From 8ee7e8124afcc8bd62a44bdf3896dbe2da8c29bf Mon Sep 17 00:00:00 2001
From: Joel Dice <joel.dice@gmail.com>
Date: Thu, 15 Jan 2015 17:08:40 -0700
Subject: [PATCH] fix broken interpreter build due to out-of-order class
 initialization

When we initialize the vtables for bootstrap Java classes such as
java.lang.NullPointerException (i.e. classes which the VM has built-in
knowledge of), we assign the superclass's vtable to any class which
has no declared virtual methods of its own.  However, that vtable will
be null if we haven't initialized the superclass yet.  Therefore, we
must order this process such that no class is initialized until after
all its superclasses.
---
 src/tools/type-generator/main.cpp | 17 +++++++++++++++--
 test/NullPointer.java             |  6 ++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/tools/type-generator/main.cpp b/src/tools/type-generator/main.cpp
index 32dcf6f7f0..c981d13194 100644
--- a/src/tools/type-generator/main.cpp
+++ b/src/tools/type-generator/main.cpp
@@ -1408,8 +1408,20 @@ void writeInitializations(Output* out, Module& module)
   }
 }
 
-void writeJavaInitialization(Output* out, Class* cl)
+void writeJavaInitialization(Output* out,
+                             Class* cl,
+                             std::set<Class*>& alreadyInited)
 {
+  if (alreadyInited.find(cl) != alreadyInited.end()) {
+    return;
+  }
+
+  alreadyInited.insert(cl);
+
+  if (cl->super) {
+    writeJavaInitialization(out, cl->super, alreadyInited);
+  }
+
   out->write("bootJavaClass(t, Gc::");
   out->write(capitalize(cl->name));
   out->write("Type, ");
@@ -1436,10 +1448,11 @@ void writeJavaInitialization(Output* out, Class* cl)
 
 void writeJavaInitializations(Output* out, Module& module)
 {
+  std::set<Class*> alreadyInited;
   for (const auto p : module.classes) {
     Class* cl = p.second;
     if (cl->javaName.size()) {
-      writeJavaInitialization(out, cl);
+      writeJavaInitialization(out, cl, alreadyInited);
     }
   }
 }
diff --git a/test/NullPointer.java b/test/NullPointer.java
index 6c6e5c7b50..8d3abdc6fa 100644
--- a/test/NullPointer.java
+++ b/test/NullPointer.java
@@ -16,6 +16,12 @@ public class NullPointer {
   }
 
   public static void main(String[] args) {
+    try {
+      ((Object) null).getClass();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+
     try {
       throw_(null);
       throw new RuntimeException();