diff --git a/src/class_linker.cc b/src/class_linker.cc
index 8638b30..589213a 100644
--- a/src/class_linker.cc
+++ b/src/class_linker.cc
@@ -550,6 +550,48 @@
   }
 }
 
+const OatFile* ClassLinker::GenerateOatFile(const std::string& filename) {
+  std::string oat_filename(GetArtCacheFilenameOrDie(OatFile::DexFilenameToOatFilename(filename)));
+
+  // fork and exec dex2oat
+  pid_t pid = fork();
+  if (pid == 0) {
+    std::string boot_image_option("--boot-image=");
+    boot_image_option += Heap::GetSpaces()[0]->GetImageFilename();
+
+    std::string dex_file_option("--dex-file=");
+    dex_file_option += filename;
+
+    std::string oat_file_option("--oat=");
+    oat_file_option += oat_filename;
+
+    execl("/system/bin/dex2oatd",
+          "/system/bin/dex2oatd",
+          "-Xms64m",
+          "-Xmx64m",
+          boot_image_option.c_str(),
+          dex_file_option.c_str(),
+          oat_file_option.c_str(),
+          NULL);
+
+    PLOG(FATAL) << "execl(dex2oatd) failed";
+    return NULL;
+  } else {
+    // wait for dex2oat to finish
+    int status;
+    pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
+    if (got_pid != pid) {
+      PLOG(ERROR) << "waitpid failed: wanted " << pid << ", got " << got_pid;
+      return NULL;
+    }
+    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+      LOG(ERROR) << "dex2oatd failed with dex-file=" << filename;
+      return NULL;
+    }
+  }
+  return OatFile::Open(oat_filename, "", NULL);
+}
+
 OatFile* ClassLinker::OpenOat(const Space* space) {
   MutexLock mu(dex_lock_);
   const Runtime* runtime = Runtime::Current();
@@ -584,7 +626,18 @@
 const OatFile* ClassLinker::FindOatFile(const DexFile& dex_file) {
   MutexLock mu(dex_lock_);
   // TODO: check if dex_file matches an OatDexFile location and checksum
-  return FindOatFile(OatFile::DexFileToOatFilename(dex_file));
+  const OatFile* oat_file = FindOatFile(OatFile::DexFilenameToOatFilename(dex_file.GetLocation()));
+  if (oat_file != NULL) {
+    return oat_file;
+  }
+  // generate oat file if it wasn't found
+  oat_file = GenerateOatFile(dex_file.GetLocation());
+  if (oat_file == NULL) {
+    LOG(ERROR) << "Failed to generate oat file from dex file " << dex_file.GetLocation();
+    return NULL;
+  }
+  oat_files_.push_back(oat_file);
+  return oat_file;
 }
 
 const OatFile* ClassLinker::FindOpenedOatFile(const std::string& location) {
@@ -612,14 +665,14 @@
     }
 
     // not found in /foo/bar/baz.oat? try /data/art-cache/foo@bar@baz.oat
-    std::string cache_location = GetArtCacheOatFilenameOrDie(location);
+    std::string cache_location = GetArtCacheFilenameOrDie(location);
     oat_file = FindOpenedOatFile(cache_location);
     if (oat_file != NULL) {
       return oat_file;
     }
     oat_file = OatFile::Open(cache_location, "", NULL);
     if (oat_file  == NULL) {
-      LOG(ERROR) << "Failed to open oat file from " << location << " or " << cache_location << ".";
+      LOG(INFO) << "Failed to open oat file from " << location << " or " << cache_location << ".";
       return NULL;
     }
   }
diff --git a/src/class_linker.h b/src/class_linker.h
index 12d7b37..dd78174 100644
--- a/src/class_linker.h
+++ b/src/class_linker.h
@@ -209,6 +209,9 @@
   DexCache* FindDexCache(const DexFile& dex_file) const;
   bool IsDexFileRegistered(const DexFile& dex_file) const;
 
+  // Generate an oat file from a dex file
+  const OatFile* GenerateOatFile(const std::string& filename);
+
   // Find, possibily opening, an OatFile corresponding to a DexFile
   const OatFile* FindOatFile(const DexFile& dex_file);
   const OatFile* FindOatFile(const std::string& location);
diff --git a/src/dalvik_system_DexFile.cc b/src/dalvik_system_DexFile.cc
index 6e0a923..40a1626 100644
--- a/src/dalvik_system_DexFile.cc
+++ b/src/dalvik_system_DexFile.cc
@@ -19,11 +19,9 @@
 #include "class_loader.h"
 #include "class_linker.h"
 #include "dex_file.h"
-#include "file.h"
 #include "logging.h"
 #include "os.h"
 #include "runtime.h"
-#include "space.h"
 #include "zip_archive.h"
 #include "toStringArray.h"
 #include "ScopedUtfChars.h"
@@ -91,79 +89,43 @@
   if (env->ExceptionCheck()) {
     return 0;
   }
-  if (outputName.c_str() != NULL) {
-    // Check that output name ends in .dex.
-    if (!StringPiece(outputName.c_str()).ends_with(".dex")) {
-      LOG(ERROR) << "Output filename '" << outputName.c_str() << "' does not end with .dex";
-      return 0;
-    }
-
-    // Extract the dex file.
-    UniquePtr<ZipArchive> zip_archive(ZipArchive::Open(sourceName.c_str()));
-    if (zip_archive.get() == NULL) {
-      LOG(ERROR) << "Failed to open " << sourceName.c_str() << " when looking for classes.dex";
-      return 0;
-    }
-
-    UniquePtr<ZipEntry> zip_entry(zip_archive->Find(DexFile::kClassesDex));
-    if (zip_entry.get() == NULL) {
-      LOG(ERROR) << "Failed to find classes.dex within " << sourceName.c_str();
-      return 0;
-    }
-
-    UniquePtr<File> file(OS::OpenFile(outputName.c_str(), true));
-    bool success = zip_entry->Extract(*file);
-    if (!success) {
-      LOG(ERROR) << "Failed to extract classes.dex from " << sourceName.c_str();
-      return 0;
-    }
-
-    // Fork and exec dex2oat.
-    pid_t pid = fork();
-    if (pid == 0) {
-      std::string boot_image_option("--boot-image=");
-      boot_image_option += Heap::GetSpaces()[0]->GetImageFilename();
-
-      std::string dex_file_option("--dex-file=");
-      dex_file_option += outputName.c_str();
-
-      std::string oat_file_option("--oat=");
-      oat_file_option += outputName.c_str();
-      oat_file_option.erase(oat_file_option.size() - 3);
-      oat_file_option += "oat";
-
-      execl("/system/bin/dex2oatd",
-            "/system/bin/dex2oatd",
-            "-Xms64m",
-            "-Xmx64m",
-            boot_image_option.c_str(),
-            dex_file_option.c_str(),
-            oat_file_option.c_str(),
-            NULL);
-
-      PLOG(FATAL) << "execl(dex2oatd) failed";
-      return 0;
-    } else {
-      // Wait for dex2oat to finish.
-      int status;
-      pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
-      if (got_pid != pid) {
-        PLOG(ERROR) << "waitpid failed: wanted " << pid << ", got " << got_pid;
-        return 0;
-      }
-      if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-        LOG(ERROR) << "dex2oatd failed with dex-file=" << outputName.c_str();
-        return 0;
-      }
-    }
-  }
-
   const DexFile* dex_file;
   if (outputName.c_str() == NULL) {
     dex_file = DexFile::Open(sourceName.c_str(), "");
   } else {
+    // Sanity check the arguments.
+    if (!IsValidZipFilename(sourceName.c_str()) || !IsValidDexFilename(outputName.c_str())) {
+      LOG(ERROR) << "Bad filenames extracting dex '" << outputName.c_str()
+                 << "' from zip '" << sourceName.c_str() << "'";
+      return NULL;
+    }
+
+    // Extract classes.dex from the input zip file to the output dex file
+    UniquePtr<ZipArchive> zip_archive(ZipArchive::Open(sourceName.c_str()));
+    if (zip_archive.get() == NULL) {
+      LOG(ERROR) << "Failed to open " << sourceName.c_str() << " when looking for classes.dex";
+      return NULL;
+    }
+    UniquePtr<ZipEntry> zip_entry(zip_archive->Find(DexFile::kClassesDex));
+    if (zip_entry.get() == NULL) {
+      LOG(ERROR) << "Failed to find classes.dex within " << sourceName.c_str();
+      return NULL;
+    }
+    UniquePtr<File> file(OS::OpenFile(outputName.c_str(), true));
+    bool success = zip_entry->Extract(*file);
+    if (!success) {
+      LOG(ERROR) << "Failed to extract classes.dex from " << sourceName.c_str();
+      return NULL;
+    }
     dex_file = DexFile::Open(outputName.c_str(), "");
+
+    // Generate the oat file for the newly extracted dex file
+    ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+    if (class_linker->GenerateOatFile(outputName.c_str()) == NULL) {
+      return 0;
+    }
   }
+
   if (dex_file == NULL) {
     jniThrowExceptionFmt(env, "java/io/IOException", "unable to open DEX file: %s",
                          sourceName.c_str());
diff --git a/src/dex_file.cc b/src/dex_file.cc
index 83866a9..7a41845 100644
--- a/src/dex_file.cc
+++ b/src/dex_file.cc
@@ -57,13 +57,12 @@
 
 const DexFile* DexFile::Open(const std::string& filename,
                              const std::string& strip_location_prefix) {
-  if (filename.size() < 4) {
-    LOG(WARNING) << "Attempting to open dex file with unknown extension '" << filename << "'";
-  }
-  std::string suffix(filename.substr(filename.size() - 4));
-  if (suffix == ".zip" || suffix == ".jar" || suffix == ".apk") {
+  if (IsValidZipFilename(filename)) {
     return DexFile::OpenZip(filename, strip_location_prefix);
   } else {
+    if (!IsValidDexFilename(filename)) {
+      LOG(WARNING) << "Attempting to open dex file with unknown extension '" << filename << "'";
+    }
     return DexFile::OpenFile(filename, filename, strip_location_prefix);
   }
 }
@@ -200,14 +199,9 @@
                  << " when looking for classes.dex";
       return NULL;
   }
-  std::string cache_file(absolute_path+1); // skip leading slash
-  std::replace(cache_file.begin(), cache_file.end(), '/', '@');
-  cache_file.push_back('@');
-  cache_file.append(kClassesDex);
-  // Example cache_file = parent@dir@foo.jar@classes.dex
-
-  std::string art_cache = GetArtCacheOrDie();
-  std::string cache_path_tmp = art_cache + "/" + cache_file;
+  std::string cache_path_tmp(GetArtCacheFilenameOrDie(absolute_path));
+  cache_path_tmp.push_back('@');
+  cache_path_tmp.append(kClassesDex);
   // Example cache_path_tmp = /data/art-cache/parent@dir@foo.jar@classes.dex
 
   UniquePtr<ZipArchive> zip_archive(ZipArchive::Open(filename));
diff --git a/src/dex_file.h b/src/dex_file.h
index 070901b..3077ae6 100644
--- a/src/dex_file.h
+++ b/src/dex_file.h
@@ -330,6 +330,7 @@
   // Opens .dex file, guessing the container format based on file extension
   static const DexFile* Open(const std::string& filename,
                              const std::string& strip_location_prefix);
+
   // Closes a .dex file.
   virtual ~DexFile();
 
diff --git a/src/oat_file.cc b/src/oat_file.cc
index 6e8c60f..3dcde8e 100644
--- a/src/oat_file.cc
+++ b/src/oat_file.cc
@@ -10,15 +10,12 @@
 
 namespace art {
 
-std::string OatFile::DexFileToOatFilename(const DexFile& dex_file) {
-  std::string location(dex_file.GetLocation());
-  CHECK(StringPiece(location).ends_with(".dex")
-        || StringPiece(location).ends_with(".zip")
-        || StringPiece(location).ends_with(".jar")
-        || StringPiece(location).ends_with(".apk"));
-  location.erase(location.size()-3);
-  location += "oat";
-  return location;
+std::string OatFile::DexFilenameToOatFilename(const std::string& location) {
+  LOG(INFO) << "dexfilenametooatfilename " << location;
+  CHECK(IsValidDexFilename(location) || IsValidZipFilename(location));
+  std::string oat_location = location.substr(0, location.size()-3);
+  oat_location += "oat";
+  return oat_location;
 }
 
 OatFile* OatFile::Open(const std::string& filename,
diff --git a/src/oat_file.h b/src/oat_file.h
index e83b294..1ee8c91 100644
--- a/src/oat_file.h
+++ b/src/oat_file.h
@@ -17,7 +17,7 @@
  public:
 
   // Returns an OatFile name based on a DexFile location
-  static std::string DexFileToOatFilename(const DexFile& dex_file);
+  static std::string DexFilenameToOatFilename(const std::string& location);
 
   // Open an oat file. Returns NULL on failure.  Requested base can
   // optionally be used to request where the file should be loaded.
diff --git a/src/oatopt.cc b/src/oatopt.cc
index b2a33cb..133af59 100644
--- a/src/oatopt.cc
+++ b/src/oatopt.cc
@@ -47,7 +47,7 @@
   dex_file_option += zip_name;
 
   std::string oat_file_option("--oat=");
-  oat_file_option += GetArtCacheOatFilenameOrDie(OatFile::DexFileToOatFilename(*dex_file.get()));
+  oat_file_option += GetArtCacheFilenameOrDie(OatFile::DexFilenameToOatFilename(dex_file.get()->GetLocation()));
 
   execl("/system/bin/dex2oatd",
         "/system/bin/dex2oatd",
diff --git a/src/utils.cc b/src/utils.cc
index ceaf7cd..bfd7e79 100644
--- a/src/utils.cc
+++ b/src/utils.cc
@@ -514,7 +514,7 @@
   return art_cache;
 }
 
-std::string GetArtCacheOatFilenameOrDie(const std::string& location) {
+std::string GetArtCacheFilenameOrDie(const std::string& location) {
   std::string art_cache = GetArtCacheOrDie();
   CHECK_EQ(location[0], '/');
   std::string cache_file(location, 1); // skip leading slash
@@ -522,6 +522,22 @@
   return art_cache + "/" + cache_file;
 }
 
+bool IsValidZipFilename(const std::string& filename) {
+  if (filename.size() < 4) {
+    return false;
+  }
+  std::string suffix(filename.substr(filename.size() - 4));
+  return (suffix == ".zip" || suffix == ".jar" || suffix == ".apk");
+}
+
+bool IsValidDexFilename(const std::string& filename) {
+  if (filename.size() < 4) {
+    return false;
+  }
+  std::string suffix(filename.substr(filename.size() - 4));
+  return (suffix == ".dex");
+}
+
 }  // namespace art
 
 // Neither bionic nor glibc exposes gettid(2).
diff --git a/src/utils.h b/src/utils.h
index dd597e9..df1e1c1 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -221,8 +221,12 @@
 // Returns the art-cache location, or dies trying.
 std::string GetArtCacheOrDie();
 
-// Returns the art-cache location for an OatFile, or dies trying.
-std::string GetArtCacheOatFilenameOrDie(const std::string& location);
+// Returns the art-cache location for a DexFile or OatFile, or dies trying.
+std::string GetArtCacheFilenameOrDie(const std::string& location);
+
+// Check whether the given filename has a valid zip or dex extension
+bool IsValidZipFilename(const std::string& filename);
+bool IsValidDexFilename(const std::string& filename);
 
 }  // namespace art
 
diff --git a/test/etc/default-build b/test/etc/default-build
index 9647794..e71db2a 100755
--- a/test/etc/default-build
+++ b/test/etc/default-build
@@ -28,12 +28,6 @@
     --dump-width=1000 classes
 zip ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.jar classes.dex
 
-dex2oatd -Xms16m -Xmx16m \
-    --boot-image=${ANDROID_PRODUCT_OUT}/data/art-test/core.art \
-    --dex-file=${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.jar \
-    --oat=${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.oat \
-    --host-prefix=${ANDROID_PRODUCT_OUT}
-
 if [ -r src-ex ]; then
     mkdir classes-ex
     ${JAVAC} -d classes-ex -cp classes `find src-ex -name '*.java'`
diff --git a/test/etc/push-and-run-test-jar b/test/etc/push-and-run-test-jar
index ec7bf46..ae1474a 100755
--- a/test/etc/push-and-run-test-jar
+++ b/test/etc/push-and-run-test-jar
@@ -91,13 +91,9 @@
 
 if [ "$QUIET" = "n" ]; then
   adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.jar /system/framework
-  adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.oat /data/art-test
-  adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.art /data/art-test
   adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME-ex.jar /data/art-test
 else
   adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.jar /data/art-test >/dev/null 2>&1
-  adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.oat /data/art-test >/dev/null 2>&1
-  adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME.art /data/art-test >/dev/null 2>&1
   adb push ${ANDROID_PRODUCT_OUT}/data/art-test/$TEST_NAME-ex.jar /data/art-test >/dev/null 2>&1
 fi