[PATCH] D51652: lld-link: Write an empty "repro" debug directory entry if /Brepro is passed

[Nico Weber via Phabricator via llvm-commits]

thakis created this revision.
thakis added a reviewer: rnk.
Herald added a subscriber: hiraditya.

If the coff timestamp is set to a hash, like lld-link does if /Brepro is passed, the coff spec suggests that a IMAGE_DEBUG_TYPE_REPRO entry is in the debug directory. This lets lld-link write such a section. See bug for details.

link.exe creates a zero-length repro debug directory entry with `/debug /Brepro`/ Without debug, it puts a longer hash in the repro section. This here lets lld-link always write a zero-length repro debug directory entry.

If the repro entry is the only debug directory entry, it's now no longer guaranteed that DebugDirectoryStart + DataEntry->Size is within a section, so also tweak initDebugDirectoryPtr() to look like initBaseRelocPtr(). Also fix llvm-readobj to not error out when dumping the contents of a zero-length debug directory entry. Both these llvm changes are needed to get llvm-readobj working for the new lld test in this patch.

Fixes PR38429.


https://reviews.llvm.org/D51652

Files:
  lld/COFF/Writer.cpp
  lld/test/COFF/rsds.test
  llvm/lib/Object/COFFObjectFile.cpp
  llvm/tools/llvm-readobj/COFFDumper.cpp

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