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Diffstat (limited to 'runtime/dex_to_dex_decompiler.cc')
| -rw-r--r-- | runtime/dex_to_dex_decompiler.cc | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/runtime/dex_to_dex_decompiler.cc b/runtime/dex_to_dex_decompiler.cc new file mode 100644 index 0000000000..85d5784c7a --- /dev/null +++ b/runtime/dex_to_dex_decompiler.cc @@ -0,0 +1,208 @@ +/* + * Copyright (C) 2016 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 "dex_to_dex_decompiler.h" + +#include "base/logging.h" +#include "base/mutex.h" +#include "dex_file-inl.h" +#include "dex_instruction-inl.h" +#include "bytecode_utils.h" + +namespace art { +namespace optimizer { + +class DexDecompiler { + public: + DexDecompiler(const DexFile::CodeItem& code_item, + const ArrayRef<const uint8_t>& quickened_info, + bool decompile_return_instruction) + : code_item_(code_item), + quickened_info_ptr_(quickened_info.data()), + quickened_info_end_(quickened_info.data() + quickened_info.size()), + decompile_return_instruction_(decompile_return_instruction) {} + + bool Decompile(); + + private: + void DecompileInstanceFieldAccess(Instruction* inst, + uint32_t dex_pc, + Instruction::Code new_opcode) { + uint16_t index = GetIndexAt(dex_pc); + inst->SetOpcode(new_opcode); + inst->SetVRegC_22c(index); + } + + void DecompileInvokeVirtual(Instruction* inst, + uint32_t dex_pc, + Instruction::Code new_opcode, + bool is_range) { + uint16_t index = GetIndexAt(dex_pc); + inst->SetOpcode(new_opcode); + if (is_range) { + inst->SetVRegB_3rc(index); + } else { + inst->SetVRegB_35c(index); + } + } + + void DecompileNop(Instruction* inst, uint32_t dex_pc) { + if (quickened_info_ptr_ == quickened_info_end_) { + return; + } + const uint8_t* temporary_pointer = quickened_info_ptr_; + uint32_t quickened_pc = DecodeUnsignedLeb128(&temporary_pointer); + if (quickened_pc != dex_pc) { + return; + } + uint16_t reference_index = GetIndexAt(dex_pc); + uint16_t type_index = GetIndexAt(dex_pc); + inst->SetOpcode(Instruction::CHECK_CAST); + inst->SetVRegA_21c(reference_index); + inst->SetVRegB_21c(type_index); + } + + uint16_t GetIndexAt(uint32_t dex_pc) { + // Note that as a side effect, DecodeUnsignedLeb128 update the given pointer + // to the new position in the buffer. + DCHECK_LT(quickened_info_ptr_, quickened_info_end_); + uint32_t quickened_pc = DecodeUnsignedLeb128(&quickened_info_ptr_); + DCHECK_LT(quickened_info_ptr_, quickened_info_end_); + uint16_t index = DecodeUnsignedLeb128(&quickened_info_ptr_); + DCHECK_LE(quickened_info_ptr_, quickened_info_end_); + DCHECK_EQ(quickened_pc, dex_pc); + return index; + } + + const DexFile::CodeItem& code_item_; + const uint8_t* quickened_info_ptr_; + const uint8_t* const quickened_info_end_; + const bool decompile_return_instruction_; + + DISALLOW_COPY_AND_ASSIGN(DexDecompiler); +}; + +bool DexDecompiler::Decompile() { + // We need to iterate over the code item, and not over the quickening data, + // because the RETURN_VOID quickening is not encoded in the quickening data. Because + // unquickening is a rare need and not performance sensitive, it is not worth the + // added storage to also add the RETURN_VOID quickening in the quickened data. + for (CodeItemIterator it(code_item_); !it.Done(); it.Advance()) { + uint32_t dex_pc = it.CurrentDexPc(); + Instruction* inst = const_cast<Instruction*>(&it.CurrentInstruction()); + + switch (inst->Opcode()) { + case Instruction::RETURN_VOID_NO_BARRIER: + if (decompile_return_instruction_) { + inst->SetOpcode(Instruction::RETURN_VOID); + } + break; + + case Instruction::NOP: + DecompileNop(inst, dex_pc); + break; + + case Instruction::IGET_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET); + break; + + case Instruction::IGET_WIDE_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET_WIDE); + break; + + case Instruction::IGET_OBJECT_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET_OBJECT); + break; + + case Instruction::IGET_BOOLEAN_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET_BOOLEAN); + break; + + case Instruction::IGET_BYTE_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET_BYTE); + break; + + case Instruction::IGET_CHAR_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET_CHAR); + break; + + case Instruction::IGET_SHORT_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IGET_SHORT); + break; + + case Instruction::IPUT_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT); + break; + + case Instruction::IPUT_BOOLEAN_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT_BOOLEAN); + break; + + case Instruction::IPUT_BYTE_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT_BYTE); + break; + + case Instruction::IPUT_CHAR_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT_CHAR); + break; + + case Instruction::IPUT_SHORT_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT_SHORT); + break; + + case Instruction::IPUT_WIDE_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT_WIDE); + break; + + case Instruction::IPUT_OBJECT_QUICK: + DecompileInstanceFieldAccess(inst, dex_pc, Instruction::IPUT_OBJECT); + break; + + case Instruction::INVOKE_VIRTUAL_QUICK: + DecompileInvokeVirtual(inst, dex_pc, Instruction::INVOKE_VIRTUAL, false); + break; + + case Instruction::INVOKE_VIRTUAL_RANGE_QUICK: + DecompileInvokeVirtual(inst, dex_pc, Instruction::INVOKE_VIRTUAL_RANGE, true); + break; + + default: + break; + } + } + + if (quickened_info_ptr_ != quickened_info_end_) { + LOG(FATAL) << "Failed to use all values in quickening info." + << " Actual: " << std::hex << quickened_info_ptr_ + << " Expected: " << quickened_info_end_; + return false; + } + + return true; +} + +bool ArtDecompileDEX(const DexFile::CodeItem& code_item, + const ArrayRef<const uint8_t>& quickened_info, + bool decompile_return_instruction) { + if (quickened_info.size() == 0 && !decompile_return_instruction) { + return true; + } + DexDecompiler decompiler(code_item, quickened_info, decompile_return_instruction); + return decompiler.Decompile(); +} + +} // namespace optimizer +} // namespace art |