[NFC] Move writeFuncOrVarName out of class CodegenNameGenerator so that it can be reused more easily.

[plotfi]

Summary

I simply want a helper function to use for printing out mangled Decl names. I think this could be a pretty simple straightforward patch to do so, in an NFC manner.

[compnerd]

Hmm, what exactly does the libclang interfaces not give you or what exactly did you intend to have this be used as. Perhaps with some more details we can find a good solution for the specific case that you have in mind.

[plotfi]

Found a better way to do what I needed without this unnecessary change.

clang/include/clang/Index/CodegenNameGenerator.h

 //===- CodegenNameGenerator.h - Codegen name generation -------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // Determines the name that the symbol will get for code generation.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_INDEX_CODEGENNAMEGENERATOR_H
 #define LLVM_CLANG_INDEX_CODEGENNAMEGENERATOR_H
 
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/Mangle.h"
 #include "clang/Basic/LLVM.h"
+#include "llvm/Support/raw_ostream.h"
 #include <memory>
 #include <string>
 #include <vector>
 
 namespace clang {
   class ASTContext;
   class Decl;
 
 namespace index {
 
+bool writeFuncOrVarName(MangleContext *MC, const NamedDecl *D, raw_ostream &OS);
+
 class CodegenNameGenerator {
 public:
   explicit CodegenNameGenerator(ASTContext &Ctx);
   ~CodegenNameGenerator();
 
   /// \returns true on failure to produce a name for the given decl, false on
   /// success.
   bool writeName(const Decl *D, raw_ostream &OS);

clang/lib/Index/CodegenNameGenerator.cpp

 #include "clang/Basic/TargetInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace clang;
 using namespace clang::index;
 
+namespace clang {
+namespace index {
+bool writeFuncOrVarName(MangleContext *MC, const NamedDecl *D,
+                        raw_ostream &OS) {
+  if (MC->shouldMangleDeclName(D)) {
+    if (const auto *CtorD = dyn_cast<CXXConstructorDecl>(D))
+      MC->mangleCXXCtor(CtorD, Ctor_Complete, OS);
+    else if (const auto *DtorD = dyn_cast<CXXDestructorDecl>(D))
+      MC->mangleCXXDtor(DtorD, Dtor_Complete, OS);
+    else
+      MC->mangleName(D, OS);
+    return false;
+  } else {
+    IdentifierInfo *II = D->getIdentifier();
+    if (!II)
+      return true;
+    OS << II->getName();
+    return false;
+  }
+}
+} // namespace index
+} // namespace clang
+
 struct CodegenNameGenerator::Implementation {
   std::unique_ptr<MangleContext> MC;
   llvm::DataLayout DL;
 
   Implementation(ASTContext &Ctx)
     : MC(Ctx.createMangleContext()),
       DL(Ctx.getTargetInfo().getDataLayout()) {}
 
if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND)) {
             Manglings.emplace_back(getMangledThunk(MD, T));
     }
 
     return Manglings;
   }
 
 private:
   bool writeFuncOrVarName(const NamedDecl *D, raw_ostream &OS) {
-    if (MC->shouldMangleDeclName(D)) {
-      if (const auto *CtorD = dyn_cast<CXXConstructorDecl>(D))
-        MC->mangleCXXCtor(CtorD, Ctor_Complete, OS);
-      else if (const auto *DtorD = dyn_cast<CXXDestructorDecl>(D))
-        MC->mangleCXXDtor(DtorD, Dtor_Complete, OS);
-      else
-        MC->mangleName(D, OS);
-      return false;
-    } else {
-      IdentifierInfo *II = D->getIdentifier();
-      if (!II)
-        return true;
-      OS << II->getName();
-      return false;
-    }
+    return clang::index::writeFuncOrVarName(MC.get(), D, OS);
   }
 
   void writeObjCClassName(const ObjCInterfaceDecl *D, raw_ostream &OS) {
     OS << getClassSymbolPrefix(ObjCClass, D->getASTContext());
     OS << D->getObjCRuntimeNameAsString();
   }
 
   static StringRef getClassSymbolPrefix(ObjCKind Kind, const ASTContext &Context) {