diff options
Diffstat (limited to 'src/main/java/com/google/devtools/build/lib/actions')
5 files changed, 135 insertions, 111 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/actions/Actions.java b/src/main/java/com/google/devtools/build/lib/actions/Actions.java index a3a6ba6b58..5364316f0c 100644 --- a/src/main/java/com/google/devtools/build/lib/actions/Actions.java +++ b/src/main/java/com/google/devtools/build/lib/actions/Actions.java @@ -17,6 +17,7 @@ package com.google.devtools.build.lib.actions; import com.google.common.base.Preconditions; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableMap; +import com.google.common.collect.Iterables; import com.google.common.escape.Escaper; import com.google.common.escape.Escapers; import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException; @@ -24,7 +25,6 @@ import com.google.devtools.build.lib.cmdline.Label; import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe; import com.google.devtools.build.lib.vfs.OsPathPolicy; import com.google.devtools.build.lib.vfs.PathFragment; -import java.util.Collection; import java.util.Comparator; import java.util.HashMap; import java.util.Iterator; @@ -74,39 +74,15 @@ public final class Actions { } // Don't bother to check input and output counts first; the expected result for these tests is // to always be true (i.e., that this method returns true). - if (!artifactsEqualWithoutOwner(actionA.getMandatoryInputs(), actionB.getMandatoryInputs())) { + if (!Iterables.elementsEqual(actionA.getMandatoryInputs(), actionB.getMandatoryInputs())) { return false; } - if (!artifactsEqualWithoutOwner(actionA.getOutputs(), actionB.getOutputs())) { + if (!Iterables.elementsEqual(actionA.getOutputs(), actionB.getOutputs())) { return false; } return true; } - private static boolean artifactsEqualWithoutOwner( - Iterable<Artifact> iterable1, Iterable<Artifact> iterable2) { - if (iterable1 instanceof Collection && iterable2 instanceof Collection) { - Collection<?> collection1 = (Collection<?>) iterable1; - Collection<?> collection2 = (Collection<?>) iterable2; - if (collection1.size() != collection2.size()) { - return false; - } - } - Iterator<Artifact> iterator1 = iterable1.iterator(); - Iterator<Artifact> iterator2 = iterable2.iterator(); - while (iterator1.hasNext()) { - if (!iterator2.hasNext()) { - return false; - } - Artifact artifact1 = iterator1.next(); - Artifact artifact2 = iterator2.next(); - if (!artifact1.equalsWithoutOwner(artifact2)) { - return false; - } - } - return !iterator2.hasNext(); - } - /** * Finds action conflicts. An action conflict happens if two actions generate the same output * artifact. Shared actions are tolerated. See {@link #canBeShared} for details. diff --git a/src/main/java/com/google/devtools/build/lib/actions/Artifact.java b/src/main/java/com/google/devtools/build/lib/actions/Artifact.java index f91c5cde5a..a974646d55 100644 --- a/src/main/java/com/google/devtools/build/lib/actions/Artifact.java +++ b/src/main/java/com/google/devtools/build/lib/actions/Artifact.java @@ -45,7 +45,6 @@ import com.google.devtools.build.lib.util.FileTypeSet; import com.google.devtools.build.lib.vfs.Path; import com.google.devtools.build.lib.vfs.PathFragment; import com.google.devtools.build.skyframe.SkyFunctionName; -import com.google.devtools.build.skyframe.SkyKey; import com.google.protobuf.CodedInputStream; import com.google.protobuf.CodedOutputStream; import java.io.IOException; @@ -108,8 +107,7 @@ public class Artifact ActionInput, FileApi, Comparable<Object>, - CommandLineItem, - SkyKey { + CommandLineItem { /** Compares artifact according to their exec paths. Sorts null values first. */ @SuppressWarnings("ReferenceEquality") // "a == b" is an optimization @@ -228,9 +226,6 @@ public class Artifact throw new IllegalArgumentException( "it is illegal to create an artifact with an empty execPath"); } - // The ArtifactOwner is not part of this computation because it is very rare that two Artifacts - // have the same execPath and different owners, so a collision is fine there. If this is - // changed, OwnerlessArtifactWrapper must also be changed. this.hashCode = execPath.hashCode() + this.getClass().hashCode() * 13; this.root = root; this.execPath = execPath; @@ -458,15 +453,6 @@ public class Artifact public SourceArtifact asSourceArtifact() { return this; } - - /** - * SourceArtifacts are compared without their owners, since owners do not affect behavior, - * unlike with derived artifacts, whose owners determine their generating actions. - */ - @Override - public boolean equals(Object other) { - return other instanceof SourceArtifact && equalsWithoutOwner((SourceArtifact) other); - } } /** @@ -649,26 +635,36 @@ public class Artifact } @Override - public boolean equals(Object other) { + public final boolean equals(Object other) { if (!(other instanceof Artifact)) { return false; } if (!getClass().equals(other.getClass())) { return false; } + // We don't bother to check root in the equivalence relation, because we + // assume that no root is an ancestor of another one. Artifact that = (Artifact) other; - return equalsWithoutOwner(that) && owner.equals(that.getArtifactOwner()); + return Objects.equals(this.execPath, that.execPath) && Objects.equals(this.root, that.root); } - public boolean equalsWithoutOwner(Artifact other) { - return Objects.equals(this.execPath, other.execPath) && Objects.equals(this.root, other.root); + /** + * Compare equality including Artifact owner equality, a notable difference compared to the + * {@link #equals(Object)} method of {@link Artifact}. + */ + public static boolean equalWithOwner(@Nullable Artifact first, @Nullable Artifact second) { + if (first != null) { + return first.equals(second) && first.getArtifactOwner().equals(second.getArtifactOwner()); + } else { + return second == null; + } } @Override public final int hashCode() { - // This is just execPath.hashCode() (along with the class). We cache a copy in the Artifact - // object to reduce LLC misses during operations which build a HashSet out of many Artifacts. - // This is a slight loss for memory but saves ~1% overall CPU in some real builds. + // This is just path.hashCode(). We cache a copy in the Artifact object to reduce LLC misses + // during operations which build a HashSet out of many Artifacts. This is a slight loss for + // memory but saves ~1% overall CPU in some real builds. return hashCode; } @@ -976,33 +972,4 @@ public class Artifact printer.append("<generated file " + rootRelativePath + ">"); } } - - /** - * A utility class that compares {@link Artifact}s without taking their owners into account. - * Should only be used for detecting action conflicts and merging shared action data. - */ - public static class OwnerlessArtifactWrapper { - private final Artifact artifact; - - public OwnerlessArtifactWrapper(Artifact artifact) { - this.artifact = artifact; - } - - @Override - public int hashCode() { - // Depends on the fact that Artifact#hashCode does not use ArtifactOwner. - return artifact.hashCode(); - } - - @Override - public boolean equals(Object obj) { - return obj instanceof OwnerlessArtifactWrapper - && this.artifact.equalsWithoutOwner(((OwnerlessArtifactWrapper) obj).artifact); - } - } - - @Override - public SkyFunctionName functionName() { - return ARTIFACT; - } } diff --git a/src/main/java/com/google/devtools/build/lib/actions/ArtifactSkyKey.java b/src/main/java/com/google/devtools/build/lib/actions/ArtifactSkyKey.java index 701aacaec4..277b26933b 100644 --- a/src/main/java/com/google/devtools/build/lib/actions/ArtifactSkyKey.java +++ b/src/main/java/com/google/devtools/build/lib/actions/ArtifactSkyKey.java @@ -13,52 +13,99 @@ // limitations under the License. package com.google.devtools.build.lib.actions; +import com.google.common.base.Function; import com.google.common.base.Preconditions; +import com.google.common.collect.Collections2; import com.google.common.collect.Interner; +import com.google.common.collect.Iterables; import com.google.devtools.build.lib.concurrent.BlazeInterners; import com.google.devtools.build.lib.concurrent.ThreadSafety; import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec; import com.google.devtools.build.skyframe.SkyFunctionName; import com.google.devtools.build.skyframe.SkyKey; +import java.util.Collection; /** - * A {@link SkyKey} coming from an {@link Artifact} that is not mandatory: absence of the Artifact - * does not imply any error. + * A {@link SkyKey} coming from an {@link Artifact}. Source artifacts are checked for existence, + * while output artifacts imply creation of the output file. * - * <p>Since {@link Artifact} is already a {@link SkyKey}, this wrapper is only needed when the - * {@link Artifact} is not mandatory (discovered during include scanning). + * <p>There are effectively three kinds of output artifact values corresponding to these keys. The + * first corresponds to an ordinary artifact {@link FileArtifactValue}. It stores the relevant data + * for the artifact -- digest/mtime and size. The second corresponds to either an "aggregating" + * artifact -- the output of an aggregating middleman action -- or a TreeArtifact. It stores the + * relevant data of all its inputs, as well as a combined digest for itself. + * + * <p>Artifacts are compared using just their paths, but in Skyframe, the configured target that + * owns an artifact must also be part of the comparison. For example, suppose we build //foo:foo in + * configurationA, yielding artifact foo.out. If we change the configuration to configurationB in + * such a way that the path to the artifact does not change, requesting foo.out from the graph will + * result in the value entry for foo.out under configurationA being returned. This would prevent + * caching the graph in different configurations, and also causes big problems with change pruning, + * which assumes the invariant that a value's first dependency will always be the same. In this + * case, the value entry's old dependency on //foo:foo in configurationA would cause it to request + * (//foo:foo, configurationA) from the graph, causing an undesired re-analysis of (//foo:foo, + * configurationA). + * + * <p>In order to prevent that, instead of just comparing Artifacts, we compare for equality using + * both the Artifact, and the owner. The effect is functionally that of making Artifact.equals() + * check the owner, but only within these keys, since outside of Skyframe it is quite crucial that + * Artifacts with different owners be able to compare equal. */ -// TODO(janakr): pull mandatory/non-mandatory handling up to consumers and get rid of this wrapper. @AutoCodec public class ArtifactSkyKey implements SkyKey { private static final Interner<ArtifactSkyKey> INTERNER = BlazeInterners.newWeakInterner(); + private static final Function<Artifact, ArtifactSkyKey> TO_MANDATORY_KEY = + artifact -> key(artifact, true); + private static final Function<ArtifactSkyKey, Artifact> TO_ARTIFACT = ArtifactSkyKey::getArtifact; - private final Artifact.SourceArtifact artifact; + private final Artifact artifact; + // Always true for derived artifacts. + private final boolean isMandatory; + // TODO(janakr): we may want to remove this field in the future. The expensive hash computation + // is already cached one level down (in the Artifact), so the CPU overhead here may not be + // worth the memory. However, when running with +CompressedOops, this field is free, so we leave + // it. When running with -CompressedOops, we might be able to save memory by using polymorphism + // for isMandatory and dropping this field. + private int hashCode = 0; - private ArtifactSkyKey(Artifact.SourceArtifact sourceArtifact) { + private ArtifactSkyKey(Artifact sourceArtifact, boolean mandatory) { + Preconditions.checkArgument(sourceArtifact.isSourceArtifact()); this.artifact = Preconditions.checkNotNull(sourceArtifact); + this.isMandatory = mandatory; } - @ThreadSafety.ThreadSafe - public static SkyKey key(Artifact artifact, boolean isMandatory) { - if (isMandatory || !artifact.isSourceArtifact()) { - return artifact; - } - return create(((Artifact.SourceArtifact) artifact)); + /** + * Constructs an ArtifactSkyKey for a derived artifact. The mandatory attribute is not needed + * because a derived artifact must be a mandatory input for some action in order to ensure that it + * is built in the first place. If it fails to build, then that fact is cached in the node, so any + * action that has it as a non-mandatory input can retrieve that information from the node. + */ + private ArtifactSkyKey(Artifact derivedArtifact) { + this.artifact = Preconditions.checkNotNull(derivedArtifact); + Preconditions.checkArgument(!derivedArtifact.isSourceArtifact(), derivedArtifact); + this.isMandatory = true; // Unused. } - @AutoCodec.VisibleForSerialization + @ThreadSafety.ThreadSafe @AutoCodec.Instantiator - static ArtifactSkyKey create(Artifact.SourceArtifact artifact) { - return INTERNER.intern(new ArtifactSkyKey(artifact)); + public static ArtifactSkyKey key(Artifact artifact, boolean isMandatory) { + return INTERNER.intern( + artifact.isSourceArtifact() + ? new ArtifactSkyKey(artifact, isMandatory) + : new ArtifactSkyKey(artifact)); } - public static Artifact artifact(SkyKey key) { - return key instanceof Artifact ? (Artifact) key : ((ArtifactSkyKey) key).artifact; + @ThreadSafety.ThreadSafe + public static Iterable<ArtifactSkyKey> mandatoryKeys(Iterable<Artifact> artifacts) { + return Iterables.transform(artifacts, TO_MANDATORY_KEY); } - public static boolean isMandatory(SkyKey key) { - return key instanceof Artifact; + public static Collection<Artifact> artifacts(Collection<? extends ArtifactSkyKey> keys) { + return Collections2.transform(keys, TO_ARTIFACT); + } + + public static Artifact artifact(SkyKey key) { + return TO_ARTIFACT.apply((ArtifactSkyKey) key.argument()); } @Override @@ -68,7 +115,32 @@ public class ArtifactSkyKey implements SkyKey { @Override public int hashCode() { - return artifact.hashCode(); + // We use the hash code caching strategy employed by java.lang.String. There are three subtle + // things going on here: + // + // (1) We use a value of 0 to indicate that the hash code hasn't been computed and cached yet. + // Yes, this means that if the hash code is really 0 then we will "recompute" it each time. + // But this isn't a problem in practice since a hash code of 0 should be rare. + // + // (2) Since we have no synchronization, multiple threads can race here thinking there are the + // first one to compute and cache the hash code. + // + // (3) Moreover, since 'hashCode' is non-volatile, the cached hash code value written from one + // thread may not be visible by another. Note that we probably don't need to worry about + // multiple inefficient reads of 'hashCode' on the same thread since it's non-volatile. + // + // All three of these issues are benign from a correctness perspective; in the end we have no + // overhead from synchronization, at the cost of potentially computing the hash code more than + // once. + if (hashCode == 0) { + hashCode = computeHashCode(); + } + return hashCode; + } + + private int computeHashCode() { + int initialHash = artifact.hashCode() + artifact.getArtifactOwner().hashCode(); + return isMandatory ? initialHash : 47 * initialHash + 1; } @Override @@ -80,13 +152,24 @@ public class ArtifactSkyKey implements SkyKey { return false; } ArtifactSkyKey thatArtifactSkyKey = ((ArtifactSkyKey) that); - return artifact.equals(thatArtifactSkyKey.artifact); + return Artifact.equalWithOwner(artifact, thatArtifactSkyKey.artifact) + && isMandatory == thatArtifactSkyKey.isMandatory; } public Artifact getArtifact() { return artifact; } + /** + * Returns whether the artifact is a mandatory input of its requesting action. May only be called + * for source artifacts, since a derived artifact must be a mandatory input of some action in + * order to have been built in the first place. + */ + public boolean isMandatory() { + Preconditions.checkState(artifact.isSourceArtifact(), artifact); + return isMandatory; + } + @Override public String toString() { return artifact.prettyPrint() + " " + artifact.getArtifactOwner(); diff --git a/src/main/java/com/google/devtools/build/lib/actions/FilesetTraversalParams.java b/src/main/java/com/google/devtools/build/lib/actions/FilesetTraversalParams.java index fca7d2218c..703611fd27 100644 --- a/src/main/java/com/google/devtools/build/lib/actions/FilesetTraversalParams.java +++ b/src/main/java/com/google/devtools/build/lib/actions/FilesetTraversalParams.java @@ -26,7 +26,6 @@ import com.google.devtools.build.lib.util.Fingerprint; import com.google.devtools.build.lib.vfs.PathFragment; import com.google.devtools.build.lib.vfs.Root; import com.google.devtools.build.lib.vfs.RootedPath; -import java.util.Objects; import javax.annotation.Nullable; /** @@ -112,7 +111,9 @@ public interface FilesetTraversalParams { if (o instanceof FilesetTraversalParams.DirectTraversalRoot) { FilesetTraversalParams.DirectTraversalRoot that = (FilesetTraversalParams.DirectTraversalRoot) o; - return Objects.equals(this.getOutputArtifact(), that.getOutputArtifact()) + // Careful! We must compare the artifact owners, which the default {@link Artifact#equals()} + // method does not do. See the comments on {@link ArtifactSkyKey} and http://b/73738481. + return Artifact.equalWithOwner(this.getOutputArtifact(), that.getOutputArtifact()) && (this.getRootPart().equals(that.getRootPart())) && (this.getRelativePart().equals(that.getRelativePart())); } diff --git a/src/main/java/com/google/devtools/build/lib/actions/MapBasedActionGraph.java b/src/main/java/com/google/devtools/build/lib/actions/MapBasedActionGraph.java index dadad155e6..f35f963bf7 100644 --- a/src/main/java/com/google/devtools/build/lib/actions/MapBasedActionGraph.java +++ b/src/main/java/com/google/devtools/build/lib/actions/MapBasedActionGraph.java @@ -15,7 +15,6 @@ package com.google.devtools.build.lib.actions; import com.google.common.base.Preconditions; -import com.google.devtools.build.lib.actions.Artifact.OwnerlessArtifactWrapper; import javax.annotation.Nullable; import javax.annotation.concurrent.ThreadSafe; @@ -25,7 +24,7 @@ import javax.annotation.concurrent.ThreadSafe; @ThreadSafe public final class MapBasedActionGraph implements MutableActionGraph { private final ActionKeyContext actionKeyContext; - private final ConcurrentMultimapWithHeadElement<OwnerlessArtifactWrapper, ActionAnalysisMetadata> + private final ConcurrentMultimapWithHeadElement<Artifact, ActionAnalysisMetadata> generatingActionMap = new ConcurrentMultimapWithHeadElement<>(); public MapBasedActionGraph(ActionKeyContext actionKeyContext) { @@ -35,18 +34,17 @@ public final class MapBasedActionGraph implements MutableActionGraph { @Override @Nullable public ActionAnalysisMetadata getGeneratingAction(Artifact artifact) { - return generatingActionMap.get(new OwnerlessArtifactWrapper(artifact)); + return generatingActionMap.get(artifact); } @Override public void registerAction(ActionAnalysisMetadata action) throws ActionConflictException { for (Artifact artifact : action.getOutputs()) { - OwnerlessArtifactWrapper wrapper = new OwnerlessArtifactWrapper(artifact); - ActionAnalysisMetadata previousAction = generatingActionMap.putAndGet(wrapper, action); + ActionAnalysisMetadata previousAction = generatingActionMap.putAndGet(artifact, action); if (previousAction != null && previousAction != action && !Actions.canBeShared(actionKeyContext, action, previousAction)) { - generatingActionMap.remove(wrapper, action); + generatingActionMap.remove(artifact, action); throw new ActionConflictException(actionKeyContext, artifact, previousAction, action); } } @@ -55,9 +53,8 @@ public final class MapBasedActionGraph implements MutableActionGraph { @Override public void unregisterAction(ActionAnalysisMetadata action) { for (Artifact artifact : action.getOutputs()) { - OwnerlessArtifactWrapper wrapper = new OwnerlessArtifactWrapper(artifact); - generatingActionMap.remove(wrapper, action); - ActionAnalysisMetadata otherAction = generatingActionMap.get(wrapper); + generatingActionMap.remove(artifact, action); + ActionAnalysisMetadata otherAction = generatingActionMap.get(artifact); Preconditions.checkState( otherAction == null || (otherAction != action |