Add skyfunction to return all registered toolchain labels.

Part of #2219.

Change-Id: I7293fd13bd8e0931f92afd051e18a9e7ce63762d
PiperOrigin-RevId: 161721445

src/main/java/com/google/devtools/build/lib/skyframe/RegisteredToolchainsFunction.java

@@ -0,0 +1,141 @@
+// Copyright 2017 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.skyframe;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.analysis.platform.DeclaredToolchainInfo;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.rules.ExternalPackageUtil;
+import com.google.devtools.build.lib.skyframe.ConfiguredTargetFunction.ConfiguredValueCreationException;
+import com.google.devtools.build.skyframe.LegacySkyKey;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+import com.google.devtools.build.skyframe.ValueOrException;
+import java.util.List;
+import java.util.Map;
+import javax.annotation.Nullable;
+
+/**
+ * {@link SkyFunction} that returns all registered toolchains available for toolchain resolution.
+ */
+public class RegisteredToolchainsFunction implements SkyFunction {
+
+  @Nullable
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env)
+      throws SkyFunctionException, InterruptedException {
+
+    BuildConfiguration configuration = (BuildConfiguration) skyKey.argument();
+
+    // Get the registered toolchains.
+    List<Label> registeredToolchainLabels = ExternalPackageUtil.getRegisteredToolchainLabels(env);
+    if (registeredToolchainLabels == null) {
+      return null;
+    }
+
+    // Load the configured target for each, and get the declared toolchain providers.
+    ImmutableList<DeclaredToolchainInfo> registeredToolchains =
+        configureRegisteredToolchains(env, configuration, registeredToolchainLabels);
+    if (env.valuesMissing()) {
+      return null;
+    }
+
+    return RegisteredToolchainsValue.create(registeredToolchains);
+  }
+
+  private ImmutableList<DeclaredToolchainInfo> configureRegisteredToolchains(
+      Environment env, BuildConfiguration configuration, List<Label> labels)
+      throws InterruptedException, RegisteredToolchainsFunctionException {
+    ImmutableList<SkyKey> keys =
+        labels
+            .stream()
+            .map(
+                label ->
+                    LegacySkyKey.create(
+                        SkyFunctions.CONFIGURED_TARGET,
+                        new ConfiguredTargetKey(label, configuration)))
+            .collect(ImmutableList.toImmutableList());
+
+    Map<SkyKey, ValueOrException<ConfiguredValueCreationException>> values =
+        env.getValuesOrThrow(keys, ConfiguredValueCreationException.class);
+    if (env.valuesMissing()) {
+      return null;
+    }
+    ImmutableList.Builder<DeclaredToolchainInfo> toolchains = new ImmutableList.Builder<>();
+    for (SkyKey key : keys) {
+      ConfiguredTargetKey configuredTargetKey = (ConfiguredTargetKey) key.argument();
+      Label toolchainLabel = configuredTargetKey.getLabel();
+      try {
+        ConfiguredTarget target =
+            ((ConfiguredTargetValue) values.get(key).get()).getConfiguredTarget();
+        DeclaredToolchainInfo toolchainInfo = target.getProvider(DeclaredToolchainInfo.class);
+        if (toolchainInfo == null) {
+          throw new RegisteredToolchainsFunctionException(
+              new InvalidTargetException(toolchainLabel), Transience.PERSISTENT);
+        }
+        toolchains.add(toolchainInfo);
+      } catch (ConfiguredValueCreationException e) {
+        throw new RegisteredToolchainsFunctionException(e, Transience.PERSISTENT);
+      }
+    }
+    return toolchains.build();
+  }
+
+  @Nullable
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return null;
+  }
+
+  /**
+   * Used to indicate that the given {@link Label} represents a {@link ConfiguredTarget} which is
+   * not a valid {@link DeclaredToolchainInfo} provider.
+   */
+  public static final class InvalidTargetException extends Exception {
+
+    private final Label invalidLabel;
+
+    public InvalidTargetException(Label invalidLabel) {
+      super(String.format("target '%s' does not provide a toolchain", invalidLabel));
+      this.invalidLabel = invalidLabel;
+    }
+
+    public Label getInvalidLabel() {
+      return invalidLabel;
+    }
+  }
+
+  /**
+   * Used to declare all the exception types that can be wrapped in the exception thrown by {@link
+   * #compute}.
+   */
+  public static class RegisteredToolchainsFunctionException extends SkyFunctionException {
+
+    public RegisteredToolchainsFunctionException(
+        InvalidTargetException cause, Transience transience) {
+      super(cause, transience);
+    }
+
+    public RegisteredToolchainsFunctionException(
+        ConfiguredValueCreationException cause, Transience persistent) {
+      super(cause, persistent);
+    }
+  }
+}

src/main/java/com/google/devtools/build/lib/skyframe/RegisteredToolchainsValue.java

@@ -0,0 +1,42 @@
+// Copyright 2017 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.skyframe;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.analysis.platform.DeclaredToolchainInfo;
+import com.google.devtools.build.skyframe.LegacySkyKey;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+/**
+ * A value which represents every toolchain known to Bazel and available for toolchain resolution.
+ */
+@AutoValue
+public abstract class RegisteredToolchainsValue implements SkyValue {
+
+  /** Returns the {@link SkyKey} for {@link RegisteredToolchainsValue}s. */
+  public static SkyKey key(BuildConfiguration configuration) {
+    return LegacySkyKey.create(SkyFunctions.REGISTERED_TOOLCHAINS, configuration);
+  }
+
+  public static RegisteredToolchainsValue create(
+      Iterable<DeclaredToolchainInfo> registeredToolchains) {
+    return new AutoValue_RegisteredToolchainsValue(ImmutableList.copyOf(registeredToolchains));
+  }
+
+  public abstract ImmutableList<DeclaredToolchainInfo> registeredToolchains();
+}

src/main/java/com/google/devtools/build/lib/skyframe/SkyFunctions.java

@@ -107,6 +107,8 @@ public final class SkyFunctions {
       SkyFunctionName.create("ACTION_TEMPLATE_EXPANSION");
   public static final SkyFunctionName LOCAL_REPOSITORY_LOOKUP =
       SkyFunctionName.create("LOCAL_REPOSITORY_LOOKUP");
+  public static final SkyFunctionName REGISTERED_TOOLCHAINS =
+      SkyFunctionName.create("REGISTERED_TOOLCHAINS");
 
   public static Predicate<SkyKey> isSkyFunction(final SkyFunctionName functionName) {
     return new Predicate<SkyKey>() {

src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java

@@ -455,6 +455,7 @@ private ImmutableMap<SkyFunctionName, SkyFunction> skyFunctions(
         SkyFunctions.ACTION_TEMPLATE_EXPANSION,
         new ActionTemplateExpansionFunction(removeActionsAfterEvaluation));
     map.put(SkyFunctions.LOCAL_REPOSITORY_LOOKUP, new LocalRepositoryLookupFunction());
+    map.put(SkyFunctions.REGISTERED_TOOLCHAINS, new RegisteredToolchainsFunction());
     map.putAll(extraSkyFunctions);
     return map.build();
   }

src/test/java/com/google/devtools/build/lib/analysis/util/BuildViewTestCase.java

@@ -772,6 +772,24 @@ protected FileConfiguredTarget getHostFileConfiguredTarget(String label)
     return (FileConfiguredTarget) getHostConfiguredTarget(label);
   }
 
+  /**
+   * Rewrites the WORKSPACE to have the required boilerplate and the given lines of content.
+   *
+   * <p>Triggers Skyframe to reinitialize everything.
+   */
+  public void rewriteWorkspace(String... lines) throws Exception {
+    scratch.overwriteFile(
+        "WORKSPACE",
+        new ImmutableList.Builder<String>()
+            .addAll(analysisMock.getWorkspaceContents(mockToolsConfig))
+            .addAll(ImmutableList.copyOf(lines))
+            .build());
+
+    invalidatePackages();
+    // Need to re-initialize the workspace status.
+    getSkyframeExecutor().injectWorkspaceStatusData("test");
+  }
+
   /**
    * Create and return a configured scratch rule.
    *

src/test/java/com/google/devtools/build/lib/rules/platform/BUILD

@@ -4,9 +4,14 @@ filegroup(
     visibility = ["//src/test/java/com/google/devtools/build/lib:__pkg__"],
 )
 
+TESTUTIL_SRCS = ["ToolchainTestCase.java"]
+
 java_test(
     name = "PlatformRulesTests",
-    srcs = glob(["*.java"]),
+    srcs = glob(
+        ["*.java"],
+        exclude = TESTUTIL_SRCS,
+    ),
     test_class = "com.google.devtools.build.lib.AllTests",
     deps = [
         "//src/main/java/com/google/devtools/build/lib:build-base",
@@ -26,3 +31,16 @@ java_test(
         "//third_party:truth",
     ],
 )
+
+java_library(
+    name = "testutil",
+    srcs = TESTUTIL_SRCS,
+    visibility = ["//src/test/java/com/google/devtools/build/lib:__subpackages__"],
+    deps = [
+        "//src/main/java/com/google/devtools/build/lib/analysis/platform",
+        "//src/main/java/com/google/devtools/build/lib/cmdline",
+        "//src/test/java/com/google/devtools/build/lib/skylark:testutil",
+        "//third_party:junit4",
+        "//third_party:truth",
+    ],
+)

src/test/java/com/google/devtools/build/lib/rules/platform/ToolchainTestCase.java

@@ -0,0 +1,87 @@
+// Copyright 2017 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.platform;
+
+import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.skylark.util.SkylarkTestCase;
+import org.junit.Before;
+
+/** Utility methods for setting up platform and toolchain related tests. */
+public abstract class ToolchainTestCase extends SkylarkTestCase {
+
+  public Label testToolchainType;
+  public ConstraintSettingInfo setting;
+  public ConstraintValueInfo linuxConstraint;
+  public ConstraintValueInfo macConstraint;
+
+  @Before
+  public void createConstraints() throws Exception {
+    scratch.file(
+        "constraint/BUILD",
+        "constraint_setting(name = 'os')",
+        "constraint_value(name = 'linux',",
+        "    constraint_setting = ':os')",
+        "constraint_value(name = 'mac',",
+        "    constraint_setting = ':os')");
+
+    setting = ConstraintSettingInfo.create(makeLabel("//constraint:os"));
+    linuxConstraint = ConstraintValueInfo.create(setting, makeLabel("//constraint:linux"));
+    macConstraint = ConstraintValueInfo.create(setting, makeLabel("//constraint:mac"));
+  }
+
+  @Before
+  public void createToolchains() throws Exception {
+    rewriteWorkspace(
+        "register_toolchains(", "    '//toolchain:toolchain_1',", "    '//toolchain:toolchain_2')");
+
+    scratch.file(
+        "toolchain/BUILD",
+        "load(':toolchain_def.bzl', 'test_toolchain')",
+        "toolchain_type(name = 'test_toolchain')",
+        "toolchain(",
+        "    name = 'toolchain_1',",
+        "    toolchain_type = ':test_toolchain',",
+        "    exec_compatible_with = ['//constraint:linux'],",
+        "    target_compatible_with = ['//constraint:mac'],",
+        "    toolchain = ':test_toolchain_1')",
+        "toolchain(",
+        "    name = 'toolchain_2',",
+        "    toolchain_type = ':test_toolchain',",
+        "    exec_compatible_with = ['//constraint:mac'],",
+        "    target_compatible_with = ['//constraint:linux'],",
+        "    toolchain = ':test_toolchain_2')",
+        "test_toolchain(",
+        "  name='test_toolchain_1',",
+        "  data = 'foo')",
+        "test_toolchain(",
+        "  name='test_toolchain_2',",
+        "  data = 'bar')");
+    scratch.file(
+        "toolchain/toolchain_def.bzl",
+        "def _impl(ctx):",
+        "  toolchain = platform_common.ToolchainInfo(",
+        "      type = Label('//toolchain:test_toolchain'),",
+        "      data = ctx.attr.data)",
+        "  return [toolchain]",
+        "test_toolchain = rule(",
+        "    implementation = _impl,",
+        "    attrs = {",
+        "       'data': attr.string()})");
+
+    testToolchainType = makeLabel("//toolchain:test_toolchain");
+  }
+}

src/test/java/com/google/devtools/build/lib/skyframe/BUILD

@@ -25,6 +25,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib:vfs",
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
+        "//src/main/java/com/google/devtools/build/lib/rules/platform",
         "//src/main/java/com/google/devtools/build/skyframe",
         "//src/main/java/com/google/devtools/build/skyframe:skyframe-objects",
         "//src/test/java/com/google/devtools/build/lib:actions_testutil",
@@ -69,15 +70,18 @@ java_test(
         "//src/main/java/com/google/devtools/build/lib:util",
         "//src/main/java/com/google/devtools/build/lib:vfs",
         "//src/main/java/com/google/devtools/build/lib/actions",
+        "//src/main/java/com/google/devtools/build/lib/analysis/platform",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/rules/cpp",
+        "//src/main/java/com/google/devtools/build/lib/rules/platform",
         "//src/main/java/com/google/devtools/build/skyframe",
         "//src/main/java/com/google/devtools/build/skyframe:skyframe-objects",
         "//src/test/java/com/google/devtools/build/lib:actions_testutil",
         "//src/test/java/com/google/devtools/build/lib:analysis_testutil",
         "//src/test/java/com/google/devtools/build/lib:foundations_testutil",
         "//src/test/java/com/google/devtools/build/lib:packages_testutil",
         "//src/test/java/com/google/devtools/build/lib:testutil",
+        "//src/test/java/com/google/devtools/build/lib/rules/platform:testutil",
         "//third_party:guava",
         "//third_party:guava-testlib",
         "//third_party:jsr305",