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JVM_IR KT-47398 handle @EnhancedNullability String subject as in 1.0

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This commit is contained in:
Dmitry Petrov
2021-06-23 13:40:25 +03:00
committed by teamcityserver
parent c26d71c4ef
commit 0104b1275f
8 changed files with 208 additions and 4 deletions
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compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/SwitchGenerator.kt
+15 -4
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@@ -9,10 +9,11 @@ import org.jetbrains.kotlin.codegen.`when`.SwitchCodegen.Companion.preferLookupO
import org.jetbrains.kotlin.ir.expressions.*
import org.jetbrains.kotlin.ir.types.*
import org.jetbrains.kotlin.ir.util.dump
import org.jetbrains.kotlin.ir.util.hasAnnotation
import org.jetbrains.kotlin.ir.util.isTrueConst
import org.jetbrains.kotlin.load.java.JvmAnnotationNames
import org.jetbrains.org.objectweb.asm.Label
import org.jetbrains.org.objectweb.asm.Type
import java.util.*
// TODO: eliminate the temporary variable
class SwitchGenerator(private val expression: IrWhen, private val data: BlockInfo, private val codegen: ExpressionCodegen) {
@@ -446,9 +447,19 @@ class SwitchGenerator(private val expression: IrWhen, private val data: BlockInf
hashAndSwitchLabels.add(ValueToLabel(key, Label()))
}
// Using a switch, the subject string has to be traversed at least twice (hash + comparison * N, where N is #strings hashed into the
// same bucket). The optimization isn't better than an IF cascade when #switch-targets <= 2.
override fun shouldOptimize() = hashAndSwitchLabels.size > 2
// Using a switch, the subject string has to be traversed at least twice
// (hash + comparison * N, where N is #strings hashed into the same bucket).
// The optimization isn't better than an IF cascade when #switch-targets <= 2.
//
// Generate "optimized" version for @EnhancedNullability subject type
// to model 1.0 behavior causing NPE in case of null value.
// TODO make 'when' with String subject behavior consistent.
// see:
// box/when/stringOptimization/enhancedNullability.kt
// box/when/stringOptimization/flexibleNullability.kt
override fun shouldOptimize() =
hashAndSwitchLabels.size > 2 ||
subject.type.hasAnnotation(JvmAnnotationNames.ENHANCED_NULLABILITY_ANNOTATION) && hashAndSwitchLabels.isNotEmpty()
override fun genSwitch() {
with(codegen) {