[OpenCL] Restrict pointer to member functions

[Anastasia]

Summary

OpenCL doesn't allow function pointers and therefore pointers to member functions are to be restricted too.

Even if this C++ feature provides more insight of the function that might be pointed too it inherited the same fundamental issue - can lead to the divergent execution of big fragments of code that are very inefficient.

[mantognini]

lgtm, thanks

clang/lib/Sema/SemaDecl.cpp

if (R->isReserveIDT() || R->isClkEventT() || R->isEventT()) {
           << R;
       D.setInvalidType();
       return false;
     }
   }
 
   // OpenCL v1.0 s6.8.a.3: Pointers to functions are not allowed.
   QualType NR = R;
-  while (NR->isPointerType()) {
-    if (NR->isFunctionPointerType()) {
+  while (NR->isPointerType() || NR->isMemberFunctionPointerType()) {
+    if (NR->isFunctionPointerType() || NR->isMemberFunctionPointerType()) {
       Se.Diag(D.getIdentifierLoc(), diag::err_opencl_function_pointer);
       D.setInvalidType();
       return false;
     }
     NR = NR->getPointeeType();
   }
 
   if (!Se.getOpenCLOptions().isEnabled("cl_khr_fp16")) {

clang/test/SemaOpenCLCXX/members.cl

+//RUN: %clang_cc1 %s -triple spir -cl-std=clc++ -verify -fsyntax-only
+
+// Check that pointer to member functions are diagnosed
+struct C {
+  void f(int n);
+};
+
+typedef void (C::*p_t)(int);
+
+template <class T> struct remove_reference { typedef T type; };
+template <class T> struct remove_reference<T &> { typedef T type; };
+
+template <typename T>
+void templ_test() {
+  typename remove_reference<T>::type *ptr; //expected-error{{pointers to functions are not allowed}}
+}
+
+void test() {
+  void (C::*p)(int);       //expected-error{{pointers to functions are not allowed}}
+  p_t p1;                  //expected-error{{pointers to functions are not allowed}}
+  templ_test<int (&)()>(); //expected-note{{in instantiation of function template specialization}}
+}