llvm.dbg.region.end() intrinsic is not required to be in _last_ basic block in a function.  If that happens then any basic block that follows (lexically) the block with regin.end will not have scope info available.  LexicalScopeStack relies on processing basic block in CFG order, but this processing order is not guaranteed. Things get complicated when the optimizer gets a chance to optimizer IR with dbg intrinsics. 
Apply defensive patch to preserve at least one lexical scope till the end of function.

llvm-svn: 73282

llvm-svn: 73244

llvm-svn: 72948

llvm-svn: 72699

llvm-svn: 72604

llvm-svn: 72198

llvm-svn: 72197

llvm-svn: 72196

llvm-svn: 72195

llvm-svn: 72194

llvm-svn: 72193

the 'constract function dbg thingy'. Rename some methods to make them consistent
with the rest of the methods. Move the 'Emit' methods to the end of the file.

llvm-svn: 72192

llvm-svn: 72064

llvm-svn: 72057

function, this could be many, many times. We don't want to re-add variables to
that DIE for each time. We just want to add them once. Check to make sure that
we haven't added them already.

llvm-svn: 72047

Again, no intendtional functionality change.

llvm-svn: 71854