diff --git a/.travis.yml b/.travis.yml
index a2afc38..972df16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,9 +4,9 @@ scala:
   - 2.11.12
   - 2.12.8
 jdk:
-  - oraclejdk8
+  - openjdk8
 env:
-  - SCALAJS_VERSION=1.0.0-M7
+  - SCALAJS_VERSION=1.0.0-M8
 script:
   - ./scripts/assemble-cli.sh $SCALAJS_VERSION $TRAVIS_SCALA_VERSION
 cache:
diff --git a/appveyor.yml b/appveyor.yml
index 7f22792..9c54ab3 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -2,7 +2,7 @@ version: '{build}'
 os: Windows Server 2012
 environment:
   global:
-    SCALAJS_VERSION: 1.0.0-M7
+    SCALAJS_VERSION: 1.0.0-M8
   matrix:
     - SCALA_VERSION: 2.11.12
     - SCALA_VERSION: 2.12.8
diff --git a/build.sbt b/build.sbt
index b1db035..9f8238c 100644
--- a/build.sbt
+++ b/build.sbt
@@ -33,7 +33,7 @@ inThisBuild(Def.settings(
   scalaVersion := crossScalaVersions.value.head,
   scalacOptions ++= Seq("-deprecation", "-feature", "-Xfatal-warnings"),
 
-  scalaJSVersion := "1.0.0-M7",
+  scalaJSVersion := "1.0.0-M8",
   scalaJSBinaryVersion := binaryScalaJSVersion(scalaJSVersion.value),
 
   scalaJSScalaVersions := Seq(
diff --git a/project/build.properties b/project/build.properties
index 394cb75..c0bab04 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.0.4
+sbt.version=1.2.8
diff --git a/src/main/scala/org/scalajs/cli/Scalajsld.scala b/src/main/scala/org/scalajs/cli/Scalajsld.scala
index 6809f46..945dc55 100644
--- a/src/main/scala/org/scalajs/cli/Scalajsld.scala
+++ b/src/main/scala/org/scalajs/cli/Scalajsld.scala
@@ -11,8 +11,6 @@ package org.scalajs.cli
 
 import org.scalajs.ir.ScalaJSVersions
 
-import org.scalajs.io._
-
 import org.scalajs.logging._
 
 import org.scalajs.linker._
@@ -22,7 +20,7 @@ import CheckedBehavior.Compliant
 
 import scala.collection.immutable.Seq
 
-import scala.concurrent.Await
+import scala.concurrent.{Await, Future}
 import scala.concurrent.duration.Duration
 import scala.concurrent.ExecutionContext.Implicits.global
 
@@ -149,8 +147,7 @@ object Scalajsld {
     }
 
     for (options <- parser.parse(args, Options())) {
-      val classpath = options.stdLib.toList ++ options.cp
-      val irContainers = FileScalaJSIRContainer.fromClasspath(classpath)
+      val classpath = (options.stdLib.toList ++ options.cp).map(_.toPath())
       val moduleInitializers = options.moduleInitializers
 
       val semantics =
@@ -172,13 +169,14 @@ object Scalajsld {
 
       val linker = StandardLinker(config)
       val logger = new ScalaConsoleLogger(options.logLevel)
-      val outFile = new WritableFileVirtualBinaryFile(options.output)
+      val outFile = new WritableFileVirtualBinaryFile(options.output.toPath())
       val output = LinkerOutput(outFile)
-      val cache = (new IRFileCache).newCache
 
-      val future = linker.link(cache.cached(irContainers), moduleInitializers,
-          output, logger)
-      Await.result(future, Duration.Inf)
+      val result = FileScalaJSIRContainer
+        .fromClasspath(classpath)
+        .flatMap(containers => Future.traverse(containers)(_.sjsirFiles).map(_.flatten))
+        .flatMap(linker.link(_, moduleInitializers, output, logger))
+      Await.result(result, Duration.Inf)
     }
   }
 }
diff --git a/src/main/scala/org/scalajs/cli/Scalajsp.scala b/src/main/scala/org/scalajs/cli/Scalajsp.scala
index f2d2d7f..36d2766 100644
--- a/src/main/scala/org/scalajs/cli/Scalajsp.scala
+++ b/src/main/scala/org/scalajs/cli/Scalajsp.scala
@@ -9,18 +9,24 @@
 
 package org.scalajs.cli
 
+import org.scalajs.ir.Definitions
 import org.scalajs.ir.ScalaJSVersions
 import org.scalajs.ir.Trees.{Tree, ClassDef}
 import org.scalajs.ir.Printers.IRTreePrinter
 
-import org.scalajs.io._
-
 import org.scalajs.linker.irio._
 
 import scala.collection.immutable.Seq
 
+import scala.concurrent._
+import scala.concurrent.duration.Duration
+import scala.concurrent.ExecutionContext.Implicits.global
+
+import scala.util.{Failure, Success}
+
 import java.io.{Console => _, _}
 import java.util.zip.{ZipFile, ZipEntry}
+import java.nio.file.Path
 
 object Scalajsp {
 
@@ -63,7 +69,7 @@ object Scalajsp {
         readFromFile(fileName)
       }
 
-      displayFileContent(vfile, options)
+      displayFileContent(Await.result(vfile, Duration.Inf), options)
     }
   }
 
@@ -76,7 +82,8 @@ object Scalajsp {
 
   private def displayFileContent(vfile: VirtualScalaJSIRFile,
       opts: Options): Unit = {
-    new IRTreePrinter(stdout).print(vfile.tree)
+    val tree = Await.result(vfile.tree, Duration.Inf)
+    new IRTreePrinter(stdout).print(tree)
     stdout.write('\n')
     stdout.flush()
   }
@@ -91,24 +98,49 @@ object Scalajsp {
     throw new AssertionError("unreachable")
   }
 
-  private def readFromFile(fileName: String): VirtualScalaJSIRFile = {
+  private def readFromFile(fileName: String): Future[VirtualScalaJSIRFile] = {
     val file = new File(fileName)
 
-    if (!file.exists)
+    if (!file.exists) {
       fail(s"No such file: $fileName")
-    else if (!file.canRead)
+    } else if (!file.canRead) {
       fail(s"Unable to read file: $fileName")
-    else
-      new FileVirtualScalaJSIRFile(file, file.getName)
+    } else {
+      for {
+        container <- FileScalaJSIRContainer.fromSingleFile(file.toPath())
+        sjsirFiles <- container.sjsirFiles
+      } yield {
+        sjsirFiles.head
+      }
+    }
   }
 
-  private def readFromJar(jar: File, name: String): VirtualScalaJSIRFile = {
+  private def readFromJar(jar: File, name: String): Future[VirtualScalaJSIRFile] = {
     /* This could be more efficient if we only read the relevant entry. But it
      * probably does not matter, and this implementation is very simple.
      */
-    val jarFile = new FileVirtualJarScalaJSIRContainer(jar)
-    jarFile.sjsirFiles.find(_.relativePath == name).getOrElse {
-      fail(s"No such file in jar: $name")
+
+    def findRequestedClass(sjsirFiles: List[VirtualScalaJSIRFile]): Future[VirtualScalaJSIRFile] = {
+      Future.traverse(sjsirFiles) { ir =>
+        ir.entryPointsInfo.map { i =>
+          if (i.encodedName == name || Definitions.decodeClassName(i.encodedName) == name) Success(Some(ir))
+          else Success(None)
+        }.recover { case t => Failure(t) }
+      }.map { irs =>
+        irs.collectFirst {
+          case Success(Some(f)) => f
+        }.getOrElse {
+          fail(s"No such class in jar: $name")
+        }
+      }
+    }
+
+    for {
+      jarFile <- FileScalaJSIRContainer.fromJar(jar.toPath())
+      sjsirFiles <- jarFile.sjsirFiles
+      requestedFile <- findRequestedClass(sjsirFiles)
+    } yield {
+      requestedFile
     }
   }