[llvm-branch-commits] [llvm] [Offloading] Add support for compressed OffloadBinary types (PR #222774)

[James Henderson via llvm-branch-commits]

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@@ -197,11 +176,53 @@ Error extractFromArchive(const Archive &Library,
   return Error::success();
 }
 
+bool isCompressed(const OffloadBinary::Header &Header) {
+  return Header.Version >= 3 && Header.InflatedSize != 0;
+}
+
+Expected<std::unique_ptr<MemoryBuffer>>
+decompressOffloadBinary(MemoryBufferRef Buf) {
+  const auto *Header =
+      reinterpret_cast<const OffloadBinary::Header *>(Buf.getBufferStart());
+  if (Header->EntriesOffset != sizeof(OffloadBinary::Header) ||
+      Header->EntriesOffset > Header->Size ||
+      Header->InflatedSize < Header->EntriesOffset)
+    return errorCodeToError(object_error::unexpected_eof);
+
+  // Get the compressed binary blob after the header.
+  StringRef Compressed = Buf.getBuffer()
+                             .take_front(Header->Size)
+                             .drop_front(Header->EntriesOffset);
+  uint64_t BodySize = Header->InflatedSize - Header->EntriesOffset;
+
+  ArrayRef<uint8_t> CompressedBytes = arrayRefFromStringRef(Compressed);
+  if (const char *Reason = compression::getReasonIfUnsupported(CompressedBytes))
+    return createStringError(Reason);
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jh7370 wrote:

Looks like this is redundant, since `decompress` does the check internally and feeds it into the returned error?

https://github.com/llvm/llvm-project/pull/222774