clang/lib/DependencyScanning/DependencyScanningWorker.cpp

//===- DependencyScanningWorker.cpp - Thread-Safe Scanning Worker ---------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "clang/DependencyScanning/DependencyScanningWorker.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/DiagnosticFrontend.h"
#include "clang/DependencyScanning/DependencyScannerImpl.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/Tool.h"
#include "clang/Serialization/ObjectFilePCHContainerReader.h"
#include "llvm/Support/VirtualFileSystem.h"

using namespace clang;
using namespace dependencies;

DependencyScanningWorker::DependencyScanningWorker(
    DependencyScanningService &Service,
    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS)
    : Service(Service) {
  PCHContainerOps = std::make_shared<PCHContainerOperations>();
  // We need to read object files from PCH built outside the scanner.
  PCHContainerOps->registerReader(
      std::make_unique<ObjectFilePCHContainerReader>());
  // The scanner itself writes only raw ast files.
  PCHContainerOps->registerWriter(std::make_unique<RawPCHContainerWriter>());

  if (Service.shouldTraceVFS())
    BaseFS = llvm::makeIntrusiveRefCnt<llvm::vfs::TracingFileSystem>(
        std::move(BaseFS));

  DepFS = llvm::makeIntrusiveRefCnt<DependencyScanningWorkerFilesystem>(
      Service.getSharedCache(), std::move(BaseFS));
}

DependencyScanningWorker::~DependencyScanningWorker() = default;
DependencyActionController::~DependencyActionController() = default;

static bool forEachDriverJob(
    ArrayRef<std::string> ArgStrs, DiagnosticsEngine &Diags,
    IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
    llvm::function_ref<bool(const driver::Command &Cmd)> Callback) {
  // Compilation holds a non-owning a reference to the Driver, hence we need to
  // keep the Driver alive when we use Compilation. Arguments to commands may be
  // owned by Alloc when expanded from response files.
  llvm::BumpPtrAllocator Alloc;
  auto [Driver, Compilation] = buildCompilation(ArgStrs, Diags, FS, Alloc);
  if (!Compilation)
    return false;
  for (const driver::Command &Job : Compilation->getJobs()) {
    if (!Callback(Job))
      return false;
  }
  return true;
}

static bool createAndRunToolInvocation(
    ArrayRef<std::string> CommandLine, DependencyScanningAction &Action,
    IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
    std::shared_ptr<clang::PCHContainerOperations> &PCHContainerOps,
    DiagnosticsEngine &Diags) {
  auto Invocation = createCompilerInvocation(CommandLine, Diags);
  if (!Invocation)
    return false;

  return Action.runInvocation(CommandLine[0], std::move(Invocation),
                              std::move(FS), PCHContainerOps,
                              Diags.getClient());
}

bool DependencyScanningWorker::scanDependencies(
    StringRef WorkingDirectory, ArrayRef<std::string> CommandLine,
    DependencyConsumer &Consumer, DependencyActionController &Controller,
    DiagnosticConsumer &DC,
    IntrusiveRefCntPtr<llvm::vfs::FileSystem> OverlayFS) {
  IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = DepFS;
  if (OverlayFS) {
#ifndef NDEBUG
    bool SawDepFS = false;
    OverlayFS->visit(
        [&](llvm::vfs::FileSystem &VFS) { SawDepFS |= &VFS == DepFS.get(); });
    assert(SawDepFS && "OverlayFS not based on DepFS");
#endif
    FS = std::move(OverlayFS);
  }

  DiagnosticsEngineWithDiagOpts DiagEngineWithCmdAndOpts(CommandLine, FS, DC);
  DependencyScanningAction Action(Service, WorkingDirectory, Consumer,
                                  Controller, DepFS);

  bool Success = false;
  if (CommandLine[1] == "-cc1") {
    Success =
        createAndRunToolInvocation(CommandLine, Action, FS, PCHContainerOps,
                                   *DiagEngineWithCmdAndOpts.DiagEngine);
  } else {
    Success = forEachDriverJob(
        CommandLine, *DiagEngineWithCmdAndOpts.DiagEngine, FS,
        [&](const driver::Command &Cmd) {
          if (StringRef(Cmd.getCreator().getName()) != "clang") {
            // Non-clang command. Just pass through to the dependency
            // consumer.
            Consumer.handleBuildCommand(
                {Cmd.getExecutable(),
                 {Cmd.getArguments().begin(), Cmd.getArguments().end()}});
            return true;
          }

          // Insert -cc1 command line options into Argv
          std::vector<std::string> Argv;
          Argv.push_back(Cmd.getExecutable());
          llvm::append_range(Argv, Cmd.getArguments());

          // Create an invocation that uses the underlying file
          // system to ensure that any file system requests that
          // are made by the driver do not go through the
          // dependency scanning filesystem.
          return createAndRunToolInvocation(
              std::move(Argv), Action, FS, PCHContainerOps,
              *DiagEngineWithCmdAndOpts.DiagEngine);
        });
  }

  if (Success && !Action.hasScanned())
    DiagEngineWithCmdAndOpts.DiagEngine->Report(
        diag::err_fe_expected_compiler_job)
        << llvm::join(CommandLine, " ");

  // Ensure finish() is called even if we never reached ExecuteAction().
  if (!Action.hasDiagConsumerFinished())
    DC.finish();

  return Success && Action.hasScanned();
}

bool DependencyScanningWorker::computeDependencies(
    StringRef WorkingDirectory, ArrayRef<std::string> CommandLine,
    DependencyConsumer &Consumer, DependencyActionController &Controller,
    DiagnosticConsumer &DC, std::optional<llvm::MemoryBufferRef> TUBuffer) {
  if (TUBuffer) {
    auto [FinalFS, FinalCommandLine] = initVFSForTUBufferScanning(
        DepFS, CommandLine, WorkingDirectory, *TUBuffer);
    return scanDependencies(WorkingDirectory, FinalCommandLine, Consumer,
                            Controller, DC, FinalFS);
  }

  DepFS->setCurrentWorkingDirectory(WorkingDirectory);
  return scanDependencies(WorkingDirectory, CommandLine, Consumer, Controller,
                          DC);
}

bool DependencyScanningWorker::initializeCompilerInstanceWithContext(
    StringRef CWD, ArrayRef<std::string> CommandLine, DiagnosticConsumer &DC) {
  auto [OverlayFS, ModifiedCommandLine] =
      initVFSForByNameScanning(DepFS, CommandLine, CWD, "ScanningByName");
  auto DiagEngineWithCmdAndOpts =
      std::make_unique<DiagnosticsEngineWithDiagOpts>(ModifiedCommandLine,
                                                      OverlayFS, DC);
  return initializeCompilerInstanceWithContext(
      CWD, ModifiedCommandLine, std::move(DiagEngineWithCmdAndOpts), OverlayFS);
}

bool DependencyScanningWorker::initializeCompilerInstanceWithContext(
    StringRef CWD, ArrayRef<std::string> CommandLine,
    std::unique_ptr<DiagnosticsEngineWithDiagOpts> DiagEngineWithDiagOpts,
    IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFS) {
  CIWithContext =
      std::make_unique<CompilerInstanceWithContext>(*this, CWD, CommandLine);
  return CIWithContext->initialize(std::move(DiagEngineWithDiagOpts),
                                   OverlayFS);
}

bool DependencyScanningWorker::computeDependenciesByNameWithContext(
    StringRef ModuleName, DependencyConsumer &Consumer,
    DependencyActionController &Controller) {
  assert(CIWithContext && "CompilerInstance with context required!");
  return CIWithContext->computeDependencies(ModuleName, Consumer, Controller);
}

bool DependencyScanningWorker::finalizeCompilerInstanceWithContext() {
  return CIWithContext->finalize();
}