Update the Pass→std::move() tool to handle nested calls to Pass().

tools/clang/pass_to_move/PassToMove.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Clang tool to change calls to scoper::Pass() to just use std::move().
 
 #include <memory>
 #include <string>
 
 #include "clang/AST/ASTContext.h"
@@ skipping 23 matching lines @@
       : replacements_(replacements) {}
   virtual void run(const MatchFinder::MatchResult& result) override;
 
  private:
   Replacements* const replacements_;
 };
 
 void RewriterCallback::run(const MatchFinder::MatchResult& result) {
   const clang::CXXMemberCallExpr* call_expr =
       result.Nodes.getNodeAs<clang::CXXMemberCallExpr>("expr");
-  const bool is_arrow =
-      clang::dyn_cast<clang::MemberExpr>(call_expr->getCallee())->isArrow();
+  const clang::MemberExpr* callee =
+      clang::dyn_cast<clang::MemberExpr>(call_expr->getCallee());
+  const bool is_arrow = callee->isArrow();
   const clang::Expr* arg = result.Nodes.getNodeAs<clang::Expr>("arg");
 
-  clang::CharSourceRange arg_range = clang::CharSourceRange::getTokenRange(
-      result.SourceManager->getSpellingLoc(arg->getLocStart()),
-      result.SourceManager->getSpellingLoc(arg->getLocEnd()));
-  std::string new_source_text = "std::move(";
-  if (is_arrow)
-    new_source_text += "*";
-  llvm::StringRef arg_text = clang::Lexer::getSourceText(
-      arg_range, *result.SourceManager, result.Context->getLangOpts());
-  new_source_text.append(arg_text.data(), arg_text.size());
-  new_source_text += ")";
+  const char kMoveRefText[] = "std::move(";
+  const char kMovePtrText[] = "std::move(*";
 
-  // Replace the entire original expression with std::move(arg).
-  clang::CharSourceRange expr_range = clang::CharSourceRange::getTokenRange(
-      result.SourceManager->getSpellingLoc(call_expr->getLocStart()),
-      result.SourceManager->getSpellingLoc(call_expr->getLocEnd()));
-  replacements_->emplace(*result.SourceManager, expr_range, new_source_text);
+  replacements_->emplace(*result.SourceManager,
+                         result.SourceManager->getSpellingLoc(
+                             arg->getLocStart()),
+                         0,
+                         is_arrow ? kMovePtrText : kMoveRefText);
+
+  // Delete everything but the closing parentheses from the original call to
+  // Pass(): the closing parantheses is left to match up with the parantheses
+  // just inserted with std::move.
+  replacements_->emplace(*result.SourceManager,
+                         clang::CharSourceRange::getCharRange(
+                             result.SourceManager->getSpellingLoc(
+                                 callee->getOperatorLoc()),
+                             result.SourceManager->getSpellingLoc(
+                                 call_expr->getRParenLoc())),
+                         "");
 }
 
 }  // namespace
 
 static llvm::cl::extrahelp common_help(CommonOptionsParser::HelpMessage);
 
 int main(int argc, const char* argv[]) {
   // TODO(dcheng): Clang tooling should do this itself.
   // http://llvm.org/bugs/show_bug.cgi?id=21627
   llvm::InitializeNativeTarget();
@@ skipping 27 matching lines @@
   for (const auto& r : replacements) {
     std::string replacement_text = r.getReplacementText().str();
     std::replace(replacement_text.begin(), replacement_text.end(), '\n', '\0');
     llvm::outs() << "r:::" << r.getFilePath() << ":::" << r.getOffset()
                  << ":::" << r.getLength() << ":::" << replacement_text << "\n";
   }
   llvm::outs() << "==== END EDITS ====\n";
 
   return 0;
 }