Reduce iterator usage on hot code paths
Micro-optimize a few hot code paths which have a habit of iterating over short O(1)-access
lists.
RELNOTES: None
PiperOrigin-RevId: 171347524
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
index 133cc00..1b943ec 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
@@ -192,11 +192,11 @@
private final Expression function;
- private final List<Argument.Passed> arguments;
+ private final ImmutableList<Argument.Passed> arguments;
private final int numPositionalArgs;
- public FuncallExpression(Expression function, List<Argument.Passed> arguments) {
+ public FuncallExpression(Expression function, ImmutableList<Argument.Passed> arguments) {
this.function = Preconditions.checkNotNull(function);
this.arguments = Preconditions.checkNotNull(arguments);
this.numPositionalArgs = countPositionalArguments();
@@ -679,7 +679,10 @@
// or star arguments, because the argument list was already validated by
// Argument#validateFuncallArguments, as called by the Parser,
// which should be the only place that build FuncallExpression-s.
- for (Argument.Passed arg : arguments) {
+ // Argument lists are typically short and functions are frequently called, so go by index
+ // (O(1) for ImmutableList) to avoid the iterator overhead.
+ for (int i = 0; i < arguments.size(); i++) {
+ Argument.Passed arg = arguments.get(i);
Object value = arg.getValue().eval(env);
if (arg.isPositional()) {
posargs.add(value);
