Switch to RunfilesSuppliers for communicating runfiles

ActionSpawn/SpawnAction now deal exclusively in RunfilesSuppliers, manifests
maps are no more.

There is some lingering awkwardness, in particular:
- Manifests still need to be tracked in some places, we can work out if this is
  still necessary on a case by case basis.
- Skylark makes actions' runfiles available via 'resolve_command' where they are
  consumed by 'action'. I've updated the documentation, though the name isn't
  entirely accurate anymore. That being said these interfaces _are_ marked as
  experimental, so we _should_ be able to be flexible here.

Overall, I think the benefits consolidating runfiles into suppliers, from both
code cleanliness and performance perspectives (no longer needing to parse
manifests), outweights the awkwardnesses.

RELNOTES: resolve_command/action's input_manifest return/parameter is now list

--
PiperOrigin-RevId: 145817429
MOS_MIGRATED_REVID=145817429

23 files changed, 227 insertions, 295 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/actions/BaseSpawn.java b/src/main/java/com/google/devtools/build/lib/actions/BaseSpawn.java
index dd2d5de509..6208db67ce 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/BaseSpawn.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/BaseSpawn.java
@@ -14,7 +14,6 @@
 
 package com.google.devtools.build.lib.actions;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
@@ -37,21 +36,15 @@ public class BaseSpawn implements Spawn {
   private final ImmutableList<String> arguments;
   private final ImmutableMap<String, String> environment;
   private final ImmutableMap<String, String> executionInfo;
-  private final ImmutableMap<PathFragment, Artifact> runfilesManifests;
   private final ImmutableSet<PathFragment> optionalOutputFiles;
   private final RunfilesSupplier runfilesSupplier;
   private final ActionExecutionMetadata action;
   private final ResourceSet localResources;
 
-  // TODO(bazel-team): When we migrate ActionSpawn to use this constructor decide on and enforce
-  // policy on runfilesManifests and runfilesSupplier being non-empty (ie: are overlapping mappings
-  // allowed?).
-  @VisibleForTesting
-  BaseSpawn(
+  public BaseSpawn(
       List<String> arguments,
       Map<String, String> environment,
       Map<String, String> executionInfo,
-      Map<PathFragment, Artifact> runfilesManifests,
       RunfilesSupplier runfilesSupplier,
       ActionExecutionMetadata action,
       ResourceSet localResources,
@@ -59,7 +52,6 @@ public class BaseSpawn implements Spawn {
     this.arguments = ImmutableList.copyOf(arguments);
     this.environment = ImmutableMap.copyOf(environment);
     this.executionInfo = ImmutableMap.copyOf(executionInfo);
-    this.runfilesManifests = ImmutableMap.copyOf(runfilesManifests);
     this.runfilesSupplier = runfilesSupplier;
     this.action = action;
     this.localResources = localResources;
@@ -81,35 +73,12 @@ public class BaseSpawn implements Spawn {
         arguments,
         environment,
         executionInfo,
-        ImmutableMap.<PathFragment, Artifact>of(),
         runfilesSupplier,
         action,
         localResources,
         ImmutableSet.<PathFragment>of());
   }
 
-  /**
-   * Returns a new Spawn. The caller must not modify the parameters after the call; neither will
-   * this method.
-   */
-  public BaseSpawn(
-      List<String> arguments,
-      Map<String, String> environment,
-      Map<String, String> executionInfo,
-      Map<PathFragment, Artifact> runfilesManifests,
-      ActionExecutionMetadata action,
-      ResourceSet localResources) {
-    this(
-        arguments,
-        environment,
-        executionInfo,
-        runfilesManifests,
-        EmptyRunfilesSupplier.INSTANCE,
-        action,
-        localResources,
-        ImmutableSet.<PathFragment>of());
-  }
-
   /** Returns a new Spawn. */
   public BaseSpawn(
       List<String> arguments,
@@ -121,30 +90,11 @@ public class BaseSpawn implements Spawn {
         arguments,
         environment,
         executionInfo,
-        ImmutableMap.<PathFragment, Artifact>of(),
+        EmptyRunfilesSupplier.INSTANCE,
         action,
         localResources);
   }
 
-  public BaseSpawn(
-      List<String> arguments,
-      Map<String, String> environment,
-      Map<String, String> executionInfo,
-      RunfilesSupplier runfilesSupplier,
-      ActionExecutionMetadata action,
-      ResourceSet localResources,
-      Collection<PathFragment> optionalOutputFiles) {
-    this(
-        arguments,
-        environment,
-        executionInfo,
-        ImmutableMap.<PathFragment, Artifact>of(),
-        runfilesSupplier,
-        action,
-        localResources,
-        optionalOutputFiles);
-  }
-
   public static PathFragment runfilesForFragment(PathFragment pathFragment) {
     return pathFragment.getParentDirectory().getChild(pathFragment.getBaseName() + ".runfiles");
   }
@@ -170,11 +120,6 @@ public class BaseSpawn implements Spawn {
   }
 
   @Override
-  public ImmutableMap<PathFragment, Artifact> getRunfilesManifests() {
-    return runfilesManifests;
-  }
-
-  @Override
   public RunfilesSupplier getRunfilesSupplier() {
     return runfilesSupplier;
   }
@@ -234,10 +179,8 @@ public class BaseSpawn implements Spawn {
   /** @return the runfiles directory if there is only one, otherwise null */
   private PathFragment getRunfilesRoot() {
     Set<PathFragment> runfilesSupplierRoots = runfilesSupplier.getRunfilesDirs();
-    if (runfilesSupplierRoots.size() == 1 && runfilesManifests.isEmpty()) {
+    if (runfilesSupplierRoots.size() == 1) {
       return Iterables.getOnlyElement(runfilesSupplierRoots);
-    } else if (runfilesManifests.size() == 1 && runfilesSupplierRoots.isEmpty()) {
-      return Iterables.getOnlyElement(runfilesManifests.keySet());
     } else {
       return null;
     }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/CompositeRunfilesSupplier.java b/src/main/java/com/google/devtools/build/lib/actions/CompositeRunfilesSupplier.java
index ae2c465bd8..da119ab009 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/CompositeRunfilesSupplier.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/CompositeRunfilesSupplier.java
@@ -12,52 +12,72 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.devtools.build.lib.analysis;
+package com.google.devtools.build.lib.actions;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Maps;
-import com.google.devtools.build.lib.actions.Artifact;
-import com.google.devtools.build.lib.actions.RunfilesSupplier;
-import com.google.devtools.build.lib.util.Preconditions;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.io.IOException;
 import java.util.Map;
 
-/** RunfilesSupplier implementation composing instances. */
+/** A {@link RunfilesSupplier} implementation for composing multiple instances. */
+// TODO(michajlo): Move creation to factory constructor and optimize structure of the returned
+// supplier, ie: [] -> EmptyRunfilesSupplier, [singleSupplier] -> supplier,
+// [Empty, single] -> single, and so on.
 public class CompositeRunfilesSupplier implements RunfilesSupplier {
 
-  private final RunfilesSupplier first;
-  private final RunfilesSupplier second;
+  private final ImmutableList<RunfilesSupplier> suppliers;
 
   /** Create an instance with {@code first} taking precedence over {@code second}. */
   public CompositeRunfilesSupplier(RunfilesSupplier first, RunfilesSupplier second) {
-    this.first = Preconditions.checkNotNull(first);
-    this.second = Preconditions.checkNotNull(second);
+    this(ImmutableList.of(first, second));
+  }
+
+  /**
+   * Create an instance combining all of {@code suppliers}, with earlier elements taking precedence.
+   */
+  public CompositeRunfilesSupplier(Iterable<RunfilesSupplier> suppliers) {
+    this.suppliers = ImmutableList.copyOf(suppliers);
   }
 
   @Override
   public Iterable<Artifact> getArtifacts() {
     ImmutableSet.Builder<Artifact> result = ImmutableSet.builder();
-    result.addAll(first.getArtifacts());
-    result.addAll(second.getArtifacts());
+    for (RunfilesSupplier supplier : suppliers) {
+      result.addAll(supplier.getArtifacts());
+    }
     return result.build();
   }
 
   @Override
   public ImmutableSet<PathFragment> getRunfilesDirs() {
     ImmutableSet.Builder<PathFragment> result = ImmutableSet.builder();
-    result.addAll(first.getRunfilesDirs());
-    result.addAll(second.getRunfilesDirs());
+    for (RunfilesSupplier supplier : suppliers) {
+      result.addAll(supplier.getRunfilesDirs());
+    }
     return result.build();
   }
 
   @Override
   public ImmutableMap<PathFragment, Map<PathFragment, Artifact>> getMappings() throws IOException {
     Map<PathFragment, Map<PathFragment, Artifact>> result = Maps.newHashMap();
-    result.putAll(second.getMappings());
-    result.putAll(first.getMappings());
+    for (RunfilesSupplier supplier : suppliers) {
+      Map<PathFragment, Map<PathFragment, Artifact>> mappings = supplier.getMappings();
+      for (Map.Entry<PathFragment, Map<PathFragment, Artifact>> entry : mappings.entrySet()) {
+        result.putIfAbsent(entry.getKey(), entry.getValue());
+      }
+    }
     return ImmutableMap.copyOf(result);
   }
+
+  @Override
+  public ImmutableList<Artifact> getManifests() {
+    ImmutableList.Builder<Artifact> result = ImmutableList.builder();
+    for (RunfilesSupplier supplier : suppliers) {
+      result.addAll(supplier.getManifests());
+    }
+    return result.build();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/actions/DelegateSpawn.java b/src/main/java/com/google/devtools/build/lib/actions/DelegateSpawn.java
index 45a1496259..821407bd86 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/DelegateSpawn.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/DelegateSpawn.java
@@ -19,7 +19,6 @@ import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.extra.SpawnInfo;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.util.Collection;
 
 /**
@@ -60,11 +59,6 @@ public class DelegateSpawn implements Spawn {
   }
 
   @Override
-  public ImmutableMap<PathFragment, Artifact> getRunfilesManifests() {
-    return spawn.getRunfilesManifests();
-  }
-
-  @Override
   public RunfilesSupplier getRunfilesSupplier() {
     return spawn.getRunfilesSupplier();
   }
diff --git a/src/main/java/com/google/devtools/build/lib/actions/EmptyRunfilesSupplier.java b/src/main/java/com/google/devtools/build/lib/actions/EmptyRunfilesSupplier.java
index 03da101c7b..9cf6d1b5ff 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/EmptyRunfilesSupplier.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/EmptyRunfilesSupplier.java
@@ -18,7 +18,6 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.util.Map;
 
 /** Empty implementation of RunfilesSupplier */
@@ -43,4 +42,8 @@ public class EmptyRunfilesSupplier implements RunfilesSupplier {
     return ImmutableMap.of();
   }
 
+  @Override
+  public ImmutableList<Artifact> getManifests() {
+    return ImmutableList.<Artifact>of();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/actions/RunfilesSupplier.java b/src/main/java/com/google/devtools/build/lib/actions/RunfilesSupplier.java
index 33938335a4..9b05cb16d5 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/RunfilesSupplier.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/RunfilesSupplier.java
@@ -14,14 +14,16 @@
 
 package com.google.devtools.build.lib.actions;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.io.IOException;
 import java.util.Map;
 
 /** Convenience wrapper around runfiles allowing lazy expansion. */
+// TODO(bazel-team): Ideally we could refer to Runfiles objects directly here, but current package
+// structure makes this difficult. Consider moving things around to make this possible.
 public interface RunfilesSupplier {
 
   /** @return the contained artifacts */
@@ -37,4 +39,7 @@ public interface RunfilesSupplier {
    * @throws IOException
    */
   ImmutableMap<PathFragment, Map<PathFragment, Artifact>> getMappings() throws IOException;
+
+  /** @return the runfiles manifest artifacts, if any. */
+  ImmutableList<Artifact> getManifests();
 }
diff --git a/src/main/java/com/google/devtools/build/lib/actions/Spawn.java b/src/main/java/com/google/devtools/build/lib/actions/Spawn.java
index a069db6209..ae2358f991 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/Spawn.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/Spawn.java
@@ -19,7 +19,6 @@ import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.extra.SpawnInfo;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.util.Collection;
 
 /**
@@ -58,11 +57,6 @@ public interface Spawn {
   String asShellCommand(Path workingDir);
 
   /**
-   * Returns the runfiles data for remote execution. Format is (directory, manifest file).
-   */
-  ImmutableMap<PathFragment, Artifact> getRunfilesManifests();
-
-  /**
    * Returns the {@link RunfilesSupplier} helper encapsulating the runfiles for this spawn.
    */
   RunfilesSupplier getRunfilesSupplier();
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
index c24f659b31..c711787225 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
@@ -21,7 +21,7 @@ import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
 import com.google.devtools.build.lib.actions.Artifact;
-import com.google.devtools.build.lib.actions.BaseSpawn;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.analysis.actions.FileWriteAction;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
@@ -65,11 +65,8 @@ public final class CommandHelper {
   @VisibleForTesting
   public static int maxCommandLength = OS.getCurrent() == OS.WINDOWS ? 8000 : 64000;
 
-  /**
-   *  A map of remote path prefixes and corresponding runfiles manifests for tools
-   *  used by this rule.
-   */
-  private final SkylarkDict<PathFragment, Artifact> remoteRunfileManifestMap;
+  /** {@link RunfilesSupplier}s for tools used by this rule. */
+  private final SkylarkList<RunfilesSupplier> toolsRunfilesSuppliers;
 
   /**
    * Use labelMap for heuristically expanding labels (does not include "outs")
@@ -103,8 +100,7 @@ public final class CommandHelper {
     this.ruleContext = ruleContext;
 
     ImmutableList.Builder<Artifact> resolvedToolsBuilder = ImmutableList.builder();
-    ImmutableMap.Builder<PathFragment, Artifact> remoteRunfileManifestBuilder =
-        ImmutableMap.builder();
+    ImmutableList.Builder<RunfilesSupplier> toolsRunfilesBuilder = ImmutableList.builder();
     Map<Label, Collection<Artifact>> tempLabelMap = new HashMap<>();
 
     for (Map.Entry<Label, ? extends Iterable<Artifact>> entry : labelMap.entrySet()) {
@@ -125,11 +121,7 @@ public final class CommandHelper {
       if (executableArtifact != null) {
         mapGet(tempLabelMap, label).add(executableArtifact);
         // Also send the runfiles when running remotely.
-        Artifact runfilesManifest = tool.getRunfilesManifest();
-        if (runfilesManifest != null) {
-          remoteRunfileManifestBuilder.put(
-              BaseSpawn.runfilesForFragment(executableArtifact.getExecPath()), runfilesManifest);
-        }
+        toolsRunfilesBuilder.add(tool.getRunfilesSupplier());
       } else {
         // Map all depArtifacts to the respective label using the multimaps.
         mapGet(tempLabelMap, label).addAll(files);
@@ -137,7 +129,7 @@ public final class CommandHelper {
     }
 
     this.resolvedTools = SkylarkList.createImmutable(resolvedToolsBuilder.build());
-    this.remoteRunfileManifestMap = SkylarkDict.copyOf(null, remoteRunfileManifestBuilder.build());
+    this.toolsRunfilesSuppliers = SkylarkList.createImmutable(toolsRunfilesBuilder.build());
     ImmutableMap.Builder<Label, ImmutableCollection<Artifact>> labelMapBuilder =
         ImmutableMap.builder();
     for (Entry<Label, Collection<Artifact>> entry : tempLabelMap.entrySet()) {
@@ -150,8 +142,8 @@ public final class CommandHelper {
     return resolvedTools;
   }
 
-  public SkylarkDict<PathFragment, Artifact> getRemoteRunfileManifestMap() {
-    return remoteRunfileManifestMap;
+  public SkylarkList<RunfilesSupplier> getToolsRunfilesSuppliers() {
+    return toolsRunfilesSuppliers;
   }
 
   // Returns the value in the specified corresponding to 'key', creating and
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RunfilesSupplierImpl.java b/src/main/java/com/google/devtools/build/lib/analysis/RunfilesSupplierImpl.java
index 474784c5a7..79ecce1b46 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RunfilesSupplierImpl.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RunfilesSupplierImpl.java
@@ -14,7 +14,8 @@
 
 package com.google.devtools.build.lib.analysis;
 
-import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
@@ -22,17 +23,17 @@ import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.BaseSpawn;
 import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.io.IOException;
 import java.util.Map;
-import java.util.Map.Entry;
+import javax.annotation.Nullable;
 
-/**
- * {@link RunfilesSupplier} implementation wrapping directory to {@link Runfiles} objects mappings.
- */
+/** {@link RunfilesSupplier} implementation wrapping a single {@link Runfiles} directory mapping. */
+// TODO(bazel-team): Consider renaming to SingleRunfilesSupplierImpl.
 public class RunfilesSupplierImpl implements RunfilesSupplier {
-
-  private final ImmutableMap<PathFragment, Runfiles> inputRunfiles;
+  private final PathFragment runfilesDir;
+  private final Runfiles runfiles;
+  @Nullable
+  private final Artifact manifest;
 
   /**
    * Create an instance for an executable.
@@ -46,43 +47,48 @@ public class RunfilesSupplierImpl implements RunfilesSupplier {
   }
 
   /**
-   * Create an instance when you have a a single mapping.
-   *
-   * @param runfilesDir the desired runfiles directory. Should be relative.
-   * @param runfiles the runfiles for runfilesDir
+   * Create an instance. When a manifest is available consider using
+   * {@link #RunfilesSupplierImpl(PathFragment, Runfiles, Artifact)} instead.
    */
   public RunfilesSupplierImpl(PathFragment runfilesDir, Runfiles runfiles) {
-    this.inputRunfiles = ImmutableMap.of(runfilesDir, runfiles);
+    this(runfilesDir, runfiles, /*manifest=*/ null);
   }
 
-  @VisibleForTesting
-  public RunfilesSupplierImpl(Map<PathFragment, Runfiles> inputRunfiles) {
-    this.inputRunfiles = ImmutableMap.copyOf(inputRunfiles);
+  /**
+   * Create an instance mapping {@code runfiles} to {@code runfilesDir}.
+   *
+   * @param runfilesDir the desired runfiles directory. Should be relative.
+   * @param runfiles the runfiles for runilesDir.
+   * @param manifest runfiles' associated runfiles manifest artifact, if present.
+   */
+  public RunfilesSupplierImpl(
+      PathFragment runfilesDir,
+      Runfiles runfiles,
+      @Nullable Artifact manifest) {
+    this.runfilesDir = Preconditions.checkNotNull(runfilesDir);
+    this.runfiles = Preconditions.checkNotNull(runfiles);
+    this.manifest = manifest;
   }
 
   @Override
   public Iterable<Artifact> getArtifacts() {
-    ImmutableSet.Builder<Artifact> builder = ImmutableSet.builder();
-    for (Entry<PathFragment, Runfiles> entry : inputRunfiles.entrySet()) {
-      builder.addAll(
-          Iterables.filter(entry.getValue().getAllArtifacts(), Artifact.MIDDLEMAN_FILTER));
-    }
-    return builder.build();
+    return Iterables.filter(runfiles.getAllArtifacts(), Artifact.MIDDLEMAN_FILTER);
   }
 
   @Override
   public ImmutableSet<PathFragment> getRunfilesDirs() {
-    return inputRunfiles.keySet();
+    return ImmutableSet.of(runfilesDir);
   }
 
   @Override
   public ImmutableMap<PathFragment, Map<PathFragment, Artifact>> getMappings() throws IOException {
-    ImmutableMap.Builder<PathFragment, Map<PathFragment, Artifact>> result =
-        ImmutableMap.builder();
-    for (Entry<PathFragment, Runfiles> entry : inputRunfiles.entrySet()) {
-      result.put(entry.getKey(), entry.getValue().getRunfilesInputs(null, null));
-    }
-    return result.build();
+    return ImmutableMap.of(
+        runfilesDir,
+        runfiles.getRunfilesInputs(/*eventHandler=*/ null, /*location=*/ null));
   }
 
+  @Override
+  public ImmutableList<Artifact> getManifests() {
+    return manifest != null ? ImmutableList.of(manifest) : ImmutableList.<Artifact>of();
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java b/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java
index ff4231f989..7004e29b92 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java
@@ -107,6 +107,11 @@ public final class SourceManifestAction extends AbstractFileWriteAction {
     this.runfiles = runfiles;
   }
 
+  /** The {@link Runfiles} for which this action creates the symlink tree. */
+  public Runfiles getGeneratedRunfiles() {
+    return runfiles;
+  }
+
   @VisibleForTesting
   public void writeOutputFile(OutputStream out, EventHandler eventHandler)
       throws IOException {
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/actions/PopulateTreeArtifactAction.java b/src/main/java/com/google/devtools/build/lib/analysis/actions/PopulateTreeArtifactAction.java
index 4339a02dc8..ba7da944b2 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/actions/PopulateTreeArtifactAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/actions/PopulateTreeArtifactAction.java
@@ -33,6 +33,7 @@ import com.google.devtools.build.lib.actions.BaseSpawn;
 import com.google.devtools.build.lib.actions.ExecException;
 import com.google.devtools.build.lib.actions.Executor;
 import com.google.devtools.build.lib.actions.ResourceSet;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.actions.Spawn;
 import com.google.devtools.build.lib.actions.SpawnActionContext;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
@@ -40,9 +41,9 @@ import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.util.Preconditions;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.PathFragment;
-
 import java.io.IOException;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -123,13 +124,13 @@ public final class PopulateTreeArtifactAction extends AbstractAction {
         Artifact treeArtifact,
         Iterable<PathFragment> entriesToExtract,
         Iterable<String> commandLine,
-        Map<PathFragment, Artifact> runfilesManifests,
+        RunfilesSupplier runfilesSupplier,
         ActionExecutionMetadata action) {
       super(
         ImmutableList.copyOf(commandLine),
         ImmutableMap.<String, String>of(),
         ImmutableMap.<String, String>of(),
-        ImmutableMap.copyOf(runfilesManifests),
+        runfilesSupplier,
         action,
         AbstractAction.DEFAULT_RESOURCE_SET);
       this.treeArtifact = treeArtifact;
@@ -212,13 +213,12 @@ public final class PopulateTreeArtifactAction extends AbstractAction {
     f.addString(GUID);
     f.addString(getMnemonic());
     f.addStrings(spawnCommandLine());
-    Map<PathFragment, Artifact> zipperManifest = zipperExecutableRunfilesManifest();
-    f.addInt(zipperManifest.size());
-    for (Map.Entry<PathFragment, Artifact> input : zipperManifest.entrySet()) {
-      f.addString(input.getKey().getPathString() + "/");
-      f.addPath(input.getValue().getExecPath());
+    f.addPaths(zipper.getRunfilesSupplier().getRunfilesDirs());
+    List<Artifact> runfilesManifests = zipper.getRunfilesSupplier().getManifests();
+    f.addInt(runfilesManifests.size());
+    for (Artifact manifest : runfilesManifests) {
+      f.addPath(manifest.getExecPath());
     }
-
     return f.hexDigestAndReset();
   }
 
@@ -255,7 +255,7 @@ public final class PopulateTreeArtifactAction extends AbstractAction {
         outputTreeArtifact,
         entries,
         spawnCommandLine(),
-        zipperExecutableRunfilesManifest(),
+        zipper.getRunfilesSupplier(),
         this);
   }
 
@@ -269,16 +269,6 @@ public final class PopulateTreeArtifactAction extends AbstractAction {
         "@" + archiveManifest.getExecPathString());
   }
 
-  private Map<PathFragment, Artifact> zipperExecutableRunfilesManifest() {
-    if (zipper.getRunfilesManifest() != null) {
-      return ImmutableMap.of(
-          BaseSpawn.runfilesForFragment(zipper.getExecutable().getExecPath()),
-          zipper.getRunfilesManifest());
-    } else {
-      return ImmutableMap.<PathFragment, Artifact>of();
-    }
-  }
-
   private Iterable<PathFragment> readAndCheckManifestEntries()
       throws IOException, IllegalManifestFileException {
     ImmutableList.Builder<PathFragment> manifestEntries = ImmutableList.builder();
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java b/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java
index b7a094a469..cf0f4ebaaf 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java
@@ -32,11 +32,14 @@ import com.google.devtools.build.lib.actions.ActionOwner;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.BaseSpawn;
 import com.google.devtools.build.lib.actions.CommandAction;
+import com.google.devtools.build.lib.actions.CompositeRunfilesSupplier;
+import com.google.devtools.build.lib.actions.EmptyRunfilesSupplier;
 import com.google.devtools.build.lib.actions.ExecException;
 import com.google.devtools.build.lib.actions.ExecutionInfoSpecifier;
 import com.google.devtools.build.lib.actions.Executor;
 import com.google.devtools.build.lib.actions.ParameterFile.ParameterFileType;
 import com.google.devtools.build.lib.actions.ResourceSet;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.actions.Spawn;
 import com.google.devtools.build.lib.actions.SpawnActionContext;
 import com.google.devtools.build.lib.actions.extra.ExtraActionInfo;
@@ -90,8 +93,6 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
   private final boolean executeUnconditionally;
   private final String progressMessage;
   private final String mnemonic;
-  // entries are (directory for remote execution, Artifact)
-  private final ImmutableMap<PathFragment, Artifact> inputManifests;
 
   private final ResourceSet resourceSet;
   private final ImmutableMap<String, String> environment;
@@ -142,7 +143,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
         ImmutableSet.copyOf(clientEnvironmentVariables),
         ImmutableMap.<String, String>of(),
         progressMessage,
-        ImmutableMap.<PathFragment, Artifact>of(),
+        EmptyRunfilesSupplier.INSTANCE,
         mnemonic,
         false,
         null);
@@ -169,8 +170,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
    *     dependency checking; typically it may include the names of input and output files, but this
    *     is not necessary.
    * @param progressMessage the message printed during the progression of the build
-   * @param inputManifests entries in inputs that are symlink manifest files. These are passed to
-   *     remote execution in the environment rather than as inputs.
+   * @param runfilesSupplier {@link RunfilesSupplier}s describing the runfiles for the action
    * @param mnemonic the mnemonic that is reported in the master log.
    */
   public SpawnAction(
@@ -184,18 +184,17 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
       ImmutableSet<String> clientEnvironmentVariables,
       ImmutableMap<String, String> executionInfo,
       String progressMessage,
-      ImmutableMap<PathFragment, Artifact> inputManifests,
+      RunfilesSupplier runfilesSupplier,
       String mnemonic,
       boolean executeUnconditionally,
       ExtraActionInfoSupplier<?> extraActionInfoSupplier) {
-    super(owner, tools, inputs, outputs);
+    super(owner, tools, inputs, runfilesSupplier, outputs);
     this.resourceSet = resourceSet;
     this.executionInfo = executionInfo;
     this.environment = environment;
     this.clientEnvironmentVariables = clientEnvironmentVariables;
     this.argv = argv;
     this.progressMessage = progressMessage;
-    this.inputManifests = inputManifests;
     this.mnemonic = mnemonic;
     this.executeUnconditionally = executeUnconditionally;
     this.extraActionInfoSupplier = extraActionInfoSupplier;
@@ -288,10 +287,6 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
     }
   }
 
-  public ImmutableMap<PathFragment, Artifact> getInputManifests() {
-    return inputManifests;
-  }
-
   /**
    * Returns s, truncated to no more than maxLen characters, appending an
    * ellipsis if truncation occurred.
@@ -308,7 +303,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
    *
    * This method is final, as it is merely a shorthand use of the generic way to obtain a spawn,
    * which also depends on the client environment. Subclasses that which to override the way to get
-   * a spawn should override {@link getSpawn(Map<String, String>)} instead.
+   * a spawn should override {@link #getSpawn(Map)} instead.
    */
   public final Spawn getSpawn() {
     return getSpawn(null);
@@ -331,10 +326,11 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
     // We don't need the toolManifests here, because they are a subset of the inputManifests by
     // definition and the output of an action shouldn't change whether something is considered a
     // tool or not.
-    f.addInt(inputManifests.size());
-    for (Map.Entry<PathFragment, Artifact> input : inputManifests.entrySet()) {
-      f.addString(input.getKey().getPathString() + "/");
-      f.addPath(input.getValue().getExecPath());
+    f.addPaths(getRunfilesSupplier().getRunfilesDirs());
+    ImmutableList<Artifact> runfilesManifests = getRunfilesSupplier().getManifests();
+    f.addInt(runfilesManifests.size());
+    for (Artifact runfilesManifest : runfilesManifests) {
+      f.addPath(runfilesManifest.getExecPath());
     }
     f.addStringMap(getEnvironment());
     f.addStrings(getClientEnvironmentVariables());
@@ -445,7 +441,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
       super(ImmutableList.copyOf(argv.arguments()),
           ImmutableMap.<String, String>of(),
           executionInfo,
-          inputManifests,
+          SpawnAction.this.getRunfilesSupplier(),
           SpawnAction.this,
           resourceSet);
       for (Artifact input : getInputs()) {
@@ -483,7 +479,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
       // included as manifests in getEnvironment().
       List<Artifact> inputs = Lists.newArrayList(getInputs());
       inputs.removeAll(filesets);
-      inputs.removeAll(inputManifests.values());
+      inputs.removeAll(this.getRunfilesSupplier().getManifests());
       return inputs;
     }
   }
@@ -496,8 +492,8 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
     private final NestedSetBuilder<Artifact> toolsBuilder = NestedSetBuilder.stableOrder();
     private final NestedSetBuilder<Artifact> inputsBuilder = NestedSetBuilder.stableOrder();
     private final List<Artifact> outputs = new ArrayList<>();
-    private final Map<PathFragment, Artifact> toolManifests = new LinkedHashMap<>();
-    private final Map<PathFragment, Artifact> inputManifests = new LinkedHashMap<>();
+    private final List<RunfilesSupplier> inputRunfilesSuppliers = new ArrayList<>();
+    private final List<RunfilesSupplier> toolRunfilesSuppliers = new ArrayList<>();
     private ResourceSet resourceSet = AbstractAction.DEFAULT_RESOURCE_SET;
     private ImmutableMap<String, String> environment = ImmutableMap.of();
     private ImmutableSet<String> clientEnvironmentVariables = ImmutableSet.of();
@@ -529,8 +525,8 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
       this.toolsBuilder.addTransitive(other.toolsBuilder.build());
       this.inputsBuilder.addTransitive(other.inputsBuilder.build());
       this.outputs.addAll(other.outputs);
-      this.toolManifests.putAll(other.toolManifests);
-      this.inputManifests.putAll(other.inputManifests);
+      this.inputRunfilesSuppliers.addAll(other.inputRunfilesSuppliers);
+      this.toolRunfilesSuppliers.addAll(other.toolRunfilesSuppliers);
       this.resourceSet = other.resourceSet;
       this.environment = other.environment;
       this.clientEnvironmentVariables = other.clientEnvironmentVariables;
@@ -657,10 +653,6 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
               .addTransitive(tools)
               .build();
 
-      LinkedHashMap<PathFragment, Artifact> inputAndToolManifests =
-          new LinkedHashMap<>(inputManifests);
-      inputAndToolManifests.putAll(toolManifests);
-
       Map<String, String> env;
       Set<String> clientEnv;
       if (useDefaultShellEnvironment) {
@@ -689,7 +681,8 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
           ImmutableSet.copyOf(clientEnv),
           ImmutableMap.copyOf(executionInfo),
           progressMessage,
-          ImmutableMap.copyOf(inputAndToolManifests),
+          new CompositeRunfilesSupplier(
+              Iterables.concat(this.inputRunfilesSuppliers, this.toolRunfilesSuppliers)),
           mnemonic);
     }
 
@@ -705,7 +698,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
         ImmutableSet<String> clientEnvironmentVariables,
         ImmutableMap<String, String> executionInfo,
         String progressMessage,
-        ImmutableMap<PathFragment, Artifact> inputAndToolManifests,
+        RunfilesSupplier runfilesSupplier,
         String mnemonic) {
       return new SpawnAction(
           owner,
@@ -718,7 +711,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
           clientEnvironmentVariables,
           executionInfo,
           progressMessage,
-          inputAndToolManifests,
+          runfilesSupplier,
           mnemonic,
           executeUnconditionally,
           extraActionInfoSupplier);
@@ -790,13 +783,8 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
       return this;
     }
 
-    private Builder addToolManifest(Artifact artifact, PathFragment remote) {
-      toolManifests.put(remote, artifact);
-      return this;
-    }
-
-    public Builder addInputManifest(Artifact artifact, PathFragment remote) {
-      inputManifests.put(remote, artifact);
+    public Builder addRunfilesSupplier(RunfilesSupplier supplier) {
+      inputRunfilesSuppliers.add(supplier);
       return this;
     }
 
@@ -1007,11 +995,7 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
      */
     public Builder addTool(FilesToRunProvider tool) {
       addTools(tool.getFilesToRun());
-      if (tool.getRunfilesManifest() != null) {
-        addToolManifest(
-            tool.getRunfilesManifest(),
-            BaseSpawn.runfilesForFragment(tool.getExecutable().getExecPath()));
-      }
+      toolRunfilesSuppliers.add(tool.getRunfilesSupplier());
       return this;
     }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java
index c58334d450..6792e4e3f7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java
@@ -18,6 +18,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.Action;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.actions.extra.SpawnInfo;
 import com.google.devtools.build.lib.analysis.AbstractConfiguredTarget;
 import com.google.devtools.build.lib.analysis.CommandHelper;
@@ -196,14 +197,16 @@ public class SkylarkRuleImplementationFunctions {
                 + "for useful keys."
       ),
       @Param(
+        // TODO(bazel-team): The name here isn't accurate anymore. This is technically experimental,
+        // so folks shouldn't be too attached, but consider renaming to be more accurate/opaque.
         name = "input_manifests",
-        type = SkylarkDict.class,
+        type = SkylarkList.class,
         noneable = true,
         defaultValue = "None",
         named = true,
         positional = false,
         doc =
-            "sets the map of input manifests files; "
+            "(Experimental) sets the input runfiles metadata; "
                 + "they are typically generated by resolve_command."
       )
     },
@@ -317,14 +320,9 @@ public class SkylarkRuleImplementationFunctions {
                         "execution_requirements")));
           }
           if (inputManifestsUnchecked != Runtime.NONE) {
-            for (Map.Entry<PathFragment, Artifact> entry :
-                SkylarkDict.castSkylarkDictOrNoneToDict(
-                        inputManifestsUnchecked,
-                        PathFragment.class,
-                        Artifact.class,
-                        "input manifest file map")
-                    .entrySet()) {
-              builder.addInputManifest(entry.getValue(), entry.getKey());
+            for (RunfilesSupplier supplier : SkylarkList.castSkylarkListOrNoneToList(
+                inputManifestsUnchecked, RunfilesSupplier.class, "runfiles suppliers")) {
+              builder.addRunfilesSupplier(supplier);
             }
           }
           // Always register the action
@@ -465,7 +463,7 @@ public class SkylarkRuleImplementationFunctions {
             throws EvalException, ConversionException {
           RuleContext ruleContext = ctx.getRuleContext();
           Action action =
-              new PseudoAction<SpawnInfo>(
+              new PseudoAction<>(
                   generateUuid(ruleContext),
                   ruleContext.getActionOwner(),
                   convertInputs(inputs),
@@ -661,7 +659,7 @@ public class SkylarkRuleImplementationFunctions {
   private static Map<Label, Iterable<Artifact>> checkLabelDict(
       Map<?, ?> labelDict, Location loc)
       throws EvalException {
-    Map<Label, Iterable<Artifact>> convertedMap = new HashMap<Label, Iterable<Artifact>>();
+    Map<Label, Iterable<Artifact>> convertedMap = new HashMap<>();
     for (Map.Entry<?, ?> entry : labelDict.entrySet()) {
       Object key = entry.getKey();
       if (!(key instanceof Label)) {
@@ -695,12 +693,14 @@ public class SkylarkRuleImplementationFunctions {
 
   @SkylarkSignature(
     name = "resolve_command",
+    // TODO(bazel-team): The naming here isn't entirely accurate (input_manifests is no longer
+    // manifests), but this is experimental/should be opaque to the end user.
     doc =
         "<i>(Experimental)</i> "
             + "Returns a tuple <code>(inputs, command, input_manifests)</code> of the list of "
-            + "resolved inputs, the argv list for the resolved command, and the dict mapping "
-            + "locations to runfiles required to run the command, all of them suitable for passing "
-            + "as the same-named arguments of the <code>ctx.action</code> method.",
+            + "resolved inputs, the argv list for the resolved command, and the runfiles metadata"
+            + "required to run the command, all of them suitable for passing as the same-named "
+            + "arguments of the <code>ctx.action</code> method.",
     objectType = SkylarkRuleContext.class,
     returnType = Tuple.class,
     parameters = {
@@ -823,7 +823,7 @@ public class SkylarkRuleImplementationFunctions {
           return Tuple.<Object>of(
               new MutableList(inputs, env),
               new MutableList(argv, env),
-              helper.getRemoteRunfileManifestMap());
+              helper.getToolsRunfilesSuppliers());
         }
       };
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/ApkActionsBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/android/ApkActionsBuilder.java
index c483878551..7b03534760 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/ApkActionsBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/ApkActionsBuilder.java
@@ -16,12 +16,15 @@ package com.google.devtools.build.lib.rules.android;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.Runfiles;
+import com.google.devtools.build.lib.analysis.RunfilesSupplierImpl;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.rules.android.AndroidConfiguration.ApkSigningMethod;
 import com.google.devtools.build.lib.rules.java.JavaHelper;
 import com.google.devtools.build.lib.rules.java.JavaToolchainProvider;
 import com.google.devtools.build.lib.rules.java.Jvm;
+import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.Map;
 
@@ -189,12 +192,19 @@ public class ApkActionsBuilder {
           .addInputArgument(javaResourceZip);
     }
 
-    Artifact nativeSymlinks = nativeLibs.createApkBuilderSymlinks(ruleContext);
-    if (nativeSymlinks != null) {
-      PathFragment nativeSymlinksDir = nativeSymlinks.getExecPath().getParentDirectory();
+    Pair<Artifact, Runfiles> nativeSymlinksManifestAndRunfiles =
+        nativeLibs.createApkBuilderSymlinks(ruleContext);
+    if (nativeSymlinksManifestAndRunfiles != null) {
+      Artifact nativeSymlinksManifest = nativeSymlinksManifestAndRunfiles.first;
+      Runfiles nativeSymlinksRunfiles = nativeSymlinksManifestAndRunfiles.second;
+      PathFragment nativeSymlinksDir = nativeSymlinksManifest.getExecPath().getParentDirectory();
       actionBuilder
-          .addInputManifest(nativeSymlinks, nativeSymlinksDir)
-          .addInput(nativeSymlinks)
+          .addRunfilesSupplier(
+              new RunfilesSupplierImpl(
+                  nativeSymlinksDir,
+                  nativeSymlinksRunfiles,
+                  nativeSymlinksManifest))
+          .addInput(nativeSymlinksManifest)
           .addInputs(nativeLibs.getAllNativeLibs())
           .addArgument("-nf")
           // If the native libs are "foo/bar/x86/foo.so", we need to pass "foo/bar" here
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/NativeLibs.java b/src/main/java/com/google/devtools/build/lib/rules/android/NativeLibs.java
index 3dadd0abf1..b5a8c5f6c6 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/NativeLibs.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/NativeLibs.java
@@ -20,6 +20,7 @@ import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Multimap;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.Runfiles;
 import com.google.devtools.build.lib.analysis.SourceManifestAction;
 import com.google.devtools.build.lib.analysis.SourceManifestAction.ManifestType;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
@@ -33,6 +34,7 @@ import com.google.devtools.build.lib.rules.cpp.CcToolchainProvider;
 import com.google.devtools.build.lib.rules.cpp.CppFileTypes;
 import com.google.devtools.build.lib.rules.cpp.LinkerInput;
 import com.google.devtools.build.lib.rules.nativedeps.NativeDepsHelper;
+import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.Collection;
 import java.util.HashMap;
@@ -132,7 +134,7 @@ public final class NativeLibs {
     return result.build();
   }
 
-  public Artifact createApkBuilderSymlinks(RuleContext ruleContext) {
+  public Pair<Artifact, Runfiles> createApkBuilderSymlinks(RuleContext ruleContext) {
     Map<PathFragment, Artifact> symlinks = new LinkedHashMap<>();
     for (Map.Entry<String, Iterable<Artifact>> entry : nativeLibs.entrySet()) {
       String arch = entry.getKey();
@@ -146,11 +148,12 @@ public final class NativeLibs {
     }
 
     Artifact inputManifest = AndroidBinary.getDxArtifact(ruleContext, "native_symlinks.manifest");
-    ruleContext.registerAction(new SourceManifestAction.Builder(
+    SourceManifestAction sourceManifestAction = new SourceManifestAction.Builder(
         ruleContext.getWorkspaceName(), ManifestType.SOURCE_SYMLINKS, ruleContext.getActionOwner(),
         inputManifest, ruleContext.getConfiguration().legacyExternalRunfiles())
             .addRootSymlinks(symlinks)
-            .build());
+            .build();
+    ruleContext.registerAction(sourceManifestAction);
     Artifact outputManifest = AndroidBinary.getDxArtifact(ruleContext, "native_symlinks/MANIFEST");
     Artifact nativeLibsMiddleman =
         ruleContext.getAnalysisEnvironment().getMiddlemanFactory().createRunfilesMiddleman(
@@ -167,7 +170,7 @@ public final class NativeLibs {
             false,
             ruleContext.getConfiguration().getLocalShellEnvironment(),
             ruleContext.getConfiguration().runfilesEnabled()));
-    return outputManifest;
+    return Pair.of(outputManifest, sourceManifestAction.getGeneratedRunfiles());
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendAction.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendAction.java
index e7f9411d0e..9e7b85684b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/LTOBackendAction.java
@@ -26,6 +26,7 @@ import com.google.devtools.build.lib.actions.ArtifactResolver;
 import com.google.devtools.build.lib.actions.PackageRootResolutionException;
 import com.google.devtools.build.lib.actions.PackageRootResolver;
 import com.google.devtools.build.lib.actions.ResourceSet;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.analysis.actions.CommandLine;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
@@ -77,7 +78,7 @@ public final class LTOBackendAction extends SpawnAction {
       Set<String> clientEnvironmentVariables,
       Map<String, String> executionInfo,
       String progressMessage,
-      ImmutableMap<PathFragment, Artifact> inputManifests,
+      RunfilesSupplier runfilesSupplier,
       String mnemonic) {
     super(
         owner,
@@ -90,7 +91,7 @@ public final class LTOBackendAction extends SpawnAction {
         ImmutableSet.copyOf(clientEnvironmentVariables),
         ImmutableMap.copyOf(executionInfo),
         progressMessage,
-        ImmutableMap.copyOf(inputManifests),
+        runfilesSupplier,
         mnemonic,
         false,
         null);
@@ -201,10 +202,10 @@ public final class LTOBackendAction extends SpawnAction {
     f.addString(GUID);
     f.addStrings(getArguments());
     f.addString(getMnemonic());
-    f.addInt(getInputManifests().size());
-    for (Map.Entry<PathFragment, Artifact> input : getInputManifests().entrySet()) {
-      f.addString(input.getKey().getPathString() + "/");
-      f.addPath(input.getValue().getExecPath());
+    f.addPaths(getRunfilesSupplier().getRunfilesDirs());
+    ImmutableList<Artifact> runfilesManifests = getRunfilesSupplier().getManifests();
+    for (Artifact runfilesManifest : runfilesManifests) {
+      f.addPath(runfilesManifest.getExecPath());
     }
     for (Artifact input : getMandatoryInputs()) {
       f.addPath(input.getExecPath());
@@ -242,7 +243,7 @@ public final class LTOBackendAction extends SpawnAction {
         ImmutableSet<String> clientEnvironmentVariables,
         ImmutableMap<String, String> executionInfo,
         String progressMessage,
-        ImmutableMap<PathFragment, Artifact> inputAndToolManifests,
+        RunfilesSupplier runfilesSupplier,
         String mnemonic) {
       return new LTOBackendAction(
           inputsAndTools.toCollection(),
@@ -255,7 +256,7 @@ public final class LTOBackendAction extends SpawnAction {
           clientEnvironmentVariables,
           executionInfo,
           progressMessage,
-          inputAndToolManifests,
+          runfilesSupplier,
           mnemonic);
     }
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java
index d80c5812e4..f9e461661f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraAction.java
@@ -26,9 +26,11 @@ import com.google.devtools.build.lib.actions.ActionExecutionContext;
 import com.google.devtools.build.lib.actions.ActionExecutionException;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.ArtifactResolver;
+import com.google.devtools.build.lib.actions.CompositeRunfilesSupplier;
 import com.google.devtools.build.lib.actions.DelegateSpawn;
 import com.google.devtools.build.lib.actions.PackageRootResolutionException;
 import com.google.devtools.build.lib.actions.PackageRootResolver;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.actions.Spawn;
 import com.google.devtools.build.lib.actions.SpawnActionContext;
 import com.google.devtools.build.lib.analysis.actions.CommandLine;
@@ -53,7 +55,7 @@ import javax.annotation.concurrent.GuardedBy;
 public final class ExtraAction extends SpawnAction {
   private final Action shadowedAction;
   private final boolean createDummyOutput;
-  private final ImmutableMap<PathFragment, Artifact> runfilesManifests;
+  private final RunfilesSupplier runfilesSupplier;
   private final ImmutableSet<Artifact> extraActionInputs;
   // This can be read/written from multiple threads, and so accesses should be synchronized.
   @GuardedBy("this")
@@ -71,9 +73,9 @@ public final class ExtraAction extends SpawnAction {
         }
       };
 
-  public ExtraAction(
+  ExtraAction(
       ImmutableSet<Artifact> extraActionInputs,
-      Map<PathFragment, Artifact> runfilesManifests,
+      RunfilesSupplier runfilesSupplier,
       Collection<Artifact> outputs,
       Action shadowedAction,
       boolean createDummyOutput,
@@ -86,7 +88,7 @@ public final class ExtraAction extends SpawnAction {
     super(
         shadowedAction.getOwner(),
         ImmutableList.<Artifact>of(),
-        createInputs(shadowedAction.getInputs(), extraActionInputs),
+        createInputs(shadowedAction.getInputs(), extraActionInputs, runfilesSupplier),
         outputs,
         AbstractAction.DEFAULT_RESOURCE_SET,
         argv,
@@ -94,12 +96,13 @@ public final class ExtraAction extends SpawnAction {
         ImmutableSet.copyOf(clientEnvironmentVariables),
         ImmutableMap.copyOf(executionInfo),
         progressMessage,
-        getManifests(shadowedAction),
+        // TODO(michajlo): Do we need the runfiles manifest as an input / should this be composite?
+        shadowedAction.getRunfilesSupplier(),
         mnemonic,
         false,
         null);
     this.shadowedAction = shadowedAction;
-    this.runfilesManifests = ImmutableMap.copyOf(runfilesManifests);
+    this.runfilesSupplier = runfilesSupplier;
     this.createDummyOutput = createDummyOutput;
 
     this.extraActionInputs = extraActionInputs;
@@ -110,16 +113,6 @@ public final class ExtraAction extends SpawnAction {
     }
   }
 
-  private static ImmutableMap<PathFragment, Artifact> getManifests(Action shadowedAction) {
-    // If the shadowed action is a SpawnAction, then we also add the input manifests to this
-    // action's input manifests.
-    // TODO(bazel-team): Also handle other action classes correctly.
-    if (shadowedAction instanceof SpawnAction) {
-      return ((SpawnAction) shadowedAction).getInputManifests();
-    }
-    return ImmutableMap.of();
-  }
-
   @Override
   public boolean discoversInputs() {
     return shadowedAction.discoversInputs();
@@ -135,7 +128,7 @@ public final class ExtraAction extends SpawnAction {
     if (shadowedAction.discoversInputs() && shadowedAction instanceof AbstractAction) {
       Iterable<Artifact> additionalInputs =
           ((AbstractAction) shadowedAction).getInputFilesForExtraAction(actionExecutionContext);
-      updateInputs(createInputs(additionalInputs, extraActionInputs));
+      updateInputs(createInputs(additionalInputs, extraActionInputs, runfilesSupplier));
       return ImmutableSet.copyOf(additionalInputs);
     }
     return null;
@@ -147,13 +140,16 @@ public final class ExtraAction extends SpawnAction {
   }
 
   private static NestedSet<Artifact> createInputs(
-      Iterable<Artifact> shadowedActionInputs, ImmutableSet<Artifact> extraActionInputs) {
+      Iterable<Artifact> shadowedActionInputs,
+      ImmutableSet<Artifact> extraActionInputs,
+      RunfilesSupplier extraActionRunfilesSupplier) {
     NestedSetBuilder<Artifact> result = new NestedSetBuilder<>(Order.STABLE_ORDER);
     if (shadowedActionInputs instanceof NestedSet) {
       result.addTransitive((NestedSet<Artifact>) shadowedActionInputs);
     } else {
       result.addAll(shadowedActionInputs);
     }
+    result.addAll(extraActionRunfilesSupplier.getArtifacts());
     return result.addAll(extraActionInputs).build();
   }
 
@@ -221,11 +217,9 @@ public final class ExtraAction extends SpawnAction {
   public Spawn getSpawn(Map<String, String> clientEnv) {
     final Spawn base = super.getSpawn(clientEnv);
     return new DelegateSpawn(base) {
-      @Override public ImmutableMap<PathFragment, Artifact> getRunfilesManifests() {
-        ImmutableMap.Builder<PathFragment, Artifact> builder = ImmutableMap.builder();
-        builder.putAll(super.getRunfilesManifests());
-        builder.putAll(runfilesManifests);
-        return builder.build();
+      @Override
+      public RunfilesSupplier getRunfilesSupplier() {
+        return new CompositeRunfilesSupplier(super.getRunfilesSupplier(), runfilesSupplier);
       }
 
       @Override public String getMnemonic() { return ExtraAction.this.getMnemonic(); }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionFactory.java b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionFactory.java
index e1b3c11b99..ef7062303b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionFactory.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.rules.extra;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.CompositeRunfilesSupplier;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.ConfigurationMakeVariableContext;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
@@ -27,11 +28,9 @@ import com.google.devtools.build.lib.analysis.Runfiles;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.cmdline.Label;
-import com.google.devtools.build.lib.packages.RuleClass.ConfiguredTargetFactory.RuleErrorException;
 import com.google.devtools.build.lib.packages.TargetUtils;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
 import com.google.devtools.build.lib.syntax.Type;
-
 import java.util.List;
 
 /**
@@ -78,7 +77,7 @@ public final class ExtraActionFactory implements RuleConfiguredTargetFactory {
 
     ExtraActionSpec spec = new ExtraActionSpec(
         commandHelper.getResolvedTools(),
-        commandHelper.getRemoteRunfileManifestMap(),
+        new CompositeRunfilesSupplier(commandHelper.getToolsRunfilesSuppliers()),
         resolvedData,
         outputTemplates,
         command,
diff --git a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionSpec.java b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionSpec.java
index 748a7a5fc8..81f1a8683d 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionSpec.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/extra/ExtraActionSpec.java
@@ -20,6 +20,7 @@ import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.actions.Action;
 import com.google.devtools.build.lib.actions.ActionOwner;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
@@ -44,7 +45,7 @@ import java.util.Set;
 @Immutable
 public final class ExtraActionSpec implements TransitiveInfoProvider {
   private final ImmutableList<Artifact> resolvedTools;
-  private final ImmutableMap<PathFragment, Artifact> manifests;
+  private final RunfilesSupplier runfilesSupplier;
   private final ImmutableList<Artifact> resolvedData;
   private final ImmutableList<String> outputTemplates;
   private final ImmutableMap<String, String> executionInfo;
@@ -54,7 +55,7 @@ public final class ExtraActionSpec implements TransitiveInfoProvider {
 
   ExtraActionSpec(
       Iterable<Artifact> resolvedTools,
-      Map<PathFragment, Artifact> manifests,
+      RunfilesSupplier runfilesSupplier,
       Iterable<Artifact> resolvedData,
       Iterable<String> outputTemplates,
       String command,
@@ -62,7 +63,7 @@ public final class ExtraActionSpec implements TransitiveInfoProvider {
       Map<String, String> executionInfo,
       boolean requiresActionOutput) {
     this.resolvedTools = ImmutableList.copyOf(resolvedTools);
-    this.manifests = ImmutableMap.copyOf(manifests);
+    this.runfilesSupplier = runfilesSupplier;
     this.resolvedData = ImmutableList.copyOf(resolvedData);
     this.outputTemplates = ImmutableList.copyOf(outputTemplates);
     this.command = command;
@@ -138,7 +139,7 @@ public final class ExtraActionSpec implements TransitiveInfoProvider {
     owningRule.registerAction(
         new ExtraAction(
             ImmutableSet.copyOf(extraActionInputs.build()),
-            manifests,
+            runfilesSupplier,
             extraActionOutputs,
             actionToShadow,
             createDummyOutput,
diff --git a/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleAction.java b/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleAction.java
index d77b89452c..a45b382f49 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleAction.java
@@ -21,10 +21,10 @@ import com.google.devtools.build.lib.actions.ActionOwner;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.ExecException;
 import com.google.devtools.build.lib.actions.ResourceSet;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.analysis.actions.CommandLine;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.events.EventHandler;
-import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.List;
 
 /**
@@ -46,7 +46,7 @@ public class GenRuleAction extends SpawnAction {
       ImmutableMap<String, String> environment,
       ImmutableSet<String> clientEnvironmentVariables,
       ImmutableMap<String, String> executionInfo,
-      ImmutableMap<PathFragment, Artifact> runfilesManifests,
+     RunfilesSupplier runfilesSupplier,
       String progressMessage) {
     super(
         owner,
@@ -59,7 +59,7 @@ public class GenRuleAction extends SpawnAction {
         clientEnvironmentVariables,
         executionInfo,
         progressMessage,
-        runfilesManifests,
+        runfilesSupplier,
         "Genrule",
         false,
         null);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java b/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java
index c990b15561..932d58040e 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/genrule/GenRuleBase.java
@@ -20,6 +20,7 @@ import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Maps;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.CompositeRunfilesSupplier;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.ConfigurationMakeVariableContext;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
@@ -190,7 +191,7 @@ public abstract class GenRuleBase implements RuleConfiguredTargetFactory {
             env,
             clientEnvVars,
             ImmutableMap.copyOf(executionInfo),
-            ImmutableMap.copyOf(commandHelper.getRemoteRunfileManifestMap()),
+            new CompositeRunfilesSupplier(commandHelper.getToolsRunfilesSuppliers()),
             message + ' ' + ruleContext.getLabel()));
 
     RunfilesProvider runfilesProvider = RunfilesProvider.withData(
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java
index faad216147..4eb7a6927e 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java
@@ -31,6 +31,7 @@ import com.google.devtools.build.lib.actions.Executor;
 import com.google.devtools.build.lib.actions.PackageRootResolutionException;
 import com.google.devtools.build.lib.actions.PackageRootResolver;
 import com.google.devtools.build.lib.actions.ResourceSet;
+import com.google.devtools.build.lib.actions.RunfilesSupplier;
 import com.google.devtools.build.lib.actions.Spawn;
 import com.google.devtools.build.lib.analysis.actions.CommandLine;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
@@ -74,7 +75,7 @@ public class ObjcCompileAction extends SpawnAction {
    * re-introduced into action inputs.
    */
   public class ObjcCompileActionSpawn extends ActionSpawn {
-    
+
     public ObjcCompileActionSpawn(Map<String, String> clientEnv) {
       super(clientEnv);
     }
@@ -84,10 +85,10 @@ public class ObjcCompileAction extends SpawnAction {
       return ImmutableList.<ActionInput>builder()
           .addAll(super.getInputFiles())
           .addAll(filterHeaderFiles())
-          .build();      
+          .build();
     }
   }
-  
+
   private final DotdFile dotdFile;
   private final Artifact sourceFile;
   private final NestedSet<Artifact> mandatoryInputs;
@@ -97,7 +98,7 @@ public class ObjcCompileAction extends SpawnAction {
   // This can be read/written from multiple threads, so accesses must be synchronized.
   @GuardedBy("this")
   private boolean inputsKnown = false;
-  
+
   private static final String GUID = "a00d5bac-a72c-4f0f-99a7-d5fdc6072137";
 
   private ObjcCompileAction(
@@ -110,7 +111,7 @@ public class ObjcCompileAction extends SpawnAction {
       ImmutableMap<String, String> environment,
       ImmutableMap<String, String> executionInfo,
       String progressMessage,
-      ImmutableMap<PathFragment, Artifact> inputManifests,
+      RunfilesSupplier runfilesSupplier,
       String mnemonic,
       boolean executeUnconditionally,
       ExtraActionInfoSupplier<?> extraActionInfoSupplier,
@@ -130,7 +131,7 @@ public class ObjcCompileAction extends SpawnAction {
         ImmutableSet.<String>of(),
         executionInfo,
         progressMessage,
-        inputManifests,
+        runfilesSupplier,
         mnemonic,
         executeUnconditionally,
         extraActionInfoSupplier);
@@ -151,7 +152,7 @@ public class ObjcCompileAction extends SpawnAction {
           inputs.add(headerArtifact);
         }
     }
-    return inputs.build();    
+    return inputs.build();
   }
 
   /** Returns the DotdPruningPlan for this compile */
@@ -164,12 +165,12 @@ public class ObjcCompileAction extends SpawnAction {
   public synchronized boolean inputsKnown() {
     return inputsKnown;
   }
-  
+
   @Override
   public final Spawn getSpawn(Map<String, String> clientEnv) {
     return new ObjcCompileActionSpawn(clientEnv);
   }
-  
+
   @Override
   public boolean discoversInputs() {
     return true;
@@ -184,7 +185,7 @@ public class ObjcCompileAction extends SpawnAction {
   public Iterable<Artifact> getInputsWhenSkippingInputDiscovery() {
     return filterHeaderFiles();
   }
- 
+
   // Keep in sync with {@link CppCompileAction#resolveInputsFromCache}
   @Override
   public Iterable<Artifact> resolveInputsFromCache(
@@ -225,17 +226,17 @@ public class ObjcCompileAction extends SpawnAction {
         inputs.add(artifact);
       }
     }
-    return inputs;    
+    return inputs;
   }
-  
+
   @Override
   public synchronized void updateInputs(Iterable<Artifact> inputs) {
     inputsKnown = true;
     synchronized (this) {
       setInputs(inputs);
     }
-  }  
-  
+  }
+
   @Override
   public ImmutableSet<Artifact> getMandatoryOutputs() {
     return ImmutableSet.of(dotdFile.artifact());
@@ -408,7 +409,7 @@ public class ObjcCompileAction extends SpawnAction {
       this.dotdPruningPlan = dotdPruningPlan;
       return this;
     }
-    
+
     /** Adds to the set of all possible headers that could be required by this compile action. */
     public Builder addTransitiveHeaders(NestedSet<Artifact> headers) {
       this.headers.addTransitive(Preconditions.checkNotNull(headers));
@@ -435,7 +436,7 @@ public class ObjcCompileAction extends SpawnAction {
         ImmutableSet<String> clientEnvironmentVariables,
         ImmutableMap<String, String> executionInfo,
         String progressMessage,
-        ImmutableMap<PathFragment, Artifact> inputAndToolManifests,
+        RunfilesSupplier runfilesSupplier,
         String mnemonic) {
       return new ObjcCompileAction(
           owner,
@@ -447,7 +448,7 @@ public class ObjcCompileAction extends SpawnAction {
           env,
           executionInfo,
           progressMessage,
-          inputAndToolManifests,
+          runfilesSupplier,
           mnemonic,
           executeUnconditionally,
           extraActionInfoSupplier,
diff --git a/src/main/java/com/google/devtools/build/lib/sandbox/DarwinSandboxedStrategy.java b/src/main/java/com/google/devtools/build/lib/sandbox/DarwinSandboxedStrategy.java
index ecffd79e4a..44a05f055c 100644
--- a/src/main/java/com/google/devtools/build/lib/sandbox/DarwinSandboxedStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/sandbox/DarwinSandboxedStrategy.java
@@ -282,7 +282,6 @@ public class DarwinSandboxedStrategy extends SandboxStrategy {
       spawnHelpers.mountInputs(mounts, spawn, executionContext);
 
       Map<PathFragment, Path> unfinalized = new HashMap<>();
-      spawnHelpers.mountRunfilesFromManifests(unfinalized, spawn);
       spawnHelpers.mountRunfilesFromSuppliers(unfinalized, spawn);
       spawnHelpers.mountFilesFromFilesetManifests(unfinalized, spawn, executionContext);
       mounts.putAll(finalizeLinks(unfinalized));
diff --git a/src/main/java/com/google/devtools/build/lib/sandbox/SpawnHelpers.java b/src/main/java/com/google/devtools/build/lib/sandbox/SpawnHelpers.java
index b5b920cc31..8e3c26f93d 100644
--- a/src/main/java/com/google/devtools/build/lib/sandbox/SpawnHelpers.java
+++ b/src/main/java/com/google/devtools/build/lib/sandbox/SpawnHelpers.java
@@ -52,25 +52,12 @@ public final class SpawnHelpers {
   public Map<PathFragment, Path> getMounts(Spawn spawn, ActionExecutionContext executionContext)
       throws IOException {
     Map<PathFragment, Path> mounts = new HashMap<>();
-    mountRunfilesFromManifests(mounts, spawn);
     mountRunfilesFromSuppliers(mounts, spawn);
     mountFilesFromFilesetManifests(mounts, spawn, executionContext);
     mountInputs(mounts, spawn, executionContext);
     return mounts;
   }
 
-  /** Mount all runfiles that the spawn needs as specified in its runfiles manifests. */
-  void mountRunfilesFromManifests(Map<PathFragment, Path> mounts, Spawn spawn) throws IOException {
-    for (Map.Entry<PathFragment, Artifact> manifest : spawn.getRunfilesManifests().entrySet()) {
-      String manifestFilePath = manifest.getValue().getPath().getPathString();
-      Preconditions.checkState(!manifest.getKey().isAbsolute());
-      PathFragment targetDirectory = manifest.getKey();
-
-      parseManifestFile(
-          execRoot.getFileSystem(), mounts, targetDirectory, new File(manifestFilePath), false, "");
-    }
-  }
-
   /** Mount all files that the spawn needs as specified in its fileset manifests. */
   void mountFilesFromFilesetManifests(
       Map<PathFragment, Path> mounts, Spawn spawn, ActionExecutionContext executionContext)