[flang-commits] [flang] [flang][OpenMP][#225225] Add diagnosis on invalid list items in depend(depobj:) clauses (PR #227790)

[via flang-commits]

https://github.com/laoshd updated https://github.com/llvm/llvm-project/pull/227790

>From c5efbb428dd8ad5c165eb496f6929ea4ddcf9e5f Mon Sep 17 00:00:00 2001
From: Shandong Lao <shandong.lao at hpe.com>
Date: Wed, 30 Sep 2026 05:43:45 -0500
Subject: [PATCH] [FLANG][OpenMP] Implement DEPOBJ dependence type checks in
 OmpStructureChecker and add related tests.

---
 flang/lib/Semantics/check-omp-structure.cpp   | 48 +++++++++++++++++--
 .../OpenMP/Todo/depend-clause-depobj.f90      |  3 +-
 flang/test/Semantics/OpenMP/depend-depobj.f90 | 35 ++++++++++++++
 3 files changed, 81 insertions(+), 5 deletions(-)
 create mode 100644 flang/test/Semantics/OpenMP/depend-depobj.f90

diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 09b6c6bc3449fb..65ff3849000296 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -5257,6 +5257,42 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Depend &x) {
             "one locator"_err_en_US);
       }
     }
+    // [5.0:256:1-2], [5.1:288:19-20], [5.2:323:1-2]
+    // With the DEPOBJ dependence type, array sections cannot be specified and
+    // the list items must be depend objects (scalar integer variables of kind
+    // omp_depend_kind, which is c_intptr_t). This does not apply on the DEPOBJ
+    // construct itself, where the DEPOBJ dependence type is already disallowed.
+    bool isDepobjType{dir != llvm::omp::OMPD_depobj &&
+        taskDep->GetTaskDepType() ==
+            parser::OmpTaskDependenceType::Value::Depobj};
+    auto checkDepobjVar = [&](const parser::OmpObject &object) {
+      const parser::Designator *designator{GetDesignatorFromObj(object)};
+      if (!designator) {
+        context_.Say(GetContext().clauseSource,
+            "A list item in a DEPEND clause with the DEPOBJ dependence type must be a depend object"_err_en_US);
+        return;
+      }
+      evaluate::ExpressionAnalyzer ea{context_};
+      auto restore{ea.AllowWholeAssumedSizeArray(true)};
+      MaybeExpr expr{ea.Analyze(*designator)};
+      if (!expr) {
+        return;
+      }
+      if (expr->Rank() != 0) {
+        context_.Say(GetContext().clauseSource,
+            "Array sections cannot be specified in a DEPEND clause with the DEPOBJ dependence type"_err_en_US);
+        return;
+      }
+      // A depend object is a scalar integer of omp_depend_kind (c_intptr_t).
+      std::optional<evaluate::DynamicType> type{expr->GetType()};
+      int depobjKind{static_cast<int>(
+          context_.targetCharacteristics().integerKindForPointer())};
+      if (!type || type->category() != evaluate::TypeCategory::Integer ||
+          type->kind() != depobjKind) {
+        context_.Say(GetContext().clauseSource,
+            "A list item in a DEPEND clause with the DEPOBJ dependence type must be a depend object (a scalar integer variable of kind omp_depend_kind)"_err_en_US);
+      }
+    };
     for (const auto &object : objList.v) {
       if (const auto *name{GetCommonBlockFromObj(object)}) {
         context_.Say(GetContext().clauseSource,
@@ -5264,10 +5300,14 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Depend &x) {
             "clause"_err_en_US,
             name->ToString());
       } else if (auto *dataRef{GetDataRefFromObj(object)}) {
-        CheckDependList(*dataRef);
-        if (const auto *arr{GetArrayElementFromObj(object)}) {
-          CheckArraySection(
-              *arr, GetLastName(*dataRef), llvm::omp::Clause::OMPC_depend);
+        if (isDepobjType) {
+          checkDepobjVar(object);
+        } else {
+          CheckDependList(*dataRef);
+          if (const auto *arr{GetArrayElementFromObj(object)}) {
+            CheckArraySection(
+                *arr, GetLastName(*dataRef), llvm::omp::Clause::OMPC_depend);
+          }
         }
       }
     }
diff --git a/flang/test/Lower/OpenMP/Todo/depend-clause-depobj.f90 b/flang/test/Lower/OpenMP/Todo/depend-clause-depobj.f90
index 4e98d77d0bb3e3..aecdde4ca48204 100644
--- a/flang/test/Lower/OpenMP/Todo/depend-clause-depobj.f90
+++ b/flang/test/Lower/OpenMP/Todo/depend-clause-depobj.f90
@@ -4,7 +4,8 @@
 !CHECK: not yet implemented: DEPOBJ dependence-type
 
 subroutine f00(x)
-  integer :: x
+  use iso_c_binding, only: c_intptr_t
+  integer(c_intptr_t) :: x
   !$omp task depend(depobj: x)
   !$omp end task
 end
diff --git a/flang/test/Semantics/OpenMP/depend-depobj.f90 b/flang/test/Semantics/OpenMP/depend-depobj.f90
new file mode 100644
index 00000000000000..98944c72f9265b
--- /dev/null
+++ b/flang/test/Semantics/OpenMP/depend-depobj.f90
@@ -0,0 +1,35 @@
+!RUN: %python %S/../test_errors.py %s %flang -fopenmp -fopenmp-version=52
+
+! OpenMP 5.0 2.17.11 depend Clause restrictions for the DEPOBJ dependence type:
+!  - Array sections cannot be specified.
+!  - List items must be depend objects (scalar integers of omp_depend_kind).
+
+subroutine f00(x, y, obj, objs)
+  use iso_c_binding, only: c_intptr_t
+  integer :: x
+  integer :: y(10)
+  integer(c_intptr_t) :: obj
+  integer(c_intptr_t) :: objs(10)
+
+  ! A plain integer is not a depend object (wrong kind).
+  !ERROR: A list item in a DEPEND clause with the DEPOBJ dependence type must be a depend object (a scalar integer variable of kind omp_depend_kind)
+  !$omp task depend(depobj: x)
+  !$omp end task
+
+  ! Array sections cannot be specified.
+  !ERROR: Array sections cannot be specified in a DEPEND clause with the DEPOBJ dependence type
+  !$omp task depend(depobj: objs(1:3))
+  !$omp end task
+
+  ! A whole array is not a depend object.
+  !ERROR: Array sections cannot be specified in a DEPEND clause with the DEPOBJ dependence type
+  !$omp task depend(depobj: y)
+  !$omp end task
+
+  ! A valid depend object (scalar) and a depend-object array element are accepted
+  ! by semantics (lowering is not yet implemented).
+  !$omp task depend(depobj: obj)
+  !$omp end task
+  !$omp task depend(depobj: objs(2))
+  !$omp end task
+end