Move FDO support to the analysis phase by wrapping FdoSupport in its own SkyFunction.

This removes one of the two reasons for the existence of BuildConfiguration#prepareToBuild() which makes implementing dynamic configurations impossible and also makes FDO support halfway sane; now FDO is exactly as ugly as remote repositories, that is to say, reasonably okay.

Ideally, we'd implement the zip extraction as an Action and make it a TreeArtifact, but support for TreeArtifacts is not mature yet enough, so it's not possible at the moment.

--
MOS_MIGRATED_REVID=119150223

17 files changed, 473 insertions, 236 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java b/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java
index 7a4f72a4f7..98a57b81ca 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/BuildView.java
@@ -403,13 +403,6 @@ public class BuildView {
         });
   }
 
-  private void prepareToBuild(BuildConfigurationCollection configurations)
-      throws ViewCreationFailedException {
-    for (BuildConfiguration config : configurations.getAllConfigurations()) {
-      config.prepareToBuild(directories.getExecRoot());
-    }
-  }
-
   @ThreadCompatible
   public AnalysisResult update(
       LoadingResult loadingResult,
@@ -484,7 +477,6 @@ public class BuildView {
       }
     }
 
-    prepareToBuild(configurations);
     skyframeExecutor.injectWorkspaceStatusData();
     SkyframeAnalysisResult skyframeAnalysisResult;
     try {
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
index e0ced04c8d..33aa510f7a 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
@@ -34,7 +34,6 @@ import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.Dependency;
 import com.google.devtools.build.lib.analysis.RuleContext;
-import com.google.devtools.build.lib.analysis.ViewCreationFailedException;
 import com.google.devtools.build.lib.analysis.config.BuildConfigurationCollection.Transitions;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
@@ -169,18 +168,6 @@ public final class BuildConfiguration {
     }
 
     /**
-     * The fragment may use this hook to perform I/O and read data into memory that is used during
-     * analysis. During the analysis phase disk I/O operations are disallowed.
-     *
-     * <p>This hook is called for all configurations after the loading phase is complete.
-     *
-     * <p>Do not use this method to change your fragment's state.
-     */
-    @SuppressWarnings("unused")
-    public void prepareHook(Path execPath) throws ViewCreationFailedException {
-    }
-
-    /**
      * Adds all the roots from this fragment.
      */
     @SuppressWarnings("unused")
@@ -2332,21 +2319,6 @@ public final class BuildConfiguration {
   }
 
   /**
-   * Prepare the fdo support. It reads data into memory that is used during analysis. The analysis
-   * phase is generally not allowed to perform disk I/O. This code is here because it is
-   * conceptually part of the analysis phase, and it needs to happen when the loading phase is
-   * complete.
-   *
-   * <p>C++ also requires this to resolve artifacts that are unconditionally included in every
-   * compilation.</p>
-   */
-  public void prepareToBuild(Path execRoot) throws ViewCreationFailedException {
-    for (Fragment fragment : fragments.values()) {
-      fragment.prepareHook(execRoot);
-    }
-  }
-
-  /**
    * Declares dependencies on any relevant Skyframe values (for example, relevant FileValues).
    */
   public void declareSkyframeDependencies(SkyFunction.Environment env) {
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java
index 2af2575ff9..a0c142e096 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java
@@ -24,6 +24,7 @@ import com.google.devtools.build.lib.actions.ActionContextConsumer;
 import com.google.devtools.build.lib.actions.ActionContextProvider;
 import com.google.devtools.build.lib.actions.Executor.ActionContext;
 import com.google.devtools.build.lib.actions.SimpleActionContextProvider;
+import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.actions.FileWriteActionContext;
 import com.google.devtools.build.lib.bazel.rules.cpp.BazelCppRuleClasses;
@@ -31,6 +32,8 @@ import com.google.devtools.build.lib.query2.output.OutputFormatter;
 import com.google.devtools.build.lib.rules.android.WriteAdbArgsActionContext;
 import com.google.devtools.build.lib.rules.cpp.CppCompileActionContext;
 import com.google.devtools.build.lib.rules.cpp.CppLinkActionContext;
+import com.google.devtools.build.lib.rules.cpp.FdoSupportFunction;
+import com.google.devtools.build.lib.rules.cpp.FdoSupportValue;
 import com.google.devtools.build.lib.rules.cpp.IncludeScanningContext;
 import com.google.devtools.build.lib.rules.genquery.GenQuery;
 import com.google.devtools.build.lib.runtime.BlazeModule;
@@ -39,6 +42,8 @@ import com.google.devtools.build.lib.runtime.CommandEnvironment;
 import com.google.devtools.build.lib.runtime.GotOptionsEvent;
 import com.google.devtools.build.lib.skyframe.PrecomputedValue;
 import com.google.devtools.build.lib.util.ResourceFileLoader;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionName;
 import com.google.devtools.common.options.Converters.AssignmentConverter;
 import com.google.devtools.common.options.Option;
 import com.google.devtools.common.options.OptionsBase;
@@ -194,4 +199,10 @@ public class BazelRulesModule extends BlazeModule {
           }
         }));
   }
+
+  @Override
+  public ImmutableMap<SkyFunctionName, SkyFunction> getSkyFunctions(BlazeDirectories directories) {
+    return ImmutableMap.<SkyFunctionName, SkyFunction>of(
+        FdoSupportValue.SKYFUNCTION, new FdoSupportFunction());
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
index 579bb53bfa..b1639ea9a2 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
@@ -178,7 +178,7 @@ public final class CcCommon {
   }
 
   public TransitiveLipoInfoProvider collectTransitiveLipoLabels(CcCompilationOutputs outputs) {
-    if (cppConfiguration.getFdoSupport().getFdoRoot() == null
+    if (CppHelper.getFdoSupport(ruleContext).getFdoRoot() == null
         || !cppConfiguration.isLipoContextCollector()) {
       return TransitiveLipoInfoProvider.EMPTY;
     }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java
index 79d1c8d2dd..1ec2c57387 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcLibraryHelper.java
@@ -922,7 +922,7 @@ public final class CcLibraryHelper {
   }
 
   private TransitiveLipoInfoProvider collectTransitiveLipoInfo(CcCompilationOutputs outputs) {
-    if (ruleContext.getFragment(CppConfiguration.class).getFdoSupport().getFdoRoot() == null) {
+    if (CppHelper.getFdoSupport(ruleContext).getFdoRoot() == null) {
       return TransitiveLipoInfoProvider.EMPTY;
     }
     NestedSetBuilder<IncludeScannable> scannableBuilder = NestedSetBuilder.stableOrder();
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
index 6cc3a5c401..e3efe6c0ce 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
@@ -33,15 +33,21 @@ import com.google.devtools.build.lib.analysis.RuleContext;
 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.analysis.config.CompilationMode;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.packages.License;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.rules.cpp.FdoSupport.FdoException;
 import com.google.devtools.build.lib.util.Preconditions;
+import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyKey;
 
+import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 
@@ -57,6 +63,29 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
 
   @Override
   public ConfiguredTarget create(RuleContext ruleContext) {
+    CppConfiguration cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
+    Path fdoZip = ruleContext.getConfiguration().getCompilationMode() == CompilationMode.OPT
+        ? cppConfiguration.getFdoZip()
+        : null;
+    SkyKey fdoKey = FdoSupportValue.key(
+        cppConfiguration.getLipoMode(),
+        fdoZip,
+        cppConfiguration.getFdoInstrument());
+
+    SkyFunction.Environment skyframeEnv = ruleContext.getAnalysisEnvironment().getSkyframeEnv();
+    FdoSupportValue fdoSupport;
+    try {
+      fdoSupport = (FdoSupportValue) skyframeEnv.getValueOrThrow(
+          fdoKey, FdoException.class, IOException.class);
+    } catch (FdoException | IOException e) {
+      ruleContext.ruleError("cannot initialize FDO: " + e.getMessage());
+      return null;
+    }
+
+    if (skyframeEnv.valuesMissing()) {
+      return null;
+    }
+
     final Label label = ruleContext.getLabel();
     final NestedSet<Artifact> crosstool = ruleContext.getPrerequisite("all_files", Mode.HOST)
         .getProvider(FileProvider.class).getFilesToBuild();
@@ -72,7 +101,6 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
     final PathFragment runtimeSolibDir = ruleContext.getConfiguration()
         .getBinFragment().getRelative(runtimeSolibDirBase);
 
-    CppConfiguration cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
     // Static runtime inputs.
     TransitiveInfoCollection staticRuntimeLibDep = selectDep(ruleContext, "static_runtime_libs",
         cppConfiguration.getStaticRuntimeLibsLabel());
@@ -173,6 +201,7 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
     RuleConfiguredTargetBuilder builder =
         new RuleConfiguredTargetBuilder(ruleContext)
             .add(CcToolchainProvider.class, provider)
+            .add(FdoSupportProvider.class, new FdoSupportProvider(fdoSupport.getFdoSupport()))
             .setFilesToBuild(new NestedSetBuilder<Artifact>(Order.STABLE_ORDER).build())
             .add(RunfilesProvider.class, RunfilesProvider.simple(Runfiles.EMPTY));
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index f151deaf59..c1831ceaf7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -25,9 +25,7 @@ import com.google.common.collect.Iterables;
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Multimap;
-import com.google.devtools.build.lib.actions.Root;
 import com.google.devtools.build.lib.analysis.RuleContext;
-import com.google.devtools.build.lib.analysis.ViewCreationFailedException;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
 import com.google.devtools.build.lib.analysis.config.CompilationMode;
@@ -40,7 +38,6 @@ import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.rules.cpp.CppConfigurationLoader.CppConfigurationParameters;
-import com.google.devtools.build.lib.rules.cpp.FdoSupport.FdoException;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.util.Preconditions;
@@ -51,7 +48,6 @@ import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig;
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.CToolchain;
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.LinkingModeFlags;
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.LipoMode;
-import com.google.devtools.build.skyframe.SkyFunction.Environment;
 import com.google.devtools.common.options.OptionsParsingException;
 import com.google.protobuf.TextFormat;
 import com.google.protobuf.TextFormat.ParseException;
@@ -64,7 +60,6 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.zip.ZipException;
 
 /**
  * This class represents the C/C++ parts of the {@link BuildConfiguration},
@@ -284,7 +279,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   private final boolean toolchainNeedsPic;
   private final boolean usePicForBinaries;
 
-  private final FdoSupport fdoSupport;
+  private final Path fdoZip;
 
   // TODO(bazel-team): All these labels (except for ccCompilerRuleLabel) can be removed once the
   // transition to the cc_compiler rule is complete.
@@ -390,10 +385,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
       }
     }
 
-    this.fdoSupport = new FdoSupport(
-        cppOptions.fdoInstrument, params.fdoZip,
-        cppOptions.lipoMode, execRoot);
-
+    this.fdoZip = params.fdoZip;
     this.stripBinaries =
         (cppOptions.stripBinaries == StripMode.ALWAYS
             || (cppOptions.stripBinaries == StripMode.SOMETIMES
@@ -1481,8 +1473,9 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
    * Returns true if it is AutoFDO LIPO build.
    */
   public boolean isAutoFdoLipo() {
-    return cppOptions.fdoOptimize != null && FdoSupport.isAutoFdo(cppOptions.fdoOptimize)
-           && getLipoMode() != LipoMode.OFF;
+    return cppOptions.fdoOptimize != null
+        && CppFileTypes.GCC_AUTO_PROFILE.matches(cppOptions.fdoOptimize)
+        && getLipoMode() != LipoMode.OFF;
   }
 
   /**
@@ -1639,13 +1632,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   /**
-   * Returns the FDO support object.
-   */
-  public FdoSupport getFdoSupport() {
-    return fdoSupport;
-  }
-
-  /**
    * Return the name of the directory (relative to the bin directory) that
    * holds mangled links to shared libraries. This name is always set to
    * the '{@code _solib_<cpu_archictecture_name>}.
@@ -1892,35 +1878,10 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   @Override
-  public void prepareHook(Path execRoot) throws ViewCreationFailedException {
-    try {
-      getFdoSupport().prepareToBuild(execRoot);
-    } catch (ZipException e) {
-      throw new ViewCreationFailedException("Error reading provided FDO zip file", e);
-    } catch (FdoException | IOException e) {
-      throw new ViewCreationFailedException("Error while initializing FDO support", e);
-    }
-  }
-
-  @Override
-  public void declareSkyframeDependencies(Environment env) {
-    getFdoSupport().declareSkyframeDependencies(env, execRoot);
-  }
-
-  @Override
-  public void addRoots(List<Root> roots) {
-    // Fdo root can only exist for the target configuration.
-    FdoSupport fdoSupport = getFdoSupport();
-    if (fdoSupport.getFdoRoot() != null) {
-      roots.add(fdoSupport.getFdoRoot());
-    }
-  }
-
-  @Override
   public Map<String, String> getCoverageEnvironment() {
     ImmutableMap.Builder<String, String> env = ImmutableMap.builder();
     env.put("COVERAGE_GCOV_PATH", getGcovExecutable().getPathString());
-    PathFragment fdoInstrument = getFdoSupport().getFdoInstrument();
+    PathFragment fdoInstrument = cppOptions.fdoInstrument;
     if (fdoInstrument != null) {
       env.put("FDO_DIR", fdoInstrument.getPathString());
     }
@@ -1990,6 +1951,14 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     );
   }
 
+  public PathFragment getFdoInstrument() {
+    return cppOptions.fdoInstrument;
+  }
+
+  public Path getFdoZip() {
+    return fdoZip;
+  }
+
   /**
    * Return set of features enabled by the CppConfiguration, specifically
    * the FDO and LIPO related features enabled by options.
@@ -1997,15 +1966,15 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   @Override
   public ImmutableSet<String> configurationEnabledFeatures(RuleContext ruleContext) {
     ImmutableSet.Builder<String> requestedFeatures = ImmutableSet.builder();
-    FdoSupport fdoSupport = getFdoSupport();
-    if (fdoSupport.getFdoInstrument() != null) {
+    if (cppOptions.fdoInstrument != null) {
       requestedFeatures.add(CppRuleClasses.FDO_INSTRUMENT);
     }
-    if (fdoSupport.getFdoOptimizeProfile() != null
-        && !fdoSupport.isAutoFdoEnabled()) {
+
+    boolean isFdo = fdoZip != null && compilationMode == CompilationMode.OPT;
+    if (isFdo && !CppFileTypes.GCC_AUTO_PROFILE.matches(fdoZip)) {
       requestedFeatures.add(CppRuleClasses.FDO_OPTIMIZE);
     }
-    if (fdoSupport.isAutoFdoEnabled()) {
+    if (isFdo && CppFileTypes.GCC_AUTO_PROFILE.matches(fdoZip)) {
       requestedFeatures.add(CppRuleClasses.AUTOFDO);
     }
     if (isLipoOptimizationOrInstrumentation()) {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
index 97db3a514f..300c87e122 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
@@ -214,6 +214,13 @@ public class CppHelper {
     return false;
   }
 
+  @Nullable public static FdoSupport getFdoSupport(RuleContext ruleContext) {
+    return ruleContext
+        .getPrerequisite(":cc_toolchain", Mode.TARGET)
+        .getProvider(FdoSupportProvider.class)
+        .getFdoSupport();
+  }
+
   /**
    * This almost trivial method looks up the :cc_toolchain attribute on the rule context, makes sure
    * that it refers to a rule that has a {@link CcToolchainProvider} (gives an error otherwise), and
@@ -508,8 +515,9 @@ public class CppHelper {
   /**
    * Returns the FDO build subtype.
    */
-  public static String getFdoBuildStamp(CppConfiguration cppConfiguration) {
-    if (cppConfiguration.getFdoSupport().isAutoFdoEnabled()) {
+  public static String getFdoBuildStamp(RuleContext ruleContext) {
+    CppConfiguration cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
+    if (getFdoSupport(ruleContext).isAutoFdoEnabled()) {
       return (cppConfiguration.getLipoMode() == LipoMode.BINARY) ? "ALIPO" : "AFDO";
     }
     if (cppConfiguration.isFdo()) {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkAction.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkAction.java
index 95d6379f18..b0a1b7d825 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkAction.java
@@ -1213,24 +1213,6 @@ public final class CppLinkAction extends AbstractAction {
       this.runtimeSolibDir = runtimeSolibDir;
       return this;
     }
-
-    /**
-     * Creates a builder without the need for a {@link RuleContext}.
-     * This is to be used exclusively for testing purposes.
-     *
-     * <p>Link stamping is not supported if using this method.
-     */
-    @VisibleForTesting
-    public static Builder createTestBuilder(
-        final ActionOwner owner, final AnalysisEnvironment analysisEnvironment,
-        final Artifact output, BuildConfiguration config) {
-      return new Builder(null, output, config, analysisEnvironment, null) {
-        @Override
-        protected ActionOwner getOwner() {
-          return owner;
-        }
-      };
-    }
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java
index c8a8c1a19b..bd8bbfa1a2 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppModel.java
@@ -287,7 +287,7 @@ public final class CppModel {
     }
 
     builder.setExtraSystemIncludePrefixes(additionalIncludes);
-    builder.setFdoBuildStamp(CppHelper.getFdoBuildStamp(cppConfiguration));
+    builder.setFdoBuildStamp(CppHelper.getFdoBuildStamp(ruleContext));
     builder.setFeatureConfiguration(featureConfiguration);
     return builder;
   }
@@ -367,8 +367,8 @@ public final class CppModel {
     }
 
     if (ccRelativeName != null) {
-      cppConfiguration.getFdoSupport().configureCompilation(builder, buildVariables, ruleContext,
-          ccRelativeName, autoFdoImportPath, usePic, featureConfiguration);
+      CppHelper.getFdoSupport(ruleContext).configureCompilation(builder, buildVariables,
+          ruleContext, ccRelativeName, autoFdoImportPath, usePic, featureConfiguration);
     }
     if (gcnoFile != null) {
       buildVariables.addVariable("gcov_gcno_file", gcnoFile.getExecPathString());
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java
index b182c8cf04..18f2cf18df 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupport.java
@@ -25,7 +25,7 @@ import com.google.devtools.build.lib.actions.Root;
 import com.google.devtools.build.lib.analysis.AnalysisEnvironment;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.cmdline.Label;
-import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadHostile;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
 import com.google.devtools.build.lib.rules.cpp.CcToolchainFeatures.FeatureConfiguration;
 import com.google.devtools.build.lib.skyframe.FileValue;
@@ -47,20 +47,13 @@ import java.util.zip.ZipException;
  * Support class for FDO (feedback directed optimization) and LIPO (lightweight inter-procedural
  * optimization).
  *
- * <p>There is a 1:1 relationship between {@link CppConfiguration} objects and {@code FdoSupport}
- * objects. The FDO support of a build configuration can be retrieved using {@link
- * CppConfiguration#getFdoSupport()}.
- *
- * <p>With respect to thread-safety, the {@link #prepareToBuild} method is not thread-safe, and must
- * not be called concurrently with other methods on this class.
- *
  * <p>Here follows a quick run-down of how FDO/LIPO builds work (for non-FDO/LIPO builds, none
  * of this applies):
  *
- * <p>{@link CppConfiguration#prepareHook} is called before the analysis phase, which calls
- * {@link #prepareToBuild}, which extracts the FDO .zip (in case we work with an explicitly
- * generated FDO profile file) or analyzes the .afdo.imports file next to the .afdo file (if
- * AutoFDO is in effect).
+ * <p>{@link FdoSupport#create} is called from {@link FdoSupportFunction} (a {@link SkyFunction}),
+ * which is requested from Skyframe by the {@code cc_toolchain} rule. It extracts the FDO .zip (in
+ * case we work with an explicitly generated FDO profile file) or analyzes the .afdo.imports file
+ * next to the .afdo file (if AutoFDO is in effect).
  *
  * <p>.afdo.imports files contain one import a line. A line is two paths separated by a colon,
  * with functions in the second path being referenced by functions in the first path. These are
@@ -108,9 +101,30 @@ import java.util.zip.ZipException;
  * {@code CachingAnalysisEnvironment.allowRegisteringActions}, which causes actions to be silently
  * discarded after configured targets are created.
  */
+@Immutable
 public class FdoSupport {
 
   /**
+   * The FDO mode we are operating in.
+   *
+   * LIPO can only be active if this is not <code>OFF</code>, but all of the modes below can work
+   * with LIPO either off or on.
+   */
+  private enum FdoMode {
+    /** FDO is turned off. */
+    OFF,
+
+    /** Profiling-based FDO using an explicitly recorded profile. */
+    VANILLA,
+
+    /** FDO based on automatically collected data. */
+    AUTO_FDO,
+
+    /** Instrumentation-based FDO implemented on LLVM. */
+    LLVM_FDO,
+  }
+
+  /**
    * Path within profile data .zip files that is considered the root of the
    * profile information directory tree.
    */
@@ -170,24 +184,15 @@ public class FdoSupport {
   private final LipoMode lipoMode;
 
   /**
-   * Flag indicating whether to use AutoFDO (as opposed to
-   * instrumentation-based FDO).
+   * FDO mode.
    */
-  private final boolean useAutoFdo;
-
-  /**
-   * Flag indicating whether to use LLVM instrumentation-based FDO (as
-   * opposed to GCC instrumentation-based FDO).
-   */
-  private final boolean useLLVMFdo;
+  private final FdoMode fdoMode;
 
   /**
    * The {@code .gcda} files that have been extracted from the ZIP file,
    * relative to the root of the ZIP file.
-   *
-   * <p>Set only in {@link #prepareToBuild}.
    */
-  private ImmutableSet<PathFragment> gcdaFiles = ImmutableSet.of();
+  private final ImmutableSet<PathFragment> gcdaFiles;
 
   /**
    * Multimap from .gcda file base names to auxiliary input files.
@@ -198,10 +203,8 @@ public class FdoSupport {
    *
    * <p>The contents of the multimap are copied verbatim from the .gcda.imports
    * files and not yet checked for validity.
-   *
-   * <p>Set only in {@link #prepareToBuild}.
    */
-  private ImmutableMultimap<PathFragment, PathFragment> imports;
+  private final ImmutableMultimap<PathFragment, PathFragment> imports;
 
   /**
    * Creates an FDO support object.
@@ -210,83 +213,122 @@ public class FdoSupport {
    * @param fdoProfile path to the profile file passed to --fdo_optimize option
    * @param lipoMode value of the --lipo_mode option
    */
-  public FdoSupport(PathFragment fdoInstrument, Path fdoProfile, LipoMode lipoMode, Path execRoot) {
+  private FdoSupport(FdoMode fdoMode, LipoMode lipoMode, Root fdoRoot, PathFragment fdoRootExecPath,
+      PathFragment fdoInstrument, Path fdoProfile, FdoZipContents fdoZipContents) {
     this.fdoInstrument = fdoInstrument;
     this.fdoProfile = fdoProfile;
-    this.fdoRoot = (fdoProfile == null)
-        ? null
-        : Root.asDerivedRoot(execRoot, execRoot.getRelative("blaze-fdo"));
-    this.fdoRootExecPath = fdoProfile == null
-        ? null
-        : fdoRoot.getExecPath().getRelative(FileSystemUtils.removeExtension(
-            new PathFragment("_fdo").getChild(fdoProfile.getBaseName())));
+    this.fdoRoot = fdoRoot;
+    this.fdoRootExecPath = fdoRootExecPath;
     this.fdoPath = fdoProfile == null
         ? null
         : FileSystemUtils.removeExtension(new PathFragment("_fdo").getChild(
             fdoProfile.getBaseName()));
     this.lipoMode = lipoMode;
-    this.useAutoFdo = fdoProfile != null && isAutoFdo(fdoProfile.getBaseName());
-    this.useLLVMFdo = fdoProfile != null && isLLVMFdo(fdoProfile.getBaseName());
+    this.fdoMode = fdoMode;
+    this.gcdaFiles = fdoZipContents.gcdaFiles;
+    this.imports = fdoZipContents.imports;
   }
 
   public Root getFdoRoot() {
     return fdoRoot;
   }
 
-  public void declareSkyframeDependencies(SkyFunction.Environment env, Path execRoot) {
+  /**
+   * Creates an initialized {@link FdoSupport} instance.
+   */
+  static FdoSupport create(SkyFunction.Environment env, PathFragment fdoInstrument,
+      Path fdoProfile, LipoMode lipoMode, Path execRoot) throws IOException, FdoException {
+    FdoMode fdoMode;
+    if (fdoProfile != null && isAutoFdo(fdoProfile.getBaseName())) {
+      fdoMode = FdoMode.AUTO_FDO;
+    } else if (fdoProfile != null && isLLVMFdo(fdoProfile.getBaseName())) {
+      fdoMode = FdoMode.LLVM_FDO;
+    } else if (fdoProfile != null) {
+      fdoMode = FdoMode.VANILLA;
+    } else {
+      fdoMode = FdoMode.OFF;
+    }
+
+    if (fdoProfile == null) {
+      lipoMode = LipoMode.OFF;
+    }
+
+    Root fdoRoot = (fdoProfile == null)
+        ? null
+        : Root.asDerivedRoot(execRoot, execRoot.getRelative("blaze-fdo"));
+
+    PathFragment fdoRootExecPath = fdoProfile == null
+        ? null
+        : fdoRoot.getExecPath().getRelative(FileSystemUtils.removeExtension(
+            new PathFragment("_fdo").getChild(fdoProfile.getBaseName())));
+
     if (fdoProfile != null) {
-      if (isLipoEnabled()) {
+      if (lipoMode != LipoMode.OFF) {
         // Incrementality is not supported for LIPO builds, see FdoSupport#scannables.
         // Ensure that the Skyframe value containing the configuration will not be reused to avoid
         // incrementality issues.
         PrecomputedValue.dependOnBuildId(env);
-        return;
-      }
-
-      // IMPORTANT: Keep the following in sync with #prepareToBuild.
-      Path path;
-      if (useAutoFdo) {
-        path = fdoProfile.getParentDirectory().getRelative(
-            fdoProfile.getBaseName() + ".imports");
       } else {
-        path = fdoProfile;
+        Path path = fdoMode == FdoMode.AUTO_FDO ? getAutoFdoImportsPath(fdoProfile) : fdoProfile;
+        env.getValue(FileValue.key(RootedPath.toRootedPathMaybeUnderRoot(path,
+            ImmutableList.of(execRoot))));
       }
-      env.getValue(FileValue.key(RootedPath.toRootedPathMaybeUnderRoot(path,
-          ImmutableList.of(execRoot))));
+    }
+
+    if (env.valuesMissing()) {
+      return null;
+    }
+
+    FdoZipContents fdoZipContents = extractFdoZip(
+        fdoMode, lipoMode, execRoot, fdoProfile, fdoRootExecPath);
+    return new FdoSupport(
+        fdoMode, lipoMode, fdoRoot, fdoRootExecPath, fdoInstrument, fdoProfile, fdoZipContents);
+  }
+
+  @Immutable
+  private static class FdoZipContents {
+    private final ImmutableSet<PathFragment> gcdaFiles;
+    private final ImmutableMultimap<PathFragment, PathFragment> imports;
+
+    private FdoZipContents(ImmutableSet<PathFragment> gcdaFiles,
+        ImmutableMultimap<PathFragment, PathFragment> imports) {
+      this.gcdaFiles = gcdaFiles;
+      this.imports = imports;
     }
   }
 
   /**
-   * Prepares the FDO support for building.
+   * Extracts the FDO zip file and collects data from it that's needed during analysis.
    *
    * <p>When an {@code --fdo_optimize} compile is requested, unpacks the given
    * FDO gcda zip file into a clean working directory under execRoot.
    *
    * @throws FdoException if the FDO ZIP contains a file of unknown type
    */
-  @ThreadHostile // must be called before starting the build
-  public void prepareToBuild(Path execRoot)
+  private static FdoZipContents extractFdoZip(FdoMode fdoMode, LipoMode lipoMode, Path execRoot,
+      Path fdoProfile, PathFragment fdoRootExecPath)
       throws IOException, FdoException {
     // The execRoot != null case is only there for testing. We cannot provide a real ZIP file in
     // tests because ZipFileSystem does not work with a ZIP on an in-memory file system.
     // IMPORTANT: Keep in sync with #declareSkyframeDependencies to avoid incrementality issues.
+    ImmutableSet<PathFragment> gcdaFiles = ImmutableSet.of();
+    ImmutableMultimap<PathFragment, PathFragment> imports = ImmutableMultimap.of();
+
     if (fdoProfile != null && execRoot != null) {
       Path fdoDirPath = execRoot.getRelative(fdoRootExecPath);
 
       FileSystemUtils.deleteTreesBelow(fdoDirPath);
       FileSystemUtils.createDirectoryAndParents(fdoDirPath);
 
-      if (useAutoFdo) {
-        Path fdoImports = fdoProfile.getParentDirectory().getRelative(
-            fdoProfile.getBaseName() + ".imports");
-        if (isLipoEnabled()) {
-          imports = readAutoFdoImports(fdoImports);
+      if (fdoMode == FdoMode.AUTO_FDO) {
+        if (lipoMode != LipoMode.OFF) {
+          imports = readAutoFdoImports(getAutoFdoImportsPath(fdoProfile));
         }
         FileSystemUtils.ensureSymbolicLink(
-            execRoot.getRelative(getAutoProfilePath()), fdoProfile);
-      } else if (useLLVMFdo) {
+            execRoot.getRelative(getAutoProfilePath(fdoProfile, fdoRootExecPath)), fdoProfile);
+      } else if (fdoMode == FdoMode.LLVM_FDO) {
         FileSystemUtils.ensureSymbolicLink(
-            execRoot.getRelative(getLLVMProfilePath()), fdoProfile);
+            execRoot.getRelative(getLLVMProfilePath(fdoProfile, fdoRootExecPath)), fdoProfile);
       } else {
         Path zipFilePath = new ZipFileSystem(fdoProfile).getRootDirectory();
         if (!zipFilePath.getRelative("blaze-out").isDirectory()) {
@@ -296,11 +338,13 @@ public class FdoSupport {
         ImmutableSet.Builder<PathFragment> gcdaFilesBuilder = ImmutableSet.builder();
         ImmutableMultimap.Builder<PathFragment, PathFragment> importsBuilder =
             ImmutableMultimap.builder();
-        extractFdoZip(zipFilePath, fdoDirPath, gcdaFilesBuilder, importsBuilder);
+        extractFdoZipDirectory(zipFilePath, fdoDirPath, gcdaFilesBuilder, importsBuilder);
         gcdaFiles = gcdaFilesBuilder.build();
         imports = importsBuilder.build();
       }
     }
+
+    return new FdoZipContents(gcdaFiles, imports);
   }
 
   /**
@@ -320,7 +364,7 @@ public class FdoSupport {
    * @throws IOException if any of the I/O operations failed
    * @throws FdoException if the FDO ZIP contains a file of unknown type
    */
-  private void extractFdoZip(Path sourceDir, Path targetDir,
+  private static void extractFdoZipDirectory(Path sourceDir, Path targetDir,
       ImmutableSet.Builder<PathFragment> gcdaFilesBuilder,
       ImmutableMultimap.Builder<PathFragment, PathFragment> importsBuilder)
           throws IOException, FdoException {
@@ -328,7 +372,7 @@ public class FdoSupport {
       Path targetFile = targetDir.getRelative(sourceFile.getBaseName());
       if (sourceFile.isDirectory()) {
         targetFile.createDirectory();
-        extractFdoZip(sourceFile, targetFile, gcdaFilesBuilder, importsBuilder);
+        extractFdoZipDirectory(sourceFile, targetFile, gcdaFilesBuilder, importsBuilder);
       } else {
         if (CppFileTypes.COVERAGE_DATA.matches(sourceFile)) {
           FileSystemUtils.copyFile(sourceFile, targetFile);
@@ -343,12 +387,13 @@ public class FdoSupport {
     }
   }
 
+
   /**
    * Reads a .gcda.imports file and stores the imports information.
    *
    * @throws FdoException if an auxiliary LIPO input was not found
    */
-  private void readCoverageImports(Path importsFile,
+  private static void readCoverageImports(Path importsFile,
       ImmutableMultimap.Builder<PathFragment, PathFragment> importsBuilder)
           throws IOException, FdoException {
     PathFragment key = importsFile.asFragment().relativeTo(ZIP_ROOT);
@@ -373,7 +418,7 @@ public class FdoSupport {
   /**
    * Reads a .afdo.imports file and stores the imports information.
    */
-  private ImmutableMultimap<PathFragment, PathFragment> readAutoFdoImports(Path importsFile)
+  private static ImmutableMultimap<PathFragment, PathFragment> readAutoFdoImports(Path importsFile)
           throws IOException, FdoException {
     ImmutableMultimap.Builder<PathFragment, PathFragment> importBuilder =
         ImmutableMultimap.builder();
@@ -396,6 +441,10 @@ public class FdoSupport {
     return importBuilder.build();
   }
 
+  private static Path getAutoFdoImportsPath(Path fdoProfile) {
+     return fdoProfile.getParentDirectory().getRelative(fdoProfile.getBaseName() + ".imports");
+  }
+
   /**
    * Returns the imports from the .afdo.imports file of a source file.
    *
@@ -403,7 +452,7 @@ public class FdoSupport {
    */
   private Collection<Artifact> getAutoFdoImports(RuleContext ruleContext,
       PathFragment sourceExecPath, LipoContextProvider lipoContextProvider) {
-    Preconditions.checkState(isLipoEnabled());
+    Preconditions.checkState(lipoMode != LipoMode.OFF);
     ImmutableCollection<PathFragment> afdoImports = imports.get(sourceExecPath);
     Preconditions.checkState(afdoImports != null,
         "AutoFDO import data missing for %s", sourceExecPath);
@@ -427,7 +476,7 @@ public class FdoSupport {
    * @param objectName the object file
    */
   private Iterable<PathFragment> getImports(PathFragment objDirectory, PathFragment objectName) {
-    Preconditions.checkState(isLipoEnabled());
+    Preconditions.checkState(lipoMode != LipoMode.OFF);
     Preconditions.checkState(imports != null,
         "Tried to look up imports of uninitialized FDOSupport");
     PathFragment key = objDirectory.getRelative(FileSystemUtils.removeExtension(objectName));
@@ -449,7 +498,7 @@ public class FdoSupport {
     // It is a bug if this method is called with useLipo if lipo is disabled. However, it is legal
     // if is is called with !useLipo, even though lipo is enabled.
     LipoContextProvider lipoInputProvider = CppHelper.getLipoContextProvider(ruleContext);
-    Preconditions.checkArgument(lipoInputProvider == null || isLipoEnabled());
+    Preconditions.checkArgument(lipoInputProvider == null || lipoMode != LipoMode.OFF);
 
     // FDO is disabled -> do nothing.
     if ((fdoInstrument == null) && (fdoRoot == null)) {
@@ -474,12 +523,12 @@ public class FdoSupport {
       if (!Iterables.isEmpty(auxiliaryInputs)) {
         if (featureConfiguration.isEnabled(CppRuleClasses.AUTOFDO)) {
           buildVariables.addVariable("fdo_profile_path",
-              getAutoProfilePath().getPathString());
+              getAutoProfilePath(fdoProfile, fdoRootExecPath).getPathString());
         }
         if (featureConfiguration.isEnabled(CppRuleClasses.FDO_OPTIMIZE)) {
-          if (useLLVMFdo) {
+          if (fdoMode == FdoMode.LLVM_FDO) {
             buildVariables.addVariable("fdo_profile_path",
-                getLLVMProfilePath().getPathString());
+                getLLVMProfilePath(fdoProfile, fdoRootExecPath).getPathString());
           } else {
             buildVariables.addVariable("fdo_profile_path",
                 fdoRootExecPath.getPathString());
@@ -498,12 +547,12 @@ public class FdoSupport {
     // If --fdo_optimize was not specified, we don't have any additional inputs.
     if (fdoProfile == null) {
       return ImmutableSet.of();
-    } else if (useAutoFdo || useLLVMFdo) {
+    } else if (fdoMode == FdoMode.AUTO_FDO || fdoMode == FdoMode.LLVM_FDO) {
       ImmutableSet.Builder<Artifact> auxiliaryInputs = ImmutableSet.builder();
 
-      PathFragment profileRootRelativePath = (useLLVMFdo)
-          ? getLLVMProfileRootRelativePath()
-          : getAutoProfileRootRelativePath();
+      PathFragment profileRootRelativePath = fdoMode == FdoMode.LLVM_FDO
+          ? getLLVMProfileRootRelativePath(fdoProfile)
+          : getAutoProfileRootRelativePath(fdoProfile);
       Artifact artifact = env.getDerivedArtifact(
           fdoPath.getRelative(profileRootRelativePath), fdoRoot);
       env.registerAction(new FdoStubAction(ruleContext.getActionOwner(), artifact));
@@ -607,37 +656,29 @@ public class FdoSupport {
   }
 
 
-  private PathFragment getAutoProfilePath() {
-    return fdoRootExecPath.getRelative(getAutoProfileRootRelativePath());
+  private static PathFragment getAutoProfilePath(Path fdoProfile, PathFragment fdoRootExecPath) {
+    return fdoRootExecPath.getRelative(getAutoProfileRootRelativePath(fdoProfile));
   }
 
-  private PathFragment getAutoProfileRootRelativePath() {
+  private static PathFragment getAutoProfileRootRelativePath(Path fdoProfile) {
     return new PathFragment(fdoProfile.getBaseName());
   }
 
 
-  private PathFragment getLLVMProfilePath() {
-    return fdoRootExecPath.getRelative(getLLVMProfileRootRelativePath());
+  private static PathFragment getLLVMProfilePath(Path fdoProfile, PathFragment fdoRootExecPath) {
+    return fdoRootExecPath.getRelative(getLLVMProfileRootRelativePath(fdoProfile));
   }
 
-  private PathFragment getLLVMProfileRootRelativePath() {
+  private static PathFragment getLLVMProfileRootRelativePath(Path fdoProfile) {
     return new PathFragment(fdoProfile.getBaseName());
   }
 
   /**
-   * Returns whether LIPO is enabled.
-   */
-  @ThreadSafe
-  public boolean isLipoEnabled() {
-    return fdoProfile != null && lipoMode != LipoMode.OFF;
-  }
-
-  /**
    * Returns whether AutoFDO is enabled.
    */
   @ThreadSafe
   public boolean isAutoFdoEnabled() {
-    return useAutoFdo;
+    return fdoMode == FdoMode.AUTO_FDO;
   }
 
   /**
@@ -664,29 +705,6 @@ public class FdoSupport {
   }
 
   /**
-   * Returns the path of the FDO zip containing the .gcda profile files, or null
-   * if FDO is not enabled.
-   */
-  @VisibleForTesting
-  public Path getFdoOptimizeProfile() {
-    return fdoProfile;
-  }
-
-  /**
-   * Returns the path fragment of the instrumentation output dir for gcc when
-   * FDO is enabled, or null if FDO is not enabled.
-   */
-  @ThreadSafe
-  public PathFragment getFdoInstrument() {
-    return fdoInstrument;
-  }
-
-  @VisibleForTesting
-  public void setGcdaFilesForTesting(ImmutableSet<PathFragment> gcdaFiles) {
-    this.gcdaFiles = gcdaFiles;
-  }
-
-  /**
    * An exception indicating an issue with FDO coverage files.
    */
   public static final class FdoException extends Exception {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportFunction.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportFunction.java
new file mode 100644
index 0000000000..b232a31582
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportFunction.java
@@ -0,0 +1,76 @@
+// Copyright 2014 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.rules.cpp;
+
+import com.google.devtools.build.lib.analysis.BlazeDirectories;
+import com.google.devtools.build.lib.rules.cpp.FdoSupport.FdoException;
+import com.google.devtools.build.lib.skyframe.PrecomputedValue;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import java.io.IOException;
+
+import javax.annotation.Nullable;
+
+/**
+ * Wrapper for {@link FdoSupport} that turns it into a {@link SkyFunction}.
+ */
+public class FdoSupportFunction implements SkyFunction {
+
+  /**
+   * Wrapper for FDO exceptions.
+   */
+  public class FdoSkyException extends SkyFunctionException {
+    public FdoSkyException(Exception cause, Transience transience) {
+      super(cause, transience);
+    }
+  }
+
+  @Nullable
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env)
+      throws FdoSkyException, InterruptedException {
+    BlazeDirectories blazeDirectories = PrecomputedValue.BLAZE_DIRECTORIES.get(env);
+    if (env.valuesMissing()) {
+      return null;
+    }
+
+    Path execRoot = blazeDirectories.getExecRoot();
+    FdoSupportValue.Key key = (FdoSupportValue.Key) skyKey.argument();
+    FdoSupport fdoSupport;
+    try {
+      fdoSupport = FdoSupport.create(env,
+        key.getFdoInstrument(), key.getFdoZip(), key.getLipoMode(), execRoot);
+      if (env.valuesMissing()) {
+        return null;
+      }
+    } catch (FdoException e) {
+      throw new FdoSkyException(e, Transience.PERSISTENT);
+    } catch (IOException e) {
+      throw new FdoSkyException(e, Transience.TRANSIENT);
+    }
+
+    return new FdoSupportValue(fdoSupport);
+  }
+
+  @Nullable
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return null;
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportProvider.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportProvider.java
new file mode 100644
index 0000000000..f97621421a
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportProvider.java
@@ -0,0 +1,34 @@
+// Copyright 2014 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.rules.cpp;
+
+import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+
+/**
+ * A {@link TransitiveInfoProvider} so that {@code cc_toolchain} can pass {@link FdoSupport} to the
+ * C++ rules.
+ */
+@Immutable
+public class FdoSupportProvider implements TransitiveInfoProvider {
+  private final FdoSupport fdoSupport;
+
+  public FdoSupportProvider(FdoSupport fdoSupport) {
+    this.fdoSupport = fdoSupport;
+  }
+
+  public FdoSupport getFdoSupport() {
+    return fdoSupport;
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportValue.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportValue.java
new file mode 100644
index 0000000000..eb03db6a3f
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/FdoSupportValue.java
@@ -0,0 +1,101 @@
+// Copyright 2014 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.rules.cpp;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
+import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.LipoMode;
+import com.google.devtools.build.skyframe.SkyFunctionName;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import java.util.Objects;
+
+/**
+ * Wrapper for {@link FdoSupport}.
+ *
+ * <p>Things could probably be refactored such the attributes of {@link FdoSupport} are moved here
+ * and the code in it to {@link FdoSupportFunction}. This would let us eliminate {@link FdoSupport}.
+ *
+ * <p>The eventual plan is to migrate FDO functionality to the execution phase once directory
+ * artifacts work better, so this may not be worth it.
+ */
+@Immutable
+public class FdoSupportValue implements SkyValue {
+  public static final SkyFunctionName SKYFUNCTION = SkyFunctionName.create("FDO_SUPPORT");
+
+  /**
+   * {@link SkyKey} for {@link FdoSupportValue}.
+   */
+  @Immutable
+  public static class Key {
+    private final LipoMode lipoMode;
+    private final Path fdoZip;
+    private final PathFragment fdoInstrument;
+
+    private Key(LipoMode lipoMode, Path fdoZip, PathFragment fdoInstrument) {
+      this.lipoMode = lipoMode;
+      this.fdoZip = fdoZip;
+      this.fdoInstrument = fdoInstrument;
+    }
+
+    public LipoMode getLipoMode() {
+      return lipoMode;
+    }
+
+    public Path getFdoZip() {
+      return fdoZip;
+    }
+
+    public PathFragment getFdoInstrument() {
+      return fdoInstrument;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+
+      if (!(o instanceof Key)) {
+        return false;
+      }
+
+      Key that = (Key) o;
+      return Objects.equals(this.lipoMode, that.lipoMode)
+          && Objects.equals(this.fdoZip, that.fdoZip)
+          && Objects.equals(this.fdoInstrument, that.fdoInstrument);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(lipoMode, fdoZip, fdoInstrument);
+    }
+  }
+
+  private final FdoSupport fdoSupport;
+
+  FdoSupportValue(FdoSupport fdoSupport) {
+    this.fdoSupport = fdoSupport;
+  }
+
+  public FdoSupport getFdoSupport() {
+    return fdoSupport;
+  }
+
+  public static SkyKey key(LipoMode lipoMode, Path fdoZip, PathFragment fdoInstrument) {
+    return SkyKey.create(SKYFUNCTION, new Key(lipoMode, fdoZip, fdoInstrument));
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
index 98ed76fa10..79c24e6bef 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
@@ -75,6 +75,7 @@ public final class LinkCommandLine extends CommandLine {
   private final ImmutableSet<String> features;
   private final ImmutableMap<Artifact, Artifact> linkstamps;
   private final ImmutableList<String> linkstampCompileOptions;
+  @Nullable private final String fdoBuildStamp;
   @Nullable private final PathFragment runtimeSolibDir;
   private final boolean nativeDeps;
   private final boolean useTestOnlyFlags;
@@ -84,6 +85,7 @@ public final class LinkCommandLine extends CommandLine {
   @Nullable private final Artifact paramFile;
   @Nullable private final Artifact interfaceSoBuilder;
 
+
   /**
    * A string constant for the c++ link action, used to access the feature
    * configuration.
@@ -105,6 +107,7 @@ public final class LinkCommandLine extends CommandLine {
       ImmutableSet<String> features,
       ImmutableMap<Artifact, Artifact> linkstamps,
       ImmutableList<String> linkstampCompileOptions,
+      @Nullable String fdoBuildStamp,
       @Nullable PathFragment runtimeSolibDir,
       boolean nativeDeps,
       boolean useTestOnlyFlags,
@@ -161,6 +164,7 @@ public final class LinkCommandLine extends CommandLine {
     this.features = Preconditions.checkNotNull(features);
     this.linkstamps = Preconditions.checkNotNull(linkstamps);
     this.linkstampCompileOptions = linkstampCompileOptions;
+    this.fdoBuildStamp = fdoBuildStamp;
     this.runtimeSolibDir = runtimeSolibDir;
     this.nativeDeps = nativeDeps;
     this.useTestOnlyFlags = useTestOnlyFlags;
@@ -590,7 +594,6 @@ public final class LinkCommandLine extends CommandLine {
       }
 
       // Stamp FDO builds with FDO subtype string
-      String fdoBuildStamp = CppHelper.getFdoBuildStamp(cppConfiguration);
       if (fdoBuildStamp != null) {
         optionList.add("-D" + CppConfiguration.FDO_STAMP_MACRO + "=\"" + fdoBuildStamp + "\"");
       }
@@ -1052,8 +1055,7 @@ public final class LinkCommandLine extends CommandLine {
         }
         CcToolchainFeatures.Variables.Builder buildVariables =
             new CcToolchainFeatures.Variables.Builder();
-        CppConfiguration cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
-        cppConfiguration.getFdoSupport().getLinkOptions(featureConfiguration, buildVariables);
+        CppHelper.getFdoSupport(ruleContext).getLinkOptions(featureConfiguration, buildVariables);
         variables = buildVariables.build();
       }
       return new LinkCommandLine(
@@ -1071,6 +1073,7 @@ public final class LinkCommandLine extends CommandLine {
           features,
           linkstamps,
           actualLinkstampCompileOptions,
+          CppHelper.getFdoBuildStamp(ruleContext),
           runtimeSolibDir,
           nativeDeps,
           useTestOnlyFlags,
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java
index 9aab8b11de..0746b62134 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/PrecomputedValue.java
@@ -98,7 +98,7 @@ public final class PrecomputedValue implements SkyValue {
   public static final Precomputed<Map<BuildInfoKey, BuildInfoFactory>> BUILD_INFO_FACTORIES =
       new Precomputed<>(SkyKey.create(SkyFunctions.PRECOMPUTED, "build_info_factories"));
 
-  static final Precomputed<BlazeDirectories> BLAZE_DIRECTORIES =
+  public static final Precomputed<BlazeDirectories> BLAZE_DIRECTORIES =
       new Precomputed<>(SkyKey.create(SkyFunctions.PRECOMPUTED, "blaze_directories"));
 
   static final Precomputed<ImmutableMap<Action, ConflictException>> BAD_ACTIONS =
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/ZipFileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/ZipFileSystem.java
index 393110d5f8..4830d8fe19 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/ZipFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/ZipFileSystem.java
@@ -15,11 +15,15 @@ package com.google.devtools.build.lib.vfs;
 
 import com.google.common.base.Predicate;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
+import com.google.devtools.build.lib.util.Preconditions;
 
+import java.io.Closeable;
 import java.io.File;
 import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -31,9 +35,11 @@ import java.util.zip.ZipFile;
  * Inherits the constraints imposed by ReadonlyFileSystem.
  */
 @ThreadSafe
-public class ZipFileSystem extends ReadonlyFileSystem {
+public class ZipFileSystem extends ReadonlyFileSystem implements Closeable {
 
+  private final File tempFile;  // In case this needs to be written to the file system
   private final ZipFile zipFile;
+  private boolean open;
 
   /**
    * The sole purpose of this field is to hold a strong reference to all leaf
@@ -53,14 +59,25 @@ public class ZipFileSystem extends ReadonlyFileSystem {
    * Constructs a ZipFileSystem from a zip file identified with a given path.
    */
   public ZipFileSystem(Path zipPath) throws IOException {
-    // Throw some more specific exceptions than ZipFile does.
-    // We do this using File instead of Path, in case zipPath points to an
-    // InMemoryFileSystem. This case is not really supported but
-    // can occur in tests.
+    if (!zipPath.exists()) {
+      throw new FileNotFoundException(String.format("File '%s' does not exist", zipPath));
+    }
+
     File file = zipPath.getPathFile();
     if (!file.exists()) {
-      throw new FileNotFoundException(String.format("File '%s' does not exist", zipPath));
+      // If the File says that it does not exist but the Path says that it does, we are probably
+      // dealing with a FileSystem that does not represent the actual file system we are running
+      // under. Then we copy the Path into a temporary File.
+      tempFile = File.createTempFile("bazel.test.", ".tmp");
+      file = tempFile;
+      byte[] contents = FileSystemUtils.readContent(zipPath);
+      try (OutputStream os = new FileOutputStream(tempFile)) {
+        os.write(contents);
+      }
+    } else {
+      tempFile = null;
     }
+
     if (!file.isFile()) {
       throw new IOException(String.format("'%s' is not a file", zipPath));
     }
@@ -70,6 +87,7 @@ public class ZipFileSystem extends ReadonlyFileSystem {
 
     this.zipFile = new ZipFile(file);
     this.paths = populatePathTree();
+    this.open = true;
   }
 
   // ZipPath extends Path with a set-once ZipEntry field.
@@ -160,12 +178,14 @@ public class ZipFileSystem extends ReadonlyFileSystem {
 
   @Override
   protected InputStream getInputStream(Path path) throws IOException {
+    Preconditions.checkState(open);
     return zipFile.getInputStream(zipEntryNonNull(path));
   }
 
   @Override
   protected Collection<Path> getDirectoryEntries(Path path)
       throws IOException {
+    Preconditions.checkState(open);
     zipEntryNonNull(path);
     final Collection<Path> result = new ArrayList<>();
     ((ZipPath) path).applyToChildren(new Predicate<Path>() {
@@ -182,46 +202,54 @@ public class ZipFileSystem extends ReadonlyFileSystem {
 
   @Override
   protected boolean exists(Path path, boolean followSymlinks) {
+    Preconditions.checkState(open);
     return zipEntry(path) != null;
   }
 
   @Override
   protected boolean isDirectory(Path path, boolean followSymlinks) {
+    Preconditions.checkState(open);
     ZipEntry entry = zipEntry(path);
     return entry != null && entry.isDirectory();
   }
 
   @Override
   protected boolean isFile(Path path, boolean followSymlinks) {
+    Preconditions.checkState(open);
     ZipEntry entry = zipEntry(path);
     return entry != null && !entry.isDirectory();
   }
 
   @Override
   protected boolean isSpecialFile(Path path, boolean followSymlinks) {
+    Preconditions.checkState(open);
     return false;
   }
 
   @Override
   protected boolean isReadable(Path path) throws IOException {
+    Preconditions.checkState(open);
     zipEntryNonNull(path);
     return true;
   }
 
   @Override
   protected boolean isWritable(Path path) throws IOException {
+    Preconditions.checkState(open);
     zipEntryNonNull(path);
     return false;
   }
 
   @Override
   protected boolean isExecutable(Path path) throws IOException {
+    Preconditions.checkState(open);
     zipEntryNonNull(path);
     return false;
   }
 
   @Override
   protected PathFragment readSymbolicLink(Path path) throws IOException {
+    Preconditions.checkState(open);
     zipEntryNonNull(path);
     throw new NotASymlinkException(path);
   }
@@ -229,22 +257,26 @@ public class ZipFileSystem extends ReadonlyFileSystem {
   @Override
   protected long getFileSize(Path path, boolean followSymlinks)
       throws IOException {
+    Preconditions.checkState(open);
     return zipEntryNonNull(path).getSize();
   }
 
   @Override
   protected long getLastModifiedTime(Path path, boolean followSymlinks)
       throws FileNotFoundException {
+    Preconditions.checkState(open);
     return zipEntryNonNull(path).getTime();
   }
 
   @Override
   protected boolean isSymbolicLink(Path path) {
+    Preconditions.checkState(open);
     return false;
   }
 
   @Override
   protected FileStatus statIfFound(Path path, boolean followSymlinks) {
+    Preconditions.checkState(open);
     try {
       return stat(path, followSymlinks);
     } catch (FileNotFoundException e) {
@@ -255,4 +287,14 @@ public class ZipFileSystem extends ReadonlyFileSystem {
     }
   }
 
+  @Override
+  public void close() {
+    if (open) {
+      close();
+      if (tempFile != null) {
+        tempFile.delete();
+      }
+      open = false;
+    }
+  }
 }