Catch objects with a displacement of zero do not initialize a catch
object. The displacement is relative to %rsp at the end of the
function's prologue for x86_64 targets.
If we place an object at the top-of-stack, we will end up wit a
displacement of zero resulting in our catch object remaining
uninitialized.
Address this by creating our catch objects as fixed objects. We will
ensure that the UnwindHelp object is created after the catch objects so
that no catch object will have a displacement of zero.
Differential Revision: http://reviews.llvm.org/D17823
llvm-svn: 262546
StackColoring rewrites the frame indicies of operations involving
allocas if it can find that the life time of two objects do not overlap.
MSVC EH needs to be kept aware of this if happens in the event that a
catch object has moved around. However, we represent the non-existance
of a catch object with a sentinel frame index (INT_MAX). This sentinel
also happens to be the EmptyKey of the SlotRemap DenseMap. Testing for
whether or not we need to translate the frame index fails in this case
because we call the count method on the DenseMap with the EmptyKey,
leading to assertions. Instead, check if it is our sentinel value
before trying to look into the DenseMap.
This fixes PR26073.
llvm-svn: 257182
Windows EH keeping track of which frame index corresponds to a catchpad
in order to inform the runtime where the catch parameter should be
initialized. LLVM's optimizations are able to prove that the memory
used by the catch parameter can be reused with another memory
optimization, changing it's frame index.
We need to keep WinEHFuncInfo up to date with respect to this or we will
miscompile/assert.
This fixes PR26069.
llvm-svn: 257158
David Majnemer