Introduce support for hardware simulators, starting with ARM64

Simulator support for ARM64 is implemented with VIXL.
Now codegen_test will also run on all supported hardware simulators.

Change-Id: Idc740f566175d1a23c373ea9292b8fc5ba526d00
diff --git a/runtime/simulator/code_simulator.cc b/runtime/simulator/code_simulator.cc
new file mode 100644
index 0000000..5023e48
--- /dev/null
+++ b/runtime/simulator/code_simulator.cc
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "simulator/code_simulator.h"
+#include "simulator/code_simulator_arm64.h"
+
+namespace art {
+
+CodeSimulator* CodeSimulator::CreateCodeSimulator(InstructionSet target_isa) {
+  DCHECK(CanSimulate(target_isa));
+  switch (target_isa) {
+    case kArm64:
+      return new arm64::CodeSimulatorArm64();
+    default:
+      UNREACHABLE();
+  }
+}
+
+bool CodeSimulator::CanSimulate(InstructionSet target_isa) {
+  switch (target_isa) {
+    case kArm64:
+      return arm64::CodeSimulatorArm64::CanSimulateArm64();
+    default:
+      // No simulator support for target.
+      return false;
+  }
+}
+
+}  // namespace art
diff --git a/runtime/simulator/code_simulator.h b/runtime/simulator/code_simulator.h
new file mode 100644
index 0000000..fe24c95
--- /dev/null
+++ b/runtime/simulator/code_simulator.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_SIMULATOR_CODE_SIMULATOR_H_
+#define ART_RUNTIME_SIMULATOR_CODE_SIMULATOR_H_
+
+#include "arch/instruction_set.h"
+
+namespace art {
+
+class CodeSimulator {
+ public:
+  virtual ~CodeSimulator() {}
+  static CodeSimulator* CreateCodeSimulator(InstructionSet target_isa);
+  static bool CanSimulate(InstructionSet target_isa);
+
+  virtual void RunFrom(intptr_t code_buffer) = 0;
+
+  // Get return value according to C ABI.
+  virtual bool GetCReturnBool() = 0;
+  virtual int32_t GetCReturnInt32() = 0;
+  virtual int64_t GetCReturnInt64() = 0;
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_SIMULATOR_CODE_SIMULATOR_H_
diff --git a/runtime/simulator/code_simulator_arm64.cc b/runtime/simulator/code_simulator_arm64.cc
new file mode 100644
index 0000000..3472e80
--- /dev/null
+++ b/runtime/simulator/code_simulator_arm64.cc
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "simulator/code_simulator_arm64.h"
+
+namespace art {
+namespace arm64 {
+
+// VIXL has not been tested on 32bit arches, so vixl::Simulator is not always
+// available. To avoid linker error on these arches, an early return is added in
+// each of the following methods, when vixl::Simulator is not available.
+// TODO: when vixl::Simulator is always available, remove the early returns.
+
+CodeSimulatorArm64::CodeSimulatorArm64()
+    : decoder_(nullptr), simulator_(nullptr) {
+  DCHECK(kCanSimulate);
+  if (!kCanSimulate) {
+    return;
+  }
+  decoder_ = new vixl::Decoder();
+  simulator_ = new vixl::Simulator(decoder_);
+}
+
+CodeSimulatorArm64::~CodeSimulatorArm64() {
+  if (!kCanSimulate) {
+    return;
+  }
+  delete simulator_;
+  delete decoder_;
+}
+
+void CodeSimulatorArm64::RunFrom(intptr_t code_buffer) {
+  if (!kCanSimulate) {
+    return;
+  }
+  simulator_->RunFrom(reinterpret_cast<const vixl::Instruction*>(code_buffer));
+}
+
+bool CodeSimulatorArm64::GetCReturnBool() {
+  DCHECK(kCanSimulate);
+  return simulator_->wreg(0);
+}
+
+int32_t CodeSimulatorArm64::GetCReturnInt32() {
+  DCHECK(kCanSimulate);
+  return simulator_->wreg(0);
+}
+
+int64_t CodeSimulatorArm64::GetCReturnInt64() {
+  DCHECK(kCanSimulate);
+  return simulator_->xreg(0);
+}
+
+}  // namespace arm64
+}  // namespace art
diff --git a/runtime/simulator/code_simulator_arm64.h b/runtime/simulator/code_simulator_arm64.h
new file mode 100644
index 0000000..5898fda
--- /dev/null
+++ b/runtime/simulator/code_simulator_arm64.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_SIMULATOR_CODE_SIMULATOR_ARM64_H_
+#define ART_RUNTIME_SIMULATOR_CODE_SIMULATOR_ARM64_H_
+
+#include "memory"
+#include "simulator/code_simulator.h"
+// TODO: make vixl clean wrt -Wshadow.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunknown-pragmas"
+#pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wmissing-noreturn"
+#include "vixl/a64/simulator-a64.h"
+#pragma GCC diagnostic pop
+
+namespace art {
+namespace arm64 {
+
+class CodeSimulatorArm64 : public CodeSimulator {
+ public:
+  CodeSimulatorArm64();
+  virtual ~CodeSimulatorArm64();
+
+  static constexpr bool CanSimulateArm64() {
+    return kCanSimulate;
+  }
+
+  void RunFrom(intptr_t code_buffer) OVERRIDE;
+
+  bool GetCReturnBool() OVERRIDE;
+  int32_t GetCReturnInt32() OVERRIDE;
+  int64_t GetCReturnInt64() OVERRIDE;
+
+ private:
+  vixl::Decoder* decoder_;
+  vixl::Simulator* simulator_;
+
+  // TODO: Enable CodeSimulatorArm64 for more host ISAs once vixl::Simulator supports
+  // them.
+  static constexpr bool kCanSimulate = (kRuntimeISA == kX86_64);
+};
+
+}  // namespace arm64
+}  // namespace art
+
+#endif  // ART_RUNTIME_SIMULATOR_CODE_SIMULATOR_ARM64_H_