[SYCL] Error for implicit capture of this pointer inside a sycl kernel (#2029)

Signed-off-by: Arvind Sudarsanam <[email protected]>

Author: asudarsa

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -7326,6 +7326,8 @@ let CategoryName = "Lambda Issue" in {
     "here">;
   def note_var_explicitly_captured_here : Note<"variable %0 is"
     "%select{| explicitly}1 captured here">;
+  def err_implicit_this_capture : Error<
+    "implicit capture of 'this' is not allowed for kernel functions">;
 
   // C++14 lambda init-captures.
   def warn_cxx11_compat_init_capture : Warning<

clang/lib/Sema/SemaSYCL.cpp

@@ -1944,6 +1944,11 @@ void Sema::ConstructOpenCLKernel(FunctionDecl *KernelCallerFunc,
       constructKernelName(*this, KernelCallerFunc, MC);
   StringRef KernelName(getLangOpts().SYCLUnnamedLambda ? StableName
                                                        : CalculatedName);
+  if (KernelObj->isLambda()) {
+    for (const LambdaCapture &LC : KernelObj->captures())
+      if (LC.capturesThis() && LC.isImplicit())
+        Diag(LC.getLocation(), diag::err_implicit_this_capture);
+  }
   SyclKernelFieldChecker checker(*this);
   SyclKernelDeclCreator kernel_decl(
       *this, checker, KernelName, KernelObj->getLocation(),

clang/test/SemaSYCL/lambda_implicit_capture_this.cpp

@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -I %S/Inputs -fsycl -fsycl-is-device -fsyntax-only -verify %s
+
+template <typename name, typename Func>
+__attribute__((sycl_kernel)) void kernel(Func kernelFunc) {
+  kernelFunc();
+}
+
+class Class {
+public:
+  Class() : member(1) {}
+  void function();
+  int member;
+};
+
+void Class::function() {
+  kernel<class kernel_wrapper>(
+      [=]() {
+        int acc[1] = {5};
+        acc[0] *= member; // expected-error{{implicit capture of 'this' is not allowed for kernel functions}}
+      });
+}
+
+int main(int argc, char *argv[]) {
+  Class c;
+  c.function();
+}

sycl/include/CL/sycl/handler.hpp

@@ -509,8 +509,8 @@ class __SYCL_EXPORT handler {
 
   template <typename T, int Dim, access::mode Mode, access::target Target,
             access::placeholder IsPH>
-  detail::enable_if_t<Dim == 0 && Mode == access::mode::atomic, T>
-  readFromFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Src) const {
+  static detail::enable_if_t<Dim == 0 && Mode == access::mode::atomic, T>
+  readFromFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Src) {
 #ifdef __ENABLE_USM_ADDR_SPACE__
     atomic<T, access::address_space::global_device_space> AtomicSrc = Src;
 #else
@@ -521,23 +521,23 @@ class __SYCL_EXPORT handler {
 
   template <typename T, int Dim, access::mode Mode, access::target Target,
             access::placeholder IsPH>
-  detail::enable_if_t<(Dim > 0) && Mode == access::mode::atomic, T>
-  readFromFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Src) const {
+  static detail::enable_if_t<(Dim > 0) && Mode == access::mode::atomic, T>
+  readFromFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Src) {
     id<Dim> Id = getDelinearizedIndex(Src.get_range(), 0);
     return Src[Id].load();
   }
 
   template <typename T, int Dim, access::mode Mode, access::target Target,
             access::placeholder IsPH>
-  detail::enable_if_t<Mode != access::mode::atomic, T>
-  readFromFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Src) const {
+  static detail::enable_if_t<Mode != access::mode::atomic, T>
+  readFromFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Src) {
     return *(Src.get_pointer());
   }
 
   template <typename T, int Dim, access::mode Mode, access::target Target,
             access::placeholder IsPH>
-  detail::enable_if_t<Dim == 0 && Mode == access::mode::atomic, void>
-  writeToFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Dst, T V) const {
+  static detail::enable_if_t<Dim == 0 && Mode == access::mode::atomic, void>
+  writeToFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Dst, T V) {
 #ifdef __ENABLE_USM_ADDR_SPACE__
     atomic<T, access::address_space::global_device_space> AtomicDst = Dst;
 #else
@@ -548,16 +548,16 @@ class __SYCL_EXPORT handler {
 
   template <typename T, int Dim, access::mode Mode, access::target Target,
             access::placeholder IsPH>
-  detail::enable_if_t<(Dim > 0) && Mode == access::mode::atomic, void>
-  writeToFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Dst, T V) const {
+  static detail::enable_if_t<(Dim > 0) && Mode == access::mode::atomic, void>
+  writeToFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Dst, T V) {
     id<Dim> Id = getDelinearizedIndex(Dst.get_range(), 0);
     Dst[Id].store(V);
   }
 
   template <typename T, int Dim, access::mode Mode, access::target Target,
             access::placeholder IsPH>
-  detail::enable_if_t<Mode != access::mode::atomic, void>
-  writeToFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Dst, T V) const {
+  static detail::enable_if_t<Mode != access::mode::atomic, void>
+  writeToFirstAccElement(accessor<T, Dim, Mode, Target, IsPH> Dst, T V) {
     *(Dst.get_pointer()) = V;
   }