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      1 /*
      2  * Copyright (C) 2011 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_ARCH_CONTEXT_H_
     18 #define ART_RUNTIME_ARCH_CONTEXT_H_
     19 
     20 #include <stddef.h>
     21 #include <stdint.h>
     22 
     23 #include "base/macros.h"
     24 
     25 namespace art {
     26 
     27 class QuickMethodFrameInfo;
     28 
     29 // Representation of a thread's context on the executing machine, used to implement long jumps in
     30 // the quick stack frame layout.
     31 class Context {
     32  public:
     33   // Creates a context for the running architecture
     34   static Context* Create();
     35 
     36   virtual ~Context() {}
     37 
     38   // Re-initializes the registers for context re-use.
     39   virtual void Reset() = 0;
     40 
     41   static uintptr_t* CalleeSaveAddress(uint8_t* frame, int num, size_t frame_size) {
     42     // Callee saves are held at the top of the frame
     43     uint8_t* save_addr = frame + frame_size - ((num + 1) * sizeof(void*));
     44 #if defined(__i386__) || defined(__x86_64__)
     45     save_addr -= sizeof(void*);  // account for return address
     46 #endif
     47     return reinterpret_cast<uintptr_t*>(save_addr);
     48   }
     49 
     50   // Reads values from callee saves in the given frame. The frame also holds
     51   // the method that holds the layout.
     52   virtual void FillCalleeSaves(uint8_t* frame, const QuickMethodFrameInfo& fr) = 0;
     53 
     54   // Sets the stack pointer value.
     55   virtual void SetSP(uintptr_t new_sp) = 0;
     56 
     57   // Sets the program counter value.
     58   virtual void SetPC(uintptr_t new_pc) = 0;
     59 
     60   // Sets the first argument register.
     61   virtual void SetArg0(uintptr_t new_arg0_value) = 0;
     62 
     63   // Returns whether the given GPR is accessible (read or write).
     64   virtual bool IsAccessibleGPR(uint32_t reg) = 0;
     65 
     66   // Gets the given GPRs address.
     67   virtual uintptr_t* GetGPRAddress(uint32_t reg) = 0;
     68 
     69   // Reads the given GPR. The caller is responsible for checking the register
     70   // is accessible with IsAccessibleGPR.
     71   virtual uintptr_t GetGPR(uint32_t reg) = 0;
     72 
     73   // Sets the given GPR. The caller is responsible for checking the register
     74   // is accessible with IsAccessibleGPR.
     75   virtual void SetGPR(uint32_t reg, uintptr_t value) = 0;
     76 
     77   // Returns whether the given FPR is accessible (read or write).
     78   virtual bool IsAccessibleFPR(uint32_t reg) = 0;
     79 
     80   // Reads the given FPR. The caller is responsible for checking the register
     81   // is accessible with IsAccessibleFPR.
     82   virtual uintptr_t GetFPR(uint32_t reg) = 0;
     83 
     84   // Sets the given FPR. The caller is responsible for checking the register
     85   // is accessible with IsAccessibleFPR.
     86   virtual void SetFPR(uint32_t reg, uintptr_t value) = 0;
     87 
     88   // Smashes the caller save registers. If we're throwing, we don't want to return bogus values.
     89   virtual void SmashCallerSaves() = 0;
     90 
     91   // Switches execution of the executing context to this context
     92   NO_RETURN virtual void DoLongJump() = 0;
     93 
     94   enum {
     95     kBadGprBase = 0xebad6070,
     96     kBadFprBase = 0xebad8070,
     97   };
     98 };
     99 
    100 }  // namespace art
    101 
    102 #endif  // ART_RUNTIME_ARCH_CONTEXT_H_
    103