Use rule machinery for handling Symbolic Macro attrs in order to reduce the memory overhead of symbolic macros.

In particular, RuleOrMacroInstance holds shared logic between Rule and MacroInstance, and both RuleClass and MacroClass now hold an AttributeProvider, which gives access to their Attributes.

Together, this gives us:
- Use of the package's list interner for attributes
- Map of Attributes is now a list (the key/name is already stored in the attribute)
- Default values of Attributes are not stored
- Compact attr representation once the macro is frozen
- Attrs are stored as Native types instead of Starlark types

As a side effect of doing this, Attribute.valueToStarlark() now works with Selects.

PiperOrigin-RevId: 739568597
Change-Id: Ia6219f3105ede816c08105fec6c0df03d7b8a5e6

Author: susinmotion

src/main/java/com/google/devtools/build/docgen/BuildDocCollector.java

@@ -207,7 +207,7 @@ private void processJavaSourceRuleAttributeDocs(
         if (ruleClass.isDocumented()) {
           Class<? extends RuleDefinition> ruleDefinition =
               ruleClassProvider.getRuleClassDefinition(ruleDoc.getRuleName()).getClass();
-          for (Attribute attribute : ruleClass.getAttributes()) {
+          for (Attribute attribute : ruleClass.getAttributeProvider().getAttributes()) {
             if (!attribute.isDocumented()) {
               continue;
             }

src/main/java/com/google/devtools/build/lib/analysis/DependencyResolutionHelpers.java

@@ -510,7 +510,8 @@ private static void addExplicitDeps(
         && !rule.isAttrDefined(attrName, BuildType.NODEP_LABEL_LIST)) {
       return;
     }
-    Attribute attribute = rule.getRuleClassObject().getAttributeByName(attrName);
+    Attribute attribute =
+        rule.getRuleClassObject().getAttributeProvider().getAttributeByName(attrName);
     outgoingLabels.putAll(AttributeDependencyKind.forRule(attribute), labels);
   }
 
@@ -528,7 +529,8 @@ private static ImmutableList<AttributeDependencyKind> getAttributes(
     // `ctx.rule.attr` with rule attributes taking precedence then aspects' attributes based on the
     // aspect order in the aspects path (lowest order to highest).
 
-    List<Attribute> ruleAttributes = rule.getRuleClassObject().getAttributes();
+    List<Attribute> ruleAttributes =
+        rule.getRuleClassObject().getAttributeProvider().getAttributes();
     for (Attribute attribute : ruleAttributes) {
         result.add(AttributeDependencyKind.forRule(attribute));
       ruleAndBaseAspectsProcessedAttributes.add(attribute.getName());

src/main/java/com/google/devtools/build/lib/analysis/RequiredFragmentsUtil.java

@@ -248,7 +248,7 @@ private static void addRequiredFragmentsFromRuleTransitions(
             .attributes(attributeMap)
             .analysisData(starlarkExecTransition)
             .build();
-    for (Attribute attribute : target.getRuleClassObject().getAttributes()) {
+    for (Attribute attribute : target.getRuleClassObject().getAttributeProvider().getAttributes()) {
       if (attribute.getTransitionFactory() != null) {
         attribute
             .getTransitionFactory()

src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java

@@ -2169,7 +2169,7 @@ protected String getMacroMessageAppendix(String unusedAttrName) {
       // but we no longer locations for individual attributes.
       // We should record the instantiation call stack in each rule
       // and report the position of its topmost frame here.
-      return rule.wasCreatedByMacro()
+      return rule.isRuleCreatedInLegacyMacro()
           ? String.format(
               ". Since this rule was created by the macro '%s', the error might have been "
                   + "caused by the macro implementation",

src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkRuleClassFunctions.java

@@ -466,12 +466,12 @@ private static ImmutableList<Attribute> getAttrsOf(Object inheritAttrsArg) throw
       return ImmutableList.of();
     } else if (inheritAttrsArg instanceof RuleFunction ruleFunction) {
       verifyInheritAttrsArgExportedIfExportable(ruleFunction);
-      return ruleFunction.getRuleClass().getAttributes();
+      return ruleFunction.getRuleClass().getAttributeProvider().getAttributes();
     } else if (inheritAttrsArg instanceof MacroFunction macroFunction) {
       verifyInheritAttrsArgExportedIfExportable(macroFunction);
-      return macroFunction.getMacroClass().getAttributes().values().asList();
+      return macroFunction.getMacroClass().getAttributeProvider().getAttributes();
     } else if (inheritAttrsArg.equals(COMMON_ATTRIBUTES_NAME)) {
-      return baseRule.getAttributes();
+      return baseRule.getAttributeProvider().getAttributes();
     }
     throw Starlark.errorf(
         "Invalid 'inherit_attrs' value %s; expected a rule, a macro, or \"common\"",
@@ -1390,7 +1390,8 @@ public StarlarkAspect aspect(
   }
 
   private static ImmutableSet<String> getLegacyAnyTypeAttrs(RuleClass ruleClass) {
-    Attribute attr = ruleClass.getAttributeByNameMaybe("$legacy_any_type_attrs");
+    Attribute attr =
+        ruleClass.getAttributeProvider().getAttributeByNameMaybe("$legacy_any_type_attrs");
     if (attr == null
         || attr.getType() != STRING_LIST
         || !(attr.getDefaultValueUnchecked() instanceof List<?>)) {
@@ -1677,7 +1678,7 @@ public Object call(StarlarkThread thread, Tuple args, Dict<String, Object> kwarg
           // users.
           // The less magic the better. Do not give in those temptations!
           Dict.Builder<String, Object> initializerKwargs = Dict.builder();
-          for (var attr : currentRuleClass.getAttributes()) {
+          for (var attr : currentRuleClass.getAttributeProvider().getAttributes()) {
             if ((attr.isPublic() && attr.starlarkDefined()) || attr.getName().equals("name")) {
               if (kwargs.containsKey(attr.getName())) {
                 Object value = kwargs.get(attr.getName());
@@ -1724,7 +1725,8 @@ public Object call(StarlarkThread thread, Tuple args, Dict<String, Object> kwarg
                   ALLOWLIST_RULE_EXTENSION_API_EXPERIMENTAL);
             }
             String nativeName = arg.startsWith("_") ? "$" + arg.substring(1) : arg;
-            Attribute attr = currentRuleClass.getAttributeByNameMaybe(nativeName);
+            Attribute attr =
+                currentRuleClass.getAttributeProvider().getAttributeByNameMaybe(nativeName);
             if (attr != null && !attr.starlarkDefined()) {
               throw Starlark.errorf(
                   "Initializer can only set Starlark defined attributes, not '%s'", arg);
@@ -1770,7 +1772,7 @@ public Object call(StarlarkThread thread, Tuple args, Dict<String, Object> kwarg
     }
 
     private static void validateRulePropagatedAspects(RuleClass ruleClass) throws EvalException {
-      for (Attribute attribute : ruleClass.getAttributes()) {
+      for (Attribute attribute : ruleClass.getAttributeProvider().getAttributes()) {
         attribute.validateRulePropagatedAspectsParameters(ruleClass);
       }
     }

src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkSubrule.java

@@ -201,7 +201,12 @@ private static Attribute getAttributeByName(StarlarkRuleContext ruleContext, Str
     if (ruleContext.isForAspect()) {
       return ruleContext.getRuleContext().getMainAspect().getDefinition().getAttributes().get(attr);
     } else {
-      return ruleContext.getRuleContext().getRule().getRuleClassObject().getAttributeByName(attr);
+      return ruleContext
+          .getRuleContext()
+          .getRule()
+          .getRuleClassObject()
+          .getAttributeProvider()
+          .getAttributeByName(attr);
     }
   }
 

src/main/java/com/google/devtools/build/lib/analysis/test/InstrumentedFilesCollector.java

@@ -456,7 +456,11 @@ private static Iterable<TransitiveInfoCollection> getPrerequisitesForAttributes(
     List<TransitiveInfoCollection> prerequisites = new ArrayList<>();
     for (String attributeName : attributeNames) {
       Attribute attribute =
-          ruleContext.getRule().getRuleClassObject().getAttributeByNameMaybe(attributeName);
+          ruleContext
+              .getRule()
+              .getRuleClassObject()
+              .getAttributeProvider()
+              .getAttributeByNameMaybe(attributeName);
       if (attribute != null) {
         prerequisites.addAll(attributeDependencyPrerequisites(attribute, ruleContext));
       }

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

@@ -31,19 +31,19 @@
  * data before exposing it to consumers.
  */
 public abstract class AbstractAttributeMapper implements AttributeMap {
-  final RuleClass ruleClass;
-  final Rule rule;
+  final AttributeProvider ruleClass;
+  final RuleOrMacroInstance rule;
   private final Label ruleLabel;
 
-  protected AbstractAttributeMapper(Rule rule) {
-    this.ruleClass = rule.getRuleClassObject();
+  protected AbstractAttributeMapper(RuleOrMacroInstance rule) {
+    this.ruleClass = rule.getAttributeProvider();
     this.ruleLabel = rule.getLabel();
     this.rule = rule;
   }
 
   @Override
   public String describeRule() {
-    return String.format("%s %s", this.rule.getRuleClass(), getLabel());
+    return String.format("%s %s", this.rule.getAttributeProvider(), getLabel());
   }
 
   @Override
@@ -149,7 +149,7 @@ public boolean isAttributeValueExplicitlySpecified(String attributeName) {
 
   @Override
   public PackageArgs getPackageArgs() {
-    return rule.getPackageDeclarations().getPackageArgs();
+    return rule.getPackageArgs();
   }
 
   @Override
@@ -209,7 +209,7 @@ public final boolean isConfigurable(String attributeName) {
    * Check if an attribute is configurable (uses select) or, if it's a computed default, if any of
    * its inputs are configurable.
    */
-  public static boolean isConfigurable(Rule rule, String attributeName) {
+  public static boolean isConfigurable(RuleOrMacroInstance rule, String attributeName) {
     Object attr = rule.getAttr(attributeName);
     if (attr instanceof Attribute.ComputedDefault) {
       for (String dep : ((Attribute.ComputedDefault) attr).dependencies()) {
@@ -219,7 +219,7 @@ public static boolean isConfigurable(Rule rule, String attributeName) {
       }
       return false;
     }
-    Attribute attrDef = rule.getRuleClassObject().getAttributeByNameMaybe(attributeName);
+    Attribute attrDef = rule.getAttributeProvider().getAttributeByNameMaybe(attributeName);
     return attrDef != null && rule.getSelectorList(attributeName, attrDef.getType()) != null;
   }
 

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

@@ -48,11 +48,11 @@
  */
 public class AggregatingAttributeMapper extends AbstractAttributeMapper {
 
-  private AggregatingAttributeMapper(Rule rule) {
+  private AggregatingAttributeMapper(RuleOrMacroInstance rule) {
     super(rule);
   }
 
-  public static AggregatingAttributeMapper of(Rule rule) {
+  public static AggregatingAttributeMapper of(RuleOrMacroInstance rule) {
     return new AggregatingAttributeMapper(rule);
   }
 
@@ -61,7 +61,7 @@ public static AggregatingAttributeMapper of(Rule rule) {
    * available to computed defaults no matter what dependencies they've declared.
    */
   private List<String> getNonConfigurableAttributes() {
-    return rule.getRuleClassObject().getNonConfigurableAttributes();
+    return rule.getAttributeProvider().getNonConfigurableAttributes();
   }
 
   /**
@@ -184,7 +184,7 @@ public static <T> void visitLabelsInSelect(
       Attribute attribute,
       Type<T> type,
       Type.LabelVisitor visitor,
-      @Nullable Rule rule,
+      @Nullable RuleOrMacroInstance rule,
       boolean includeKeys,
       boolean includeValues) {
     var entryProcessor =

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

@@ -104,7 +104,7 @@ public void validateRulePropagatedAspectsParameters(RuleClass ruleClass) throws
         // Required aspect parameters must be specified by the rule propagating the aspect with
         // the same parameter type.
         if (requiredAspectParameters.contains(aspectAttrName)) {
-          if (!ruleClass.hasAttr(aspectAttrName, aspectAttrType)) {
+          if (!ruleClass.getAttributeProvider().hasAttr(aspectAttrName, aspectAttrType)) {
             throw Starlark.errorf(
                 "Aspect %s requires rule %s to specify attribute '%s' with type %s.",
                 aspect.getName(), ruleClass.getName(), aspectAttrName, aspectAttrType);