1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_RUNTIME_INTERPRETER_INTERPRETER_SWITCH_IMPL_H_
18 #define ART_RUNTIME_INTERPRETER_INTERPRETER_SWITCH_IMPL_H_
19 
20 #include "base/locks.h"
21 #include "base/macros.h"
22 #include "dex/dex_file.h"
23 #include "dex/code_item_accessors.h"
24 #include "jvalue.h"
25 #include "obj_ptr.h"
26 
27 namespace art {
28 
29 class ShadowFrame;
30 class Thread;
31 
32 namespace interpreter {
33 
34 // Group all the data that is needed in the switch interpreter.
35 // We need to pass it to the hand-written assembly and back,
36 // so it is easier to pass it through a single pointer.
37 // Similarly, returning the JValue type would be non-trivial.
38 struct SwitchImplContext {
39   Thread* self;
40   const CodeItemDataAccessor& accessor;
41   ShadowFrame& shadow_frame;
42   JValue& result_register;
43   bool interpret_one_instruction;
44   JValue result;
45 };
46 
47 // The actual internal implementation of the switch interpreter.
48 template<bool do_access_check, bool transaction_active>
49 void ExecuteSwitchImplCpp(SwitchImplContext* ctx)
50   REQUIRES_SHARED(Locks::mutator_lock_);
51 
52 // Hand-written assembly method which wraps the C++ implementation,
53 // while defining the DEX PC in the CFI so that libunwind can resolve it.
54 extern "C" void ExecuteSwitchImplAsm(SwitchImplContext* ctx, void* impl, const uint16_t* dexpc)
55   REQUIRES_SHARED(Locks::mutator_lock_);
56 
57 // Wrapper around the switch interpreter which ensures we can unwind through it.
58 template<bool do_access_check, bool transaction_active>
59 ALWAYS_INLINE JValue ExecuteSwitchImpl(Thread* self, const CodeItemDataAccessor& accessor,
60                                        ShadowFrame& shadow_frame, JValue result_register,
61                                        bool interpret_one_instruction)
62   REQUIRES_SHARED(Locks::mutator_lock_) {
63   SwitchImplContext ctx {
64     .self = self,
65     .accessor = accessor,
66     .shadow_frame = shadow_frame,
67     .result_register = result_register,
68     .interpret_one_instruction = interpret_one_instruction,
69     .result = JValue(),
70   };
71   void* impl = reinterpret_cast<void*>(&ExecuteSwitchImplCpp<do_access_check, transaction_active>);
72   const uint16_t* dex_pc = ctx.accessor.Insns();
73   ExecuteSwitchImplAsm(&ctx, impl, dex_pc);
74   return ctx.result;
75 }
76 
77 }  // namespace interpreter
78 }  // namespace art
79 
80 #endif  // ART_RUNTIME_INTERPRETER_INTERPRETER_SWITCH_IMPL_H_
81