[OPENMP] Fix for checking of data-sharing attributes for canonical var decls only.

Currently checks for active data-sharing attributes for variables are performed for found var decls. Instead these checks must be performed for canonical decls of these variables to avoid possible troubles with with the differently qualified re-declarations of the same variable, for example:
namespace A { int x; }
namespace B { using A::x; }
Both A::x and B::x actually reference the same object A::x and this fact must be taken into account during data-sharing attributes analysis.

llvm-svn: 235096
diff --git a/clang/test/OpenMP/parallel_sections_firstprivate_messages.cpp b/clang/test/OpenMP/parallel_sections_firstprivate_messages.cpp
index 2d27b1a..23ae128 100644
--- a/clang/test/OpenMP/parallel_sections_firstprivate_messages.cpp
+++ b/clang/test/OpenMP/parallel_sections_firstprivate_messages.cpp
@@ -155,6 +155,14 @@
   return 0;
 }
 
+namespace A {
+double x;
+#pragma omp threadprivate(x) // expected-note {{defined as threadprivate or thread local}}
+}
+namespace B {
+using A::x;
+}
+
 int main(int argc, char **argv) {
   const int d = 5;
   const int da[5] = {0};
@@ -245,7 +253,7 @@
   {
     foo();
   }
-#pragma omp parallel sections firstprivate(h) // expected-error {{threadprivate or thread local variable cannot be firstprivate}}
+#pragma omp parallel sections firstprivate(h, B::x) // expected-error 2 {{threadprivate or thread local variable cannot be firstprivate}}
   {
     foo();
   }