From c4fa8b867e700a46534028e61a9e8ff90c51678e Mon Sep 17 00:00:00 2001
From: Jinxin Yang <jinxiny@nvidia.com>
Date: Wed, 4 Sep 2019 23:35:44 -0700
Subject: [PATCH] [flang] [OpenMP] Add structural checks for `TASK`

1. fix `OmpIfClause` on `Task`
2. add structural checks

Original-commit: flang-compiler/f18@a77830a191989d7885337cf6182ac82ccf9c5ae9
---
 flang/lib/parser/openmp-grammar.h             |  4 +--
 flang/lib/semantics/check-omp-structure.cc    | 26 ++++++++++++++++--
 .../test/semantics/omp-clause-validity01.f90  | 27 ++++++++++++++++++-
 3 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/flang/lib/parser/openmp-grammar.h b/flang/lib/parser/openmp-grammar.h
index 6408e49c2974..ab6b338864bb 100644
--- a/flang/lib/parser/openmp-grammar.h
+++ b/flang/lib/parser/openmp-grammar.h
@@ -107,8 +107,8 @@ TYPE_PARSER(construct<OmpIfClause>(
               "TARGET UPDATE" >>
                   pure(OmpIfClause::DirectiveNameModifier::TargetUpdate) ||
               "TARGET" >> pure(OmpIfClause::DirectiveNameModifier::Target) ||
-              "TASK"_id >> pure(OmpIfClause::DirectiveNameModifier::Taskloop) ||
-              "TASKLOOP" >> pure(OmpIfClause::DirectiveNameModifier::Task)) /
+              "TASK"_id >> pure(OmpIfClause::DirectiveNameModifier::Task) ||
+              "TASKLOOP" >> pure(OmpIfClause::DirectiveNameModifier::Taskloop)) /
         ":"),
     scalarLogicalExpr))
 
diff --git a/flang/lib/semantics/check-omp-structure.cc b/flang/lib/semantics/check-omp-structure.cc
index 795dfcedcdad..91c968dbf005 100644
--- a/flang/lib/semantics/check-omp-structure.cc
+++ b/flang/lib/semantics/check-omp-structure.cc
@@ -97,7 +97,8 @@ void OmpStructureChecker::CheckAllowed(OmpClause type) {
     });
     for (const auto &e : others) {
       context_.Say(GetContext().clauseSource,
-          "%s and %s are mutually exclusive and may not appear on the same %s directive"_err_en_US,
+          "%s and %s are mutually exclusive and may not appear on the "
+          "same %s directive"_err_en_US,
           EnumToString(type), EnumToString(e),
           parser::ToUpperCaseLetters(GetContext().directiveSource.ToString()));
     }
@@ -326,6 +327,26 @@ void OmpStructureChecker::Enter(const parser::OpenMPBlockConstruct &x) {
   case parser::OmpBlockDirective::Directive::Workshare:
     PushContext(beginDir.source, OmpDirective::WORKSHARE);
     break;
+    // 2.9.1 task-clause -> if-clause |
+    //                      final-clause |
+    //                      untied-clause |
+    //                      default-clause |
+    //                      mergeable-clause |
+    //                      private-clause |
+    //                      firstprivate-clause |
+    //                      shared-clause |
+    //                      depend-clause |
+    //                      priority-clause
+  case parser::OmpBlockDirective::Directive::Task: {
+    PushContext(beginDir.source, OmpDirective::TASK);
+    OmpClauseSet allowed{OmpClause::UNTIED, OmpClause::DEFAULT,
+        OmpClause::MERGEABLE, OmpClause::PRIVATE, OmpClause::FIRSTPRIVATE,
+        OmpClause::SHARED, OmpClause::DEPEND};
+    SetContextAllowed(allowed);
+    OmpClauseSet allowedOnce{
+        OmpClause::IF, OmpClause::FINAL, OmpClause::PRIORITY};
+    SetContextAllowedOnce(allowedOnce);
+  } break;
   default:
     // TODO others
     break;
@@ -695,8 +716,9 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Ordered &x) {
     }
   }
 }
-void OmpStructureChecker::Enter(const parser::OmpClause::Priority &) {
+void OmpStructureChecker::Enter(const parser::OmpClause::Priority &x) {
   CheckAllowed(OmpClause::PRIORITY);
+  RequiresPositiveParameter(OmpClause::PRIORITY, x.v);
 }
 void OmpStructureChecker::Enter(const parser::OmpClause::Private &) {
   CheckAllowed(OmpClause::PRIVATE);
diff --git a/flang/test/semantics/omp-clause-validity01.f90 b/flang/test/semantics/omp-clause-validity01.f90
index 1ca70e7822e4..04d008ba1d75 100644
--- a/flang/test/semantics/omp-clause-validity01.f90
+++ b/flang/test/semantics/omp-clause-validity01.f90
@@ -376,7 +376,6 @@
     a = 3.14
   enddo
 
-
 ! Standalone Directives (basic)
 
   !$omp taskyield
@@ -399,4 +398,30 @@
   a = 3.14
   !ERROR: Internal: no symbol found for 'first'
   !$omp end critical (first)
+
+! 2.9.1 task-clause -> if-clause |
+!                      final-clause |
+!                      untied-clause |
+!                      default-clause |
+!                      mergeable-clause |
+!                      private-clause |
+!                      firstprivate-clause |
+!                      shared-clause |
+!                      depend-clause |
+!                      priority-clause
+
+  !$omp task shared(a) default(none) if(task:a > 1.)
+  a = 1.
+  !$omp end task
+
+  !ERROR: LASTPRIVATE clause is not allowed on the TASK directive
+  !ERROR: At most one FINAL clause can appear on the TASK directive
+  !$omp task lastprivate(b) final(a.GE.1) final(.false.)
+  b = 1
+  !$omp end task
+
+  !ERROR: The parameter of the PRIORITY clause must be a positive integer expression
+  !$omp task priority(-1) firstprivate(a) mergeable
+  a = 3.14
+  !$omp end task
 end program