scala-js · sjrd · Aug 30, 2024 · Jun 24, 2024 · Jun 24, 2024 · Jun 24, 2024
diff --git a/Jenkinsfile b/Jenkinsfile
@@ -431,6 +431,20 @@ def Tasks = [
         'set scalaJSLinkerConfig in $testSuite.v$v ~= (_.withOptimizer(false))' \
         'set scalaJSStage in Global := FullOptStage' \
         $testSuite$v/test &&
+    sbtretry ++$scala \
+        'set Global/enableWasmEverywhere := true' \
+        'set scalaJSLinkerConfig in $testSuite.v$v ~= makeCompliant' \
+        $testSuite$v/test &&
+    sbtretry ++$scala \
+        'set Global/enableWasmEverywhere := true' \
+        'set scalaJSLinkerConfig in $testSuite.v$v ~= makeCompliant' \
+        'set scalaJSStage in Global := FullOptStage' \
+        $testSuite$v/test &&
+    sbtretry ++$scala \
+        'set Global/enableWasmEverywhere := true' \
+        'set scalaJSLinkerConfig in $testSuite.v$v ~= makeCompliant' \
+        'set scalaJSLinkerConfig in $testSuite.v$v ~= (_.withOptimizer(false))' \
+        $testSuite$v/test &&
     sbtretry ++$scala \
         'set Global/enableWasmEverywhere := true' \
         testingExample$v/testHtml &&

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/WebAssemblyLinkerBackend.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/WebAssemblyLinkerBackend.scala
@@ -36,17 +36,6 @@ final class WebAssemblyLinkerBackend(config: LinkerBackendImpl.Config)
     coreSpec.moduleKind == ModuleKind.ESModule,
     s"The WebAssembly backend only supports ES modules; was ${coreSpec.moduleKind}."
   )
-  require(
-    coreSpec.semantics.asInstanceOfs == CheckedBehavior.Unchecked &&
-    coreSpec.semantics.arrayIndexOutOfBounds == CheckedBehavior.Unchecked &&
-    coreSpec.semantics.arrayStores == CheckedBehavior.Unchecked &&
-    coreSpec.semantics.negativeArraySizes == CheckedBehavior.Unchecked &&
-    coreSpec.semantics.nullPointers == CheckedBehavior.Unchecked &&
-    coreSpec.semantics.stringIndexOutOfBounds == CheckedBehavior.Unchecked &&
-    coreSpec.semantics.moduleInit == CheckedBehavior.Unchecked,
-    "The WebAssembly backend currently only supports CheckedBehavior.Unchecked semantics; " +
-    s"was ${coreSpec.semantics}."
-  )
   require(
     coreSpec.semantics.strictFloats,
     "The WebAssembly backend only supports strict float semantics."

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/wasmemitter/ClassEmitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/wasmemitter/ClassEmitter.scala
@@ -20,6 +20,7 @@ import org.scalajs.ir.OriginalName.NoOriginalName
 import org.scalajs.ir.Trees._
 import org.scalajs.ir.Types._
 
+import org.scalajs.linker.interface.CheckedBehavior
 import org.scalajs.linker.interface.unstable.RuntimeClassNameMapperImpl
 import org.scalajs.linker.standard.{CoreSpec, LinkedClass, LinkedTopLevelExport}
 
@@ -37,6 +38,7 @@ import WasmContext._
 
 class ClassEmitter(coreSpec: CoreSpec) {
   import ClassEmitter._
+  import coreSpec.semantics
 
   def genClassDef(clazz: LinkedClass)(implicit ctx: WasmContext): Unit = {
     val classInfo = ctx.getClassInfo(clazz.className)
@@ -373,6 +375,12 @@ class ClassEmitter(coreSpec: CoreSpec) {
         genCloneFunction(clazz)
     }
 
+    // Generate cast functions
+    if (clazz.hasInstanceTests && semantics.asInstanceOfs != CheckedBehavior.Unchecked) {
+      if (className != ObjectClass)
+        genClassCastFunction(clazz)
+    }
+
     // Generate the module accessor
     if (clazz.kind == ClassKind.ModuleClass && clazz.hasInstances) {
       val heapType = watpe.HeapType(genTypeID.forClass(clazz.className))
@@ -387,6 +395,17 @@ class ClassEmitter(coreSpec: CoreSpec) {
       )
       ctx.addGlobal(global)
 
+      if (semantics.moduleInit != CheckedBehavior.Unchecked) {
+        val initFlagGlobal = wamod.Global(
+          genGlobalID.forModuleInitFlag(className),
+          makeDebugName(ns.ModuleInitFlag, className),
+          isMutable = true,
+          watpe.Int32,
+          wa.Expr(List(wa.I32Const(0)))
+        )
+        ctx.addGlobal(initFlagGlobal)
+      }
+
       genModuleAccessor(clazz)
     }
   }
@@ -408,7 +427,7 @@ class ClassEmitter(coreSpec: CoreSpec) {
       case None    => genTypeID.typeData
       case Some(s) => genTypeID.forVTable(s.name)
     }
-    val structType = watpe.StructType(CoreWasmLib.typeDataStructFields ::: vtableFields)
+    val structType = watpe.StructType(ctx.coreLib.typeDataStructFields ::: vtableFields)
     val subType = watpe.SubType(
       typeID,
       makeDebugName(ns.VTable, className),
@@ -522,6 +541,50 @@ class ClassEmitter(coreSpec: CoreSpec) {
     fb.buildAndAddToModule()
   }
 
+  /** Generate the cast function for an interface.
+   *
+   *  When `asInstanceOfs` are checked, the expression `asInstanceOf[<interface>]`
+   *  will be compiled to a CALL to the function generated by this method.
+   */
+  private def genInterfaceCastFunction(clazz: LinkedClass)(
+      implicit ctx: WasmContext): Unit = {
+    assert(clazz.kind == ClassKind.Interface)
+
+    val className = clazz.className
+    val resultType = TypeTransformer.transformClassType(className, nullable = true)
+
+    val fb = new FunctionBuilder(
+      ctx.moduleBuilder,
+      genFunctionID.asInstance(ClassType(className, nullable = true)),
+      makeDebugName(ns.AsInstance, className),
+      clazz.pos
+    )
+    val objParam = fb.addParam("obj", watpe.RefType.anyref)
+    fb.setResultType(resultType)
+
+    fb.block() { successLabel =>
+      // Succeed if null
+      fb += wa.LocalGet(objParam)
+      fb += wa.BrOnNull(successLabel)
+
+      // Succeed if the instance test succeeds
+      fb += wa.Call(genFunctionID.instanceTest(className))
+      fb += wa.BrIf(successLabel)
+
+      // If we get here, it's a CCE
+      fb += wa.LocalGet(objParam)
+      fb += wa.GlobalGet(genGlobalID.forVTable(className))
+      fb += wa.Call(genFunctionID.classCastException)
+      fb += wa.Unreachable
+    }
+
+    fb += wa.LocalGet(objParam)
+    if (resultType != watpe.RefType.anyref)
+      fb += wa.RefCast(resultType)
+
+    fb.buildAndAddToModule()
+  }
+
   private def genNewDefaultFunc(clazz: LinkedClass)(implicit ctx: WasmContext): Unit = {
     val className = clazz.name.name
     val classInfo = ctx.getClassInfo(className)
@@ -598,6 +661,56 @@ class ClassEmitter(coreSpec: CoreSpec) {
     fb.buildAndAddToModule()
   }
 
+  /** Generate the cast function for a class.
+   *
+   *  When `asInstanceOfs` are checked, the expression `asInstanceOf[<class>]`
+   *  will be compiled to a CALL to the function generated by this method.
+   */
+  private def genClassCastFunction(clazz: LinkedClass)(implicit ctx: WasmContext): Unit = {
+    val className = clazz.className
+
+    val resultType = TypeTransformer.transformClassType(className, nullable = true)
+
+    val fb = new FunctionBuilder(
+      ctx.moduleBuilder,
+      genFunctionID.asInstance(ClassType(clazz.className, nullable = true)),
+      makeDebugName(ns.AsInstance, className),
+      clazz.pos
+    )
+    val objParam = fb.addParam("obj", watpe.RefType.anyref)
+    fb.setResultType(resultType)
+
+    fb.block(resultType) { successLabel =>
+      fb += wa.LocalGet(objParam)
+
+      if (className == SpecialNames.JLNumberClass) {
+        /* jl.Number is special, because it is the only non-Object *class*
+         * that is an  ancestor of a hijacked class.
+         */
+        fb += wa.BrOnCast(successLabel, watpe.RefType.anyref,
+            watpe.RefType.nullable(genTypeID.forClass(SpecialNames.JLNumberClass)))
+
+        /* The `obj` still on the stack will be used for:
+         * a) the result in the true case
+         * b) consistency with non-Number in the false case
+         */
+
+        fb += wa.LocalGet(objParam)
+        fb += wa.Call(genFunctionID.typeTest(DoubleRef))
+        fb += wa.BrIf(successLabel)
+      } else {
+        fb += wa.BrOnCast(successLabel, watpe.RefType.anyref, resultType)
+      }
+
+      // If we get here, it's a CCE -- `obj` is still on the stack
+      fb += wa.GlobalGet(genGlobalID.forVTable(className))
+      fb += wa.Call(genFunctionID.classCastException)
+      fb += wa.Unreachable
+    }
+
+    fb.buildAndAddToModule()
+  }
+
   private def genModuleAccessor(clazz: LinkedClass)(implicit ctx: WasmContext): Unit = {
     assert(clazz.kind == ClassKind.ModuleClass)
 
@@ -613,7 +726,10 @@ class ClassEmitter(coreSpec: CoreSpec) {
       makeDebugName(ns.ModuleAccessor, className),
       clazz.pos
     )
-    fb.setResultType(resultType)
+    if (semantics.moduleInit == CheckedBehavior.Compliant)
+      fb.setResultType(resultType.toNullable)
+    else
+      fb.setResultType(resultType)
 
     val instanceLocal = fb.addLocal("instance", resultType)
 
@@ -622,6 +738,30 @@ class ClassEmitter(coreSpec: CoreSpec) {
       fb += wa.GlobalGet(globalInstanceID)
       fb += wa.BrOnNonNull(nonNullLabel)
 
+      // check ongoing initialization
+      if (semantics.moduleInit != CheckedBehavior.Unchecked) {
+        val initFlagID = genGlobalID.forModuleInitFlag(className)
+
+        // if being initialized
+        fb += wa.GlobalGet(initFlagID)
+        fb.ifThen() {
+          if (semantics.moduleInit == CheckedBehavior.Compliant) {
+            // then, return null
+            fb += wa.RefNull(watpe.HeapType.None)
+            fb += wa.Return
+          } else {
+            // then, throw
+            fb += wa.GlobalGet(genGlobalID.forVTable(className))
+            fb += wa.Call(genFunctionID.throwModuleInitError)
+            fb += wa.Unreachable // for clarity; technically redundant since the stacks align
+          }
+        }
+
+        // mark as being initialized
+        fb += wa.I32Const(1)
+        fb += wa.GlobalSet(initFlagID)
+      }
+
       // create an instance and call its constructor
       fb += wa.Call(genFunctionID.newDefault(className))
       fb += wa.LocalTee(instanceLocal)
@@ -685,8 +825,11 @@ class ClassEmitter(coreSpec: CoreSpec) {
       itableType
     )
 
-    if (clazz.hasInstanceTests)
+    if (clazz.hasInstanceTests) {
       genInterfaceInstanceTest(clazz)
+      if (semantics.asInstanceOfs != CheckedBehavior.Unchecked)
+        genInterfaceCastFunction(clazz)
+    }
   }
 
   private def genJSClass(clazz: LinkedClass)(implicit ctx: WasmContext): Unit = {
@@ -1258,10 +1401,12 @@ object ClassEmitter {
     // Shared with JS backend -- className
     val ModuleAccessor = UTF8String("m.")
     val ModuleInstance = UTF8String("n.")
+    val ModuleInitFlag = UTF8String("ni.")
     val JSClassAccessor = UTF8String("a.")
     val JSClassValueCache = UTF8String("b.")
     val TypeData = UTF8String("d.")
     val IsInstance = UTF8String("is.")
+    val AsInstance = UTF8String("as.")
 
     // Shared with JS backend -- string
     val TopLevelExport = UTF8String("e.")