[PATCH] D34782: [scudo] Change aligned alloc functions to be more compliant & perf changes

[Kostya Kortchinsky via Phabricator via llvm-commits]

cryptoad created this revision.

We were not following the `man` documented behaviors for invalid arguments to
`memalign` and associated functions. Using `CHECK` for those was a bit extreme,
so we relax the behavior to return null pointers as expected when this happens.
Adapt the associated test.

I am using this change also to change a few more minor performance improvements:

- mark as `UNLIKELY` a bunch of unlikely conditions;
- the current `CHECK` in `__sanitizer::RoundUpTo` is redundant for us in *all* calls. So I am introducing our own version without said `CHECK`.
- change our combined allocator `GetActuallyAllocatedSize`. We already know if the pointer is from the Primary or Secondary, so the `PointerIsMine` check is redundant as well, and costly for the 32-bit Primary. So we get the size by directly using the available Primary functions.

Finally, change a `int` to `uptr` to avoid a warning/error when compiling on
Android.


https://reviews.llvm.org/D34782

Files:
  lib/scudo/scudo_allocator.cpp
  lib/scudo/scudo_allocator.h
  lib/scudo/scudo_allocator_combined.h
  lib/scudo/scudo_tls_android.cpp
  test/scudo/memalign.cpp

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