Implement -Wpass-global-variable flag for flang

Author: foxtran

flang/include/flang/Support/Fortran-features.h

@@ -79,7 +79,7 @@ ENUM_CLASS(UsageWarning, Portability, PointerToUndefinable,
     CompatibleDeclarationsFromDistinctModules,
     NullActualForDefaultIntentAllocatable, UseAssociationIntoSameNameSubprogram,
     HostAssociatedIntentOutInSpecExpr, NonVolatilePointerToVolatile,
-    RealConstantWidening, VolatileOrAsynchronousTemporary)
+    RealConstantWidening, VolatileOrAsynchronousTemporary, PassGlobalVariable)
 
 using LanguageFeatures = EnumSet<LanguageFeature, LanguageFeature_enumSize>;
 using UsageWarnings = EnumSet<UsageWarning, UsageWarning_enumSize>;

flang/lib/Support/Fortran-features.cpp

@@ -149,6 +149,7 @@ LanguageFeatureControl::LanguageFeatureControl() {
   warnUsage_.set(UsageWarning::HostAssociatedIntentOutInSpecExpr);
   warnUsage_.set(UsageWarning::NonVolatilePointerToVolatile);
   warnUsage_.set(UsageWarning::RealConstantWidening);
+  warnUsage_.set(UsageWarning::PassGlobalVariable);
   // New warnings, on by default
   warnLanguage_.set(LanguageFeature::SavedLocalInSpecExpr);
   warnLanguage_.set(LanguageFeature::NullActualForAllocatable);

flang/unittests/Common/FortranFeaturesTest.cpp

@@ -556,6 +556,9 @@ TEST(FortranFeaturesTest, CamelCaseToLowerCaseHyphenated) {
   EXPECT_EQ(CamelCaseToLowerCaseHyphenated(
                 EnumToString(UsageWarning::NonVolatilePointerToVolatile)),
       "non-volatile-pointer-to-volatile");
+  EXPECT_EQ(
+      CamelCaseToLowerCaseHyphenated(EnumToString(UsageWarning::PassGlobalVariable)),
+      "pass-global-variable");
 }
 
 TEST(FortranFeaturesTest, HintLanguageControlFlag) {