[PATCH] D43574: [ELF] - Introduce getInputSections() helper.

George Rimar via llvm-commits llvm-commits at lists.llvm.org
Thu Feb 22 09:22:01 PST 2018


>>> jhenderson wrote:
>>>> This isn't a direct equivalent of what was there before, as it only takes account of InputSectionDescription commands, and not other commands, such as BYTE() or symbol >>assignments. This has an effect on the layout, though I haven't conclusively determined what (it affects the "Rank" somehow). See PR36475.
>>> You right.
>>> What we do is set output section flags to flags of synthetic input section. Then we remove this empty section here and mark output
>>> section as dead.
>>> `adjustSectionsBeforeSorting` might resurrect it and reassign flags to different ones.
>>> If script would not contain empty synthetic section in output section description, I think flags would be the same as now.
>>> So, this is definitely not a direct equivalent, but I am not sure if it is an issue ?
>>
>>We should at least have a test showing the difference.
>>
>>Cheers,
>>Rafael
>
>That is true. I wonder if we want to revert this particular place for now or not.
>
>It also can be worth to think about fixing following case:
>if output section has input sections A and B and A is removed, then output section remains live,
>and has flags from both A and B still. That is not quite correct as well.
>
>So I can suggest to revert this particular place to make initial change be clear NFC and I can work on
>patch for above then.
>
>What do you think ?
>
>George.

I'll prepare and post testcase on review soon though.

George.


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