12 files changed, 163 insertions, 8 deletions
diff --git a/llvm/include/llvm/DebugInfo/CodeView/ByteStream.h b/llvm/include/llvm/DebugInfo/CodeView/ByteStream.h
index 44fcbaabd6d..ec841d9f45e 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/ByteStream.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/ByteStream.h
@@ -16,19 +16,27 @@
 #include "llvm/Support/Error.h"
 #include <cstdint>
 #include <memory>
+#include <type_traits>
 
 namespace llvm {
 namespace codeview {
 class StreamReader;
 
-class ByteStream : public StreamInterface {
+template <bool Writable = false> class ByteStream : public StreamInterface {
+  typedef typename std::conditional<Writable, MutableArrayRef<uint8_t>,
+                                    ArrayRef<uint8_t>>::type ArrayType;
+
 public:
-  ByteStream();
-  explicit ByteStream(ArrayRef<uint8_t> Data);
-  ~ByteStream() override;
+  ByteStream() {}
+  explicit ByteStream(ArrayType Data) : Data(Data) {}
+  ~ByteStream() override {}
 
   Error readBytes(uint32_t Offset, uint32_t Size,
                   ArrayRef<uint8_t> &Buffer) const override;
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) const override;
+
+  Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Buffer) const override;
 
   uint32_t getLength() const override;
 
@@ -36,9 +44,12 @@ public:
   StringRef str() const;
 
 private:
-  ArrayRef<uint8_t> Data;
+  ArrayType Data;
 };
 
+extern template class ByteStream<true>;
+extern template class ByteStream<false>;
+
 } // end namespace pdb
 } // end namespace llvm
 
diff --git a/llvm/include/llvm/DebugInfo/CodeView/CodeViewError.h b/llvm/include/llvm/DebugInfo/CodeView/CodeViewError.h
index a3d4171f693..69ff29aab6f 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/CodeViewError.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/CodeViewError.h
@@ -19,6 +19,7 @@ namespace codeview {
 enum class cv_error_code {
   unspecified = 1,
   insufficient_buffer,
+  operation_unsupported,
   corrupt_record,
 };
 
diff --git a/llvm/include/llvm/DebugInfo/CodeView/StreamArray.h b/llvm/include/llvm/DebugInfo/CodeView/StreamArray.h
index 0241bb82be2..b6ecc75e439 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/StreamArray.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/StreamArray.h
@@ -97,6 +97,8 @@ public:
 
   const Extractor &getExtractor() const { return E; }
 
+  StreamRef getUnderlyingStream() const { return Stream; }
+
 private:
   StreamRef Stream;
   Extractor E;
diff --git a/llvm/include/llvm/DebugInfo/CodeView/StreamInterface.h b/llvm/include/llvm/DebugInfo/CodeView/StreamInterface.h
index f875f1896a4..a8b9dbfc2b6 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/StreamInterface.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/StreamInterface.h
@@ -28,9 +28,22 @@ class StreamInterface {
 public:
   virtual ~StreamInterface() {}
 
+  // Given an offset into the stream and a number of bytes, attempt to read
+  // the bytes and set the output ArrayRef to point to a reference into the
+  // stream, without copying any data.
   virtual Error readBytes(uint32_t Offset, uint32_t Size,
                           ArrayRef<uint8_t> &Buffer) const = 0;
 
+  // Given an offset into the stream, read as much as possible without copying
+  // any data.
+  virtual Error readLongestContiguousChunk(uint32_t Offset,
+                                           ArrayRef<uint8_t> &Buffer) const = 0;
+
+  // Attempt to write the given bytes into the stream at the desired offset.
+  // This will always necessitate a copy.  Cannot shrink or grow the stream,
+  // only writes into existing allocated space.
+  virtual Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Data) const = 0;
+
   virtual uint32_t getLength() const = 0;
 };
 
diff --git a/llvm/include/llvm/DebugInfo/CodeView/StreamReader.h b/llvm/include/llvm/DebugInfo/CodeView/StreamReader.h
index a42cc8bc7b8..2f497c2c43f 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/StreamReader.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/StreamReader.h
@@ -28,6 +28,7 @@ class StreamReader {
 public:
   StreamReader(StreamRef Stream);
 
+  Error readLongestContiguousChunk(ArrayRef<uint8_t> &Buffer);
   Error readBytes(ArrayRef<uint8_t> &Buffer, uint32_t Size);
   Error readInteger(uint16_t &Dest);
   Error readInteger(uint32_t &Dest);
diff --git a/llvm/include/llvm/DebugInfo/CodeView/StreamRef.h b/llvm/include/llvm/DebugInfo/CodeView/StreamRef.h
index 036802d2499..93b116b78c8 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/StreamRef.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/StreamRef.h
@@ -24,7 +24,8 @@ public:
   StreamRef(const StreamInterface &Stream, uint32_t Offset, uint32_t Length)
       : Stream(&Stream), ViewOffset(Offset), Length(Length) {}
 
-  StreamRef(const StreamRef &Stream, uint32_t Offset, uint32_t Length) = delete;
+  // Use StreamRef.slice() instead.
+  StreamRef(const StreamRef &S, uint32_t Offset, uint32_t Length) = delete;
 
   Error readBytes(uint32_t Offset, uint32_t Size,
                   ArrayRef<uint8_t> &Buffer) const override {
@@ -33,7 +34,32 @@ public:
     return Stream->readBytes(ViewOffset + Offset, Size, Buffer);
   }
 
+  // Given an offset into the stream, read as much as possible without copying
+  // any data.
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) const override {
+    if (Offset >= Length)
+      return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+
+    if (auto EC = Stream->readLongestContiguousChunk(Offset, Buffer))
+      return EC;
+    // This StreamRef might refer to a smaller window over a larger stream.  In
+    // that case we will have read out more bytes than we should return, because
+    // we should not read past the end of the current view.
+    uint32_t MaxLength = Length - Offset;
+    if (Buffer.size() > MaxLength)
+      Buffer = Buffer.slice(0, MaxLength);
+    return Error::success();
+  }
+
+  Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Data) const override {
+    if (Data.size() + Offset > Length)
+      return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+    return Stream->writeBytes(ViewOffset + Offset, Data);
+  }
+
   uint32_t getLength() const override { return Length; }
+
   StreamRef drop_front(uint32_t N) const {
     if (!Stream)
       return StreamRef();
diff --git a/llvm/include/llvm/DebugInfo/CodeView/StreamWriter.h b/llvm/include/llvm/DebugInfo/CodeView/StreamWriter.h
new file mode 100644
index 00000000000..ad9277b8e22
--- /dev/null
+++ b/llvm/include/llvm/DebugInfo/CodeView/StreamWriter.h
@@ -0,0 +1,82 @@
+//===- StreamWriter.h - Writes bytes and objects to a stream ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_CODEVIEW_STREAMWRITER_H
+#define LLVM_DEBUGINFO_CODEVIEW_STREAMWRITER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/CodeView/StreamArray.h"
+#include "llvm/DebugInfo/CodeView/StreamInterface.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
+
+#include <string>
+
+namespace llvm {
+namespace codeview {
+
+class StreamRef;
+
+class StreamWriter {
+public:
+  StreamWriter(StreamRef Stream);
+
+  Error writeBytes(ArrayRef<uint8_t> Buffer);
+  Error writeInteger(uint16_t Dest);
+  Error writeInteger(uint32_t Dest);
+  Error writeZeroString(StringRef Str);
+  Error writeFixedString(StringRef Str);
+  Error writeStreamRef(StreamRef Ref);
+  Error writeStreamRef(StreamRef Ref, uint32_t Size);
+
+  template <typename T> Error writeEnum(T Num) {
+    return writeInteger(
+        static_cast<typename std::underlying_type<T>::type>(Num));
+  }
+
+  template <typename T> Error writeObject(const T &Obj) {
+    return writeBytes(
+        ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(&Obj), sizeof(T)));
+  }
+
+  template <typename T> Error writeArray(ArrayRef<T> Array) {
+    if (Array.size() == 0)
+      return Error::success();
+
+    if (Array.size() > UINT32_MAX / sizeof(T))
+      return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+
+    return writeBytes(
+        ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(Array.data()),
+                          Array.size() * sizeof(T)));
+  }
+
+  template <typename T, typename U>
+  Error writeArray(VarStreamArray<T, U> Array) {
+    return writeStreamRef(Array.getUnderlyingStream());
+  }
+
+  template <typename T> Error writeArray(FixedStreamArray<T> Array) {
+    return writeStreamRef(Array.getUnderlyingStream());
+  }
+
+  void setOffset(uint32_t Off) { Offset = Off; }
+  uint32_t getOffset() const { return Offset; }
+  uint32_t getLength() const { return Stream.getLength(); }
+  uint32_t bytesRemaining() const { return getLength() - getOffset(); }
+
+private:
+  StreamRef Stream;
+  uint32_t Offset;
+};
+} // namespace codeview
+} // namespace llvm
+
+#endif // LLVM_DEBUGINFO_CODEVIEW_STREAMREADER_H
diff --git a/llvm/include/llvm/DebugInfo/PDB/Raw/IPDBFile.h b/llvm/include/llvm/DebugInfo/PDB/Raw/IPDBFile.h
index 0f8736d55c4..717a7880f3c 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Raw/IPDBFile.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Raw/IPDBFile.h
@@ -14,6 +14,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/CodeView/StreamArray.h"
 #include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
 
 #include <stdint.h>
 
@@ -34,6 +35,8 @@ public:
 
   virtual ArrayRef<uint8_t> getBlockData(uint32_t BlockIndex,
                                          uint32_t NumBytes) const = 0;
+  virtual Error setBlockData(uint32_t BlockIndex, uint32_t Offset,
+                             ArrayRef<uint8_t> Data) const = 0;
 };
 }
 }
diff --git a/llvm/include/llvm/DebugInfo/PDB/Raw/MappedBlockStream.h b/llvm/include/llvm/DebugInfo/PDB/Raw/MappedBlockStream.h
index 0148ed6086b..8ee0ab66446 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Raw/MappedBlockStream.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Raw/MappedBlockStream.h
@@ -31,6 +31,9 @@ class MappedBlockStream : public codeview::StreamInterface {
 public:
   Error readBytes(uint32_t Offset, uint32_t Size,
                   ArrayRef<uint8_t> &Buffer) const override;
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) const override;
+  Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Buffer) const override;
 
   uint32_t getLength() const override;
 
@@ -51,8 +54,9 @@ protected:
   const IPDBFile &Pdb;
   std::unique_ptr<IPDBStreamData> Data;
 
+  typedef MutableArrayRef<uint8_t> CacheEntry;
   mutable llvm::BumpPtrAllocator Pool;
-  mutable DenseMap<uint32_t, uint8_t *> CacheMap;
+  mutable DenseMap<uint32_t, std::vector<CacheEntry>> CacheMap;
 };
 
 } // end namespace pdb
diff --git a/llvm/include/llvm/DebugInfo/PDB/Raw/PDBFile.h b/llvm/include/llvm/DebugInfo/PDB/Raw/PDBFile.h
index f6ee987adcd..20e22e318c6 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Raw/PDBFile.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Raw/PDBFile.h
@@ -54,6 +54,8 @@ public:
 
   ArrayRef<uint8_t> getBlockData(uint32_t BlockIndex,
                                  uint32_t NumBytes) const override;
+  Error setBlockData(uint32_t BlockIndex, uint32_t Offset,
+                     ArrayRef<uint8_t> Data) const override;
 
   ArrayRef<support::ulittle32_t> getDirectoryBlockArray() const;
 
diff --git a/llvm/include/llvm/DebugInfo/PDB/Raw/RawError.h b/llvm/include/llvm/DebugInfo/PDB/Raw/RawError.h
index 5a1614fc82e..076f75ba031 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Raw/RawError.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Raw/RawError.h
@@ -22,7 +22,9 @@ enum class raw_error_code {
   corrupt_file,
   insufficient_buffer,
   no_stream,
-  index_out_of_bounds
+  index_out_of_bounds,
+  invalid_block_address,
+  not_writable,
 };
 
 /// Base class for errors originating when parsing raw PDB files
diff --git a/llvm/include/llvm/Support/MathExtras.h b/llvm/include/llvm/Support/MathExtras.h
index e9639450a70..94ca40d5789 100644
--- a/llvm/include/llvm/Support/MathExtras.h
+++ b/llvm/include/llvm/Support/MathExtras.h
@@ -681,6 +681,14 @@ inline int64_t SignExtend64(uint64_t X, unsigned B) {
   return int64_t(X << (64 - B)) >> (64 - B);
 }
 
+/// \brief Subtract two unsigned integers, X and Y, of type T and return their
+/// absolute value.
+template <typename T>
+typename std::enable_if<std::is_unsigned<T>::value, T>::type
+AbsoluteDifference(T X, T Y) {
+  return std::max(X, Y) - std::min(X, Y);
+}
+
 /// \brief Add two unsigned integers, X and Y, of type T.
 /// Clamp the result to the maximum representable value of T on overflow.
 /// ResultOverflowed indicates if the result is larger than the maximum