DebugInfo: Metadata constructs now start with DI*

LLVM r236120 renamed debug info IR constructs to use a `DI` prefix, now
that the `DIDescriptor` hierarchy has been gone for about a week.  This
commit was generated using the rename-md-di-nodes.sh upgrade script
attached to PR23080, followed by running clang-format-diff.py on the
`lib/` portion of the patch.

llvm-svn: 236121
diff --git a/clang/test/CodeGenCXX/debug-info-varargs.cpp b/clang/test/CodeGenCXX/debug-info-varargs.cpp
index e51681e..edcb0e5 100644
--- a/clang/test/CodeGenCXX/debug-info-varargs.cpp
+++ b/clang/test/CodeGenCXX/debug-info-varargs.cpp
@@ -2,27 +2,27 @@
 
 struct A
 {
-  // CHECK: !MDSubprogram(name: "a", linkageName: "_ZN1A1aEiz"
+  // CHECK: !DISubprogram(name: "a", linkageName: "_ZN1A1aEiz"
   // CHECK-SAME:          line: [[@LINE+2]]
   // CHECK-SAME:          type: ![[ATY:[0-9]+]]
   void a(int c, ...) {}
-  // CHECK: ![[ATY]] = !MDSubroutineType(types: ![[AARGS:[0-9]+]])
+  // CHECK: ![[ATY]] = !DISubroutineType(types: ![[AARGS:[0-9]+]])
   // We no longer use an explicit unspecified parameter. Instead we use a trailing null to mean the function is variadic.
   // CHECK: ![[AARGS]] = !{null, !{{[0-9]+}}, !{{[0-9]+}}, null}
 };
 
-  // CHECK: !MDSubprogram(name: "b", linkageName: "_Z1biz"
+  // CHECK: !DISubprogram(name: "b", linkageName: "_Z1biz"
   // CHECK-SAME:          line: [[@LINE+2]]
   // CHECK-SAME:          type: ![[BTY:[0-9]+]]
 void b(int c, ...) {
-  // CHECK: ![[BTY]] = !MDSubroutineType(types: ![[BARGS:[0-9]+]])
+  // CHECK: ![[BTY]] = !DISubroutineType(types: ![[BARGS:[0-9]+]])
   // CHECK: ![[BARGS]] = !{null, !{{[0-9]+}}, null}
 
   A a;
 
-  // CHECK: !MDLocalVariable(tag: DW_TAG_auto_variable, name: "fptr"
+  // CHECK: !DILocalVariable(tag: DW_TAG_auto_variable, name: "fptr"
   // CHECK-SAME:             line: [[@LINE+2]]
   // CHECK-SAME:             type: ![[PST:[0-9]+]]
   void (*fptr)(int, ...) = b;
-  // CHECK: ![[PST]] = !MDDerivedType(tag: DW_TAG_pointer_type, baseType: ![[BTY]],
+  // CHECK: ![[PST]] = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: ![[BTY]],
 }