[PATCH] D18846: [safestack] Add canary to unsafe stack frames

[Tim Shen via llvm-commits]

timshen added a comment.

In http://reviews.llvm.org/D18846#395911, @eugenis wrote:

> moveStaticAllocasToUnsafeStack must be called once per function.


As discussed, you may want to call moveStaticAllocasToUnsafeStack, then possibly in SDAG Intrinsic::stackprotector handling you need to handle non-Alloca cases explicitly.

Or if you think there are reasons to keep the code a little bit duplicated between SSP and SafeStack, I'm fine with it, since I'm not the owner of either. :)

> Also, there may be no unsafe stack frame at all, then there would be no need for the guard at all. SafeStack is currently smarter about this than StackProtector; it uses SCEV to prove that allocas can never overflow.


What if the source code does overflow? Does SafeStack just fails to build (seems unlikely?), or SSP still needs to be inserted?


Repository:
  rL LLVM

http://reviews.llvm.org/D18846