[PATCH] D56584: [llvm-objcopy] [COFF] Fix writing object files without symbols/string table

Fri Jan 11 03:13:41 PST 2019

jhenderson added a comment.

In D56584#1353933 <https://reviews.llvm.org/D56584#1353933>, @mstorsjo wrote:

> In D56584#1353916 <https://reviews.llvm.org/D56584#1353916>, @jhenderson wrote:
>
> > I'm not quite sure I follow why this only affects executable files? Why is this an issue in PE but not plain COFF?
>
>
> Initially I tried to make the output of llvm-objcopy as close as possible to the output from various tools (llvm-mc and MSVC), and to achieve this, I only skipped including the symbol/string table in executables, while keeping it present in object files.
>
> I know that exactly matching the output of another tool shouldn't be a goal in itself, but I don't know if there are tools out there that would flat out reject an object file with an omitted symbol/string table, as opposed to an empty symbol/string table. So keeping this distinction probably is safer.

So the behaviour change is that for objects, the object now has a pointer to the symbol table, which it didn't before. I think I get it now. The problem is the writeSymbolStringTables function, and you want that to always write a size for object files, even if the table is empty, right?

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https://reviews.llvm.org/D56584