it more generally available.
Add checks to UnwindAssembly_x86::AugmentUnwindPlanFromCallSite() so
that it won't try to augment an UnwindPlan that already describes
the function epilogue.
Add a test case for backtracing out of _sigtramp on Darwin systems.
This could probably be adapted to test the same thing on linux/bsd but
the function names of sigtramp and kill are probably platform
specific and I'm not sure what they should be.
llvm-svn: 225578
a05677126d