Tim Northover 2d690684f6 Recommit DwarfEHPrepare: insert extra unwind paths for stack protector to instrument
This is a mitigation patch for
https://bugs.chromium.org/p/llvm/issues/detail?id=30, where existing stack
protection is skipped if a function is returned through by an unwinder rather
than the normal call/return path. The recent patch D139254 added the ability to
instrument a visible unwind path, at least in the IR case (I'm working on the
SelectionDAG instrumentation too) but there are still invisible unwinds it
can't reach.

So this patch adds logic to DwarfEHPrepare that goes through a function,
converting any call that might throw into an invoke to a simple resume cleanup,
and adding cleanup clauses to existing landingpads that lack them. Obviously we
don't really want to do this if it's wasted effort, so I also exposed
requiresStackProtector from the actual StackProtector code to skip the extra
paths if they won't be used.

Changes:
  * Move test to AArch64 directory as it relies on target presence.
  * Re-add Dominator-tree maintenance. Accidentally cherry-picked wrong patch.
  * Skip adding paths on Windows EH functions.

https://reviews.llvm.org/D143637
2023-03-16 13:43:17 +00:00
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++ SVE CodeGen Warnings ++

When the WARN check lines fail in the SVE codegen tests it most likely means you
have introduced a warning due to:
1. Adding an invalid call to VectorType::getNumElements() or EVT::getVectorNumElements()
   when the type is a scalable vector.
2. Relying upon an implicit cast conversion from TypeSize to uint64_t.

For generic code, please modify your code to work with ElementCount and TypeSize directly.
For target-specific code that only deals with fixed-width vectors, use the fixed-size interfaces.
Please refer to the code where those functions live for more details.