Undo dex2dex compilation before invoking LoadHook

We need to undo any dex_to_dex compilation that might have taken place
before passing a dex file to any registered ClassFileLoadHooks to
ensure that no internal opcodes are present in any methods.

Test: ./test.py --host -j40
Bug: 36653594

Change-Id: Ia42c77312e685d69f6b3ea764fad01710b10ab45
diff --git a/runtime/openjdkjvmti/fixed_up_dex_file.cc b/runtime/openjdkjvmti/fixed_up_dex_file.cc
new file mode 100644
index 0000000..3338358
--- /dev/null
+++ b/runtime/openjdkjvmti/fixed_up_dex_file.cc
@@ -0,0 +1,145 @@
+/* Copyright (C) 2017 The Android Open Source Project
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This file implements interfaces from the file jvmti.h. This implementation
+ * is licensed under the same terms as the file jvmti.h.  The
+ * copyright and license information for the file jvmti.h follows.
+ *
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "fixed_up_dex_file.h"
+#include "dex_file-inl.h"
+
+// Compiler includes.
+#include "dex/dex_to_dex_decompiler.h"
+
+// Runtime includes.
+#include "oat_file.h"
+#include "vdex_file.h"
+
+namespace openjdkjvmti {
+
+static void RecomputeDexChecksum(art::DexFile* dex_file)
+    REQUIRES_SHARED(art::Locks::mutator_lock_) {
+  reinterpret_cast<art::DexFile::Header*>(const_cast<uint8_t*>(dex_file->Begin()))->checksum_ =
+      dex_file->CalculateChecksum();
+}
+
+// TODO This is more complicated then it seems like it should be.
+// The fact we don't keep around the data of where in the flat binary log of dex-quickening changes
+// each dex file starts means we need to search for it. Since JVMTI is the exception though we are
+// not going to put in the effort to optimize for it.
+static void DoDexUnquicken(const art::DexFile& new_dex_file,
+                           const art::DexFile& original_dex_file)
+    REQUIRES_SHARED(art::Locks::mutator_lock_) {
+  const art::OatDexFile* oat_dex = original_dex_file.GetOatDexFile();
+  if (oat_dex == nullptr) {
+    return;
+  }
+  const art::OatFile* oat_file = oat_dex->GetOatFile();
+  if (oat_file == nullptr) {
+    return;
+  }
+  const art::VdexFile* vdex = oat_file->GetVdexFile();
+  if (vdex == nullptr || vdex->GetQuickeningInfo().size() == 0) {
+    return;
+  }
+  const art::ArrayRef<const uint8_t> quickening_info(vdex->GetQuickeningInfo());
+  const uint8_t* quickening_info_ptr = quickening_info.data();
+  for (const art::OatDexFile* cur_oat_dex : oat_file->GetOatDexFiles()) {
+    std::string error;
+    std::unique_ptr<const art::DexFile> cur_dex_file(cur_oat_dex->OpenDexFile(&error));
+    DCHECK(cur_dex_file.get() != nullptr);
+    // Is this the dex file we are looking for?
+    if (UNLIKELY(cur_dex_file->Begin() == original_dex_file.Begin())) {
+      // Simple sanity check.
+      CHECK_EQ(new_dex_file.NumClassDefs(), original_dex_file.NumClassDefs());
+      for (uint32_t i = 0; i < new_dex_file.NumClassDefs(); ++i) {
+        const art::DexFile::ClassDef& class_def = new_dex_file.GetClassDef(i);
+        const uint8_t* class_data = new_dex_file.GetClassData(class_def);
+        if (class_data == nullptr) {
+          continue;
+        }
+        for (art::ClassDataItemIterator it(new_dex_file, class_data); it.HasNext(); it.Next()) {
+          if (it.IsAtMethod() && it.GetMethodCodeItem() != nullptr) {
+            uint32_t quickening_size = *reinterpret_cast<const uint32_t*>(quickening_info_ptr);
+            quickening_info_ptr += sizeof(uint32_t);
+            art::optimizer::ArtDecompileDEX(
+                *it.GetMethodCodeItem(),
+                art::ArrayRef<const uint8_t>(quickening_info_ptr, quickening_size),
+                /*decompile_return_instruction*/true);
+            quickening_info_ptr += quickening_size;
+          }
+        }
+      }
+      // We don't need to bother looking through the rest of the dex-files.
+      break;
+    } else {
+      // Not the dex file we want. Skip over all the quickening info for all its classes.
+      for (uint32_t i = 0; i < cur_dex_file->NumClassDefs(); ++i) {
+        const art::DexFile::ClassDef& class_def = cur_dex_file->GetClassDef(i);
+        const uint8_t* class_data = cur_dex_file->GetClassData(class_def);
+        if (class_data == nullptr) {
+          continue;
+        }
+        for (art::ClassDataItemIterator it(*cur_dex_file, class_data); it.HasNext(); it.Next()) {
+          if (it.IsAtMethod() && it.GetMethodCodeItem() != nullptr) {
+            uint32_t quickening_size = *reinterpret_cast<const uint32_t*>(quickening_info_ptr);
+            quickening_info_ptr += sizeof(uint32_t);
+            quickening_info_ptr += quickening_size;
+          }
+        }
+      }
+    }
+  }
+}
+
+std::unique_ptr<FixedUpDexFile> FixedUpDexFile::Create(const art::DexFile& original) {
+  // Copy the data into mutable memory.
+  std::vector<unsigned char> data;
+  data.resize(original.Size());
+  memcpy(data.data(), original.Begin(), original.Size());
+  std::string error;
+  std::unique_ptr<const art::DexFile> new_dex_file(art::DexFile::Open(
+      data.data(),
+      data.size(),
+      /*location*/"Unquickening_dexfile.dex",
+      /*location_checksum*/0,
+      /*oat_dex_file*/nullptr,
+      /*verify*/false,
+      /*verify_checksum*/false,
+      &error));
+  if (new_dex_file.get() == nullptr) {
+    LOG(ERROR) << "Unable to open dex file from memory for unquickening! error: " << error;
+    return nullptr;
+  }
+
+  DoDexUnquicken(*new_dex_file, original);
+  RecomputeDexChecksum(const_cast<art::DexFile*>(new_dex_file.get()));
+  std::unique_ptr<FixedUpDexFile> ret(new FixedUpDexFile(std::move(new_dex_file), std::move(data)));
+  return ret;
+}
+
+}  // namespace openjdkjvmti