[SYCL][Clang] Add sentinel value to kernel_args_sizes (#20540)

Add sentinel value to compiler generated array kernel_args_sizes in
integration header to avoid warnings about empty arrays. This array is
used to hold the number of elements in each kernel. This PR changes the
type to int to add a sentinel value of
std::numeric_limits<uint32_t>::max().

Author: elizabethandrews

clang/lib/Sema/SemaSYCL.cpp

@@ -7056,7 +7056,11 @@ void SYCLIntegrationHeader::emit(raw_ostream &O) {
   for (unsigned I = 0; I < KernelDescs.size(); I++) {
     O << KernelDescs[I].Params.size() << ", ";
   }
+  // Add a sentinel to avoid warning if the collection is empty
+  // (similar to what we do for kernel_signatures below).
+  O << std::numeric_limits<uint32_t>::max() << ", \n";
   O << "};\n\n";
+
   O << "// array representing signatures of all kernels defined in the\n";
   O << "// corresponding source\n";
   O << "static constexpr\n";

clang/test/CodeGenSYCL/int-header-empty-signatures.cpp

@@ -10,7 +10,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {0, 4294967295
 
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {

clang/test/CodeGenSYCL/integration_header.cpp

@@ -25,7 +25,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 //
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {5, 3, 2, 8, 3, 0, 4294967295,
 //
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {

clang/test/CodeGenSYCL/kernel-param-acc-array-ih.cpp

@@ -18,7 +18,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {2, 4294967295,
 
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {

clang/test/CodeGenSYCL/kernel-param-member-acc-array-ih.cpp

@@ -18,7 +18,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {2, 4294967295,
 
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {

clang/test/CodeGenSYCL/kernel-param-pod-array-ih.cpp

@@ -19,7 +19,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {1, 1, 1, 4294967295,
 
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {

clang/test/CodeGenSYCL/union-kernel-param-ih.cpp

@@ -18,7 +18,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {1, 4294967295,
 
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {

clang/test/CodeGenSYCL/wrapped-accessor.cpp

@@ -15,7 +15,7 @@
 // CHECK-NEXT:   ""
 // CHECK-NEXT: };
 
-// CHECK: static constexpr unsigned kernel_args_sizes[] = {
+// CHECK: static constexpr unsigned kernel_args_sizes[] = {1, 4294967295,
 
 // CHECK: static constexpr
 // CHECK-NEXT: const kernel_param_desc_t kernel_signatures[] = {