Add clang-reorder-fields to clang-tools-extra

This diff adds v0 of clang-reorder-fields tool to clang/tools/extra.
The main idea behind this tool is to simplify and make less error-prone refactoring of large codebases when
someone needs to change the order fields of a struct/class (for example to remove excess padding).

Differential revision: https://reviews.llvm.org/D23279

llvm-svn: 280431

1 files changed, 93 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-reorder-fields/tool/ClangReorderFields.cpp b/clang-tools-extra/clang-reorder-fields/tool/ClangReorderFields.cpp
new file mode 100644
index 00000000000..3061876c330
--- /dev/null
+++ b/clang-tools-extra/clang-reorder-fields/tool/ClangReorderFields.cpp
@@ -0,0 +1,93 @@
+//===-- tools/extra/clang-reorder-fields/tool/ClangReorderFields.cpp -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation of clang-reorder-fields tool
+///
+//===----------------------------------------------------------------------===//
+
+#include "../ReorderFieldsAction.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "clang/Tooling/CommonOptionsParser.h"
+#include "clang/Tooling/Refactoring.h"
+#include "clang/Tooling/Tooling.h"
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileSystem.h"
+#include <cstdlib>
+#include <string>
+#include <system_error>
+
+using namespace llvm;
+using namespace clang;
+
+cl::OptionCategory ClangReorderFieldsCategory("clang-reorder-fields options");
+
+static cl::opt<std::string>
+    RecordName("record-name", cl::Required,
+               cl::desc("The name of the struct/class."),
+               cl::cat(ClangReorderFieldsCategory));
+
+static cl::list<std::string> FieldsOrder("fields-order", cl::CommaSeparated,
+                                         cl::OneOrMore,
+                                         cl::desc("The desired fields order."),
+                                         cl::cat(ClangReorderFieldsCategory));
+
+static cl::opt<bool> Inplace("i", cl::desc("Overwrite edited files."),
+                             cl::cat(ClangReorderFieldsCategory));
+
+const char Usage[] = "A tool to reorder fields in C/C++ structs/classes.\n";
+
+int main(int argc, const char **argv) {
+  tooling::CommonOptionsParser OP(argc, argv, ClangReorderFieldsCategory,
+                                  Usage);
+
+  auto Files = OP.getSourcePathList();
+  tooling::RefactoringTool Tool(OP.getCompilations(), Files);
+
+  reorder_fields::ReorderFieldsAction Action(RecordName, FieldsOrder,
+                                             Tool.getReplacements());
+
+  auto Factory = tooling::newFrontendActionFactory(&Action);
+
+  if (Inplace)
+    return Tool.runAndSave(Factory.get());
+
+  int ExitCode = Tool.run(Factory.get());
+  LangOptions DefaultLangOptions;
+  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts(new DiagnosticOptions());
+  TextDiagnosticPrinter DiagnosticPrinter(errs(), &*DiagOpts);
+  DiagnosticsEngine Diagnostics(
+      IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
+      &DiagnosticPrinter, false);
+
+  auto &FileMgr = Tool.getFiles();
+  SourceManager Sources(Diagnostics, FileMgr);
+  Rewriter Rewrite(Sources, DefaultLangOptions);
+  Tool.applyAllReplacements(Rewrite);
+
+  for (const auto &File : Files) {
+    const auto *Entry = FileMgr.getFile(File);
+    const auto ID = Sources.translateFile(Entry);
+    // The method Rewriter::getRewriteBufferFor returns nullptr if
+    // the file has not been changed.
+    if (const auto *RB = Rewrite.getRewriteBufferFor(ID))
+      RB->write(outs());
+    else
+      outs() << Sources.getMemoryBufferForFile(Entry)->getBuffer();
+  }
+
+  return ExitCode;
+}