Add basic incompatible target skipping

This patch aims to implement a basic version of incompatible target
skipping outlined here:
https://docs.google.com/document/d/12n5QNHmFSkuh5yAbdEex64ot4hRgR-moL1zRimU7wHQ/edit?usp=sharing

The implementation in this patch supports only "top level" target
skipping. In other words we only filter out targets if they are
globbed as part of an invocation like "bazel build //...".

The following features are not yet implemented:
- Filtering targets based on transitive dependencies. For example, if
  //a:b depends on //c:d an invocation of "bazel build //a/..." will
  still build //c:d even if it is incompatible with the current
  platform.
- Being able to select() on constraint values. For example, it's not
  possible to select() based on whether or not GCC is being used.
  Discussion of this aspect of the proposal is ongoing:
  https://groups.google.com/d/msg/bazel-dev/xK7diubpljQ/s3KSRwTWAQAJ

The goal is to implement the missing features in follow-up patches.

src/main/java/com/google/devtools/build/lib/analysis/BUILD

@@ -326,6 +326,7 @@ java_library(
         ":extra/extra_action_info_file_write_action",
         ":extra_action_artifacts_provider",
         ":file_provider",
+        ":incompatible_platform_provider",
         ":inconsistent_aspect_order_exception",
         ":label_and_location",
         ":label_expander",
@@ -373,6 +374,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/actions:execution_requirements",
         "//src/main/java/com/google/devtools/build/lib/actions:localhost_capacity",
         "//src/main/java/com/google/devtools/build/lib/analysis/platform",
+        "//src/main/java/com/google/devtools/build/lib/analysis/platform:utils",
         "//src/main/java/com/google/devtools/build/lib/analysis/stringtemplate",
         "//src/main/java/com/google/devtools/build/lib/bugreport",
         "//src/main/java/com/google/devtools/build/lib/buildeventstream",
@@ -598,6 +600,7 @@ java_library(
         ":configured_target",
         ":constraints/top_level_constraint_semantics",
         ":extra_action_artifacts_provider",
+        ":incompatible_platform_provider",
         ":make_environment_event",
         ":target_configured_event",
         ":test/coverage_report_action_factory",
@@ -767,6 +770,15 @@ java_library(
     ],
 )
 
+java_library(
+    name = "incompatible_platform_provider",
+    srcs = ["IncompatiblePlatformProvider.java"],
+    deps = [
+        ":transitive_info_provider",
+        "//src/main/java/com/google/devtools/build/lib/concurrent",
+    ],
+)
+
 java_library(
     name = "inconsistent_aspect_order_exception",
     srcs = ["InconsistentAspectOrderException.java"],

src/main/java/com/google/devtools/build/lib/analysis/BaseRuleClasses.java

@@ -34,6 +34,7 @@
 import com.google.devtools.build.lib.analysis.config.HostTransition;
 import com.google.devtools.build.lib.analysis.config.RunUnder;
 import com.google.devtools.build.lib.analysis.constraints.ConstraintConstants;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
 import com.google.devtools.build.lib.analysis.test.TestConfiguration;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.packages.Attribute;
@@ -327,6 +328,15 @@ public static RuleClass.Builder commonCoreAndStarlarkAttributes(RuleClass.Builde
                 .dontCheckConstraints()
                 .nonconfigurable(
                     "special logic for constraints and select: see ConstraintSemantics"))
+        /* <!-- #BLAZE_RULE(toolchain).ATTRIBUTE(target_compatible_with) -->
+        A list of <code>constraint_value</code>s that must be satisfied by the target platform in
+        order for this toolchain to be selected for a target building for that platform.
+        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
+        .add(
+            attr("target_compatible_with", LABEL_LIST)
+                .mandatoryProviders(ConstraintValueInfo.PROVIDER.id())
+                .allowedFileTypes()
+                .nonconfigurable("Logic for target compatibility"))
         .add(
             attr(RuleClass.CONFIG_SETTING_DEPS_ATTRIBUTE, LABEL_LIST)
                 .nonconfigurable("stores configurability keys"))

src/main/java/com/google/devtools/build/lib/analysis/BuildView.java

@@ -41,7 +41,6 @@
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
 import com.google.devtools.build.lib.analysis.config.ConfigurationResolver.TopLevelTargetsAndConfigsResult;
 import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
-import com.google.devtools.build.lib.analysis.constraints.TopLevelConstraintSemantics;
 import com.google.devtools.build.lib.analysis.test.CoverageReportActionFactory;
 import com.google.devtools.build.lib.analysis.test.CoverageReportActionFactory.CoverageReportActionsWrapper;
 import com.google.devtools.build.lib.analysis.test.InstrumentedFilesInfo;
@@ -211,6 +210,7 @@ public AnalysisResult update(
       TargetPatternPhaseValue loadingResult,
       BuildOptions targetOptions,
       Set<String> multiCpu,
+      List<String> requestedTargetPatterns,
       List<String> aspects,
       AnalysisOptions viewOptions,
       boolean keepGoing,
@@ -419,6 +419,40 @@ public AnalysisResult update(
       skyframeBuildView.clearInvalidatedConfiguredTargets();
     }
 
+    ImmutableSet.Builder<ConfiguredTarget> incompatibleTargets = ImmutableSet.builder();
+    ImmutableSet.Builder<ConfiguredTarget> incompatibleButRequestedTargets = ImmutableSet.builder();
+
+    for (ConfiguredTarget target : skyframeAnalysisResult.getConfiguredTargets()) {
+      if (target.getProvider(IncompatiblePlatformProvider.class) != null) {
+        String labelString = target.getLabel().toString();
+        if (requestedTargetPatterns.contains(labelString)) {
+          if (!keepGoing) {
+            throw new ViewCreationFailedException(
+                "Target "
+                    + labelString
+                    + " is incompatible and cannot be built, but was explicitly requested.");
+          }
+          eventHandler.handle(
+              Event.warn(
+                  "Incompatible target "
+                      + labelString
+                      + " specifically requested: it will not be built"));
+          incompatibleButRequestedTargets.add(target);
+        } else {
+          incompatibleTargets.add(target);
+        }
+      }
+    }
+
+    Set<ConfiguredTarget> targetsToSkip = ImmutableSet.copyOf(incompatibleTargets.build());
+    Set<ConfiguredTarget> targetsToFail =
+        ImmutableSet.copyOf(incompatibleButRequestedTargets.build());
+
+    if (targetsToFail.size() > 0) {
+      skyframeAnalysisResult =
+          skyframeAnalysisResult.withAdditionalErroredTargets(ImmutableSet.copyOf(targetsToFail));
+    }
+
     int numTargetsToAnalyze = topLevelTargetsWithConfigs.size();
     int numSuccessful = skyframeAnalysisResult.getConfiguredTargets().size();
     if (0 < numSuccessful && numSuccessful < numTargetsToAnalyze) {
@@ -428,13 +462,6 @@ public AnalysisResult update(
       logger.atInfo().log(msg);
     }
 
-    Set<ConfiguredTarget> targetsToSkip =
-        new TopLevelConstraintSemantics(
-                skyframeExecutor.getPackageManager(),
-                input -> skyframeExecutor.getConfiguration(eventHandler, input),
-                eventHandler)
-            .checkTargetEnvironmentRestrictions(skyframeAnalysisResult.getConfiguredTargets());
-
     AnalysisResult result =
         createResult(
             eventHandler,

src/main/java/com/google/devtools/build/lib/analysis/ConfiguredTargetFactory.java

@@ -26,6 +26,7 @@
 import com.google.devtools.build.lib.actions.FailAction;
 import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
 import com.google.devtools.build.lib.analysis.RuleContext.InvalidExecGroupException;
+import com.google.devtools.build.lib.analysis.actions.SymlinkAction;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.config.ConfigMatchingProvider;
 import com.google.devtools.build.lib.analysis.config.Fragment;
@@ -35,6 +36,8 @@
 import com.google.devtools.build.lib.analysis.configuredtargets.OutputFileConfiguredTarget;
 import com.google.devtools.build.lib.analysis.configuredtargets.PackageGroupConfiguredTarget;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
+import com.google.devtools.build.lib.analysis.platform.PlatformProviderUtils;
 import com.google.devtools.build.lib.analysis.starlark.StarlarkRuleConfiguredTargetUtil;
 import com.google.devtools.build.lib.analysis.test.AnalysisFailure;
 import com.google.devtools.build.lib.analysis.test.AnalysisFailureInfo;
@@ -69,6 +72,7 @@
 import com.google.devtools.build.lib.skyframe.ConfiguredTargetAndData;
 import com.google.devtools.build.lib.skyframe.ConfiguredTargetKey;
 import com.google.devtools.build.lib.util.OrderedSetMultimap;
+import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -304,6 +308,76 @@ private ConfiguredTarget createRule(
                     prerequisiteMap.values()))
             .build();
 
+    if (!"toolchain".equals(rule.getRuleClass())) {
+      boolean isIncompatible = false;
+
+      // This is incompatible if one of the dependencies is as well.
+      for (ConfiguredTargetAndData infoCollection : prerequisiteMap.values()) {
+        if (infoCollection.getConfiguredTarget().getProvider(IncompatiblePlatformProvider.class) != null) {
+          isIncompatible = true;
+        }
+      }
+
+      // This is incompatible if explicitly specified to be.
+      if (!isIncompatible && ruleContext.attributes().has("target_compatible_with")) {
+        Iterable<ConstraintValueInfo> constraintValues =
+            PlatformProviderUtils.constraintValues(
+                ruleContext.getPrerequisites("target_compatible_with", TransitionMode.DONT_CHECK));
+        for (ConstraintValueInfo constraintValue : constraintValues) {
+          if (!ruleContext.targetPlatformHasConstraint(constraintValue)) {
+            isIncompatible = true;
+          }
+        }
+      }
+      if (isIncompatible) {
+        NestedSetBuilder<Artifact> filesToBuildBuilder =
+            NestedSetBuilder.<Artifact>stableOrder();
+
+        ImmutableList<Artifact> outputArtifacts = ruleContext.getOutputArtifacts();
+
+        if (ruleContext.isTestTarget() && outputArtifacts.size() == 0) {
+          // TODO(philsc): Figure out how to avoid this. Right now test targets require the
+          // RunfilesSupport to be added to the RuleConfiguredTargetBuilder. Can we use an input for
+          // this? How do I get access to inputs?
+          outputArtifacts = ImmutableList.of(ruleContext.createOutputArtifact());
+        }
+
+        for (Artifact output : outputArtifacts) {
+          ruleContext.registerAction(
+              SymlinkAction.toAbsolutePath(
+                  ruleContext.getActionOwner(),
+                  PathFragment.create("/bin/false"),
+                  output,
+                  "Faking out " + ruleContext.getLabel()));
+          filesToBuildBuilder.add(output);
+        }
+
+        NestedSet<Artifact> filesToBuild = filesToBuildBuilder.build();
+
+        Runfiles.Builder runfilesBuilder =
+            new Runfiles.Builder(
+                ruleContext.getWorkspaceName(),
+                ruleContext.getConfiguration().legacyExternalRunfiles());
+        Runfiles runfiles =
+            runfilesBuilder
+                .addTransitiveArtifacts(filesToBuild)
+                .addRunfiles(ruleContext, RunfilesProvider.DEFAULT_RUNFILES)
+                .build();
+
+        RuleConfiguredTargetBuilder builder = new RuleConfiguredTargetBuilder(ruleContext);
+        builder.setFilesToBuild(filesToBuild);
+        builder.add(IncompatiblePlatformProvider.class, IncompatiblePlatformProvider.simple());
+        builder.add(RunfilesProvider.class, RunfilesProvider.simple(runfiles));
+        if (outputArtifacts.size() > 0) {
+          Artifact executable = outputArtifacts.get(0);
+          RunfilesSupport runfilesSupport =
+              RunfilesSupport.withExecutable(ruleContext, runfiles, executable);
+          builder.setRunfilesSupport(runfilesSupport, executable);
+        }
+        return builder.build();
+      }
+    }
+
     List<NestedSet<AnalysisFailure>> analysisFailures = depAnalysisFailures(ruleContext);
     if (!analysisFailures.isEmpty()) {
       return erroredConfiguredTargetWithFailures(ruleContext, analysisFailures);

src/main/java/com/google/devtools/build/lib/analysis/IncompatiblePlatformProvider.java

@@ -0,0 +1,28 @@
+// Copyright 2020 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;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+
+@Immutable
+public final class IncompatiblePlatformProvider implements TransitiveInfoProvider {
+  IncompatiblePlatformProvider() {
+    // Nothing to do.
+  }
+
+  public static IncompatiblePlatformProvider simple() {
+    return new IncompatiblePlatformProvider();
+  }
+}

src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/OutputFileConfiguredTarget.java

@@ -35,6 +35,7 @@
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.Instantiator;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.VisibleForSerialization;
 import com.google.devtools.build.lib.syntax.Printer;
+import javax.annotation.Nullable;
 
 /** A ConfiguredTarget for an OutputFile. */
 @AutoCodec
@@ -114,6 +115,14 @@ public boolean hasOutputLicenses() {
         .hasOutputLicenses();
   }
 
+  @Nullable
+  @Override
+  public <P extends TransitiveInfoProvider> P getProvider(Class<P> providerClass) {
+    // TODO(bazel-team): Should aspects be allowed to override providers on the configured target
+    // class?
+    return getProvider(providerClass, null);
+  }
+
   /**
    * Returns the corresponding provider from the generating rule, if it is non-null, or {@code
    * defaultValue} otherwise.

src/main/java/com/google/devtools/build/lib/buildeventstream/proto/build_event_stream.proto

@@ -543,6 +543,7 @@ enum TestStatus {
   REMOTE_FAILURE = 6;
   FAILED_TO_BUILD = 7;
   TOOL_HALTED_BEFORE_TESTING = 8;
+  SKIPPED = 9;
 }
 
 // Payload on events reporting about individual test action.

src/main/java/com/google/devtools/build/lib/buildtool/AnalysisPhaseRunner.java

@@ -213,6 +213,7 @@ private static AnalysisResult runAnalysisPhase(
             loadingResult,
             targetOptions,
             multiCpu,
+            request.getTargets(),
             request.getAspects(),
             request.getViewOptions(),
             request.getKeepGoing(),

src/main/java/com/google/devtools/build/lib/buildtool/BuildResultPrinter.java

@@ -86,16 +86,22 @@ void showBuildResult(
       if (targetsToPrint.size() > request.getBuildOptions().maxResultTargets) {
         return;
       }
-      // Filter the targets we care about into two buckets:
+      // Filter the targets we care about into three buckets:
       Collection<ConfiguredTarget> succeeded = new ArrayList<>();
       Collection<ConfiguredTarget> failed = new ArrayList<>();
+      Collection<ConfiguredTarget> skipped = new ArrayList<>();
       Collection<ConfiguredTarget> successfulTargets = result.getSuccessfulTargets();
       for (ConfiguredTarget target : targetsToPrint) {
-        (successfulTargets.contains(target) ? succeeded : failed).add(target);
+        if (configuredTargetsToSkip.contains(target)) {
+          skipped.add(target);
+        } else {
+          (successfulTargets.contains(target) ? succeeded : failed).add(target);
+        }
       }
 
-      // TODO(bazel-team): convert these to a new "SKIPPED" status when ready: b/62191890.
-      failed.addAll(configuredTargetsToSkip);
+      for (ConfiguredTarget target : skipped) {
+        outErr.printErr("Target " + target.getLabel() + " was skipped\n");
+      }
 
       TopLevelArtifactContext context = request.getTopLevelArtifactContext();
       for (ConfiguredTarget target : succeeded) {

src/main/java/com/google/devtools/build/lib/packages/RuleClass.java

@@ -261,6 +261,8 @@ final class RuleErrorException extends Exception {
    */
   public static final String COMPATIBLE_ENVIRONMENT_ATTR = "compatible_with";
 
+  public static final String TARGET_RESTRICTED_TO_ATTR = "target_compatible_with";
+
   /**
    * For Bazel's constraint system: the implicit attribute used to store rule class restriction
    * defaults as specified by {@link Builder#restrictedTo}.
@@ -1405,6 +1407,7 @@ public <TYPE> Builder exemptFromConstraintChecking(String reason) {
       this.supportsConstraintChecking = false;
       attributes.remove(RuleClass.COMPATIBLE_ENVIRONMENT_ATTR);
       attributes.remove(RuleClass.RESTRICTED_ENVIRONMENT_ATTR);
+      attributes.remove(RuleClass.TARGET_RESTRICTED_TO_ATTR);
       return this;
     }