Inject the prelude path through the rule class provider.

--
MOS_MIGRATED_REVID=102020499
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredRuleClassProvider.java b/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredRuleClassProvider.java
index 3bea243..8f048f7 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredRuleClassProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredRuleClassProvider.java
@@ -18,6 +18,7 @@
 import static com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType.ABSTRACT;
 import static com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType.TEST;
 
+import com.google.common.base.Preconditions;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
@@ -41,6 +42,7 @@
 import com.google.devtools.build.lib.syntax.SkylarkEnvironment;
 import com.google.devtools.build.lib.syntax.SkylarkType;
 import com.google.devtools.build.lib.syntax.ValidationEnvironment;
+import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.common.options.OptionsClassProvider;
 
 import java.lang.reflect.Constructor;
@@ -77,6 +79,7 @@
    */
   public static class Builder implements RuleDefinitionEnvironment {
     private final StringBuilder defaultWorkspaceFile = new StringBuilder();
+    private PathFragment preludePath;
     private final List<ConfigurationFragmentFactory> configurationFragments = new ArrayList<>();
     private final List<BuildInfoFactory> buildInfoFactories = new ArrayList<>();
     private final List<Class<? extends FragmentOptions>> configurationOptions = new ArrayList<>();
@@ -99,6 +102,14 @@
       defaultWorkspaceFile.append(contents);
     }
 
+    public Builder setPrelude(String workspaceRelativePath) {
+      PathFragment preludePathFragment = new PathFragment(workspaceRelativePath);
+      Preconditions.checkArgument(!preludePathFragment.isAbsolute());
+      Preconditions.checkArgument(preludePathFragment.isNormalized());
+      this.preludePath = preludePathFragment;
+      return this;
+    }
+
     public Builder setPrerequisiteValidator(PrerequisiteValidator prerequisiteValidator) {
       this.prerequisiteValidator = prerequisiteValidator;
       return this;
@@ -207,6 +218,7 @@
       }
 
       return new ConfiguredRuleClassProvider(
+          preludePath,
           ImmutableMap.copyOf(ruleClassMap),
           ImmutableMap.copyOf(ruleDefinitionMap),
           ImmutableMap.copyOf(aspectFactoryMap),
@@ -248,6 +260,11 @@
   String defaultWorkspaceFile;
 
   /**
+   * Workspace-relative path to the prelude.
+   */
+  private final PathFragment preludePath;
+
+  /**
    * Maps rule class name to the metaclass instance for that rule.
    */
   private final ImmutableMap<String, RuleClass> ruleClassMap;
@@ -286,6 +303,7 @@
   private final ValidationEnvironment skylarkValidationEnvironment;
 
   public ConfiguredRuleClassProvider(
+      PathFragment preludePath,
       ImmutableMap<String, RuleClass> ruleClassMap,
       ImmutableMap<String, Class<? extends RuleDefinition>> ruleDefinitionMap,
       ImmutableMap<String, Class<? extends AspectFactory<?, ?, ?>>> aspectFactoryMap,
@@ -296,7 +314,7 @@
       ConfigurationCollectionFactory configurationCollectionFactory,
       PrerequisiteValidator prerequisiteValidator,
       ImmutableMap<String, SkylarkType> skylarkAccessibleJavaClasses) {
-
+    this.preludePath = preludePath;
     this.ruleClassMap = ruleClassMap;
     this.ruleDefinitionMap = ruleDefinitionMap;
     this.aspectFactoryMap = aspectFactoryMap;
@@ -317,6 +335,11 @@
   }
 
   @Override
+  public PathFragment getPreludePath() {
+    return preludePath;
+  }
+
+  @Override
   public Map<String, RuleClass> getRuleClassMap() {
     return ruleClassMap;
   }