[PATCH] D96004: [AArch64] Stack probing for function prologues

[Tamar Christina via Phabricator via llvm-commits]

tnfchris added a comment.

> For GCC this is guard-page - 1k. The reasoning is that with any outgoing argument larger than 1k we would probe such that we maintain the invariant, but probing that 1k means we have a whole guard-size -1k left that we can use without probing. These sizes were chose as they cover about 99% of all programs (for a subset of all :)).

As an addendum, as I mentioned above, wrt the outgoing argument not being larger than 1k. That's the buffer we guarantee.  We're able to do so because during a function call the storing of `LR` counts as an implicit probe. So in order for this scheme to be secure you'd need to check that LLVM (like GCC) always stores `LR`, even for `no-return` leaf functions.


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https://reviews.llvm.org/D96004