CodeGen: assert an instruction is being inserted with the correct iterator.

When "MBB->Insert(It, ...)" is called, we want It to be pointing inside the
correct basic block. No actual failures at the moment, but it's caused problems
before.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221953 91177308-0d34-0410-b5e6-96231b3b80d8
Allow the use of functions as typeinfo in landingpad clauses

This is one step towards supporting SEH filter functions in LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221954 91177308-0d34-0410-b5e6-96231b3b80d8
Fix build of Mips code with MSVC by using our macro instead of __attribute__((unused)) directly

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221956 91177308-0d34-0410-b5e6-96231b3b80d8
Fix 80 cols caught by the linter...

We have a linter running in our build now?

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221957 91177308-0d34-0410-b5e6-96231b3b80d8
StringMap: Test and finish off supporting perfectly forwarded values in StringMap operations.

Followup to r221946.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221958 91177308-0d34-0410-b5e6-96231b3b80d8
IR: Rewrite uniquing and creation of MDString

Stop using `Value::getName()` to get the string behind an `MDString`.
Switch to `StringMapEntry<MDString>` so that we can find the string by
its coallocation.

This is part of PR21532.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221960 91177308-0d34-0410-b5e6-96231b3b80d8