src/main/java/com/google/devtools/build/lib/rules/cpp/CcLinkParams.java - bazel - Git at Google

 // 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 com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
 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.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.rules.cpp.LinkerInputs.LibraryToLink;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.VisibleForSerialization;
 import java.util.Collection;
 import java.util.Objects;
 import javax.annotation.Nullable;

 /**
  * Parameters to be passed to the linker.
  *
  * <p>The parameters concerned are the link options (strings) passed to the linker, linkstamps, a
  * list of libraries to be linked in, and a list of libraries to build at link time.
  *
  * <p>Items in the collections are stored in nested sets. Link options and libraries are stored in
  * link order (preorder) and linkstamps are sorted.
  */
 @AutoCodec
 public final class CcLinkParams {
   /**
    * A list of link options contributed by a single configured target.
    *
    * <p><b>WARNING:</b> Do not implement {@code #equals()} in the obvious way. This class must be
    * checked for equality by object identity because otherwise if two configured targets contribute
    * the same link options, they will be de-duplicated, which is not the desirable behavior.
    */
   @AutoCodec
   @Immutable
   public static final class LinkOptions {
     private final ImmutableList<String> linkOptions;

     @VisibleForSerialization
     LinkOptions(Iterable<String> linkOptions) {
       this.linkOptions = ImmutableList.copyOf(linkOptions);
     }

     public ImmutableList<String> get() {
       return linkOptions;
     }

     public static LinkOptions of(Iterable<String> linkOptions) {
       return new LinkOptions(linkOptions);
     }
   }

   private final NestedSet<LinkOptions> linkOpts;
   private final NestedSet<Linkstamp> linkstamps;
   private final NestedSet<LibraryToLink> libraries;
   private final NestedSet<Artifact> executionDynamicLibraries;
   private final ExtraLinkTimeLibraries extraLinkTimeLibraries;
   private final NestedSet<Artifact> nonCodeInputs;

   @AutoCodec.Instantiator
   @VisibleForSerialization
   CcLinkParams(
       NestedSet<LinkOptions> linkOpts,
       NestedSet<Linkstamp> linkstamps,
       NestedSet<LibraryToLink> libraries,
       NestedSet<Artifact> executionDynamicLibraries,
       ExtraLinkTimeLibraries extraLinkTimeLibraries,
       NestedSet<Artifact> nonCodeInputs) {
     this.linkOpts = linkOpts;
     this.linkstamps = linkstamps;
     this.libraries = libraries;
     this.executionDynamicLibraries = executionDynamicLibraries;
     this.extraLinkTimeLibraries = extraLinkTimeLibraries;
     this.nonCodeInputs = nonCodeInputs;
   }

   /**
    * Returns the linkopts
    */
   public NestedSet<LinkOptions> getLinkopts() {
     return linkOpts;
   }

   public ImmutableList<String> flattenedLinkopts() {
     return ImmutableList.copyOf(Iterables.concat(Iterables.transform(linkOpts, LinkOptions::get)));
   }

   /**
    * Returns the linkstamps
    */
   public NestedSet<Linkstamp> getLinkstamps() {
     return linkstamps;
   }

   /**
    * Returns the libraries
    */
   public NestedSet<LibraryToLink> getLibraries() {
     return libraries;
   }

   /**
    * Returns the executionDynamicLibraries.
    */
   public NestedSet<Artifact> getExecutionDynamicLibraries() {
     return executionDynamicLibraries;
   }

   /**
    * The extra link time libraries; will be null if there are no such libraries.
    */
   public @Nullable ExtraLinkTimeLibraries getExtraLinkTimeLibraries() {
     return extraLinkTimeLibraries;
   }

   /**
    * Returns the non-code inputs, e.g. linker scripts; will be null if none.
    */
   public @Nullable NestedSet<Artifact> getNonCodeInputs() {
     return nonCodeInputs;
   }

   public static final Builder builder(boolean linkingStatically, boolean linkShared) {
     return new Builder(linkingStatically, linkShared);
   }

   /**
    * Builder for {@link CcLinkParams}.
    */
   public static final class Builder {

     /**
      * linkingStatically is true when we're linking this target in either FULLY STATIC mode
      * (linkopts=["-static"]) or MOSTLY STATIC mode (linkstatic=1). When this is true, we want to
      * use static versions of any libraries that this target depends on (except possibly system
      * libraries, which are not handled by CcLinkParams). When this is false, we want to use dynamic
      * versions of any libraries that this target depends on.
      */
     private final boolean linkingStatically;

     /**
      * linkShared is true when we're linking with "-shared" (linkshared=1).
      */
     private final boolean linkShared;

     private ImmutableList.Builder<String> localLinkoptsBuilder = ImmutableList.builder();

     private final NestedSetBuilder<LinkOptions> linkOptsBuilder =
         NestedSetBuilder.linkOrder();
     private final NestedSetBuilder<Linkstamp> linkstampsBuilder =
         NestedSetBuilder.compileOrder();
     private final NestedSetBuilder<LibraryToLink> librariesBuilder =
         NestedSetBuilder.linkOrder();
     private final NestedSetBuilder<Artifact> executionDynamicLibrariesBuilder =
         NestedSetBuilder.stableOrder();

     /**
      * A builder for the list of link time libraries.  Most builds
      * won't have any such libraries, so save space by leaving the
      * default as null.
      */
     private ExtraLinkTimeLibraries.Builder extraLinkTimeLibrariesBuilder = null;

     private NestedSetBuilder<Artifact> nonCodeInputsBuilder = null;

     private boolean built = false;

     private Builder(boolean linkingStatically, boolean linkShared) {
       this.linkingStatically = linkingStatically;
       this.linkShared = linkShared;
     }

     /**
      * Builds a {@link CcLinkParams} object.
      */
     public CcLinkParams build() {
       Preconditions.checkState(!built);
       // Not thread-safe, but builders should not be shared across threads.
       built = true;
       ImmutableList<String> localLinkopts = localLinkoptsBuilder.build();
       if (!localLinkopts.isEmpty()) {
         linkOptsBuilder.add(LinkOptions.of(localLinkopts));
       }
       ExtraLinkTimeLibraries extraLinkTimeLibraries = null;
       if (extraLinkTimeLibrariesBuilder != null) {
         extraLinkTimeLibraries = extraLinkTimeLibrariesBuilder.build();
       }
       NestedSet<Artifact> nonCodeInputs = null;
       if (nonCodeInputsBuilder != null) {
         nonCodeInputs = nonCodeInputsBuilder.build();
       }
       return new CcLinkParams(
           linkOptsBuilder.build(),
           linkstampsBuilder.build(),
           librariesBuilder.build(),
           executionDynamicLibrariesBuilder.build(),
           extraLinkTimeLibraries,
           nonCodeInputs);
     }

     public boolean add(CcLinkParamsStore store) {
       if (store != null) {
         CcLinkParams args = store.get(linkingStatically, linkShared);
         addTransitiveArgs(args);
       }
       return store != null;
     }

     /**
      * Includes link parameters from a collection of dependency targets.
      */
     public Builder addTransitiveTargets(Iterable<? extends TransitiveInfoCollection> targets) {
       for (TransitiveInfoCollection target : targets) {
         addTransitiveTarget(target);
       }
       return this;
     }

     /**
      * Includes link parameters from a dependency target.
      *
      * <p>The target should implement {@link CcLinkParamsInfo}. If it does not,
      * the method does not do anything.
      */
     public Builder addTransitiveTarget(TransitiveInfoCollection target) {
       CcLinkingInfo ccLinkingInfo = target.get(CcLinkingInfo.PROVIDER);
       CcLinkParamsInfo ccLinkParamsInfo =
           ccLinkingInfo == null ? null : ccLinkingInfo.getCcLinkParamsInfo();
       return addTransitiveProvider(ccLinkParamsInfo);
     }

     /**
      * Includes link parameters from a dependency target. The target is checked for the given
      * mappings in the order specified, and the first mapping that returns a non-null result is
      * added.
      */
     @SafeVarargs
     public final Builder addTransitiveTarget(TransitiveInfoCollection target,
         Function<TransitiveInfoCollection, CcLinkParamsStore> firstMapping,
         @SuppressWarnings("unchecked") // Java arrays don't preserve generic arguments.
         Function<TransitiveInfoCollection, CcLinkParamsStore>... remainingMappings) {
       if (add(firstMapping.apply(target))) {
         return this;
       }
       for (Function<TransitiveInfoCollection, CcLinkParamsStore> mapping : remainingMappings) {
         if (add(mapping.apply(target))) {
           return this;
         }
       }
       return this;
     }

     /**
      * Includes link parameters from a CcLinkParamsInfo provider.
      */
     public Builder addTransitiveProvider(CcLinkParamsInfo provider) {
       if (provider != null) {
         add(provider.getCcLinkParamsStore());
       }
       return this;
     }

     /**
      * Includes link parameters from the given targets. Each target is checked for the given
      * mappings in the order specified, and the first mapping that returns a non-null result is
      * added.
      */
     @SafeVarargs
     public final Builder addTransitiveTargets(
         Iterable<? extends TransitiveInfoCollection> targets,
         Function<TransitiveInfoCollection, CcLinkParamsStore> firstMapping,
         @SuppressWarnings("unchecked")  // Java arrays don't preserve generic arguments.
         Function<TransitiveInfoCollection, CcLinkParamsStore>... remainingMappings) {
       for (TransitiveInfoCollection target : targets) {
         addTransitiveTarget(target, firstMapping, remainingMappings);
       }
       return this;
     }

     /**
      * Merges the other {@link CcLinkParams} object into this one.
      */
     public Builder addTransitiveArgs(CcLinkParams args) {
       linkOptsBuilder.addTransitive(args.getLinkopts());
       linkstampsBuilder.addTransitive(args.getLinkstamps());
       librariesBuilder.addTransitive(args.getLibraries());
       executionDynamicLibrariesBuilder.addTransitive(args.getExecutionDynamicLibraries());
       if (args.getExtraLinkTimeLibraries() != null) {
         if (extraLinkTimeLibrariesBuilder == null) {
           extraLinkTimeLibrariesBuilder = ExtraLinkTimeLibraries.builder();
         }
         extraLinkTimeLibrariesBuilder.addTransitive(args.getExtraLinkTimeLibraries());
       }
       if (args.getNonCodeInputs() != null) {
         if (nonCodeInputsBuilder == null) {
           nonCodeInputsBuilder = NestedSetBuilder.linkOrder();
         }
         nonCodeInputsBuilder.addTransitive(args.getNonCodeInputs());
       }
       return this;
     }

     /**
      * Adds a collection of link options.
      */
     public Builder addLinkOpts(Collection<String> linkOpts) {
       localLinkoptsBuilder.addAll(linkOpts);
       return this;
     }

     /** Adds a collection of linkstamps. */
     public Builder addLinkstamps(
         NestedSet<Artifact> linkstamps, CcCompilationContext ccCompilationContext) {
       for (Artifact linkstamp : linkstamps) {
         linkstampsBuilder.add(
             new Linkstamp(linkstamp, ccCompilationContext.getDeclaredIncludeSrcs()));
       }
       return this;
     }

     /**
      * Adds a library artifact.
      */
     public Builder addLibrary(LibraryToLink library) {
       librariesBuilder.add(library);
       return this;
     }

     /**
      * Adds a collection of library artifacts.
      */
     public Builder addLibraries(Iterable<LibraryToLink> libraries) {
       librariesBuilder.addAll(libraries);
       return this;
     }

     /** Adds a collection of library artifacts. */
     public Builder addExecutionDynamicLibraries(Iterable<Artifact> libraries) {
       executionDynamicLibrariesBuilder.addAll(libraries);
       return this;
     }

     /**
      * Adds an extra link time library, a library that is actually
      * built at link time.
      */
     public Builder addExtraLinkTimeLibrary(ExtraLinkTimeLibrary e) {
       if (extraLinkTimeLibrariesBuilder == null) {
         extraLinkTimeLibrariesBuilder = ExtraLinkTimeLibraries.builder();
       }
       extraLinkTimeLibrariesBuilder.add(e);
       return this;
     }

     /**
      * Adds a collection of non-code inputs.
      */
     public Builder addNonCodeInputs(Iterable<Artifact> nonCodeInputs) {
       if (nonCodeInputsBuilder == null) {
         nonCodeInputsBuilder = NestedSetBuilder.linkOrder();
       }
       nonCodeInputsBuilder.addAll(nonCodeInputs);
       return this;
     }

     /** Processes typical dependencies of a C/C++ library. */
     public Builder addCcLibrary(RuleContext context) {
       addTransitiveTargets(
           context.getPrerequisites("deps", Mode.TARGET),
           CcLinkParamsInfo.TO_LINK_PARAMS,
           CcSpecificLinkParamsProvider.TO_LINK_PARAMS);
       return this;
     }
   }

   /**
    * A linkstamp that also knows about its declared includes.
    *
    * <p>This object is required because linkstamp files may include other headers which will have to
    * be provided during compilation.
    */
   @AutoCodec
   public static final class Linkstamp {
     private final Artifact artifact;
     private final NestedSet<Artifact> declaredIncludeSrcs;

     @VisibleForSerialization
     Linkstamp(Artifact artifact, NestedSet<Artifact> declaredIncludeSrcs) {
       this.artifact = Preconditions.checkNotNull(artifact);
       this.declaredIncludeSrcs = Preconditions.checkNotNull(declaredIncludeSrcs);
     }

     /**
      * Returns the linkstamp artifact.
      */
     public Artifact getArtifact() {
       return artifact;
     }

     /**
      * Returns the declared includes.
      */
     public NestedSet<Artifact> getDeclaredIncludeSrcs() {
       return declaredIncludeSrcs;
     }

     @Override
     public int hashCode() {
       return Objects.hash(artifact, declaredIncludeSrcs);
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj) {
         return true;
       }
       if (!(obj instanceof Linkstamp)) {
         return false;
       }
       Linkstamp other = (Linkstamp) obj;
       return artifact.equals(other.artifact)
           && declaredIncludeSrcs.equals(other.declaredIncludeSrcs);
     }
   }

   /** Empty CcLinkParams. */
   public static final CcLinkParams EMPTY =
       new CcLinkParams(
           NestedSetBuilder.<LinkOptions>emptySet(Order.LINK_ORDER),
           NestedSetBuilder.<Linkstamp>emptySet(Order.COMPILE_ORDER),
           NestedSetBuilder.<LibraryToLink>emptySet(Order.LINK_ORDER),
           NestedSetBuilder.<Artifact>emptySet(Order.STABLE_ORDER),
           null,
           null);
 }
	// 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 com.google.common.base.Function;
	import com.google.common.base.Preconditions;
	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.Iterables;
	import com.google.devtools.build.lib.actions.Artifact;
	import com.google.devtools.build.lib.analysis.RuleContext;
	import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
	import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
	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.concurrent.ThreadSafety.Immutable;
	import com.google.devtools.build.lib.rules.cpp.LinkerInputs.LibraryToLink;
	import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
	import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.VisibleForSerialization;
	import java.util.Collection;
	import java.util.Objects;
	import javax.annotation.Nullable;

	/**
	* Parameters to be passed to the linker.
	*
	* <p>The parameters concerned are the link options (strings) passed to the linker, linkstamps, a
	* list of libraries to be linked in, and a list of libraries to build at link time.
	*
	* <p>Items in the collections are stored in nested sets. Link options and libraries are stored in
	* link order (preorder) and linkstamps are sorted.
	*/
	@AutoCodec
	public final class CcLinkParams {
	/**
	* A list of link options contributed by a single configured target.
	*
	* <p><b>WARNING:</b> Do not implement {@code #equals()} in the obvious way. This class must be
	* checked for equality by object identity because otherwise if two configured targets contribute
	* the same link options, they will be de-duplicated, which is not the desirable behavior.
	*/
	@AutoCodec
	@Immutable
	public static final class LinkOptions {
	private final ImmutableList<String> linkOptions;

	@VisibleForSerialization
	LinkOptions(Iterable<String> linkOptions) {
	this.linkOptions = ImmutableList.copyOf(linkOptions);
	}

	public ImmutableList<String> get() {
	return linkOptions;
	}

	public static LinkOptions of(Iterable<String> linkOptions) {
	return new LinkOptions(linkOptions);
	}
	}

	private final NestedSet<LinkOptions> linkOpts;
	private final NestedSet<Linkstamp> linkstamps;
	private final NestedSet<LibraryToLink> libraries;
	private final NestedSet<Artifact> executionDynamicLibraries;
	private final ExtraLinkTimeLibraries extraLinkTimeLibraries;
	private final NestedSet<Artifact> nonCodeInputs;

	@AutoCodec.Instantiator
	@VisibleForSerialization
	CcLinkParams(
	NestedSet<LinkOptions> linkOpts,
	NestedSet<Linkstamp> linkstamps,
	NestedSet<LibraryToLink> libraries,
	NestedSet<Artifact> executionDynamicLibraries,
	ExtraLinkTimeLibraries extraLinkTimeLibraries,
	NestedSet<Artifact> nonCodeInputs) {
	this.linkOpts = linkOpts;
	this.linkstamps = linkstamps;
	this.libraries = libraries;
	this.executionDynamicLibraries = executionDynamicLibraries;
	this.extraLinkTimeLibraries = extraLinkTimeLibraries;
	this.nonCodeInputs = nonCodeInputs;
	}

	/**
	* Returns the linkopts
	*/
	public NestedSet<LinkOptions> getLinkopts() {
	return linkOpts;
	}

	public ImmutableList<String> flattenedLinkopts() {
	return ImmutableList.copyOf(Iterables.concat(Iterables.transform(linkOpts, LinkOptions::get)));
	}

	/**
	* Returns the linkstamps
	*/
	public NestedSet<Linkstamp> getLinkstamps() {
	return linkstamps;
	}

	/**
	* Returns the libraries
	*/
	public NestedSet<LibraryToLink> getLibraries() {
	return libraries;
	}

	/**
	* Returns the executionDynamicLibraries.
	*/
	public NestedSet<Artifact> getExecutionDynamicLibraries() {
	return executionDynamicLibraries;
	}

	/**
	* The extra link time libraries; will be null if there are no such libraries.
	*/
	public @Nullable ExtraLinkTimeLibraries getExtraLinkTimeLibraries() {
	return extraLinkTimeLibraries;
	}

	/**
	* Returns the non-code inputs, e.g. linker scripts; will be null if none.
	*/
	public @Nullable NestedSet<Artifact> getNonCodeInputs() {
	return nonCodeInputs;
	}

	public static final Builder builder(boolean linkingStatically, boolean linkShared) {
	return new Builder(linkingStatically, linkShared);
	}

	/**
	* Builder for {@link CcLinkParams}.
	*/
	public static final class Builder {

	/**
	* linkingStatically is true when we're linking this target in either FULLY STATIC mode
	* (linkopts=["-static"]) or MOSTLY STATIC mode (linkstatic=1). When this is true, we want to
	* use static versions of any libraries that this target depends on (except possibly system
	* libraries, which are not handled by CcLinkParams). When this is false, we want to use dynamic
	* versions of any libraries that this target depends on.
	*/
	private final boolean linkingStatically;

	/**
	* linkShared is true when we're linking with "-shared" (linkshared=1).
	*/
	private final boolean linkShared;

	private ImmutableList.Builder<String> localLinkoptsBuilder = ImmutableList.builder();

	private final NestedSetBuilder<LinkOptions> linkOptsBuilder =
	NestedSetBuilder.linkOrder();
	private final NestedSetBuilder<Linkstamp> linkstampsBuilder =
	NestedSetBuilder.compileOrder();
	private final NestedSetBuilder<LibraryToLink> librariesBuilder =
	NestedSetBuilder.linkOrder();
	private final NestedSetBuilder<Artifact> executionDynamicLibrariesBuilder =
	NestedSetBuilder.stableOrder();

	/**
	* A builder for the list of link time libraries. Most builds
	* won't have any such libraries, so save space by leaving the
	* default as null.
	*/
	private ExtraLinkTimeLibraries.Builder extraLinkTimeLibrariesBuilder = null;

	private NestedSetBuilder<Artifact> nonCodeInputsBuilder = null;

	private boolean built = false;

	private Builder(boolean linkingStatically, boolean linkShared) {
	this.linkingStatically = linkingStatically;
	this.linkShared = linkShared;
	}

	/**
	* Builds a {@link CcLinkParams} object.
	*/
	public CcLinkParams build() {
	Preconditions.checkState(!built);
	// Not thread-safe, but builders should not be shared across threads.
	built = true;
	ImmutableList<String> localLinkopts = localLinkoptsBuilder.build();
	if (!localLinkopts.isEmpty()) {
	linkOptsBuilder.add(LinkOptions.of(localLinkopts));
	}
	ExtraLinkTimeLibraries extraLinkTimeLibraries = null;
	if (extraLinkTimeLibrariesBuilder != null) {
	extraLinkTimeLibraries = extraLinkTimeLibrariesBuilder.build();
	}
	NestedSet<Artifact> nonCodeInputs = null;
	if (nonCodeInputsBuilder != null) {
	nonCodeInputs = nonCodeInputsBuilder.build();
	}
	return new CcLinkParams(
	linkOptsBuilder.build(),
	linkstampsBuilder.build(),
	librariesBuilder.build(),
	executionDynamicLibrariesBuilder.build(),
	extraLinkTimeLibraries,
	nonCodeInputs);
	}

	public boolean add(CcLinkParamsStore store) {
	if (store != null) {
	CcLinkParams args = store.get(linkingStatically, linkShared);
	addTransitiveArgs(args);
	}
	return store != null;
	}

	/**
	* Includes link parameters from a collection of dependency targets.
	*/
	public Builder addTransitiveTargets(Iterable<? extends TransitiveInfoCollection> targets) {
	for (TransitiveInfoCollection target : targets) {
	addTransitiveTarget(target);
	}
	return this;
	}

	/**
	* Includes link parameters from a dependency target.
	*
	* <p>The target should implement {@link CcLinkParamsInfo}. If it does not,
	* the method does not do anything.
	*/
	public Builder addTransitiveTarget(TransitiveInfoCollection target) {
	CcLinkingInfo ccLinkingInfo = target.get(CcLinkingInfo.PROVIDER);
	CcLinkParamsInfo ccLinkParamsInfo =
	ccLinkingInfo == null ? null : ccLinkingInfo.getCcLinkParamsInfo();
	return addTransitiveProvider(ccLinkParamsInfo);
	}

	/**
	* Includes link parameters from a dependency target. The target is checked for the given
	* mappings in the order specified, and the first mapping that returns a non-null result is
	* added.
	*/
	@SafeVarargs
	public final Builder addTransitiveTarget(TransitiveInfoCollection target,
	Function<TransitiveInfoCollection, CcLinkParamsStore> firstMapping,
	@SuppressWarnings("unchecked") // Java arrays don't preserve generic arguments.
	Function<TransitiveInfoCollection, CcLinkParamsStore>... remainingMappings) {
	if (add(firstMapping.apply(target))) {
	return this;
	}
	for (Function<TransitiveInfoCollection, CcLinkParamsStore> mapping : remainingMappings) {
	if (add(mapping.apply(target))) {
	return this;
	}
	}
	return this;
	}

	/**
	* Includes link parameters from a CcLinkParamsInfo provider.
	*/
	public Builder addTransitiveProvider(CcLinkParamsInfo provider) {
	if (provider != null) {
	add(provider.getCcLinkParamsStore());
	}
	return this;
	}

	/**
	* Includes link parameters from the given targets. Each target is checked for the given
	* mappings in the order specified, and the first mapping that returns a non-null result is
	* added.
	*/
	@SafeVarargs
	public final Builder addTransitiveTargets(
	Iterable<? extends TransitiveInfoCollection> targets,
	Function<TransitiveInfoCollection, CcLinkParamsStore> firstMapping,
	@SuppressWarnings("unchecked") // Java arrays don't preserve generic arguments.
	Function<TransitiveInfoCollection, CcLinkParamsStore>... remainingMappings) {
	for (TransitiveInfoCollection target : targets) {
	addTransitiveTarget(target, firstMapping, remainingMappings);
	}
	return this;
	}

	/**
	* Merges the other {@link CcLinkParams} object into this one.
	*/
	public Builder addTransitiveArgs(CcLinkParams args) {
	linkOptsBuilder.addTransitive(args.getLinkopts());
	linkstampsBuilder.addTransitive(args.getLinkstamps());
	librariesBuilder.addTransitive(args.getLibraries());
	executionDynamicLibrariesBuilder.addTransitive(args.getExecutionDynamicLibraries());
	if (args.getExtraLinkTimeLibraries() != null) {
	if (extraLinkTimeLibrariesBuilder == null) {
	extraLinkTimeLibrariesBuilder = ExtraLinkTimeLibraries.builder();
	}
	extraLinkTimeLibrariesBuilder.addTransitive(args.getExtraLinkTimeLibraries());
	}
	if (args.getNonCodeInputs() != null) {
	if (nonCodeInputsBuilder == null) {
	nonCodeInputsBuilder = NestedSetBuilder.linkOrder();
	}
	nonCodeInputsBuilder.addTransitive(args.getNonCodeInputs());
	}
	return this;
	}

	/**
	* Adds a collection of link options.
	*/
	public Builder addLinkOpts(Collection<String> linkOpts) {
	localLinkoptsBuilder.addAll(linkOpts);
	return this;
	}

	/** Adds a collection of linkstamps. */
	public Builder addLinkstamps(
	NestedSet<Artifact> linkstamps, CcCompilationContext ccCompilationContext) {
	for (Artifact linkstamp : linkstamps) {
	linkstampsBuilder.add(
	new Linkstamp(linkstamp, ccCompilationContext.getDeclaredIncludeSrcs()));
	}
	return this;
	}

	/**
	* Adds a library artifact.
	*/
	public Builder addLibrary(LibraryToLink library) {
	librariesBuilder.add(library);
	return this;
	}

	/**
	* Adds a collection of library artifacts.
	*/
	public Builder addLibraries(Iterable<LibraryToLink> libraries) {
	librariesBuilder.addAll(libraries);
	return this;
	}

	/** Adds a collection of library artifacts. */
	public Builder addExecutionDynamicLibraries(Iterable<Artifact> libraries) {
	executionDynamicLibrariesBuilder.addAll(libraries);
	return this;
	}

	/**
	* Adds an extra link time library, a library that is actually
	* built at link time.
	*/
	public Builder addExtraLinkTimeLibrary(ExtraLinkTimeLibrary e) {
	if (extraLinkTimeLibrariesBuilder == null) {
	extraLinkTimeLibrariesBuilder = ExtraLinkTimeLibraries.builder();
	}
	extraLinkTimeLibrariesBuilder.add(e);
	return this;
	}

	/**
	* Adds a collection of non-code inputs.
	*/
	public Builder addNonCodeInputs(Iterable<Artifact> nonCodeInputs) {
	if (nonCodeInputsBuilder == null) {
	nonCodeInputsBuilder = NestedSetBuilder.linkOrder();
	}
	nonCodeInputsBuilder.addAll(nonCodeInputs);
	return this;
	}

	/** Processes typical dependencies of a C/C++ library. */
	public Builder addCcLibrary(RuleContext context) {
	addTransitiveTargets(
	context.getPrerequisites("deps", Mode.TARGET),
	CcLinkParamsInfo.TO_LINK_PARAMS,
	CcSpecificLinkParamsProvider.TO_LINK_PARAMS);
	return this;
	}
	}

	/**
	* A linkstamp that also knows about its declared includes.
	*
	* <p>This object is required because linkstamp files may include other headers which will have to
	* be provided during compilation.
	*/
	@AutoCodec
	public static final class Linkstamp {
	private final Artifact artifact;
	private final NestedSet<Artifact> declaredIncludeSrcs;

	@VisibleForSerialization
	Linkstamp(Artifact artifact, NestedSet<Artifact> declaredIncludeSrcs) {
	this.artifact = Preconditions.checkNotNull(artifact);
	this.declaredIncludeSrcs = Preconditions.checkNotNull(declaredIncludeSrcs);
	}

	/**
	* Returns the linkstamp artifact.
	*/
	public Artifact getArtifact() {
	return artifact;
	}

	/**
	* Returns the declared includes.
	*/
	public NestedSet<Artifact> getDeclaredIncludeSrcs() {
	return declaredIncludeSrcs;
	}

	@Override
	public int hashCode() {
	return Objects.hash(artifact, declaredIncludeSrcs);
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (!(obj instanceof Linkstamp)) {
	return false;
	}
	Linkstamp other = (Linkstamp) obj;
	return artifact.equals(other.artifact)
	&& declaredIncludeSrcs.equals(other.declaredIncludeSrcs);
	}
	}

	/** Empty CcLinkParams. */
	public static final CcLinkParams EMPTY =
	new CcLinkParams(
	NestedSetBuilder.<LinkOptions>emptySet(Order.LINK_ORDER),
	NestedSetBuilder.<Linkstamp>emptySet(Order.COMPILE_ORDER),
	NestedSetBuilder.<LibraryToLink>emptySet(Order.LINK_ORDER),
	NestedSetBuilder.<Artifact>emptySet(Order.STABLE_ORDER),
	null,
	null);
	}