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Faster stack-protector for Android/AArch64.

Authored by eugenis on Mar 30 2016, 4:32 PM.



Bionic has a defined thread-local location for the stack protector
cookie. Emit a direct load instead of going through __stack_chk_guard.

The current signature of getStackCookieLocation (returning addressspace + offset) is very x86 specific; let the function generate arbitrary IR for the cookie access instead. This is the same way getSafeStackPointerLocation works.

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eugenis updated this revision to Diff 52149.Mar 30 2016, 4:32 PM
eugenis retitled this revision from to Faster stack-protector for Android/AArch64..
eugenis updated this object.
eugenis added reviewers: echristo, danalbert.
eugenis set the repository for this revision to rL LLVM.
eugenis added subscribers: llvm-commits, pcc.

Adding Tim since he's in here as well.

LGTM, glad that AArch64 has Intrinsic::aarch64_thread_pointer to make your job easier. :)

I'm not the owner of SSP, but I'm recently working on it. Let's wait for others comments for a while, then I'm happy to stamp the patch.

For a bit background: I'm currently working on a cleanup on SSP (D17736), which also involves a similar change to yours. No worries, I will rebase to include your change.

Cool. Would it be better to avoid the use of IRBuilder, and switch the targetlowering hooks to the same signature as in D17736?
Value *..(Module &);

I slightly prefer taking a Module&, since by taking a Module&, getStackCookieLocation doesn't have a chance to insert a concrete instruction to a potentially specified place. That's taking Module& makes the interface narrower. But I don't have strong opinion on this.

Good point. AArch64 implementation actually needs to insert instructions for the intrinsic call. I guess we keep IRBuilder then, or replace it with Instruction *InsertBefore argument.

eugenis updated this revision to Diff 52737.Apr 5 2016, 2:25 PM
eugenis edited edge metadata.

Friendly ping.

timshen accepted this revision.Apr 5 2016, 3:04 PM
timshen edited edge metadata.
This revision is now accepted and ready to land.Apr 5 2016, 3:04 PM
eugenis closed this revision.Apr 5 2016, 3:47 PM

Thanks for the review.