Move transaction creation to runtime

Move the transaction creation to runtime instead of passing a pointer to
runtime when EnterTransactionMode. Because later there will be more
places to create transaction so this makes the code cleaner and more
compact.

Test: make test-art-host -j64
Change-Id: I971edf3110eb6634b6e0f7f56256be04517a5281
diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index cf04e41..7970b4c 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -2331,10 +2331,8 @@
             // a ReaderWriterMutex but we're holding the mutator lock so we fail mutex sanity
             // checks in Thread::AssertThreadSuspensionIsAllowable.
             Runtime* const runtime = Runtime::Current();
-            Transaction transaction;
-
             // Run the class initializer in transaction mode.
-            runtime->EnterTransactionMode(&transaction);
+            runtime->EnterTransactionMode();
             bool success = manager_->GetClassLinker()->EnsureInitialized(soa.Self(), klass, true,
                                                                          true);
             // TODO we detach transaction from runtime to indicate we quit the transactional
@@ -2343,7 +2341,11 @@
 
             {
               ScopedAssertNoThreadSuspension ants("Transaction end");
-              runtime->ExitTransactionMode();
+
+              if (success) {
+                runtime->ExitTransactionMode();
+                DCHECK(!runtime->IsActiveTransaction());
+              }
 
               if (!success) {
                 CHECK(soa.Self()->IsExceptionPending());
@@ -2357,7 +2359,7 @@
                   *file_log << exception->Dump() << "\n";
                 }
                 soa.Self()->ClearException();
-                transaction.Rollback();
+                runtime->RollbackAndExitTransactionMode();
                 CHECK_EQ(old_status, klass->GetStatus()) << "Previous class status not restored";
               } else if (is_boot_image) {
                 // For boot image, we want to put the updated status in the oat class since we can't
diff --git a/runtime/interpreter/unstarted_runtime_test.cc b/runtime/interpreter/unstarted_runtime_test.cc
index 3461a65..87fa8be 100644
--- a/runtime/interpreter/unstarted_runtime_test.cc
+++ b/runtime/interpreter/unstarted_runtime_test.cc
@@ -780,44 +780,40 @@
     {
       JValue result;
       tmp->SetVReg(0, static_cast<int32_t>(i));
-      Transaction transaction;
-      Runtime::Current()->EnterTransactionMode(&transaction);
+      Runtime::Current()->EnterTransactionMode();
       UnstartedCharacterToLowerCase(self, tmp, &result, 0);
+      ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
       Runtime::Current()->ExitTransactionMode();
       ASSERT_TRUE(self->IsExceptionPending());
-      ASSERT_TRUE(transaction.IsAborted());
     }
     {
       JValue result;
       tmp->SetVReg(0, static_cast<int32_t>(i));
-      Transaction transaction;
-      Runtime::Current()->EnterTransactionMode(&transaction);
+      Runtime::Current()->EnterTransactionMode();
       UnstartedCharacterToUpperCase(self, tmp, &result, 0);
+      ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
       Runtime::Current()->ExitTransactionMode();
       ASSERT_TRUE(self->IsExceptionPending());
-      ASSERT_TRUE(transaction.IsAborted());
     }
   }
   for (uint64_t i = 256; i <= std::numeric_limits<uint32_t>::max(); i <<= 1) {
     {
       JValue result;
       tmp->SetVReg(0, static_cast<int32_t>(i));
-      Transaction transaction;
-      Runtime::Current()->EnterTransactionMode(&transaction);
+      Runtime::Current()->EnterTransactionMode();
       UnstartedCharacterToLowerCase(self, tmp, &result, 0);
+      ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
       Runtime::Current()->ExitTransactionMode();
       ASSERT_TRUE(self->IsExceptionPending());
-      ASSERT_TRUE(transaction.IsAborted());
     }
     {
       JValue result;
       tmp->SetVReg(0, static_cast<int32_t>(i));
-      Transaction transaction;
-      Runtime::Current()->EnterTransactionMode(&transaction);
+      Runtime::Current()->EnterTransactionMode();
       UnstartedCharacterToUpperCase(self, tmp, &result, 0);
+      ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
       Runtime::Current()->ExitTransactionMode();
       ASSERT_TRUE(self->IsExceptionPending());
-      ASSERT_TRUE(transaction.IsAborted());
     }
   }
 
@@ -996,12 +992,11 @@
     ShadowFrame* caller_frame = ShadowFrame::CreateDeoptimizedFrame(10, nullptr, caller_method, 0);
     shadow_frame->SetLink(caller_frame);
 
-    Transaction transaction;
-    Runtime::Current()->EnterTransactionMode(&transaction);
+    Runtime::Current()->EnterTransactionMode();
     UnstartedThreadLocalGet(self, shadow_frame, &result, 0);
+    ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
     Runtime::Current()->ExitTransactionMode();
     ASSERT_TRUE(self->IsExceptionPending());
-    ASSERT_TRUE(transaction.IsAborted());
     self->ClearException();
 
     ShadowFrame::DeleteDeoptimizedFrame(caller_frame);
@@ -1066,12 +1061,11 @@
   PrepareForAborts();
 
   {
-    Transaction transaction;
-    Runtime::Current()->EnterTransactionMode(&transaction);
+    Runtime::Current()->EnterTransactionMode();
     UnstartedThreadCurrentThread(self, shadow_frame, &result, 0);
+    ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
     Runtime::Current()->ExitTransactionMode();
     ASSERT_TRUE(self->IsExceptionPending());
-    ASSERT_TRUE(transaction.IsAborted());
     self->ClearException();
   }
 
@@ -1138,28 +1132,27 @@
       mirror::String* name_string = mirror::String::AllocFromModifiedUtf8(self, name);
       CHECK(name_string != nullptr);
 
-      Transaction transaction;
       if (in_transaction) {
-        Runtime::Current()->EnterTransactionMode(&transaction);
+        Runtime::Current()->EnterTransactionMode();
       }
       CHECK(!self->IsExceptionPending());
 
       runner(self, shadow_frame, name_string, &result);
 
-      if (in_transaction) {
-        Runtime::Current()->ExitTransactionMode();
-      }
-
       if (should_succeed) {
         CHECK(!self->IsExceptionPending()) << name << " " << self->GetException()->Dump();
         CHECK(result.GetL() != nullptr) << name;
       } else {
         CHECK(self->IsExceptionPending()) << name;
         if (in_transaction) {
-          ASSERT_TRUE(transaction.IsAborted());
+          ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
         }
         self->ClearException();
       }
+
+      if (in_transaction) {
+        Runtime::Current()->ExitTransactionMode();
+      }
     }
 
     ShadowFrame::DeleteDeoptimizedFrame(shadow_frame);
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index ebee5ea..01b87b9 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -2065,19 +2065,25 @@
 }
 
 // Transaction support.
-void Runtime::EnterTransactionMode(Transaction* transaction) {
+void Runtime::EnterTransactionMode() {
   DCHECK(IsAotCompiler());
-  DCHECK(transaction != nullptr);
   DCHECK(!IsActiveTransaction());
-  preinitialization_transaction_ = transaction;
+  preinitialization_transaction_ = std::make_unique<Transaction>();
 }
 
 void Runtime::ExitTransactionMode() {
   DCHECK(IsAotCompiler());
-  DCHECK(IsActiveTransaction());
   preinitialization_transaction_ = nullptr;
 }
 
+void Runtime::RollbackAndExitTransactionMode() {
+  DCHECK(IsAotCompiler());
+  DCHECK(IsActiveTransaction());
+  std::unique_ptr<Transaction> rollback_transaction_= std::move(preinitialization_transaction_);
+  ExitTransactionMode();
+  rollback_transaction_->Rollback();
+}
+
 bool Runtime::IsTransactionAborted() const {
   if (!IsActiveTransaction()) {
     return false;
diff --git a/runtime/runtime.h b/runtime/runtime.h
index af9d215..0200dc0 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -24,6 +24,7 @@
 #include <set>
 #include <string>
 #include <utility>
+#include <memory>
 #include <vector>
 
 #include "arch/instruction_set.h"
@@ -457,8 +458,11 @@
   bool IsActiveTransaction() const {
     return preinitialization_transaction_ != nullptr;
   }
-  void EnterTransactionMode(Transaction* transaction);
+  void EnterTransactionMode();
   void ExitTransactionMode();
+  // Transaction rollback and exit transaction are always done together, it's convenience to
+  // do them in one function.
+  void RollbackAndExitTransactionMode() REQUIRES_SHARED(Locks::mutator_lock_);
   bool IsTransactionAborted() const;
 
   void AbortTransactionAndThrowAbortError(Thread* self, const std::string& abort_message)
@@ -842,7 +846,7 @@
   bool dump_gc_performance_on_shutdown_;
 
   // Transaction used for pre-initializing classes at compilation time.
-  Transaction* preinitialization_transaction_;
+  std::unique_ptr<Transaction> preinitialization_transaction_;
 
   // If kNone, verification is disabled. kEnable by default.
   verifier::VerifyMode verify_;
diff --git a/runtime/transaction_test.cc b/runtime/transaction_test.cc
index 9206292..e52dd08 100644
--- a/runtime/transaction_test.cc
+++ b/runtime/transaction_test.cc
@@ -69,14 +69,12 @@
     mirror::Class::Status old_status = h_klass->GetStatus();
     LockWord old_lock_word = h_klass->GetLockWord(false);
 
-    Transaction transaction;
-    Runtime::Current()->EnterTransactionMode(&transaction);
+    Runtime::Current()->EnterTransactionMode();
     bool success = class_linker_->EnsureInitialized(soa.Self(), h_klass, true, true);
-    Runtime::Current()->ExitTransactionMode();
+    ASSERT_TRUE(Runtime::Current()->IsTransactionAborted());
     ASSERT_FALSE(success);
     ASSERT_TRUE(h_klass->IsErroneous());
     ASSERT_TRUE(soa.Self()->IsExceptionPending());
-    ASSERT_TRUE(transaction.IsAborted());
 
     // Check class's monitor get back to its original state without rolling back changes.
     LockWord new_lock_word = h_klass->GetLockWord(false);
@@ -84,7 +82,7 @@
 
     // Check class status is rolled back properly.
     soa.Self()->ClearException();
-    transaction.Rollback();
+    Runtime::Current()->RollbackAndExitTransactionMode();
     ASSERT_EQ(old_status, h_klass->GetStatus());
   }
 };
@@ -97,15 +95,12 @@
       hs.NewHandle(class_linker_->FindSystemClass(soa.Self(), "Ljava/lang/Object;")));
   ASSERT_TRUE(h_klass != nullptr);
 
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   Handle<mirror::Object> h_obj(hs.NewHandle(h_klass->AllocObject(soa.Self())));
   ASSERT_TRUE(h_obj != nullptr);
   ASSERT_EQ(h_obj->GetClass(), h_klass.Get());
-  Runtime::Current()->ExitTransactionMode();
-
   // Rolling back transaction's changes must not clear the Object::class field.
-  transaction.Rollback();
+  Runtime::Current()->RollbackAndExitTransactionMode();
   EXPECT_EQ(h_obj->GetClass(), h_klass.Get());
 }
 
@@ -124,15 +119,13 @@
   h_obj->MonitorEnter(soa.Self());
   LockWord old_lock_word = h_obj->GetLockWord(false);
 
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   // Unlock object's monitor inside the transaction.
   h_obj->MonitorExit(soa.Self());
   LockWord new_lock_word = h_obj->GetLockWord(false);
-  Runtime::Current()->ExitTransactionMode();
-
   // Rolling back transaction's changes must not change monitor's state.
-  transaction.Rollback();
+  Runtime::Current()->RollbackAndExitTransactionMode();
+
   LockWord aborted_lock_word = h_obj->GetLockWord(false);
   EXPECT_FALSE(LockWord::Equal<false>(old_lock_word, new_lock_word));
   EXPECT_TRUE(LockWord::Equal<false>(aborted_lock_word, new_lock_word));
@@ -148,8 +141,7 @@
 
   constexpr int32_t kArraySize = 2;
 
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
 
   // Allocate an array during transaction.
   Handle<mirror::Array> h_obj(
@@ -159,10 +151,9 @@
                                      Runtime::Current()->GetHeap()->GetCurrentAllocator())));
   ASSERT_TRUE(h_obj != nullptr);
   ASSERT_EQ(h_obj->GetClass(), h_klass.Get());
-  Runtime::Current()->ExitTransactionMode();
+  Runtime::Current()->RollbackAndExitTransactionMode();
 
   // Rolling back transaction's changes must not reset array's length.
-  transaction.Rollback();
   EXPECT_EQ(h_obj->GetLength(), kArraySize);
 }
 
@@ -238,8 +229,7 @@
   ASSERT_EQ(h_obj->GetClass(), h_klass.Get());
 
   // Modify fields inside transaction then rollback changes.
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   booleanField->SetBoolean<true>(h_klass.Get(), true);
   byteField->SetByte<true>(h_klass.Get(), 1);
   charField->SetChar<true>(h_klass.Get(), 1u);
@@ -249,8 +239,7 @@
   floatField->SetFloat<true>(h_klass.Get(), 1.0);
   doubleField->SetDouble<true>(h_klass.Get(), 1.0);
   objectField->SetObject<true>(h_klass.Get(), h_obj.Get());
-  Runtime::Current()->ExitTransactionMode();
-  transaction.Rollback();
+  Runtime::Current()->RollbackAndExitTransactionMode();
 
   // Check values have properly been restored to their original (default) value.
   EXPECT_EQ(booleanField->GetBoolean(h_klass.Get()), false);
@@ -340,8 +329,7 @@
   ASSERT_EQ(h_obj->GetClass(), h_klass.Get());
 
   // Modify fields inside transaction then rollback changes.
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   booleanField->SetBoolean<true>(h_instance.Get(), true);
   byteField->SetByte<true>(h_instance.Get(), 1);
   charField->SetChar<true>(h_instance.Get(), 1u);
@@ -351,8 +339,7 @@
   floatField->SetFloat<true>(h_instance.Get(), 1.0);
   doubleField->SetDouble<true>(h_instance.Get(), 1.0);
   objectField->SetObject<true>(h_instance.Get(), h_obj.Get());
-  Runtime::Current()->ExitTransactionMode();
-  transaction.Rollback();
+  Runtime::Current()->RollbackAndExitTransactionMode();
 
   // Check values have properly been restored to their original (default) value.
   EXPECT_EQ(booleanField->GetBoolean(h_instance.Get()), false);
@@ -457,8 +444,7 @@
   ASSERT_EQ(h_obj->GetClass(), h_klass.Get());
 
   // Modify fields inside transaction then rollback changes.
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   booleanArray->SetWithoutChecks<true>(0, true);
   byteArray->SetWithoutChecks<true>(0, 1);
   charArray->SetWithoutChecks<true>(0, 1u);
@@ -468,8 +454,7 @@
   floatArray->SetWithoutChecks<true>(0, 1.0);
   doubleArray->SetWithoutChecks<true>(0, 1.0);
   objectArray->SetWithoutChecks<true>(0, h_obj.Get());
-  Runtime::Current()->ExitTransactionMode();
-  transaction.Rollback();
+  Runtime::Current()->RollbackAndExitTransactionMode();
 
   // Check values have properly been restored to their original (default) value.
   EXPECT_EQ(booleanArray->GetWithoutChecks(0), false);
@@ -511,8 +496,7 @@
   EXPECT_TRUE(class_linker_->LookupString(*dex_file, string_idx, h_dex_cache.Get()) == nullptr);
   EXPECT_TRUE(h_dex_cache->GetResolvedString(string_idx) == nullptr);
   // Do the transaction, then roll back.
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   bool success = class_linker_->EnsureInitialized(soa.Self(), h_klass, true, true);
   ASSERT_TRUE(success);
   ASSERT_TRUE(h_klass->IsInitialized());
@@ -523,8 +507,7 @@
     EXPECT_STREQ(s->ToModifiedUtf8().c_str(), kResolvedString);
     EXPECT_EQ(s, h_dex_cache->GetResolvedString(string_idx));
   }
-  Runtime::Current()->ExitTransactionMode();
-  transaction.Rollback();
+  Runtime::Current()->RollbackAndExitTransactionMode();
   // Check that the string did not stay resolved.
   EXPECT_TRUE(class_linker_->LookupString(*dex_file, string_idx, h_dex_cache.Get()) == nullptr);
   EXPECT_TRUE(h_dex_cache->GetResolvedString(string_idx) == nullptr);
@@ -547,8 +530,7 @@
   class_linker_->VerifyClass(soa.Self(), h_klass);
   ASSERT_TRUE(h_klass->IsVerified());
 
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   bool success = class_linker_->EnsureInitialized(soa.Self(), h_klass, true, true);
   Runtime::Current()->ExitTransactionMode();
   ASSERT_TRUE(success);
@@ -571,8 +553,7 @@
   class_linker_->VerifyClass(soa.Self(), h_klass);
   ASSERT_TRUE(h_klass->IsVerified());
 
-  Transaction transaction;
-  Runtime::Current()->EnterTransactionMode(&transaction);
+  Runtime::Current()->EnterTransactionMode();
   bool success = class_linker_->EnsureInitialized(soa.Self(), h_klass, true, true);
   Runtime::Current()->ExitTransactionMode();
   ASSERT_TRUE(success);