[Wasm] Improve interface method dispatch

- Use typed Wasm tables for each interface method to avoid runtime
  function type check

- Use linear search by implemented interface rather than by individual
  virtual function signature

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt

@@ -126,7 +126,7 @@ class WasmSymbols(
     val wasmInterfaceId = getInternalFunction("wasmInterfaceId")
 
     val getVirtualMethodId = getInternalFunction("getVirtualMethodId")
-    val getInterfaceMethodId = getInternalFunction("getInterfaceMethodId")
+    val getInterfaceImplId = getInternalFunction("getInterfaceImplId")
 
     val isSubClass = getInternalFunction("isSubClass")
     val isInterface = getInternalFunction("isInterface")

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.backend.common.ir.isOverridable
 import org.jetbrains.kotlin.backend.common.ir.returnType
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
 import org.jetbrains.kotlin.backend.wasm.WasmSymbols
-import org.jetbrains.kotlin.backend.wasm.lower.wasmSignature
 import org.jetbrains.kotlin.backend.wasm.utils.*
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
@@ -219,16 +218,19 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
                 generateExpression(call.dispatchReceiver!!)
                 body.buildConstI32(vfSlot)
                 body.buildCall(context.referenceFunction(wasmSymbols.getVirtualMethodId))
+                body.buildCallIndirect(
+                    symbol = context.referenceFunctionType(function.symbol)
+                )
             } else {
-                val signatureId = context.referenceSignatureId(function.wasmSignature(backendContext.irBuiltIns))
                 generateExpression(call.dispatchReceiver!!)
-                body.buildConstI32Symbol(signatureId)
+                body.buildConstI32Symbol(context.referenceInterfaceId(klass.symbol))
-                body.buildCall(context.referenceFunction(wasmSymbols.getInterfaceMethodId))
+                body.buildCall(context.referenceFunction(wasmSymbols.getInterfaceImplId))
+                body.buildCallIndirect(
+                    tableIdx = WasmSymbolIntWrapper(context.referenceInterfaceTable(function.symbol)),
+                    symbol = context.referenceFunctionType(function.symbol)
+                )
             }
 
-            body.buildCallIndirect(
-                symbol = context.referenceFunctionType(function.symbol)
-            )
         } else {
             // Static function call
             body.buildCall(context.referenceFunction(function.symbol))

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/ClassInfo.kt

@@ -8,6 +8,8 @@ package org.jetbrains.kotlin.backend.wasm.ir2wasm
 import org.jetbrains.kotlin.backend.common.ir.isOverridableOrOverrides
 import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
 import org.jetbrains.kotlin.backend.wasm.lower.wasmSignature
+import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
+import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.ir.backend.js.utils.realOverrideTarget
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -78,6 +80,23 @@ class ClassMetadata(
         virtualMethods.map { it.signature }.toSet()
 }
 
+class InterfaceMetadata(
+    val iface: IrClass,
+    irBuiltIns: IrBuiltIns
+) {
+    val methods: List<VirtualMethodMetadata> =
+        iface.declarations
+            .filterIsInstance<IrSimpleFunction>()
+            .filter { !it.isFakeOverride && it.visibility != DescriptorVisibilities.PRIVATE && it.modality != Modality.FINAL }
+            .map {
+                VirtualMethodMetadata(
+                    it,
+                    it.wasmSignature(irBuiltIns)
+                )
+            }
+}
+
+
 class VirtualMethodMetadata(
     val function: IrSimpleFunction,
     val signature: WasmSignature

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
+import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
@@ -186,6 +187,14 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
         }
 
         if (declaration.isInterface) {
+            val metadata = InterfaceMetadata(declaration, irBuiltIns)
+            for (method in metadata.methods) {
+                val methodSymbol = method.function.symbol
+                val table = WasmTable(
+                    elementType = WasmRefNullType(WasmHeapType.Type(context.referenceFunctionType(methodSymbol)))
+                )
+                context.defineInterfaceMethodTable(methodSymbol, table)
+            }
             context.registerInterface(symbol)
         } else {
             val nameStr = declaration.fqNameWhenAvailable.toString()
@@ -235,6 +244,28 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
             context.defineRTT(symbol, rtt)
             context.registerClass(symbol)
             context.generateTypeInfo(symbol, binaryDataStruct(metadata))
+
+            // New type info model
+            if (declaration.modality != Modality.ABSTRACT) {
+                context.generateInterfaceTable(symbol, interfaceTable(metadata))
+                for (i in metadata.interfaces) {
+                    val interfaceImplementation = InterfaceImplementation(i.symbol, declaration.symbol)
+                    // TODO: Cache it
+                    val interfaceMetadata = InterfaceMetadata(i, irBuiltIns)
+                    val table = interfaceMetadata.methods.associate { method ->
+                        val classMethod: VirtualMethodMetadata =
+                            metadata.virtualMethods
+                                .find { it.signature == method.signature }  // TODO: Use map
+                                ?: error("Cannot find class implementation of method ${method.signature} in class ${declaration.fqNameWhenAvailable}")
+
+                        method.function.symbol as IrFunctionSymbol to context.referenceFunction(classMethod.function.symbol)
+                    }
+                    context.registerInterfaceImplementationMethod(
+                        interfaceImplementation,
+                        table
+                    )
+                }
+            }
         }
 
         for (member in declaration.declarations) {
@@ -252,20 +283,6 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
         val superTypeField =
             ConstantDataIntField("Super class", superClassSymbol)
 
-        val interfacesArray = ConstantDataIntArray(
-            "data",
-            classMetadata.interfaces.map { context.referenceInterfaceId(it.symbol) }
-        )
-        val interfacesArraySize = ConstantDataIntField(
-            "size",
-            interfacesArray.value.size
-        )
-
-        val implementedInterfacesArrayWithSize = ConstantDataStruct(
-            "Implemented interfaces array",
-            listOf(interfacesArraySize, interfacesArray)
-        )
-
         val vtableSizeField = ConstantDataIntField(
             "V-table length",
             classMetadata.virtualMethods.size
@@ -282,29 +299,48 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
             }
         )
 
-        val signaturesArray = ConstantDataIntArray(
+        val interfaceTablePtr = ConstantDataIntField(
-            "Signatures",
+            "interfaceTablePtr",
-            classMetadata.virtualMethods.map {
+            context.referenceInterfaceTableAddress(classMetadata.klass.symbol)
-                if (it.function.modality == Modality.ABSTRACT) {
-                    WasmSymbol(invalidIndex)
-                } else {
-                    context.referenceSignatureId(it.signature)
-                }
-            }
         )
 
         return ConstantDataStruct(
             "Class TypeInfo: ${classMetadata.klass.fqNameWhenAvailable} ",
             listOf(
                 superTypeField,
+                interfaceTablePtr,
                 vtableSizeField,
                 vtableArray,
-                signaturesArray,
-                implementedInterfacesArrayWithSize,
             )
         )
     }
 
+
+    private fun interfaceTable(classMetadata: ClassMetadata): ConstantDataStruct {
+        val interfaces = classMetadata.interfaces
+        val size = ConstantDataIntField("size", interfaces.size)
+        val interfaceIds = ConstantDataIntArray(
+            "interfaceIds",
+            interfaces.map { context.referenceInterfaceId(it.symbol) },
+        )
+        val interfaceImplementationIds = ConstantDataIntArray(
+            "interfaceImplementationId",
+            interfaces.map {
+                context.referenceInterfaceImplementationId(InterfaceImplementation(it.symbol, classMetadata.klass.symbol))
+            },
+        )
+
+        return ConstantDataStruct(
+            "Class interface table: ${classMetadata.klass.fqNameWhenAvailable} ",
+            listOf(
+                size,
+                interfaceIds,
+                interfaceImplementationIds,
+            )
+        )
+    }
+
+
     override fun visitField(declaration: IrField) {
         // Member fields are generated as part of struct type
         if (!declaration.isStatic) return

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/WasmBaseCodegenContext.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
-import org.jetbrains.kotlin.wasm.ir.*
 import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
@@ -15,6 +14,7 @@ import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.wasm.ir.*
 
 interface WasmBaseCodegenContext {
     val backendContext: WasmBackendContext
@@ -31,6 +31,8 @@ interface WasmBaseCodegenContext {
 
     fun referenceSignatureId(signature: WasmSignature): WasmSymbol<Int>
 
+    fun referenceInterfaceTable(irFunction: IrFunctionSymbol): WasmSymbol<WasmTable>
+
     fun referenceStringLiteral(string: String): WasmSymbol<Int>
 
     fun transformType(irType: IrType): WasmType

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/WasmCompiledModuleFragment.kt

@@ -5,13 +5,13 @@
 
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
-import org.jetbrains.kotlin.wasm.ir.*
 import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithName
 import org.jetbrains.kotlin.ir.declarations.IrExternalPackageFragment
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
 import org.jetbrains.kotlin.ir.util.getPackageFragment
+import org.jetbrains.kotlin.wasm.ir.*
 
 class WasmCompiledModuleFragment {
     val functions =
@@ -44,6 +44,27 @@ class WasmCompiledModuleFragment {
 
     val typeInfo =
         ReferencableAndDefinable<IrClassSymbol, ConstantDataElement>()
+
+    // Wasm table for each method of each interface.
+    val interfaceMethodTables =
+        ReferencableAndDefinable<IrFunctionSymbol, WasmTable>()
+
+    // Defined class interface tables
+    val definedClassITableData =
+        ReferencableAndDefinable<IrClassSymbol, ConstantDataElement>()
+
+    // Address of class interface table in linear memory
+    val referencedClassITableAddresses =
+        ReferencableElements<IrClassSymbol, Int>()
+
+    // Sequential number of an implementation (class, object, etc.) for a particular interface
+    // Used as index in table for interface method dispatch
+    val referencedInterfaceImplementationId =
+        ReferencableElements<InterfaceImplementation, Int>()
+
+    val interfaceImplementationsMethods =
+        LinkedHashMap<InterfaceImplementation, Map<IrFunctionSymbol, WasmSymbol<WasmFunction>>>()
+
     val exports = mutableListOf<WasmExport<*>>()
 
     class JsCodeSnippet(val importName: String, val jsCode: String)
@@ -92,27 +113,42 @@ class WasmCompiledModuleFragment {
         bind(runtimeTypes.unbound, runtimeTypes.defined)
 
         val klassIds = mutableMapOf<IrClassSymbol, Int>()
-        var classId = 0
+        var currentDataSectionAddress = 0
         for (typeInfoElement in typeInfo.elements) {
             val ir = typeInfo.wasmToIr.getValue(typeInfoElement)
-            klassIds[ir] = classId
+            klassIds[ir] = currentDataSectionAddress
-            classId += typeInfoElement.sizeInBytes
+            currentDataSectionAddress += typeInfoElement.sizeInBytes
+        }
+
+        val interfaceTableAddresses = mutableMapOf<IrClassSymbol, Int>()
+        for (typeInfoElement in definedClassITableData.elements) {
+            val ir = definedClassITableData.wasmToIr.getValue(typeInfoElement)
+            interfaceTableAddresses[ir] = currentDataSectionAddress
+            currentDataSectionAddress += typeInfoElement.sizeInBytes
         }
 
         bind(classIds.unbound, klassIds)
+        bind(referencedClassITableAddresses.unbound, interfaceTableAddresses)
         bindIndices(virtualFunctionId.unbound, virtualFunctions)
         bindIndices(signatureId.unbound, signatures.toList())
         bindIndices(interfaceId.unbound, interfaces)
         bindIndices(stringLiteralId.unbound, stringLiterals)
 
-        val data = typeInfo.elements.map {
+        val interfaceImplementationIds = mutableMapOf<InterfaceImplementation, Int>()
-            val ir = typeInfo.wasmToIr.getValue(it)
+        val numberOfInterfaceImpls = mutableMapOf<IrClassSymbol, Int>()
-            val id = klassIds.getValue(ir)
+        for (interfaceImplementation in interfaceImplementationsMethods.keys) {
-            val offset = mutableListOf<WasmInstr>()
+            val prev = numberOfInterfaceImpls.getOrPut(interfaceImplementation.irInterface) { 0 }
-            WasmIrExpressionBuilder(offset).buildConstI32(id)
+            interfaceImplementationIds[interfaceImplementation] = prev
-            WasmData(WasmDataMode.Active(0, offset), it.toBytes())
+            numberOfInterfaceImpls[interfaceImplementation.irInterface] = prev + 1
         }
 
+        bind(referencedInterfaceImplementationId.unbound, interfaceImplementationIds)
+        bind(interfaceMethodTables.unbound, interfaceMethodTables.defined)
+
+        val data =
+            typeInfo.buildData(address = { klassIds.getValue(it) }) +
+                    definedClassITableData.buildData(address = { interfaceTableAddresses.getValue(it) })
+
         val logTypeInfo = false
         if (logTypeInfo) {
             println("Signatures: ")
@@ -151,7 +187,38 @@ class WasmCompiledModuleFragment {
             WasmElement.Mode.Active(table, offsetExpr)
         )
 
-        val typeInfoSize = classId
+        val interfaceTableElementsLists = interfaceMethodTables.defined.keys.associateWith {
+            mutableMapOf<Int, WasmSymbol<WasmFunction>>()
+        }
+
+        interfaceImplementationIds.forEach { ii: InterfaceImplementation, implId: Int ->
+            for ((interfaceFunction: IrFunctionSymbol, wasmFunction: WasmSymbol<WasmFunction>) in interfaceImplementationsMethods[ii]!!) {
+                interfaceTableElementsLists[interfaceFunction]!![implId] = wasmFunction
+            }
+        }
+
+        val interfaceTableElements = interfaceTableElementsLists.map { (interfaceFunction, methods) ->
+            val type = interfaceMethodTables.defined[interfaceFunction]!!.elementType
+            val functions = MutableList(methods.size) { idx ->
+                val wasmFunc = methods[idx]!!
+                val expression = buildWasmExpression {
+                    buildInstr(WasmOp.REF_FUNC, WasmImmediate.FuncIdx(wasmFunc))
+                }
+                WasmTable.Value.Expression(expression)
+            }
+            WasmElement(
+                type,
+                values = functions,
+                WasmElement.Mode.Active(interfaceMethodTables.defined[interfaceFunction]!!, offsetExpr)
+            )
+        }
+
+        interfaceMethodTables.defined.forEach { (function, table) ->
+            val size = interfaceTableElementsLists[function]!!.size.toUInt()
+            table.limits = WasmLimits(size, size)
+        }
+
+        val typeInfoSize = currentDataSectionAddress
         val memorySizeInPages = (typeInfoSize / 65_536) + 1
         val memory = WasmMemory(WasmLimits(memorySizeInPages.toUInt(), memorySizeInPages.toUInt()))
 
@@ -166,12 +233,12 @@ class WasmCompiledModuleFragment {
             importsInOrder = importedFunctions,
             importedFunctions = importedFunctions,
             definedFunctions = functions.elements.filterIsInstance<WasmFunction.Defined>(),
-            tables = listOf(table),
+            tables = listOf(table) + interfaceMethodTables.elements,
             memories = listOf(memory),
             globals = globals.elements + sortedRttGlobals,
             exports = exports,
             startFunction = startFunction!!,
-            elements = listOf(elements),
+            elements = listOf(elements) + interfaceTableElements,
             data = data
         )
         module.calculateIds()
@@ -208,3 +275,18 @@ fun <IrSymbolType> bindIndices(
         wasmSymbol.bind(index)
     }
 }
+
+inline fun WasmCompiledModuleFragment.ReferencableAndDefinable<IrClassSymbol, ConstantDataElement>.buildData(address: (IrClassSymbol) -> Int): List<WasmData> {
+    return elements.map {
+        val id = address(wasmToIr.getValue(it))
+        val offset = mutableListOf<WasmInstr>()
+        WasmIrExpressionBuilder(offset).buildConstI32(id)
+        WasmData(WasmDataMode.Active(0, offset), it.toBytes())
+    }
+}
+
+
+data class InterfaceImplementation(
+    val irInterface: IrClassSymbol,
+    val irClass: IrClassSymbol
+)

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/WasmModuleCodegenContext.kt

@@ -5,13 +5,11 @@
 
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
-import org.jetbrains.kotlin.wasm.ir.*
-import org.jetbrains.kotlin.backend.wasm.ir2wasm.ConstantDataElement
-import org.jetbrains.kotlin.backend.wasm.ir2wasm.WasmBaseCodegenContext
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
+import org.jetbrains.kotlin.wasm.ir.*
 
 /**
  * Interface for generating WebAssembly module.
@@ -22,6 +20,7 @@ interface WasmModuleCodegenContext : WasmBaseCodegenContext {
     fun defineGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration)
     fun defineRTT(irClass: IrClassSymbol, wasmGlobal: WasmGlobal)
     fun defineFunctionType(irFunction: IrFunctionSymbol, wasmFunctionType: WasmFunctionType)
+    fun defineInterfaceMethodTable(irFunction: IrFunctionSymbol, wasmTable: WasmTable)
     fun addJsFun(importName: String, jsCode: String)
 
     fun setStartFunction(wasmFunction: WasmFunction)
@@ -32,4 +31,13 @@ interface WasmModuleCodegenContext : WasmBaseCodegenContext {
     fun registerClass(irClass: IrClassSymbol)
 
     fun generateTypeInfo(irClass: IrClassSymbol, typeInfo: ConstantDataElement)
+    fun generateInterfaceTable(irClass: IrClassSymbol, table: ConstantDataElement)
+
+    fun registerInterfaceImplementationMethod(
+        interfaceImplementation: InterfaceImplementation,
+        table: Map<IrFunctionSymbol, WasmSymbol<WasmFunction>>,
+    )
+
+    fun referenceInterfaceImplementationId(interfaceImplementation: InterfaceImplementation): WasmSymbol<Int>
+    fun referenceInterfaceTableAddress(irClass: IrClassSymbol): WasmSymbol<Int>
 }

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/WasmModuleCodegenContextImpl.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
-import org.jetbrains.kotlin.wasm.ir.*
 import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.ir.declarations.IrField
@@ -20,6 +19,7 @@ import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.types.isNothing
 import org.jetbrains.kotlin.ir.util.isFunction
 import org.jetbrains.kotlin.ir.util.parentAsClass
+import org.jetbrains.kotlin.wasm.ir.*
 
 
 class WasmModuleCodegenContextImpl(
@@ -68,6 +68,10 @@ class WasmModuleCodegenContextImpl(
         wasmFragment.typeInfo.define(irClass, typeInfo)
     }
 
+    override fun generateInterfaceTable(irClass: IrClassSymbol, table: ConstantDataElement) {
+        wasmFragment.definedClassITableData.define(irClass, table)
+    }
+
     override fun setStartFunction(wasmFunction: WasmFunction) {
         wasmFragment.startFunction = wasmFunction
     }
@@ -108,6 +112,23 @@ class WasmModuleCodegenContextImpl(
         wasmFragment.functionTypes.define(irFunction, wasmFunctionType)
     }
 
+    override fun defineInterfaceMethodTable(irFunction: IrFunctionSymbol, wasmTable: WasmTable) {
+        wasmFragment.interfaceMethodTables.define(irFunction, wasmTable)
+    }
+
+    override fun referenceInterfaceImplementationId(
+        interfaceImplementation: InterfaceImplementation
+    ): WasmSymbol<Int> =
+        wasmFragment.referencedInterfaceImplementationId.reference(interfaceImplementation)
+
+
+    override fun registerInterfaceImplementationMethod(
+        interfaceImplementation: InterfaceImplementation,
+        table: Map<IrFunctionSymbol, WasmSymbol<WasmFunction>>
+    ) {
+        wasmFragment.interfaceImplementationsMethods[interfaceImplementation] = table
+    }
+
     private val classMetadataCache = mutableMapOf<IrClassSymbol, ClassMetadata>()
     override fun getClassMetadata(irClass: IrClassSymbol): ClassMetadata =
         classMetadataCache.getOrPut(irClass) {
@@ -143,6 +164,12 @@ class WasmModuleCodegenContextImpl(
     override fun referenceClassId(irClass: IrClassSymbol): WasmSymbol<Int> =
         wasmFragment.classIds.reference(irClass)
 
+    override fun referenceInterfaceTableAddress(irClass: IrClassSymbol): WasmSymbol<Int> {
+        if (irClass.owner.modality == Modality.ABSTRACT) return WasmSymbol(-1)
+        return wasmFragment.referencedClassITableAddresses.reference(irClass)
+    }
+
+
     override fun referenceInterfaceId(irInterface: IrClassSymbol): WasmSymbol<Int> {
         // HACK to substitute kotlin.Function5 with kotlin.wasm.internal.Function5
         val defaultType = irInterface.defaultType
@@ -164,6 +191,10 @@ class WasmModuleCodegenContextImpl(
         return wasmFragment.signatureId.reference(signature)
     }
 
+    override fun referenceInterfaceTable(irFunction: IrFunctionSymbol): WasmSymbol<WasmTable> {
+        return wasmFragment.interfaceMethodTables.reference(irFunction)
+    }
+
     override fun getStructFieldRef(field: IrField): WasmSymbol<Int> {
         val klass = field.parentAsClass
         val metadata = getClassMetadata(klass.symbol)

compiler/testData/codegen/box/callableReference/function/local/enumExtendsTrait.kt

@@ -1,3 +1,6 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: IMPLICIT_INTERFACE_METHOD_IMPL
+
 interface Named {
     val name: String
 }

compiler/testData/codegen/box/funInterface/basicFunInterfaceConversion.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 
 fun interface Foo {

compiler/testData/codegen/box/funInterface/funConversionInVararg.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument
 
 fun interface MyRunnable {

compiler/testData/codegen/box/funInterface/noOptimizedCallableReferences.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // KOTLIN_CONFIGURATION_FLAGS: +JVM.NO_OPTIMIZED_CALLABLE_REFERENCES
 
 fun interface P {

compiler/testData/codegen/box/funInterface/partialSam.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // WITH_RUNTIME
 

compiler/testData/codegen/box/funInterface/primitiveConversions.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 
 // This test should check argument coercion between the SAM and the lambda.

compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // WITH_RUNTIME
 

compiler/testData/codegen/box/funInterface/samConstructorExplicitInvocation.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +FunctionalInterfaceConversion
 
 fun interface S {

compiler/testData/codegen/box/funInterface/samConversionToGenericInterfaceInGenericFun.kt

@@ -1,3 +1,6 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
+
 fun interface FunIFace<T, R> {
     fun call(ic: T): R
 }

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/any.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 
 fun <T> underlying(a: IC): T = bar(a) {

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/anyN.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 
 fun <T> underlying(a: IC): T = bar(a) {

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/iface.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 
 fun <T> underlying(a: IC): T = bar(a) {

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/ifaceChild.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 
 fun <T> underlying(a: IC): T = bar(a) {

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/primitive.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 
 fun <T> underlying(a: IC): T = bar(a) {

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/result.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 // WITH_RUNTIME
 

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/string.kt

@@ -1,3 +1,5 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
 // !LANGUAGE: +InlineClasses
 
 fun <T> underlying(a: IC): T = bar(a) {

compiler/testData/codegen/box/regressions/kt4142.kt

@@ -1,3 +1,6 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: IMPLICIT_INTERFACE_METHOD_IMPL
+
 open class B {
     val name: String
         get() = "OK"

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java

@@ -1631,11 +1631,6 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
                     runTest("compiler/testData/codegen/box/callableReference/function/local/constructorWithInitializer.kt");
                 }
 
-                @TestMetadata("enumExtendsTrait.kt")
-                public void testEnumExtendsTrait() throws Exception {
-                    runTest("compiler/testData/codegen/box/callableReference/function/local/enumExtendsTrait.kt");
-                }
-
                 @TestMetadata("extension.kt")
                 public void testExtension() throws Exception {
                     runTest("compiler/testData/codegen/box/callableReference/function/local/extension.kt");
@@ -5217,46 +5212,6 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/funInterface/basicFunInterface.kt");
         }
 
-        @TestMetadata("basicFunInterfaceConversion.kt")
-        public void testBasicFunInterfaceConversion() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/basicFunInterfaceConversion.kt");
-        }
-
-        @TestMetadata("funConversionInVararg.kt")
-        public void testFunConversionInVararg() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/funConversionInVararg.kt");
-        }
-
-        @TestMetadata("noOptimizedCallableReferences.kt")
-        public void testNoOptimizedCallableReferences() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/noOptimizedCallableReferences.kt");
-        }
-
-        @TestMetadata("partialSam.kt")
-        public void testPartialSam() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/partialSam.kt");
-        }
-
-        @TestMetadata("primitiveConversions.kt")
-        public void testPrimitiveConversions() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/primitiveConversions.kt");
-        }
-
-        @TestMetadata("receiverEvaluatedOnce.kt")
-        public void testReceiverEvaluatedOnce() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/receiverEvaluatedOnce.kt");
-        }
-
-        @TestMetadata("samConstructorExplicitInvocation.kt")
-        public void testSamConstructorExplicitInvocation() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/samConstructorExplicitInvocation.kt");
-        }
-
-        @TestMetadata("samConversionToGenericInterfaceInGenericFun.kt")
-        public void testSamConversionToGenericInterfaceInGenericFun() throws Exception {
-            runTest("compiler/testData/codegen/box/funInterface/samConversionToGenericInterfaceInGenericFun.kt");
-        }
-
         @TestMetadata("compiler/testData/codegen/box/funInterface/equality")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)
@@ -7562,41 +7517,6 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
                 public void testAllFilesPresentInFunInterface() throws Exception {
                     KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface"), Pattern.compile("^([^_](.+))\\.kt$"), null, TargetBackend.WASM, true);
                 }
-
-                @TestMetadata("any.kt")
-                public void testAny() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/any.kt");
-                }
-
-                @TestMetadata("anyN.kt")
-                public void testAnyN() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/anyN.kt");
-                }
-
-                @TestMetadata("iface.kt")
-                public void testIface() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/iface.kt");
-                }
-
-                @TestMetadata("ifaceChild.kt")
-                public void testIfaceChild() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/ifaceChild.kt");
-                }
-
-                @TestMetadata("primitive.kt")
-                public void testPrimitive() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/primitive.kt");
-                }
-
-                @TestMetadata("result.kt")
-                public void testResult() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/result.kt");
-                }
-
-                @TestMetadata("string.kt")
-                public void testString() throws Exception {
-                    runTest("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/string.kt");
-                }
             }
 
             @TestMetadata("compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/lambda")
@@ -12815,11 +12735,6 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/regressions/kt39088.kt");
         }
 
-        @TestMetadata("kt4142.kt")
-        public void testKt4142() throws Exception {
-            runTest("compiler/testData/codegen/box/regressions/kt4142.kt");
-        }
-
         @TestMetadata("kt4281.kt")
         public void testKt4281() throws Exception {
             runTest("compiler/testData/codegen/box/regressions/kt4281.kt");

libraries/stdlib/wasm/internal/kotlin/wasm/internal/TypeInfo.kt

@@ -9,9 +9,11 @@ package kotlin.wasm.internal
 
 internal const val TYPE_INFO_ELEMENT_SIZE = 4
 
-internal const val TYPE_INFO_VTABLE_OFFSET = 2 * TYPE_INFO_ELEMENT_SIZE
+
-internal const val TYPE_INFO_VTABLE_LENGTH_OFFSET = TYPE_INFO_ELEMENT_SIZE
 internal const val SUPER_CLASS_ID_OFFSET = 0
+internal const val TYPE_INFO_ITABLE_PTR_OFFSET = SUPER_CLASS_ID_OFFSET + TYPE_INFO_ELEMENT_SIZE
+internal const val TYPE_INFO_VTABLE_LENGTH_OFFSET = TYPE_INFO_ITABLE_PTR_OFFSET + TYPE_INFO_ELEMENT_SIZE
+internal const val TYPE_INFO_VTABLE_OFFSET = TYPE_INFO_VTABLE_LENGTH_OFFSET + TYPE_INFO_ELEMENT_SIZE
 
 internal fun getVtablePtr(obj: Any): Int =
     obj.typeInfo + TYPE_INFO_VTABLE_OFFSET
@@ -19,8 +21,11 @@ internal fun getVtablePtr(obj: Any): Int =
 internal fun getVtableLength(obj: Any): Int =
     wasm_i32_load(obj.typeInfo + TYPE_INFO_VTABLE_LENGTH_OFFSET)
 
-internal fun getInterfaceListLength(obj: Any): Int =
+internal fun getItablePtr(obj: Any): Int =
-    wasm_i32_load(obj.typeInfo + TYPE_INFO_VTABLE_LENGTH_OFFSET)
+    wasm_i32_load(obj.typeInfo + TYPE_INFO_ITABLE_PTR_OFFSET)
+
+internal fun getInterfaceListLength(itablePtr: Int): Int =
+    wasm_i32_load(itablePtr + TYPE_INFO_VTABLE_LENGTH_OFFSET)
 
 internal fun getSuperClassId(obj: Any): Int =
     wasm_i32_load(obj.typeInfo + SUPER_CLASS_ID_OFFSET)
@@ -31,17 +36,22 @@ internal fun getVirtualMethodId(obj: Any, virtualFunctionSlot: Int): Int {
     return wasm_i32_load(methodIdPtr)
 }
 
-internal fun getInterfaceMethodId(obj: Any, methodSignatureId: Int): Int {
+// Returns -1 if obj does not implement interface
-    val vtableLength = getVtableLength(obj)
+internal fun getInterfaceImplId(obj: Any, interfaceId: Int): Int {
-    val vtableSignatures = getVtablePtr(obj) + vtableLength * TYPE_INFO_ELEMENT_SIZE
+    val interfaceListSizePtr = getItablePtr(obj)
-    var virtualFunctionSlot = 0
+    val interfaceListPtr = interfaceListSizePtr + TYPE_INFO_ELEMENT_SIZE
-    while (virtualFunctionSlot < vtableLength) {
+    val interfaceListSize = wasm_i32_load(interfaceListSizePtr)
-        if (wasm_i32_load(vtableSignatures + virtualFunctionSlot * TYPE_INFO_ELEMENT_SIZE) == methodSignatureId) {
+
-            return getVirtualMethodId(obj, virtualFunctionSlot)
+    var interfaceSlot = 0
+    while (interfaceSlot < interfaceListSize) {
+        val supportedInterface = wasm_i32_load(interfaceListPtr + interfaceSlot * TYPE_INFO_ELEMENT_SIZE)
+        if (supportedInterface == interfaceId) {
+            return wasm_i32_load(interfaceListPtr + interfaceListSize * TYPE_INFO_ELEMENT_SIZE + interfaceSlot * TYPE_INFO_ELEMENT_SIZE)
         }
-        virtualFunctionSlot++
+        interfaceSlot++
     }
-    wasm_unreachable()
+
+    return -1
 }
 
 
@@ -57,21 +67,7 @@ internal fun isSubClass(obj: Any, classId: Int): Boolean {
 }
 
 internal fun isInterface(obj: Any, interfaceId: Int): Boolean {
-    val vtableLength = getVtableLength(obj)
+    return getInterfaceImplId(obj, interfaceId) != -1
-    val interfaceListSizePtr = getVtablePtr(obj) + 2 * vtableLength * TYPE_INFO_ELEMENT_SIZE
-    val interfaceListPtr = interfaceListSizePtr + TYPE_INFO_ELEMENT_SIZE
-    val interfaceListSize = wasm_i32_load(interfaceListSizePtr)
-
-    var interfaceSlot = 0
-    while (interfaceSlot < interfaceListSize) {
-        val supportedInterface = wasm_i32_load(interfaceListPtr + interfaceSlot * TYPE_INFO_ELEMENT_SIZE)
-        if (supportedInterface == interfaceId) {
-            return true
-        }
-        interfaceSlot++
-    }
-
-    return false
 }
 
 @ExcludedFromCodegen

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Declarations.kt

@@ -76,7 +76,7 @@ class WasmData(
 ) : WasmNamedModuleField()
 
 class WasmTable(
-    val limits: WasmLimits = WasmLimits(1u, null),
+    var limits: WasmLimits = WasmLimits(1u, null),
     val elementType: WasmType,
     val importPair: WasmImportPair? = null
 ) : WasmNamedModuleField() {

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt

@@ -73,7 +73,9 @@ sealed class WasmImmediate {
     }
 
     class DataIdx(val value: Int) : WasmImmediate()
-    class TableIdx(val value: Int) : WasmImmediate()
+    class TableIdx(val value: WasmSymbolReadOnly<Int>) : WasmImmediate() {
+        constructor(value: Int) : this(WasmSymbol(value))
+    }
 
     class LabelIdx(val value: Int) : WasmImmediate()
     class LabelIdxVector(val value: List<Int>) : WasmImmediate()

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Symbol.kt

@@ -33,3 +33,10 @@ class WasmSymbol<out T : Any>(owner: T? = null) : WasmSymbolReadOnly<T> {
     override fun toString(): String =
         _owner?.toString() ?: "UNBOUND-WASM-SYMBOL"
 }
+
+class WasmSymbolIntWrapper(val symbol: WasmSymbol<WasmNamedModuleField>) : WasmSymbolReadOnly<Int> {
+    override val owner: Int
+        get() = symbol.owner.id!!
+
+    override fun toString() = owner.toString()
+}

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/WasmExpressionBuilder.kt

@@ -82,11 +82,14 @@ abstract class WasmExpressionBuilder {
         buildInstr(WasmOp.CALL, WasmImmediate.FuncIdx(symbol))
     }
 
-    fun buildCallIndirect(symbol: WasmSymbol<WasmFunctionType>) {
+    fun buildCallIndirect(
+        symbol: WasmSymbol<WasmFunctionType>,
+        tableIdx: WasmSymbolReadOnly<Int> = WasmSymbol(0),
+    ) {
         buildInstr(
             WasmOp.CALL_INDIRECT,
             WasmImmediate.TypeIdx(symbol),
-            WasmImmediate.TableIdx(0)
+            WasmImmediate.TableIdx(tableIdx)
         )
     }
 

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/WasmIrExpressionBuilder.kt

@@ -23,3 +23,9 @@ class WasmIrExpressionBuilder(
     override val lastInstr: WasmOp?
         get() = expression.lastOrNull()?.operator
 }
+
+inline fun buildWasmExpression(body: WasmExpressionBuilder.() -> Unit): MutableList<WasmInstr> {
+    val res = mutableListOf<WasmInstr>()
+    WasmIrExpressionBuilder(res).body()
+    return res
+}

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/convertors/WasmIrToBinary.kt

@@ -138,7 +138,7 @@ class WasmIrToBinary(outputStream: OutputStream, val module: WasmModule) {
             is WasmImmediate.TypeIdx -> appendModuleFieldReference(x.value.owner)
             is WasmImmediate.MemoryIdx -> appendModuleFieldReference(x.value.owner)
             is WasmImmediate.DataIdx -> b.writeVarUInt32(x.value)
-            is WasmImmediate.TableIdx -> b.writeVarUInt32(x.value)
+            is WasmImmediate.TableIdx -> b.writeVarUInt32(x.value.owner)
             is WasmImmediate.LabelIdx -> b.writeVarUInt32(x.value)
             is WasmImmediate.LabelIdxVector -> {
                 b.writeVarUInt32(x.value.size)
@@ -243,7 +243,7 @@ class WasmIrToBinary(outputStream: OutputStream, val module: WasmModule) {
             b.writeByte(1)
         }
 
-        b.writeVarInt7(table.elementType.code)
+        appendType(table.elementType)
         appendLimits(table.limits)
     }
 
@@ -286,7 +286,7 @@ class WasmIrToBinary(outputStream: OutputStream, val module: WasmModule) {
     }
 
     private fun appendElement(element: WasmElement) {
-        val isFuncIndices = element.values.all { it is WasmTable.Value.Function }
+        val isFuncIndices = element.values.all { it is WasmTable.Value.Function } && element.type == WasmFuncRef
 
         val funcIndices = if (isFuncIndices) {
             element.values.map { (it as WasmTable.Value.Function).function.owner.id!! }