Construct CompileUnits lazily.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91159 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 38bfaf6..0e0064f 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -364,7 +364,7 @@
 
   /// findCompileUnit - Get the compile unit for the given descriptor. 
   ///
-  CompileUnit &findCompileUnit(DICompileUnit Unit) const;
+  CompileUnit *findCompileUnit(DICompileUnit Unit);
 
   /// getUpdatedDbgScope - Find or create DbgScope assicated with 
   /// the instruction. Initialize scope and update scope hierarchy.
@@ -495,7 +495,7 @@
   /// as well.
   unsigned GetOrCreateSourceID(StringRef DirName, StringRef FileName);
 
-  void constructCompileUnit(MDNode *N);
+  CompileUnit *constructCompileUnit(MDNode *N);
 
   void constructGlobalVariableDIE(MDNode *N);