Reapply 79977.

Use MDNodes to encode debug info in llvm IR.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80406 91177308-0d34-0410-b5e6-96231b3b80d8

test/FrontendObjC/2009-02-17-RunTimeVer-dbg.m

@@ -1,13 +0,0 @@
-// RUN: %llvmgcc -x objective-c -S %s -g --emit-llvm -o - | grep "dbg.compile_unit =" | grep "null, i32"
-// Last parameter represent i32 runtime version id. The previous paramenter
-// encodes command line flags when certain env. variables are set. In this
-// example it is the only compile_unit parameter that is null. This test case
-// tests existence of new additional compile_unit parameter to encode 
-// Objective-C runtime version number.
-
-@interface foo
-@end
-@implementation foo
-@end
-
-void fn(foo *f) {}