Eliminate an assortment of undefined behavior.

Hopefully, this fixes the PPC64 buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185218 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused member

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185219 91177308-0d34-0410-b5e6-96231b3b80d8
Revising the MCJIT ObjectCache interface to allow subclasses to avoid retaining references to returned objects

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185221 91177308-0d34-0410-b5e6-96231b3b80d8
Fix Windows/Darwin build error in DebugIR unit tests
- mistakenly used get_current_dir() linux function
- replaced with getcwd/_getcwd as appropriate for current platform



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185225 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a bad overflow check pointed out by Ben.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185226 91177308-0d34-0410-b5e6-96231b3b80d8
Fix broken asserts that never fire.

Change assert("text") to assert(0 && "text").  The first case is a const char *
to bool conversion, which always evaluates to true, never triggering the
assert.  The second case will always trigger the assert.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185227 91177308-0d34-0410-b5e6-96231b3b80d8