2 files changed, 29 insertions, 3 deletions
diff --git a/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
index 7e1811daf09..2cc2a73a0d1 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
@@ -188,6 +188,10 @@ uint16_t DbiStream::getPublicSymbolStreamIndex() const {
   return Header->PublicSymbolStreamIndex;
 }
 
+uint16_t DbiStream::getGlobalSymbolStreamIndex() const {
+  return Header->GlobalSymbolStreamIndex;
+}
+
 bool DbiStream::isIncrementallyLinked() const {
   return (Header->Flags & FlagIncrementalMask) != 0;
 }
diff --git a/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp
index af047f73abd..09d71985031 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp
@@ -15,8 +15,12 @@ using namespace llvm;
 using namespace llvm::pdb;
 
 MappedBlockStream::MappedBlockStream(uint32_t StreamIdx, const PDBFile &File) : Pdb(File) {
-  StreamLength = Pdb.getStreamByteSize(StreamIdx);
-  BlockList = Pdb.getStreamBlockList(StreamIdx);
+  if (StreamIdx >= Pdb.getNumStreams()) {
+    StreamLength = 0;
+  } else {
+    StreamLength = Pdb.getStreamByteSize(StreamIdx);
+    BlockList = Pdb.getStreamBlockList(StreamIdx);
+  }
 }
 
 Error MappedBlockStream::readBytes(uint32_t Offset,
@@ -54,5 +58,23 @@ Error MappedBlockStream::readBytes(uint32_t Offset,
 
 Error MappedBlockStream::getArrayRef(uint32_t Offset, ArrayRef<uint8_t> &Buffer,
                                      uint32_t Length) const {
-  return make_error<RawError>(raw_error_code::feature_unsupported);
+  uint32_t BlockNum = Offset / Pdb.getBlockSize();
+  uint32_t OffsetInBlock = Offset % Pdb.getBlockSize();
+  uint32_t BytesAvailableInBlock = Pdb.getBlockSize() - OffsetInBlock;
+
+  // If this is the last block in the stream, not all of the data is valid.
+  if (BlockNum == BlockList.size() - 1) {
+    uint32_t AllocatedBytesInBlock = StreamLength % Pdb.getBlockSize();
+    if (AllocatedBytesInBlock < BytesAvailableInBlock)
+      BytesAvailableInBlock = AllocatedBytesInBlock;
+  }
+  if (BytesAvailableInBlock < Length)
+    return make_error<RawError>(raw_error_code::feature_unsupported);
+
+  uint32_t StreamBlockAddr = BlockList[BlockNum];
+  StringRef Data = Pdb.getBlockData(StreamBlockAddr, Pdb.getBlockSize());
+  Data = Data.substr(OffsetInBlock, Length);
+
+  Buffer = ArrayRef<uint8_t>(Data.bytes_begin(), Data.bytes_end());
+  return Error::success();
 }