[Wasm] WasmExport implementation

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

@@ -6,6 +6,8 @@
 package org.jetbrains.kotlin.backend.wasm.dce
 
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
+import org.jetbrains.kotlin.backend.wasm.ir2wasm.isExported
+import org.jetbrains.kotlin.backend.wasm.utils.getWasmExportNameIfWasmExport
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.backend.js.dce.DceDumpNameCache
 import org.jetbrains.kotlin.ir.backend.js.utils.*
@@ -51,7 +53,7 @@ private fun buildRoots(modules: List<IrModuleFragment>, context: WasmBackendCont
 
     modules.onAllFiles {
         declarations.forEach { declaration ->
-            if (declaration.isJsExport()) {
+            if (declaration is IrFunction && declaration.isExported()) {
                 declaration.acceptVoid(declarationsCollector)
             }
         }

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

@@ -207,5 +207,5 @@ internal class WasmUsefulDeclarationProcessor(
         }
     }
 
-    override fun isExported(declaration: IrDeclaration): Boolean = declaration.isJsExport()
+    override fun isExported(declaration: IrDeclaration): Boolean = (declaration is IrFunction && declaration.isExported())
 }

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

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.ir.types.getClass
 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.FqName
 import org.jetbrains.kotlin.name.parentOrNull
 import org.jetbrains.kotlin.wasm.ir.*
 import org.jetbrains.kotlin.wasm.ir.source.location.SourceLocation
@@ -182,11 +183,16 @@ class DeclarationGenerator(
         if (initPriority != null)
             context.registerInitFunction(function, initPriority)
 
-        if (declaration.isExported()) {
+        val nameIfExported = when {
+            declaration.isJsExport() -> declaration.getJsNameOrKotlinName().identifier
+            else -> declaration.getWasmExportNameIfWasmExport()
+        }
+
+        if (nameIfExported != null) {
             context.addExport(
                 WasmExport.Function(
                     field = function,
-                    name = declaration.getJsNameOrKotlinName().identifier
+                    name = nameIfExported
                 )
             )
         }
@@ -500,8 +506,7 @@ fun IrFunction.getEffectiveValueParameters(): List<IrValueParameter> {
 }
 
 fun IrFunction.isExported(): Boolean =
-    isJsExport()
+    isJsExport() || getWasmExportNameIfWasmExport() != null
-
 
 fun generateConstExpression(
     expression: IrConst<*>,

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

@@ -12,13 +12,13 @@ import org.jetbrains.kotlin.backend.common.lower.DeclarationIrBuilder
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
 import org.jetbrains.kotlin.backend.wasm.ir2wasm.isBuiltInWasmRefType
-import org.jetbrains.kotlin.backend.wasm.ir2wasm.isExported
 import org.jetbrains.kotlin.backend.wasm.ir2wasm.isExternalType
 import org.jetbrains.kotlin.backend.wasm.ir2wasm.toJsStringLiteral
 import org.jetbrains.kotlin.backend.wasm.utils.getJsFunAnnotation
 import org.jetbrains.kotlin.backend.wasm.utils.getWasmImportDescriptor
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.ir.backend.js.utils.getJsNameOrKotlinName
+import org.jetbrains.kotlin.ir.backend.js.utils.isJsExport
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.*
 import org.jetbrains.kotlin.ir.declarations.*
@@ -49,7 +49,7 @@ class JsInteropFunctionsLowering(val context: WasmBackendContext) : DeclarationT
     override fun transformFlat(declaration: IrDeclaration): List<IrDeclaration>? {
         if (declaration.isFakeOverride) return null
         if (declaration !is IrSimpleFunction) return null
-        val isExported = declaration.isExported()
+        val isExported = declaration.isJsExport()
         val isExternal = declaration.isExternal || declaration.getJsFunAnnotation() != null
         if (declaration.isPropertyAccessor) return null
         if (declaration.parent !is IrPackageFragment) return null

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

@@ -61,3 +61,10 @@ fun IrAnnotationContainer.getJsFunAnnotation(): String? =
 
 fun IrAnnotationContainer.getJsPrimitiveType(): String? =
     getAnnotation(FqName("kotlin.wasm.internal.JsPrimitive"))?.getSingleConstStringArgument()
+
+@Suppress("UNCHECKED_CAST")
+fun IrFunction.getWasmExportNameIfWasmExport(): String? {
+    val annotation = getAnnotation(FqName("kotlin.wasm.WasmExport")) ?: return null
+    if (annotation.valueArgumentsCount == 0) return name.identifier
+    return (annotation.getValueArgument(0) as? IrConst<String>)?.value ?: name.identifier
+}

compiler/testData/codegen/boxWasmJsInterop/wasmExport.kt

@@ -0,0 +1,19 @@
+// TARGET_BACKEND: WASM
+
+import kotlin.wasm.WasmExport
+
+@WasmExport
+fun exportDefaultName(): String = "some string"
+
+fun checkDefaultName(): Int = js("typeof wasmExports.exportDefaultName() === 'object'")
+
+@WasmExport("exportOverriddenName")
+fun exportWithName(): String = "some string"
+
+fun checkOverriddenName(): Int = js("typeof wasmExports.exportOverriddenName() === 'object'")
+
+fun box(): String {
+    if (checkDefaultName() != 1) return "checkDefaultName fail"
+    if (checkOverriddenName() != 1) return "checkOverriddenName fail"
+    return "OK"
+}

compiler/testData/diagnostics/wasmTests/wasmInterop/wasmExport.kt

@@ -0,0 +1,23 @@
+import kotlin.wasm.WasmExport
+
+<!WASM_EXPORT_ON_EXTERNAL_DECLARATION!>@WasmExport("a")
+external fun foo0(): Unit<!>
+
+<!WASM_EXPORT_ON_EXTERNAL_DECLARATION!>@WasmExport("a")
+fun foo1(): Int = js("42")<!>
+
+class C() {
+    <!NESTED_WASM_EXPORT!>@WasmExport("a")
+    fun foo2(): Int = 42<!>
+}
+
+@WasmExport("a")
+fun foo3(): Int = 42
+
+@WasmExport()
+fun foo4(): Int = 42
+
+<!JS_AND_WASM_EXPORTS_ON_SAME_DECLARATION!>@OptIn(kotlin.js.ExperimentalJsExport::class)
+@JsExport()
+@WasmExport()
+fun foo6(): Int = 42<!>

libraries/stdlib/wasm/src/kotlin/wasm/Annotations.kt

@@ -11,11 +11,23 @@ package kotlin.wasm
  *
  * Can only be used on top-level external functions.
  *
- * In JavaScript environment,
+ * The annotated function will be imported into Wasm module without type adapters.
- * function will be imported from ES module without type adapters.
  */
 @Target(AnnotationTarget.FUNCTION)
 public annotation class WasmImport(
     val module: String,
     val name: String = ""
+)
+
+/**
+ * Exports a function with the given optional [name].
+ * The declaration name will be used if the [name] argument is not provided.
+ *
+ * Can only be used on top-level non-external functions.
+ *
+ * The annotated function will be exported from Wasm module without type adapters.
+ */
+@Target(AnnotationTarget.FUNCTION)
+public annotation class WasmExport(
+    val name: String = ""
 )

wasm/wasm.frontend/src/org/jetbrains/kotlin/wasm/resolve/WasmPlatformConfigurator.kt

@@ -32,6 +32,7 @@ object WasmPlatformConfigurator : PlatformConfiguratorBase(
         WasmImportAnnotationChecker,
         WasmJsFunAnnotationChecker,
         WasmJsInteropTypesChecker,
+        WasmInteropTypesChecker,
     ),
     additionalCallCheckers = listOf(
         JsModuleCallChecker,

wasm/wasm.frontend/src/org/jetbrains/kotlin/wasm/resolve/diagnostics/DefaultErrorMessagesWasm.kt

@@ -25,6 +25,10 @@ private val DIAGNOSTIC_FACTORY_TO_RENDERER by lazy {
             Renderers.RENDER_TYPE
         )
 
+        put(ErrorsWasm.NESTED_WASM_EXPORT, "Only top-level functions can be exported with @WasmExport")
+        put(ErrorsWasm.WASM_EXPORT_ON_EXTERNAL_DECLARATION, "Functions annotated with @WasmExport must not be external")
+        put(ErrorsWasm.JS_AND_WASM_EXPORTS_ON_SAME_DECLARATION, "Cannot use @WasmExport and @JsExport for same function")
+
         put(ErrorsWasm.NESTED_WASM_IMPORT, "Only top-level functions can be imported with @WasmImport")
         put(ErrorsWasm.WASM_IMPORT_ON_NON_EXTERNAL_DECLARATION, "Functions annotated with @WasmImport must be external")
         put(ErrorsWasm.WASM_IMPORT_PARAMETER_DEFAULT_VALUE, "Default parameter values are not supported with @WasmImport")

wasm/wasm.frontend/src/org/jetbrains/kotlin/wasm/resolve/diagnostics/ErrorsWasm.java

@@ -19,6 +19,10 @@ public interface ErrorsWasm {
     DiagnosticFactory2<PsiElement, String, KotlinType>
             WRONG_JS_INTEROP_TYPE = DiagnosticFactory2.create(ERROR, PositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT);
 
+    DiagnosticFactory0<PsiElement> NESTED_WASM_EXPORT = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> WASM_EXPORT_ON_EXTERNAL_DECLARATION = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> JS_AND_WASM_EXPORTS_ON_SAME_DECLARATION = DiagnosticFactory0.create(ERROR);
+
     DiagnosticFactory0<PsiElement> NESTED_WASM_IMPORT = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> WASM_IMPORT_ON_NON_EXTERNAL_DECLARATION = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> WASM_IMPORT_PARAMETER_DEFAULT_VALUE = DiagnosticFactory0.create(ERROR);

wasm/wasm.frontend/src/org/jetbrains/kotlin/wasm/resolve/diagnostics/WasmInteropTypesChecker.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.wasm.resolve.diagnostics
+
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.resolve.DescriptorUtils
+import org.jetbrains.kotlin.resolve.checkers.DeclarationChecker
+import org.jetbrains.kotlin.resolve.checkers.DeclarationCheckerContext
+import org.jetbrains.kotlin.resolve.descriptorUtil.isEffectivelyExternal
+import org.jetbrains.kotlin.wasm.util.hasValidJsCodeBody
+
+// TODO: Implement in K2: KT-56849
+object WasmInteropTypesChecker : DeclarationChecker {
+    override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
+        if (descriptor !is FunctionDescriptor) return
+
+        if (!descriptor.annotations.hasAnnotation(FqName("kotlin.wasm.WasmExport"))) return
+
+        val trace = context.trace
+        val bindingContext = trace.bindingContext
+
+        if (descriptor.annotations.hasAnnotation(FqName("kotlin.js.JsExport"))) {
+            val reportOn = descriptor.findPsi() ?: declaration
+            trace.report(ErrorsWasm.JS_AND_WASM_EXPORTS_ON_SAME_DECLARATION.on(reportOn))
+        }
+
+        if (descriptor.isEffectivelyExternal() || descriptor.hasValidJsCodeBody(bindingContext)) {
+            val reportOn = descriptor.findPsi() ?: declaration
+            trace.report(ErrorsWasm.WASM_EXPORT_ON_EXTERNAL_DECLARATION.on(reportOn))
+        }
+
+        if (!DescriptorUtils.isTopLevelDeclaration(descriptor)) {
+            val reportOn = descriptor.findPsi() ?: declaration
+            trace.report(ErrorsWasm.NESTED_WASM_EXPORT.on(reportOn))
+        }
+    }
+}

wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/FirWasmCodegenWasmJsInteropTestGenerated.java

@@ -151,6 +151,12 @@ public class FirWasmCodegenWasmJsInteropTestGenerated extends AbstractFirWasmCod
         runTest("compiler/testData/codegen/boxWasmJsInterop/vararg.kt");
     }
 
+    @Test
+    @TestMetadata("wasmExport.kt")
+    public void testWasmExport() throws Exception {
+        runTest("compiler/testData/codegen/boxWasmJsInterop/wasmExport.kt");
+    }
+
     @Test
     @TestMetadata("wasmImport.kt")
     public void testWasmImport() throws Exception {

wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/K1WasmCodegenWasmJsInteropTestGenerated.java

@@ -151,6 +151,12 @@ public class K1WasmCodegenWasmJsInteropTestGenerated extends AbstractK1WasmCodeg
         runTest("compiler/testData/codegen/boxWasmJsInterop/vararg.kt");
     }
 
+    @Test
+    @TestMetadata("wasmExport.kt")
+    public void testWasmExport() throws Exception {
+        runTest("compiler/testData/codegen/boxWasmJsInterop/wasmExport.kt");
+    }
+
     @Test
     @TestMetadata("wasmImport.kt")
     public void testWasmImport() throws Exception {

wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/diagnostics/DiagnosticsWasmTestGenerated.java

@@ -85,6 +85,12 @@ public class DiagnosticsWasmTestGenerated extends AbstractDiagnosticsWasmTest {
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/wasmTests/wasmInterop"), Pattern.compile("^(.+)\\.kt$"), null, true);
         }
 
+        @Test
+        @TestMetadata("wasmExport.kt")
+        public void testWasmExport() throws Exception {
+            runTest("compiler/testData/diagnostics/wasmTests/wasmInterop/wasmExport.kt");
+        }
+
         @Test
         @TestMetadata("wasmImport.kt")
         public void testWasmImport() throws Exception {