//===--- Tooling.cpp - Running clang standalone tools ---------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements functions to run clang tools standalone instead
//  of running them as a plugin.
//
//===----------------------------------------------------------------------===//

#include "clang/Tooling/Tooling.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/Driver/Compilation.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/Tool.h"
#include "clang/Frontend/ASTUnit.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Tooling/ArgumentsAdjusters.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/raw_ostream.h"

// For chdir, see the comment in ClangTool::run for more information.
#ifdef LLVM_ON_WIN32
#  include <direct.h>
#else
#  include <unistd.h>
#endif

#define DEBUG_TYPE "clang-tooling"

namespace clang {
namespace tooling {

ToolAction::~ToolAction() {}

FrontendActionFactory::~FrontendActionFactory() {}

// FIXME: This file contains structural duplication with other parts of the
// code that sets up a compiler to run tools on it, and we should refactor
// it to be based on the same framework.

/// \brief Builds a clang driver initialized for running clang tools.
static clang::driver::Driver *newDriver(clang::DiagnosticsEngine *Diagnostics,
                                        const char *BinaryName) {
  clang::driver::Driver *CompilerDriver = new clang::driver::Driver(
      BinaryName, llvm::sys::getDefaultTargetTriple(), *Diagnostics);
  CompilerDriver->setTitle("clang_based_tool");
  return CompilerDriver;
}

/// \brief Retrieves the clang CC1 specific flags out of the compilation's jobs.
///
/// Returns NULL on error.
static const llvm::opt::ArgStringList *getCC1Arguments(
    clang::DiagnosticsEngine *Diagnostics,
    clang::driver::Compilation *Compilation) {
  // We expect to get back exactly one Command job, if we didn't something
  // failed. Extract that job from the Compilation.
  const clang::driver::JobList &Jobs = Compilation->getJobs();
  if (Jobs.size() != 1 || !isa<clang::driver::Command>(*Jobs.begin())) {
    SmallString<256> error_msg;
    llvm::raw_svector_ostream error_stream(error_msg);
    Jobs.Print(error_stream, "; ", true);
    Diagnostics->Report(clang::diag::err_fe_expected_compiler_job)
        << error_stream.str();
    return nullptr;
  }

  // The one job we find should be to invoke clang again.
  const clang::driver::Command &Cmd =
      cast<clang::driver::Command>(*Jobs.begin());
  if (StringRef(Cmd.getCreator().getName()) != "clang") {
    Diagnostics->Report(clang::diag::err_fe_expected_clang_command);
    return nullptr;
  }

  return &Cmd.getArguments();
}

/// \brief Returns a clang build invocation initialized from the CC1 flags.
clang::CompilerInvocation *newInvocation(
    clang::DiagnosticsEngine *Diagnostics,
    const llvm::opt::ArgStringList &CC1Args) {
  assert(!CC1Args.empty() && "Must at least contain the program name!");
  clang::CompilerInvocation *Invocation = new clang::CompilerInvocation;
  clang::CompilerInvocation::CreateFromArgs(
      *Invocation, CC1Args.data() + 1, CC1Args.data() + CC1Args.size(),
      *Diagnostics);
  Invocation->getFrontendOpts().DisableFree = false;
  Invocation->getCodeGenOpts().DisableFree = false;
  Invocation->getDependencyOutputOpts() = DependencyOutputOptions();
  return Invocation;
}

bool runToolOnCode(clang::FrontendAction *ToolAction, const Twine &Code,
                   const Twine &FileName) {
  return runToolOnCodeWithArgs(
      ToolAction, Code, std::vector<std::string>(), FileName);
}

static std::vector<std::string>
getSyntaxOnlyToolArgs(const std::vector<std::string> &ExtraArgs,
                      StringRef FileName) {
  std::vector<std::string> Args;
  Args.push_back("clang-tool");
  Args.push_back("-fsyntax-only");
  Args.insert(Args.end(), ExtraArgs.begin(), ExtraArgs.end());
  Args.push_back(FileName.str());
  return Args;
}

bool runToolOnCodeWithArgs(clang::FrontendAction *ToolAction, const Twine &Code,
                           const std::vector<std::string> &Args,
                           const Twine &FileName,
                           const FileContentMappings &VirtualMappedFiles) {

  SmallString<16> FileNameStorage;
  StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
  llvm::IntrusiveRefCntPtr<FileManager> Files(
      new FileManager(FileSystemOptions()));
  ToolInvocation Invocation(getSyntaxOnlyToolArgs(Args, FileNameRef),
                            ToolAction, Files.get());

  SmallString<1024> CodeStorage;
  Invocation.mapVirtualFile(FileNameRef,
                            Code.toNullTerminatedStringRef(CodeStorage));

  for (auto &FilenameWithContent : VirtualMappedFiles) {
    Invocation.mapVirtualFile(FilenameWithContent.first,
                              FilenameWithContent.second);
  }

  return Invocation.run();
}

std::string getAbsolutePath(StringRef File) {
  StringRef RelativePath(File);
  // FIXME: Should '.\\' be accepted on Win32?
  if (RelativePath.startswith("./")) {
    RelativePath = RelativePath.substr(strlen("./"));
  }

  SmallString<1024> AbsolutePath = RelativePath;
  std::error_code EC = llvm::sys::fs::make_absolute(AbsolutePath);
  assert(!EC);
  (void)EC;
  llvm::sys::path::native(AbsolutePath);
  return AbsolutePath.str();
}

namespace {

class SingleFrontendActionFactory : public FrontendActionFactory {
  FrontendAction *Action;

public:
  SingleFrontendActionFactory(FrontendAction *Action) : Action(Action) {}

  FrontendAction *create() override { return Action; }
};

}

ToolInvocation::ToolInvocation(std::vector<std::string> CommandLine,
                               ToolAction *Action, FileManager *Files)
    : CommandLine(std::move(CommandLine)),
      Action(Action),
      OwnsAction(false),
      Files(Files),
      DiagConsumer(nullptr) {}

ToolInvocation::ToolInvocation(std::vector<std::string> CommandLine,
                               FrontendAction *FAction, FileManager *Files)
    : CommandLine(std::move(CommandLine)),
      Action(new SingleFrontendActionFactory(FAction)),
      OwnsAction(true),
      Files(Files),
      DiagConsumer(nullptr) {}

ToolInvocation::~ToolInvocation() {
  if (OwnsAction)
    delete Action;
}

void ToolInvocation::mapVirtualFile(StringRef FilePath, StringRef Content) {
  SmallString<1024> PathStorage;
  llvm::sys::path::native(FilePath, PathStorage);
  MappedFileContents[PathStorage] = Content;
}

bool ToolInvocation::run() {
  std::vector<const char*> Argv;
  for (const std::string &Str : CommandLine)
    Argv.push_back(Str.c_str());
  const char *const BinaryName = Argv[0];
  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
  TextDiagnosticPrinter DiagnosticPrinter(
      llvm::errs(), &*DiagOpts);
  DiagnosticsEngine Diagnostics(
      IntrusiveRefCntPtr<clang::DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
      DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);

  const std::unique_ptr<clang::driver::Driver> Driver(
      newDriver(&Diagnostics, BinaryName));
  // Since the input might only be virtual, don't check whether it exists.
  Driver->setCheckInputsExist(false);
  const std::unique_ptr<clang::driver::Compilation> Compilation(
      Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
  const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
      &Diagnostics, Compilation.get());
  if (!CC1Args) {
    return false;
  }
  std::unique_ptr<clang::CompilerInvocation> Invocation(
      newInvocation(&Diagnostics, *CC1Args));
  for (const auto &It : MappedFileContents) {
    // Inject the code as the given file name into the preprocessor options.
    std::unique_ptr<llvm::MemoryBuffer> Input =
        llvm::MemoryBuffer::getMemBuffer(It.getValue());
    Invocation->getPreprocessorOpts().addRemappedFile(It.getKey(),
                                                      Input.release());
  }
  return runInvocation(BinaryName, Compilation.get(), Invocation.release());
}

bool ToolInvocation::runInvocation(
    const char *BinaryName,
    clang::driver::Compilation *Compilation,
    clang::CompilerInvocation *Invocation) {
  // Show the invocation, with -v.
  if (Invocation->getHeaderSearchOpts().Verbose) {
    llvm::errs() << "clang Invocation:\n";
    Compilation->getJobs().Print(llvm::errs(), "\n", true);
    llvm::errs() << "\n";
  }

  return Action->runInvocation(Invocation, Files, DiagConsumer);
}

bool FrontendActionFactory::runInvocation(CompilerInvocation *Invocation,
                                          FileManager *Files,
                                          DiagnosticConsumer *DiagConsumer) {
  // Create a compiler instance to handle the actual work.
  clang::CompilerInstance Compiler;
  Compiler.setInvocation(Invocation);
  Compiler.setFileManager(Files);

  // The FrontendAction can have lifetime requirements for Compiler or its
  // members, and we need to ensure it's deleted earlier than Compiler. So we
  // pass it to an std::unique_ptr declared after the Compiler variable.
  std::unique_ptr<FrontendAction> ScopedToolAction(create());

  // Create the compiler's actual diagnostics engine.
  Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
  if (!Compiler.hasDiagnostics())
    return false;

  Compiler.createSourceManager(*Files);

  const bool Success = Compiler.ExecuteAction(*ScopedToolAction);

  Files->clearStatCaches();
  return Success;
}

ClangTool::ClangTool(const CompilationDatabase &Compilations,
                     ArrayRef<std::string> SourcePaths)
    : Compilations(Compilations), SourcePaths(SourcePaths),
      Files(new FileManager(FileSystemOptions())), DiagConsumer(nullptr) {
  appendArgumentsAdjuster(getClangStripOutputAdjuster());
  appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
}

ClangTool::~ClangTool() {}

void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
  MappedFileContents.push_back(std::make_pair(FilePath, Content));
}

void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
  if (ArgsAdjuster)
    ArgsAdjuster = combineAdjusters(ArgsAdjuster, Adjuster);
  else
    ArgsAdjuster = Adjuster;
}

void ClangTool::clearArgumentsAdjusters() {
  ArgsAdjuster = nullptr;
}

int ClangTool::run(ToolAction *Action) {
  // Exists solely for the purpose of lookup of the resource path.
  // This just needs to be some symbol in the binary.
  static int StaticSymbol;
  // The driver detects the builtin header path based on the path of the
  // executable.
  // FIXME: On linux, GetMainExecutable is independent of the value of the
  // first argument, thus allowing ClangTool and runToolOnCode to just
  // pass in made-up names here. Make sure this works on other platforms.
  std::string MainExecutable =
      llvm::sys::fs::getMainExecutable("clang_tool", &StaticSymbol);

  llvm::SmallString<128> InitialDirectory;
  if (std::error_code EC = llvm::sys::fs::current_path(InitialDirectory))
    llvm::report_fatal_error("Cannot detect current path: " +
                             Twine(EC.message()));
  bool ProcessingFailed = false;
  for (const auto &SourcePath : SourcePaths) {
    std::string File(getAbsolutePath(SourcePath));

    // Currently implementations of CompilationDatabase::getCompileCommands can
    // change the state of the file system (e.g.  prepare generated headers), so
    // this method needs to run right before we invoke the tool, as the next
    // file may require a different (incompatible) state of the file system.
    //
    // FIXME: Make the compilation database interface more explicit about the
    // requirements to the order of invocation of its members.
    std::vector<CompileCommand> CompileCommandsForFile =
        Compilations.getCompileCommands(File);
    if (CompileCommandsForFile.empty()) {
      // FIXME: There are two use cases here: doing a fuzzy
      // "find . -name '*.cc' |xargs tool" match, where as a user I don't care
      // about the .cc files that were not found, and the use case where I
      // specify all files I want to run over explicitly, where this should
      // be an error. We'll want to add an option for this.
      llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
      continue;
    }
    for (CompileCommand &CompileCommand : CompileCommandsForFile) {
      // FIXME: chdir is thread hostile; on the other hand, creating the same
      // behavior as chdir is complex: chdir resolves the path once, thus
      // guaranteeing that all subsequent relative path operations work
      // on the same path the original chdir resulted in. This makes a
      // difference for example on network filesystems, where symlinks might be
      // switched during runtime of the tool. Fixing this depends on having a
      // file system abstraction that allows openat() style interactions.
      if (chdir(CompileCommand.Directory.c_str()))
        llvm::report_fatal_error("Cannot chdir into \"" +
                                 Twine(CompileCommand.Directory) + "\n!");
      std::vector<std::string> CommandLine = CompileCommand.CommandLine;
      if (ArgsAdjuster)
        CommandLine = ArgsAdjuster(CommandLine);
      assert(!CommandLine.empty());
      CommandLine[0] = MainExecutable;
      // FIXME: We need a callback mechanism for the tool writer to output a
      // customized message for each file.
      DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
      ToolInvocation Invocation(std::move(CommandLine), Action, Files.get());
      Invocation.setDiagnosticConsumer(DiagConsumer);
      for (const auto &MappedFile : MappedFileContents)
        Invocation.mapVirtualFile(MappedFile.first, MappedFile.second);
      if (!Invocation.run()) {
        // FIXME: Diagnostics should be used instead.
        llvm::errs() << "Error while processing " << File << ".\n";
        ProcessingFailed = true;
      }
      // Return to the initial directory to correctly resolve next file by
      // relative path.
      if (chdir(InitialDirectory.c_str()))
        llvm::report_fatal_error("Cannot chdir into \"" +
                                 Twine(InitialDirectory) + "\n!");
    }
  }
  return ProcessingFailed ? 1 : 0;
}

namespace {

class ASTBuilderAction : public ToolAction {
  std::vector<std::unique_ptr<ASTUnit>> &ASTs;

public:
  ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}

  bool runInvocation(CompilerInvocation *Invocation, FileManager *Files,
                     DiagnosticConsumer *DiagConsumer) override {
    // FIXME: This should use the provided FileManager.
    std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
        Invocation, CompilerInstance::createDiagnostics(
                        &Invocation->getDiagnosticOpts(), DiagConsumer,
                        /*ShouldOwnClient=*/false));
    if (!AST)
      return false;

    ASTs.push_back(std::move(AST));
    return true;
  }
};

}

int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
  ASTBuilderAction Action(ASTs);
  return run(&Action);
}

std::unique_ptr<ASTUnit> buildASTFromCode(const Twine &Code,
                                          const Twine &FileName) {
  return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName);
}

std::unique_ptr<ASTUnit>
buildASTFromCodeWithArgs(const Twine &Code,
                         const std::vector<std::string> &Args,
                         const Twine &FileName) {
  SmallString<16> FileNameStorage;
  StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);

  std::vector<std::unique_ptr<ASTUnit>> ASTs;
  ASTBuilderAction Action(ASTs);
  ToolInvocation Invocation(getSyntaxOnlyToolArgs(Args, FileNameRef), &Action,
                            nullptr);

  SmallString<1024> CodeStorage;
  Invocation.mapVirtualFile(FileNameRef,
                            Code.toNullTerminatedStringRef(CodeStorage));
  if (!Invocation.run())
    return nullptr;

  assert(ASTs.size() == 1);
  return std::move(ASTs[0]);
}

} // end namespace tooling
} // end namespace clang