Use toolchain resolution in rule creation.

Part of #2219.

Change-Id: Id4929d5ddcd57b4635af5e513eb9a09f16a78e71
PiperOrigin-RevId: 162634398

1 files changed, 220 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java b/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java
new file mode 100644
index 0000000000..3afe90af6c
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java
@@ -0,0 +1,220 @@
+// 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.base.Joiner;
+import com.google.common.collect.ImmutableBiMap;
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.PlatformConfiguration;
+import com.google.devtools.build.lib.analysis.ToolchainContext;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
+import com.google.devtools.build.lib.analysis.platform.PlatformProviderUtils;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.skyframe.ConfiguredTargetFunction.ConfiguredValueCreationException;
+import com.google.devtools.build.lib.skyframe.RegisteredToolchainsFunction.InvalidTargetException;
+import com.google.devtools.build.lib.skyframe.ToolchainResolutionFunction.NoToolchainFoundException;
+import com.google.devtools.build.lib.skyframe.ToolchainResolutionValue.ToolchainResolutionKey;
+import com.google.devtools.build.lib.syntax.EvalException;
+import com.google.devtools.build.skyframe.LegacySkyKey;
+import com.google.devtools.build.skyframe.SkyFunction.Environment;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.ValueOrException;
+import com.google.devtools.build.skyframe.ValueOrException4;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Common code to create a {@link ToolchainContext} given a set of required toolchain type labels.
+ */
+public class ToolchainUtil {
+
+  /**
+   * Returns a new {@link ToolchainContext}, with the correct toolchain labels based on the results
+   * of the {@link ToolchainResolutionFunction}.
+   */
+  public static ToolchainContext createToolchainContext(
+      Environment env, List<Label> requiredToolchains, BuildConfiguration configuration)
+      throws ToolchainContextException, InterruptedException {
+    ImmutableBiMap<Label, Label> resolvedLabels =
+        resolveToolchainLabels(env, requiredToolchains, configuration);
+    ToolchainContext toolchainContext = ToolchainContext.create(requiredToolchains, resolvedLabels);
+    return toolchainContext;
+  }
+
+  /**
+   * Data class to hold platform descriptors loaded based on the current {@link BuildConfiguration}.
+   */
+  @AutoValue
+  protected abstract static class PlatformDescriptors {
+    abstract PlatformInfo execPlatform();
+
+    abstract PlatformInfo targetPlatform();
+
+    protected static PlatformDescriptors create(
+        PlatformInfo execPlatform, PlatformInfo targetPlatform) {
+      return new AutoValue_ToolchainUtil_PlatformDescriptors(execPlatform, targetPlatform);
+    }
+  }
+
+  private static PlatformDescriptors loadPlatformDescriptors(
+      Environment env, BuildConfiguration configuration)
+      throws InterruptedException, ToolchainContextException {
+    PlatformConfiguration platformConfiguration =
+        configuration.getFragment(PlatformConfiguration.class);
+    Label executionPlatformLabel = platformConfiguration.getExecutionPlatform();
+    Label targetPlatformLabel = platformConfiguration.getTargetPlatforms().get(0);
+
+    SkyKey executionPlatformKey =
+        LegacySkyKey.create(
+            SkyFunctions.CONFIGURED_TARGET,
+            new ConfiguredTargetKey(executionPlatformLabel, configuration));
+    SkyKey targetPlatformKey =
+        LegacySkyKey.create(
+            SkyFunctions.CONFIGURED_TARGET,
+            new ConfiguredTargetKey(targetPlatformLabel, configuration));
+
+    Map<SkyKey, ValueOrException<ConfiguredValueCreationException>> values =
+        env.getValuesOrThrow(
+            ImmutableList.of(executionPlatformKey, targetPlatformKey),
+            ConfiguredValueCreationException.class);
+    if (env.valuesMissing()) {
+      return null;
+    }
+    try {
+      ConfiguredTarget executionPlatformTarget =
+          ((ConfiguredTargetValue) values.get(executionPlatformKey).get()).getConfiguredTarget();
+      ConfiguredTarget targetPlatformTarget =
+          ((ConfiguredTargetValue) values.get(targetPlatformKey).get()).getConfiguredTarget();
+      PlatformInfo execPlatform = PlatformProviderUtils.platform(executionPlatformTarget);
+      PlatformInfo targetPlatform = PlatformProviderUtils.platform(targetPlatformTarget);
+
+      return PlatformDescriptors.create(execPlatform, targetPlatform);
+    } catch (ConfiguredValueCreationException e) {
+      throw new ToolchainContextException(e);
+    }
+  }
+
+  private static ImmutableBiMap<Label, Label> resolveToolchainLabels(
+      Environment env, List<Label> requiredToolchains, BuildConfiguration configuration)
+      throws InterruptedException, ToolchainContextException {
+
+    // If there are no required toolchains, bail out early.
+    if (requiredToolchains.isEmpty()) {
+      return ImmutableBiMap.of();
+    }
+
+    // Load the execution and target platforms for the current configuration.
+    PlatformDescriptors platforms = loadPlatformDescriptors(env, configuration);
+    if (platforms == null) {
+      return null;
+    }
+
+    // Find the toolchains for the required toolchain types.
+    List<SkyKey> registeredToolchainKeys = new ArrayList<>();
+    for (Label toolchainType : requiredToolchains) {
+      registeredToolchainKeys.add(
+          ToolchainResolutionValue.key(
+              configuration, toolchainType, platforms.targetPlatform(), platforms.execPlatform()));
+    }
+
+    Map<
+            SkyKey,
+            ValueOrException4<
+                NoToolchainFoundException, ConfiguredValueCreationException, InvalidTargetException,
+                EvalException>>
+        results =
+            env.getValuesOrThrow(
+                registeredToolchainKeys,
+                NoToolchainFoundException.class,
+                ConfiguredValueCreationException.class,
+                InvalidTargetException.class,
+                EvalException.class);
+    if (env.valuesMissing()) {
+      return null;
+    }
+
+    // Load the toolchains.
+    ImmutableBiMap.Builder<Label, Label> builder = new ImmutableBiMap.Builder<>();
+    List<Label> missingToolchains = new ArrayList<>();
+    for (Map.Entry<
+            SkyKey,
+            ValueOrException4<
+                NoToolchainFoundException, ConfiguredValueCreationException, InvalidTargetException,
+                EvalException>>
+        entry : results.entrySet()) {
+      try {
+        Label requiredToolchainType =
+            ((ToolchainResolutionKey) entry.getKey().argument()).toolchainType();
+        Label toolchainLabel = ((ToolchainResolutionValue) entry.getValue().get()).toolchainLabel();
+        builder.put(requiredToolchainType, toolchainLabel);
+      } catch (NoToolchainFoundException e) {
+        // Save the missing type and continue looping to check for more.
+        missingToolchains.add(e.missingToolchainType());
+      } catch (ConfiguredValueCreationException e) {
+        throw new ToolchainContextException(e);
+      } catch (InvalidTargetException e) {
+        throw new ToolchainContextException(e);
+      } catch (EvalException e) {
+        throw new ToolchainContextException(e);
+      }
+    }
+
+    if (!missingToolchains.isEmpty()) {
+      throw new ToolchainContextException(new UnresolvedToolchainsException(missingToolchains));
+    }
+
+    return builder.build();
+  }
+
+  /** Exception used when a toolchain type is required but no matching toolchain is found. */
+  public static final class UnresolvedToolchainsException extends Exception {
+    private final ImmutableList<Label> missingToolchainTypes;
+
+    public UnresolvedToolchainsException(List<Label> missingToolchainTypes) {
+      super(
+          String.format(
+              "no matching toolchains found for types %s",
+              Joiner.on(", ").join(missingToolchainTypes)));
+      this.missingToolchainTypes = ImmutableList.copyOf(missingToolchainTypes);
+    }
+
+    public ImmutableList<Label> missingToolchainTypes() {
+      return missingToolchainTypes;
+    }
+  }
+
+  /** Exception used to wrap exceptions during toolchain resolution. */
+  public static class ToolchainContextException extends Exception {
+    public ToolchainContextException(UnresolvedToolchainsException e) {
+      super(e);
+    }
+
+    public ToolchainContextException(ConfiguredValueCreationException e) {
+      super(e);
+    }
+
+    public ToolchainContextException(InvalidTargetException e) {
+      super(e);
+    }
+
+    public ToolchainContextException(EvalException e) {
+      super(e);
+    }
+  }
+}