MI Sched: Update the way resources are tracked so the current heuristics make more sense.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186632 91177308-0d34-0410-b5e6-96231b3b80d8
Debug Info: enable verifying by default and disable testing cases that fail.

1> Use DebugInfoFinder to find debug info MDNodes.
2> Add disable-debug-info-verifier to disable verifying debug info.
3> Disable verifying for testing cases that fail (will update the testing cases
   later on).
4> MDNodes generated by clang can have empty filename for TAG_inheritance and
   TAG_friend, so DIType::Verify is modified accordingly.

Note that DebugInfoFinder does not list all debug info MDNode.
For example, clang can generate:
metadata !{i32 786468}, which will fail to verify.
This MDNode is used by debug info but not included in DebugInfoFinder.
This MDNode is generated as a temporary node in DIBuilder::createFunction
  Value *TElts[] = { GetTagConstant(VMContext, DW_TAG_base_type) };
  MDNode::getTemporary(VMContext, TElts)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186634 91177308-0d34-0410-b5e6-96231b3b80d8
MI Sched: test case fix for previous checkin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186635 91177308-0d34-0410-b5e6-96231b3b80d8
Clarify comment for extension().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186636 91177308-0d34-0410-b5e6-96231b3b80d8
Remove DIBuilder cache of variable TheCU and change the few
uses that wanted it. Also change the interface for createCompileUnit
to compensate. Fix comments that refer to TheCU as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186637 91177308-0d34-0410-b5e6-96231b3b80d8