org.jetbrains.kotlin.wasm.ir.Utils.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.wasm.ir
/**
* Calculate declaration IDs of linked wasm module
*/
fun WasmModule.calculateIds() {
fun List.calculateIds(startIndex: Int = 0) {
for ((index, field) in this.withIndex()) {
field.id = index + startIndex
}
}
functionTypes.calculateIds()
gcTypes.calculateIds(startIndex = functionTypes.size)
importedFunctions.calculateIds()
importedMemories.calculateIds()
importedTables.calculateIds()
importedGlobals.calculateIds()
importedTags.calculateIds()
elements.calculateIds()
definedFunctions.calculateIds(startIndex = importedFunctions.size)
globals.calculateIds(startIndex = importedGlobals.size)
memories.calculateIds(startIndex = importedMemories.size)
tables.calculateIds(startIndex = importedTables.size)
tags.calculateIds(startIndex = importedTags.size)
}
// This is used to perform simple peephole-like optimizations from the WasmExpressionBuilder.
// Takes two adjacent instructions and returns an array with 0, 1 or 2 instructions to replace the original ones.
// Returns null if no action is required.
fun foldWasmInstructions(prev: WasmInstr?, next: WasmInstr): List? {
if (prev == null)
return null
// Unreachable is not needed after another unreachable or return
if (next.operator == WasmOp.UNREACHABLE && prev.operator in listOf(WasmOp.UNREACHABLE, WasmOp.RETURN))
return listOf(prev)
if (next.operator == WasmOp.DROP) {
// simple pure instruction + drop -> nothing
if (prev.operator == WasmOp.GET_UNIT || prev.operator == WasmOp.REF_NULL)
return listOf()
// return + drop -> return
if (prev.operator == WasmOp.RETURN)
return listOf(prev)
}
return null
}