[OpenMP] Diagnose undeclared variables on declare target clause

[kkwli0]

Summary

Clang asserts on any undeclared variables on the to or link clause in the declare target directive. The patch is to properly diagnose the error.

// foo1 and foo2 are not declared
#pragma omp declare target to(foo1)
#pragma omp declare target link(foo2)

The diagnostic messages are:

d1.cpp:3:31: error: use of undeclared identifier 'foo1'
#pragma omp declare target to(foo1)
                              ^
d1.cpp:4:33: error: use of undeclared identifier 'foo2'
#pragma omp declare target link(foo2)
                                ^
2 errors generated.

[ABataev]

I'm unable to reproduce a crash, the test works correctly even without you patch

[kkwli0]

The original case has the variables named "foo1" and foo2". Using "foo1" or "foo2" causes the assert! I update the description.

[kkwli0]

The assert occurs in VarOrFuncDeclFilterCCC::ValidateCandidate when clang::Sema::CorrectTypo is called.

[ABataev]

LG

cfe/trunk/lib/Sema/SemaOpenMP.cpp

 class VarOrFuncDeclFilterCCC : public CorrectionCandidateCallback {
 private:
   Sema &SemaRef;
 
 public:
   explicit VarOrFuncDeclFilterCCC(Sema &S) : SemaRef(S) {}
   bool ValidateCandidate(const TypoCorrection &Candidate) override {
     NamedDecl *ND = Candidate.getCorrectionDecl();
-    if (isa<VarDecl>(ND) || isa<FunctionDecl>(ND)) {
+    if (ND && (isa<VarDecl>(ND) || isa<FunctionDecl>(ND))) {
       return SemaRef.isDeclInScope(ND, SemaRef.getCurLexicalContext(),
                                    SemaRef.getCurScope());
     }
     return false;
   }
 };
 
 } // namespace

cfe/trunk/test/OpenMP/declare_target_messages.cpp

 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -verify -fopenmp -fnoopenmp-use-tls -ferror-limit 100 -o - %s
 
 #pragma omp end declare target // expected-error {{unexpected OpenMP directive '#pragma omp end declare target'}}
 
 int a, b; // expected-warning {{declaration is not declared in any declare target region}}
 __thread int t; // expected-note {{defined as threadprivate or thread local}}
 
 #pragma omp declare target . // expected-error {{expected '(' after 'declare target'}}
 
 #pragma omp declare target
 void f();
 #pragma omp end declare target shared(a) // expected-warning {{extra tokens at the end of '#pragma omp end declare target' are ignored}}
 
 #pragma omp declare target map(a) // expected-error {{unexpected 'map' clause, only 'to' or 'link' clauses expected}}
 
+#pragma omp declare target to(foo1) // expected-error {{use of undeclared identifier 'foo1'}}
+
+#pragma omp declare target link(foo2) // expected-error {{use of undeclared identifier 'foo2'}}
+
 void c(); // expected-warning {{declaration is not declared in any declare target region}}
 
 extern int b;
 
 struct NonT {
   int a;
 };