scala.scalanative.optimizer.pass.SafepointInsertion.scala Maven / Gradle / Ivy

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package scala.scalanative
package optimizer
package pass

import scala.collection.mutable
import analysis.ClassHierarchy.Top
import nir._

/** Inserts safepoint probes before every return. */
class SafepointInsertion(implicit fresh: Fresh) extends Pass {
  import SafepointInsertion._

  override def onDefns(defns: Seq[Defn]): Seq[Defn] = {
    val buf = mutable.UnrolledBuffer.empty[Defn]

    defns.foreach {
      case defn: Defn.Define if defn.attrs.inline ne Attr.AlwaysInline =>
        buf += defn.copy(insts = onInsts(defn.insts))

      case defn =>
        buf += defn
    }

    buf
  }

  override def onInsts(insts: Seq[Inst]): Seq[Inst] = {
    val buf = new nir.Buffer
    import buf._

    insts.foreach {
      case inst: Inst.Ret =>
        let(Op.Load(Type.Byte, safepointTriggerVal, isVolatile = true))
        buf += inst

      case inst =>
        buf += inst
    }

    buf.toSeq
  }
}

object SafepointInsertion extends PassCompanion {
  val safepointTriggerName = Global.Top("scalanative_safepoint_trigger")
  val safepointTriggerVal  = Val.Global(safepointTriggerName, Type.Ptr)

  override def apply(config: tools.Config, top: Top) =
    new SafepointInsertion()(top.fresh)
}