//===--- tools/clang-check/ClangCheck.cpp - Clang check tool --------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
//  This file implements a clang-check tool that runs clang based on the info
//  stored in a compilation database.
//
//  This tool uses the Clang Tooling infrastructure, see
//    http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
//  for details on setting it up with LLVM source tree.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/ASTConsumer.h"
#include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
#include "clang/Driver/Options.h"
#include "clang/Frontend/ASTConsumers.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Rewrite/Frontend/FixItRewriter.h"
#include "clang/Rewrite/Frontend/FrontendActions.h"
#include "clang/StaticAnalyzer/Frontend/FrontendActions.h"
#include "clang/Tooling/CommonOptionsParser.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Option/OptTable.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/TargetSelect.h"

using namespace clang::driver;
using namespace clang::tooling;
using namespace llvm;

static cl::extrahelp CommonHelp(CommonOptionsParser::HelpMessage);
static cl::extrahelp MoreHelp(
    "\tFor example, to run clang-check on all files in a subtree of the\n"
    "\tsource tree, use:\n"
    "\n"
    "\t  find path/in/subtree -name '*.cpp'|xargs clang-check\n"
    "\n"
    "\tor using a specific build path:\n"
    "\n"
    "\t  find path/in/subtree -name '*.cpp'|xargs clang-check -p build/path\n"
    "\n"
    "\tNote, that path/in/subtree and current directory should follow the\n"
    "\trules described above.\n"
    "\n"
);

static cl::OptionCategory ClangCheckCategory("clang-check options");
static const opt::OptTable &Options = getDriverOptTable();
static cl::opt<bool>
    ASTDump("ast-dump",
            cl::desc(Options.getOptionHelpText(options::OPT_ast_dump)),
            cl::cat(ClangCheckCategory));
static cl::opt<bool>
    ASTList("ast-list",
            cl::desc(Options.getOptionHelpText(options::OPT_ast_list)),
            cl::cat(ClangCheckCategory));
static cl::opt<bool>
    ASTPrint("ast-print",
             cl::desc(Options.getOptionHelpText(options::OPT_ast_print)),
             cl::cat(ClangCheckCategory));
static cl::opt<std::string> ASTDumpFilter(
    "ast-dump-filter",
    cl::desc(Options.getOptionHelpText(options::OPT_ast_dump_filter)),
    cl::cat(ClangCheckCategory));
static cl::opt<bool>
    Analyze("analyze",
            cl::desc(Options.getOptionHelpText(options::OPT_analyze)),
            cl::cat(ClangCheckCategory));

static cl::opt<bool>
    Fixit("fixit", cl::desc(Options.getOptionHelpText(options::OPT_fixit)),
          cl::cat(ClangCheckCategory));
static cl::opt<bool> FixWhatYouCan(
    "fix-what-you-can",
    cl::desc(Options.getOptionHelpText(options::OPT_fix_what_you_can)),
    cl::cat(ClangCheckCategory));

namespace {

// FIXME: Move FixItRewriteInPlace from lib/Rewrite/Frontend/FrontendActions.cpp
// into a header file and reuse that.
class FixItOptions : public clang::FixItOptions {
public:
  FixItOptions() {
    FixWhatYouCan = ::FixWhatYouCan;
  }

  std::string RewriteFilename(const std::string& filename, int &fd) override {
    // We don't need to do permission checking here since clang will diagnose
    // any I/O errors itself.

    fd = -1;  // No file descriptor for file.

    return filename;
  }
};

/// Subclasses \c clang::FixItRewriter to not count fixed errors/warnings
/// in the final error counts.
///
/// This has the side-effect that clang-check -fixit exits with code 0 on
/// successfully fixing all errors.
class FixItRewriter : public clang::FixItRewriter {
public:
  FixItRewriter(clang::DiagnosticsEngine& Diags,
                clang::SourceManager& SourceMgr,
                const clang::LangOptions& LangOpts,
                clang::FixItOptions* FixItOpts)
      : clang::FixItRewriter(Diags, SourceMgr, LangOpts, FixItOpts) {
  }

  bool IncludeInDiagnosticCounts() const override { return false; }
};

/// Subclasses \c clang::FixItAction so that we can install the custom
/// \c FixItRewriter.
class ClangCheckFixItAction : public clang::FixItAction {
public:
  bool BeginSourceFileAction(clang::CompilerInstance& CI) override {
    FixItOpts.reset(new FixItOptions);
    Rewriter.reset(new FixItRewriter(CI.getDiagnostics(), CI.getSourceManager(),
                                     CI.getLangOpts(), FixItOpts.get()));
    return true;
  }
};

class ClangCheckActionFactory {
public:
  std::unique_ptr<clang::ASTConsumer> newASTConsumer() {
    if (ASTList)
      return clang::CreateASTDeclNodeLister();
    if (ASTDump)
      return clang::CreateASTDumper(nullptr /*Dump to stdout.*/, ASTDumpFilter,
                                    /*DumpDecls=*/true,
                                    /*Deserialize=*/false,
                                    /*DumpLookups=*/false,
                                    clang::ADOF_Default);
    if (ASTPrint)
      return clang::CreateASTPrinter(nullptr, ASTDumpFilter);
    return std::make_unique<clang::ASTConsumer>();
  }
};

} // namespace

int main(int argc, const char **argv) {
  llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);

  // Initialize targets for clang module support.
  llvm::InitializeAllTargets();
  llvm::InitializeAllTargetMCs();
  llvm::InitializeAllAsmPrinters();
  llvm::InitializeAllAsmParsers();

  CommonOptionsParser OptionsParser(argc, argv, ClangCheckCategory);
  ClangTool Tool(OptionsParser.getCompilations(),
                 OptionsParser.getSourcePathList());

  // Clear adjusters because -fsyntax-only is inserted by the default chain.
  Tool.clearArgumentsAdjusters();
  Tool.appendArgumentsAdjuster(getClangStripOutputAdjuster());
  Tool.appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());

  // Running the analyzer requires --analyze. Other modes can work with the
  // -fsyntax-only option.
  Tool.appendArgumentsAdjuster(getInsertArgumentAdjuster(
      Analyze ? "--analyze" : "-fsyntax-only", ArgumentInsertPosition::BEGIN));

  ClangCheckActionFactory CheckFactory;
  std::unique_ptr<FrontendActionFactory> FrontendFactory;

  // Choose the correct factory based on the selected mode.
  if (Analyze)
    FrontendFactory = newFrontendActionFactory<clang::ento::AnalysisAction>();
  else if (Fixit)
    FrontendFactory = newFrontendActionFactory<ClangCheckFixItAction>();
  else
    FrontendFactory = newFrontendActionFactory(&CheckFactory);

  return Tool.run(FrontendFactory.get());
}