// Copyright 2014 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.rules.cpp;

import static com.google.devtools.build.lib.rules.cpp.CppRuleClasses.DYNAMIC_LINKING_MODE;
import static com.google.devtools.build.lib.rules.cpp.CppRuleClasses.STATIC_LINKING_MODE;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.Action;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.ExecutionRequirements;
import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
import com.google.devtools.build.lib.actions.ParamFileInfo;
import com.google.devtools.build.lib.actions.ParameterFile.ParameterFileType;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.MakeVariableSupplier.MapBackedMakeVariableSupplier;
import com.google.devtools.build.lib.analysis.OutputGroupInfo;
import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
import com.google.devtools.build.lib.analysis.RuleConfiguredTargetFactory;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.Runfiles;
import com.google.devtools.build.lib.analysis.RunfilesProvider;
import com.google.devtools.build.lib.analysis.RunfilesSupport;
import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
import com.google.devtools.build.lib.analysis.actions.CustomCommandLine;
import com.google.devtools.build.lib.analysis.actions.FileWriteAction;
import com.google.devtools.build.lib.analysis.actions.SpawnAction;
import com.google.devtools.build.lib.analysis.actions.SymlinkAction;
import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
import com.google.devtools.build.lib.analysis.test.ExecutionInfo;
import com.google.devtools.build.lib.analysis.test.InstrumentedFilesInfo;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.collect.nestedset.Order;
import com.google.devtools.build.lib.packages.BuiltinProvider;
import com.google.devtools.build.lib.packages.NativeInfo;
import com.google.devtools.build.lib.packages.Rule;
import com.google.devtools.build.lib.packages.TargetUtils;
import com.google.devtools.build.lib.rules.apple.ApplePlatform;
import com.google.devtools.build.lib.rules.cpp.CcCommon.CcFlagsSupplier;
import com.google.devtools.build.lib.rules.cpp.CcCompilationHelper.CompilationInfo;
import com.google.devtools.build.lib.rules.cpp.CcToolchainFeatures.FeatureConfiguration;
import com.google.devtools.build.lib.rules.cpp.CppConfiguration.DynamicMode;
import com.google.devtools.build.lib.rules.cpp.CppConfiguration.Tool;
import com.google.devtools.build.lib.rules.cpp.Link.LinkTargetType;
import com.google.devtools.build.lib.rules.cpp.Link.LinkingMode;
import com.google.devtools.build.lib.rules.cpp.LinkerInputs.LibraryToLink;
import com.google.devtools.build.lib.syntax.Type;
import com.google.devtools.build.lib.util.Pair;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * A ConfiguredTarget for <code>cc_binary</code> rules.
 */
public abstract class CcBinary implements RuleConfiguredTargetFactory {

  private final CppSemantics semantics;

  protected CcBinary(CppSemantics semantics) {
    this.semantics = semantics;
  }

  /**
   * The maximum number of inputs for any single .dwp generating action. For cases where
   * this value is exceeded, the action is split up into "batches" that fall under the limit.
   * See {@link #createDebugPackagerActions} for details.
   */
  @VisibleForTesting
  public static final int MAX_INPUTS_PER_DWP_ACTION = 100;

  /**
   * Intermediate dwps are written to this subdirectory under the main dwp's output path.
   */
  @VisibleForTesting
  public static final String INTERMEDIATE_DWP_DIR = "_dwps";

  /**
   * A string constant for the static_link_srcs feature.
   *
   * <p>Disabling this feature forces srcs of executables to be linked dynamically in
   * DYNAMIC_MODE=AUTO.
   */
  public static final String STATIC_LINK_SRCS = "static_link_srcs";

  /** Provider for native deps launchers. DO NOT USE. */
  @Deprecated
  public static class CcLauncherInfo extends NativeInfo {
    private static final String RESTRICTION_ERROR_MESSAGE =
        "This provider is restricted to native.java_binary, native.py_binary and native.java_test. "
            + "This is a ";
    public static final String PROVIDER_NAME = "CcLauncherInfo";
    public static final Provider PROVIDER = new Provider();

    private final CcCompilationOutputs ccCompilationOutputs;
    private final CcLinkParams staticModeParamsForExecutable;

    public CcLauncherInfo(
        CcLinkParams staticModeParamsForExecutable, CcCompilationOutputs ccCompilationOutputs) {
      super(PROVIDER);
      this.staticModeParamsForExecutable = staticModeParamsForExecutable;
      this.ccCompilationOutputs = ccCompilationOutputs;
    }

    public CcCompilationOutputs getCcCompilationOutputs(RuleContext ruleContext) {
      checkRestrictedUsage(ruleContext);
      return ccCompilationOutputs;
    }

    public CcLinkParams getStaticModeParamsForExecutable(RuleContext ruleContext) {
      checkRestrictedUsage(ruleContext);
      return staticModeParamsForExecutable;
    }

    private void checkRestrictedUsage(RuleContext ruleContext) {
      Rule rule = ruleContext.getRule();
      if (rule.getRuleClassObject().isSkylark()
          || (!rule.getRuleClass().equals("java_binary")
              && !rule.getRuleClass().equals("java_test")
              && !rule.getRuleClass().equals("py_binary")
              && !rule.getRuleClass().equals("py_test"))) {
        throw new IllegalStateException(RESTRICTION_ERROR_MESSAGE + rule.getRuleClass());
      }
    }

    /** Provider class for {@link CcLauncherInfo} objects. */
    public static class Provider extends BuiltinProvider<CcLauncherInfo> {
      private Provider() {
        super(PROVIDER_NAME, CcLauncherInfo.class);
      }
    }
  }

  private static Runfiles collectRunfiles(
      RuleContext ruleContext,
      FeatureConfiguration featureConfiguration,
      CcToolchainProvider toolchain,
      CcLinkingOutputs linkingOutputs,
      CcLinkingOutputs ccLibraryLinkingOutputs,
      CcCompilationContext ccCompilationContext,
      Link.LinkingMode linkingMode,
      NestedSet<Artifact> filesToBuild,
      Iterable<Artifact> fakeLinkerInputs,
      boolean fake,
      ImmutableSet<CppSource> cAndCppSources,
      boolean linkCompileOutputSeparately) {
    Runfiles.Builder builder =
        new Runfiles.Builder(
            ruleContext.getWorkspaceName(),
            ruleContext.getConfiguration().legacyExternalRunfiles());
    Function<TransitiveInfoCollection, Runfiles> runfilesMapping =
        CppHelper.runfilesFunction(ruleContext, linkingMode != Link.LinkingMode.DYNAMIC);
    builder.addTransitiveArtifacts(filesToBuild);
    // Add the shared libraries to the runfiles. This adds any shared libraries that are in the
    // srcs of this target.
    builder.addArtifacts(linkingOutputs.getLibrariesForRunfiles(true));
    builder.addRunfiles(ruleContext, RunfilesProvider.DEFAULT_RUNFILES);
    // TODO(plf): Why do we need .so files produced by cc_library in data dependencies of cc_binary?
    // This can probably be removed safely.
    for (TransitiveInfoCollection transitiveInfoCollection :
        ruleContext.getPrerequisites("data", Mode.DONT_CHECK)) {
      builder.merge(
          CppHelper.runfilesFunction(ruleContext, /* linkingStatically= */ true)
              .apply(transitiveInfoCollection));
      builder.merge(
          CppHelper.runfilesFunction(ruleContext, /* linkingStatically= */ false)
              .apply(transitiveInfoCollection));
    }
    builder.add(ruleContext, runfilesMapping);
    // Add the C++ runtime libraries if linking them dynamically.
    if (linkingMode == Link.LinkingMode.DYNAMIC) {
      builder.addTransitiveArtifacts(toolchain.getDynamicRuntimeLinkInputs(featureConfiguration));
    }
    if (linkCompileOutputSeparately) {
      builder.addArtifacts(
          LinkerInputs.toLibraryArtifacts(ccLibraryLinkingOutputs.getDynamicLibrariesForRuntime()));
    }
    // For cc_binary and cc_test rules, there is an implicit dependency on
    // the malloc library package, which is specified by the "malloc" attribute.
    // As the BUILD encyclopedia says, the "malloc" attribute should be ignored
    // if linkshared=1.
    boolean linkshared = isLinkShared(ruleContext);
    if (!linkshared) {
      TransitiveInfoCollection malloc = CppHelper.mallocForTarget(ruleContext);
      builder.addTarget(malloc, RunfilesProvider.DEFAULT_RUNFILES);
      builder.addTarget(malloc, runfilesMapping);
    }

    if (fake) {
      // Add the object files, libraries, and linker scripts that are used to
      // link this executable.
      builder.addSymlinksToArtifacts(Iterables.filter(fakeLinkerInputs, Artifact.MIDDLEMAN_FILTER));
      // The crosstool inputs for the link action are not sufficient; we also need the crosstool
      // inputs for compilation. Node that these cannot be middlemen because Runfiles does not
      // know how to expand them.
      builder.addTransitiveArtifacts(toolchain.getCrosstool());
      builder.addTransitiveArtifacts(toolchain.getLibcLink());
      // Add the sources files that are used to compile the object files.
      // We add the headers in the transitive closure and our own sources in the srcs
      // attribute. We do not provide the auxiliary inputs, because they are only used when we
      // do FDO compilation, and cc_fake_binary does not support FDO.
      ImmutableSet.Builder<Artifact> sourcesBuilder = ImmutableSet.<Artifact>builder();
      for (CppSource cppSource : cAndCppSources) {
        sourcesBuilder.add(cppSource.getSource());
      }
      builder.addSymlinksToArtifacts(sourcesBuilder.build());
      builder.addSymlinksToArtifacts(ccCompilationContext.getDeclaredIncludeSrcs());
      // Add additional files that are referenced from the compile command, like module maps
      // or header modules.
      builder.addSymlinksToArtifacts(ccCompilationContext.getAdditionalInputs());
      builder.addSymlinksToArtifacts(
          ccCompilationContext.getTransitiveModules(usePic(ruleContext, toolchain)));
    }
    return builder.build();
  }

  @Override
  public ConfiguredTarget create(RuleContext context)
      throws InterruptedException, RuleErrorException, ActionConflictException {
    return CcBinary.init(semantics, context, /*fake =*/ false);
  }

  public static ConfiguredTarget init(CppSemantics semantics, RuleContext ruleContext, boolean fake)
      throws InterruptedException, RuleErrorException, ActionConflictException {
    CppHelper.checkAllowedDeps(ruleContext);

    ruleContext.checkSrcsSamePackage(true);

    CcCommon common = new CcCommon(ruleContext);
    CcToolchainProvider ccToolchain = common.getToolchain();

      ImmutableMap.Builder<String, String> toolchainMakeVariables = ImmutableMap.builder();
      ccToolchain.addGlobalMakeVariables(toolchainMakeVariables);
      ruleContext.initConfigurationMakeVariableContext(
          new MapBackedMakeVariableSupplier(toolchainMakeVariables.build()),
          new CcFlagsSupplier(ruleContext));

    CppConfiguration cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
    PrecompiledFiles precompiledFiles = new PrecompiledFiles(ruleContext);
    LinkTargetType linkType =
        isLinkShared(ruleContext) ? LinkTargetType.DYNAMIC_LIBRARY : LinkTargetType.EXECUTABLE;

    semantics.validateAttributes(ruleContext);
    if (ruleContext.hasErrors()) {
      return null;
    }

    // if cc_binary includes "linkshared=1", then gcc will be invoked with
    // linkopt "-shared", which causes the result of linking to be a shared
    // library. In this case, the name of the executable target should end
    // in ".so" or "dylib" or ".dll".
    Artifact binary;
    PathFragment binaryPath = PathFragment.create(ruleContext.getTarget().getName());
    if (!isLinkShared(ruleContext)) {
      binary =
          CppHelper.getLinkedArtifact(
              ruleContext, ccToolchain, ruleContext.getConfiguration(), LinkTargetType.EXECUTABLE);
    } else {
      binary = ruleContext.getBinArtifact(binaryPath);
    }

    if (isLinkShared(ruleContext)
        && !CppFileTypes.SHARED_LIBRARY.matches(binary.getFilename())
        && !CppFileTypes.VERSIONED_SHARED_LIBRARY.matches(binary.getFilename())) {
      ruleContext.attributeError("linkshared", "'linkshared' used in non-shared library");
      return null;
    }

    LinkingMode linkingMode = getLinkStaticness(ruleContext, cppConfiguration);
    ImmutableSet.Builder<String> requestedFeaturesBuilder = new ImmutableSet.Builder<>();
    requestedFeaturesBuilder
        .addAll(ruleContext.getFeatures())
        .add(linkingMode == Link.LinkingMode.DYNAMIC ? DYNAMIC_LINKING_MODE : STATIC_LINKING_MODE);
    if (fake) {
      requestedFeaturesBuilder.add(CppRuleClasses.IS_CC_FAKE_BINARY);
    }

    FdoProvider fdoProvider = common.getFdoProvider();
    FeatureConfiguration featureConfiguration =
        CcCommon.configureFeaturesOrReportRuleError(
            ruleContext,
            requestedFeaturesBuilder.build(),
            /* unsupportedFeatures= */ ruleContext.getDisabledFeatures(),
            ccToolchain);

    CcCompilationHelper compilationHelper =
        new CcCompilationHelper(
                ruleContext, semantics, featureConfiguration, ccToolchain, fdoProvider)
            .fromCommon(common, /* additionalCopts= */ ImmutableList.of())
            .addPrivateHeaders(common.getPrivateHeaders())
            .addSources(common.getSources())
            .addDeps(ImmutableList.of(CppHelper.mallocForTarget(ruleContext)))
            .setFake(fake)
            .addPrecompiledFiles(precompiledFiles);
    CompilationInfo compilationInfo = compilationHelper.compile();
    CcCompilationContext ccCompilationContext = compilationInfo.getCcCompilationContext();
    CcCompilationOutputs ccCompilationOutputs = compilationInfo.getCcCompilationOutputs();

    // Allows the dynamic library generated for code of default dynamic mode targets to be linked
    // separately. The main use case for default dynamic mode is the cc_test rule. The same behavior
    // can also be enabled specifically for tests with an experimental flag.
    // TODO(meikeb): Retire the experimental flag by end of 2018.
    boolean linkCompileOutputSeparately =
        (ruleContext.isTestTarget()
                && cppConfiguration.getLinkCompileOutputSeparately()
                && linkingMode == LinkingMode.DYNAMIC)
            || (cppConfiguration.getDynamicModeFlag() == DynamicMode.DEFAULT
                && ruleContext.getDisabledFeatures().contains(STATIC_LINK_SRCS));
    // When linking the object files directly into the resulting binary, we do not need
    // library-level link outputs; thus, we do not let CcCompilationHelper produce link outputs
    // (either shared object files or archives) for a non-library link type [*], and add
    // the object files explicitly in determineLinkerArguments.
    //
    // When linking the object files into their own library, we want CcCompilationHelper to
    // take care of creating the library link outputs for us, so we need to set the link
    // type to STATIC_LIBRARY.
    //
    // [*] The only library link type is STATIC_LIBRARY. EXECUTABLE specifies a normal
    // cc_binary output, while DYNAMIC_LIBRARY is a cc_binary rules that produces an
    // output matching a shared object, for example cc_binary(name="foo.so", ...) on linux.
    CcLinkingOutputs ccLinkingOutputs = CcLinkingOutputs.EMPTY;
    if (linkCompileOutputSeparately && !ccCompilationOutputs.isEmpty()) {
      CcLinkingHelper linkingHelper =
          new CcLinkingHelper(
                  ruleContext,
                  semantics,
                  featureConfiguration,
                  ccToolchain,
                  fdoProvider,
                  ruleContext.getConfiguration())
              .fromCommon(common)
              .addDeps(ImmutableList.of(CppHelper.mallocForTarget(ruleContext)))
              .emitInterfaceSharedObjects(true)
              .setAlwayslink(false);
      ccLinkingOutputs = linkingHelper.link(ccCompilationOutputs);
    }

    CcLinkParams linkParams =
        collectCcLinkParams(
            ruleContext,
            linkingMode != Link.LinkingMode.DYNAMIC,
            isLinkShared(ruleContext),
            common.getLinkopts());

    Artifact generatedDefFile = null;
    Artifact customDefFile = null;
    if (isLinkShared(ruleContext)) {
      if (featureConfiguration.isEnabled(CppRuleClasses.TARGETS_WINDOWS)) {
        ImmutableList.Builder<Artifact> objectFiles = ImmutableList.builder();
        objectFiles.addAll(ccCompilationOutputs.getObjectFiles(false));
        for (LibraryToLink library : linkParams.getLibraries()) {
          if (library.containsObjectFiles()
              && library.getArtifactCategory() != ArtifactCategory.DYNAMIC_LIBRARY
              && library.getArtifactCategory() != ArtifactCategory.INTERFACE_LIBRARY) {
            objectFiles.addAll(library.getObjectFiles());
          }
        }
        generatedDefFile =
            CppHelper.createDefFileActions(
                ruleContext,
                ruleContext.getPrerequisiteArtifact("$def_parser", Mode.HOST),
                objectFiles.build(),
                binary.getFilename());
        customDefFile = common.getWinDefFile();
      }
    }

    boolean usePic = usePic(ruleContext, ccToolchain);

    // On Windows, if GENERATE_PDB_FILE feature is enabled
    // then a pdb file will be built along with the executable.
    Artifact pdbFile = null;
    if (featureConfiguration.isEnabled(CppRuleClasses.GENERATE_PDB_FILE)) {
      pdbFile = ruleContext.getRelatedArtifact(binary.getRootRelativePath(), ".pdb");
    }

    Pair<CcLinkingOutputs, Pair<CcLinkingInfo, CcCompilationOutputs>>
        ccLinkingOutputsAndCcLinkingInfo =
            createTransitiveLinkingActions(
                ruleContext,
                ccToolchain,
                featureConfiguration,
                fdoProvider,
                common,
                precompiledFiles,
                ccCompilationOutputs,
                ccLinkingOutputs,
                ccCompilationContext,
                fake,
                binary,
                linkParams,
                linkCompileOutputSeparately,
                semantics,
                linkingMode,
                cppConfiguration,
                linkType,
                pdbFile,
                generatedDefFile,
                customDefFile);

    CcLinkingOutputs ccLinkingOutputsBinary = ccLinkingOutputsAndCcLinkingInfo.first;

    CcLauncherInfo ccLauncherInfo =
        new CcLauncherInfo(
            ccLinkingOutputsAndCcLinkingInfo.second.first.getStaticModeParamsForExecutable(),
            ccLinkingOutputsAndCcLinkingInfo.second.second);

    LibraryToLink outputLibrary = null;
    List<LibraryToLink> dynamicLibrariesForRuntime =
        ccLinkingOutputsBinary.getDynamicLibrariesForRuntime();
    if (!dynamicLibrariesForRuntime.isEmpty()) {
      Preconditions.checkState(dynamicLibrariesForRuntime.size() == 1);
      outputLibrary = dynamicLibrariesForRuntime.get(0);
    }
    Iterable<Artifact> fakeLinkerInputs =
        fake ? ccLinkingOutputsBinary.getLinkActionInputs() : ImmutableList.<Artifact>of();
    CcLinkingOutputs.Builder linkingOutputsBuilder = new CcLinkingOutputs.Builder();
    if (isLinkShared(ruleContext)) {
      linkingOutputsBuilder.addDynamicLibraryForLinking(outputLibrary);
      linkingOutputsBuilder.addDynamicLibraryForRuntime(outputLibrary);
    }
    // Also add all shared libraries from srcs.
    for (Artifact library : precompiledFiles.getSharedLibraries()) {
      Artifact symlink = common.getDynamicLibrarySymlink(library, true);
      LibraryToLink symlinkLibrary = LinkerInputs.solibLibraryToLink(
          symlink, library, CcLinkingOutputs.libraryIdentifierOf(library));
      linkingOutputsBuilder.addDynamicLibraryForLinking(symlinkLibrary);
      linkingOutputsBuilder.addDynamicLibraryForRuntime(symlinkLibrary);
    }
    CcLinkingOutputs linkingOutputs = linkingOutputsBuilder.build();
    NestedSet<Artifact> filesToBuild = NestedSetBuilder.create(Order.STABLE_ORDER, binary);

    // Create the stripped binary, but don't add it to filesToBuild; it's only built when requested.
    Artifact strippedFile = ruleContext.getImplicitOutputArtifact(
        CppRuleClasses.CC_BINARY_STRIPPED);
    CppHelper.createStripAction(
        ruleContext, ccToolchain, cppConfiguration, binary, strippedFile, featureConfiguration);

    DwoArtifactsCollector dwoArtifacts =
        collectTransitiveDwoArtifacts(
            ruleContext,
            ccCompilationOutputs,
            linkingMode,
            ccToolchain.useFission(),
            usePic,
            ccLinkingOutputsBinary.getAllLtoArtifacts());
    Artifact dwpFile =
        ruleContext.getImplicitOutputArtifact(CppRuleClasses.CC_BINARY_DEBUG_PACKAGE);
    createDebugPackagerActions(ruleContext, ccToolchain, dwpFile, dwoArtifacts);

    // The debug package should include the dwp file only if it was explicitly requested.
    Artifact explicitDwpFile = dwpFile;
    if (!ccToolchain.useFission()) {
      explicitDwpFile = null;
    } else {
      // For cc_test rules, include the dwp in the runfiles if Fission is enabled and the test was
      // built statically.
      if (TargetUtils.isTestRule(ruleContext.getRule())
          && linkingMode != Link.LinkingMode.DYNAMIC
          && ccToolchain.useFission()
          && cppConfiguration.buildTestDwpIsActivated()) {
        filesToBuild = NestedSetBuilder.fromNestedSet(filesToBuild).add(dwpFile).build();
      }
    }

    // If the binary is linked dynamically and COPY_DYNAMIC_LIBRARIES_TO_BINARY is enabled, collect
    // all the dynamic libraries we need at runtime. Then copy these libraries next to the binary.
    if (featureConfiguration.isEnabled(CppRuleClasses.COPY_DYNAMIC_LIBRARIES_TO_BINARY)) {
      filesToBuild =
          NestedSetBuilder.fromNestedSet(filesToBuild)
              .addAll(
                  createDynamicLibrariesCopyActions(
                      ruleContext, linkParams.getDynamicLibrariesForRuntime()))
              .build();
    }

    // TODO(bazel-team): Do we need to put original shared libraries (along with
    // mangled symlinks) into the RunfilesSupport object? It does not seem
    // logical since all symlinked libraries will be linked anyway and would
    // not require manual loading but if we do, then we would need to collect
    // their names and use a different constructor below.
    Runfiles runfiles =
        collectRunfiles(
            ruleContext,
            featureConfiguration,
            ccToolchain,
            linkingOutputs,
            ccLinkingOutputs,
            ccCompilationContext,
            linkingMode,
            filesToBuild,
            fakeLinkerInputs,
            fake,
            compilationHelper.getCompilationUnitSources(),
            linkCompileOutputSeparately);
    RunfilesSupport runfilesSupport = RunfilesSupport.withExecutable(ruleContext, runfiles, binary);

    RuleConfiguredTargetBuilder ruleBuilder = new RuleConfiguredTargetBuilder(ruleContext);
    addTransitiveInfoProviders(
        ruleContext,
        ccToolchain,
        cppConfiguration,
        common,
        ruleBuilder,
        filesToBuild,
        ccCompilationOutputs,
        ccCompilationContext,
        linkingOutputs,
        dwoArtifacts,
        fake);

    // Support test execution on darwin.
    if (ApplePlatform.isApplePlatform(ccToolchain.getTargetCpu())
        && TargetUtils.isTestRule(ruleContext.getRule())) {
      ruleBuilder.addNativeDeclaredProvider(
          new ExecutionInfo(ImmutableMap.of(ExecutionRequirements.REQUIRES_DARWIN, "")));
    }

    // If PDB file is generated by the link action, we add it to pdb_file output group
    if (pdbFile != null) {
      ruleBuilder.addOutputGroup("pdb_file", pdbFile);
    }

    if (generatedDefFile != null) {
      ruleBuilder.addOutputGroup("def_file", generatedDefFile);
    }

    List<LibraryToLink> dynamicLibraryForLinking =
        ccLinkingOutputsBinary.getDynamicLibrariesForLinking();
    if (!dynamicLibraryForLinking.isEmpty()) {
      Preconditions.checkState(dynamicLibraryForLinking.size() == 1);
      ruleBuilder.addOutputGroup(
          "interface_library", dynamicLibraryForLinking.get(0).getOriginalLibraryArtifact());
    }

    return ruleBuilder
        .addProvider(RunfilesProvider.class, RunfilesProvider.simple(runfiles))
        .addProvider(
            DebugPackageProvider.class,
            new DebugPackageProvider(ruleContext.getLabel(), strippedFile, binary, explicitDwpFile))
        .setRunfilesSupport(runfilesSupport, binary)
        .addNativeDeclaredProvider(ccLauncherInfo)
        .addSkylarkTransitiveInfo(CcSkylarkApiProvider.NAME, new CcSkylarkApiProvider())
        .build();
  }

  public static Pair<CcLinkingOutputs, Pair<CcLinkingInfo, CcCompilationOutputs>>
      createTransitiveLinkingActions(
          RuleContext ruleContext,
          CcToolchainProvider ccToolchain,
          FeatureConfiguration featureConfiguration,
          FdoProvider fdoProvider,
          CcCommon common,
          PrecompiledFiles precompiledFiles,
          CcCompilationOutputs ccCompilationOutputs,
          CcLinkingOutputs ccLinkingOutputs,
          CcCompilationContext ccCompilationContext,
          boolean fake,
          Artifact binary,
          CcLinkParams linkParams,
          boolean linkCompileOutputSeparately,
          CppSemantics cppSemantics,
          LinkingMode linkingMode,
          CppConfiguration cppConfiguration,
          LinkTargetType linkType,
          Artifact pdbFile,
          Artifact generatedDefFile,
          Artifact customDefFile)
          throws InterruptedException, RuleErrorException {
    CcCompilationOutputs.Builder ccCompilationOutputsBuilder =
        new CcCompilationOutputs.Builder()
            .addPicObjectFiles(ccCompilationOutputs.getObjectFiles(/* usePic= */ true))
            .addObjectFiles(ccCompilationOutputs.getObjectFiles(/* usePic= */ false));
    for (Map.Entry<Artifact, Artifact> entry :
        ccCompilationOutputs.getLtoBitcodeFiles().entrySet()) {
      ccCompilationOutputsBuilder.addLtoBitcodeFile(entry.getKey(), entry.getValue());
    }
    CcCompilationOutputs ccCompilationOutputsWithOnlyObjects = ccCompilationOutputsBuilder.build();
    CcLinkingHelper ccLinkingHelper =
        new CcLinkingHelper(
            ruleContext,
            cppSemantics,
            featureConfiguration,
            ccToolchain,
            fdoProvider,
            ruleContext.getConfiguration());

    CcLinkParams.Builder ccLinkParamsBuilder = CcLinkParams.builder();
    ccLinkParamsBuilder.addTransitiveArgs(linkParams);

    if (linkCompileOutputSeparately) {
      for (LibraryToLink library : ccLinkingOutputs.getDynamicLibrariesForLinking()) {
        ccLinkParamsBuilder.addLibrary(library);
      }
      ccCompilationOutputsWithOnlyObjects = new CcCompilationOutputs.Builder().build();
    }

    // Determine the libraries to link in.
    // First libraries from srcs. Shared library artifacts here are substituted with mangled symlink
    // artifacts generated by getDynamicLibraryLink(). This is done to minimize number of -rpath
    // entries during linking process.
    for (Artifact library : precompiledFiles.getLibraries()) {
      if (Link.SHARED_LIBRARY_FILETYPES.matches(library.getFilename())) {
        ccLinkParamsBuilder.addLibrary(
            LinkerInputs.solibLibraryToLink(
                common.getDynamicLibrarySymlink(library, true),
                library,
                CcLinkingOutputs.libraryIdentifierOf(library)));
      } else if (Link.LINK_LIBRARY_FILETYPES.matches(library.getFilename())) {
        ccLinkParamsBuilder.addLibrary(
            LinkerInputs.precompiledLibraryToLink(
                library, ArtifactCategory.ALWAYSLINK_STATIC_LIBRARY));
      } else if (Link.ARCHIVE_FILETYPES.matches(library.getFilename())) {
        ccLinkParamsBuilder.addLibrary(
            LinkerInputs.precompiledLibraryToLink(library, ArtifactCategory.STATIC_LIBRARY));
      } else {
        throw new IllegalStateException();
      }
    }

    if (linkingMode != Link.LinkingMode.DYNAMIC
        && !cppConfiguration.disableEmittingStaticLibgcc()) {
      // Only force a static link of libgcc if static runtime linking is enabled (which
      // can't be true if runtimeInputs is empty).
      // TODO(bazel-team): Move this to CcToolchain.
      if (!ccToolchain.getStaticRuntimeLinkInputs(featureConfiguration).isEmpty()) {
        ccLinkParamsBuilder.addLinkOpts(ImmutableList.of("-static-libgcc"));
      }
    }

    ccLinkParamsBuilder
        .addNonCodeInputs(ccCompilationContext.getTransitiveCompilationPrerequisites())
        .addNonCodeInputs(common.getLinkerScripts());

    CcLinkParams ccLinkParams = ccLinkParamsBuilder.build();
    CcLinkingInfo.Builder ccLinkingInfo = CcLinkingInfo.Builder.create();
    ccLinkingInfo.setStaticModeParamsForDynamicLibrary(ccLinkParams);
    ccLinkingInfo.setStaticModeParamsForExecutable(ccLinkParams);
    ccLinkingInfo.setDynamicModeParamsForDynamicLibrary(ccLinkParams);
    ccLinkingInfo.setDynamicModeParamsForExecutable(ccLinkParams);

    ccLinkingHelper
        .addCcLinkingInfos(ImmutableList.of(ccLinkingInfo.build()))
        .setUseTestOnlyFlags(ruleContext.isTestTarget())
        .setShouldCreateStaticLibraries(false)
        .setLinkingMode(linkingMode)
        .setDynamicLinkType(linkType)
        .setLinkerOutputArtifact(binary)
        .setNeverLink(true)
        .emitInterfaceSharedObjects(
            isLinkShared(ruleContext)
                && featureConfiguration.isEnabled(CppRuleClasses.TARGETS_WINDOWS)
                && CppHelper.useInterfaceSharedObjects(cppConfiguration, ccToolchain))
        .setPdbFile(pdbFile)
        .setFake(fake);

    if (customDefFile != null) {
      ccLinkingHelper.setDefFile(customDefFile);
    } else if (CppHelper.shouldUseGeneratedDefFile(ruleContext, featureConfiguration)) {
      ccLinkingHelper.setDefFile(generatedDefFile);
    }

    return Pair.of(
        ccLinkingHelper.link(ccCompilationOutputsWithOnlyObjects),
        Pair.of(ccLinkingInfo.build(), ccCompilationOutputsWithOnlyObjects));
  }

  /**
   * Returns "true" if the {@code linkshared} attribute exists and is set.
   */
  private static final boolean isLinkShared(RuleContext context) {
    return context.attributes().has("linkshared", Type.BOOLEAN)
        && context.attributes().get("linkshared", Type.BOOLEAN);
  }

  private static final LinkingMode getLinkStaticness(
      RuleContext context, CppConfiguration cppConfiguration) {
    if (cppConfiguration.getDynamicModeFlag() == DynamicMode.FULLY) {
      return LinkingMode.DYNAMIC;
    } else if (cppConfiguration.getDynamicModeFlag() == DynamicMode.OFF
        || context.attributes().get("linkstatic", Type.BOOLEAN)) {
      return LinkingMode.STATIC;
    } else {
      return LinkingMode.DYNAMIC;
    }
  }

  /**
   * Collects .dwo artifacts either transitively or directly, depending on the link type.
   *
   * <p>For a cc_binary, we only include the .dwo files corresponding to the .o files that are
   * passed into the link. For static linking, this includes all transitive dependencies. But for
   * dynamic linking, dependencies are separately linked into their own shared libraries, so we
   * don't need them here.
   */
  private static DwoArtifactsCollector collectTransitiveDwoArtifacts(
      RuleContext context,
      CcCompilationOutputs compilationOutputs,
      Link.LinkingMode linkingMode,
      boolean generateDwo,
      boolean ltoBackendArtifactsUsePic,
      Iterable<LtoBackendArtifacts> ltoBackendArtifacts) {
    if (linkingMode == LinkingMode.DYNAMIC) {
      return DwoArtifactsCollector.directCollector(
          compilationOutputs, generateDwo, ltoBackendArtifactsUsePic, ltoBackendArtifacts);
    } else {
      return CcCommon.collectTransitiveDwoArtifacts(
          context, compilationOutputs, generateDwo, ltoBackendArtifactsUsePic, ltoBackendArtifacts);
    }
  }

  @VisibleForTesting
  public static Iterable<Artifact> getDwpInputs(
      RuleContext context,
      CcToolchainProvider toolchain,
      NestedSet<Artifact> picDwoArtifacts,
      NestedSet<Artifact> dwoArtifacts) {
    return usePic(context, toolchain) ? picDwoArtifacts : dwoArtifacts;
  }

  /**
   * Creates the actions needed to generate this target's "debug info package" (i.e. its .dwp file).
   */
  private static void createDebugPackagerActions(
      RuleContext context,
      CcToolchainProvider toolchain,
      Artifact dwpOutput,
      DwoArtifactsCollector dwoArtifactsCollector) {
    Iterable<Artifact> allInputs =
        getDwpInputs(
            context,
            toolchain,
            dwoArtifactsCollector.getPicDwoArtifacts(),
            dwoArtifactsCollector.getDwoArtifacts());

    // No inputs? Just generate a trivially empty .dwp.
    //
    // Note this condition automatically triggers for any build where fission is disabled.
    // Because rules referencing .dwp targets may be invoked with or without fission, we need
    // to support .dwp generation even when fission is disabled. Since no actual functionality
    // is expected then, an empty file is appropriate.
    if (Iterables.isEmpty(allInputs)) {
      context.registerAction(FileWriteAction.create(context, dwpOutput, "", false));
      return;
    }

    // Get the tool inputs necessary to run the dwp command.
    NestedSet<Artifact> dwpTools = toolchain.getDwp();
    Preconditions.checkState(!dwpTools.isEmpty());

    // We apply a hierarchical action structure to limit the maximum number of inputs to any
    // single action.
    //
    // While the dwp tool consumes .dwo files, it can also consume intermediate .dwp files,
    // allowing us to split a large input set into smaller batches of arbitrary size and order.
    // Aside from the parallelism performance benefits this offers, this also reduces input
    // size requirements: if a.dwo, b.dwo, c.dwo, and e.dwo are each 1 KB files, we can apply
    // two intermediate actions DWP(a.dwo, b.dwo) --> i1.dwp and DWP(c.dwo, e.dwo) --> i2.dwp.
    // When we then apply the final action DWP(i1.dwp, i2.dwp) --> finalOutput.dwp, the inputs
    // to this action will usually total far less than 4 KB.
    //
    // The actions form an n-ary tree with n == MAX_INPUTS_PER_DWP_ACTION. The tree is fuller
    // at the leaves than the root, but that both increases parallelism and reduces the final
    // action's input size.
    Packager packager =
        createIntermediateDwpPackagers(context, dwpOutput, toolchain, dwpTools, allInputs, 1);
    packager.spawnAction.setMnemonic("CcGenerateDwp").addOutput(dwpOutput);
    packager.commandLine.addExecPath("-o", dwpOutput);
    context.registerAction(packager.build(context));
  }

  private static class Packager {
    SpawnAction.Builder spawnAction = new SpawnAction.Builder();
    CustomCommandLine.Builder commandLine = CustomCommandLine.builder();

    Action[] build(RuleContext context) {
      spawnAction.addCommandLine(
          commandLine.build(), ParamFileInfo.builder(ParameterFileType.UNQUOTED).build());
      return spawnAction.build(context);
    }
  }

  /**
   * Creates the intermediate actions needed to generate this target's "debug info package" (i.e.
   * its .dwp file).
   */
  private static Packager createIntermediateDwpPackagers(
      RuleContext context,
      Artifact dwpOutput,
      CcToolchainProvider toolchain,
      NestedSet<Artifact> dwpTools,
      Iterable<Artifact> inputs,
      int intermediateDwpCount) {
    List<Packager> packagers = new ArrayList<>();

    // Step 1: generate our batches. We currently break into arbitrary batches of fixed maximum
    // input counts, but we can always apply more intelligent heuristics if the need arises.
    Packager currentPackager = newDwpAction(toolchain, dwpTools);
    int inputsForCurrentPackager = 0;

    for (Artifact dwoInput : inputs) {
      if (inputsForCurrentPackager == MAX_INPUTS_PER_DWP_ACTION) {
        packagers.add(currentPackager);
        currentPackager = newDwpAction(toolchain, dwpTools);
        inputsForCurrentPackager = 0;
      }
      currentPackager.spawnAction.addInput(dwoInput);
      currentPackager.commandLine.addExecPath(dwoInput);
      inputsForCurrentPackager++;
    }
    packagers.add(currentPackager);
    // Step 2: given the batches, create the actions.
    if (packagers.size() > 1) {
      // If we have multiple batches, make them all intermediate actions, then pipe their outputs
      // into an additional level.
      List<Artifact> intermediateOutputs = new ArrayList<>();

      for (Packager packager : packagers) {
        Artifact intermediateOutput =
            getIntermediateDwpFile(context, dwpOutput, intermediateDwpCount++);
        packager.spawnAction.setMnemonic("CcGenerateIntermediateDwp").addOutput(intermediateOutput);
        packager.commandLine.addExecPath("-o", intermediateOutput);
        context.registerAction(packager.build(context));
        intermediateOutputs.add(intermediateOutput);
      }
      return createIntermediateDwpPackagers(
          context, dwpOutput, toolchain, dwpTools, intermediateOutputs, intermediateDwpCount);
    }
    return Iterables.getOnlyElement(packagers);
  }

  /**
   * Create the actions to symlink/copy execution dynamic libraries to binary directory so that they
   * are available at runtime.
   *
   * @param dynamicLibrariesForRuntime The libraries to be copied.
   * @return The result artifacts of the copies.
   */
  private static ImmutableList<Artifact> createDynamicLibrariesCopyActions(
      RuleContext ruleContext, NestedSet<Artifact> dynamicLibrariesForRuntime) {
    ImmutableList.Builder<Artifact> result = ImmutableList.builder();
    for (Artifact target : dynamicLibrariesForRuntime) {
      if (!ruleContext.getLabel().getPackageName().equals(target.getOwner().getPackageName())) {
        // SymlinkAction on file is actually copy on Windows.
        Artifact copy = ruleContext.getBinArtifact(target.getFilename());
        ruleContext.registerAction(SymlinkAction.toArtifact(
            ruleContext.getActionOwner(), target, copy, "Copying Execution Dynamic Library"));
        result.add(copy);
      }
    }
    return result.build();
  }

  /**
   * Returns a new SpawnAction builder for generating dwp files, pre-initialized with standard
   * settings.
   */
  private static Packager newDwpAction(
      CcToolchainProvider toolchain, NestedSet<Artifact> dwpTools) {
    Packager packager = new Packager();
    packager
        .spawnAction
        .addTransitiveInputs(dwpTools)
        .setExecutable(toolchain.getToolPathFragment(Tool.DWP));
    return packager;
  }

  /**
   * Creates an intermediate dwp file keyed off the name and path of the final output.
   */
  private static Artifact getIntermediateDwpFile(RuleContext ruleContext, Artifact dwpOutput,
      int orderNumber) {
    PathFragment outputPath = dwpOutput.getRootRelativePath();
    PathFragment intermediatePath =
        FileSystemUtils.appendWithoutExtension(outputPath, "-" + orderNumber);
    return ruleContext.getPackageRelativeArtifact(
        PathFragment.create(INTERMEDIATE_DWP_DIR + "/" + intermediatePath.getPathString()),
        dwpOutput.getRoot());
  }

  /**
   * Collect link parameters from the transitive closure.
   */
  private static CcLinkParams collectCcLinkParams(RuleContext context,
      boolean linkingStatically, boolean linkShared, List<String> linkopts) {
    CcLinkParams.Builder builder = CcLinkParams.builder(linkingStatically, linkShared);

    builder.addCcLibrary(context);
    if (!isLinkShared(context)) {
      builder.addTransitiveTarget(CppHelper.mallocForTarget(context));
    }
    builder.addLinkOpts(linkopts);
    return builder.build();
  }

  private static void addTransitiveInfoProviders(
      RuleContext ruleContext,
      CcToolchainProvider toolchain,
      CppConfiguration cppConfiguration,
      CcCommon common,
      RuleConfiguredTargetBuilder builder,
      NestedSet<Artifact> filesToBuild,
      CcCompilationOutputs ccCompilationOutputs,
      CcCompilationContext ccCompilationContext,
      CcLinkingOutputs linkingOutputs,
      DwoArtifactsCollector dwoArtifacts,
      boolean fake) {
    List<Artifact> instrumentedObjectFiles = new ArrayList<>();
    instrumentedObjectFiles.addAll(ccCompilationOutputs.getObjectFiles(false));
    instrumentedObjectFiles.addAll(ccCompilationOutputs.getObjectFiles(true));
    InstrumentedFilesInfo instrumentedFilesProvider =
        common.getInstrumentedFilesProvider(
            instrumentedObjectFiles,
            !TargetUtils.isTestRule(ruleContext.getRule()) && !fake,
            ccCompilationContext.getVirtualToOriginalHeaders());

    NestedSet<Artifact> headerTokens =
        CcCompilationHelper.collectHeaderTokens(ruleContext, ccCompilationOutputs);
    NestedSet<Artifact> filesToCompile =
        ccCompilationOutputs.getFilesToCompile(
            cppConfiguration.processHeadersInDependencies(), toolchain.usePicForDynamicLibraries());

    builder
        .setFilesToBuild(filesToBuild)
        .addNativeDeclaredProvider(
            CcInfo.builder().setCcCompilationContext(ccCompilationContext).build())
        .addProvider(
            CcNativeLibraryProvider.class,
            new CcNativeLibraryProvider(
                collectTransitiveCcNativeLibraries(
                    ruleContext, linkingOutputs.getDynamicLibrariesForLinking())))
        .addNativeDeclaredProvider(instrumentedFilesProvider)
        .addProvider(
            CppDebugFileProvider.class,
            new CppDebugFileProvider(
                dwoArtifacts.getDwoArtifacts(), dwoArtifacts.getPicDwoArtifacts()))
        .addOutputGroup(OutputGroupInfo.TEMP_FILES, ccCompilationOutputs.getTemps())
        .addOutputGroup(OutputGroupInfo.FILES_TO_COMPILE, filesToCompile)
        // For CcBinary targets, we only want to ensure that we process headers in dependencies and
        // thus only add header tokens to HIDDEN_TOP_LEVEL. If we add all HIDDEN_TOP_LEVEL artifacts
        // from dependent CcLibrary targets, we'd be building .pic.o files in nopic builds.
        .addOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL, headerTokens)
        .addOutputGroup(
            OutputGroupInfo.COMPILATION_PREREQUISITES,
            CcCommon.collectCompilationPrerequisites(ruleContext, ccCompilationContext));

    CppHelper.maybeAddStaticLinkMarkerProvider(builder, ruleContext);
  }

  private static NestedSet<LinkerInput> collectTransitiveCcNativeLibraries(
      RuleContext ruleContext,
      List<? extends LinkerInput> dynamicLibraries) {
    NestedSetBuilder<LinkerInput> builder = NestedSetBuilder.linkOrder();
    builder.addAll(dynamicLibraries);
    for (CcNativeLibraryProvider dep :
      ruleContext.getPrerequisites("deps", Mode.TARGET, CcNativeLibraryProvider.class)) {
      builder.addTransitive(dep.getTransitiveCcNativeLibraries());
    }
    return builder.build();
  }

  private static boolean usePic(RuleContext ruleContext, CcToolchainProvider ccToolchainProvider) {
    if (isLinkShared(ruleContext)) {
      return ccToolchainProvider.usePicForDynamicLibraries();
    } else {
      return CppHelper.usePicForBinaries(ruleContext, ccToolchainProvider);
    }
  }
}