Add support for writing through StreamInterface.

This adds method and tests for writing to a PDB stream.  With
this, even a PDB stream which is discontiguous can be treated
as a sequential stream of bytes for the purposes of writing.

Reviewed By: ruiu
Differential Revision: http://reviews.llvm.org/D21157

llvm-svn: 272369

1 files changed, 45 insertions, 7 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/ByteStream.cpp b/llvm/lib/DebugInfo/CodeView/ByteStream.cpp
index c0ac0b7a8ff..83b2f8ec307 100644
--- a/llvm/lib/DebugInfo/CodeView/ByteStream.cpp
+++ b/llvm/lib/DebugInfo/CodeView/ByteStream.cpp
@@ -15,23 +15,61 @@
 using namespace llvm;
 using namespace llvm::codeview;
 
-ByteStream::ByteStream() {}
+static Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Src,
+                        ArrayRef<uint8_t> Dest) {
+  return make_error<CodeViewError>(cv_error_code::operation_unsupported,
+                                   "ByteStream is immutable.");
+}
 
-ByteStream::ByteStream(ArrayRef<uint8_t> Data) : Data(Data) {}
+static Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Src,
+                        MutableArrayRef<uint8_t> Dest) {
+  if (Dest.size() < Src.size())
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+  if (Offset > Src.size() - Dest.size())
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
 
-ByteStream::~ByteStream() {}
+  ::memcpy(Dest.data() + Offset, Src.data(), Src.size());
+  return Error::success();
+}
 
-Error ByteStream::readBytes(uint32_t Offset, uint32_t Size,
-                            ArrayRef<uint8_t> &Buffer) const {
+template <bool Writable>
+Error ByteStream<Writable>::readBytes(uint32_t Offset, uint32_t Size,
+                                      ArrayRef<uint8_t> &Buffer) const {
+  if (Offset > Data.size())
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
   if (Data.size() < Size + Offset)
     return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
   Buffer = Data.slice(Offset, Size);
   return Error::success();
 }
 
-uint32_t ByteStream::getLength() const { return Data.size(); }
+template <bool Writable>
+Error ByteStream<Writable>::readLongestContiguousChunk(
+    uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
+  if (Offset >= Data.size())
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+  Buffer = Data.slice(Offset);
+  return Error::success();
+}
+
+template <bool Writable>
+Error ByteStream<Writable>::writeBytes(uint32_t Offset,
+                                       ArrayRef<uint8_t> Buffer) const {
+  return ::writeBytes(Offset, Buffer, Data);
+}
+
+template <bool Writable> uint32_t ByteStream<Writable>::getLength() const {
+  return Data.size();
+}
 
-StringRef ByteStream::str() const {
+template <bool Writable> StringRef ByteStream<Writable>::str() const {
   const char *CharData = reinterpret_cast<const char *>(Data.data());
   return StringRef(CharData, Data.size());
 }
+
+namespace llvm {
+namespace codeview {
+template class ByteStream<true>;
+template class ByteStream<false>;
+}
+}