Windows EH funclets need to always return to a single parent funclet. However, it is possible for earlier optimizations to combine funclets (probably based on one funclet having an unreachable terminator) in such a way that this condition is violated.
These changes add code to the WinEHPrepare pass to detect situations where a funclet has multiple parents and clone such funclets, fixing up the unwind and catch return edges so that each copy of the funclet returns to the correct parent funclet.
Differential Revision: http://reviews.llvm.org/D13274?id=39098
llvm-svn: 252249
The MSVC doesn't really support exception specifications so let's just
turn these into cleanuppads. Later, we might use terminatepad to more
efficiently encode the "noexcept"-ness of a function body.
llvm-svn: 247848
We are experimenting with a new approach to saving and restoring SSA
values used across funclets: let the register allocator do the dirty
work for us.
However, this means that we need to be able to clone commoned blocks
without relying on demotion.
llvm-svn: 247835
Andrew Kaylor