llvm-project/clang-tools-extra/tool-template/ToolTemplate.cpp

//===---- tools/extra/ToolTemplate.cpp - Template for refactoring tool ----===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements an empty refactoring tool using the clang tooling.
//  The goal is to lower the "barrier to entry" for writing refactoring tools.
//
//  Usage:
//  tool-template <cmake-output-dir> <file1> <file2> ...
//
//  Where <cmake-output-dir> is a CMake build directory in which a file named
//  compile_commands.json exists (enable -DCMAKE_EXPORT_COMPILE_COMMANDS in
//  CMake to get this output).
//
//  <file1> ... specify the paths of files in the CMake source tree. This path
//  is looked up in the compile command database. If the path of a file is
//  absolute, it needs to point into CMake's source tree. If the path is
//  relative, the current working directory needs to be in the CMake source
//  tree and the file must be in a subdirectory of the current working
//  directory. "./" prefixes in the relative files will be automatically
//  removed, but the rest of a relative path must be a suffix of a path in
//  the compile command line database.
//
//  For example, to use tool-template on all files in a subtree of the
//  source tree, use:
//
//    /path/in/subtree $ find . -name '*.cpp'|
//        xargs tool-template /path/to/build
//
//===----------------------------------------------------------------------===//

#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Frontend/FrontendActions.h"
#include "clang/Lex/Lexer.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "clang/Tooling/Refactoring.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/MemoryBuffer.h"

using namespace clang;
using namespace clang::ast_matchers;
using namespace clang::tooling;
using namespace llvm;

namespace {
class ToolTemplateCallback : public MatchFinder::MatchCallback {
 public:
  ToolTemplateCallback(Replacements *Replace) : Replace(Replace) {}

  virtual void run(const MatchFinder::MatchResult &Result) {
//  TODO: This routine will get called for each thing that the matchers find.
//  At this point, you can examine the match, and do whatever you want,
//  including replacing the matched text with other text
  (void) Replace; // This to prevent an "unused member variable" warning;
  }

 private:
  Replacements *Replace;
};
} // end anonymous namespace

// Set up the command line options
cl::opt<std::string> BuildPath(
  cl::Positional,
  cl::desc("<build-path>"));

cl::list<std::string> SourcePaths(
  cl::Positional,
  cl::desc("<source0> [... <sourceN>]"),
  cl::OneOrMore);

int main(int argc, const char **argv) {
  llvm::OwningPtr<CompilationDatabase> Compilations(
        FixedCompilationDatabase::loadFromCommandLine(argc, argv));
  cl::ParseCommandLineOptions(argc, argv);
  if (!Compilations) {  // Couldn't find a compilation DB from the command line
    std::string ErrorMessage;
    Compilations.reset(
      !BuildPath.empty() ?
        CompilationDatabase::autoDetectFromDirectory(BuildPath, ErrorMessage) :
        CompilationDatabase::autoDetectFromSource(SourcePaths[0], ErrorMessage)
      );

//  Still no compilation DB? - bail.
    if (!Compilations)
      llvm::report_fatal_error(ErrorMessage);
    }
  RefactoringTool Tool(*Compilations, SourcePaths);
  ast_matchers::MatchFinder Finder;
  ToolTemplateCallback Callback(&Tool.getReplacements());

// TODO: Put your matchers here.
// Use Finder.addMatcher(...) to define the patterns in the AST that you
// want to match against. You are not limited to just one matcher!

  return Tool.run(newFrontendActionFactory(&Finder));
}