Optimize for the common case of `generator_name` being a prefix of a rule's name.
There's a free field in `Rule`. Use this to store the prefix length and avoid storing the string as a raw attribute value. This is similar to other optimizations already made for `generator_function` and `generator_location`.
More details in the Javadoc on `Rule#generatorNamePrefixLength`.
PiperOrigin-RevId: 522703163
Change-Id: I2017545667fad07e94c178df59400741b43366c7
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Rule.java b/src/main/java/com/google/devtools/build/lib/packages/Rule.java
index 52b5826..c338f08 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Rule.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Rule.java
@@ -82,6 +82,7 @@
private static final String NAME = RuleClass.NAME_ATTRIBUTE.getName();
private static final String GENERATOR_FUNCTION = "generator_function";
private static final String GENERATOR_LOCATION = "generator_location";
+ private static final String GENERATOR_NAME = "generator_name";
private static final int ATTR_SIZE_THRESHOLD = 126;
@@ -94,6 +95,26 @@
@Nullable private final CallStack.Node interiorCallStack;
/**
+ * The length of this rule's generator name if it is a prefix of its name, otherwise zero.
+ *
+ * <p>The generator name of a rule is the {@code name} parameter passed to a macro that
+ * instantiates the rule. Most rules instantiated via macro follow this pattern:
+ *
+ * <pre>{@code
+ * def some_macro(name):
+ * some_rule(name = name + '_some_suffix')
+ * }</pre>
+ *
+ * thus resulting in a generator name which is a prefix of the rule name. In such a case, we save
+ * memory by storing the length of the generator name instead of the string. Note that this saves
+ * memory from both the storage in {@link #attrValues} and the string itself (if it is not
+ * otherwise retained). This optimization works because this field does not push the shallow heap
+ * cost of {@link Rule} beyond an 8-byte threshold. If it did, this optimization would be a net
+ * loss.
+ */
+ private int generatorNamePrefixLength = 0;
+
+ /**
* Stores attribute values, taking on one of two shapes:
*
* <ol>
@@ -452,6 +473,13 @@
// Avoid unnecessarily storing the name in attrValues - it's stored in the label.
return;
}
+ if (attrName.equals(GENERATOR_NAME)) {
+ String generatorName = (String) value;
+ if (getName().startsWith(generatorName)) {
+ generatorNamePrefixLength = generatorName.length();
+ return;
+ }
+ }
Integer attrIndex = ruleClass.getAttributeIndex(attrName);
checkArgument(attrIndex != null, "Attribute %s is not valid for this rule", attrName);
if (explicit) {
@@ -527,6 +555,10 @@
return interiorCallStack != null ? interiorCallStack.functionName() : "";
case GENERATOR_LOCATION:
return interiorCallStack != null ? getRelativeLocation() : "";
+ case GENERATOR_NAME:
+ return generatorNamePrefixLength > 0
+ ? getName().substring(0, generatorNamePrefixLength)
+ : "";
default:
return attr.getDefaultValue();
}
@@ -588,7 +620,9 @@
if (attrName.equals(NAME)) {
return true;
}
- if (attrName.equals(GENERATOR_FUNCTION) || attrName.equals(GENERATOR_LOCATION)) {
+ if (attrName.equals(GENERATOR_FUNCTION)
+ || attrName.equals(GENERATOR_LOCATION)
+ || attrName.equals(GENERATOR_NAME)) {
return wasCreatedByMacro();
}
Integer attrIndex = ruleClass.getAttributeIndex(attrName);
@@ -800,7 +834,7 @@
* Returns whether this rule was created by a macro.
*/
public boolean wasCreatedByMacro() {
- return interiorCallStack != null || hasStringAttribute("generator_name");
+ return interiorCallStack != null || hasStringAttribute(GENERATOR_NAME);
}
/** Returns the macro that generated this rule, or an empty string. */
