| /* |
| * Copyright (C) 2018 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_builder.h" |
| |
| #include "dex/descriptors_names.h" |
| |
| #include <fstream> |
| #include <memory> |
| |
| #define DCHECK_NOT_NULL(p) DCHECK((p) != nullptr) |
| |
| namespace startop { |
| namespace dex { |
| |
| using std::shared_ptr; |
| using std::string; |
| |
| using ::dex::kAccPublic; |
| using Op = Instruction::Op; |
| |
| const TypeDescriptor TypeDescriptor::Int() { return TypeDescriptor{"I"}; }; |
| const TypeDescriptor TypeDescriptor::Void() { return TypeDescriptor{"V"}; }; |
| |
| namespace { |
| // From https://source.android.com/devices/tech/dalvik/dex-format#dex-file-magic |
| constexpr uint8_t kDexFileMagic[]{0x64, 0x65, 0x78, 0x0a, 0x30, 0x33, 0x38, 0x00}; |
| |
| // Strings lengths can be 32 bits long, but encoded as LEB128 this can take up to five bytes. |
| constexpr size_t kMaxEncodedStringLength{5}; |
| |
| } // namespace |
| |
| std::ostream& operator<<(std::ostream& out, const Instruction::Op& opcode) { |
| switch (opcode) { |
| case Instruction::Op::kReturn: |
| out << "kReturn"; |
| return out; |
| case Instruction::Op::kReturnObject: |
| out << "kReturnObject"; |
| return out; |
| case Instruction::Op::kMove: |
| out << "kMove"; |
| return out; |
| case Instruction::Op::kInvokeVirtual: |
| out << "kInvokeVirtual"; |
| return out; |
| case Instruction::Op::kInvokeDirect: |
| out << "kInvokeDirect"; |
| return out; |
| case Instruction::Op::kInvokeStatic: |
| out << "kInvokeStatic"; |
| return out; |
| case Instruction::Op::kInvokeInterface: |
| out << "kInvokeInterface"; |
| return out; |
| case Instruction::Op::kBindLabel: |
| out << "kBindLabel"; |
| return out; |
| case Instruction::Op::kBranchEqz: |
| out << "kBranchEqz"; |
| return out; |
| case Instruction::Op::kBranchNEqz: |
| out << "kBranchNEqz"; |
| return out; |
| case Instruction::Op::kNew: |
| out << "kNew"; |
| return out; |
| } |
| } |
| |
| std::ostream& operator<<(std::ostream& out, const Value& value) { |
| if (value.is_register()) { |
| out << "Register(" << value.value() << ")"; |
| } else if (value.is_parameter()) { |
| out << "Parameter(" << value.value() << ")"; |
| } else if (value.is_immediate()) { |
| out << "Immediate(" << value.value() << ")"; |
| } else if (value.is_string()) { |
| out << "String(" << value.value() << ")"; |
| } else if (value.is_label()) { |
| out << "Label(" << value.value() << ")"; |
| } else if (value.is_type()) { |
| out << "Type(" << value.value() << ")"; |
| } else { |
| out << "UnknownValue"; |
| } |
| return out; |
| } |
| |
| void* TrackingAllocator::Allocate(size_t size) { |
| std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(size); |
| void* raw_buffer = buffer.get(); |
| allocations_[raw_buffer] = std::move(buffer); |
| return raw_buffer; |
| } |
| |
| void TrackingAllocator::Free(void* ptr) { allocations_.erase(allocations_.find(ptr)); } |
| |
| // Write out a DEX file that is basically: |
| // |
| // package dextest; |
| // public class DexTest { |
| // public static int foo(String s) { return s.length(); } |
| // } |
| void WriteTestDexFile(const string& filename) { |
| DexBuilder dex_file; |
| |
| ClassBuilder cbuilder{dex_file.MakeClass("dextest.DexTest")}; |
| cbuilder.set_source_file("dextest.java"); |
| |
| TypeDescriptor string_type = TypeDescriptor::FromClassname("java.lang.String"); |
| |
| MethodBuilder method{cbuilder.CreateMethod("foo", Prototype{TypeDescriptor::Int(), string_type})}; |
| |
| Value result = method.MakeRegister(); |
| |
| MethodDeclData string_length = |
| dex_file.GetOrDeclareMethod(string_type, "length", Prototype{TypeDescriptor::Int()}); |
| |
| method.AddInstruction(Instruction::InvokeVirtual(string_length.id, result, Value::Parameter(0))); |
| method.BuildReturn(result); |
| |
| method.Encode(); |
| |
| slicer::MemView image{dex_file.CreateImage()}; |
| |
| std::ofstream out_file(filename); |
| out_file.write(image.ptr<const char>(), image.size()); |
| } |
| |
| TypeDescriptor TypeDescriptor::FromClassname(const std::string& name) { |
| return TypeDescriptor{art::DotToDescriptor(name.c_str())}; |
| } |
| |
| DexBuilder::DexBuilder() : dex_file_{std::make_shared<ir::DexFile>()} { |
| dex_file_->magic = slicer::MemView{kDexFileMagic, sizeof(kDexFileMagic)}; |
| } |
| |
| slicer::MemView DexBuilder::CreateImage() { |
| ::dex::Writer writer(dex_file_); |
| size_t image_size{0}; |
| ::dex::u1* image = writer.CreateImage(&allocator_, &image_size); |
| return slicer::MemView{image, image_size}; |
| } |
| |
| ir::String* DexBuilder::GetOrAddString(const std::string& string) { |
| ir::String*& entry = strings_[string]; |
| |
| if (entry == nullptr) { |
| // Need to encode the length and then write out the bytes, including 1 byte for null terminator |
| auto buffer = std::make_unique<uint8_t[]>(string.size() + kMaxEncodedStringLength + 1); |
| uint8_t* string_data_start = ::dex::WriteULeb128(buffer.get(), string.size()); |
| |
| size_t header_length = |
| reinterpret_cast<uintptr_t>(string_data_start) - reinterpret_cast<uintptr_t>(buffer.get()); |
| |
| auto end = std::copy(string.begin(), string.end(), string_data_start); |
| *end = '\0'; |
| |
| entry = Alloc<ir::String>(); |
| // +1 for null terminator |
| entry->data = slicer::MemView{buffer.get(), header_length + string.size() + 1}; |
| ::dex::u4 const new_index = dex_file_->strings_indexes.AllocateIndex(); |
| dex_file_->strings_map[new_index] = entry; |
| entry->orig_index = new_index; |
| string_data_.push_back(std::move(buffer)); |
| } |
| return entry; |
| } |
| |
| ClassBuilder DexBuilder::MakeClass(const std::string& name) { |
| auto* class_def = Alloc<ir::Class>(); |
| ir::Type* type_def = GetOrAddType(art::DotToDescriptor(name.c_str())); |
| type_def->class_def = class_def; |
| |
| class_def->type = type_def; |
| class_def->super_class = GetOrAddType(art::DotToDescriptor("java.lang.Object")); |
| class_def->access_flags = kAccPublic; |
| return ClassBuilder{this, name, class_def}; |
| } |
| |
| ir::Type* DexBuilder::GetOrAddType(const std::string& descriptor) { |
| if (types_by_descriptor_.find(descriptor) != types_by_descriptor_.end()) { |
| return types_by_descriptor_[descriptor]; |
| } |
| |
| ir::Type* type = Alloc<ir::Type>(); |
| type->descriptor = GetOrAddString(descriptor); |
| types_by_descriptor_[descriptor] = type; |
| type->orig_index = dex_file_->types_indexes.AllocateIndex(); |
| dex_file_->types_map[type->orig_index] = type; |
| return type; |
| } |
| |
| ir::Proto* Prototype::Encode(DexBuilder* dex) const { |
| auto* proto = dex->Alloc<ir::Proto>(); |
| proto->shorty = dex->GetOrAddString(Shorty()); |
| proto->return_type = dex->GetOrAddType(return_type_.descriptor()); |
| if (param_types_.size() > 0) { |
| proto->param_types = dex->Alloc<ir::TypeList>(); |
| for (const auto& param_type : param_types_) { |
| proto->param_types->types.push_back(dex->GetOrAddType(param_type.descriptor())); |
| } |
| } else { |
| proto->param_types = nullptr; |
| } |
| return proto; |
| } |
| |
| std::string Prototype::Shorty() const { |
| std::string shorty; |
| shorty.append(return_type_.short_descriptor()); |
| for (const auto& type_descriptor : param_types_) { |
| shorty.append(type_descriptor.short_descriptor()); |
| } |
| return shorty; |
| } |
| |
| ClassBuilder::ClassBuilder(DexBuilder* parent, const std::string& name, ir::Class* class_def) |
| : parent_(parent), type_descriptor_{TypeDescriptor::FromClassname(name)}, class_(class_def) {} |
| |
| MethodBuilder ClassBuilder::CreateMethod(const std::string& name, Prototype prototype) { |
| ir::MethodDecl* decl = parent_->GetOrDeclareMethod(type_descriptor_, name, prototype).decl; |
| |
| return MethodBuilder{parent_, class_, decl}; |
| } |
| |
| void ClassBuilder::set_source_file(const string& source) { |
| class_->source_file = parent_->GetOrAddString(source); |
| } |
| |
| MethodBuilder::MethodBuilder(DexBuilder* dex, ir::Class* class_def, ir::MethodDecl* decl) |
| : dex_{dex}, class_{class_def}, decl_{decl} {} |
| |
| ir::EncodedMethod* MethodBuilder::Encode() { |
| auto* method = dex_->Alloc<ir::EncodedMethod>(); |
| method->decl = decl_; |
| |
| // TODO: make access flags configurable |
| method->access_flags = kAccPublic | ::dex::kAccStatic; |
| |
| auto* code = dex_->Alloc<ir::Code>(); |
| DCHECK_NOT_NULL(decl_->prototype); |
| size_t const num_args = |
| decl_->prototype->param_types != nullptr ? decl_->prototype->param_types->types.size() : 0; |
| code->registers = num_registers_ + num_args; |
| code->ins_count = num_args; |
| EncodeInstructions(); |
| code->instructions = slicer::ArrayView<const ::dex::u2>(buffer_.data(), buffer_.size()); |
| size_t const return_count = decl_->prototype->return_type == dex_->GetOrAddType("V") ? 0 : 1; |
| code->outs_count = std::max(return_count, max_args_); |
| method->code = code; |
| |
| class_->direct_methods.push_back(method); |
| |
| return method; |
| } |
| |
| Value MethodBuilder::MakeRegister() { return Value::Local(num_registers_++); } |
| |
| Value MethodBuilder::MakeLabel() { |
| labels_.push_back({}); |
| return Value::Label(labels_.size() - 1); |
| } |
| |
| void MethodBuilder::AddInstruction(Instruction instruction) { |
| instructions_.push_back(instruction); |
| } |
| |
| void MethodBuilder::BuildReturn() { AddInstruction(Instruction::OpNoArgs(Op::kReturn)); } |
| |
| void MethodBuilder::BuildReturn(Value src, bool is_object) { |
| AddInstruction(Instruction::OpWithArgs( |
| is_object ? Op::kReturnObject : Op::kReturn, /*destination=*/{}, src)); |
| } |
| |
| void MethodBuilder::BuildConst4(Value target, int value) { |
| DCHECK_LT(value, 16); |
| AddInstruction(Instruction::OpWithArgs(Op::kMove, target, Value::Immediate(value))); |
| } |
| |
| void MethodBuilder::BuildConstString(Value target, const std::string& value) { |
| const ir::String* const dex_string = dex_->GetOrAddString(value); |
| AddInstruction(Instruction::OpWithArgs(Op::kMove, target, Value::String(dex_string->orig_index))); |
| } |
| |
| void MethodBuilder::EncodeInstructions() { |
| buffer_.clear(); |
| for (const auto& instruction : instructions_) { |
| EncodeInstruction(instruction); |
| } |
| } |
| |
| void MethodBuilder::EncodeInstruction(const Instruction& instruction) { |
| switch (instruction.opcode()) { |
| case Instruction::Op::kReturn: |
| return EncodeReturn(instruction, ::art::Instruction::RETURN); |
| case Instruction::Op::kReturnObject: |
| return EncodeReturn(instruction, ::art::Instruction::RETURN_OBJECT); |
| case Instruction::Op::kMove: |
| return EncodeMove(instruction); |
| case Instruction::Op::kInvokeVirtual: |
| return EncodeInvoke(instruction, art::Instruction::INVOKE_VIRTUAL); |
| case Instruction::Op::kInvokeDirect: |
| return EncodeInvoke(instruction, art::Instruction::INVOKE_DIRECT); |
| case Instruction::Op::kInvokeStatic: |
| return EncodeInvoke(instruction, art::Instruction::INVOKE_STATIC); |
| case Instruction::Op::kInvokeInterface: |
| return EncodeInvoke(instruction, art::Instruction::INVOKE_INTERFACE); |
| case Instruction::Op::kBindLabel: |
| return BindLabel(instruction.args()[0]); |
| case Instruction::Op::kBranchEqz: |
| return EncodeBranch(art::Instruction::IF_EQZ, instruction); |
| case Instruction::Op::kBranchNEqz: |
| return EncodeBranch(art::Instruction::IF_NEZ, instruction); |
| case Instruction::Op::kNew: |
| return EncodeNew(instruction); |
| } |
| } |
| |
| void MethodBuilder::EncodeReturn(const Instruction& instruction, ::art::Instruction::Code opcode) { |
| DCHECK(!instruction.dest().has_value()); |
| if (instruction.args().size() == 0) { |
| Encode10x(art::Instruction::RETURN_VOID); |
| } else { |
| DCHECK_EQ(1, instruction.args().size()); |
| size_t source = RegisterValue(instruction.args()[0]); |
| Encode11x(opcode, source); |
| } |
| } |
| |
| void MethodBuilder::EncodeMove(const Instruction& instruction) { |
| DCHECK_EQ(Instruction::Op::kMove, instruction.opcode()); |
| DCHECK(instruction.dest().has_value()); |
| DCHECK(instruction.dest()->is_register() || instruction.dest()->is_parameter()); |
| DCHECK_EQ(1, instruction.args().size()); |
| |
| const Value& source = instruction.args()[0]; |
| |
| if (source.is_immediate()) { |
| // TODO: support more registers |
| DCHECK_LT(RegisterValue(*instruction.dest()), 16); |
| Encode11n(art::Instruction::CONST_4, RegisterValue(*instruction.dest()), source.value()); |
| } else if (source.is_string()) { |
| constexpr size_t kMaxRegisters = 256; |
| DCHECK_LT(RegisterValue(*instruction.dest()), kMaxRegisters); |
| DCHECK_LT(source.value(), 65536); // make sure we don't need a jumbo string |
| Encode21c(::art::Instruction::CONST_STRING, RegisterValue(*instruction.dest()), source.value()); |
| } else { |
| UNIMPLEMENTED(FATAL); |
| } |
| } |
| |
| void MethodBuilder::EncodeInvoke(const Instruction& instruction, ::art::Instruction::Code opcode) { |
| constexpr size_t kMaxArgs = 5; |
| |
| CHECK_LE(instruction.args().size(), kMaxArgs); |
| |
| uint8_t arguments[kMaxArgs]{}; |
| for (size_t i = 0; i < instruction.args().size(); ++i) { |
| CHECK(instruction.args()[i].is_variable()); |
| arguments[i] = RegisterValue(instruction.args()[i]); |
| } |
| |
| Encode35c(opcode, |
| instruction.args().size(), |
| instruction.method_id(), |
| arguments[0], |
| arguments[1], |
| arguments[2], |
| arguments[3], |
| arguments[4]); |
| |
| // If there is a return value, add a move-result instruction |
| if (instruction.dest().has_value()) { |
| Encode11x(instruction.result_is_object() ? art::Instruction::MOVE_RESULT_OBJECT |
| : art::Instruction::MOVE_RESULT, |
| RegisterValue(*instruction.dest())); |
| } |
| |
| max_args_ = std::max(max_args_, instruction.args().size()); |
| } |
| |
| // Encodes a conditional branch that tests a single argument. |
| void MethodBuilder::EncodeBranch(art::Instruction::Code op, const Instruction& instruction) { |
| const auto& args = instruction.args(); |
| const auto& test_value = args[0]; |
| const auto& branch_target = args[1]; |
| CHECK_EQ(2, args.size()); |
| CHECK(test_value.is_variable()); |
| CHECK(branch_target.is_label()); |
| |
| size_t instruction_offset = buffer_.size(); |
| size_t field_offset = buffer_.size() + 1; |
| Encode21c( |
| op, RegisterValue(test_value), LabelValue(branch_target, instruction_offset, field_offset)); |
| } |
| |
| void MethodBuilder::EncodeNew(const Instruction& instruction) { |
| DCHECK_EQ(Instruction::Op::kNew, instruction.opcode()); |
| DCHECK(instruction.dest().has_value()); |
| DCHECK(instruction.dest()->is_variable()); |
| DCHECK_EQ(1, instruction.args().size()); |
| |
| const Value& type = instruction.args()[0]; |
| DCHECK_LT(RegisterValue(*instruction.dest()), 256); |
| DCHECK(type.is_type()); |
| Encode21c(::art::Instruction::NEW_INSTANCE, RegisterValue(*instruction.dest()), type.value()); |
| } |
| |
| size_t MethodBuilder::RegisterValue(const Value& value) const { |
| if (value.is_register()) { |
| return value.value(); |
| } else if (value.is_parameter()) { |
| return value.value() + num_registers_; |
| } |
| DCHECK(false && "Must be either a parameter or a register"); |
| return 0; |
| } |
| |
| void MethodBuilder::BindLabel(const Value& label_id) { |
| CHECK(label_id.is_label()); |
| |
| LabelData& label = labels_[label_id.value()]; |
| CHECK(!label.bound_address.has_value()); |
| |
| label.bound_address = buffer_.size(); |
| |
| // patch any forward references to this label. |
| for (const auto& ref : label.references) { |
| buffer_[ref.field_offset] = *label.bound_address - ref.instruction_offset; |
| } |
| // No point keeping these around anymore. |
| label.references.clear(); |
| } |
| |
| ::dex::u2 MethodBuilder::LabelValue(const Value& label_id, size_t instruction_offset, |
| size_t field_offset) { |
| CHECK(label_id.is_label()); |
| LabelData& label = labels_[label_id.value()]; |
| |
| // Short-circuit if the label is already bound. |
| if (label.bound_address.has_value()) { |
| return *label.bound_address - instruction_offset; |
| } |
| |
| // Otherwise, save a reference to where we need to back-patch later. |
| label.references.push_front(LabelReference{instruction_offset, field_offset}); |
| return 0; |
| } |
| |
| const MethodDeclData& DexBuilder::GetOrDeclareMethod(TypeDescriptor type, const std::string& name, |
| Prototype prototype) { |
| MethodDeclData& entry = method_id_map_[{type, name, prototype}]; |
| |
| if (entry.decl == nullptr) { |
| // This method has not already been declared, so declare it. |
| ir::MethodDecl* decl = dex_file_->Alloc<ir::MethodDecl>(); |
| // The method id is the last added method. |
| size_t id = dex_file_->methods.size() - 1; |
| |
| ir::String* dex_name{GetOrAddString(name)}; |
| decl->name = dex_name; |
| decl->parent = GetOrAddType(type.descriptor()); |
| decl->prototype = GetOrEncodeProto(prototype); |
| |
| // update the index -> ir node map (see tools/dexter/slicer/dex_ir_builder.cc) |
| auto new_index = dex_file_->methods_indexes.AllocateIndex(); |
| auto& ir_node = dex_file_->methods_map[new_index]; |
| SLICER_CHECK(ir_node == nullptr); |
| ir_node = decl; |
| decl->orig_index = decl->index = new_index; |
| |
| entry = {id, decl}; |
| } |
| |
| return entry; |
| } |
| |
| ir::Proto* DexBuilder::GetOrEncodeProto(Prototype prototype) { |
| ir::Proto*& ir_proto = proto_map_[prototype]; |
| if (ir_proto == nullptr) { |
| ir_proto = prototype.Encode(this); |
| } |
| return ir_proto; |
| } |
| |
| } // namespace dex |
| } // namespace startop |