src/main/java/com/google/devtools/build/lib/analysis/config/ExecutionTransitionFactory.java - bazel - Git at Google

 // Copyright 2019 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.analysis.config;

 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.devtools.build.lib.packages.ExecGroup.DEFAULT_EXEC_GROUP_NAME;

 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.google.common.base.Verify;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.analysis.PlatformOptions;
 import com.google.devtools.build.lib.analysis.config.transitions.ConfigurationTransition;
 import com.google.devtools.build.lib.analysis.config.transitions.PatchTransition;
 import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 import com.google.devtools.build.lib.analysis.starlark.FunctionTransitionUtil;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.packages.AttributeTransitionData;
 import com.google.devtools.build.lib.rules.config.FeatureFlagValue;
 import com.google.devtools.build.lib.starlarkbuildapi.config.StarlarkConfigApi.ExecTransitionFactoryApi;
 import com.google.devtools.build.lib.util.Pair;
 import java.util.Map;
 import javax.annotation.Nullable;

 /**
  * {@link TransitionFactory} implementation which creates a {@link PatchTransition} which will
  * transition to a configuration suitable for building dependencies for the execution platform of
  * the depending target.
  *
  * <p>Note that execGroup is not directly consumed by the involved transition but instead stored
  * here. Instead, the rule definition stores it in this factory. Then, toolchain resolution extracts
  * and consumes it to store an execution platform in attrs. Finally, the execution platform is read
  * by the factory to create the transition.
  */
 public class ExecutionTransitionFactory
     implements TransitionFactory<AttributeTransitionData>, ExecTransitionFactoryApi {

   /**
    * Returns a new {@link ExecutionTransitionFactory} for the default {@link
    * com.google.devtools.build.lib.packages.ExecGroup}.
    */
   public static ExecutionTransitionFactory createFactory() {
     return new ExecutionTransitionFactory(DEFAULT_EXEC_GROUP_NAME);
   }

   /**
    * Returns a new {@link ExecutionTransitionFactory} for the given {@link
    * com.google.devtools.build.lib.packages.ExecGroup}.
    */
   public static ExecutionTransitionFactory createFactory(String execGroup) {
     return new ExecutionTransitionFactory(execGroup);
   }

   /**
    * Guarantees we don't duplicate instances of the same transition.
    *
    * <p>Bazel's Starlark logic also maintains a distinct instance for each Starlark transition.
    * While that makes this cache seem unnecessary, it still has value. The exec transition uniquely
    * takes an extra parameter: the execution platform label. This is provided by toolchain
    * resolution - the transition can't read it from input build options. So we need to cache on
    * {@code label, originalTransition} pairs.
    */
   private static final Cache<Pair<Label, Integer>, PatchTransition> transitionInstanceCache =
       Caffeine.newBuilder().weakValues().build();

   @Override
   public PatchTransition create(AttributeTransitionData dataWithTargetAttributes) {
     // Delete AttributeTransitionData.attributes() so the exec transition doesn't try to read the
     // attributes of the target it's attached to. This is for two reasons:
     //
     //   1) While per-target exec transitions may be interesting, we're not ready to expose that
     //      level of API flexibility
     //   2) No need for StarlarkTransitionCache misses due to different StarlarkTransition instances
     //       bound to different attributes that shouldn't affect output.
     AttributeTransitionData data =
         AttributeTransitionData.builder()
             .analysisData(dataWithTargetAttributes.analysisData())
             .executionPlatform(dataWithTargetAttributes.executionPlatform())
             .build();

     @SuppressWarnings("unchecked")
     TransitionFactory<AttributeTransitionData> starlarkExecTransitionProvider =
         (TransitionFactory<AttributeTransitionData>)
             Verify.verifyNotNull(
                 data.analysisData(), "expected a Starlark exec transition definition");

     return transitionInstanceCache.get(
         // A Starlark transition keeps the same instance unless we modify its .bzl file.
         Pair.of(data.executionPlatform(), starlarkExecTransitionProvider.hashCode()),
         (p) ->
             new ExecTransitionFinalizer(
                 data.executionPlatform(), starlarkExecTransitionProvider.create(data)));
   }

   private final String execGroup;

   private ExecutionTransitionFactory(String execGroup) {
     this.execGroup = execGroup;
   }

   @Override
   public TransitionType transitionType() {
     return TransitionType.ATTRIBUTE;
   }

   public String getExecGroup() {
     return execGroup;
   }

   @Override
   public boolean isTool() {
     return true;
   }

   /**
    * Complete exec transition.
    *
    * <p>Takes as input the execution platform and the main transition. Calls the main transition,
    * then runs finalizer logic that has to be handled natively.
    */
   private static class ExecTransitionFinalizer implements PatchTransition {
     private static final ImmutableSet<Class<? extends FragmentOptions>> FRAGMENTS =
         ImmutableSet.of(CoreOptions.class, PlatformOptions.class);

     @Nullable private final Label executionPlatform;

     private final ConfigurationTransition mainTransition;

     ExecTransitionFinalizer(
         @Nullable Label executionPlatform, ConfigurationTransition mainTransition) {
       this.executionPlatform = executionPlatform;
       this.mainTransition = mainTransition;
     }

     @Override
     public String getName() {
       return "exec";
     }

     /**
      * Implement {@link ConfigurationTransition#visit}} so {@link
      * com.google.devtools.build.lib.analysis.config.StarlarkTransitionCache} caches application if
      * this is a Starlark transition.
      */
     @Override
     public <E extends Exception> void visit(Visitor<E> visitor) throws E {
       this.mainTransition.visit(visitor);
     }

     @Override
     public ImmutableSet<Class<? extends FragmentOptions>> requiresOptionFragments() {
       // This is technically a lie since the call to underlying().createExecOptions is transitively
       // reading and potentially modifying all fragments. There is currently no way for the
       // transition to actually list all fragments like this and thus only lists the ones that are
       // directly being read here. Note that this transition is exceptional in its implementation.
       return FRAGMENTS;
     }

     @Override
     public BuildOptions patch(BuildOptionsView options, EventHandler eventHandler)
         throws InterruptedException {
       if (executionPlatform == null) {
         // No execution platform is known, so don't change anything.
         return options.underlying();
       }

       Map.Entry<String, BuildOptions> splitOptions =
           Iterables.getOnlyElement(mainTransition.apply(options, eventHandler).entrySet());
       BuildOptions execOptions = splitOptions.getValue();

       // Set the target to the saved execution platform if there is one.
       PlatformOptions platformOptions = execOptions.get(PlatformOptions.class);
       if (platformOptions != null) {
         platformOptions.platforms = ImmutableList.of(executionPlatform);
       }

       // Remove any FeatureFlags that were set.
       ImmutableList<Label> featureFlags =
           execOptions.getStarlarkOptions().entrySet().stream()
               .filter(entry -> entry.getValue() instanceof FeatureFlagValue)
               .map(Map.Entry::getKey)
               .collect(toImmutableList());

       BuildOptions result = execOptions;
       if (!featureFlags.isEmpty()) {
         BuildOptions.Builder resultBuilder = result.toBuilder();
         featureFlags.forEach(resultBuilder::removeStarlarkOption);
         result = resultBuilder.build();
       }

       // The conditional use of a Builder above may have replaced result and underlying options
       // with a clone so must refresh it.
       CoreOptions coreOptions = result.get(CoreOptions.class);
       // TODO(blaze-configurability-team): These updates probably requires a bit too much knowledge
       //   of exactly how the immutable state and mutable state of BuildOptions is interacting.
       //   Might be good to have an option to wipeout that state rather than cloning so much.
       switch (coreOptions.execConfigurationDistinguisherScheme) {
         case LEGACY:
           coreOptions.platformSuffix =
               String.format("exec-%X", executionPlatform.getCanonicalForm().hashCode());
           break;
         case FULL_HASH:
           coreOptions.platformSuffix = "";
           // execOptions creation above made a clone, which will have a fresh hashCode
           int fullHash = result.hashCode();
           coreOptions.platformSuffix = String.format("exec-%X", fullHash);
           // Previous call to hashCode irreparably locked in state so must clone to refresh since
           // options mutated after that
           result = result.clone();
           break;
         case DIFF_TO_AFFECTED:
           // Setting platform_suffix here should not be necessary for correctness but
           // done for user clarity.
           coreOptions.platformSuffix = "exec";
           ImmutableSet<String> diff =
               FunctionTransitionUtil.getAffectedByStarlarkTransitionViaDiff(
                   result, options.underlying());
           FunctionTransitionUtil.updateAffectedByStarlarkTransition(coreOptions, diff);
           // Previous call to diff irreparably locked in state so must clone to refresh.
           result = result.clone();
           break;
         default:
           // else if OFF just mark that we are now in an exec transition
           coreOptions.platformSuffix = "exec";
       }
       coreOptions.affectedByStarlarkTransition =
           options.underlying().get(CoreOptions.class).affectedByStarlarkTransition;
       coreOptions.executionInfoModifier =
           options.underlying().get(CoreOptions.class).executionInfoModifier;
       coreOptions.overrideNamePlatformInOutputDirEntries =
           options.underlying().get(CoreOptions.class).overrideNamePlatformInOutputDirEntries;
       return result;
     }
   }
 }
	// Copyright 2019 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.analysis.config;

	import static com.google.common.collect.ImmutableList.toImmutableList;
	import static com.google.devtools.build.lib.packages.ExecGroup.DEFAULT_EXEC_GROUP_NAME;

	import com.github.benmanes.caffeine.cache.Cache;
	import com.github.benmanes.caffeine.cache.Caffeine;
	import com.google.common.base.Verify;
	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.ImmutableSet;
	import com.google.common.collect.Iterables;
	import com.google.devtools.build.lib.analysis.PlatformOptions;
	import com.google.devtools.build.lib.analysis.config.transitions.ConfigurationTransition;
	import com.google.devtools.build.lib.analysis.config.transitions.PatchTransition;
	import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
	import com.google.devtools.build.lib.analysis.starlark.FunctionTransitionUtil;
	import com.google.devtools.build.lib.cmdline.Label;
	import com.google.devtools.build.lib.events.EventHandler;
	import com.google.devtools.build.lib.packages.AttributeTransitionData;
	import com.google.devtools.build.lib.rules.config.FeatureFlagValue;
	import com.google.devtools.build.lib.starlarkbuildapi.config.StarlarkConfigApi.ExecTransitionFactoryApi;
	import com.google.devtools.build.lib.util.Pair;
	import java.util.Map;
	import javax.annotation.Nullable;

	/**
	* {@link TransitionFactory} implementation which creates a {@link PatchTransition} which will
	* transition to a configuration suitable for building dependencies for the execution platform of
	* the depending target.
	*
	* <p>Note that execGroup is not directly consumed by the involved transition but instead stored
	* here. Instead, the rule definition stores it in this factory. Then, toolchain resolution extracts
	* and consumes it to store an execution platform in attrs. Finally, the execution platform is read
	* by the factory to create the transition.
	*/
	public class ExecutionTransitionFactory
	implements TransitionFactory<AttributeTransitionData>, ExecTransitionFactoryApi {

	/**
	* Returns a new {@link ExecutionTransitionFactory} for the default {@link
	* com.google.devtools.build.lib.packages.ExecGroup}.
	*/
	public static ExecutionTransitionFactory createFactory() {
	return new ExecutionTransitionFactory(DEFAULT_EXEC_GROUP_NAME);
	}

	/**
	* Returns a new {@link ExecutionTransitionFactory} for the given {@link
	* com.google.devtools.build.lib.packages.ExecGroup}.
	*/
	public static ExecutionTransitionFactory createFactory(String execGroup) {
	return new ExecutionTransitionFactory(execGroup);
	}

	/**
	* Guarantees we don't duplicate instances of the same transition.
	*
	* <p>Bazel's Starlark logic also maintains a distinct instance for each Starlark transition.
	* While that makes this cache seem unnecessary, it still has value. The exec transition uniquely
	* takes an extra parameter: the execution platform label. This is provided by toolchain
	* resolution - the transition can't read it from input build options. So we need to cache on
	* {@code label, originalTransition} pairs.
	*/
	private static final Cache<Pair<Label, Integer>, PatchTransition> transitionInstanceCache =
	Caffeine.newBuilder().weakValues().build();

	@Override
	public PatchTransition create(AttributeTransitionData dataWithTargetAttributes) {
	// Delete AttributeTransitionData.attributes() so the exec transition doesn't try to read the
	// attributes of the target it's attached to. This is for two reasons:
	//
	// 1) While per-target exec transitions may be interesting, we're not ready to expose that
	// level of API flexibility
	// 2) No need for StarlarkTransitionCache misses due to different StarlarkTransition instances
	// bound to different attributes that shouldn't affect output.
	AttributeTransitionData data =
	AttributeTransitionData.builder()
	.analysisData(dataWithTargetAttributes.analysisData())
	.executionPlatform(dataWithTargetAttributes.executionPlatform())
	.build();

	@SuppressWarnings("unchecked")
	TransitionFactory<AttributeTransitionData> starlarkExecTransitionProvider =
	(TransitionFactory<AttributeTransitionData>)
	Verify.verifyNotNull(
	data.analysisData(), "expected a Starlark exec transition definition");

	return transitionInstanceCache.get(
	// A Starlark transition keeps the same instance unless we modify its .bzl file.
	Pair.of(data.executionPlatform(), starlarkExecTransitionProvider.hashCode()),
	(p) ->
	new ExecTransitionFinalizer(
	data.executionPlatform(), starlarkExecTransitionProvider.create(data)));
	}

	private final String execGroup;

	private ExecutionTransitionFactory(String execGroup) {
	this.execGroup = execGroup;
	}

	@Override
	public TransitionType transitionType() {
	return TransitionType.ATTRIBUTE;
	}

	public String getExecGroup() {
	return execGroup;
	}

	@Override
	public boolean isTool() {
	return true;
	}

	/**
	* Complete exec transition.
	*
	* <p>Takes as input the execution platform and the main transition. Calls the main transition,
	* then runs finalizer logic that has to be handled natively.
	*/
	private static class ExecTransitionFinalizer implements PatchTransition {
	private static final ImmutableSet<Class<? extends FragmentOptions>> FRAGMENTS =
	ImmutableSet.of(CoreOptions.class, PlatformOptions.class);

	@Nullable private final Label executionPlatform;

	private final ConfigurationTransition mainTransition;

	ExecTransitionFinalizer(
	@Nullable Label executionPlatform, ConfigurationTransition mainTransition) {
	this.executionPlatform = executionPlatform;
	this.mainTransition = mainTransition;
	}

	@Override
	public String getName() {
	return "exec";
	}

	/**
	* Implement {@link ConfigurationTransition#visit}} so {@link
	* com.google.devtools.build.lib.analysis.config.StarlarkTransitionCache} caches application if
	* this is a Starlark transition.
	*/
	@Override
	public <E extends Exception> void visit(Visitor<E> visitor) throws E {
	this.mainTransition.visit(visitor);
	}

	@Override
	public ImmutableSet<Class<? extends FragmentOptions>> requiresOptionFragments() {
	// This is technically a lie since the call to underlying().createExecOptions is transitively
	// reading and potentially modifying all fragments. There is currently no way for the
	// transition to actually list all fragments like this and thus only lists the ones that are
	// directly being read here. Note that this transition is exceptional in its implementation.
	return FRAGMENTS;
	}

	@Override
	public BuildOptions patch(BuildOptionsView options, EventHandler eventHandler)
	throws InterruptedException {
	if (executionPlatform == null) {
	// No execution platform is known, so don't change anything.
	return options.underlying();
	}

	Map.Entry<String, BuildOptions> splitOptions =
	Iterables.getOnlyElement(mainTransition.apply(options, eventHandler).entrySet());
	BuildOptions execOptions = splitOptions.getValue();

	// Set the target to the saved execution platform if there is one.
	PlatformOptions platformOptions = execOptions.get(PlatformOptions.class);
	if (platformOptions != null) {
	platformOptions.platforms = ImmutableList.of(executionPlatform);
	}

	// Remove any FeatureFlags that were set.
	ImmutableList<Label> featureFlags =
	execOptions.getStarlarkOptions().entrySet().stream()
	.filter(entry -> entry.getValue() instanceof FeatureFlagValue)
	.map(Map.Entry::getKey)
	.collect(toImmutableList());

	BuildOptions result = execOptions;
	if (!featureFlags.isEmpty()) {
	BuildOptions.Builder resultBuilder = result.toBuilder();
	featureFlags.forEach(resultBuilder::removeStarlarkOption);
	result = resultBuilder.build();
	}

	// The conditional use of a Builder above may have replaced result and underlying options
	// with a clone so must refresh it.
	CoreOptions coreOptions = result.get(CoreOptions.class);
	// TODO(blaze-configurability-team): These updates probably requires a bit too much knowledge
	// of exactly how the immutable state and mutable state of BuildOptions is interacting.
	// Might be good to have an option to wipeout that state rather than cloning so much.
	switch (coreOptions.execConfigurationDistinguisherScheme) {
	case LEGACY:
	coreOptions.platformSuffix =
	String.format("exec-%X", executionPlatform.getCanonicalForm().hashCode());
	break;
	case FULL_HASH:
	coreOptions.platformSuffix = "";
	// execOptions creation above made a clone, which will have a fresh hashCode
	int fullHash = result.hashCode();
	coreOptions.platformSuffix = String.format("exec-%X", fullHash);
	// Previous call to hashCode irreparably locked in state so must clone to refresh since
	// options mutated after that
	result = result.clone();
	break;
	case DIFF_TO_AFFECTED:
	// Setting platform_suffix here should not be necessary for correctness but
	// done for user clarity.
	coreOptions.platformSuffix = "exec";
	ImmutableSet<String> diff =
	FunctionTransitionUtil.getAffectedByStarlarkTransitionViaDiff(
	result, options.underlying());
	FunctionTransitionUtil.updateAffectedByStarlarkTransition(coreOptions, diff);
	// Previous call to diff irreparably locked in state so must clone to refresh.
	result = result.clone();
	break;
	default:
	// else if OFF just mark that we are now in an exec transition
	coreOptions.platformSuffix = "exec";
	}
	coreOptions.affectedByStarlarkTransition =
	options.underlying().get(CoreOptions.class).affectedByStarlarkTransition;
	coreOptions.executionInfoModifier =
	options.underlying().get(CoreOptions.class).executionInfoModifier;
	coreOptions.overrideNamePlatformInOutputDirEntries =
	options.underlying().get(CoreOptions.class).overrideNamePlatformInOutputDirEntries;
	return result;
	}
	}
	}