Updated Scope::FindCommonBlock() to be similar to Scope::FindSymbol(). (Currently the code doesn't fix ACC COMMON problem.)

Author: eugeneepshteyn

flang/lib/Semantics/resolve-directives.cpp

@@ -1698,21 +1698,10 @@ Symbol *AccAttributeVisitor::ResolveAccCommonBlockName(
   if (!name) {
     return nullptr;
   }
-  // Check the local and surrounding scopes first
-  if (auto *cb{GetProgramUnitOrBlockConstructContaining(GetContext().scope)
-              .FindCommonBlock(name->source)}) {
+  if (auto *cb{GetContext().scope.FindCommonBlock(name->source)}) {
     name->symbol = cb;
     return cb;
   }
-  // Look for COMMON block in the modules
-  for (const Scope &childScope : context_.globalScope().children()) {
-    if (childScope.kind() == Scope::Kind::Module) {
-      if (auto *cb{childScope.FindCommonBlock(name->source)}) {
-        name->symbol = cb;
-        return cb;
-      }
-    }
-  }
   return nullptr;
 }
 

flang/lib/Semantics/scope.cpp

@@ -155,8 +155,16 @@ Symbol &Scope::MakeCommonBlock(SourceName name, SourceName location) {
   }
 }
 Symbol *Scope::FindCommonBlock(const SourceName &name) const {
-  const auto it{commonBlocks_.find(name)};
-  return it != commonBlocks_.end() ? &*it->second : nullptr;
+  if (const auto it{commonBlocks_.find(name)}; it != commonBlocks_.end()) {
+    return &*it->second;
+  } else if (IsSubmodule()) {
+    const Scope *parent{symbol_ ? symbol_->get<ModuleDetails>().parent() : nullptr};
+    return parent ? parent->FindCommonBlock(name) : nullptr;
+  } else if (!IsTopLevel()) {
+    return parent_ ? parent_->FindCommonBlock(name) : nullptr;
+  } else {
+    return nullptr;
+  }
 }
 
 Scope *Scope::FindSubmodule(const SourceName &name) const {