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Cache array length in for-in-array loop if possible

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If the range expression is not a local variable (which can be updated in
the loop body affecting loop behavior, see KT-21354), we can cache the
array length, thus turning a for-in-array loop into a simple optimizable
counter loop.

 #KT-21321 In Progress
This commit is contained in:
Dmitry Petrov
2017-11-24 17:46:54 +03:00
parent 328c67b9e8
commit e2fa613b70
10 changed files with 127 additions and 15 deletions
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compiler/backend/src/org/jetbrains/kotlin/codegen/range/ArrayRangeValue.kt
+2 -2
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@@ -23,9 +23,9 @@ import org.jetbrains.kotlin.codegen.range.inExpression.InExpressionGenerator
import org.jetbrains.kotlin.psi.KtForExpression
import org.jetbrains.kotlin.psi.KtSimpleNameExpression
class ArrayRangeValue : RangeValue {
class ArrayRangeValue(private val canCacheArrayLength: Boolean) : RangeValue {
override fun createForLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression) =
ForInArrayLoopGenerator(codegen, forExpression)
ForInArrayLoopGenerator(codegen, forExpression, canCacheArrayLength)
override fun createInExpressionGenerator(codegen: ExpressionCodegen, operatorReference: KtSimpleNameExpression): InExpressionGenerator =
CallBasedInExpressionGenerator(codegen, operatorReference)
compiler/backend/src/org/jetbrains/kotlin/codegen/range/RangeValues.kt
+8 -1
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@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.codegen.range
import org.jetbrains.kotlin.builtins.KotlinBuiltIns
import org.jetbrains.kotlin.codegen.*
import org.jetbrains.kotlin.descriptors.CallableDescriptor
import org.jetbrains.kotlin.descriptors.impl.LocalVariableDescriptor
import org.jetbrains.kotlin.name.Name
import org.jetbrains.kotlin.psi.*
import org.jetbrains.kotlin.resolve.BindingContext
@@ -44,7 +45,7 @@ fun ExpressionCodegen.createRangeValueForExpression(rangeExpression: KtExpressio
return when {
asmRangeType.sort == Type.ARRAY ->
ArrayRangeValue()
ArrayRangeValue(!isLocalVarReference(rangeExpression, bindingContext))
isPrimitiveRange(rangeType) ->
PrimitiveRangeRangeValue()
isPrimitiveProgression(rangeType) ->
@@ -56,6 +57,12 @@ fun ExpressionCodegen.createRangeValueForExpression(rangeExpression: KtExpressio
}
}
fun isLocalVarReference(rangeExpression: KtExpression, bindingContext: BindingContext): Boolean {
if (rangeExpression !is KtSimpleNameExpression) return false
val resultingDescriptor = rangeExpression.getResolvedCall(bindingContext)?.resultingDescriptor ?: return false
return resultingDescriptor is LocalVariableDescriptor && resultingDescriptor.isVar
}
private fun isSubtypeOfCharSequence(type: KotlinType, builtIns: KotlinBuiltIns) =
KotlinTypeChecker.DEFAULT.isSubtypeOf(type, builtIns.getBuiltInClassByName(Name.identifier("CharSequence")).defaultType)
compiler/backend/src/org/jetbrains/kotlin/codegen/range/forLoop/ForInArrayLoopGenerator.kt
+26 -10
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@@ -17,21 +17,25 @@
package org.jetbrains.kotlin.codegen.range.forLoop
import org.jetbrains.kotlin.builtins.KotlinBuiltIns
import org.jetbrains.kotlin.codegen.AsmUtil.boxType
import org.jetbrains.kotlin.codegen.ExpressionCodegen
import org.jetbrains.kotlin.codegen.StackValue
import org.jetbrains.kotlin.psi.KtForExpression
import org.jetbrains.kotlin.resolve.jvm.AsmTypes.OBJECT_TYPE
import org.jetbrains.kotlin.types.KotlinType
import org.jetbrains.org.objectweb.asm.Label
import org.jetbrains.org.objectweb.asm.Type
import org.jetbrains.kotlin.codegen.AsmUtil.boxType
import org.jetbrains.kotlin.codegen.ExpressionCodegen
import org.jetbrains.kotlin.codegen.StackValue
import org.jetbrains.kotlin.resolve.jvm.AsmTypes.OBJECT_TYPE
class ForInArrayLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression)
: AbstractForLoopGenerator(codegen, forExpression)
{
class ForInArrayLoopGenerator(
codegen: ExpressionCodegen,
forExpression: KtForExpression,
// We can cache array length if the corresponding range expression is not a local var.
// See https://youtrack.jetbrains.com/issue/KT-21354.
private val canCacheArrayLength: Boolean
) : AbstractForLoopGenerator(codegen, forExpression) {
private var indexVar: Int = 0
private var arrayVar: Int = 0
private var arrayLengthVar: Int = 0
private val loopRangeType: KotlinType = bindingContext.getType(forExpression.loopRange!!)!!
override fun beforeLoop() {
@@ -51,6 +55,13 @@ class ForInArrayLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForEx
v.store(arrayVar, OBJECT_TYPE)
}
if (canCacheArrayLength) {
arrayLengthVar = createLoopTempVariable(Type.INT_TYPE)
v.load(arrayVar, OBJECT_TYPE)
v.arraylength()
v.store(arrayLengthVar, Type.INT_TYPE)
}
v.iconst(0)
v.store(indexVar, Type.INT_TYPE)
}
@@ -59,8 +70,13 @@ class ForInArrayLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForEx
override fun checkPreCondition(loopExit: Label) {
v.load(indexVar, Type.INT_TYPE)
v.load(arrayVar, OBJECT_TYPE)
v.arraylength()
if (canCacheArrayLength) {
v.load(arrayLengthVar, Type.INT_TYPE)
}
else {
v.load(arrayVar, OBJECT_TYPE)
v.arraylength()
}
v.ificmpge(loopExit)
}
compiler/testData/checkLocalVariablesTable/underscoreNames.kt
Vendored
+1 -1
View File
@@ -21,7 +21,7 @@ fun box() {
}
// METHOD : UnderscoreNamesKt$box$1.invoke(LA;Ljava/lang/String;I)Ljava/lang/String;
// VARIABLE : NAME=q TYPE=Ljava/lang/String; INDEX=15
// VARIABLE : NAME=q TYPE=Ljava/lang/String; INDEX=16
// VARIABLE : NAME=d TYPE=C INDEX=11
// VARIABLE : NAME=_ TYPE=Ljava/lang/String; INDEX=10
// VARIABLE : NAME=c TYPE=C INDEX=9
compiler/testData/codegen/box/ranges/forInArrayWithArrayPropertyUpdatedInLoopBody.kt
Vendored
+12
View File
@@ -0,0 +1,12 @@
// WITH_RUNTIME
var xs = intArrayOf(1, 2, 3)
fun box(): String {
var sum = 0
for (x in xs) {
sum = sum * 10 + x
xs = IntArray(0)
}
return if (sum == 123) "OK" else "Fail: $sum"
}
compiler/testData/codegen/box/ranges/forInArrayWithArrayVarUpdatedInLoopBody.kt
Vendored
+23
View File
@@ -0,0 +1,23 @@
// WITH_RUNTIME
// IGNORE_BACKEND: JS
// In Kotlin 1.0, in a for-in-array loop, range expression is cached in
// a local variable unless it is already a local variable.
// This caused the following quirky behavior:
// if an array variable is updated in the loop body, it affects the loop
// execution (see https://youtrack.jetbrains.com/issue/KT-21354).
// Most likely it is a bug, however, fixing it right now is a breaking
// change requiring a proper deprecation loop.
// When the design decision is made, it might be required to update this
// test (e.g., by adding a proper LANGUAGE_VERSION directive).
// Note that JS back-end handles this case "correctly".
fun box(): String {
var xs = intArrayOf(1, 2, 3)
var sum = 0
for (x in xs) {
sum = sum * 10 + x
xs = intArrayOf(4, 5)
}
return if (sum == 15) "OK" else "Fail: $sum"
}
compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
+12
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@@ -14537,6 +14537,18 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayPropertyUpdatedInLoopBody.kt")
public void testForInArrayWithArrayPropertyUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayPropertyUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayVarUpdatedInLoopBody.kt")
public void testForInArrayWithArrayVarUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayVarUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInRangeLiteralWithMixedTypeBounds.kt")
public void testForInRangeLiteralWithMixedTypeBounds() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeLiteralWithMixedTypeBounds.kt");
compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
+12
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@@ -14537,6 +14537,18 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayPropertyUpdatedInLoopBody.kt")
public void testForInArrayWithArrayPropertyUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayPropertyUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayVarUpdatedInLoopBody.kt")
public void testForInArrayWithArrayVarUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayVarUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInRangeLiteralWithMixedTypeBounds.kt")
public void testForInRangeLiteralWithMixedTypeBounds() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeLiteralWithMixedTypeBounds.kt");
compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+12
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@@ -14537,6 +14537,18 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayPropertyUpdatedInLoopBody.kt")
public void testForInArrayWithArrayPropertyUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayPropertyUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayVarUpdatedInLoopBody.kt")
public void testForInArrayWithArrayVarUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayVarUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInRangeLiteralWithMixedTypeBounds.kt")
public void testForInRangeLiteralWithMixedTypeBounds() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeLiteralWithMixedTypeBounds.kt");
js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+19 -1
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@@ -26,7 +26,7 @@ import org.junit.runner.RunWith;
import java.io.File;
import java.util.regex.Pattern;
/** This class is generated by {@link org.jetbrains.kotlin.generators.tests.TestsPackage}. DO NOT MODIFY MANUALLY */
/** This class is generated by {@link org.jetbrains.kotlin.generators.tests.TestsPackage}. DO NOT MODIFY MANUALLY test*/
@SuppressWarnings("all")
@TestMetadata("compiler/testData/codegen/box")
@TestDataPath("$PROJECT_ROOT")
@@ -15803,6 +15803,24 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayPropertyUpdatedInLoopBody.kt")
public void testForInArrayWithArrayPropertyUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayPropertyUpdatedInLoopBody.kt");
doTest(fileName);
}
@TestMetadata("forInArrayWithArrayVarUpdatedInLoopBody.kt")
public void testForInArrayWithArrayVarUpdatedInLoopBody() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInArrayWithArrayVarUpdatedInLoopBody.kt");
try {
doTest(fileName);
}
catch (Throwable ignore) {
return;
}
throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
}
@TestMetadata("forInRangeLiteralWithMixedTypeBounds.kt")
public void testForInRangeLiteralWithMixedTypeBounds() throws Exception {
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeLiteralWithMixedTypeBounds.kt");