[llvm-commits] [PATCH] Implement local-dynamic TLS model for x86 (PR3985)

[Hans Wennborg]

On Wed, May 23, 2012 at 5:44 PM, Hans Wennborg <hans at chromium.org> wrote:
> Taking another stab at this.
>
> The attached patch implements support for the local-dynamic TLS model on x86.
>
> The lowering code will generate calls to get the address for the TLS
> block for each variable access. Later, a MachineFunctionPass is used
> to remove all such calls except one, achieving the goal of at most one
> call to __get_tls_addr per function.
>
> Again, I'm new to codegen, so any comments and suggestions are much
> appreciated. Please review.

Sorry for all the self replies.

I just realized that moving the __get_tls_addr call to the top of the
function isn't very nice if there are execution paths that wouldn't
otherwise have to call it.

Attached is a new patch that will not move the calls around, but
removes all calls except the first on each execution path. It also
doesn't add the pass when CodeGenOpt::None is used.

Please take a look.

Thanks,
Hans
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