Precompute non-configurable attributes at RuleClass level

Previously we created this collection for each AggregatingAttributeMapper,
which we create at least every attribute encountered. Calculate the collection
up front to avoid wasting time and memory.

--
MOS_MIGRATED_REVID=109805907

src/main/java/com/google/devtools/build/lib/packages/AggregatingAttributeMapper.java

@@ -46,19 +46,13 @@ public class AggregatingAttributeMapper extends AbstractAttributeMapper {
    * unconditionally  available to computed defaults no matter what dependencies
    * they've declared.
    */
-  private final List<String> nonconfigurableAttributes;
+  private final List<String> nonConfigurableAttributes;
 
   private AggregatingAttributeMapper(Rule rule) {
     super(rule.getPackage(), rule.getRuleClassObject(), rule.getLabel(),
         rule.getAttributeContainer());
 
-    ImmutableList.Builder<String> nonconfigurableAttributesBuilder = ImmutableList.builder();
-    for (Attribute attr : rule.getAttributes()) {
-      if (!attr.isConfigurable()) {
-        nonconfigurableAttributesBuilder.add(attr.getName());
-      }
-    }
-    nonconfigurableAttributes = nonconfigurableAttributesBuilder.build();
+    nonConfigurableAttributes = rule.getRuleClassObject().getNonConfigurableAttributes();
   }
 
   public static AggregatingAttributeMapper of(Rule rule) {
@@ -374,7 +368,7 @@ private AttributeMap mapBackedAttributeMap(final Map<String, Object> directMap)
       @Override
       public <T> T get(String attributeName, Type<T> type) {
         owner.checkType(attributeName, type);
-        if (nonconfigurableAttributes.contains(attributeName)) {
+        if (nonConfigurableAttributes.contains(attributeName)) {
           return owner.get(attributeName, type);
         }
         if (!directMap.containsKey(attributeName)) {
@@ -393,7 +387,7 @@ public <T> boolean isConfigurable(String attributeName, Type<T> type) {
       @Override public Label getLabel() { return owner.getLabel(); }
       @Override public Iterable<String> getAttributeNames() {
         return ImmutableList.<String>builder()
-            .addAll(directMap.keySet()).addAll(nonconfigurableAttributes).build();
+            .addAll(directMap.keySet()).addAll(nonConfigurableAttributes).build();
       }
       @Override
       public void visitLabels(AcceptsLabelAttribute observer) { owner.visitLabels(observer); }

src/main/java/com/google/devtools/build/lib/packages/RuleClass.java

@@ -914,6 +914,9 @@ public Object create(Object ruleContext) throws InterruptedException {
    */
   private final ImmutableList<Attribute> attributes;
 
+  /** Names of the non-configurable attributes of this rule class. */
+  private final ImmutableList<String> nonConfigurableAttributes;
+
   /**
    * The set of implicit outputs generated by a rule, expressed as a function
    * of that rule.
@@ -1083,12 +1086,17 @@ public Object create(Object ruleContext) throws InterruptedException {
     this.configurationFragmentPolicy = configurationFragmentPolicy;
     this.supportsConstraintChecking = supportsConstraintChecking;
 
-    // create the index:
+    // Create the index and collect non-configurable attributes.
     int index = 0;
     attributeIndex = new HashMap<>(attributes.length);
+    ImmutableList.Builder<String> nonConfigurableAttributesBuilder = ImmutableList.builder();
     for (Attribute attribute : attributes) {
       attributeIndex.put(attribute.getName(), index++);
+      if (!attribute.isConfigurable()) {
+        nonConfigurableAttributesBuilder.add(attribute.getName());
+      }
     }
+    this.nonConfigurableAttributes = nonConfigurableAttributesBuilder.build();
   }
 
   private void validateNoClashInPublicNames(Attribute[] attributes) {
@@ -1214,6 +1222,11 @@ public List<Attribute> getAttributes() {
     return attributes;
   }
 
+  /** Returns set of non-configurable attribute names defined for this class of rule. */
+  public List<String> getNonConfigurableAttributes() {
+    return nonConfigurableAttributes;
+  }
+
   public PredicateWithMessage<Rule> getValidityPredicate() {
     return validityPredicate;
   }