| // 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 com.google.common.base.Preconditions; |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.analysis.PlatformOptions; |
| 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.cmdline.Label; |
| import com.google.devtools.build.lib.packages.AttributeTransitionData; |
| 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. |
| */ |
| public class ExecutionTransitionFactory implements TransitionFactory<AttributeTransitionData> { |
| |
| private ExecutionTransitionFactory() {} |
| |
| /** Returns a new {@link ExecutionTransitionFactory}. */ |
| public static ExecutionTransitionFactory create() { |
| return new ExecutionTransitionFactory(); |
| } |
| |
| /** |
| * Returns either a new {@link ExecutionTransitionFactory} or a factory for the {@link |
| * HostTransition}, depending on the value of {@code enableExecutionTransition}. |
| */ |
| public static TransitionFactory<AttributeTransitionData> create( |
| boolean enableExecutionTransition) { |
| if (enableExecutionTransition) { |
| return create(); |
| } else { |
| return HostTransition.createFactory(); |
| } |
| } |
| |
| @Override |
| public PatchTransition create(AttributeTransitionData data) { |
| return new ExecutionTransition(data.executionPlatform()); |
| } |
| |
| @Override |
| public boolean isHost() { |
| return false; |
| } |
| |
| @Override |
| public boolean isTool() { |
| return true; |
| } |
| |
| private static class ExecutionTransition implements PatchTransition { |
| @Nullable private final Label executionPlatform; |
| |
| public ExecutionTransition(@Nullable Label executionPlatform) { |
| this.executionPlatform = executionPlatform; |
| } |
| |
| @Override |
| public String getName() { |
| return "exec"; |
| } |
| |
| @Override |
| public boolean isHostTransition() { |
| return false; |
| } |
| |
| // We added this cache after observing an O(100,000)-node build graph that applied multiple exec |
| // transitions on every node via an aspect. Before this cache, this produced O(500,000) |
| // BuildOptions instances that consumed over 3 gigabytes of memory. |
| private static final BuildOptionsCache<Label> cache = new BuildOptionsCache<>(); |
| |
| @Override |
| public BuildOptions patch(BuildOptions options) { |
| if (executionPlatform == null) { |
| // No execution platform is known, so don't change anything. |
| return options; |
| } |
| return cache.applyTransition( |
| options, |
| // The execution platform impacts the output's --platform_suffix and --platforms flags. |
| executionPlatform, |
| () -> { |
| // Start by converting to host options. |
| BuildOptions execConfiguration = options.createHostOptions(); |
| |
| // Then unset isHost, if CoreOptions is available. |
| CoreOptions coreOptions = |
| Preconditions.checkNotNull(execConfiguration.get(CoreOptions.class)); |
| coreOptions.isHost = false; |
| coreOptions.isExec = true; |
| coreOptions.outputDirectoryName = null; |
| coreOptions.platformSuffix = |
| String.format("-exec-%X", executionPlatform.getCanonicalForm().hashCode()); |
| |
| // Then set the target to the saved execution platform if there is one. |
| if (execConfiguration.get(PlatformOptions.class) != null) { |
| execConfiguration.get(PlatformOptions.class).platforms = |
| ImmutableList.of(executionPlatform); |
| } |
| |
| return execConfiguration; |
| }); |
| } |
| } |
| } |