Index: include/llvm/IR/DIBuilder.h
===================================================================
--- include/llvm/IR/DIBuilder.h
+++ include/llvm/IR/DIBuilder.h
@@ -87,7 +87,7 @@
     public:
     explicit DIBuilder(Module &M);
     enum ComplexAddrKind { OpPlus=1, OpDeref };
-    enum DebugEmissionKind { FullDebug=1, LineTablesOnly };
+    enum DebugEmissionKind { FullDebug=1, LineTablesOnly, LocTrackingOnly };
 
     /// finalize - Construct any deferred debug info descriptors.
     void finalize();
@@ -108,6 +108,7 @@
     ///                 Objective-C.
     /// @param SplitName The name of the file that we'll split debug info out
     ///                  into.
+    /// @param Kind     The kind of debug information to generate.
     DICompileUnit createCompileUnit(unsigned Lang, StringRef File,
                                     StringRef Dir, StringRef Producer,
                                     bool isOptimized, StringRef Flags,
Index: lib/IR/DIBuilder.cpp
===================================================================
--- lib/IR/DIBuilder.cpp
+++ lib/IR/DIBuilder.cpp
@@ -140,8 +140,14 @@
   MDNode *CUNode = MDNode::get(VMContext, Elts);
 
   // Create a named metadata so that it is easier to find cu in a module.
-  NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
-  NMD->addOperand(CUNode);
+  // Note that we only generate this when the caller wants to actually
+  // emit debug information. When we are only interested in tracking
+  // source line locations throughout the backend, we prevent codegen from
+  // emitting debug info in the final output by not generating llvm.dbg.cu.
+  if (Kind != LocTrackingOnly) {
+    NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
+    NMD->addOperand(CUNode);
+  }
 
   return DICompileUnit(CUNode);
 }