[WASM] New VTable format

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

@@ -173,9 +173,6 @@ class WasmSymbols(
     val wasmClassId = getInternalFunction("wasmClassId")
     val wasmInterfaceId = getInternalFunction("wasmInterfaceId")
 
-    val getVirtualMethodId = getInternalFunction("getVirtualMethodId")
-    val getInterfaceImplId = getInternalFunction("getInterfaceImplId")
-
     val isInterface = getInternalFunction("isInterface")
 
     val nullableEquals = getInternalFunction("nullableEquals")

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

@@ -80,6 +80,7 @@ fun compileWasm(
 ): WasmCompilerResult {
     val compiledWasmModule = WasmCompiledModuleFragment(backendContext.irBuiltIns)
     val codeGenerator = WasmModuleFragmentGenerator(backendContext, compiledWasmModule, allowIncompleteImplementations = allowIncompleteImplementations)
+    allModules.forEach { codeGenerator.collectInterfaceTables(it) }
     allModules.forEach { codeGenerator.generateModule(it) }
 
     val linkedModule = compiledWasmModule.linkWasmCompiledFragments()

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/dce/WasmUsefulDeclarationProcessor.kt

@@ -97,11 +97,8 @@ internal class WasmUsefulDeclarationProcessor(
             val isSuperCall = expression.superQualifierSymbol != null
             if (function is IrSimpleFunction && function.isOverridable && !isSuperCall) {
                 val klass = function.parentAsClass
-                if (!klass.isInterface) {
-                    context.wasmSymbols.getVirtualMethodId.owner.enqueue(data, "call on class receiver")
-                } else {
+                if (klass.isInterface) {
                     klass.enqueue(data, "receiver class")
-                    context.wasmSymbols.getInterfaceImplId.owner.enqueue(data, "call on interface receiver")
                 }
                 function.enqueue(data, "method call")
             }
@@ -134,7 +131,7 @@ internal class WasmUsefulDeclarationProcessor(
     }
 
     private fun IrType.enqueueRuntimeClassOrAny(from: IrDeclaration, info: String): Unit =
-        (this.getRuntimeClass ?: context.wasmSymbols.any.owner).enqueue(from, info, isContagious = false)
+        this.getRuntimeClass(context.irBuiltIns).enqueue(from, info, isContagious = false)
 
     private fun IrType.enqueueType(from: IrDeclaration, info: String) {
         getInlinedValueTypeIfAny()

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

@@ -10,9 +10,7 @@ package org.jetbrains.kotlin.backend.wasm.ir2wasm
 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.utils.getWasmArrayAnnotation
-import org.jetbrains.kotlin.backend.wasm.utils.getWasmOpAnnotation
-import org.jetbrains.kotlin.backend.wasm.utils.hasWasmNoOpCastAnnotation
+import org.jetbrains.kotlin.backend.wasm.utils.*
 import org.jetbrains.kotlin.backend.wasm.utils.isCanonical
 import org.jetbrains.kotlin.ir.IrBuiltIns
 import org.jetbrains.kotlin.ir.IrElement
@@ -29,7 +27,10 @@ import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.js.config.JSConfigurationKeys
 import org.jetbrains.kotlin.wasm.ir.*
 
-class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorVoid {
+class BodyGenerator(
+    val context: WasmFunctionCodegenContext,
+    private val hierarchyDisjointUnions: DisjointUnions<IrClassSymbol>
+) : IrElementVisitorVoid {
     val body: WasmExpressionBuilder = context.bodyGen
 
     // Shortcuts
@@ -117,7 +118,7 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
                 generateInstanceFieldAccess(field)
             }
         } else {
-            body.buildGetGlobal(context.referenceGlobal(field.symbol))
+            body.buildGetGlobal(context.referenceGlobalField(field.symbol))
         }
     }
 
@@ -154,7 +155,7 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
             )
         } else {
             generateExpression(expression.value)
-            body.buildSetGlobal(context.referenceGlobal(expression.symbol))
+            body.buildSetGlobal(context.referenceGlobalField(expression.symbol))
         }
 
         body.buildGetUnit()
@@ -203,6 +204,14 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
             return
         }
 
+        //ClassITable and VTable load
+        body.buildGetGlobal(context.referenceGlobalVTable(klass.symbol))
+        if (klass.hasInterfaceForClass()) {
+            body.buildGetGlobal(context.referenceGlobalClassITable(klass.symbol))
+        } else {
+            body.buildRefNull(WasmHeapType.Simple.Data)
+        }
+
         val wasmClassId = context.referenceClassId(klass.symbol)
 
         val irFields: List<IrField> = klass.allFields(backendContext.irBuiltIns)
@@ -214,7 +223,6 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
                 generateDefaultInitializerForType(context.transformType(field.type), body)
         }
 
-        generateClassRTT(klass.symbol)
         body.buildStructNew(wasmGcType)
         generateCall(expression)
     }
@@ -236,16 +244,21 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
         // Box intrinsic has an additional klass ID argument.
         // Processing it separately
         if (call.symbol == wasmSymbols.boxIntrinsic) {
-            val toType = call.getTypeArgument(0)!!
-            val klass = toType.getRuntimeClass!!
-            val structTypeName = context.referenceGcType(klass.symbol)
-            val klassId = context.referenceClassId(klass.symbol)
+            val klass = call.getTypeArgument(0)!!.getRuntimeClass(irBuiltIns)
+            val klassSymbol = klass.symbol
 
-            body.buildConstI32Symbol(klassId)
+            //ClassITable and VTable load
+            body.buildGetGlobal(context.referenceGlobalVTable(klassSymbol))
+            if (klass.hasInterfaceForClass()) {
+                body.buildGetGlobal(context.referenceGlobalClassITable(klassSymbol))
+            } else {
+                body.buildRefNull(WasmHeapType.Simple.Data)
+            }
+
+            body.buildConstI32Symbol(context.referenceClassId(klassSymbol))
             body.buildConstI32(0) // Any::_hashCode
             generateExpression(call.getValueArgument(0)!!)
-            generateClassRTT(klass.symbol)
-            body.buildStructNew(structTypeName)
+            body.buildStructNew(context.referenceGcType(klassSymbol))
             return
         }
 
@@ -296,20 +309,35 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
                 val vfSlot = classMetadata.virtualMethods.indexOfFirst { it.function == function }
                 // Dispatch receiver should be simple and without side effects at this point
                 // TODO: Verify
-                generateExpression(call.dispatchReceiver!!)
-                body.buildConstI32(vfSlot)
-                body.buildCall(context.referenceFunction(wasmSymbols.getVirtualMethodId))
-                body.buildCallIndirect(
-                    symbol = context.referenceFunctionType(function.symbol)
-                )
+                val receiver = call.dispatchReceiver!!
+                generateExpression(receiver)
+
+                if (!receiver.type.getRuntimeClass(irBuiltIns).isSubclassOf(klass)) {
+                    body.buildRefCastStatic(toType = context.referenceGcType(klass.symbol))
+                }
+
+                body.buildStructGet(context.referenceGcType(klass.symbol), WasmSymbol(0))
+                body.buildStructGet(context.referenceVTableGcType(klass.symbol), WasmSymbol(vfSlot))
+                body.buildInstr(WasmOp.CALL_REF)
             } else {
-                generateExpression(call.dispatchReceiver!!)
-                body.buildConstI32Symbol(context.referenceInterfaceId(klass.symbol))
-                body.buildCall(context.referenceFunction(wasmSymbols.getInterfaceImplId))
-                body.buildCallIndirect(
-                    tableIdx = WasmSymbolIntWrapper(context.referenceInterfaceTable(function.symbol)),
-                    symbol = context.referenceFunctionType(function.symbol)
-                )
+                val symbol = klass.symbol
+                if (symbol in hierarchyDisjointUnions) {
+                    generateExpression(call.dispatchReceiver!!)
+
+                    body.buildStructGet(context.referenceGcType(irBuiltIns.anyClass), WasmSymbol(1))
+
+                    val classITableReference = context.referenceClassITableGcType(symbol)
+                    body.buildRefCastStatic(classITableReference)
+                    body.buildStructGet(classITableReference, context.referenceClassITableInterfaceSlot(symbol))
+
+                    val vfSlot = context.getInterfaceMetadata(symbol).methods
+                        .indexOfFirst { it.function == function }
+
+                    body.buildStructGet(context.referenceVTableGcType(symbol), WasmSymbol(vfSlot))
+                    body.buildInstr(WasmOp.CALL_REF)
+                } else {
+                    body.buildUnreachable()
+                }
             }
 
         } else {
@@ -322,13 +350,14 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
             body.buildGetUnit()
     }
 
-    private fun generateTypeRTT(type: IrType) {
-        val klass = type.getRuntimeClass?.symbol ?: context.backendContext.irBuiltIns.anyClass
-        generateClassRTT(klass)
+    private fun generateRefCast(type: IrType) {
+        body.buildRefCastStatic(
+            context.referenceGcType(type.getRuntimeClass(irBuiltIns).symbol)
+        )
     }
 
-    private fun generateClassRTT(klass: IrClassSymbol) {
-        body.buildRttCanon(context.referenceGcType(klass))
+    private fun generateTypeRTT(type: IrType) {
+        body.buildRttCanon(context.referenceGcType(type.getRuntimeClass(irBuiltIns).symbol))
     }
 
     // Return true if generated.
@@ -356,10 +385,35 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
                 body.buildConstI32Symbol(context.referenceInterfaceId(irInterface.symbol))
             }
 
+            wasmSymbols.isInterface -> {
+                val irInterface = call.getTypeArgument(0)!!.getClass()
+                    ?: error("No interface given for wasmInterfaceId intrinsic")
+                assert(irInterface.isInterface)
+                if (irInterface.symbol in hierarchyDisjointUnions) {
+                    val classITable = context.referenceClassITableGcType(irInterface.symbol)
+                    val parameterLocal = context.referenceLocal(SyntheticLocalType.IS_INTERFACE_PARAMETER)
+                    body.buildSetLocal(parameterLocal)
+                    body.buildBlock("isInterface", WasmI32) { outerLabel ->
+                        body.buildBlock("isInterface", WasmRefNullType(WasmHeapType.Simple.Data)) { innerLabel ->
+                            body.buildGetLocal(parameterLocal)
+                            body.buildStructGet(context.referenceGcType(irBuiltIns.anyClass), WasmSymbol(1))
+                            body.buildBrInstr(WasmOp.BR_ON_CAST_STATIC_FAIL, innerLabel, classITable)
+                            body.buildStructGet(classITable, context.referenceClassITableInterfaceSlot(irInterface.symbol))
+                            body.buildInstr(WasmOp.REF_IS_NULL)
+                            body.buildInstr(WasmOp.I32_EQZ)
+                            body.buildBr(outerLabel)
+                        }
+                        body.buildDrop()
+                        body.buildConstI32(0)
+                    }
+                } else {
+                    body.buildDrop()
+                    body.buildConstI32(0)
+                }
+            }
+
             wasmSymbols.wasmRefCast -> {
-                val toType = call.getTypeArgument(0)!!
-                generateTypeRTT(toType)
-                body.buildRefCast()
+                generateRefCast(call.getTypeArgument(0)!!)
             }
 
             wasmSymbols.refTest -> {
@@ -443,7 +497,8 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
 
     override fun visitReturn(expression: IrReturn) {
         if (expression.returnTargetSymbol.owner.returnType(backendContext) == irBuiltIns.unitType &&
-            expression.returnTargetSymbol.owner != unitGetInstance) {
+            expression.returnTargetSymbol.owner != unitGetInstance
+        ) {
             generateStatement(expression.value)
         } else {
             generateExpression(expression.value)
@@ -499,24 +554,17 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
 
         val label = loop.label
 
-        body.buildLoop(label)
-        val wasmLoop = body.numberOfNestedBlocks
-
-        body.buildBlock("BREAK_$label")
-        val wasmBreakBlock = body.numberOfNestedBlocks
-
-        body.buildBlock("CONTINUE_$label")
-        val wasmContinueBlock = body.numberOfNestedBlocks
-
-        context.defineLoopLevel(loop, LoopLabelType.BREAK, wasmBreakBlock)
-        context.defineLoopLevel(loop, LoopLabelType.CONTINUE, wasmContinueBlock)
-
-        loop.body?.let { generateStatement(it) }
-        body.buildEnd()
-        generateExpression(loop.condition)
-        body.buildBrIf(wasmLoop)
-        body.buildEnd()
-        body.buildEnd()
+        body.buildLoop(label) { wasmLoop ->
+            body.buildBlock("BREAK_$label") { wasmBreakBlock ->
+                body.buildBlock("CONTINUE_$label") { wasmContinueBlock ->
+                    context.defineLoopLevel(loop, LoopLabelType.BREAK, wasmBreakBlock)
+                    context.defineLoopLevel(loop, LoopLabelType.CONTINUE, wasmContinueBlock)
+                    loop.body?.let { generateStatement(it) }
+                }
+                generateExpression(loop.condition)
+                body.buildBrIf(wasmLoop)
+            }
+        }
 
         body.buildGetUnit()
     }
@@ -530,24 +578,20 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
 
         val label = loop.label
 
-        body.buildLoop(label)
-        val wasmLoop = body.numberOfNestedBlocks
+        body.buildLoop(label) { wasmLoop ->
+            body.buildBlock("BREAK_$label") { wasmBreakBlock ->
+                context.defineLoopLevel(loop, LoopLabelType.BREAK, wasmBreakBlock)
+                context.defineLoopLevel(loop, LoopLabelType.CONTINUE, wasmLoop)
 
-        body.buildBlock("BREAK_$label")
-        val wasmBreakBlock = body.numberOfNestedBlocks
-
-        context.defineLoopLevel(loop, LoopLabelType.BREAK, wasmBreakBlock)
-        context.defineLoopLevel(loop, LoopLabelType.CONTINUE, wasmLoop)
-
-        generateExpression(loop.condition)
-        body.buildInstr(WasmOp.I32_EQZ)
-        body.buildBrIf(wasmBreakBlock)
-        loop.body?.let {
-            generateStatement(it)
+                generateExpression(loop.condition)
+                body.buildInstr(WasmOp.I32_EQZ)
+                body.buildBrIf(wasmBreakBlock)
+                loop.body?.let {
+                    generateStatement(it)
+                }
+                body.buildBr(wasmLoop)
+            }
         }
-        body.buildBr(wasmLoop)
-        body.buildEnd()
-        body.buildEnd()
 
         body.buildGetUnit()
     }
@@ -564,7 +608,7 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
     }
 
     // Return true if function is recognized as intrinsic.
-    fun tryToGenerateWasmOpIntrinsicCall(call: IrFunctionAccessExpression, function: IrFunction): Boolean {
+    private fun tryToGenerateWasmOpIntrinsicCall(call: IrFunctionAccessExpression, function: IrFunction): Boolean {
         if (function.hasWasmNoOpCastAnnotation()) {
             return true
         }

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

@@ -22,14 +22,18 @@ import org.jetbrains.kotlin.ir.expressions.IrBlockBody
 import org.jetbrains.kotlin.ir.expressions.IrConst
 import org.jetbrains.kotlin.ir.expressions.IrConstKind
 import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
+import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.name.parentOrNull
 import org.jetbrains.kotlin.wasm.ir.*
 
-class DeclarationGenerator(val context: WasmModuleCodegenContext, private val allowIncompleteImplementations: Boolean) : IrElementVisitorVoid {
+class DeclarationGenerator(
+    val context: WasmModuleCodegenContext,
+    private val allowIncompleteImplementations: Boolean,
+    private val hierarchyDisjointUnions: DisjointUnions<IrClassSymbol>,
+) : IrElementVisitorVoid {
 
     // Shortcuts
     private val backendContext: WasmBackendContext = context.backendContext
@@ -90,13 +94,8 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
             )
         context.defineFunctionType(declaration.symbol, wasmFunctionType)
 
-        if (declaration is IrSimpleFunction) {
-            if (declaration.modality == Modality.ABSTRACT) return
-            if (declaration.isOverridableOrOverrides) {
-                // Register function as virtual, meaning this function
-                // will be stored Wasm table and could be called indirectly.
-                context.registerVirtualFunction(declaration.symbol)
-            }
+        if (declaration is IrSimpleFunction && declaration.modality == Modality.ABSTRACT) {
+            return
         }
 
         assert(declaration == declaration.realOverrideTarget) {
@@ -128,7 +127,7 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
         }
 
         val exprGen = functionCodegenContext.bodyGen
-        val bodyBuilder = BodyGenerator(functionCodegenContext)
+        val bodyBuilder = BodyGenerator(functionCodegenContext, hierarchyDisjointUnions)
 
         require(declaration.body is IrBlockBody) { "Only IrBlockBody is supported" }
         declaration.body?.acceptVoid(bodyBuilder)
@@ -167,12 +166,143 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
         }
     }
 
+    private fun createDeclarationByInterface(iFace: IrClassSymbol) {
+        if (context.isAlreadyDefinedClassITableGcType(iFace)) return
+        if (iFace !in hierarchyDisjointUnions) return
+
+        val iFacesUnion = hierarchyDisjointUnions[iFace]
+
+        val fields = iFacesUnion.mapIndexed { index, unionIFace ->
+            context.defineClassITableInterfaceSlot(unionIFace, index)
+            WasmStructFieldDeclaration(
+                name = "${unionIFace.owner.fqNameWhenAvailable.toString()}.itable",
+                type = WasmRefNullType(WasmHeapType.Type(context.referenceVTableGcType(unionIFace))),
+                isMutable = false
+            )
+        }
+
+        val struct = WasmStructDeclaration(
+            name = "classITable",
+            fields = fields,
+            superType = null
+        )
+
+        iFacesUnion.forEach {
+            context.defineClassITableGcType(it, struct)
+        }
+    }
+
+    private fun createVirtualTableStruct(
+        methods: List<VirtualMethodMetadata>,
+        name: String,
+        superType: WasmSymbolReadOnly<WasmTypeDeclaration>? = null,
+    ): WasmStructDeclaration {
+        val tableFields = methods.map {
+            WasmStructFieldDeclaration(
+                name = it.signature.name.asString(),
+                type = WasmRefNullType(WasmHeapType.Type(context.referenceFunctionType(it.function.symbol))),
+                isMutable = false
+            )
+        }
+
+        return WasmStructDeclaration(
+            name = name,
+            fields = tableFields,
+            superType = superType,
+        )
+    }
+
+    private fun createVTable(metadata: ClassMetadata) {
+        val klass = metadata.klass
+        val symbol = klass.symbol
+        val vtableName = "${klass.fqNameWhenAvailable}.vtable"
+        val vtableStruct = createVirtualTableStruct(
+            metadata.virtualMethods,
+            vtableName,
+            superType = metadata.superClass?.klass?.symbol?.let(context::referenceVTableGcType)
+        )
+        context.defineVTableGcType(metadata.klass.symbol, vtableStruct)
+
+        if (klass.isAbstractOrSealed) return
+
+        val vTableTypeReference = context.referenceVTableGcType(symbol)
+        val vTableRefGcType = WasmRefType(WasmHeapType.Type(vTableTypeReference))
+
+        val initVTableGlobal = buildWasmExpression {
+            metadata.virtualMethods.forEachIndexed { i, method ->
+                if (method.function.modality != Modality.ABSTRACT) {
+                    buildInstr(WasmOp.REF_FUNC, WasmImmediate.FuncIdx(context.referenceFunction(method.function.symbol)))
+                } else {
+                    check(allowIncompleteImplementations) {
+                        "Cannot find class implementation of method ${method.signature} in class ${klass.fqNameWhenAvailable}"
+                    }
+                    //This erased by DCE so abstract version appeared in non-abstract class
+                    buildRefNull(vtableStruct.fields[i].type.getHeapType())
+                }
+            }
+            buildStructNew(vTableTypeReference)
+        }
+        context.defineGlobalVTable(
+            irClass = symbol,
+            wasmGlobal = WasmGlobal(vtableName, vTableRefGcType, false, initVTableGlobal)
+        )
+    }
+
+    private fun createClassITable(metadata: ClassMetadata) {
+        val klass = metadata.klass
+        if (klass.isAbstractOrSealed) return
+        val supportedInterface = metadata.interfaces.firstOrNull()?.symbol ?: return
+
+        createDeclarationByInterface(supportedInterface)
+
+        val classInterfaceType = context.referenceClassITableGcType(supportedInterface)
+        val interfaceList = hierarchyDisjointUnions[supportedInterface]
+
+        val initITableGlobal = buildWasmExpression {
+            for (iFace in interfaceList) {
+                val iFaceVTableGcType = context.referenceVTableGcType(iFace)
+                val iFaceVTableGcNullHeapType = WasmHeapType.Type(iFaceVTableGcType)
+
+                if (!metadata.interfaces.contains(iFace.owner)) {
+                    buildRefNull(iFaceVTableGcNullHeapType)
+                    continue
+                }
+
+                for (method in context.getInterfaceMetadata(iFace).methods) {
+                    val classMethod: VirtualMethodMetadata? = metadata.virtualMethods
+                        .find { it.signature == method.signature && it.function.modality != Modality.ABSTRACT }  // TODO: Use map
+
+                    if (classMethod == null && !allowIncompleteImplementations) {
+                        error("Cannot find interface implementation of method ${method.signature} in class ${klass.fqNameWhenAvailable}")
+                    }
+
+                    if (classMethod != null) {
+                        val functionTypeReference = context.referenceFunction(classMethod.function.symbol)
+                        buildInstr(WasmOp.REF_FUNC, WasmImmediate.FuncIdx(functionTypeReference))
+                    } else {
+                        //This erased by DCE so abstract version appeared in non-abstract class
+                        buildRefNull(WasmHeapType.Type(context.referenceFunctionType(method.function.symbol)))
+                    }
+                }
+                buildStructNew(iFaceVTableGcType)
+            }
+            buildStructNew(classInterfaceType)
+        }
+
+        val wasmClassIFaceGlobal = WasmGlobal(
+            name = "${klass.fqNameWhenAvailable.toString()}.classITable",
+            type = WasmRefType(WasmHeapType.Type(classInterfaceType)),
+            isMutable = false,
+            init = initITableGlobal
+        )
+        context.defineGlobalClassITable(klass.symbol, wasmClassIFaceGlobal)
+    }
+
     override fun visitClass(declaration: IrClass) {
         if (declaration.isAnnotationClass) return
         if (declaration.isExternal) return
         val symbol = declaration.symbol
 
-
         // Handle arrays
         declaration.getWasmArrayAnnotation()?.let { wasmArrayAnnotation ->
             val nameStr = declaration.fqNameWhenAvailable.toString()
@@ -189,60 +319,43 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
             return
         }
 
+        val nameStr = declaration.fqNameWhenAvailable.toString()
+
         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)))
+            if (symbol in hierarchyDisjointUnions) {
+                val vtableStruct = createVirtualTableStruct(
+                    methods = context.getInterfaceMetadata(symbol).methods,
+                    name = "$nameStr.itable"
                 )
-                context.defineInterfaceMethodTable(methodSymbol, table)
+                context.defineVTableGcType(symbol, vtableStruct)
             }
-            context.registerInterface(symbol)
         } else {
-            val nameStr = declaration.fqNameWhenAvailable.toString()
             val metadata = context.getClassMetadata(symbol)
+
+            createVTable(metadata)
+            createClassITable(metadata)
+
+            val vtableRefGcType = WasmRefType(WasmHeapType.Type(context.referenceVTableGcType(symbol)))
+            val classITableRefGcType = WasmRefNullType(WasmHeapType.Simple.Data)
+            val fields = mutableListOf<WasmStructFieldDeclaration>()
+            fields.add(WasmStructFieldDeclaration("vtable", vtableRefGcType, false))
+            fields.add(WasmStructFieldDeclaration("itable", classITableRefGcType, false))
+            declaration.allFields(irBuiltIns).mapTo(fields) {
+                WasmStructFieldDeclaration(
+                    name = it.name.toString(),
+                    type = context.transformFieldType(it.type),
+                    isMutable = true
+                )
+            }
+
             val superClass = metadata.superClass
             val structType = WasmStructDeclaration(
                 name = nameStr,
-                fields = declaration.allFields(irBuiltIns).map {
-                    WasmStructFieldDeclaration(
-                        name = it.name.toString(),
-                        type = context.transformFieldType(it.type),
-                        isMutable = true
-                    )
-                },
-                superClass?.let { context.referenceGcType(superClass.klass.symbol) }
+                fields = fields,
+                superType = superClass?.let { context.referenceGcType(superClass.klass.symbol) }
             )
-
             context.defineGcType(symbol, structType)
-            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 && it.function.modality != Modality.ABSTRACT }  // TODO: Use map
-
-                        if (classMethod == null && !allowIncompleteImplementations) {
-                            error("Cannot find class implementation of method ${method.signature} in class ${declaration.fqNameWhenAvailable}")
-                        }
-                        val matchedMethod = classMethod?.let { context.referenceFunction(it.function.symbol) }
-                        method.function.symbol as IrFunctionSymbol to matchedMethod
-                    }
-
-                    context.registerInterfaceImplementationMethod(
-                        interfaceImplementation,
-                        table
-                    )
-                }
-            }
         }
 
         for (member in declaration.declarations) {
@@ -251,15 +364,13 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
     }
 
     private fun binaryDataStruct(classMetadata: ClassMetadata): ConstantDataStruct {
-        val invalidIndex = -1
-
         val fqnShouldBeEmitted = context.backendContext.configuration.languageVersionSettings.getFlag(allowFullyQualifiedNameInKClass)
         //TODO("FqName for inner classes could be invalid due to topping it out from outer class")
         val packageName = if (fqnShouldBeEmitted) classMetadata.klass.kotlinFqName.parentOrNull()?.asString() ?: "" else ""
         val simpleName = classMetadata.klass.kotlinFqName.shortName().asString()
         val typeInfo = ConstantDataStruct(
-            "TypeInfo",
-            listOf(
+            name = "TypeInfo",
+            elements = listOf(
                 ConstantDataIntField("TypePackageNameLength", packageName.length),
                 ConstantDataIntField("TypePackageNamePtr", context.referenceStringLiteral(packageName)),
                 ConstantDataIntField("TypeNameLength", simpleName.length),
@@ -272,40 +383,17 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
             ConstantDataIntField("SuperTypeId", context.referenceClassId(it.symbol))
         } ?: ConstantDataIntField("SuperTypeId", -1)
 
-        val vtableSizeField = ConstantDataIntField(
-            "V-table length",
-            classMetadata.virtualMethods.size
-        )
-
-        val vtableArray = ConstantDataIntArray(
-            "V-table",
-            classMetadata.virtualMethods.map {
-                if (it.function.modality == Modality.ABSTRACT) {
-                    WasmSymbol(invalidIndex)
-                } else {
-                    context.referenceVirtualFunctionId(it.function.symbol)
-                }
-            }
-        )
-
-        val interfaceTablePtr = ConstantDataIntField(
-            "interfaceTablePtr",
-            context.referenceInterfaceTableAddress(classMetadata.klass.symbol)
-        )
+        val typeInfoContent = mutableListOf(typeInfo, superTypeId)
+        if (!classMetadata.klass.isAbstractOrSealed) {
+            typeInfoContent.add(interfaceTable(classMetadata))
+        }
 
         return ConstantDataStruct(
-            "Class TypeInfo: ${classMetadata.klass.fqNameWhenAvailable} ",
-            listOf(
-                typeInfo,
-                superTypeId,
-                interfaceTablePtr,
-                vtableSizeField,
-                vtableArray,
-            )
+            name = "Class TypeInfo: ${classMetadata.klass.fqNameWhenAvailable} ",
+            elements = typeInfoContent
         )
     }
 
-
     private fun interfaceTable(classMetadata: ClassMetadata): ConstantDataStruct {
         val interfaces = classMetadata.interfaces
         val size = ConstantDataIntField("size", interfaces.size)
@@ -313,20 +401,10 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
             "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,
-            )
+            name = "Class interface table: ${classMetadata.klass.fqNameWhenAvailable} ",
+            elements = listOf(size, interfaceIds)
         )
     }
 
@@ -357,7 +435,7 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext, private val al
             init = initBody
         )
 
-        context.defineGlobal(declaration.symbol, global)
+        context.defineGlobalField(declaration.symbol, global)
     }
 }
 

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

@@ -44,8 +44,8 @@ class WasmTypeTransformer(
                 toWasmValueType()
         }
 
-    fun IrType.toWasmGcRefType(): WasmType =
-        WasmRefNullType(WasmHeapType.Type(context.referenceGcType(getRuntimeClass?.symbol ?: builtIns.anyClass)))
+    private fun IrType.toWasmGcRefType(): WasmType =
+        WasmRefNullType(WasmHeapType.Type(context.referenceGcType(getRuntimeClass(context.backendContext.irBuiltIns).symbol)))
 
     fun IrType.toBoxedInlineClassType(): WasmType =
         toWasmGcRefType()
@@ -122,8 +122,5 @@ fun isBuiltInWasmRefType(type: IrType): Boolean {
 fun isExternalType(type: IrType): Boolean =
     type.erasedUpperBound?.isExternal ?: false
 
-val IrType.getRuntimeClass: IrClass?
-    get() = erasedUpperBound.let {
-        if (it?.isInterface == true) null
-        else it
-    }
+fun IrType.getRuntimeClass(irBuiltIns: IrBuiltIns): IrClass =
+    erasedUpperBound?.takeIf { !it.isInterface } ?: irBuiltIns.anyClass.owner

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

@@ -6,13 +6,9 @@
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
-import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
-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.ir.symbols.*
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.wasm.ir.*
 
@@ -22,17 +18,20 @@ interface WasmBaseCodegenContext {
     val scratchMemAddr: WasmSymbol<Int>
 
     fun referenceFunction(irFunction: IrFunctionSymbol): WasmSymbol<WasmFunction>
-    fun referenceGlobal(irField: IrFieldSymbol): WasmSymbol<WasmGlobal>
+    fun referenceGlobalField(irField: IrFieldSymbol): WasmSymbol<WasmGlobal>
+    fun referenceGlobalVTable(irClass: IrClassSymbol): WasmSymbol<WasmGlobal>
+    fun referenceGlobalClassITable(irClass: IrClassSymbol): WasmSymbol<WasmGlobal>
     fun referenceGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration>
+    fun referenceVTableGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration>
+    fun referenceClassITableGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration>
+    fun defineClassITableGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration)
+    fun isAlreadyDefinedClassITableGcType(irClass: IrClassSymbol): Boolean
+    fun referenceClassITableInterfaceSlot(irClass: IrClassSymbol): WasmSymbol<Int>
+    fun defineClassITableInterfaceSlot(irClass: IrClassSymbol, slot: Int)
     fun referenceFunctionType(irFunction: IrFunctionSymbol): WasmSymbol<WasmFunctionType>
 
     fun referenceClassId(irClass: IrClassSymbol): WasmSymbol<Int>
     fun referenceInterfaceId(irInterface: IrClassSymbol): WasmSymbol<Int>
-    fun referenceVirtualFunctionId(irFunction: IrSimpleFunctionSymbol): WasmSymbol<Int>
-
-    fun referenceSignatureId(signature: WasmSignature): WasmSymbol<Int>
-
-    fun referenceInterfaceTable(irFunction: IrFunctionSymbol): WasmSymbol<WasmTable>
 
     fun referenceStringLiteral(string: String): WasmSymbol<Int>
 
@@ -47,4 +46,5 @@ interface WasmBaseCodegenContext {
 
     fun getStructFieldRef(field: IrField): WasmSymbol<Int>
     fun getClassMetadata(irClass: IrClassSymbol): ClassMetadata
+    fun getInterfaceMetadata(irClass: IrClassSymbol): InterfaceMetadata
 }

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

@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
-import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
 import org.jetbrains.kotlin.ir.IrBuiltIns
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithName
 import org.jetbrains.kotlin.ir.declarations.IrExternalPackageFragment
@@ -17,24 +16,30 @@ import org.jetbrains.kotlin.wasm.ir.*
 class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
     val functions =
         ReferencableAndDefinable<IrFunctionSymbol, WasmFunction>()
-    val globals =
+    val globalFields =
         ReferencableAndDefinable<IrFieldSymbol, WasmGlobal>()
+    val globalVTables =
+        ReferencableAndDefinable<IrClassSymbol, WasmGlobal>()
+    val globalClassITables =
+        ReferencableAndDefinable<IrClassSymbol, WasmGlobal>()
     val functionTypes =
         ReferencableAndDefinable<IrFunctionSymbol, WasmFunctionType>()
     val gcTypes =
         ReferencableAndDefinable<IrClassSymbol, WasmTypeDeclaration>()
+    val vTableGcTypes =
+        ReferencableAndDefinable<IrClassSymbol, WasmTypeDeclaration>()
+    val classITableGcType =
+        ReferencableAndDefinable<IrClassSymbol, WasmTypeDeclaration>()
+    val classITableInterfaceSlot =
+        ReferencableAndDefinable<IrClassSymbol, Int>()
     val classIds =
         ReferencableElements<IrClassSymbol, Int>()
     val interfaceId =
         ReferencableElements<IrClassSymbol, Int>()
-    val virtualFunctionId =
-        ReferencableElements<IrFunctionSymbol, Int>()
-    val signatureId =
-        ReferencableElements<WasmSignature, Int>()
     val stringLiteralId =
         ReferencableElements<String, Int>()
 
-    val tagFuncType = WasmFunctionType(
+    private val tagFuncType = WasmFunctionType(
         listOf(
             WasmRefNullType(WasmHeapType.Type(gcTypes.reference(irBuiltIns.throwableClass)))
         ),
@@ -42,34 +47,7 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
     )
     val tag = WasmTag(tagFuncType)
 
-
-    val classes = mutableListOf<IrClassSymbol>()
-    val interfaces = mutableListOf<IrClassSymbol>()
-    val virtualFunctions = mutableListOf<IrSimpleFunctionSymbol>()
-    val signatures = LinkedHashSet<WasmSignature>()
-
-    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 typeInfo = ReferencableAndDefinable<IrClassSymbol, ConstantDataElement>()
 
     val exports = mutableListOf<WasmExport<*>>()
 
@@ -82,7 +60,7 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
     val initFunctions = mutableListOf<FunWithPriority>()
 
     val scratchMemAddr = WasmSymbol<Int>()
-    val scratchMemSizeInBytes = 65_536
+    private val scratchMemSizeInBytes = 65_536
 
     open class ReferencableElements<Ir, Wasm : Any> {
         val unbound = mutableMapOf<Ir, WasmSymbol<Wasm>>()
@@ -117,9 +95,13 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
     @OptIn(ExperimentalUnsignedTypes::class)
     fun linkWasmCompiledFragments(): WasmModule {
         bind(functions.unbound, functions.defined)
-        bind(globals.unbound, globals.defined)
-
+        bind(globalFields.unbound, globalFields.defined)
+        bind(globalVTables.unbound, globalVTables.defined)
         bind(gcTypes.unbound, gcTypes.defined)
+        bind(vTableGcTypes.unbound, vTableGcTypes.defined)
+        bind(classITableGcType.unbound, classITableGcType.defined)
+        bind(classITableInterfaceSlot.unbound, classITableInterfaceSlot.defined)
+        bind(globalClassITables.unbound, globalClassITables.defined)
 
         // Associate function types to a single canonical function type
         val canonicalFunctionTypes =
@@ -139,13 +121,6 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
             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
-        }
-
         val stringDataSectionStart = currentDataSectionAddress
         val stringDataSectionBytes = mutableListOf<Byte>()
         val stringAddrs = mutableMapOf<String, Int>()
@@ -163,107 +138,12 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
         currentDataSectionAddress += scratchMemSizeInBytes
 
         bind(classIds.unbound, klassIds)
-        bind(referencedClassITableAddresses.unbound, interfaceTableAddresses)
         bind(stringLiteralId.unbound, stringAddrs)
-        bindIndices(virtualFunctionId.unbound, virtualFunctions)
-        bindIndices(signatureId.unbound, signatures.toList())
-        bindIndices(interfaceId.unbound, interfaces)
-
-        val interfaceImplementationIds = mutableMapOf<InterfaceImplementation, Int>()
-        val numberOfInterfaceImpls = mutableMapOf<IrClassSymbol, Int>()
-        for (interfaceImplementation in interfaceImplementationsMethods.keys) {
-            val prev = numberOfInterfaceImpls.getOrPut(interfaceImplementation.irInterface) { 0 }
-            interfaceImplementationIds[interfaceImplementation] = prev
-            numberOfInterfaceImpls[interfaceImplementation.irInterface] = prev + 1
-        }
-
-        bind(referencedInterfaceImplementationId.unbound, interfaceImplementationIds)
-        bind(interfaceMethodTables.unbound, interfaceMethodTables.defined)
+        interfaceId.unbound.onEachIndexed { index, entry -> entry.value.bind(index) }
 
         val data = typeInfo.buildData(address = { klassIds.getValue(it) }) +
-                definedClassITableData.buildData(address = { interfaceTableAddresses.getValue(it) }) +
                 WasmData(WasmDataMode.Active(0, stringDataSectionStart), stringDataSectionBytes.toByteArray())
 
-        val logTypeInfo = false
-        if (logTypeInfo) {
-            println("Signatures: ")
-            for ((index, signature: WasmSignature) in signatures.withIndex()) {
-                println("  -- $index $signature")
-            }
-
-            println("Interfaces: ")
-            for ((index, iface: IrClassSymbol) in interfaces.withIndex()) {
-                println("  -- $index ${iface.owner.fqNameWhenAvailable}")
-            }
-
-            println("Interfaces implementations: ")
-            for ((interfaceImpl, index: Int) in interfaceImplementationIds) {
-                println(
-                    "  -- $index" +
-                            " Interface: ${interfaceImpl.irInterface.owner.fqNameWhenAvailable}" +
-                            " Class: ${interfaceImpl.irClass.owner.fqNameWhenAvailable}"
-                )
-            }
-
-
-            println("Virtual functions: ")
-            for ((index, vf: IrSimpleFunctionSymbol) in virtualFunctions.withIndex()) {
-                println("  -- $index ${vf.owner.fqNameWhenAvailable}")
-            }
-
-            println(
-                ConstantDataStruct("typeInfo", typeInfo.elements).dump("", 0)
-            )
-        }
-
-        val table = WasmTable(
-            limits = WasmLimits(virtualFunctions.size.toUInt(), virtualFunctions.size.toUInt()),
-            elementType = WasmFuncRef,
-        )
-
-        val offsetExpr = mutableListOf<WasmInstr>()
-        WasmIrExpressionBuilder(offsetExpr).buildConstI32(0)
-
-        val elements = WasmElement(
-            WasmFuncRef,
-            values = virtualFunctions.map {
-                WasmTable.Value.Function(functions.defined.getValue(it))
-            },
-            WasmElement.Mode.Active(table, offsetExpr)
-        )
-
-        val interfaceTableElementsLists = interfaceMethodTables.defined.keys.associateWith {
-            mutableMapOf<Int, WasmSymbol<WasmFunction>?>()
-        }
-
-        for ((ii: InterfaceImplementation, implId: Int) in interfaceImplementationIds) {
-            for ((interfaceFunction: IrFunctionSymbol, wasmFunction: WasmSymbol<WasmFunction>?) in interfaceImplementationsMethods[ii]!!) {
-                interfaceTableElementsLists[interfaceFunction]!![implId] = wasmFunction
-            }
-        }
-
-        val interfaceTableElements = interfaceTableElementsLists.map { (interfaceFunction, methods) ->
-            val methodTable = interfaceMethodTables.defined[interfaceFunction]!!
-            val type = methodTable.elementType
-            val functions = MutableList(methods.size) { idx ->
-                val wasmFunc = methods[idx]
-                val expression = buildWasmExpression {
-                    if (wasmFunc != null) {
-                        buildInstr(WasmOp.REF_FUNC, WasmImmediate.FuncIdx(wasmFunc))
-                    } else {
-                        //DCE could remove implementation from class, so we should to put a stub into method implementations table
-                        buildRefNull(type.getHeapType())
-                    }
-                }
-                WasmTable.Value.Expression(expression)
-            }
-            WasmElement(
-                type,
-                values = functions,
-                WasmElement.Mode.Active(methodTable, offsetExpr)
-            )
-        }
-
         val masterInitFunctionType = WasmFunctionType(emptyList(), emptyList())
         val masterInitFunction = WasmFunction.Defined("__init", WasmSymbol(masterInitFunctionType))
         with(WasmIrExpressionBuilder(masterInitFunction.instructions)) {
@@ -273,11 +153,6 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
         }
         exports += WasmExport.Function("__init", masterInitFunction)
 
-        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()))
@@ -297,21 +172,30 @@ class WasmCompiledModuleFragment(val irBuiltIns: IrBuiltIns) {
             }
         }
 
-        val sortedGcTypes = gcTypes.elements.sortedBy(::wasmTypeDeclarationOrderKey)
+        val typeDeclarations = mutableListOf<WasmTypeDeclaration>()
+        typeDeclarations.addAll(vTableGcTypes.elements)
+        typeDeclarations.addAll(gcTypes.elements)
+        typeDeclarations.addAll(classITableGcType.elements.distinct())
+        typeDeclarations.sortBy(::wasmTypeDeclarationOrderKey)
+
+        val globals = mutableListOf<WasmGlobal>()
+        globals.addAll(globalFields.elements)
+        globals.addAll(globalVTables.elements)
+        globals.addAll(globalClassITables.elements.distinct())
 
         val module = WasmModule(
             functionTypes = canonicalFunctionTypes.values.toList() + tagFuncType + masterInitFunctionType,
-            gcTypes = sortedGcTypes,
+            gcTypes = typeDeclarations,
             gcTypesInRecursiveGroup = true,
             importsInOrder = importedFunctions,
             importedFunctions = importedFunctions,
             definedFunctions = functions.elements.filterIsInstance<WasmFunction.Defined>() + masterInitFunction,
-            tables = listOf(table) + interfaceMethodTables.elements,
+            tables = emptyList(),
             memories = listOf(memory),
-            globals = globals.elements,
+            globals = globals,
             exports = exports,
             startFunction = null,  // Module is initialized via export call
-            elements = listOf(elements) + interfaceTableElements,
+            elements = emptyList(),
             data = data,
             tags = listOf(tag)
         )
@@ -338,18 +222,6 @@ private fun irSymbolDebugDump(symbol: Any?): String =
         else -> symbol.toString()
     }
 
-fun <IrSymbolType> bindIndices(
-    unbound: Map<IrSymbolType, WasmSymbol<Int>>,
-    ordered: List<IrSymbolType>
-) {
-    unbound.forEach { (irSymbol, wasmSymbol) ->
-        val index = ordered.indexOf(irSymbol)
-        if (index == -1)
-            error("Can't link symbol with indices ${irSymbolDebugDump(irSymbol)}")
-        wasmSymbol.bind(index)
-    }
-}
-
 inline fun WasmCompiledModuleFragment.ReferencableAndDefinable<IrClassSymbol, ConstantDataElement>.buildData(address: (IrClassSymbol) -> Int): List<WasmData> {
     return elements.map {
         val id = address(wasmToIr.getValue(it))
@@ -359,11 +231,6 @@ inline fun WasmCompiledModuleFragment.ReferencableAndDefinable<IrClassSymbol, Co
     }
 }
 
-data class InterfaceImplementation(
-    val irInterface: IrClassSymbol,
-    val irClass: IrClassSymbol
-)
-
 fun alignUp(x: Int, alignment: Int): Int {
     assert(alignment and (alignment - 1) == 0) { "power of 2 expected" }
     return (x + alignment - 1) and (alignment - 1).inv()

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

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.wasm.ir.WasmInstr
 import org.jetbrains.kotlin.wasm.ir.WasmLocal
 
 enum class LoopLabelType { BREAK, CONTINUE }
+enum class SyntheticLocalType { IS_INTERFACE_PARAMETER }
 
 interface WasmFunctionCodegenContext : WasmBaseCodegenContext {
     val irFunction: IrFunction
@@ -20,6 +21,7 @@ interface WasmFunctionCodegenContext : WasmBaseCodegenContext {
     fun defineLocal(irValueDeclaration: IrValueSymbol)
     fun referenceLocal(irValueDeclaration: IrValueSymbol): WasmLocal
     fun referenceLocal(index: Int): WasmLocal
+    fun referenceLocal(type: SyntheticLocalType): WasmLocal
 
     fun defineLoopLevel(irLoop: IrLoop, labelType: LoopLabelType, level: Int)
     fun referenceLoopLevel(irLoop: IrLoop, labelType: LoopLabelType): Int

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

@@ -27,6 +27,7 @@ class WasmFunctionCodegenContextImpl(
         get() = 0
 
     private val wasmLocals = LinkedHashMap<IrValueSymbol, WasmLocal>()
+    private val wasmSyntheticLocals = LinkedHashMap<SyntheticLocalType, WasmLocal>()
     private val loopLevels = LinkedHashMap<Pair<IrLoop, LoopLabelType>, Int>()
 
     override fun defineLocal(irValueDeclaration: IrValueSymbol) {
@@ -52,6 +53,17 @@ class WasmFunctionCodegenContextImpl(
         return wasmFunction.locals[index]
     }
 
+    override fun referenceLocal(type: SyntheticLocalType): WasmLocal = wasmSyntheticLocals.getOrPut(type) {
+        WasmLocal(
+            wasmFunction.locals.size,
+            type.name,
+            WasmRefNullType(WasmHeapType.Type(referenceGcType(backendContext.irBuiltIns.anyClass))),
+            isParameter = false
+        ).also {
+            wasmFunction.locals += it
+        }
+    }
+
     override fun defineLoopLevel(irLoop: IrLoop, labelType: LoopLabelType, level: Int) {
         val loopKey = Pair(irLoop, labelType)
         assert(loopKey !in loopLevels) { "Redefinition of loop" }

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

@@ -5,10 +5,7 @@
 
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
-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.ir.symbols.*
 import org.jetbrains.kotlin.wasm.ir.*
 
 /**
@@ -16,27 +13,16 @@ import org.jetbrains.kotlin.wasm.ir.*
  */
 interface WasmModuleCodegenContext : WasmBaseCodegenContext {
     fun defineFunction(irFunction: IrFunctionSymbol, wasmFunction: WasmFunction)
-    fun defineGlobal(irField: IrFieldSymbol, wasmGlobal: WasmGlobal)
+    fun defineGlobalField(irField: IrFieldSymbol, wasmGlobal: WasmGlobal)
+    fun defineGlobalVTable(irClass: IrClassSymbol, wasmGlobal: WasmGlobal)
+    fun defineGlobalClassITable(irClass: IrClassSymbol, wasmGlobal: WasmGlobal)
     fun defineGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration)
+    fun defineVTableGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration)
     fun defineFunctionType(irFunction: IrFunctionSymbol, wasmFunctionType: WasmFunctionType)
-    fun defineInterfaceMethodTable(irFunction: IrFunctionSymbol, wasmTable: WasmTable)
     fun addJsFun(importName: String, jsCode: String)
 
     fun registerInitFunction(wasmFunction: WasmFunction, priority: String)
     fun addExport(wasmExport: WasmExport<*>)
 
-    fun registerVirtualFunction(irFunction: IrSimpleFunctionSymbol)
-    fun registerInterface(irInterface: IrClassSymbol)
-    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

@@ -6,19 +6,12 @@
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
-import org.jetbrains.kotlin.backend.wasm.lower.WasmSignature
-import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
-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.ir.symbols.*
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.defaultType
-import org.jetbrains.kotlin.ir.types.getClass
 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.*
 
@@ -70,10 +63,6 @@ class WasmModuleCodegenContextImpl(
         wasmFragment.typeInfo.define(irClass, typeInfo)
     }
 
-    override fun generateInterfaceTable(irClass: IrClassSymbol, table: ConstantDataElement) {
-        wasmFragment.definedClassITableData.define(irClass, table)
-    }
-
     override fun registerInitFunction(wasmFunction: WasmFunction, priority: String) {
         wasmFragment.initFunctions += WasmCompiledModuleFragment.FunWithPriority(wasmFunction, priority)
     }
@@ -82,51 +71,34 @@ class WasmModuleCodegenContextImpl(
         wasmFragment.exports += wasmExport
     }
 
-    override fun registerVirtualFunction(irFunction: IrSimpleFunctionSymbol) {
-        wasmFragment.virtualFunctions += irFunction
-    }
-
-    override fun registerInterface(irInterface: IrClassSymbol) {
-        wasmFragment.interfaces += irInterface
-    }
-
-    override fun registerClass(irClass: IrClassSymbol) {
-        wasmFragment.classes += irClass
-    }
-
     override fun defineFunction(irFunction: IrFunctionSymbol, wasmFunction: WasmFunction) {
         wasmFragment.functions.define(irFunction, wasmFunction)
     }
 
-    override fun defineGlobal(irField: IrFieldSymbol, wasmGlobal: WasmGlobal) {
-        wasmFragment.globals.define(irField, wasmGlobal)
+    override fun defineGlobalField(irField: IrFieldSymbol, wasmGlobal: WasmGlobal) {
+        wasmFragment.globalFields.define(irField, wasmGlobal)
+    }
+
+    override fun defineGlobalVTable(irClass: IrClassSymbol, wasmGlobal: WasmGlobal) {
+        wasmFragment.globalVTables.define(irClass, wasmGlobal)
+    }
+
+    override fun defineGlobalClassITable(irClass: IrClassSymbol, wasmGlobal: WasmGlobal) {
+        wasmFragment.globalClassITables.define(irClass, wasmGlobal)
     }
 
     override fun defineGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration) {
         wasmFragment.gcTypes.define(irClass, wasmType)
     }
 
+    override fun defineVTableGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration) {
+        wasmFragment.vTableGcTypes.define(irClass, wasmType)
+    }
+
     override fun defineFunctionType(irFunction: IrFunctionSymbol, wasmFunctionType: WasmFunctionType) {
         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) {
@@ -139,18 +111,59 @@ class WasmModuleCodegenContextImpl(
             )
         }
 
+    private val interfaceMetadataCache = mutableMapOf<IrClassSymbol, InterfaceMetadata>()
+    override fun getInterfaceMetadata(irClass: IrClassSymbol): InterfaceMetadata =
+        interfaceMetadataCache.getOrPut(irClass) { InterfaceMetadata(irClass.owner, backendContext.irBuiltIns) }
+
     override fun referenceFunction(irFunction: IrFunctionSymbol): WasmSymbol<WasmFunction> =
         wasmFragment.functions.reference(irFunction)
 
-    override fun referenceGlobal(irField: IrFieldSymbol): WasmSymbol<WasmGlobal> =
-        wasmFragment.globals.reference(irField)
+    override fun referenceGlobalField(irField: IrFieldSymbol): WasmSymbol<WasmGlobal> =
+        wasmFragment.globalFields.reference(irField)
 
-    override fun referenceGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration> {
+    override fun referenceGlobalVTable(irClass: IrClassSymbol): WasmSymbol<WasmGlobal> =
+        wasmFragment.globalVTables.reference(irClass)
+
+    override fun referenceGlobalClassITable(irClass: IrClassSymbol): WasmSymbol<WasmGlobal> =
+        wasmFragment.globalClassITables.reference(irClass)
+
+    private fun referenceNonNothingType(
+        irClass: IrClassSymbol,
+        from: WasmCompiledModuleFragment.ReferencableAndDefinable<IrClassSymbol, WasmTypeDeclaration>
+    ): WasmSymbol<WasmTypeDeclaration> {
         val type = irClass.defaultType
         require(!type.isNothing()) {
             "Can't reference Nothing type"
         }
-        return wasmFragment.gcTypes.reference(irClass)
+        return from.reference(irClass)
+    }
+
+    override fun referenceGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration> =
+        referenceNonNothingType(irClass, wasmFragment.gcTypes)
+
+    override fun referenceVTableGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration> =
+        referenceNonNothingType(irClass, wasmFragment.vTableGcTypes)
+
+    override fun referenceClassITableGcType(irClass: IrClassSymbol): WasmSymbol<WasmTypeDeclaration> =
+        referenceNonNothingType(irClass, wasmFragment.classITableGcType)
+
+    override fun defineClassITableGcType(irClass: IrClassSymbol, wasmType: WasmTypeDeclaration) {
+        wasmFragment.classITableGcType.define(irClass, wasmType)
+    }
+
+    override fun isAlreadyDefinedClassITableGcType(irClass: IrClassSymbol): Boolean =
+        wasmFragment.classITableGcType.defined.keys.contains(irClass)
+
+    override fun referenceClassITableInterfaceSlot(irClass: IrClassSymbol): WasmSymbol<Int> {
+        val type = irClass.defaultType
+        require(!type.isNothing()) {
+            "Can't reference Nothing type"
+        }
+        return wasmFragment.classITableInterfaceSlot.reference(irClass)
+    }
+
+    override fun defineClassITableInterfaceSlot(irClass: IrClassSymbol, slot: Int) {
+        wasmFragment.classITableInterfaceSlot.define(irClass, slot)
     }
 
     override fun referenceFunctionType(irFunction: IrFunctionSymbol): WasmSymbol<WasmFunctionType> =
@@ -159,35 +172,14 @@ 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> {
         return wasmFragment.interfaceId.reference(irInterface)
     }
 
-    override fun referenceVirtualFunctionId(irFunction: IrSimpleFunctionSymbol): WasmSymbol<Int> {
-        if (irFunction.owner.modality == Modality.ABSTRACT)
-            error("Abstract functions are not stored in table")
-        return wasmFragment.virtualFunctionId.reference(irFunction)
-    }
-
-    override fun referenceSignatureId(signature: WasmSignature): WasmSymbol<Int> {
-        wasmFragment.signatures.add(signature)
-        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)
-        val fieldId = metadata.fields.indexOf(field)
+        val fieldId = metadata.fields.indexOf(field) + 2 //Implicit vtable and vtable field
         return WasmSymbol(fieldId)
     }
 
@@ -195,4 +187,5 @@ class WasmModuleCodegenContextImpl(
         wasmFragment.jsFuns +=
             WasmCompiledModuleFragment.JsCodeSnippet(importName = importName, jsCode = jsCode)
     }
-}
+}
+

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

@@ -6,9 +6,16 @@
 package org.jetbrains.kotlin.backend.wasm.ir2wasm
 
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
-import org.jetbrains.kotlin.ir.declarations.IrDeclaration
+import org.jetbrains.kotlin.backend.wasm.utils.DisjointUnions
+import org.jetbrains.kotlin.backend.wasm.utils.getWasmArrayAnnotation
+import org.jetbrains.kotlin.backend.wasm.utils.isAbstractOrSealed
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
-import org.jetbrains.kotlin.ir.declarations.IrPackageFragment
+import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
+import org.jetbrains.kotlin.ir.util.isAnnotationClass
+import org.jetbrains.kotlin.ir.util.isInterface
+import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 
 class WasmModuleFragmentGenerator(
@@ -16,28 +23,49 @@ class WasmModuleFragmentGenerator(
     wasmModuleFragment: WasmCompiledModuleFragment,
     allowIncompleteImplementations: Boolean,
 ) {
+    private val hierarchyDisjointUnions = DisjointUnions<IrClassSymbol>()
+
     private val declarationGenerator =
         DeclarationGenerator(
             WasmModuleCodegenContextImpl(
                 backendContext,
                 wasmModuleFragment,
             ),
-            allowIncompleteImplementations
+            allowIncompleteImplementations,
+            hierarchyDisjointUnions,
         )
 
+    private val interfaceCollector = object : IrElementVisitorVoid {
+        override fun visitElement(element: IrElement) { }
+
+        override fun visitClass(declaration: IrClass) {
+            if (declaration.isAnnotationClass) return
+            if (declaration.isExternal) return
+            if (declaration.getWasmArrayAnnotation() != null) return
+            if (declaration.isInterface) return
+            if (declaration.isAbstractOrSealed) return
+
+            val classMetadata = declarationGenerator.context.getClassMetadata(declaration.symbol)
+            if (classMetadata.interfaces.isNotEmpty()) {
+                hierarchyDisjointUnions.addUnion(classMetadata.interfaces.map { it.symbol })
+            }
+        }
+    }
+
+    fun collectInterfaceTables(irModuleFragment: IrModuleFragment) {
+        acceptVisitor(irModuleFragment, interfaceCollector)
+        hierarchyDisjointUnions.compress()
+    }
+
     fun generateModule(irModuleFragment: IrModuleFragment) {
+        acceptVisitor(irModuleFragment, declarationGenerator)
+    }
+
+    private fun acceptVisitor(irModuleFragment: IrModuleFragment, visitor: IrElementVisitorVoid) {
         for (irFile in irModuleFragment.files) {
-            generatePackageFragment(irFile)
+            for (irDeclaration in irFile.declarations) {
+                irDeclaration.acceptVoid(visitor)
+            }
         }
     }
-
-    fun generatePackageFragment(irPackageFragment: IrPackageFragment) {
-        for (irDeclaration in irPackageFragment.declarations) {
-            generateDeclaration(irDeclaration)
-        }
-    }
-
-    fun generateDeclaration(irDeclaration: IrDeclaration) {
-        irDeclaration.acceptVoid(declarationGenerator)
-    }
 }

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/lower/FieldInitializersLowering.kt

@@ -9,7 +9,6 @@ import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.lower.at
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
-import org.jetbrains.kotlin.backend.wasm.ir2wasm.getRuntimeClass
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.builders.irSetField
 import org.jetbrains.kotlin.ir.declarations.IrField

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/lower/WasmTypeOperatorLowering.kt

@@ -101,9 +101,6 @@ class WasmBaseTypeOperatorTransformer(val context: WasmBackendContext) : IrEleme
     private val IrType.eraseToClassOrInterface: IrClass
         get() = this.erasedUpperBound ?: builtIns.anyClass.owner
 
-    private val IrType.eraseToClass: IrClass
-        get() = this.getRuntimeClass ?: builtIns.anyClass.owner
-
     private fun generateTypeCheck(
         valueProvider: () -> IrExpression,
         toType: IrType
@@ -302,19 +299,16 @@ class WasmBaseTypeOperatorTransformer(val context: WasmBackendContext) : IrEleme
     }
 
     private fun generateIsInterface(argument: IrExpression, toType: IrType): IrExpression {
-        val interfaceId = builder.irCall(symbols.wasmInterfaceId).apply {
-            putTypeArgument(0, toType)
-        }
         return builder.irCall(symbols.isInterface).apply {
             putValueArgument(0, argument)
-            putValueArgument(1, interfaceId)
+            putTypeArgument(0, toType)
         }
     }
 
     private fun generateIsSubClass(argument: IrExpression, toType: IrType): IrExpression {
         val fromType = argument.type
-        val fromTypeErased = fromType.eraseToClass
-        val toTypeErased = toType.eraseToClass
+        val fromTypeErased = fromType.getRuntimeClass(context.irBuiltIns)
+        val toTypeErased = toType.getRuntimeClass(context.irBuiltIns)
         if (fromTypeErased.isSubclassOf(toTypeErased)) {
             return builder.irTrue()
         }

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/utils/DisjointUnions.kt

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2010-2022 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.backend.wasm.utils
+
+class DisjointUnions<T> {
+    private val leafParents = mutableMapOf<T, Node>()
+    private var dirty: Boolean = false
+
+    private inner class Node(var rank: Int = 0, val leafs: MutableList<T> = mutableListOf()) {
+        var parent: Node? = null
+        override fun toString(): String = "${if (parent == null) "ROOT " else ""}Node with ${leafs.size} leafs and $rank rank"
+    }
+
+    private fun findRoot(node: T): Node? =
+        leafParents[node]?.let { findRoot(it) }
+
+    private fun findRoot(node: Node, pathWeight: Int = 0): Node {
+        val strictParent = node.parent ?: return node
+        val currentWeight = pathWeight + node.leafs.size
+        val foundRoot = findRoot(strictParent, currentWeight)
+
+        if (foundRoot != node) {
+            val leafs = node.leafs
+            node.rank -= currentWeight
+            check(node.rank >= 0)
+            foundRoot.leafs.addAll(leafs)
+            leafs.clear()
+            node.parent = foundRoot
+        }
+
+        return foundRoot
+    }
+
+    private fun addToRoot(leaf: T, root: Node) {
+        leafParents[leaf] = root
+        root.rank++
+        root.leafs.add(leaf)
+    }
+
+    private fun mergeRoots(root1: Node, root2: Node): Node {
+        if (root1 == root2) return root1
+        require(root1.parent == null && root2.parent == null) { "Merge is possible only for root nodes" }
+        if (root2.parent == root1) return root1
+        if (root1.parent == root2) return root2
+
+        val rootToMove: Node
+        val newParentRoot: Node
+        if (root1.rank > root2.rank) {
+            rootToMove = root2
+            newParentRoot = root1
+        } else {
+            rootToMove = root1
+            newParentRoot = root2
+        }
+
+        rootToMove.parent = newParentRoot
+
+        val leafs = rootToMove.leafs
+        newParentRoot.rank += leafs.size
+        rootToMove.rank -= leafs.size
+        check(rootToMove.rank >= 0)
+        newParentRoot.leafs.addAll(leafs)
+        leafs.clear()
+
+        return newParentRoot
+    }
+
+    fun addUnion(elements: List<T>) {
+        var currentRoot: Node? = null
+        dirty = true
+        for (leaf in elements) {
+            val strictRoot = leafParents[leaf]
+            if (strictRoot == null) {
+                currentRoot = currentRoot?.let(::findRoot) ?: Node()
+                addToRoot(leaf, currentRoot)
+            } else {
+                val leafRoot = findRoot(strictRoot)
+                currentRoot = if (currentRoot != null) mergeRoots(currentRoot, leafRoot) else leafRoot
+            }
+        }
+    }
+
+    fun compress() {
+        if (dirty) {
+            leafParents.keys.forEach(::findRoot)
+            dirty = false
+        }
+    }
+
+    operator fun contains(element: T): Boolean =
+        leafParents.containsKey(element)
+
+    operator fun get(element: T): List<T> {
+        require(!dirty) { "Call compress before getting union" }
+        val root = findRoot(element)
+        require(root != null) { "Element not contains in any union" }
+        check(root.rank == root.leafs.size) { "Invalid tree state after compress" }
+        return root.leafs
+    }
+}

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/utils/Utils.kt

@@ -5,7 +5,9 @@
 
 package org.jetbrains.kotlin.backend.wasm.utils
 
+import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.ir.IrBuiltIns
+import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.expressions.IrTry
 
 // Backed codegen can only handle try/catch in canonical form.
@@ -16,6 +18,9 @@ import org.jetbrains.kotlin.ir.expressions.IrTry
 //   ...exprs
 // }
 // no-finally
-fun IrTry.isCanonical(builtIns: IrBuiltIns) =
+internal fun IrTry.isCanonical(builtIns: IrBuiltIns) =
     catches.singleOrNull()?.catchParameter?.symbol?.owner?.type == builtIns.throwableType &&
-    finallyExpression == null
+    finallyExpression == null
+
+internal val IrClass.isAbstractOrSealed
+    get() = modality == Modality.ABSTRACT || modality == Modality.SEALED

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

@@ -14,9 +14,8 @@ internal const val TYPE_INFO_TYPE_PACKAGE_NAME_PRT_OFFSET = TYPE_INFO_TYPE_PACKA
 internal const val TYPE_INFO_TYPE_SIMPLE_NAME_LENGTH_OFFSET = TYPE_INFO_TYPE_PACKAGE_NAME_PRT_OFFSET + TYPE_INFO_ELEMENT_SIZE
 internal const val TYPE_INFO_TYPE_SIMPLE_NAME_PRT_OFFSET = TYPE_INFO_TYPE_SIMPLE_NAME_LENGTH_OFFSET + TYPE_INFO_ELEMENT_SIZE
 internal const val TYPE_INFO_SUPER_TYPE_OFFSET = TYPE_INFO_TYPE_SIMPLE_NAME_PRT_OFFSET + TYPE_INFO_ELEMENT_SIZE
-internal const val TYPE_INFO_ITABLE_PTR_OFFSET = TYPE_INFO_SUPER_TYPE_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 const val TYPE_INFO_ITABLE_SIZE_OFFSET = TYPE_INFO_SUPER_TYPE_OFFSET + TYPE_INFO_ELEMENT_SIZE
+internal const val TYPE_INFO_ITABLE_OFFSET = TYPE_INFO_ITABLE_SIZE_OFFSET + TYPE_INFO_ELEMENT_SIZE
 
 internal class TypeInfoData(val typeId: Int, val isInterface: Boolean, val packageName: String, val typeName: String)
 
@@ -33,45 +32,24 @@ internal fun getTypeInfoTypeDataByPtr(typeInfoPtr: Int): TypeInfoData {
 internal fun getSuperTypeId(typeInfoPtr: Int): Int =
     wasm_i32_load(typeInfoPtr + TYPE_INFO_SUPER_TYPE_OFFSET)
 
-internal fun getVtablePtr(obj: Any): Int =
-    obj.typeInfo + TYPE_INFO_VTABLE_OFFSET
-
-internal fun getVtableLength(obj: Any): Int =
-    wasm_i32_load(obj.typeInfo + TYPE_INFO_VTABLE_LENGTH_OFFSET)
-
-internal fun getItablePtr(obj: Any): Int =
-    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 getVirtualMethodId(obj: Any, virtualFunctionSlot: Int): Int {
-    val vtablePtr = getVtablePtr(obj)
-    val methodIdPtr = vtablePtr + virtualFunctionSlot * TYPE_INFO_ELEMENT_SIZE
-    return wasm_i32_load(methodIdPtr)
-}
-
-// Returns -1 if obj does not implement interface
-internal fun getInterfaceImplId(obj: Any, interfaceId: Int): Int {
-    val interfaceListSizePtr = getItablePtr(obj)
-    val interfaceListPtr = interfaceListSizePtr + TYPE_INFO_ELEMENT_SIZE
-    val interfaceListSize = wasm_i32_load(interfaceListSizePtr)
+internal fun isInterfaceById(obj: Any, interfaceId: Int): Boolean {
+    val interfaceListSize = wasm_i32_load(obj.typeInfo + TYPE_INFO_ITABLE_SIZE_OFFSET)
+    val interfaceListPtr = obj.typeInfo + TYPE_INFO_ITABLE_OFFSET
 
     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)
+            return true
         }
         interfaceSlot++
     }
-
-    return -1
+    return false
 }
 
-internal fun isInterface(obj: Any, interfaceId: Int): Boolean {
-    return getInterfaceImplId(obj, interfaceId) != -1
-}
+@ExcludedFromCodegen
+internal fun <T> isInterface(obj: Any): Boolean =
+    implementedAsIntrinsic
 
 @ExcludedFromCodegen
 internal fun <T> wasmClassId(): Int =

libraries/stdlib/wasm/src/kotlin/reflect/KClassImpl.kt

@@ -7,7 +7,7 @@ package kotlin.reflect.wasm.internal
 import kotlin.reflect.*
 import kotlin.wasm.internal.TypeInfoData
 import kotlin.wasm.internal.getSuperTypeId
-import kotlin.wasm.internal.isInterface
+import kotlin.wasm.internal.isInterfaceById
 
 internal object NothingKClassImpl : KClass<Nothing> {
     override val simpleName: String = "Nothing"
@@ -38,7 +38,7 @@ internal class KClassImpl<T : Any>(private val typeData: TypeInfoData) : KClass<
     }
 
     override fun isInstance(value: Any?): Boolean = value?.let {
-        if (typeData.isInterface) isInterface(it, typeData.typeId) else checkSuperTypeInstance(it)
+        if (typeData.isInterface) isInterfaceById(it, typeData.typeId) else checkSuperTypeInstance(it)
     } ?: false
 
     override fun equals(other: Any?): Boolean =

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

@@ -374,6 +374,7 @@ enum class WasmOp(
     BR_ON_CAST("br_on_cast", 0xFB_42, listOf(LABEL_IDX)),
 
     BR_ON_CAST_FAIL("br_on_cast_fail", 0xfb43, listOf(LABEL_IDX)),
+    BR_ON_CAST_STATIC_FAIL("br_on_cast_static_fail", 0xfb47, listOf(LABEL_IDX, STRUCT_TYPE_IDX)),
 
     REF_IS_FUNC("ref.is_func", 0xfb50),
     REF_IS_DATA("ref.is_data", 0xfb51),

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

@@ -34,15 +34,19 @@ abstract class WasmExpressionBuilder {
     }
 
     @Suppress("UNUSED_PARAMETER")
-    fun buildBlock(label: String?, resultType: WasmType? = null) {
+    inline fun buildBlock(label: String?, resultType: WasmType? = null, body: (Int) -> Unit) {
         numberOfNestedBlocks++
         buildInstr(WasmOp.BLOCK, WasmImmediate.BlockType.Value(resultType))
+        body(numberOfNestedBlocks)
+        buildEnd()
     }
 
     @Suppress("UNUSED_PARAMETER")
-    fun buildLoop(label: String?, resultType: WasmType? = null) {
+    inline fun buildLoop(label: String?, resultType: WasmType? = null, body: (Int) -> Unit) {
         numberOfNestedBlocks++
         buildInstr(WasmOp.LOOP, WasmImmediate.BlockType.Value(resultType))
+        body(numberOfNestedBlocks)
+        buildEnd()
     }
 
     @Suppress("UNUSED_PARAMETER")
@@ -60,10 +64,21 @@ abstract class WasmExpressionBuilder {
         buildInstr(WasmOp.END)
     }
 
-    fun buildBr(absoluteBlockLevel: Int) {
+
+    fun buildBrInstr(brOp: WasmOp, absoluteBlockLevel: Int) {
         val relativeLevel = numberOfNestedBlocks - absoluteBlockLevel
         assert(relativeLevel >= 0) { "Negative relative block index" }
-        buildInstr(WasmOp.BR, WasmImmediate.LabelIdx(relativeLevel))
+        buildInstr(brOp, WasmImmediate.LabelIdx(relativeLevel))
+    }
+
+    fun buildBrInstr(brOp: WasmOp, absoluteBlockLevel: Int, symbol: WasmSymbolReadOnly<WasmTypeDeclaration>) {
+        val relativeLevel = numberOfNestedBlocks - absoluteBlockLevel
+        assert(relativeLevel >= 0) { "Negative relative block index" }
+        buildInstr(brOp, WasmImmediate.LabelIdx(relativeLevel), WasmImmediate.TypeIdx(symbol))
+    }
+
+    fun buildBr(absoluteBlockLevel: Int) {
+        buildBrInstr(WasmOp.BR, absoluteBlockLevel)
     }
 
     fun buildThrow(tagIdx: Int) {
@@ -81,9 +96,7 @@ abstract class WasmExpressionBuilder {
     }
 
     fun buildBrIf(absoluteBlockLevel: Int) {
-        val relativeLevel = numberOfNestedBlocks - absoluteBlockLevel
-        assert(relativeLevel >= 0) { "Negative relative block index" }
-        buildInstr(WasmOp.BR_IF, WasmImmediate.LabelIdx(relativeLevel))
+        buildBrInstr(WasmOp.BR_IF, absoluteBlockLevel)
     }
 
     fun buildCall(symbol: WasmSymbol<WasmFunction>) {
@@ -126,7 +139,7 @@ abstract class WasmExpressionBuilder {
     }
 
     fun buildStructNew(struct: WasmSymbol<WasmTypeDeclaration>) {
-        buildInstr(WasmOp.STRUCT_NEW_WITH_RTT, WasmImmediate.GcType(struct))
+        buildInstr(WasmOp.STRUCT_NEW, WasmImmediate.GcType(struct))
     }
 
     fun buildStructSet(struct: WasmSymbol<WasmTypeDeclaration>, fieldId: WasmSymbol<Int>) {
@@ -142,8 +155,8 @@ abstract class WasmExpressionBuilder {
         buildInstr(WasmOp.REF_CAST)
     }
 
-    fun buildRefCastStatic(type: WasmSymbolReadOnly<WasmTypeDeclaration>) {
-        buildInstr(WasmOp.REF_CAST_STATIC, WasmImmediate.TypeIdx(type))
+    fun buildRefCastStatic(toType: WasmSymbolReadOnly<WasmTypeDeclaration>) {
+        buildInstr(WasmOp.REF_CAST_STATIC, WasmImmediate.TypeIdx(toType))
     }
 
     fun buildRefNull(type: WasmHeapType) {

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

@@ -21,7 +21,6 @@ class WasmIrExpressionBuilder(
         }
     }
 
-
     override var numberOfNestedBlocks: Int = 0
         set(value) {
             assert(value >= 0) { "end without matching block" }