[llvm-dev] Handling of section vs global name conflicts

[Rafael Espíndola via llvm-dev]

The correct fix is probably to know that section symbols are local and
just allow them to have any name.

Cheers,
Rafael


On 18 March 2016 at 13:25, Evgenii Stepanov via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> Hi,
>
> currently LLVM does not handle the conflict between a section and a
> global _definition_ with the same name well. A section defines a local
> symbol with the same name (pointing to the start of the section).
> Depending on the order of declarations, LLVM either silently overrides
> the section symbol with the global, or crashes with
> fatal error: error in backend: symbol 'xxx' is already defined
> The latter happens when the conflicting global is emitted when the
> section is already created.
>
> See https://llvm.org/bugs/show_bug.cgi?id=26941 for more details and motivation.
>
> I think it would make sense to disallow global definitions with the
> same name as a section. Unfortunately, sections are not values, and it
> makes it hard to track them (ValueSymbolTable could implement value
> renaming in case of conflicts, but there is no direct way of knowing
> if the section name is currently in use or not without rescanning the
> module). Changing IR representation of sections just for this sounds
> like overkill.
>
> Another option is to allow the conflict, and make the global always
> override the section symbol. This is easy to do in the integrated
> assembler, but it appears that GAS simply does not work this way.
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