[OpenMP] Add nowait clause to the target update pragma (sema and parsing)

[kkwli0]

Summary

This patch is to add the nowait clause to the target update pragma. It is sema and parsing only.

[ABataev]

LG

include/clang/Basic/OpenMPKinds.def

 OPENMP_TARGET_PARALLEL_FOR_CLAUSE(linear)
 
 // Clauses allowed for OpenMP directive 'target update'.
 // TODO More clauses for 'target update' directive.
 OPENMP_TARGET_UPDATE_CLAUSE(if)
 OPENMP_TARGET_UPDATE_CLAUSE(device)
 OPENMP_TARGET_UPDATE_CLAUSE(to)
 OPENMP_TARGET_UPDATE_CLAUSE(from)
+OPENMP_TARGET_UPDATE_CLAUSE(nowait)
 
 // Clauses allowed for OpenMP directive 'teams'.
 // TODO More clauses for 'teams' directive.
 OPENMP_TEAMS_CLAUSE(default)
 OPENMP_TEAMS_CLAUSE(private)
 OPENMP_TEAMS_CLAUSE(firstprivate)
 OPENMP_TEAMS_CLAUSE(shared)
 OPENMP_TEAMS_CLAUSE(reduction)

test/OpenMP/target_update_ast_print.cpp

 // RUN: %clang_cc1 -verify -fopenmp -ast-print %s | FileCheck %s
 // RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -emit-pch -o %t %s
 // RUN: %clang_cc1 -fopenmp -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
 // expected-no-diagnostics
 
 #ifndef HEADER
 #define HEADER
 
 void foo() {}
 
 template <class T, class U>
 T foo(T targ, U uarg) {
   static T a;
   U b;
   int l;
-#pragma omp target update to(a) if(l>5) device(l)
+#pragma omp target update to(a) if(l>5) device(l) nowait
 
-#pragma omp target update from(b) if(l<5) device(l-1)
+#pragma omp target update from(b) if(l<5) device(l-1) nowait
   return a + targ + (T)b;
 }
 // CHECK:      static int a;
 // CHECK-NEXT: float b;
 // CHECK-NEXT: int l;
 // CHECK-NEXT: #pragma omp target update to(a) if(l > 5) device(l)
-// CHECK-NEXT: #pragma omp target update from(b) if(l < 5) device(l - 1)
+// CHECK-NEXT: #pragma omp target update from(b) if(l < 5) device(l - 1) nowait
 // CHECK:      static char a;
 // CHECK-NEXT: float b;
 // CHECK-NEXT: int l;
-// CHECK-NEXT: #pragma omp target update to(a) if(l > 5) device(l)
-// CHECK-NEXT: #pragma omp target update from(b) if(l < 5) device(l - 1)
+// CHECK-NEXT: #pragma omp target update to(a) if(l > 5) device(l) nowait
+// CHECK-NEXT: #pragma omp target update from(b) if(l < 5) device(l - 1) nowait
 // CHECK:      static T a;
 // CHECK-NEXT: U b;
 // CHECK-NEXT: int l;
-// CHECK-NEXT: #pragma omp target update to(a) if(l > 5) device(l)
-// CHECK-NEXT: #pragma omp target update from(b) if(l < 5) device(l - 1)
+// CHECK-NEXT: #pragma omp target update to(a) if(l > 5) device(l) nowait
+// CHECK-NEXT: #pragma omp target update from(b) if(l < 5) device(l - 1) nowait
 
 int main(int argc, char **argv) {
   static int a;
   int n;
   float f;
 
 // CHECK:      static int a;
 // CHECK-NEXT: int n;
 // CHECK-NEXT: float f;
-#pragma omp target update to(a) if(f>0.0) device(n)
-  // CHECK-NEXT: #pragma omp target update to(a) if(f > 0.) device(n)
-#pragma omp target update from(f) if(f<0.0) device(n+1)
-  // CHECK-NEXT: #pragma omp target update from(f) if(f < 0.) device(n + 1)
+#pragma omp target update to(a) if(f>0.0) device(n) nowait
+// CHECK-NEXT: #pragma omp target update to(a) if(f > 0.) device(n) nowait
+#pragma omp target update from(f) if(f<0.0) device(n+1) nowait
+// CHECK-NEXT: #pragma omp target update from(f) if(f < 0.) device(n + 1) nowait
   return foo(argc, f) + foo(argv[0][0], f) + a;
 }
 
 #endif

test/OpenMP/target_update_nowait_messages.cpp

+// RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 %s
+
+int main(int argc, char **argv) {
+  int i;
+
+  #pragma omp nowait target update to(i) // expected-error {{expected an OpenMP directive}}
+  #pragma omp target nowait update to(i) // expected-error {{unexpected OpenMP clause 'update' in directive '#pragma omp target'}} expected-error {{unexpected OpenMP clause 'to' in directive '#pragma omp target'}}
+  {}
+  #pragma omp target update nowait() to(i) // expected-warning {{extra tokens at the end of '#pragma omp target update' are ignored}} expected-error {{expected at least one 'to' clause or 'from' clause specified to '#pragma omp target update'}}
+  #pragma omp target update to(i) nowait( // expected-warning {{extra tokens at the end of '#pragma omp target update' are ignored}}
+  #pragma omp target update to(i) nowait (argc)) // expected-warning {{extra tokens at the end of '#pragma omp target update' are ignored}}
+  #pragma omp target update to(i) nowait device (-10u)
+  #pragma omp target update to(i) nowait (3.14) device (-10u) // expected-warning {{extra tokens at the end of '#pragma omp target update' are ignored}}
+  #pragma omp target update to(i) nowait nowait // expected-error {{directive '#pragma omp target update' cannot contain more than one 'nowait' clause}}
+  #pragma omp target update nowait to(i) nowait // expected-error {{directive '#pragma omp target update' cannot contain more than one 'nowait' clause}}
+  return 0;
+}