[all-commits] [llvm/llvm-project] 450011: [Offload] Make compressed offload bundle header li...

[michaelselehov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4500116810d69622da80469993ca4d1e2e9ae2c8
      https://github.com/llvm/llvm-project/commit/4500116810d69622da80469993ca4d1e2e9ae2c8
  Author: michaelselehov <michael.selehov at amd.com>
  Date:   2026-07-09 (Thu, 09 Jul 2026)

  Changed paths:
    M llvm/lib/Object/OffloadBundle.cpp
    M llvm/test/tools/llvm-objdump/Offloading/fatbin-coff-compress.test

  Log Message:
  -----------
  [Offload] Make compressed offload bundle header little-endian (#206744)

The compressed offload bundle (CCOB) header integer fields (Version,
Method, FileSize, UncompressedFileSize, Hash) were serialized and read
in
host-native byte order. The on-disk format is little-endian, so on
big-endian hosts these fields were byte-swapped: writing produced a
malformed header, and reading misparsed the size, making
`llvm-objdump --offloading` crash/misbehave on s390x. This is also why
the
earlier bundle-size fix had to be reverted.

Make the header little-endian on every host:

- Read side: declare the `RawCompressedBundleHeader` fields as
`support::ulittle16_t` / `ulittle32_t` / `ulittle64_t`, so the bytes are
  always interpreted as little-endian regardless of host.
- Write side: emit the header with
`support::endian::Writer(OS, endianness::little)` instead of host-native
  `OS.write(&field, sizeof field)`.

Also revert the temporary big-endian test skip added in #205999
(host-byteorder-little-endian guard on fatbin-coff-compress.test): with
the
header now little-endian, the test runs correctly on big-endian hosts.

---------

Co-authored-by: Michael Selehov <michael.selehov at amd.com>
Co-authored-by: Nikita Popov <npopov at redhat.com> (LE approach)



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