Fix generated debug info for decls with no location (which include self/_cmd

in ObjC) to not emit file/line location information.  Previously
we would output a file with bogus line information.  This fixes:
rdar://6852814 - Clang generates incorrect file & line info for automatic/understood formal parameters for objc-programs


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70965 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDebugInfo.cpp

@@ -734,17 +734,23 @@ void CGDebugInfo::EmitDeclare(const VarDecl *Decl, unsigned Tag,
   if (CO.OptimizationLevel)
     return;
 
+  llvm::DICompileUnit Unit = getOrCreateCompileUnit(Decl->getLocation());
+  llvm::DIType Ty = getOrCreateType(Decl->getType(), Unit);
+
   // Get location information.
   SourceManager &SM = M->getContext().getSourceManager();
   PresumedLoc PLoc = SM.getPresumedLoc(Decl->getLocation());
-  unsigned Line = PLoc.isInvalid() ? 0 : PLoc.getLine();
-  llvm::DICompileUnit Unit = getOrCreateCompileUnit(Decl->getLocation());
+  unsigned Line = 0;
+  if (!PLoc.isInvalid())
+    Line = PLoc.getLine();
+  else
+    Unit = llvm::DICompileUnit();
+
   
   // Create the descriptor for the variable.
   llvm::DIVariable D = 
     DebugFactory.CreateVariable(Tag, RegionStack.back(),Decl->getNameAsString(),
-                                Unit, Line,
-                                getOrCreateType(Decl->getType(), Unit));
+                                Unit, Line, Ty);
   // Insert an llvm.dbg.declare into the current block.
   DebugFactory.InsertDeclare(Storage, D, Builder.GetInsertBlock());
 }