Fix coverage for files with global constructors again. Adds a testcase to the commit from r206671, as requested by David Blaikie.

llvm-svn: 210239
diff --git a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index 583a094..cfeb62e 100644
--- a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -457,8 +457,13 @@
       // Debug intrinsic locations correspond to the location of the
       // declaration, not necessarily any statements or expressions.
       if (isa<DbgInfoIntrinsic>(I)) continue;
+
       const DebugLoc &Loc = I->getDebugLoc();
       if (Loc.isUnknown()) continue;
+
+      // Artificial lines such as calls to the global constructors.
+      if (Loc.getLine() == 0) continue; 
+
       return true;
     }
   }
@@ -521,8 +526,13 @@
           // Debug intrinsic locations correspond to the location of the
           // declaration, not necessarily any statements or expressions.
           if (isa<DbgInfoIntrinsic>(I)) continue;
+
           const DebugLoc &Loc = I->getDebugLoc();
           if (Loc.isUnknown()) continue;
+
+          // Artificial lines such as calls to the global constructors.
+          if (Loc.getLine() == 0) continue;
+
           if (Line == Loc.getLine()) continue;
           Line = Loc.getLine();
           if (SP != getDISubprogram(Loc.getScope(*Ctx))) continue;