[flang-commits] [flang] a6986f0 - [flang][cuda][openacc] Emit an error when CUDA symbols are imported with CUDA disabled (#205207)

[via flang-commits]

Author: Valentin Clement (バレンタイン クレメン)
Date: 2026-06-22T16:53:26-07:00
New Revision: a6986f0b929d575728d564cd41bb0f9a6b6fdea4

URL: https://github.com/llvm/llvm-project/commit/a6986f0b929d575728d564cd41bb0f9a6b6fdea4
DIFF: https://github.com/llvm/llvm-project/commit/a6986f0b929d575728d564cd41bb0f9a6b6fdea4.diff

LOG: [flang][cuda][openacc] Emit an error when CUDA symbols are imported with CUDA disabled (#205207)

Added: 
    flang/test/Semantics/modfile84.f90

Modified: 
    flang/lib/Semantics/mod-file.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Semantics/mod-file.cpp b/flang/lib/Semantics/mod-file.cpp
index 89a535c6ff6f9..ac44f17009344 100644
--- a/flang/lib/Semantics/mod-file.cpp
+++ b/flang/lib/Semantics/mod-file.cpp
@@ -11,6 +11,7 @@
 #include "flang/Common/restorer.h"
 #include "flang/Evaluate/tools.h"
 #include "flang/Parser/message.h"
+#include "flang/Parser/parse-tree-visitor.h"
 #include "flang/Parser/parsing.h"
 #include "flang/Parser/unparse.h"
 #include "flang/Semantics/scope.h"
@@ -72,6 +73,7 @@ static bool FileContentsMatch(
     const std::string &, const std::string &, const std::string &);
 static ModuleCheckSumType ComputeCheckSum(const std::string_view &);
 static std::string CheckSumString(ModuleCheckSumType);
+static bool ProgramHasCUDAAttrs(const parser::Program &);
 
 // Collect symbols needed for a subprogram interface
 class SubprogramSymbolCollector {
@@ -1703,6 +1705,13 @@ Scope *ModFileReader::Read(SourceName name, std::optional<bool> isIntrinsic,
     return nullptr;
   }
   parser::Program &parseTree{context_.SaveParseTree(std::move(*parsedProgram))};
+  if (context_.languageFeatures().IsEnabled(common::LanguageFeature::OpenACC) &&
+      !context_.languageFeatures().IsEnabled(common::LanguageFeature::CUDA) &&
+      ProgramHasCUDAAttrs(parseTree)) {
+    Say("use", name, ancestorName,
+        "CUDA is not enabled, but '%s' defines CUDA symbols"_err_en_US,
+        sourceFile->path());
+  }
   Scope *parentScope; // the scope this module/submodule goes into
   if (!isIntrinsic.has_value()) {
     for (const auto &dir : context_.intrinsicModuleDirectories()) {
@@ -1823,6 +1832,26 @@ static std::optional<SourceName> GetSubmoduleParent(
   }
 }
 
+struct CUDAAttrProgramVisitor {
+  template <typename A> bool Pre(const A &) { return true; }
+  template <typename A> void Post(const A &) {}
+  bool Pre(const common::CUDADataAttr &) {
+    foundCUDAAttrs = true;
+    return false;
+  }
+  bool Pre(const common::CUDASubprogramAttrs &) {
+    foundCUDAAttrs = true;
+    return false;
+  }
+  bool foundCUDAAttrs{false};
+};
+
+static bool ProgramHasCUDAAttrs(const parser::Program &program) {
+  CUDAAttrProgramVisitor visitor;
+  parser::Walk(program, visitor);
+  return visitor.foundCUDAAttrs;
+}
+
 void SubprogramSymbolCollector::Collect() {
   const auto &details{symbol_.get<SubprogramDetails>()};
   isInterface_ = details.isInterface();

diff  --git a/flang/test/Semantics/modfile84.f90 b/flang/test/Semantics/modfile84.f90
new file mode 100644
index 0000000000000..2abcd8083eea6
--- /dev/null
+++ b/flang/test/Semantics/modfile84.f90
@@ -0,0 +1,17 @@
+! RUN: split-file %s %t
+! RUN: %flang_fc1 -fsyntax-only -x cuda -module-dir %t %t/m.cuf
+! RUN: not %flang_fc1 -fsyntax-only -fopenacc -module-dir %t %t/use.f90 2>&1 | FileCheck %s
+
+!--- m.cuf
+module modfile84m
+  real, device :: d
+contains
+  attributes(device) subroutine s()
+  end subroutine
+end module
+
+!--- use.f90
+use modfile84m
+end
+
+! CHECK: error: Cannot use module file for module 'modfile84m': CUDA is not enabled, but '{{.*modfile84m.mod}}' defines CUDA symbols