ARCMigrate: Stop abusing PreprocessorOptions for passing back file remappings, NFC

[dexonsmith]

Summary

As part of reducing use of PreprocessorOptions::RemappedFileBuffers, stop abusing it to pass information around remapped files in ARCMigrate. This simplifies an eventual follow-up to switch to using an InMemoryFileSystem for this.

[dexonsmith]

ping

[dexonsmith]

ping

[jansvoboda11]

LGTM.

clang/include/clang/ARCMigrate/FileRemapper.h

 //===-- FileRemapper.h - File Remapping Helper ------------------*- 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
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_ARCMIGRATE_FILEREMAPPER_H
 #define LLVM_CLANG_ARCMIGRATE_FILEREMAPPER_H
 
 #include "clang/Basic/LLVM.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/PointerUnion.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include <memory>
 
 namespace llvm {
   class MemoryBuffer;
+  class MemoryBufferRef;
 }
 
 namespace clang {
   class FileManager;
   class FileEntry;
   class DiagnosticsEngine;
   class PreprocessorOptions;
 
public:
 
   bool overwriteOriginal(DiagnosticsEngine &Diag,
                          StringRef outputDir = StringRef());
 
   void remap(StringRef filePath, std::unique_ptr<llvm::MemoryBuffer> memBuf);
 
   void applyMappings(PreprocessorOptions &PPOpts) const;
 
+  /// Iterate through all the mappings.
+  void forEachMapping(
+      llvm::function_ref<void(StringRef, StringRef)> CaptureFile,
+      llvm::function_ref<void(StringRef, const llvm::MemoryBufferRef &)>
+          CaptureBuffer) const;
+
   void clear(StringRef outputDir = StringRef());
 
 private:
   void remap(const FileEntry *file, std::unique_ptr<llvm::MemoryBuffer> memBuf);
   void remap(const FileEntry *file, const FileEntry *newfile);
 
   const FileEntry *getOriginalFile(StringRef filePath);
   void resetTarget(Target &targ);

clang/lib/ARCMigrate/ARCMT.cpp

IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
                             DiagClient, /*ShouldOwnClient=*/false));
 
   FileRemapper remapper;
   bool err = remapper.initFromDisk(outputDir, *Diags,
                                    /*ignoreIfFilesChanged=*/true);
   if (err)
     return true;
 
-  PreprocessorOptions PPOpts;
-  remapper.applyMappings(PPOpts);
-  remap = PPOpts.RemappedFiles;
+  remapper.forEachMapping(
+      [&](StringRef From, StringRef To) {
+        remap.push_back(std::make_pair(From.str(), To.str()));
+      },
+      [](StringRef, const llvm::MemoryBufferRef &) {});
 
   return false;
 }
 
 
 //===----------------------------------------------------------------------===//
 // CollectTransformActions.
 //===----------------------------------------------------------------------===//

clang/lib/ARCMigrate/FileRemapper.cpp

for (MappingsTy::iterator
     Out.write(mem->getBufferStart(), mem->getBufferSize());
     Out.close();
   }
 
   clear(outputDir);
   return false;
 }
 
+void FileRemapper::forEachMapping(
+    llvm::function_ref<void(StringRef, StringRef)> CaptureFile,
+    llvm::function_ref<void(StringRef, const llvm::MemoryBufferRef &)>
+        CaptureBuffer) const {
+  for (auto &Mapping : FromToMappings) {
+    if (const FileEntry *FE = Mapping.second.dyn_cast<const FileEntry *>()) {
+      CaptureFile(Mapping.first->getName(), FE->getName());
+      continue;
+    }
+    CaptureBuffer(
+        Mapping.first->getName(),
+        Mapping.second.get<llvm::MemoryBuffer *>()->getMemBufferRef());
+  }
+}
+
 void FileRemapper::applyMappings(PreprocessorOptions &PPOpts) const {
   for (MappingsTy::const_iterator
          I = FromToMappings.begin(), E = FromToMappings.end(); I != E; ++I) {
     if (const FileEntry *FE = I->second.dyn_cast<const FileEntry *>()) {
       PPOpts.addRemappedFile(I->first->getName(), FE->getName());
     } else {
       llvm::MemoryBuffer *mem = I->second.get<llvm::MemoryBuffer *>();
       PPOpts.addRemappedFile(I->first->getName(), mem);

clang/tools/arcmt-test/arcmt-test.cpp

static bool checkForMigration(StringRef resourcesPath,
 
   arcmt::checkForManualIssues(CI, CI.getFrontendOpts().Inputs[0],
                               std::make_shared<PCHContainerOperations>(),
                               Diags->getClient());
   return Diags->getClient()->getNumErrors() > 0;
 }
 
 static void printResult(FileRemapper &remapper, raw_ostream &OS) {
-  PreprocessorOptions PPOpts;
-  remapper.applyMappings(PPOpts);
-  // The changed files will be in memory buffers, print them.
-  for (const auto &RB : PPOpts.RemappedFileBuffers)
-    OS << RB.second->getBuffer();
+  remapper.forEachMapping([](StringRef, StringRef) {},
+                          [&](StringRef, const llvm::MemoryBufferRef &Buffer) {
+                            OS << Buffer.getBuffer();
+                          });
 }
 
 static bool performTransformations(StringRef resourcesPath,
                                    ArrayRef<const char *> Args) {
   // Check first.
   if (checkForMigration(resourcesPath, Args))
     return true;