight forward text
 // format that shows the containment and relationships of the information in
 // the bitcode file (-dump option).
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Bitcode/BitcodeReader.h"
-#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Bitcode/LLVMBitCodes.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/SHA1.h"
 #include "llvm/Support/WithColor.h"

llvm/trunk/unittests/Bitcode/BitstreamReaderTest.cpp

-//===- BitstreamReaderTest.cpp - Tests for BitstreamReader ----------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Bitcode/BitstreamReader.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
-#include "gtest/gtest.h"
-
-using namespace llvm;
-
-namespace {
-
-TEST(BitstreamReaderTest, AtEndOfStream) {
-  uint8_t Bytes[4] = {
-    0x00, 0x01, 0x02, 0x03
-  };
-  BitstreamCursor Cursor(Bytes);
-
-  EXPECT_FALSE(Cursor.AtEndOfStream());
-  Expected<SimpleBitstreamCursor::word_t> MaybeRead = Cursor.Read(8);
-  EXPECT_TRUE((bool)MaybeRead);
-  EXPECT_FALSE(Cursor.AtEndOfStream());
-  MaybeRead = Cursor.Read(24);
-  EXPECT_TRUE((bool)MaybeRead);
-  EXPECT_TRUE(Cursor.AtEndOfStream());
-
-  EXPECT_FALSE(Cursor.JumpToBit(0));
-  EXPECT_FALSE(Cursor.AtEndOfStream());
-
-  EXPECT_FALSE(Cursor.JumpToBit(32));
-  EXPECT_TRUE(Cursor.AtEndOfStream());
-}
-
-TEST(BitstreamReaderTest, AtEndOfStreamJump) {
-  uint8_t Bytes[4] = {
-    0x00, 0x01, 0x02, 0x03
-  };
-  BitstreamCursor Cursor(Bytes);
-
-  EXPECT_FALSE(Cursor.JumpToBit(32));
-  EXPECT_TRUE(Cursor.AtEndOfStream());
-}
-
-TEST(BitstreamReaderTest, AtEndOfStreamEmpty) {
-  BitstreamCursor Cursor(ArrayRef<uint8_t>{});
-
-  EXPECT_TRUE(Cursor.AtEndOfStream());
-}
-
-TEST(BitstreamReaderTest, getCurrentByteNo) {
-  uint8_t Bytes[] = {0x00, 0x01, 0x02, 0x03};
-  SimpleBitstreamCursor Cursor(Bytes);
-
-  for (unsigned I = 0, E = 32; I != E; ++I) {
-    EXPECT_EQ(I / 8, Cursor.getCurrentByteNo());
-    Expected<SimpleBitstreamCursor::word_t> MaybeRead = Cursor.Read(1);
-    EXPECT_TRUE((bool)MaybeRead);
-  }
-  EXPECT_EQ(4u, Cursor.getCurrentByteNo());
-}
-
-TEST(BitstreamReaderTest, getPointerToByte) {
-  uint8_t Bytes[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
-  SimpleBitstreamCursor Cursor(Bytes);
-
-  for (unsigned I = 0, E = 8; I != E; ++I) {
-    EXPECT_EQ(Bytes + I, Cursor.getPointerToByte(I, 1));
-  }
-}
-
-TEST(BitstreamReaderTest, getPointerToBit) {
-  uint8_t Bytes[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
-  SimpleBitstreamCursor Cursor(Bytes);
-
-  for (unsigned I = 0, E = 8; I != E; ++I) {
-    EXPECT_EQ(Bytes + I, Cursor.getPointerToBit(I * 8, 1));
-  }
-}
-
-TEST(BitstreamReaderTest, readRecordWithBlobWhileStreaming) {
-  SmallVector<uint8_t, 1> BlobData;
-  for (unsigned I = 0, E = 1024; I != E; ++I)
-    BlobData.push_back(I);
-
-  // Try a bunch of different sizes.
-  const unsigned Magic = 0x12345678;
-  const unsigned BlockID = bitc::FIRST_APPLICATION_BLOCKID;
-  const unsigned RecordID = 1;
-  for (unsigned I = 0, BlobSize = 0, E = BlobData.size(); BlobSize < E;
-       BlobSize += ++I) {
-    StringRef BlobIn((const char *)BlobData.begin(), BlobSize);
-
-    // Write the bitcode.
-    SmallVector<char, 1> Buffer;
-    unsigned AbbrevID;
-    {
-      BitstreamWriter Stream(Buffer);
-      Stream.Emit(Magic, 32);
-      Stream.EnterSubblock(BlockID, 3);
-
-      auto Abbrev = std::make_shared<BitCodeAbbrev>();
-      Abbrev->Add(BitCodeAbbrevOp(RecordID));
-      Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
-      AbbrevID = Stream.EmitAbbrev(std::move(Abbrev));
-      unsigned Record[] = {RecordID};
-      Stream.EmitRecordWithBlob(AbbrevID, makeArrayRef(Record), BlobIn);
-
-      Stream.ExitBlock();
-    }
-
-    // Stream the buffer into the reader.
-    BitstreamCursor Stream(
-        ArrayRef<uint8_t>((const uint8_t *)Buffer.begin(), Buffer.size()));
-
-    // Header.  Included in test so that we can run llvm-bcanalyzer to debug
-    // when there are problems.
-    Expected<SimpleBitstreamCursor::word_t> MaybeRead = Stream.Read(32);
-    ASSERT_TRUE((bool)MaybeRead);
-    ASSERT_EQ(Magic, MaybeRead.get());
-
-    // Block.
-    Expected<BitstreamEntry> MaybeEntry =
-        Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
-    ASSERT_TRUE((bool)MaybeEntry);
-    BitstreamEntry Entry = MaybeEntry.get();
-    ASSERT_EQ(BitstreamEntry::SubBlock, Entry.Kind);
-    ASSERT_EQ(BlockID, Entry.ID);
-    ASSERT_FALSE(Stream.EnterSubBlock(BlockID));
-
-    // Abbreviation.
-    MaybeEntry = Stream.advance();
-    ASSERT_TRUE((bool)MaybeEntry);
-    Entry = MaybeEntry.get();
-    ASSERT_EQ(BitstreamEntry::Record, Entry.Kind);
-    ASSERT_EQ(AbbrevID, Entry.ID);
-
-    // Record.
-    StringRef BlobOut;
-    SmallVector<uint64_t, 1> Record;
-    Expected<unsigned> MaybeRecord =
-        Stream.readRecord(Entry.ID, Record, &BlobOut);
-    ASSERT_TRUE((bool)MaybeRecord);
-    ASSERT_EQ(RecordID, MaybeRecord.get());
-    EXPECT_TRUE(Record.empty());
-    EXPECT_EQ(BlobIn, BlobOut);
-  }
-}
-
-TEST(BitstreamReaderTest, shortRead) {
-  uint8_t Bytes[] = {8, 7, 6, 5, 4, 3, 2, 1};
-  for (unsigned I = 1; I != 8; ++I) {
-    SimpleBitstreamCursor Cursor(ArrayRef<uint8_t>(Bytes, I));
-    Expected<SimpleBitstreamCursor::word_t> MaybeRead = Cursor.Read(8);
-    ASSERT_TRUE((bool)MaybeRead);
-    EXPECT_EQ(8ull, MaybeRead.get());
-  }
-}
-
-static_assert(is_trivially_copyable<BitCodeAbbrevOp>::value,
-              "trivially copyable");
-
-} // end anonymous namespace

llvm/trunk/unittests/Bitcode/BitstreamWriterTest.cpp

-//===- BitstreamWriterTest.cpp - Tests for BitstreamWriter ----------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Bitcode/BitstreamWriter.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallString.h"
-#include "gtest/gtest.h"
-
-using namespace llvm;
-
-namespace {
-
-TEST(BitstreamWriterTest, emitBlob) {
-  SmallString<64> Buffer;
-  BitstreamWriter W(Buffer);
-  W.emitBlob("str", /* ShouldEmitSize */ false);
-  EXPECT_EQ(StringRef("str\0", 4), Buffer);
-}
-
-TEST(BitstreamWriterTest, emitBlobWithSize) {
-  SmallString<64> Buffer;
-  {
-    BitstreamWriter W(Buffer);
-    W.emitBlob("str");
-  }
-  SmallString<64> Expected;
-  {
-    BitstreamWriter W(Expected);
-    W.EmitVBR(3, 6);
-    W.FlushToWord();
-    W.Emit('s', 8);
-    W.Emit('t', 8);
-    W.Emit('r', 8);
-    W.Emit(0, 8);
-  }
-  EXPECT_EQ(StringRef(Expected), Buffer);
-}
-
-TEST(BitstreamWriterTest, emitBlobEmpty) {
-  SmallString<64> Buffer;
-  BitstreamWriter W(Buffer);
-  W.emitBlob("", /* ShouldEmitSize */ false);
-  EXPECT_EQ(StringRef(""), Buffer);
-}
-
-TEST(BitstreamWriterTest, emitBlob4ByteAligned) {
-  SmallString<64> Buffer;
-  BitstreamWriter W(Buffer);
-  W.emitBlob("str0", /* ShouldEmitSize */ false);
-  EXPECT_EQ(StringRef("str0"), Buffer);
-}
-
-} // end namespace

llvm/trunk/unittests/Bitcode/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   AsmParser
   BitReader
   BitWriter
   Core
   Support
   )
 
 add_llvm_unittest(BitcodeTests
   BitReaderTest.cpp
-  BitstreamReaderTest.cpp
-  BitstreamWriterTest.cpp
   )

llvm/trunk/unittests/Bitstream/BitstreamReaderTest.cpp

+//===- BitstreamReaderTest.cpp - Tests for BitstreamReader ----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitstream/BitstreamReader.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(BitstreamReaderTest, AtEndOfStream) {
+  uint8_t Bytes[4] = {
+    0x00, 0x01, 0x02, 0x03
+  };
+  BitstreamCursor Cursor(Bytes);
+
+  EXPECT_FALSE(Cursor.AtEndOfStream());
+  Expected<SimpleBitstreamCursor::word_t> MaybeRead = Cursor.Read(8);
+  EXPECT_TRUE((bool)MaybeRead);
+  EXPECT_FALSE(Cursor.AtEndOfStream());
+  MaybeRead = Cursor.Read(24);
+  EXPECT_TRUE((bool)MaybeRead);
+  EXPECT_TRUE(Cursor.AtEndOfStream());
+
+  EXPECT_FALSE(Cursor.JumpToBit(0));
+  EXPECT_FALSE(Cursor.AtEndOfStream());
+
+  EXPECT_FALSE(Cursor.JumpToBit(32));
+  EXPECT_TRUE(Cursor.AtEndOfStream());
+}
+
+TEST(BitstreamReaderTest, AtEndOfStreamJump) {
+  uint8_t Bytes[4] = {
+    0x00, 0x01, 0x02, 0x03
+  };
+  BitstreamCursor Cursor(Bytes);
+
+  EXPECT_FALSE(Cursor.JumpToBit(32));
+  EXPECT_TRUE(Cursor.AtEndOfStream());
+}
+
+TEST(BitstreamReaderTest, AtEndOfStreamEmpty) {
+  BitstreamCursor Cursor(ArrayRef<uint8_t>{});
+
+  EXPECT_TRUE(Cursor.AtEndOfStream());
+}
+
+TEST(BitstreamReaderTest, getCurrentByteNo) {
+  uint8_t Bytes[] = {0x00, 0x01, 0x02, 0x03};
+  SimpleBitstreamCursor Cursor(Bytes);
+
+  for (unsigned I = 0, E = 32; I != E; ++I) {
+    EXPECT_EQ(I / 8, Cursor.getCurrentByteNo());
+    Expected<SimpleBitstreamCursor::word_t> MaybeRead = Cursor.Read(1);
+    EXPECT_TRUE((bool)MaybeRead);
+  }
+  EXPECT_EQ(4u, Cursor.getCurrentByteNo());
+}
+
+TEST(BitstreamReaderTest, getPointerToByte) {
+  uint8_t Bytes[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
+  SimpleBitstreamCursor Cursor(Bytes);
+
+  for (unsigned I = 0, E = 8; I != E; ++I) {
+    EXPECT_EQ(Bytes + I, Cursor.getPointerToByte(I, 1));
+  }
+}
+
+TEST(BitstreamReaderTest, getPointerToBit) {
+  uint8_t Bytes[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
+  SimpleBitstreamCursor Cursor(Bytes);
+
+  for (unsigned I = 0, E = 8; I != E; ++I) {
+    EXPECT_EQ(Bytes + I, Cursor.getPointerToBit(I * 8, 1));
+  }
+}
+
+TEST(BitstreamReaderTest, readRecordWithBlobWhileStreaming) {
+  SmallVector<uint8_t, 1> BlobData;
+  for (unsigned I = 0, E = 1024; I != E; ++I)
+    BlobData.push_back(I);
+
+  // Try a bunch of different sizes.
+  const unsigned Magic = 0x12345678;
+  const unsigned BlockID = bitc::FIRST_APPLICATION_BLOCKID;
+  const unsigned RecordID = 1;
+  for (unsigned I = 0, BlobSize = 0, E = BlobData.size(); BlobSize < E;
+       BlobSize += ++I) {
+    StringRef BlobIn((const char *)BlobData.begin(), BlobSize);
+
+    // Write the bitcode.
+    SmallVector<char, 1> Buffer;
+    unsigned AbbrevID;
+    {
+      BitstreamWriter Stream(Buffer);
+      Stream.Emit(Magic, 32);
+      Stream.EnterSubblock(BlockID, 3);
+
+      auto Abbrev = std::make_shared<BitCodeAbbrev>();
+      Abbrev->Add(BitCodeAbbrevOp(RecordID));
+      Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
+      AbbrevID = Stream.EmitAbbrev(std::move(Abbrev));
+      unsigned Record[] = {RecordID};
+      Stream.EmitRecordWithBlob(AbbrevID, makeArrayRef(Record), BlobIn);
+
+      Stream.ExitBlock();
+    }
+
+    // Stream the buffer into the reader.
+    BitstreamCursor Stream(
+        ArrayRef<uint8_t>((const uint8_t *)Buffer.begin(), Buffer.size()));
+
+    // Header.  Included in test so that we can run llvm-bcanalyzer to debug
+    // when there are problems.
+    Expected<SimpleBitstreamCursor::word_t> MaybeRead = Stream.Read(32);
+    ASSERT_TRUE((bool)MaybeRead);
+    ASSERT_EQ(Magic, MaybeRead.get());
+
+    // Block.
+    Expected<BitstreamEntry> MaybeEntry =
+        Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
+    ASSERT_TRUE((bool)MaybeEntry);
+    BitstreamEntry Entry = MaybeEntry.get();
+    ASSERT_EQ(BitstreamEntry::SubBlock, Entry.Kind);
+    ASSERT_EQ(BlockID, Entry.ID);
+    ASSERT_FALSE(Stream.EnterSubBlock(BlockID));
+
+    // Abbreviation.
+    MaybeEntry = Stream.advance();
+    ASSERT_TRUE((bool)MaybeEntry);
+    Entry = MaybeEntry.get();
+    ASSERT_EQ(BitstreamEntry::Record, Entry.Kind);
+    ASSERT_EQ(AbbrevID, Entry.ID);
+
+    // Record.
+    StringRef BlobOut;
+    SmallVector<uint64_t, 1> Record;
+    Expected<unsigned> MaybeRecord =
+        Stream.readRecord(Entry.ID, Record, &BlobOut);
+    ASSERT_TRUE((bool)MaybeRecord);
+    ASSERT_EQ(RecordID, MaybeRecord.get());
+    EXPECT_TRUE(Record.empty());
+    EXPECT_EQ(BlobIn, BlobOut);
+  }
+}
+
+TEST(BitstreamReaderTest, shortRead) {
+  uint8_t Bytes[] = {8, 7, 6, 5, 4, 3, 2, 1};
+  for (unsigned I = 1; I != 8; ++I) {
+    SimpleBitstreamCursor Cursor(ArrayRef<uint8_t>(Bytes, I));
+    Expected<SimpleBitstreamCursor::word_t> MaybeRead = Cursor.Read(8);
+    ASSERT_TRUE((bool)MaybeRead);
+    EXPECT_EQ(8ull, MaybeRead.get());
+  }
+}
+
+static_assert(is_trivially_copyable<BitCodeAbbrevOp>::value,
+              "trivially copyable");
+
+} // end anonymous namespace

llvm/trunk/unittests/Bitstream/BitstreamWriterTest.cpp

+//===- BitstreamWriterTest.cpp - Tests for BitstreamWriter ----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitstream/BitstreamWriter.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(BitstreamWriterTest, emitBlob) {
+  SmallString<64> Buffer;
+  BitstreamWriter W(Buffer);
+  W.emitBlob("str", /* ShouldEmitSize */ false);
+  EXPECT_EQ(StringRef("str\0", 4), Buffer);
+}
+
+TEST(BitstreamWriterTest, emitBlobWithSize) {
+  SmallString<64> Buffer;
+  {
+    BitstreamWriter W(Buffer);
+    W.emitBlob("str");
+  }
+  SmallString<64> Expected;
+  {
+    BitstreamWriter W(Expected);
+    W.EmitVBR(3, 6);
+    W.FlushToWord();
+    W.Emit('s', 8);
+    W.Emit('t', 8);
+    W.Emit('r', 8);
+    W.Emit(0, 8);
+  }
+  EXPECT_EQ(StringRef(Expected), Buffer);
+}
+
+TEST(BitstreamWriterTest, emitBlobEmpty) {
+  SmallString<64> Buffer;
+  BitstreamWriter W(Buffer);
+  W.emitBlob("", /* ShouldEmitSize */ false);
+  EXPECT_EQ(StringRef(""), Buffer);
+}
+
+TEST(BitstreamWriterTest, emitBlob4ByteAligned) {
+  SmallString<64> Buffer;
+  BitstreamWriter W(Buffer);
+  W.emitBlob("str0", /* ShouldEmitSize */ false);
+  EXPECT_EQ(StringRef("str0"), Buffer);
+}
+
+} // end namespace

llvm/trunk/unittests/Bitstream/CMakeLists.txt

+set(LLVM_LINK_COMPONENTS
+  BitstreamReader
+  )
+
+add_llvm_unittest(BitstreamTests
+  BitstreamReaderTest.cpp
+  BitstreamWriterTest.cpp
+  )

llvm/trunk/unittests/CMakeLists.txt

 add_custom_target(UnitTests)
 set_target_properties(UnitTests PROPERTIES FOLDER "Tests")
 
 function(add_llvm_unittest test_dirname)
   add_unittest(UnitTests ${test_dirname} ${ARGN})
 endfunction()
 function(add_llvm_unittest_with_input_files test_dirname)
   add_unittest_with_input_files(UnitTests ${test_dirname} ${ARGN})
 endfunction()
 
 add_subdirectory(ADT)
 add_subdirectory(Analysis)
 add_subdirectory(AsmParser)
 add_subdirectory(BinaryFormat)
 add_subdirectory(Bitcode)
+add_subdirectory(Bitstream)
 add_subdirectory(CodeGen)
 add_subdirectory(DebugInfo)
 add_subdirectory(Demangle)
 add_subdirectory(ExecutionEngine)
 add_subdirectory(FuzzMutate)
 add_subdirectory(IR)
 add_subdirectory(LineEditor)
 add_subdirectory(Linker)

llvm/trunk/utils/GenLibDeps.pl

foreach my $lib (@libs ) {
     $libpath =~ s/(.+)AsmPrinter$/Target\/$1\/AsmPrinter/;
     $libpath =~ s/(.+)AsmParser$/Target\/$1\/AsmParser/;
     $libpath =~ s/(.+)Info$/Target\/$1\/TargetInfo/;
     $libpath =~ s/(.+)Disassembler$/Target\/$1\/Disassembler/;
     $libpath =~ s/SelectionDAG/CodeGen\/SelectionDAG/;
     $libpath =~ s/^AsmPrinter/CodeGen\/AsmPrinter/;
     $libpath =~ s/^BitReader/Bitcode\/Reader/;
     $libpath =~ s/^BitWriter/Bitcode\/Writer/;
+    $libpath =~ s/^BitstreamReader/Bitstream\/Reader/;
+    $libpath =~ s/^BitstreamWriter/Bitstream\/Writer/;
     $libpath =~ s/^MSIL/Target\/MSIL/;
     $libpath =~ s/^Core/IR/;
     $libpath =~ s/^Instrumentation/Transforms\/Instrumentation/;
     $libpath =~ s/^Interpreter/ExecutionEngine\/Interpreter/;
     $libpath =~ s/^JIT/ExecutionEngine\/JIT/;
     $libpath =~ s/^ScalarOpts/Transforms\/Scalar/;
     $libpath =~ s/^TransformUtils/Transforms\/Utils/;
     $libpath =~ s/^ipa/Analysis\/IPA/;
foreach my $lib (@libs ) {
     $libpath =~ s/(.+)AsmPrinter$/Target\/$1\/AsmPrinter/;
     $libpath =~ s/(.+)AsmParser$/Target\/$1\/AsmParser/;
     $libpath =~ s/(.+)Info$/Target\/$1\/TargetInfo/;
     $libpath =~ s/(.+)Disassembler$/Target\/$1\/Disassembler/;
     $libpath =~ s/SelectionDAG/CodeGen\/SelectionDAG/;
     $libpath =~ s/^AsmPrinter/CodeGen\/AsmPrinter/;
     $libpath =~ s/^BitReader/Bitcode\/Reader/;
     $libpath =~ s/^BitWriter/Bitcode\/Writer/;
+    $libpath =~ s/^BitstreamReader/Bitstream\/Reader/;
+    $libpath =~ s/^BitstreamWriter/Bitstream\/Writer/;
     $libpath =~ s/^MSIL/Target\/MSIL/;
     $libpath =~ s/^Core/VMCore/;
     $libpath =~ s/^Instrumentation/Transforms\/Instrumentation/;
     $libpath =~ s/^Interpreter/ExecutionEngine\/Interpreter/;
     $libpath =~ s/^JIT/ExecutionEngine\/JIT/;
     $libpath =~ s/^ScalarOpts/Transforms\/Scalar/;
     $libpath =~ s/^TransformUtils/Transforms\/Utils/;
     $libpath =~ s/^ipa/Analysis\/IPA/;