llvm-project

4d27530c - [Offloading] Offload Binary Format V2: Support Multiple Entries (#169425)

[Offloading] Offload Binary Format V2: Support Multiple Entries (#169425) This PR updates the OffloadBinary format from version 1 to version 2, enabling support for multiple offloading entries in a single binary. This allows combining multiple device images into a single binary with common global metadata while maintaining backwards compatibility with version 1 binaries. # Key Changes ## Binary Format Enhancements **Version 2 Format Changes:** - Changed from single-entry to multi-entry design - Updated `Header` structure: - Renamed `EntryOffset` → `EntriesOffset` (offset to entries array) - Renamed `EntrySize` → `EntriesCount` (number of entries) - Added `StringEntry::ValueSize` field to support explicit string value sizes (enables non-null-terminated strings) - Introduced `OffloadEntryFlags` enum with `OIF_Metadata` flag for metadata-only entries (entries without binary images) **API Changes:** - `OffloadBinary::create()` now returns `Expected<SmallVector<std::unique_ptr<OffloadBinary>>>` instead of single binary - Added optional `Index` parameter to extract specific entry: `create(Buffer, std::optional<uint64_t> Index)` - `OffloadBinary::write()` now accepts `ArrayRef<OffloadingImage>` instead of single image - Added `OffloadBinary::extractHeader()` for header extraction **Memory Management:** - Implemented `SharedMemoryBuffer` class to enable memory sharing across multiple `OffloadBinary` instances from the same file - Multiple entries from a single serialized binary share the underlying buffer ## Testing **Unit Tests (`unittests/Object/OffloadingTest.cpp`):** - `checkMultiEntryBinaryExtraction`: Tests extracting all entries from a multi-entry binary - `checkIndexBasedExtraction`: Tests extracting specific entries by index, including out-of-bounds validation - `checkEdgeCases`: Tests edge cases including: - Empty string metadata - Empty image data - Large string values (4KB) **Other Tests:** - Updated `test/ObjectYAML/Offload/multiple_members.yaml` to include metadata-only entry --------- Co-authored-by: Joseph Huber <huberjn@outlook.com>