[clang] Extract attribute plugin instantiation to function (NFC)

[wanders]

Summary

This moves the code to instantiate the attribute plugins to the same
place where the plugin registry is defined so they live together and the
user of the plugins doesn't have the burden of instantiating the
plugins.

No functional change intended.

clang/include/clang/Basic/ParsedAttrInfo.h

 #ifndef LLVM_CLANG_BASIC_PARSEDATTRINFO_H
 #define LLVM_CLANG_BASIC_PARSEDATTRINFO_H
 
 #include "clang/Basic/AttrSubjectMatchRules.h"
 #include "clang/Basic/AttributeCommonInfo.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/Registry.h"
 #include <climits>
+#include <list>
 
 namespace clang {
 
 class Decl;
 class LangOptions;
 class ParsedAttr;
 class Sema;
 class Stmt;
public:
   }
 
   static const ParsedAttrInfo &get(const AttributeCommonInfo &A);
   static ArrayRef<const ParsedAttrInfo *> getAllBuiltin();
 };
 
 typedef llvm::Registry<ParsedAttrInfo> ParsedAttrInfoRegistry;
 
+const std::list<std::unique_ptr<ParsedAttrInfo>> &getAttributePluginInstances();
+
 } // namespace clang
 
 #endif // LLVM_CLANG_BASIC_PARSEDATTRINFO_H

clang/lib/Basic/ParsedAttrInfo.cpp

 //===- ParsedAttrInfo.cpp - Registry for attribute plugins ------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file contains the Registry of attributes added by plugins which
 // derive the ParsedAttrInfo class.
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/ParsedAttrInfo.h"
+#include "llvm/Support/ManagedStatic.h"
+#include <list>
+#include <memory>
 
 using namespace clang;
 
 LLVM_INSTANTIATE_REGISTRY(ParsedAttrInfoRegistry)
+
+const std::list<std::unique_ptr<ParsedAttrInfo>> &
+clang::getAttributePluginInstances() {
+  static llvm::ManagedStatic<std::list<std::unique_ptr<ParsedAttrInfo>>>
+      PluginAttrInstances;
+  if (PluginAttrInstances->empty())
+    for (auto It : ParsedAttrInfoRegistry::entries())
+      PluginAttrInstances->emplace_back(It.instantiate());
+
+  return *PluginAttrInstances;
+}

clang/lib/Sema/ParsedAttr.cpp

 #include "clang/AST/ASTContext.h"
 #include "clang/Basic/AttrSubjectMatchRules.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Sema/SemaInternal.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Support/ManagedStatic.h"
 #include <cassert>
 #include <cstddef>
 #include <utility>
 
 using namespace clang;
 
 IdentifierLoc *IdentifierLoc::create(ASTContext &Ctx, SourceLocation Loc,
                                      IdentifierInfo *Ident) {
if ((size_t)A.getParsedKind() < std::size(AttrInfoMap))
     return *AttrInfoMap[A.getParsedKind()];
 
   // If this is an ignored attribute then return an appropriate ParsedAttrInfo.
   static const ParsedAttrInfo IgnoredParsedAttrInfo(
       AttributeCommonInfo::IgnoredAttribute);
   if (A.getParsedKind() == AttributeCommonInfo::IgnoredAttribute)
     return IgnoredParsedAttrInfo;
 
-  // Otherwise this may be an attribute defined by a plugin. First instantiate
-  // all plugin attributes if we haven't already done so.
-  static llvm::ManagedStatic<std::list<std::unique_ptr<ParsedAttrInfo>>>
-      PluginAttrInstances;
-  if (PluginAttrInstances->empty())
-    for (auto It : ParsedAttrInfoRegistry::entries())
-      PluginAttrInstances->emplace_back(It.instantiate());
+  // Otherwise this may be an attribute defined by a plugin.
 
   // Search for a ParsedAttrInfo whose name and syntax match.
   std::string FullName = A.getNormalizedFullName();
   AttributeCommonInfo::Syntax SyntaxUsed = A.getSyntax();
   if (SyntaxUsed == AttributeCommonInfo::AS_ContextSensitiveKeyword)
     SyntaxUsed = AttributeCommonInfo::AS_Keyword;
 
-  for (auto &Ptr : *PluginAttrInstances)
+  for (auto &Ptr : getAttributePluginInstances())
     for (auto &S : Ptr->Spellings)
       if (S.Syntax == SyntaxUsed && S.NormalizedFullName == FullName)
         return *Ptr;
 
   // If we failed to find a match then return a default ParsedAttrInfo.
   static const ParsedAttrInfo DefaultParsedAttrInfo(
       AttributeCommonInfo::UnknownAttribute);
   return DefaultParsedAttrInfo;