[CAS] Fix alignment error from MappedFileRegionArena (#159128)
Fix a bug that when an alignment error can happen when reading a slice
of file from existing MappedFileRegionArena.
diff --git a/llvm/lib/CAS/MappedFileRegionArena.cpp b/llvm/lib/CAS/MappedFileRegionArena.cpp
index 2deb87d..472843d 100644
--- a/llvm/lib/CAS/MappedFileRegionArena.cpp
+++ b/llvm/lib/CAS/MappedFileRegionArena.cpp
@@ -216,17 +216,18 @@
if (!Size)
return Size.takeError();
- Header *H = reinterpret_cast<Header *>(HeaderContent.data());
- if (H->HeaderOffset != HeaderOffset)
+ Header H;
+ memcpy(&H, HeaderContent.data(), sizeof(H));
+ if (H.HeaderOffset != HeaderOffset)
return createStringError(
std::make_error_code(std::errc::invalid_argument),
"specified header offset (" + utostr(HeaderOffset) +
- ") does not match existing config (" + utostr(H->HeaderOffset) +
+ ") does not match existing config (" + utostr(H.HeaderOffset) +
")");
// If the capacity doesn't match, use the existing capacity instead.
- if (H->Capacity != Capacity)
- Capacity = H->Capacity;
+ if (H.Capacity != Capacity)
+ Capacity = H.Capacity;
}
// If the size is smaller than capacity, we need to resize the file.
