[flang-commits] [flang] 621a7d0 - [flang] silence bogus error with BIND(C) variable in hermetic module (#143737)

[via flang-commits]

Author: jeanPerier
Date: 2025-06-11T19:02:47+02:00
New Revision: 621a7d0f66f3da27e687dd7dd832450334ee81da

URL: https://github.com/llvm/llvm-project/commit/621a7d0f66f3da27e687dd7dd832450334ee81da
DIFF: https://github.com/llvm/llvm-project/commit/621a7d0f66f3da27e687dd7dd832450334ee81da.diff

LOG: [flang] silence bogus error with BIND(C) variable in hermetic module (#143737)

The global name semantic check was firing in a bogus way when BIND(C)
variables are in hermetic module.

Do not raise the error if one of the symbol with the conflicting global
name is an "hermetic variant" of the other.

Added: 
    flang/test/Semantics/modfile76.F90

Modified: 
    flang/lib/Semantics/check-declarations.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Semantics/check-declarations.cpp b/flang/lib/Semantics/check-declarations.cpp
index 46a5b970fdf0c..f9d64485f1407 100644
--- a/flang/lib/Semantics/check-declarations.cpp
+++ b/flang/lib/Semantics/check-declarations.cpp
@@ -2958,6 +2958,14 @@ static std::optional<std::string> DefinesGlobalName(const Symbol &symbol) {
   return std::nullopt;
 }
 
+static bool IsSameSymbolFromHermeticModule(
+    const Symbol &symbol, const Symbol &other) {
+  return symbol.name() == other.name() && symbol.owner().IsModule() &&
+      other.owner().IsModule() && symbol.owner() != other.owner() &&
+      symbol.owner().GetName() &&
+      symbol.owner().GetName() == other.owner().GetName();
+}
+
 // 19.2 p2
 void CheckHelper::CheckGlobalName(const Symbol &symbol) {
   if (auto global{DefinesGlobalName(symbol)}) {
@@ -2975,6 +2983,8 @@ void CheckHelper::CheckGlobalName(const Symbol &symbol) {
           (!IsExternalProcedureDefinition(symbol) ||
               !IsExternalProcedureDefinition(other))) {
         // both are procedures/BLOCK DATA, not both definitions
+      } else if (IsSameSymbolFromHermeticModule(symbol, other)) {
+        // Both symbols are the same thing.
       } else if (symbol.has<ModuleDetails>()) {
         Warn(common::LanguageFeature::BenignNameClash, symbol.name(),
             "Module '%s' conflicts with a global name"_port_en_US,

diff  --git a/flang/test/Semantics/modfile76.F90 b/flang/test/Semantics/modfile76.F90
new file mode 100644
index 0000000000000..50ee9a088e119
--- /dev/null
+++ b/flang/test/Semantics/modfile76.F90
@@ -0,0 +1,24 @@
+!RUN: %flang_fc1 -fsyntax-only -fhermetic-module-files -DSTEP=1 %s
+!RUN: %flang_fc1 -fsyntax-only %s
+
+! Tests that a BIND(C) variable in a module A captured in a hermetic module
+! file USE'd in a module B is not creating bogus complaints about BIND(C) name
+! conflict when both module A and B are later accessed.
+
+#if STEP == 1
+module modfile75a
+  integer, bind(c) :: x
+end
+
+module modfile75b
+  use modfile75a ! capture hermetically
+end
+
+#else
+subroutine test
+  use modfile75a
+  use modfile75b
+  implicit none
+  print *, x
+end subroutine
+#endif