In Dagger we found a particularly slow part of our build was creating our KspArrayType$Factory
The pprof above shows that this issue is due to creating the reverseBuiltInArrayLookup map (shown below for convience):
private val builtInArrays =
mapOf(
"kotlin.BooleanArray" to KspPrimitiveType(env, env.resolver.builtIns.booleanType),
"kotlin.ByteArray" to KspPrimitiveType(env, env.resolver.builtIns.byteType),
"kotlin.CharArray" to KspPrimitiveType(env, env.resolver.builtIns.charType),
"kotlin.DoubleArray" to KspPrimitiveType(env, env.resolver.builtIns.doubleType),
"kotlin.FloatArray" to KspPrimitiveType(env, env.resolver.builtIns.floatType),
"kotlin.IntArray" to KspPrimitiveType(env, env.resolver.builtIns.intType),
"kotlin.LongArray" to KspPrimitiveType(env, env.resolver.builtIns.longType),
"kotlin.ShortArray" to KspPrimitiveType(env, env.resolver.builtIns.shortType),
)
// map from the primitive to its array
private val reverseBuiltInArrayLookup =
builtInArrays.entries.associateBy { it.value.ksType }While we ended up fixing this performance issue by caching the factory instance (which removes nearly the entire 63s), it also would have helped to have more caching at the KSP level.
For example, given that the majority of time is spent calculating hashcodes for the same 8 builtin types above, memoizing the result of KSTypeImpl.hashcode() or KSTypeImpl.fullyExpand() would have helped here, assuming these types are indeed immutable (i.e. there hashes don't change over time).
In Dagger we found a particularly slow part of our build was creating our
KspArrayType$FactoryThe pprof above shows that this issue is due to creating the
reverseBuiltInArrayLookupmap (shown below for convience):While we ended up fixing this performance issue by caching the factory instance (which removes nearly the entire 63s), it also would have helped to have more caching at the KSP level.
For example, given that the majority of time is spent calculating hashcodes for the same 8 builtin types above, memoizing the result of
KSTypeImpl.hashcode()orKSTypeImpl.fullyExpand()would have helped here, assuming these types are indeed immutable (i.e. there hashes don't change over time).