[PDB] General improvements to Stream library.

This adds various new functionality and cleanup surrounding the
use of the Stream library.  Major changes include:

* Renaming of all classes for more consistency / meaningfulness
* Addition of some new methods for reading multiple values at once.
* Full suite of unit tests for reader / writer functionality.
* Full set of doxygen comments for all classes.
* Streams now store their own endianness.
* Fixed some bugs in a few of the classes that were discovered
  by the unit tests.

llvm-svn: 296215
diff --git a/llvm/lib/DebugInfo/MSF/BinaryStreamReader.cpp b/llvm/lib/DebugInfo/MSF/BinaryStreamReader.cpp
index 567e6b1..ba5fd21 100644
--- a/llvm/lib/DebugInfo/MSF/BinaryStreamReader.cpp
+++ b/llvm/lib/DebugInfo/MSF/BinaryStreamReader.cpp
@@ -1,4 +1,4 @@
-//===- StreamReader.cpp - Reads bytes and objects from a stream -----------===//
+//===- BinaryStreamReader.cpp - Reads objects from a binary stream --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -10,53 +10,79 @@
 #include "llvm/DebugInfo/MSF/BinaryStreamReader.h"
 
 #include "llvm/DebugInfo/MSF/BinaryStreamRef.h"
-#include "llvm/DebugInfo/MSF/MSFError.h"
 
 using namespace llvm;
-using namespace llvm::msf;
 
-StreamReader::StreamReader(ReadableStreamRef S) : Stream(S), Offset(0) {}
+BinaryStreamReader::BinaryStreamReader(BinaryStreamRef S)
+    : Stream(S), Offset(0) {}
 
-Error StreamReader::readLongestContiguousChunk(ArrayRef<uint8_t> &Buffer) {
+Error BinaryStreamReader::readLongestContiguousChunk(
+    ArrayRef<uint8_t> &Buffer) {
   if (auto EC = Stream.readLongestContiguousChunk(Offset, Buffer))
     return EC;
   Offset += Buffer.size();
   return Error::success();
 }
 
-Error StreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) {
+Error BinaryStreamReader::readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size) {
   if (auto EC = Stream.readBytes(Offset, Size, Buffer))
     return EC;
   Offset += Size;
   return Error::success();
 }
 
-Error StreamReader::readZeroString(StringRef &Dest) {
+Error BinaryStreamReader::readInteger(uint64_t &Dest, uint32_t ByteSize) {
+  assert(ByteSize == 1 || ByteSize == 2 || ByteSize == 4 || ByteSize == 8);
+  ArrayRef<uint8_t> Bytes;
+
+  if (auto EC = readBytes(Bytes, ByteSize))
+    return EC;
+  switch (ByteSize) {
+  case 1:
+    Dest = Bytes[0];
+    return Error::success();
+  case 2:
+    Dest = llvm::support::endian::read16(Bytes.data(), Stream.getEndian());
+    return Error::success();
+  case 4:
+    Dest = llvm::support::endian::read32(Bytes.data(), Stream.getEndian());
+    return Error::success();
+  case 8:
+    Dest = llvm::support::endian::read64(Bytes.data(), Stream.getEndian());
+    return Error::success();
+  }
+  llvm_unreachable("Unreachable!");
+  return Error::success();
+}
+
+Error BinaryStreamReader::readCString(StringRef &Dest) {
+  // TODO: This could be made more efficient by using readLongestContiguousChunk
+  // and searching for null terminators in the resulting buffer.
+
   uint32_t Length = 0;
   // First compute the length of the string by reading 1 byte at a time.
   uint32_t OriginalOffset = getOffset();
   const char *C;
-  do {
+  while (true) {
     if (auto EC = readObject(C))
       return EC;
-    if (*C != '\0')
-      ++Length;
-  } while (*C != '\0');
+    if (*C == '\0')
+      break;
+    ++Length;
+  }
   // Now go back and request a reference for that many bytes.
   uint32_t NewOffset = getOffset();
   setOffset(OriginalOffset);
 
-  ArrayRef<uint8_t> Data;
-  if (auto EC = readBytes(Data, Length))
+  if (auto EC = readFixedString(Dest, Length))
     return EC;
-  Dest = StringRef(reinterpret_cast<const char *>(Data.begin()), Data.size());
 
   // Now set the offset back to where it was after we calculated the length.
   setOffset(NewOffset);
   return Error::success();
 }
 
-Error StreamReader::readFixedString(StringRef &Dest, uint32_t Length) {
+Error BinaryStreamReader::readFixedString(StringRef &Dest, uint32_t Length) {
   ArrayRef<uint8_t> Bytes;
   if (auto EC = readBytes(Bytes, Length))
     return EC;
@@ -64,26 +90,26 @@
   return Error::success();
 }
 
-Error StreamReader::readStreamRef(ReadableStreamRef &Ref) {
+Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref) {
   return readStreamRef(Ref, bytesRemaining());
 }
 
-Error StreamReader::readStreamRef(ReadableStreamRef &Ref, uint32_t Length) {
+Error BinaryStreamReader::readStreamRef(BinaryStreamRef &Ref, uint32_t Length) {
   if (bytesRemaining() < Length)
-    return make_error<MSFError>(msf_error_code::insufficient_buffer);
+    return errorCodeToError(make_error_code(std::errc::no_buffer_space));
   Ref = Stream.slice(Offset, Length);
   Offset += Length;
   return Error::success();
 }
 
-Error StreamReader::skip(uint32_t Amount) {
+Error BinaryStreamReader::skip(uint32_t Amount) {
   if (Amount > bytesRemaining())
-    return make_error<MSFError>(msf_error_code::insufficient_buffer);
+    return errorCodeToError(make_error_code(std::errc::no_buffer_space));
   Offset += Amount;
   return Error::success();
 }
 
-uint8_t StreamReader::peek() const {
+uint8_t BinaryStreamReader::peek() const {
   ArrayRef<uint8_t> Buffer;
   auto EC = Stream.readBytes(Offset, 1, Buffer);
   assert(!EC && "Cannot peek an empty buffer!");
diff --git a/llvm/lib/DebugInfo/MSF/BinaryStreamWriter.cpp b/llvm/lib/DebugInfo/MSF/BinaryStreamWriter.cpp
index 54415b9..08e4aef 100644
--- a/llvm/lib/DebugInfo/MSF/BinaryStreamWriter.cpp
+++ b/llvm/lib/DebugInfo/MSF/BinaryStreamWriter.cpp
@@ -1,4 +1,4 @@
-//===- StreamWrite.cpp - Writes bytes and objects to a stream -------------===//
+//===- BinaryStreamWriter.cpp - Writes objects to a BinaryStream ----------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -11,21 +11,42 @@
 
 #include "llvm/DebugInfo/MSF/BinaryStreamReader.h"
 #include "llvm/DebugInfo/MSF/BinaryStreamRef.h"
-#include "llvm/DebugInfo/MSF/MSFError.h"
 
 using namespace llvm;
-using namespace llvm::msf;
 
-StreamWriter::StreamWriter(WritableStreamRef S) : Stream(S), Offset(0) {}
+BinaryStreamWriter::BinaryStreamWriter(WritableBinaryStreamRef S)
+    : Stream(S), Offset(0) {}
 
-Error StreamWriter::writeBytes(ArrayRef<uint8_t> Buffer) {
+Error BinaryStreamWriter::writeBytes(ArrayRef<uint8_t> Buffer) {
   if (auto EC = Stream.writeBytes(Offset, Buffer))
     return EC;
   Offset += Buffer.size();
   return Error::success();
 }
 
-Error StreamWriter::writeZeroString(StringRef Str) {
+Error BinaryStreamWriter::writeInteger(uint64_t Value, uint32_t ByteSize) {
+  assert(ByteSize == 1 || ByteSize == 2 || ByteSize == 4 || ByteSize == 8);
+  uint8_t Bytes[8];
+  MutableArrayRef<uint8_t> Buffer(Bytes);
+  Buffer = Buffer.take_front(ByteSize);
+  switch (ByteSize) {
+  case 1:
+    Buffer[0] = static_cast<uint8_t>(Value);
+    break;
+  case 2:
+    llvm::support::endian::write16(Buffer.data(), Value, Stream.getEndian());
+    break;
+  case 4:
+    llvm::support::endian::write32(Buffer.data(), Value, Stream.getEndian());
+    break;
+  case 8:
+    llvm::support::endian::write64(Buffer.data(), Value, Stream.getEndian());
+    break;
+  }
+  return writeBytes(Buffer);
+}
+
+Error BinaryStreamWriter::writeCString(StringRef Str) {
   if (auto EC = writeFixedString(Str))
     return EC;
   if (auto EC = writeObject('\0'))
@@ -34,31 +55,21 @@
   return Error::success();
 }
 
-Error StreamWriter::writeFixedString(StringRef Str) {
-  ArrayRef<uint8_t> Bytes(Str.bytes_begin(), Str.bytes_end());
-  if (auto EC = Stream.writeBytes(Offset, Bytes))
-    return EC;
-
-  Offset += Str.size();
-  return Error::success();
+Error BinaryStreamWriter::writeFixedString(StringRef Str) {
+  return writeBytes(ArrayRef<uint8_t>(Str.bytes_begin(), Str.bytes_end()));
 }
 
-Error StreamWriter::writeStreamRef(ReadableStreamRef Ref) {
-  if (auto EC = writeStreamRef(Ref, Ref.getLength()))
-    return EC;
-  // Don't increment Offset here, it is done by the overloaded call to
-  // writeStreamRef.
-  return Error::success();
+Error BinaryStreamWriter::writeStreamRef(BinaryStreamRef Ref) {
+  return writeStreamRef(Ref, Ref.getLength());
 }
 
-Error StreamWriter::writeStreamRef(ReadableStreamRef Ref, uint32_t Length) {
-  Ref = Ref.slice(0, Length);
-
-  StreamReader SrcReader(Ref);
+Error BinaryStreamWriter::writeStreamRef(BinaryStreamRef Ref, uint32_t Length) {
+  BinaryStreamReader SrcReader(Ref.slice(0, Length));
   // This is a bit tricky.  If we just call readBytes, we are requiring that it
-  // return us the entire stream as a contiguous buffer.  For large streams this
-  // will allocate a huge amount of space from the pool.  Instead, iterate over
-  // each contiguous chunk until we've consumed the entire stream.
+  // return us the entire stream as a contiguous buffer.  There is no guarantee
+  // this can be satisfied by returning a reference straight from the buffer, as
+  // an implementation may not store all data in a single contiguous buffer.  So
+  // we iterate over each contiguous chunk, writing each one in succession.
   while (SrcReader.bytesRemaining() > 0) {
     ArrayRef<uint8_t> Chunk;
     if (auto EC = SrcReader.readLongestContiguousChunk(Chunk))
diff --git a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
index e52c88a..c9ba25c 100644
--- a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
+++ b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
@@ -47,22 +47,20 @@
 
 MappedBlockStream::MappedBlockStream(uint32_t BlockSize, uint32_t NumBlocks,
                                      const MSFStreamLayout &Layout,
-                                     const ReadableStream &MsfData)
+                                     BinaryStreamRef MsfData)
     : BlockSize(BlockSize), NumBlocks(NumBlocks), StreamLayout(Layout),
       MsfData(MsfData) {}
 
 std::unique_ptr<MappedBlockStream>
 MappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
                                 const MSFStreamLayout &Layout,
-                                const ReadableStream &MsfData) {
+                                BinaryStreamRef MsfData) {
   return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
       BlockSize, NumBlocks, Layout, MsfData);
 }
 
-std::unique_ptr<MappedBlockStream>
-MappedBlockStream::createIndexedStream(const MSFLayout &Layout,
-                                       const ReadableStream &MsfData,
-                                       uint32_t StreamIndex) {
+std::unique_ptr<MappedBlockStream> MappedBlockStream::createIndexedStream(
+    const MSFLayout &Layout, BinaryStreamRef MsfData, uint32_t StreamIndex) {
   assert(StreamIndex < Layout.StreamMap.size() && "Invalid stream index");
   MSFStreamLayout SL;
   SL.Blocks = Layout.StreamMap[StreamIndex];
@@ -73,7 +71,7 @@
 
 std::unique_ptr<MappedBlockStream>
 MappedBlockStream::createDirectoryStream(const MSFLayout &Layout,
-                                         const ReadableStream &MsfData) {
+                                         BinaryStreamRef MsfData) {
   MSFStreamLayout SL;
   SL.Blocks = Layout.DirectoryBlocks;
   SL.Length = Layout.SB->NumDirectoryBytes;
@@ -82,14 +80,14 @@
 
 std::unique_ptr<MappedBlockStream>
 MappedBlockStream::createFpmStream(const MSFLayout &Layout,
-                                   const ReadableStream &MsfData) {
+                                   BinaryStreamRef MsfData) {
   MSFStreamLayout SL;
   initializeFpmStreamLayout(Layout, SL);
   return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
 }
 
 Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
-                                   ArrayRef<uint8_t> &Buffer) const {
+                                   ArrayRef<uint8_t> &Buffer) {
   // Make sure we aren't trying to read beyond the end of the stream.
   if (Size > StreamLayout.Length)
     return make_error<MSFError>(msf_error_code::insufficient_buffer);
@@ -168,8 +166,8 @@
   return Error::success();
 }
 
-Error MappedBlockStream::readLongestContiguousChunk(
-    uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
+Error MappedBlockStream::readLongestContiguousChunk(uint32_t Offset,
+                                                    ArrayRef<uint8_t> &Buffer) {
   // Make sure we aren't trying to read beyond the end of the stream.
   if (Offset >= StreamLayout.Length)
     return make_error<MSFError>(msf_error_code::insufficient_buffer);
@@ -197,10 +195,10 @@
   return Error::success();
 }
 
-uint32_t MappedBlockStream::getLength() const { return StreamLayout.Length; }
+uint32_t MappedBlockStream::getLength() { return StreamLayout.Length; }
 
 bool MappedBlockStream::tryReadContiguously(uint32_t Offset, uint32_t Size,
-                                            ArrayRef<uint8_t> &Buffer) const {
+                                            ArrayRef<uint8_t> &Buffer) {
   if (Size == 0) {
     Buffer = ArrayRef<uint8_t>();
     return true;
@@ -241,7 +239,7 @@
 }
 
 Error MappedBlockStream::readBytes(uint32_t Offset,
-                                   MutableArrayRef<uint8_t> Buffer) const {
+                                   MutableArrayRef<uint8_t> Buffer) {
   uint32_t BlockNum = Offset / BlockSize;
   uint32_t OffsetInBlock = Offset % BlockSize;
 
@@ -319,21 +317,21 @@
 
 WritableMappedBlockStream::WritableMappedBlockStream(
     uint32_t BlockSize, uint32_t NumBlocks, const MSFStreamLayout &Layout,
-    const WritableStream &MsfData)
+    WritableBinaryStreamRef MsfData)
     : ReadInterface(BlockSize, NumBlocks, Layout, MsfData),
       WriteInterface(MsfData) {}
 
 std::unique_ptr<WritableMappedBlockStream>
 WritableMappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
                                         const MSFStreamLayout &Layout,
-                                        const WritableStream &MsfData) {
+                                        WritableBinaryStreamRef MsfData) {
   return llvm::make_unique<MappedBlockStreamImpl<WritableMappedBlockStream>>(
       BlockSize, NumBlocks, Layout, MsfData);
 }
 
 std::unique_ptr<WritableMappedBlockStream>
 WritableMappedBlockStream::createIndexedStream(const MSFLayout &Layout,
-                                               const WritableStream &MsfData,
+                                               WritableBinaryStreamRef MsfData,
                                                uint32_t StreamIndex) {
   assert(StreamIndex < Layout.StreamMap.size() && "Invalid stream index");
   MSFStreamLayout SL;
@@ -344,7 +342,7 @@
 
 std::unique_ptr<WritableMappedBlockStream>
 WritableMappedBlockStream::createDirectoryStream(
-    const MSFLayout &Layout, const WritableStream &MsfData) {
+    const MSFLayout &Layout, WritableBinaryStreamRef MsfData) {
   MSFStreamLayout SL;
   SL.Blocks = Layout.DirectoryBlocks;
   SL.Length = Layout.SB->NumDirectoryBytes;
@@ -353,28 +351,28 @@
 
 std::unique_ptr<WritableMappedBlockStream>
 WritableMappedBlockStream::createFpmStream(const MSFLayout &Layout,
-                                           const WritableStream &MsfData) {
+                                           WritableBinaryStreamRef MsfData) {
   MSFStreamLayout SL;
   initializeFpmStreamLayout(Layout, SL);
   return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
 }
 
 Error WritableMappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
-                                           ArrayRef<uint8_t> &Buffer) const {
+                                           ArrayRef<uint8_t> &Buffer) {
   return ReadInterface.readBytes(Offset, Size, Buffer);
 }
 
 Error WritableMappedBlockStream::readLongestContiguousChunk(
-    uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
+    uint32_t Offset, ArrayRef<uint8_t> &Buffer) {
   return ReadInterface.readLongestContiguousChunk(Offset, Buffer);
 }
 
-uint32_t WritableMappedBlockStream::getLength() const {
+uint32_t WritableMappedBlockStream::getLength() {
   return ReadInterface.getLength();
 }
 
 Error WritableMappedBlockStream::writeBytes(uint32_t Offset,
-                                            ArrayRef<uint8_t> Buffer) const {
+                                            ArrayRef<uint8_t> Buffer) {
   // Make sure we aren't trying to write beyond the end of the stream.
   if (Buffer.size() > getStreamLength())
     return make_error<MSFError>(msf_error_code::insufficient_buffer);
@@ -410,6 +408,4 @@
   return Error::success();
 }
 
-Error WritableMappedBlockStream::commit() const {
-  return WriteInterface.commit();
-}
+Error WritableMappedBlockStream::commit() { return WriteInterface.commit(); }