[PATCH] D40523: [llvm-objcopy] Add --only-keep-debug

[Jake Ehrlich via Phabricator via llvm-commits]

jakehehrlich added a comment.

> I did some thinking, and I'm pretty confident I understand more about the need for section offsets to change to the start of the segment (i.e. point 3 above). By not moving the section offset, but reducing the segment file size, the section to segment mapping (as displayed with readelf -l) no longer matches following stripping, whereas GNU objcopy behaviour (i.e. moving the section to the start offset of the segment) means that it continues to match (readelf appears to treat zero-sized sections at the end of a segment as being in that segment). Furthermore, if you consider the case where the sections were NOBITS in the linker input, they would be emitted at the start offsets. Not moving the sections is starting to feel simply wrong to me.

Ah I just realized that I have to set the OriginalOffset to be the same as the parent segment. I was thinking for some reason that by changing the FileSize of the segments layout would handle it all for me but of course that's not right at all. Sorry about that.


Repository:
  rL LLVM

https://reviews.llvm.org/D40523