DebugInfo: Gut DISubprogram and DILexicalBlock*

Gut the `DIDescriptor` wrappers around `MDLocalScope` subclasses.  Note
that `DILexicalBlock` wraps `MDLexicalBlockBase`, not `MDLexicalBlock`.

llvm-svn: 234850
diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index a838bda..06d5aed 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -753,7 +753,7 @@
       // Patch the pointer to LLVM function in debug info descriptor.
       auto DI = FunctionDIs.find(&F);
       if (DI != FunctionDIs.end())
-        DI->second.replaceFunction(&F);
+        DI->second->replaceFunction(&F);
 
       UnwrappedFnMap[WrappedFnCst] = &F;
       *i = NewF;