Working dex2oat and oatexec

adb shell dex2oatd --dex-file=/system/framework/core.jar     --image=/system/framework/boot.oat --base=0x50000000 "'--method=Ljava/lang/System;logI(Ljava/lang/String;)V'" "'--method=Ljava/lang/System;log(CLjava/lang/String;Ljava/lang/Throwable;)V'"
adb shell dex2oatd --boot-dex-file=/system/framework/core.jar --boot=/system/framework/boot.oat --dex-file=/system/framework/art-test-dex-HelloWorld.jar --image=/system/framework/art-test-dex-HelloWorld.oat
adb shell oatexecd -Xbootclasspath:/system/framework/core.jar -Xbootimage:/system/framework/boot.oat -classpath /system/framework/art-test-dex-HelloWorld.jar -Ximage:/system/framework/art-test-dex-HelloWorld.oat HelloWorld

09-05 17:58:18.912  2385  2385 I System  : Hello, world!

Change-Id: I53e534068584f0c3a837313e4d517a0e4a7154fc
diff --git a/src/class_loader.cc b/src/class_loader.cc
index 9769136..8f8e829 100644
--- a/src/class_loader.cc
+++ b/src/class_loader.cc
@@ -18,6 +18,7 @@
 Class* PathClassLoader::dalvik_system_PathClassLoader_ = NULL;
 
 const PathClassLoader* PathClassLoader::Alloc(std::vector<const DexFile*> dex_files) {
+  DCHECK(dalvik_system_PathClassLoader_ != NULL);
   PathClassLoader* p = down_cast<PathClassLoader*>(dalvik_system_PathClassLoader_->AllocObject());
   p->SetClassPath(dex_files);
   return p;