[llvm-pdbdump] Propagate errors a little more consistently

PDBFile::getBlockData didn't really return any indication that it
failed.  It merely returned an empty buffer.

llvm-svn: 275009

2 files changed, 18 insertions, 9 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp
index 3463871227b..92b2048c3c2 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/MappedBlockStream.cpp
@@ -139,8 +139,10 @@ Error MappedBlockStream::readLongestContiguousChunk(
   uint32_t BlockSpan = Last - First + 1;
   uint32_t ByteSpan =
       BytesFromFirstBlock + (BlockSpan - 1) * Pdb.getBlockSize();
-  Buffer = Pdb.getBlockData(BlockList[First], Pdb.getBlockSize());
-  Buffer = Buffer.drop_front(OffsetInFirstBlock);
+  auto Result = Pdb.getBlockData(BlockList[First], Pdb.getBlockSize());
+  if (!Result)
+    return Result.takeError();
+  Buffer = Result->drop_front(OffsetInFirstBlock);
   Buffer = ArrayRef<uint8_t>(Buffer.data(), ByteSpan);
   return Error::success();
 }
@@ -173,8 +175,12 @@ bool MappedBlockStream::tryReadContiguously(uint32_t Offset, uint32_t Size,
   }
 
   uint32_t FirstBlockAddr = BlockList[BlockNum];
-  auto Data = Pdb.getBlockData(FirstBlockAddr, Pdb.getBlockSize());
-  Data = Data.drop_front(OffsetInBlock);
+  auto Result = Pdb.getBlockData(FirstBlockAddr, Pdb.getBlockSize());
+  if (!Result) {
+    consumeError(Result.takeError());
+    return false;
+  }
+  auto Data = Result->drop_front(OffsetInBlock);
   Buffer = ArrayRef<uint8_t>(Data.data(), Size);
   return true;
 }
@@ -197,8 +203,11 @@ Error MappedBlockStream::readBytes(uint32_t Offset,
   while (BytesLeft > 0) {
     uint32_t StreamBlockAddr = BlockList[BlockNum];
 
-    auto Data = Pdb.getBlockData(StreamBlockAddr, Pdb.getBlockSize());
+    auto Result = Pdb.getBlockData(StreamBlockAddr, Pdb.getBlockSize());
+    if (!Result)
+      return Result.takeError();
 
+    auto Data = *Result;
     const uint8_t *ChunkStart = Data.data() + OffsetInBlock;
     uint32_t BytesInChunk =
         std::min(BytesLeft, Pdb.getBlockSize() - OffsetInBlock);
diff --git a/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp b/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp
index 2d8e0d0ed91..b289fd0124b 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp
@@ -73,13 +73,13 @@ PDBFile::getStreamBlockList(uint32_t StreamIndex) const {
 
 size_t PDBFile::getFileSize() const { return Buffer->getLength(); }
 
-ArrayRef<uint8_t> PDBFile::getBlockData(uint32_t BlockIndex,
-                                        uint32_t NumBytes) const {
+Expected<ArrayRef<uint8_t>> PDBFile::getBlockData(uint32_t BlockIndex,
+                                                  uint32_t NumBytes) const {
   uint64_t StreamBlockOffset = blockToOffset(BlockIndex, getBlockSize());
 
   ArrayRef<uint8_t> Result;
   if (auto EC = Buffer->readBytes(StreamBlockOffset, NumBytes, Result))
-    consumeError(std::move(EC));
+    return std::move(EC);
   return Result;
 }
 
@@ -460,4 +460,4 @@ Error PDBFile::commit() {
   }
 
   return Buffer->commit();
-}
\ No newline at end of file
+}