[OpenCL] Reject virtual functions for OpenCL C++

[svenvh]

Summary

The OpenCL C++ specification doesn't mention restricting virtual inheritance, so leaving that unaffected for now.

[yaxunl]

test/Parser/opencl-cxx-virtual.cl

2

can you add a test for template class with virtual member?

[svenvh]

Added a template class test as requested.

[yaxunl]

LGTM. Thanks!

include/clang/Basic/DiagnosticParseKinds.td

def warn_pragma_extension_is_core : Warning<
   "OpenCL extension %0 is core feature or supported optional core feature - ignoring">, InGroup<DiagGroup<"pedantic-core-features">>, DefaultIgnore;
 
 // OpenCL errors.
 def err_opencl_taking_function_address_parser : Error<
   "taking address of function is not allowed">;
 def err_opencl_logical_exclusive_or : Error<
   "^^ is a reserved operator in OpenCL">;
 
+// OpenCL C++.
+def err_openclcxx_virtual_function : Error<
+  "virtual functions are not supported in OpenCL C++">;
+
 // OpenMP support.
 def warn_pragma_omp_ignored : Warning<
   "unexpected '#pragma omp ...' in program">, InGroup<SourceUsesOpenMP>, DefaultIgnore;
 def warn_omp_extra_tokens_at_eol : Warning<
   "extra tokens at the end of '#pragma omp %0' are ignored">,
   InGroup<ExtraTokens>;
 def warn_pragma_expected_colon_r_paren : Warning<
   "missing ':' or ')' after %0 - ignoring">, InGroup<IgnoredPragmas>;

include/clang/Basic/LangOptions.def

 LANGOPT(WCharIsSigned        , 1, 0, "signed or unsigned wchar_t")
 ENUM_LANGOPT(MSPointerToMemberRepresentationMethod, PragmaMSPointersToMembersKind, 2, PPTMK_BestCase, "member-pointer representation method")
 ENUM_LANGOPT(DefaultCallingConv, DefaultCallingConvention, 3, DCC_None, "default calling convention")
 
 LANGOPT(ShortEnums        , 1, 0, "short enum types")
 
 LANGOPT(OpenCL            , 1, 0, "OpenCL")
 LANGOPT(OpenCLVersion     , 32, 0, "OpenCL C version")
+LANGOPT(OpenCLCPlusPlus   , 1, 0, "OpenCL C++")
 LANGOPT(OpenCLCPlusPlusVersion     , 32, 0, "OpenCL C++ version")
 LANGOPT(NativeHalfType    , 1, 0, "Native half type support")
 LANGOPT(NativeHalfArgsAndReturns, 1, 0, "Native half args and returns")
 LANGOPT(HalfArgsAndReturns, 1, 0, "half args and returns")
 LANGOPT(CUDA              , 1, 0, "CUDA")
 LANGOPT(OpenMP            , 32, 0, "OpenMP support and version of OpenMP (31, 40 or 45)")
 LANGOPT(OpenMPSimd        , 1, 0, "Use SIMD only OpenMP support.")
 LANGOPT(OpenMPUseTLS      , 1, 0, "Use TLS for threadprivates or runtime calls")

lib/Frontend/CompilerInvocation.cpp

#endif
   // OpenCL has some additional defaults.
   if (Opts.OpenCL) {
     Opts.AltiVec = 0;
     Opts.ZVector = 0;
     Opts.LaxVectorConversions = 0;
     Opts.setDefaultFPContractMode(LangOptions::FPC_On);
     Opts.NativeHalfType = 1;
     Opts.NativeHalfArgsAndReturns = 1;
+    Opts.OpenCLCPlusPlus = Opts.CPlusPlus;
     // Include default header file for OpenCL.
     if (Opts.IncludeDefaultHeader) {
       PPOpts.Includes.push_back("opencl-c.h");
     }
   }
 
   Opts.CUDA = IK.getLanguage() == InputKind::CUDA;
   if (Opts.CUDA)

lib/Parse/ParseDecl.cpp

case tok::kw__Thread_local:
       isStorageClass = true;
       break;
 
     // function-specifier
     case tok::kw_inline:
       isInvalid = DS.setFunctionSpecInline(Loc, PrevSpec, DiagID);
       break;
     case tok::kw_virtual:
+      // OpenCL C++ v1.0 s2.9: the virtual function qualifier is not supported.
+      if (getLangOpts().OpenCLCPlusPlus) {
+        DiagID = diag::err_openclcxx_virtual_function;
+        PrevSpec = Tok.getIdentifierInfo()->getNameStart();
+        isInvalid = true;
+      }
+      else {
         isInvalid = DS.setFunctionSpecVirtual(Loc, PrevSpec, DiagID);
+      }
       break;
     case tok::kw_explicit:
       isInvalid = DS.setFunctionSpecExplicit(Loc, PrevSpec, DiagID);
       break;
     case tok::kw__Noreturn:
       if (!getLangOpts().C11)
         Diag(Loc, diag::ext_c11_noreturn);
       isInvalid = DS.setFunctionSpecNoreturn(Loc, PrevSpec, DiagID);

test/Parser/opencl-cxx-virtual.cl

+// RUN: %clang_cc1 %s -triple spir-unknown-unknown -cl-std=c++ -fsyntax-only -verify
+
+// Test that virtual functions and abstract classes are rejected.
+class virtual_functions {
+  virtual void bad1() {}
+  //expected-error@-1 {{virtual functions are not supported in OpenCL C++}}
+
+  virtual void bad2() =0;
+  //expected-error@-1 {{virtual functions are not supported in OpenCL C++}}
+  //expected-error@-2 {{'bad2' is not virtual and cannot be declared pure}}
+};
+
+template <typename T>
+class X {
+  virtual T f();
+  //expected-error@-1 {{virtual functions are not supported in OpenCL C++}}
+};
+
+// Test that virtual base classes are allowed.
+struct A {
+  int a;
+  void foo();
+};
+
+struct B : virtual A {
+  int b;
+};
+
+struct C : public virtual A {
+  int c;
+};
+
+struct D : B, C {
+  int d;
+};
+
+kernel void virtual_inheritance() {
+  D d;
+
+  d.foo();
+  d.a = 11;
+  d.b = 22;
+  d.c = 33;
+  d.d = 44;
+}