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      1 /*
      2  * Copyright (C) 2015 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_COMPILER_LINKER_ARM64_RELATIVE_PATCHER_ARM64_H_
     18 #define ART_COMPILER_LINKER_ARM64_RELATIVE_PATCHER_ARM64_H_
     19 
     20 #include "base/array_ref.h"
     21 #include "base/bit_field.h"
     22 #include "linker/arm/relative_patcher_arm_base.h"
     23 
     24 namespace art {
     25 namespace linker {
     26 
     27 class Arm64RelativePatcher FINAL : public ArmBaseRelativePatcher {
     28  public:
     29   enum class BakerReadBarrierKind : uint8_t {
     30     kField,   // Field get or array get with constant offset (i.e. constant index).
     31     kGcRoot,  // GC root load.
     32     kLast
     33   };
     34 
     35   static uint32_t EncodeBakerReadBarrierFieldData(uint32_t base_reg, uint32_t holder_reg) {
     36     CheckValidReg(base_reg);
     37     CheckValidReg(holder_reg);
     38     return BakerReadBarrierKindField::Encode(BakerReadBarrierKind::kField) |
     39            BakerReadBarrierFirstRegField::Encode(base_reg) |
     40            BakerReadBarrierSecondRegField::Encode(holder_reg);
     41   }
     42 
     43   static uint32_t EncodeBakerReadBarrierGcRootData(uint32_t root_reg) {
     44     CheckValidReg(root_reg);
     45     return BakerReadBarrierKindField::Encode(BakerReadBarrierKind::kGcRoot) |
     46            BakerReadBarrierFirstRegField::Encode(root_reg) |
     47            BakerReadBarrierSecondRegField::Encode(kInvalidEncodedReg);
     48   }
     49 
     50   Arm64RelativePatcher(RelativePatcherTargetProvider* provider,
     51                        const Arm64InstructionSetFeatures* features);
     52 
     53   uint32_t ReserveSpace(uint32_t offset,
     54                         const CompiledMethod* compiled_method,
     55                         MethodReference method_ref) OVERRIDE;
     56   uint32_t ReserveSpaceEnd(uint32_t offset) OVERRIDE;
     57   uint32_t WriteThunks(OutputStream* out, uint32_t offset) OVERRIDE;
     58   void PatchCall(std::vector<uint8_t>* code,
     59                  uint32_t literal_offset,
     60                  uint32_t patch_offset,
     61                  uint32_t target_offset) OVERRIDE;
     62   void PatchPcRelativeReference(std::vector<uint8_t>* code,
     63                                 const LinkerPatch& patch,
     64                                 uint32_t patch_offset,
     65                                 uint32_t target_offset) OVERRIDE;
     66   void PatchBakerReadBarrierBranch(std::vector<uint8_t>* code,
     67                                    const LinkerPatch& patch,
     68                                    uint32_t patch_offset) OVERRIDE;
     69 
     70  protected:
     71   static constexpr uint32_t kInvalidEncodedReg = /* sp/zr is invalid */ 31u;
     72 
     73   ThunkKey GetBakerReadBarrierKey(const LinkerPatch& patch) OVERRIDE;
     74   std::vector<uint8_t> CompileThunk(const ThunkKey& key) OVERRIDE;
     75   uint32_t MaxPositiveDisplacement(ThunkType type) OVERRIDE;
     76   uint32_t MaxNegativeDisplacement(ThunkType type) OVERRIDE;
     77 
     78  private:
     79   static constexpr size_t kBitsForBakerReadBarrierKind =
     80       MinimumBitsToStore(static_cast<size_t>(BakerReadBarrierKind::kLast));
     81   static constexpr size_t kBitsForRegister = 5u;
     82   using BakerReadBarrierKindField =
     83       BitField<BakerReadBarrierKind, 0, kBitsForBakerReadBarrierKind>;
     84   using BakerReadBarrierFirstRegField =
     85       BitField<uint32_t, kBitsForBakerReadBarrierKind, kBitsForRegister>;
     86   using BakerReadBarrierSecondRegField =
     87       BitField<uint32_t, kBitsForBakerReadBarrierKind + kBitsForRegister, kBitsForRegister>;
     88 
     89   static void CheckValidReg(uint32_t reg) {
     90     DCHECK(reg < 30u && reg != 16u && reg != 17u);
     91   }
     92 
     93   static uint32_t PatchAdrp(uint32_t adrp, uint32_t disp);
     94 
     95   static bool NeedsErratum843419Thunk(ArrayRef<const uint8_t> code, uint32_t literal_offset,
     96                                       uint32_t patch_offset);
     97   void SetInsn(std::vector<uint8_t>* code, uint32_t offset, uint32_t value);
     98   static uint32_t GetInsn(ArrayRef<const uint8_t> code, uint32_t offset);
     99 
    100   template <typename Alloc>
    101   static uint32_t GetInsn(std::vector<uint8_t, Alloc>* code, uint32_t offset);
    102 
    103   const bool fix_cortex_a53_843419_;
    104   // Map original patch_offset to thunk offset.
    105   std::vector<std::pair<uint32_t, uint32_t>> adrp_thunk_locations_;
    106   size_t reserved_adrp_thunks_;
    107   size_t processed_adrp_thunks_;
    108   std::vector<uint8_t> current_method_thunks_;
    109 
    110   friend class Arm64RelativePatcherTest;
    111 
    112   DISALLOW_COPY_AND_ASSIGN(Arm64RelativePatcher);
    113 };
    114 
    115 }  // namespace linker
    116 }  // namespace art
    117 
    118 #endif  // ART_COMPILER_LINKER_ARM64_RELATIVE_PATCHER_ARM64_H_
    119