--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core/src/org/graalvm/compiler/core/target/Backend.java	Fri Mar 16 11:26:05 2018 +0000
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core/src/org/graalvm/compiler/core/target/Backend.java	Fri Mar 16 22:59:32 2018 -0700
@@ -178,7 +178,7 @@
      * @param method the method compiled to produce {@code compiledCode} or {@code null} if the
      *            input to {@code compResult} was not a {@link ResolvedJavaMethod}
      * @param compilationRequest the compilation request or {@code null}
-     * @param compilationResult the code to be compiled
+     * @param compilationResult the code to be installed
      * @param predefinedInstalledCode a pre-allocated {@link InstalledCode} object to use as a
      *            reference to the installed code. If {@code null}, a new {@link InstalledCode}
      *            object will be created.
@@ -204,12 +204,13 @@
         }
         try (DebugContext.Scope s2 = debug.scope("CodeInstall", debugContext);
                         DebugContext.Activation a = debug.activate()) {
-            preCodeInstallationTasks(tasks, compilationResult);
 
             InstalledCode installedCode;
             try {
+                preCodeInstallationTasks(tasks, compilationResult, predefinedInstalledCode);
                 CompiledCode compiledCode = createCompiledCode(method, compilationRequest, compilationResult);
                 installedCode = getProviders().getCodeCache().installCode(method, compiledCode, predefinedInstalledCode, speculationLog, isDefault);
+                assert predefinedInstalledCode == null || installedCode == predefinedInstalledCode;
             } catch (Throwable t) {
                 failCodeInstallationTasks(tasks, t);
                 throw t;
@@ -229,9 +230,9 @@
         }
     }
 
-    private static void preCodeInstallationTasks(CodeInstallationTask[] tasks, CompilationResult compilationResult) {
+    private static void preCodeInstallationTasks(CodeInstallationTask[] tasks, CompilationResult compilationResult, InstalledCode predefinedInstalledCode) {
         for (CodeInstallationTask task : tasks) {
-            task.preProcess(compilationResult);
+            task.preProcess(compilationResult, predefinedInstalledCode);
         }
     }
 
@@ -305,23 +306,29 @@
     public abstract static class CodeInstallationTask {
         /**
          * Task to run before code installation.
+         *
+         * @param compilationResult the code about to be installed
+         * @param predefinedInstalledCode a pre-allocated {@link InstalledCode} object that will be
+         *            used as a reference to the installed code. May be {@code null}.
+         *
          */
-        @SuppressWarnings("unused")
-        public void preProcess(CompilationResult compilationResult) {
+        public void preProcess(CompilationResult compilationResult, InstalledCode predefinedInstalledCode) {
         }
 
         /**
          * Task to run after the code is installed.
+         *
+         * @param installedCode a reference to the installed code
          */
-        @SuppressWarnings("unused")
         public void postProcess(InstalledCode installedCode) {
         }
 
         /**
          * Invoked after {@link #preProcess} when code installation fails.
+         *
+         * @param cause the cause of the installation failure
          */
-        @SuppressWarnings("unused")
-        public void installFailed(Throwable t) {
+        public void installFailed(Throwable cause) {
         }
     }