Optimize constant conditions
Using basic constant propagation (only integer constants, no arithmetic calculations), rewrite conditional jump instructions with constant arguments. This covers problem description in KT-17007. Note that it also works transparently with inline functions. Partial evaluation is required to cover more "advanced" cases. As a side effect, this also covers KT-3098: rewrite IF_ICMP<cmp_op>(x, 0) to IF<cmp0_op>(x).
This commit is contained in:
Dmitry Petrov
+187
@@ -0,0 +1,187 @@
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/*
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* Copyright 2010-2017 JetBrains s.r.o.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.jetbrains.kotlin.codegen.optimization
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import org.jetbrains.kotlin.codegen.optimization.common.OptimizationBasicInterpreter
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import org.jetbrains.kotlin.codegen.optimization.common.StrictBasicValue
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import org.jetbrains.kotlin.codegen.optimization.common.insnText
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import org.jetbrains.kotlin.codegen.optimization.fixStack.peek
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import org.jetbrains.kotlin.codegen.optimization.fixStack.top
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import org.jetbrains.kotlin.codegen.optimization.transformer.MethodTransformer
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import org.jetbrains.kotlin.utils.addToStdlib.cast
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import org.jetbrains.kotlin.utils.addToStdlib.safeAs
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import org.jetbrains.org.objectweb.asm.Opcodes
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import org.jetbrains.org.objectweb.asm.Type
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import org.jetbrains.org.objectweb.asm.tree.*
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import org.jetbrains.org.objectweb.asm.tree.analysis.BasicValue
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import org.jetbrains.org.objectweb.asm.tree.analysis.Frame
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class ConstantConditionEliminationMethodTransformer : MethodTransformer() {
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private val deadCodeElimination = DeadCodeEliminationMethodTransformer()
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override fun transform(internalClassName: String, methodNode: MethodNode) {
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do {
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val changes = ConstantConditionsOptimization(internalClassName, methodNode).run()
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if (changes) deadCodeElimination.transform(internalClassName, methodNode)
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} while (changes)
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}
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private class ConstantConditionsOptimization(val internalClassName: String, val methodNode: MethodNode) {
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fun run(): Boolean {
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val actions = collectRewriteActions()
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actions.forEach { it() }
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return actions.isNotEmpty()
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}
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private fun collectRewriteActions(): List<() -> Unit> =
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arrayListOf<() -> Unit>().also { actions ->
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val frames = analyze(internalClassName, methodNode, ConstantPropagationInterpreter())
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val insns = methodNode.instructions.toArray()
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for (i in frames.indices) {
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val frame = frames[i] ?: continue
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val insn = insns[i] as? JumpInsnNode ?: continue
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when (insn.opcode) {
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in Opcodes.IFEQ .. Opcodes.IFLE ->
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tryRewriteComparisonWithZero(insn, frame, actions)
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in Opcodes.IF_ICMPEQ .. Opcodes.IF_ICMPLE ->
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tryRewriteBinaryComparison(insn, frame, actions)
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}
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}
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}
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private fun tryRewriteComparisonWithZero(insn: JumpInsnNode, frame: Frame<BasicValue>, actions: ArrayList<() -> Unit>) {
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val top = frame.top()!!.safeAs<IConstValue>() ?: return
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val constCondition = when (insn.opcode) {
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Opcodes.IFEQ -> top.value == 0
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Opcodes.IFNE -> top.value != 0
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Opcodes.IFGE -> top.value >= 0
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Opcodes.IFGT -> top.value > 0
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Opcodes.IFLE -> top.value <= 0
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Opcodes.IFLT -> top.value < 0
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else -> throw AssertionError("Unexpected instruction: ${insn.insnText}")
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}
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actions.add {
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methodNode.instructions.run {
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insertBefore(insn, InsnNode(Opcodes.POP))
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if (constCondition)
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set(insn, JumpInsnNode(Opcodes.GOTO, insn.label))
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else
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remove(insn)
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}
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}
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}
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private fun tryRewriteBinaryComparison(insn: JumpInsnNode, frame: Frame<BasicValue>, actions: ArrayList<() -> Unit>) {
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val arg1 = frame.peek(1)!!
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val arg2 = frame.peek(0)!!
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if (arg1 is IConstValue && arg2 is IConstValue) {
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rewriteBinaryComparisonOfConsts(insn, arg1.value, arg2.value, actions)
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}
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else if (arg2 is IConstValue && arg2.value == 0) {
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rewriteBinaryComparisonWith0(insn, actions)
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}
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}
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private fun rewriteBinaryComparisonOfConsts(insn: JumpInsnNode, value1: Int, value2: Int, actions: ArrayList<() -> Unit>) {
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val constCondition = when (insn.opcode) {
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Opcodes.IF_ICMPEQ -> value1 == value2
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Opcodes.IF_ICMPNE -> value1 != value2
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Opcodes.IF_ICMPLE -> value1 <= value2
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Opcodes.IF_ICMPLT -> value1 < value2
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Opcodes.IF_ICMPGE -> value1 >= value2
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Opcodes.IF_ICMPGT -> value1 > value2
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else -> throw AssertionError("Unexpected instruction: ${insn.insnText}")
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}
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actions.add {
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methodNode.instructions.run {
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insertBefore(insn, InsnNode(Opcodes.POP))
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insertBefore(insn, InsnNode(Opcodes.POP))
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if (constCondition)
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set(insn, JumpInsnNode(Opcodes.GOTO, insn.label))
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else
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remove(insn)
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}
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}
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}
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private fun rewriteBinaryComparisonWith0(insn: JumpInsnNode, actions: ArrayList<() -> Unit>) {
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actions.add {
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methodNode.instructions.run {
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insertBefore(insn, InsnNode(Opcodes.POP))
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val cmpWith0Opcode = when (insn.opcode) {
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Opcodes.IF_ICMPEQ -> Opcodes.IFEQ
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Opcodes.IF_ICMPNE -> Opcodes.IFNE
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Opcodes.IF_ICMPLE -> Opcodes.IFLE
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Opcodes.IF_ICMPLT -> Opcodes.IFLT
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Opcodes.IF_ICMPGE -> Opcodes.IFGE
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Opcodes.IF_ICMPGT -> Opcodes.IFGT
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else -> throw AssertionError("Unexpected instruction: ${insn.insnText}")
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}
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set(insn, JumpInsnNode(cmpWith0Opcode, insn.label))
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}
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}
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}
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}
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private class IConstValue private constructor(val value: Int) : StrictBasicValue(Type.INT_TYPE) {
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override fun equals(other: Any?): Boolean =
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other === this ||
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other is IConstValue && other.value == this.value
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override fun hashCode(): Int = value
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override fun toString(): String = "IConst($value)"
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companion object {
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private val ICONST_CACHE = Array(7) { IConstValue(it - 1) }
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fun of(value: Int) =
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if (value in -1 .. 5)
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ICONST_CACHE[value + 1]
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else
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IConstValue(value)
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}
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}
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private class ConstantPropagationInterpreter : OptimizationBasicInterpreter() {
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override fun newOperation(insn: AbstractInsnNode): BasicValue =
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when (insn.opcode) {
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in Opcodes.ICONST_M1 .. Opcodes.ICONST_5 ->
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IConstValue.of(insn.opcode - Opcodes.ICONST_0)
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Opcodes.BIPUSH, Opcodes.SIPUSH ->
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IConstValue.of(insn.cast<IntInsnNode>().operand)
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Opcodes.LDC -> {
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val operand = insn.cast<LdcInsnNode>().cst
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if (operand is Int)
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IConstValue.of(operand)
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else
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super.newOperation(insn)
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}
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else -> super.newOperation(insn)
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}
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override fun merge(v: BasicValue, w: BasicValue): BasicValue =
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if (v is IConstValue && w is IConstValue && v == w)
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v
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else
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super.merge(v, w)
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}
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}
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+1
@@ -52,6 +52,7 @@ class OptimizationMethodVisitor(
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CapturedVarsOptimizationMethodTransformer(),
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RedundantNullCheckMethodTransformer(),
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RedundantCheckCastEliminationMethodTransformer(),
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ConstantConditionEliminationMethodTransformer(),
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RedundantBoxingMethodTransformer(),
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RedundantCoercionToUnitTransformer(),
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DeadCodeEliminationMethodTransformer(),
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+24
-6
@@ -16,6 +16,7 @@
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package org.jetbrains.kotlin.codegen.optimization.boxing
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import org.jetbrains.kotlin.codegen.optimization.common.isLoadOperation
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import org.jetbrains.kotlin.codegen.optimization.common.isMeaningful
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import org.jetbrains.kotlin.codegen.optimization.fixStack.top
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import org.jetbrains.kotlin.codegen.optimization.removeNodeGetNext
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@@ -63,7 +64,7 @@ class RedundantCoercionToUnitTransformer : MethodTransformer() {
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private val frames by lazy { analyzeMethodBody() }
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fun transform() {
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if (!insns.any { it.isUnitInstanceOrNull() }) return
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if (!insns.any { it.isPurePush() }) return
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computeTransformations()
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for ((insn, transformation) in transformations.entries) {
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@@ -87,7 +88,7 @@ class RedundantCoercionToUnitTransformer : MethodTransformer() {
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}
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override fun unaryOperation(insn: AbstractInsnNode, value: SourceValue): SourceValue {
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if (insn.opcode != Opcodes.CHECKCAST) {
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if (insn.opcode != Opcodes.CHECKCAST && !insn.isPrimitiveTypeConversion()) {
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value.insns.markAsDontTouch()
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}
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return super.unaryOperation(insn, value)
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@@ -158,10 +159,22 @@ class RedundantCoercionToUnitTransformer : MethodTransformer() {
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transformations[insn] = replaceWithPopTransformation(boxedValueSize)
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}
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insn.isUnitInstanceOrNull() -> {
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insn.isPurePush() -> {
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transformations[insn] = replaceWithNopTransformation()
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}
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insn.isPrimitiveTypeConversion() -> {
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val inputTop = getInputTop(insn)
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val sources = inputTop.insns
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if (sources.all { !isDontTouch(it) }) {
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transformations[insn] = replaceWithNopTransformation()
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sources.forEach { propagatePopBackwards(it, inputTop.size) }
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}
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else {
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transformations[insn] = replaceWithPopTransformation(poppedValueSize)
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}
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}
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else -> {
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transformations[insn] = insertPopAfterTransformation(poppedValueSize)
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}
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@@ -232,7 +245,7 @@ class RedundantCoercionToUnitTransformer : MethodTransformer() {
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it.isPrimitiveBoxing() && (it as MethodInsnNode).owner == resultType
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private fun isTransformablePopOperand(insn: AbstractInsnNode) =
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insn.opcode == Opcodes.CHECKCAST || insn.isPrimitiveBoxing() || insn.isUnitInstanceOrNull()
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insn.opcode == Opcodes.CHECKCAST || insn.isPrimitiveBoxing() || insn.isPurePush()
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private fun isDontTouch(insn: AbstractInsnNode) =
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dontTouchInsnIndices[insnList.indexOf(insn)]
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@@ -240,9 +253,14 @@ class RedundantCoercionToUnitTransformer : MethodTransformer() {
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}
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fun AbstractInsnNode.isUnitInstanceOrNull() =
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opcode == Opcodes.ACONST_NULL || isUnitInstance()
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fun AbstractInsnNode.isPurePush() =
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isLoadOperation() ||
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opcode in Opcodes.ACONST_NULL .. Opcodes.LDC + 2 ||
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isUnitInstance()
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fun AbstractInsnNode.isUnitInstance() =
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opcode == Opcodes.GETSTATIC &&
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this is FieldInsnNode && owner == "kotlin/Unit" && name == "INSTANCE"
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fun AbstractInsnNode.isPrimitiveTypeConversion() =
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opcode in Opcodes.I2L .. Opcodes.I2S
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@@ -0,0 +1,25 @@
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// FILE: util.kt
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inline fun ieq(x: Int, y: Int) = x == y
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inline fun ine(x: Int, y: Int) = x != y
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inline fun ilt(x: Int, y: Int) = x < y
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inline fun ile(x: Int, y: Int) = x <= y
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inline fun igt(x: Int, y: Int) = x > y
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inline fun ige(x: Int, y: Int) = x >= y
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// FILE: test.kt
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fun testeq(x: Int) = ieq(x, 0)
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fun testne(x: Int) = ine(x, 0)
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fun testlt(x: Int) = ilt(x, 0)
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fun testle(x: Int) = ile(x, 0)
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fun testgt(x: Int) = igt(x, 0)
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fun testge(x: Int) = ige(x, 0)
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// @TestKt.class:
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// 0 IF_ICMPEQ
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// 0 IF_ICMPNE
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// 0 IF_ICMPGE
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// 0 IF_ICMPGT
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// 0 IF_ICMPLE
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// 0 IF_ICMPLT
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@@ -0,0 +1,35 @@
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// FILE: util.kt
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const val FLAG = true
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const val OTHER_FLAG = false
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fun doStuff1() {}
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fun doStuff2() {}
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fun doStuff3() {}
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inline fun doStuff1IfTrue(flag: Boolean) {
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if (flag) doStuff1()
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}
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inline fun doStuff2IfFalse(flag: Boolean) {
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if (!flag) doStuff2()
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}
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inline fun doStuff3IfComplex(flag: Boolean) {
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if (flag && !OTHER_FLAG) doStuff3()
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}
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// FILE: test.kt
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fun test() {
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doStuff1IfTrue(FLAG)
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doStuff2IfFalse(FLAG)
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doStuff3IfComplex(FLAG)
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}
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// @TestKt.class:
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// 0 FLAG
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// 1 INVOKESTATIC UtilKt.doStuff1
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// 0 INVOKESTATIC UtilKt.doStuff2
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// 1 INVOKESTATIC UtilKt.doStuff3
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// 0 ILOAD 0
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// 0 IFEQ
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// 0 IFNE
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@@ -0,0 +1,58 @@
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// FILE: util.kt
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const val MAGIC = 42
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fun doStuffEq() {}
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fun doStuffNotEq() {}
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fun doStuffLt() {}
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fun doStuffLe() {}
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fun doStuffGt() {}
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fun doStuffGe() {}
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inline fun doStuffIfEq(i: Int) {
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if (i == MAGIC) doStuffEq()
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}
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inline fun doStuffIfNotEq(i: Int) {
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if (i != MAGIC) doStuffNotEq()
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}
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inline fun doStuffIfLt(i: Int) {
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if (i < MAGIC) doStuffLt()
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}
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inline fun doStuffIfLe(i: Int) {
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if (i <= MAGIC) doStuffLe()
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}
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inline fun doStuffIfGt(i: Int) {
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if (i > MAGIC) doStuffGt()
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}
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inline fun doStuffIfGe(i: Int) {
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if (i >= MAGIC) doStuffGe()
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}
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// FILE: test.kt
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fun test() {
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doStuffIfEq(100)
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doStuffIfNotEq(100)
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doStuffIfLt(100)
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doStuffIfLe(100)
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doStuffIfGt(100)
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doStuffIfGe(100)
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}
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// @TestKt.class:
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// 0 INVOKESTATIC UtilKt.doStuffEq
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// 1 INVOKESTATIC UtilKt.doStuffNotEq
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// 0 INVOKESTATIC UtilKt.doStuffLt
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// 0 INVOKESTATIC UtilKt.doStuffLe
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// 1 INVOKESTATIC UtilKt.doStuffGt
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// 1 INVOKESTATIC UtilKt.doStuffGe
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// 0 ILOAD 0
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// 0 IFEQ
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// 0 IFNE
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||||
// 0 IFLT
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// 0 IFLE
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// 0 IFGE
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// 0 IFGT
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@@ -0,0 +1,9 @@
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fun testLt(x: String, y: String) = x < y
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fun testLe(x: String, y: String) = x <= y
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fun testGt(x: String, y: String) = x > y
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fun testGe(x: String, y: String) = x >= y
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// 0 IF_ICMPGE
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||||
// 0 IF_ICMPGT
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// 0 IF_ICMPLE
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// 0 IF_ICMPLT
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@@ -885,6 +885,39 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
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}
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}
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@TestMetadata("compiler/testData/codegen/bytecodeText/constantConditions")
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@TestDataPath("$PROJECT_ROOT")
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@RunWith(JUnit3RunnerWithInners.class)
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public static class ConstantConditions extends AbstractBytecodeTextTest {
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public void testAllFilesPresentInConstantConditions() throws Exception {
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KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/bytecodeText/constantConditions"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.ANY, true);
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}
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||||
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@TestMetadata("cmpIntWith0.kt")
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public void testCmpIntWith0() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/constantConditions/cmpIntWith0.kt");
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doTest(fileName);
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||||
}
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||||
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@TestMetadata("constantFlag.kt")
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public void testConstantFlag() throws Exception {
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String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/constantConditions/constantFlag.kt");
|
||||
doTest(fileName);
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||||
}
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||||
|
||||
@TestMetadata("constantInt.kt")
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||||
public void testConstantInt() throws Exception {
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||||
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/constantConditions/constantInt.kt");
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doTest(fileName);
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||||
}
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||||
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||||
@TestMetadata("kt3098.kt")
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||||
public void testKt3098() throws Exception {
|
||||
String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/constantConditions/kt3098.kt");
|
||||
doTest(fileName);
|
||||
}
|
||||
}
|
||||
|
||||
@TestMetadata("compiler/testData/codegen/bytecodeText/constants")
|
||||
@TestDataPath("$PROJECT_ROOT")
|
||||
@RunWith(JUnit3RunnerWithInners.class)
|
||||
|
||||
Reference in New Issue
Block a user