[flang-commits] [flang] [flang][Semantics][OpenMP] Don't privatise associate names (PR #108856)

[Tom Eccles via flang-commits]

https://github.com/tblah updated https://github.com/llvm/llvm-project/pull/108856

>From 94fb66a3489fb7088f5e46bf5d9c5bb00ed9d1c5 Mon Sep 17 00:00:00 2001
From: Tom Eccles <tom.eccles at arm.com>
Date: Mon, 16 Sep 2024 16:49:02 +0000
Subject: [PATCH 1/2] [flang][Semantics][OpenMP] Don't privatise associate
 names

The associate name preserves the association with the selector
established in the associate statement. Therefore it is incorrect to
change the data-sharing attribute of the name.

Closes #58041
---
 flang/lib/Semantics/resolve-directives.cpp    |  7 ++++
 flang/test/Semantics/OpenMP/private-assoc.f90 | 32 +++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 flang/test/Semantics/OpenMP/private-assoc.f90

diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index 723596ad6ce454..20a9ae895484e0 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -19,6 +19,7 @@
 #include "flang/Parser/parse-tree.h"
 #include "flang/Parser/tools.h"
 #include "flang/Semantics/expression.h"
+#include "flang/Semantics/symbol.h"
 #include "flang/Semantics/tools.h"
 #include <list>
 #include <map>
@@ -2728,6 +2729,12 @@ void OmpAttributeVisitor::CheckObjectInNamelist(
         "Variable '%s' in NAMELIST cannot be in a %s clause"_err_en_US,
         name.ToString(), clauseName.str());
   }
+
+  if (ultimateSymbol.has<AssocEntityDetails>()) {
+    context_.Say(name.source,
+        "Variable '%s' in ASSOCIATE cannot be in a %s clause"_err_en_US,
+        name.ToString(), clauseName.str());
+  }
 }
 
 void OmpAttributeVisitor::CheckSourceLabel(const parser::Label &label) {
diff --git a/flang/test/Semantics/OpenMP/private-assoc.f90 b/flang/test/Semantics/OpenMP/private-assoc.f90
new file mode 100644
index 00000000000000..bf50cd11de1724
--- /dev/null
+++ b/flang/test/Semantics/OpenMP/private-assoc.f90
@@ -0,0 +1,32 @@
+! RUN: %python %S/../test_errors.py %s %flang -fopenmp
+
+! The ASSOCIATE name preserves the association with the selector established
+! in the associate statement. Therefore it is incorrect to change the
+! data-sharing attribute of the name.
+
+subroutine assoc_private(x)
+  integer :: x
+  associate(z => x)
+  !ERROR: Variable 'z' in ASSOCIATE cannot be in a PRIVATE clause
+  !$omp parallel private(z)
+  !$omp end parallel
+  end associate
+end subroutine
+
+subroutine assoc_firstprivate(x)
+  integer :: x
+  associate(z => x)
+  !ERROR: Variable 'z' in ASSOCIATE cannot be in a FIRSTPRIVATE clause
+  !$omp parallel firstprivate(z)
+  !$omp end parallel
+  end associate
+end subroutine
+
+subroutine assoc_lastprivate(x)
+  integer :: x
+  associate(z => x)
+  !ERROR: Variable 'z' in ASSOCIATE cannot be in a LASTPRIVATE clause
+  !$omp parallel sections lastprivate(z)
+  !$omp end parallel sections
+  end associate
+end subroutine

>From 583d69c38a29d5e1f4e7d51b3f03952b525180e7 Mon Sep 17 00:00:00 2001
From: Tom Eccles <tom.eccles at arm.com>
Date: Tue, 17 Sep 2024 09:44:05 +0000
Subject: [PATCH 2/2] Rename CheckObjectInNamelist

---
 flang/lib/Semantics/resolve-directives.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index 20a9ae895484e0..45fe17c0122c09 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -718,7 +718,7 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
   void CheckDataCopyingClause(
       const parser::Name &, const Symbol &, Symbol::Flag);
   void CheckAssocLoopLevel(std::int64_t level, const parser::OmpClause *clause);
-  void CheckObjectInNamelist(
+  void CheckObjectInNamelistOrAssociate(
       const parser::Name &, const Symbol &, Symbol::Flag);
   void CheckSourceLabel(const parser::Label &);
   void CheckLabelContext(const parser::CharBlock, const parser::CharBlock,
@@ -2357,7 +2357,7 @@ void OmpAttributeVisitor::ResolveOmpObject(
                     CheckMultipleAppearances(*name, *symbol, ompFlag);
                   }
                   if (privateDataSharingAttributeFlags.test(ompFlag)) {
-                    CheckObjectInNamelist(*name, *symbol, ompFlag);
+                    CheckObjectInNamelistOrAssociate(*name, *symbol, ompFlag);
                   }
 
                   if (ompFlag == Symbol::Flag::OmpAllocate) {
@@ -2714,7 +2714,7 @@ void OmpAttributeVisitor::CheckDataCopyingClause(
   }
 }
 
-void OmpAttributeVisitor::CheckObjectInNamelist(
+void OmpAttributeVisitor::CheckObjectInNamelistOrAssociate(
     const parser::Name &name, const Symbol &symbol, Symbol::Flag ompFlag) {
   const auto &ultimateSymbol{symbol.GetUltimate()};
   llvm::StringRef clauseName{"PRIVATE"};