diff options
Diffstat (limited to 'compiler/optimizing')
| -rw-r--r-- | compiler/optimizing/code_generator_arm64.cc | 909 | ||||
| -rw-r--r-- | compiler/optimizing/code_generator_arm64.h | 45 | ||||
| -rw-r--r-- | compiler/optimizing/intrinsics_arm64.cc | 46 | ||||
| -rw-r--r-- | compiler/optimizing/optimizing_compiler.cc | 5 |
4 files changed, 849 insertions, 156 deletions
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc index d82cb672a0..397b3be6ec 100644 --- a/compiler/optimizing/code_generator_arm64.cc +++ b/compiler/optimizing/code_generator_arm64.cc @@ -42,6 +42,9 @@ using namespace vixl; // NOLINT(build/namespaces) namespace art { +template<class MirrorType> +class GcRoot; + namespace arm64 { using helpers::CPURegisterFrom; @@ -431,15 +434,6 @@ class TypeCheckSlowPathARM64 : public SlowPathCodeARM64 { __ Bind(GetEntryLabel()); - if (instruction_->IsCheckCast()) { - // The codegen for the instruction overwrites `temp`, so put it back in place. - Register obj = InputRegisterAt(instruction_, 0); - Register temp = WRegisterFrom(locations->GetTemp(0)); - uint32_t class_offset = mirror::Object::ClassOffset().Int32Value(); - __ Ldr(temp, HeapOperand(obj, class_offset)); - arm64_codegen->GetAssembler()->MaybeUnpoisonHeapReference(temp); - } - if (!is_fatal_) { SaveLiveRegisters(codegen, locations); } @@ -571,6 +565,271 @@ void JumpTableARM64::EmitTable(CodeGeneratorARM64* codegen) { } } +// Slow path generating a read barrier for a heap reference. +class ReadBarrierForHeapReferenceSlowPathARM64 : public SlowPathCodeARM64 { + public: + ReadBarrierForHeapReferenceSlowPathARM64(HInstruction* instruction, + Location out, + Location ref, + Location obj, + uint32_t offset, + Location index) + : instruction_(instruction), + out_(out), + ref_(ref), + obj_(obj), + offset_(offset), + index_(index) { + DCHECK(kEmitCompilerReadBarrier); + // If `obj` is equal to `out` or `ref`, it means the initial object + // has been overwritten by (or after) the heap object reference load + // to be instrumented, e.g.: + // + // __ Ldr(out, HeapOperand(out, class_offset); + // codegen_->GenerateReadBarrier(instruction, out_loc, out_loc, out_loc, offset); + // + // In that case, we have lost the information about the original + // object, and the emitted read barrier cannot work properly. + DCHECK(!obj.Equals(out)) << "obj=" << obj << " out=" << out; + DCHECK(!obj.Equals(ref)) << "obj=" << obj << " ref=" << ref; + } + + void EmitNativeCode(CodeGenerator* codegen) OVERRIDE { + CodeGeneratorARM64* arm64_codegen = down_cast<CodeGeneratorARM64*>(codegen); + LocationSummary* locations = instruction_->GetLocations(); + Primitive::Type type = Primitive::kPrimNot; + DCHECK(locations->CanCall()); + DCHECK(!locations->GetLiveRegisters()->ContainsCoreRegister(out_.reg())); + DCHECK(!instruction_->IsInvoke() || + (instruction_->IsInvokeStaticOrDirect() && + instruction_->GetLocations()->Intrinsified())); + + __ Bind(GetEntryLabel()); + + // Note: In the case of a HArrayGet instruction, when the base + // address is a HArm64IntermediateAddress instruction, it does not + // point to the array object itself, but to an offset within this + // object. However, the read barrier entry point needs the array + // object address to be passed as first argument. So we + // temporarily set back `obj_` to that address, and restore its + // initial value later. + if (instruction_->IsArrayGet() && + instruction_->AsArrayGet()->GetArray()->IsArm64IntermediateAddress()) { + if (kIsDebugBuild) { + HArm64IntermediateAddress* intermediate_address = + instruction_->AsArrayGet()->GetArray()->AsArm64IntermediateAddress(); + uint32_t intermediate_address_offset = + intermediate_address->GetOffset()->AsIntConstant()->GetValueAsUint64(); + DCHECK_EQ(intermediate_address_offset, offset_); + DCHECK_EQ(mirror::Array::DataOffset(Primitive::ComponentSize(type)).Uint32Value(), offset_); + } + Register obj_reg = RegisterFrom(obj_, Primitive::kPrimInt); + __ Sub(obj_reg, obj_reg, offset_); + } + + SaveLiveRegisters(codegen, locations); + + // We may have to change the index's value, but as `index_` is a + // constant member (like other "inputs" of this slow path), + // introduce a copy of it, `index`. + Location index = index_; + if (index_.IsValid()) { + // Handle `index_` for HArrayGet and intrinsic UnsafeGetObject. + if (instruction_->IsArrayGet()) { + // Compute the actual memory offset and store it in `index`. + Register index_reg = RegisterFrom(index_, Primitive::kPrimInt); + DCHECK(locations->GetLiveRegisters()->ContainsCoreRegister(index_.reg())); + if (codegen->IsCoreCalleeSaveRegister(index_.reg())) { + // We are about to change the value of `index_reg` (see the + // calls to vixl::MacroAssembler::Lsl and + // vixl::MacroAssembler::Mov below), but it has + // not been saved by the previous call to + // art::SlowPathCode::SaveLiveRegisters, as it is a + // callee-save register -- + // art::SlowPathCode::SaveLiveRegisters does not consider + // callee-save registers, as it has been designed with the + // assumption that callee-save registers are supposed to be + // handled by the called function. So, as a callee-save + // register, `index_reg` _would_ eventually be saved onto + // the stack, but it would be too late: we would have + // changed its value earlier. Therefore, we manually save + // it here into another freely available register, + // `free_reg`, chosen of course among the caller-save + // registers (as a callee-save `free_reg` register would + // exhibit the same problem). + // + // Note we could have requested a temporary register from + // the register allocator instead; but we prefer not to, as + // this is a slow path, and we know we can find a + // caller-save register that is available. + Register free_reg = FindAvailableCallerSaveRegister(codegen); + __ Mov(free_reg.W(), index_reg); + index_reg = free_reg; + index = LocationFrom(index_reg); + } else { + // The initial register stored in `index_` has already been + // saved in the call to art::SlowPathCode::SaveLiveRegisters + // (as it is not a callee-save register), so we can freely + // use it. + } + // Shifting the index value contained in `index_reg` by the scale + // factor (2) cannot overflow in practice, as the runtime is + // unable to allocate object arrays with a size larger than + // 2^26 - 1 (that is, 2^28 - 4 bytes). + __ Lsl(index_reg, index_reg, Primitive::ComponentSizeShift(type)); + static_assert( + sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t), + "art::mirror::HeapReference<art::mirror::Object> and int32_t have different sizes."); + __ Add(index_reg, index_reg, Operand(offset_)); + } else { + DCHECK(instruction_->IsInvoke()); + DCHECK(instruction_->GetLocations()->Intrinsified()); + DCHECK((instruction_->AsInvoke()->GetIntrinsic() == Intrinsics::kUnsafeGetObject) || + (instruction_->AsInvoke()->GetIntrinsic() == Intrinsics::kUnsafeGetObjectVolatile)) + << instruction_->AsInvoke()->GetIntrinsic(); + DCHECK_EQ(offset_, 0U); + DCHECK(index_.IsRegisterPair()); + // UnsafeGet's offset location is a register pair, the low + // part contains the correct offset. + index = index_.ToLow(); + } + } + + // We're moving two or three locations to locations that could + // overlap, so we need a parallel move resolver. + InvokeRuntimeCallingConvention calling_convention; + HParallelMove parallel_move(codegen->GetGraph()->GetArena()); + parallel_move.AddMove(ref_, + LocationFrom(calling_convention.GetRegisterAt(0)), + type, + nullptr); + parallel_move.AddMove(obj_, + LocationFrom(calling_convention.GetRegisterAt(1)), + type, + nullptr); + if (index.IsValid()) { + parallel_move.AddMove(index, + LocationFrom(calling_convention.GetRegisterAt(2)), + Primitive::kPrimInt, + nullptr); + codegen->GetMoveResolver()->EmitNativeCode(¶llel_move); + } else { + codegen->GetMoveResolver()->EmitNativeCode(¶llel_move); + arm64_codegen->MoveConstant(LocationFrom(calling_convention.GetRegisterAt(2)), offset_); + } + arm64_codegen->InvokeRuntime(QUICK_ENTRY_POINT(pReadBarrierSlow), + instruction_, + instruction_->GetDexPc(), + this); + CheckEntrypointTypes< + kQuickReadBarrierSlow, mirror::Object*, mirror::Object*, mirror::Object*, uint32_t>(); + arm64_codegen->MoveLocation(out_, calling_convention.GetReturnLocation(type), type); + + RestoreLiveRegisters(codegen, locations); + + // Restore the value of `obj_` when it corresponds to a + // HArm64IntermediateAddress instruction. + if (instruction_->IsArrayGet() && + instruction_->AsArrayGet()->GetArray()->IsArm64IntermediateAddress()) { + if (kIsDebugBuild) { + HArm64IntermediateAddress* intermediate_address = + instruction_->AsArrayGet()->GetArray()->AsArm64IntermediateAddress(); + uint32_t intermediate_address_offset = + intermediate_address->GetOffset()->AsIntConstant()->GetValueAsUint64(); + DCHECK_EQ(intermediate_address_offset, offset_); + DCHECK_EQ(mirror::Array::DataOffset(Primitive::ComponentSize(type)).Uint32Value(), offset_); + } + Register obj_reg = RegisterFrom(obj_, Primitive::kPrimInt); + __ Add(obj_reg, obj_reg, offset_); + } + + __ B(GetExitLabel()); + } + + const char* GetDescription() const OVERRIDE { return "ReadBarrierForHeapReferenceSlowPathARM64"; } + + private: + Register FindAvailableCallerSaveRegister(CodeGenerator* codegen) { + size_t ref = static_cast<int>(XRegisterFrom(ref_).code()); + size_t obj = static_cast<int>(XRegisterFrom(obj_).code()); + for (size_t i = 0, e = codegen->GetNumberOfCoreRegisters(); i < e; ++i) { + if (i != ref && i != obj && !codegen->IsCoreCalleeSaveRegister(i)) { + return Register(VIXLRegCodeFromART(i), kXRegSize); + } + } + // We shall never fail to find a free caller-save register, as + // there are more than two core caller-save registers on ARM64 + // (meaning it is possible to find one which is different from + // `ref` and `obj`). + DCHECK_GT(codegen->GetNumberOfCoreCallerSaveRegisters(), 2u); + LOG(FATAL) << "Could not find a free register"; + UNREACHABLE(); + } + + HInstruction* const instruction_; + const Location out_; + const Location ref_; + const Location obj_; + const uint32_t offset_; + // An additional location containing an index to an array. + // Only used for HArrayGet and the UnsafeGetObject & + // UnsafeGetObjectVolatile intrinsics. + const Location index_; + + DISALLOW_COPY_AND_ASSIGN(ReadBarrierForHeapReferenceSlowPathARM64); +}; + +// Slow path generating a read barrier for a GC root. +class ReadBarrierForRootSlowPathARM64 : public SlowPathCodeARM64 { + public: + ReadBarrierForRootSlowPathARM64(HInstruction* instruction, Location out, Location root) + : instruction_(instruction), out_(out), root_(root) {} + + void EmitNativeCode(CodeGenerator* codegen) OVERRIDE { + LocationSummary* locations = instruction_->GetLocations(); + Primitive::Type type = Primitive::kPrimNot; + DCHECK(locations->CanCall()); + DCHECK(!locations->GetLiveRegisters()->ContainsCoreRegister(out_.reg())); + DCHECK(instruction_->IsLoadClass() || instruction_->IsLoadString()); + + __ Bind(GetEntryLabel()); + SaveLiveRegisters(codegen, locations); + + InvokeRuntimeCallingConvention calling_convention; + CodeGeneratorARM64* arm64_codegen = down_cast<CodeGeneratorARM64*>(codegen); + // The argument of the ReadBarrierForRootSlow is not a managed + // reference (`mirror::Object*`), but a `GcRoot<mirror::Object>*`; + // thus we need a 64-bit move here, and we cannot use + // + // arm64_codegen->MoveLocation( + // LocationFrom(calling_convention.GetRegisterAt(0)), + // root_, + // type); + // + // which would emit a 32-bit move, as `type` is a (32-bit wide) + // reference type (`Primitive::kPrimNot`). + __ Mov(calling_convention.GetRegisterAt(0), XRegisterFrom(out_)); + arm64_codegen->InvokeRuntime(QUICK_ENTRY_POINT(pReadBarrierForRootSlow), + instruction_, + instruction_->GetDexPc(), + this); + CheckEntrypointTypes<kQuickReadBarrierForRootSlow, mirror::Object*, GcRoot<mirror::Object>*>(); + arm64_codegen->MoveLocation(out_, calling_convention.GetReturnLocation(type), type); + + RestoreLiveRegisters(codegen, locations); + __ B(GetExitLabel()); + } + + const char* GetDescription() const OVERRIDE { return "ReadBarrierForRootSlowPathARM64"; } + + private: + HInstruction* const instruction_; + const Location out_; + const Location root_; + + DISALLOW_COPY_AND_ASSIGN(ReadBarrierForRootSlowPathARM64); +}; + #undef __ Location InvokeDexCallingConventionVisitorARM64::GetNextLocation(Primitive::Type type) { @@ -1401,13 +1660,25 @@ void LocationsBuilderARM64::HandleBinaryOp(HBinaryOperation* instr) { } void LocationsBuilderARM64::HandleFieldGet(HInstruction* instruction) { + DCHECK(instruction->IsInstanceFieldGet() || instruction->IsStaticFieldGet()); + + bool object_field_get_with_read_barrier = + kEmitCompilerReadBarrier && (instruction->GetType() == Primitive::kPrimNot); LocationSummary* locations = - new (GetGraph()->GetArena()) LocationSummary(instruction, LocationSummary::kNoCall); + new (GetGraph()->GetArena()) LocationSummary(instruction, + object_field_get_with_read_barrier ? + LocationSummary::kCallOnSlowPath : + LocationSummary::kNoCall); locations->SetInAt(0, Location::RequiresRegister()); if (Primitive::IsFloatingPointType(instruction->GetType())) { locations->SetOut(Location::RequiresFpuRegister()); } else { - locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap); + // The output overlaps for an object field get when read barriers + // are enabled: we do not want the load to overwrite the object's + // location, as we need it to emit the read barrier. + locations->SetOut( + Location::RequiresRegister(), + object_field_get_with_read_barrier ? Location::kOutputOverlap : Location::kNoOutputOverlap); } } @@ -1436,7 +1707,11 @@ void InstructionCodeGeneratorARM64::HandleFieldGet(HInstruction* instruction, } if (field_type == Primitive::kPrimNot) { - GetAssembler()->MaybeUnpoisonHeapReference(OutputCPURegister(instruction).W()); + LocationSummary* locations = instruction->GetLocations(); + Location base = locations->InAt(0); + Location out = locations->Out(); + uint32_t offset = field_info.GetFieldOffset().Uint32Value(); + codegen_->MaybeGenerateReadBarrier(instruction, out, out, base, offset); } } @@ -1670,22 +1945,33 @@ void InstructionCodeGeneratorARM64::VisitArm64MultiplyAccumulate(HArm64MultiplyA } void LocationsBuilderARM64::VisitArrayGet(HArrayGet* instruction) { + bool object_array_get_with_read_barrier = + kEmitCompilerReadBarrier && (instruction->GetType() == Primitive::kPrimNot); LocationSummary* locations = - new (GetGraph()->GetArena()) LocationSummary(instruction, LocationSummary::kNoCall); + new (GetGraph()->GetArena()) LocationSummary(instruction, + object_array_get_with_read_barrier ? + LocationSummary::kCallOnSlowPath : + LocationSummary::kNoCall); locations->SetInAt(0, Location::RequiresRegister()); locations->SetInAt(1, Location::RegisterOrConstant(instruction->InputAt(1))); if (Primitive::IsFloatingPointType(instruction->GetType())) { locations->SetOut(Location::RequiresFpuRegister(), Location::kNoOutputOverlap); } else { - locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap); + // The output overlaps in the case of an object array get with + // read barriers enabled: we do not want the move to overwrite the + // array's location, as we need it to emit the read barrier. + locations->SetOut( + Location::RequiresRegister(), + object_array_get_with_read_barrier ? Location::kOutputOverlap : Location::kNoOutputOverlap); } } void InstructionCodeGeneratorARM64::VisitArrayGet(HArrayGet* instruction) { Primitive::Type type = instruction->GetType(); Register obj = InputRegisterAt(instruction, 0); - Location index = instruction->GetLocations()->InAt(1); - size_t offset = mirror::Array::DataOffset(Primitive::ComponentSize(type)).Uint32Value(); + LocationSummary* locations = instruction->GetLocations(); + Location index = locations->InAt(1); + uint32_t offset = mirror::Array::DataOffset(Primitive::ComponentSize(type)).Uint32Value(); MemOperand source = HeapOperand(obj); CPURegister dest = OutputCPURegister(instruction); @@ -1717,8 +2003,22 @@ void InstructionCodeGeneratorARM64::VisitArrayGet(HArrayGet* instruction) { codegen_->Load(type, dest, source); codegen_->MaybeRecordImplicitNullCheck(instruction); - if (instruction->GetType() == Primitive::kPrimNot) { - GetAssembler()->MaybeUnpoisonHeapReference(dest.W()); + if (type == Primitive::kPrimNot) { + static_assert( + sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t), + "art::mirror::HeapReference<art::mirror::Object> and int32_t have different sizes."); + Location obj_loc = locations->InAt(0); + Location out = locations->Out(); + if (index.IsConstant()) { + codegen_->MaybeGenerateReadBarrier(instruction, out, out, obj_loc, offset); + } else { + // Note: when `obj_loc` is a HArm64IntermediateAddress, it does + // not contain the base address of the array object, which is + // needed by the read barrier entry point. So the read barrier + // slow path will temporarily set back `obj_loc` to the right + // address (see ReadBarrierForHeapReferenceSlowPathARM64::EmitNativeCode). + codegen_->MaybeGenerateReadBarrier(instruction, out, out, obj_loc, offset, index); + } } } @@ -1736,12 +2036,19 @@ void InstructionCodeGeneratorARM64::VisitArrayLength(HArrayLength* instruction) } void LocationsBuilderARM64::VisitArraySet(HArraySet* instruction) { + Primitive::Type value_type = instruction->GetComponentType(); + + bool may_need_runtime_call_for_type_check = instruction->NeedsTypeCheck(); + bool object_array_set_with_read_barrier = + kEmitCompilerReadBarrier && (value_type == Primitive::kPrimNot); LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary( instruction, - instruction->NeedsTypeCheck() ? LocationSummary::kCallOnSlowPath : LocationSummary::kNoCall); + (may_need_runtime_call_for_type_check || object_array_set_with_read_barrier) ? + LocationSummary::kCallOnSlowPath : + LocationSummary::kNoCall); locations->SetInAt(0, Location::RequiresRegister()); locations->SetInAt(1, Location::RegisterOrConstant(instruction->InputAt(1))); - if (Primitive::IsFloatingPointType(instruction->InputAt(2)->GetType())) { + if (Primitive::IsFloatingPointType(value_type)) { locations->SetInAt(2, Location::RequiresFpuRegister()); } else { locations->SetInAt(2, Location::RequiresRegister()); @@ -1751,7 +2058,7 @@ void LocationsBuilderARM64::VisitArraySet(HArraySet* instruction) { void InstructionCodeGeneratorARM64::VisitArraySet(HArraySet* instruction) { Primitive::Type value_type = instruction->GetComponentType(); LocationSummary* locations = instruction->GetLocations(); - bool may_need_runtime_call = locations->CanCall(); + bool may_need_runtime_call_for_type_check = instruction->NeedsTypeCheck(); bool needs_write_barrier = CodeGenerator::StoreNeedsWriteBarrier(value_type, instruction->GetValue()); @@ -1765,7 +2072,7 @@ void InstructionCodeGeneratorARM64::VisitArraySet(HArraySet* instruction) { BlockPoolsScope block_pools(masm); if (!needs_write_barrier) { - DCHECK(!may_need_runtime_call); + DCHECK(!may_need_runtime_call_for_type_check); if (index.IsConstant()) { offset += Int64ConstantFrom(index) << Primitive::ComponentSizeShift(value_type); destination = HeapOperand(array, offset); @@ -1815,7 +2122,7 @@ void InstructionCodeGeneratorARM64::VisitArraySet(HArraySet* instruction) { uint32_t super_offset = mirror::Class::SuperClassOffset().Int32Value(); uint32_t component_offset = mirror::Class::ComponentTypeOffset().Int32Value(); - if (may_need_runtime_call) { + if (may_need_runtime_call_for_type_check) { slow_path = new (GetGraph()->GetArena()) ArraySetSlowPathARM64(instruction); codegen_->AddSlowPath(slow_path); if (instruction->GetValueCanBeNull()) { @@ -1830,26 +2137,66 @@ void InstructionCodeGeneratorARM64::VisitArraySet(HArraySet* instruction) { __ Bind(&non_zero); } - Register temp2 = temps.AcquireSameSizeAs(array); - __ Ldr(temp, HeapOperand(array, class_offset)); - codegen_->MaybeRecordImplicitNullCheck(instruction); - GetAssembler()->MaybeUnpoisonHeapReference(temp); - __ Ldr(temp, HeapOperand(temp, component_offset)); - __ Ldr(temp2, HeapOperand(Register(value), class_offset)); - // No need to poison/unpoison, we're comparing two poisoned references. - __ Cmp(temp, temp2); - if (instruction->StaticTypeOfArrayIsObjectArray()) { - vixl::Label do_put; - __ B(eq, &do_put); - GetAssembler()->MaybeUnpoisonHeapReference(temp); - __ Ldr(temp, HeapOperand(temp, super_offset)); - // No need to unpoison, we're comparing against null. - __ Cbnz(temp, slow_path->GetEntryLabel()); - __ Bind(&do_put); + if (kEmitCompilerReadBarrier) { + // When read barriers are enabled, the type checking + // instrumentation requires two read barriers: + // + // __ Mov(temp2, temp); + // // /* HeapReference<Class> */ temp = temp->component_type_ + // __ Ldr(temp, HeapOperand(temp, component_offset)); + // codegen_->GenerateReadBarrier( + // instruction, temp_loc, temp_loc, temp2_loc, component_offset); + // + // // /* HeapReference<Class> */ temp2 = value->klass_ + // __ Ldr(temp2, HeapOperand(Register(value), class_offset)); + // codegen_->GenerateReadBarrier( + // instruction, temp2_loc, temp2_loc, value_loc, class_offset, temp_loc); + // + // __ Cmp(temp, temp2); + // + // However, the second read barrier may trash `temp`, as it + // is a temporary register, and as such would not be saved + // along with live registers before calling the runtime (nor + // restored afterwards). So in this case, we bail out and + // delegate the work to the array set slow path. + // + // TODO: Extend the register allocator to support a new + // "(locally) live temp" location so as to avoid always + // going into the slow path when read barriers are enabled. + __ B(slow_path->GetEntryLabel()); } else { - __ B(ne, slow_path->GetEntryLabel()); + Register temp2 = temps.AcquireSameSizeAs(array); + // /* HeapReference<Class> */ temp = array->klass_ + __ Ldr(temp, HeapOperand(array, class_offset)); + codegen_->MaybeRecordImplicitNullCheck(instruction); + GetAssembler()->MaybeUnpoisonHeapReference(temp); + + // /* HeapReference<Class> */ temp = temp->component_type_ + __ Ldr(temp, HeapOperand(temp, component_offset)); + // /* HeapReference<Class> */ temp2 = value->klass_ + __ Ldr(temp2, HeapOperand(Register(value), class_offset)); + // If heap poisoning is enabled, no need to unpoison `temp` + // nor `temp2`, as we are comparing two poisoned references. + __ Cmp(temp, temp2); + + if (instruction->StaticTypeOfArrayIsObjectArray()) { + vixl::Label do_put; + __ B(eq, &do_put); + // If heap poisoning is enabled, the `temp` reference has + // not been unpoisoned yet; unpoison it now. + GetAssembler()->MaybeUnpoisonHeapReference(temp); + + // /* HeapReference<Class> */ temp = temp->super_class_ + __ Ldr(temp, HeapOperand(temp, super_offset)); + // If heap poisoning is enabled, no need to unpoison + // `temp`, as we are comparing against null below. + __ Cbnz(temp, slow_path->GetEntryLabel()); + __ Bind(&do_put); + } else { + __ B(ne, slow_path->GetEntryLabel()); + } + temps.Release(temp2); } - temps.Release(temp2); } if (kPoisonHeapReferences) { @@ -1865,7 +2212,7 @@ void InstructionCodeGeneratorARM64::VisitArraySet(HArraySet* instruction) { } __ Str(source, destination); - if (!may_need_runtime_call) { + if (!may_need_runtime_call_for_type_check) { codegen_->MaybeRecordImplicitNullCheck(instruction); } } @@ -2532,40 +2879,44 @@ void InstructionCodeGeneratorARM64::VisitInstanceFieldSet(HInstanceFieldSet* ins void LocationsBuilderARM64::VisitInstanceOf(HInstanceOf* instruction) { LocationSummary::CallKind call_kind = LocationSummary::kNoCall; - switch (instruction->GetTypeCheckKind()) { + TypeCheckKind type_check_kind = instruction->GetTypeCheckKind(); + switch (type_check_kind) { case TypeCheckKind::kExactCheck: case TypeCheckKind::kAbstractClassCheck: case TypeCheckKind::kClassHierarchyCheck: case TypeCheckKind::kArrayObjectCheck: - call_kind = LocationSummary::kNoCall; + call_kind = + kEmitCompilerReadBarrier ? LocationSummary::kCallOnSlowPath : LocationSummary::kNoCall; break; + case TypeCheckKind::kArrayCheck: case TypeCheckKind::kUnresolvedCheck: case TypeCheckKind::kInterfaceCheck: - call_kind = LocationSummary::kCall; - break; - case TypeCheckKind::kArrayCheck: call_kind = LocationSummary::kCallOnSlowPath; break; } + LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary(instruction, call_kind); - if (call_kind != LocationSummary::kCall) { - locations->SetInAt(0, Location::RequiresRegister()); - locations->SetInAt(1, Location::RequiresRegister()); - // The out register is used as a temporary, so it overlaps with the inputs. - // Note that TypeCheckSlowPathARM64 uses this register too. - locations->SetOut(Location::RequiresRegister(), Location::kOutputOverlap); - } else { - InvokeRuntimeCallingConvention calling_convention; - locations->SetInAt(1, LocationFrom(calling_convention.GetRegisterAt(0))); - locations->SetInAt(0, LocationFrom(calling_convention.GetRegisterAt(1))); - locations->SetOut(calling_convention.GetReturnLocation(Primitive::kPrimInt)); + locations->SetInAt(0, Location::RequiresRegister()); + locations->SetInAt(1, Location::RequiresRegister()); + // The "out" register is used as a temporary, so it overlaps with the inputs. + // Note that TypeCheckSlowPathARM64 uses this register too. + locations->SetOut(Location::RequiresRegister(), Location::kOutputOverlap); + // When read barriers are enabled, we need a temporary register for + // some cases. + if (kEmitCompilerReadBarrier && + (type_check_kind == TypeCheckKind::kAbstractClassCheck || + type_check_kind == TypeCheckKind::kClassHierarchyCheck || + type_check_kind == TypeCheckKind::kArrayObjectCheck)) { + locations->AddTemp(Location::RequiresRegister()); } } void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { LocationSummary* locations = instruction->GetLocations(); + Location obj_loc = locations->InAt(0); Register obj = InputRegisterAt(instruction, 0); Register cls = InputRegisterAt(instruction, 1); + Location out_loc = locations->Out(); Register out = OutputRegister(instruction); uint32_t class_offset = mirror::Object::ClassOffset().Int32Value(); uint32_t super_offset = mirror::Class::SuperClassOffset().Int32Value(); @@ -2581,15 +2932,9 @@ void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { __ Cbz(obj, &zero); } - // In case of an interface/unresolved check, we put the object class into the object register. - // This is safe, as the register is caller-save, and the object must be in another - // register if it survives the runtime call. - Register target = (instruction->GetTypeCheckKind() == TypeCheckKind::kInterfaceCheck) || - (instruction->GetTypeCheckKind() == TypeCheckKind::kUnresolvedCheck) - ? obj - : out; - __ Ldr(target, HeapOperand(obj.W(), class_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(target); + // /* HeapReference<Class> */ out = obj->klass_ + __ Ldr(out, HeapOperand(obj.W(), class_offset)); + codegen_->MaybeGenerateReadBarrier(instruction, out_loc, out_loc, obj_loc, class_offset); switch (instruction->GetTypeCheckKind()) { case TypeCheckKind::kExactCheck: { @@ -2600,13 +2945,23 @@ void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { } break; } + case TypeCheckKind::kAbstractClassCheck: { // If the class is abstract, we eagerly fetch the super class of the // object to avoid doing a comparison we know will fail. vixl::Label loop, success; __ Bind(&loop); + Location temp_loc = kEmitCompilerReadBarrier ? locations->GetTemp(0) : Location::NoLocation(); + if (kEmitCompilerReadBarrier) { + // Save the value of `out` into `temp` before overwriting it + // in the following move operation, as we will need it for the + // read barrier below. + Register temp = WRegisterFrom(temp_loc); + __ Mov(temp, out); + } + // /* HeapReference<Class> */ out = out->super_class_ __ Ldr(out, HeapOperand(out, super_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(out); + codegen_->MaybeGenerateReadBarrier(instruction, out_loc, out_loc, temp_loc, super_offset); // If `out` is null, we use it for the result, and jump to `done`. __ Cbz(out, &done); __ Cmp(out, cls); @@ -2617,14 +2972,24 @@ void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { } break; } + case TypeCheckKind::kClassHierarchyCheck: { // Walk over the class hierarchy to find a match. vixl::Label loop, success; __ Bind(&loop); __ Cmp(out, cls); __ B(eq, &success); + Location temp_loc = kEmitCompilerReadBarrier ? locations->GetTemp(0) : Location::NoLocation(); + if (kEmitCompilerReadBarrier) { + // Save the value of `out` into `temp` before overwriting it + // in the following move operation, as we will need it for the + // read barrier below. + Register temp = WRegisterFrom(temp_loc); + __ Mov(temp, out); + } + // /* HeapReference<Class> */ out = out->super_class_ __ Ldr(out, HeapOperand(out, super_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(out); + codegen_->MaybeGenerateReadBarrier(instruction, out_loc, out_loc, temp_loc, super_offset); __ Cbnz(out, &loop); // If `out` is null, we use it for the result, and jump to `done`. __ B(&done); @@ -2635,14 +3000,24 @@ void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { } break; } + case TypeCheckKind::kArrayObjectCheck: { // Do an exact check. vixl::Label exact_check; __ Cmp(out, cls); __ B(eq, &exact_check); - // Otherwise, we need to check that the object's class is a non primitive array. + // Otherwise, we need to check that the object's class is a non-primitive array. + Location temp_loc = kEmitCompilerReadBarrier ? locations->GetTemp(0) : Location::NoLocation(); + if (kEmitCompilerReadBarrier) { + // Save the value of `out` into `temp` before overwriting it + // in the following move operation, as we will need it for the + // read barrier below. + Register temp = WRegisterFrom(temp_loc); + __ Mov(temp, out); + } + // /* HeapReference<Class> */ out = out->component_type_ __ Ldr(out, HeapOperand(out, component_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(out); + codegen_->MaybeGenerateReadBarrier(instruction, out_loc, out_loc, temp_loc, component_offset); // If `out` is null, we use it for the result, and jump to `done`. __ Cbz(out, &done); __ Ldrh(out, HeapOperand(out, primitive_offset)); @@ -2653,11 +3028,12 @@ void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { __ B(&done); break; } + case TypeCheckKind::kArrayCheck: { __ Cmp(out, cls); DCHECK(locations->OnlyCallsOnSlowPath()); - slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM64( - instruction, /* is_fatal */ false); + slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM64(instruction, + /* is_fatal */ false); codegen_->AddSlowPath(slow_path); __ B(ne, slow_path->GetEntryLabel()); __ Mov(out, 1); @@ -2666,13 +3042,25 @@ void InstructionCodeGeneratorARM64::VisitInstanceOf(HInstanceOf* instruction) { } break; } + case TypeCheckKind::kUnresolvedCheck: - case TypeCheckKind::kInterfaceCheck: - default: { - codegen_->InvokeRuntime(QUICK_ENTRY_POINT(pInstanceofNonTrivial), - instruction, - instruction->GetDexPc(), - nullptr); + case TypeCheckKind::kInterfaceCheck: { + // Note that we indeed only call on slow path, but we always go + // into the slow path for the unresolved and interface check + // cases. + // + // We cannot directly call the InstanceofNonTrivial runtime + // entry point without resorting to a type checking slow path + // here (i.e. by calling InvokeRuntime directly), as it would + // require to assign fixed registers for the inputs of this + // HInstanceOf instruction (following the runtime calling + // convention), which might be cluttered by the potential first + // read barrier emission at the beginning of this method. + DCHECK(locations->OnlyCallsOnSlowPath()); + slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM64(instruction, + /* is_fatal */ false); + codegen_->AddSlowPath(slow_path); + __ B(slow_path->GetEntryLabel()); if (zero.IsLinked()) { __ B(&done); } @@ -2698,58 +3086,62 @@ void LocationsBuilderARM64::VisitCheckCast(HCheckCast* instruction) { LocationSummary::CallKind call_kind = LocationSummary::kNoCall; bool throws_into_catch = instruction->CanThrowIntoCatchBlock(); - switch (instruction->GetTypeCheckKind()) { + TypeCheckKind type_check_kind = instruction->GetTypeCheckKind(); + switch (type_check_kind) { case TypeCheckKind::kExactCheck: case TypeCheckKind::kAbstractClassCheck: case TypeCheckKind::kClassHierarchyCheck: case TypeCheckKind::kArrayObjectCheck: - call_kind = throws_into_catch - ? LocationSummary::kCallOnSlowPath - : LocationSummary::kNoCall; + call_kind = (throws_into_catch || kEmitCompilerReadBarrier) ? + LocationSummary::kCallOnSlowPath : + LocationSummary::kNoCall; // In fact, call on a fatal (non-returning) slow path. break; + case TypeCheckKind::kArrayCheck: case TypeCheckKind::kUnresolvedCheck: case TypeCheckKind::kInterfaceCheck: - call_kind = LocationSummary::kCall; - break; - case TypeCheckKind::kArrayCheck: call_kind = LocationSummary::kCallOnSlowPath; break; } - LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary( - instruction, call_kind); - if (call_kind != LocationSummary::kCall) { - locations->SetInAt(0, Location::RequiresRegister()); - locations->SetInAt(1, Location::RequiresRegister()); - // Note that TypeCheckSlowPathARM64 uses this register too. - locations->AddTemp(Location::RequiresRegister()); - } else { - InvokeRuntimeCallingConvention calling_convention; - locations->SetInAt(1, LocationFrom(calling_convention.GetRegisterAt(0))); - locations->SetInAt(0, LocationFrom(calling_convention.GetRegisterAt(1))); + LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary(instruction, call_kind); + locations->SetInAt(0, Location::RequiresRegister()); + locations->SetInAt(1, Location::RequiresRegister()); + // Note that TypeCheckSlowPathARM64 uses this "temp" register too. + locations->AddTemp(Location::RequiresRegister()); + locations->AddTemp(Location::RequiresRegister()); + // When read barriers are enabled, we need an additional temporary + // register for some cases. + if (kEmitCompilerReadBarrier && + (type_check_kind == TypeCheckKind::kAbstractClassCheck || + type_check_kind == TypeCheckKind::kClassHierarchyCheck || + type_check_kind == TypeCheckKind::kArrayObjectCheck)) { + locations->AddTemp(Location::RequiresRegister()); } } void InstructionCodeGeneratorARM64::VisitCheckCast(HCheckCast* instruction) { LocationSummary* locations = instruction->GetLocations(); + Location obj_loc = locations->InAt(0); Register obj = InputRegisterAt(instruction, 0); Register cls = InputRegisterAt(instruction, 1); - Register temp; - if (!locations->WillCall()) { - temp = WRegisterFrom(instruction->GetLocations()->GetTemp(0)); - } - + Location temp_loc = locations->GetTemp(0); + Register temp = WRegisterFrom(temp_loc); uint32_t class_offset = mirror::Object::ClassOffset().Int32Value(); uint32_t super_offset = mirror::Class::SuperClassOffset().Int32Value(); uint32_t component_offset = mirror::Class::ComponentTypeOffset().Int32Value(); uint32_t primitive_offset = mirror::Class::PrimitiveTypeOffset().Int32Value(); - SlowPathCodeARM64* slow_path = nullptr; - if (!locations->WillCall()) { - slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM64( - instruction, !locations->CanCall()); - codegen_->AddSlowPath(slow_path); - } + TypeCheckKind type_check_kind = instruction->GetTypeCheckKind(); + bool is_type_check_slow_path_fatal = + (type_check_kind == TypeCheckKind::kExactCheck || + type_check_kind == TypeCheckKind::kAbstractClassCheck || + type_check_kind == TypeCheckKind::kClassHierarchyCheck || + type_check_kind == TypeCheckKind::kArrayObjectCheck) && + !instruction->CanThrowIntoCatchBlock(); + SlowPathCodeARM64* type_check_slow_path = + new (GetGraph()->GetArena()) TypeCheckSlowPathARM64(instruction, + is_type_check_slow_path_fatal); + codegen_->AddSlowPath(type_check_slow_path); vixl::Label done; // Avoid null check if we know obj is not null. @@ -2757,76 +3149,159 @@ void InstructionCodeGeneratorARM64::VisitCheckCast(HCheckCast* instruction) { __ Cbz(obj, &done); } - if (locations->WillCall()) { - __ Ldr(obj, HeapOperand(obj, class_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(obj); - } else { - __ Ldr(temp, HeapOperand(obj, class_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(temp); - } + // /* HeapReference<Class> */ temp = obj->klass_ + __ Ldr(temp, HeapOperand(obj, class_offset)); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, obj_loc, class_offset); - switch (instruction->GetTypeCheckKind()) { + switch (type_check_kind) { case TypeCheckKind::kExactCheck: case TypeCheckKind::kArrayCheck: { __ Cmp(temp, cls); // Jump to slow path for throwing the exception or doing a // more involved array check. - __ B(ne, slow_path->GetEntryLabel()); + __ B(ne, type_check_slow_path->GetEntryLabel()); break; } + case TypeCheckKind::kAbstractClassCheck: { // If the class is abstract, we eagerly fetch the super class of the // object to avoid doing a comparison we know will fail. - vixl::Label loop; + vixl::Label loop, compare_classes; __ Bind(&loop); + Location temp2_loc = + kEmitCompilerReadBarrier ? locations->GetTemp(1) : Location::NoLocation(); + if (kEmitCompilerReadBarrier) { + // Save the value of `temp` into `temp2` before overwriting it + // in the following move operation, as we will need it for the + // read barrier below. + Register temp2 = WRegisterFrom(temp2_loc); + __ Mov(temp2, temp); + } + // /* HeapReference<Class> */ temp = temp->super_class_ __ Ldr(temp, HeapOperand(temp, super_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(temp); - // Jump to the slow path to throw the exception. - __ Cbz(temp, slow_path->GetEntryLabel()); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, temp2_loc, super_offset); + + // If the class reference currently in `temp` is not null, jump + // to the `compare_classes` label to compare it with the checked + // class. + __ Cbnz(temp, &compare_classes); + // Otherwise, jump to the slow path to throw the exception. + // + // But before, move back the object's class into `temp` before + // going into the slow path, as it has been overwritten in the + // meantime. + // /* HeapReference<Class> */ temp = obj->klass_ + __ Ldr(temp, HeapOperand(obj, class_offset)); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, obj_loc, class_offset); + __ B(type_check_slow_path->GetEntryLabel()); + + __ Bind(&compare_classes); __ Cmp(temp, cls); __ B(ne, &loop); break; } + case TypeCheckKind::kClassHierarchyCheck: { // Walk over the class hierarchy to find a match. vixl::Label loop; __ Bind(&loop); __ Cmp(temp, cls); __ B(eq, &done); + + Location temp2_loc = + kEmitCompilerReadBarrier ? locations->GetTemp(1) : Location::NoLocation(); + if (kEmitCompilerReadBarrier) { + // Save the value of `temp` into `temp2` before overwriting it + // in the following move operation, as we will need it for the + // read barrier below. + Register temp2 = WRegisterFrom(temp2_loc); + __ Mov(temp2, temp); + } + // /* HeapReference<Class> */ temp = temp->super_class_ __ Ldr(temp, HeapOperand(temp, super_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(temp); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, temp2_loc, super_offset); + + // If the class reference currently in `temp` is not null, jump + // back at the beginning of the loop. __ Cbnz(temp, &loop); - // Jump to the slow path to throw the exception. - __ B(slow_path->GetEntryLabel()); + // Otherwise, jump to the slow path to throw the exception. + // + // But before, move back the object's class into `temp` before + // going into the slow path, as it has been overwritten in the + // meantime. + // /* HeapReference<Class> */ temp = obj->klass_ + __ Ldr(temp, HeapOperand(obj, class_offset)); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, obj_loc, class_offset); + __ B(type_check_slow_path->GetEntryLabel()); break; } + case TypeCheckKind::kArrayObjectCheck: { // Do an exact check. + vixl::Label check_non_primitive_component_type; __ Cmp(temp, cls); __ B(eq, &done); - // Otherwise, we need to check that the object's class is a non primitive array. + + // Otherwise, we need to check that the object's class is a non-primitive array. + Location temp2_loc = + kEmitCompilerReadBarrier ? locations->GetTemp(1) : Location::NoLocation(); + if (kEmitCompilerReadBarrier) { + // Save the value of `temp` into `temp2` before overwriting it + // in the following move operation, as we will need it for the + // read barrier below. + Register temp2 = WRegisterFrom(temp2_loc); + __ Mov(temp2, temp); + } + // /* HeapReference<Class> */ temp = temp->component_type_ __ Ldr(temp, HeapOperand(temp, component_offset)); - GetAssembler()->MaybeUnpoisonHeapReference(temp); - __ Cbz(temp, slow_path->GetEntryLabel()); + codegen_->MaybeGenerateReadBarrier( + instruction, temp_loc, temp_loc, temp2_loc, component_offset); + + // If the component type is not null (i.e. the object is indeed + // an array), jump to label `check_non_primitive_component_type` + // to further check that this component type is not a primitive + // type. + __ Cbnz(temp, &check_non_primitive_component_type); + // Otherwise, jump to the slow path to throw the exception. + // + // But before, move back the object's class into `temp` before + // going into the slow path, as it has been overwritten in the + // meantime. + // /* HeapReference<Class> */ temp = obj->klass_ + __ Ldr(temp, HeapOperand(obj, class_offset)); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, obj_loc, class_offset); + __ B(type_check_slow_path->GetEntryLabel()); + + __ Bind(&check_non_primitive_component_type); __ Ldrh(temp, HeapOperand(temp, primitive_offset)); static_assert(Primitive::kPrimNot == 0, "Expected 0 for kPrimNot"); - __ Cbnz(temp, slow_path->GetEntryLabel()); + __ Cbz(temp, &done); + // Same comment as above regarding `temp` and the slow path. + // /* HeapReference<Class> */ temp = obj->klass_ + __ Ldr(temp, HeapOperand(obj, class_offset)); + codegen_->MaybeGenerateReadBarrier(instruction, temp_loc, temp_loc, obj_loc, class_offset); + __ B(type_check_slow_path->GetEntryLabel()); break; } + case TypeCheckKind::kUnresolvedCheck: case TypeCheckKind::kInterfaceCheck: - default: - codegen_->InvokeRuntime(QUICK_ENTRY_POINT(pCheckCast), - instruction, - instruction->GetDexPc(), - nullptr); + // We always go into the type check slow path for the unresolved + // and interface check cases. + // + // We cannot directly call the CheckCast runtime entry point + // without resorting to a type checking slow path here (i.e. by + // calling InvokeRuntime directly), as it would require to + // assign fixed registers for the inputs of this HInstanceOf + // instruction (following the runtime calling convention), which + // might be cluttered by the potential first read barrier + // emission at the beginning of this method. + __ B(type_check_slow_path->GetEntryLabel()); break; } __ Bind(&done); - if (slow_path != nullptr) { - __ Bind(slow_path->GetExitLabel()); - } + __ Bind(type_check_slow_path->GetExitLabel()); } void LocationsBuilderARM64::VisitIntConstant(HIntConstant* constant) { @@ -2869,10 +3344,11 @@ void LocationsBuilderARM64::VisitInvokeInterface(HInvokeInterface* invoke) { void InstructionCodeGeneratorARM64::VisitInvokeInterface(HInvokeInterface* invoke) { // TODO: b/18116999, our IMTs can miss an IncompatibleClassChangeError. - Register temp = XRegisterFrom(invoke->GetLocations()->GetTemp(0)); + LocationSummary* locations = invoke->GetLocations(); + Register temp = XRegisterFrom(locations->GetTemp(0)); uint32_t method_offset = mirror::Class::EmbeddedImTableEntryOffset( invoke->GetImtIndex() % mirror::Class::kImtSize, kArm64PointerSize).Uint32Value(); - Location receiver = invoke->GetLocations()->InAt(0); + Location receiver = locations->InAt(0); Offset class_offset = mirror::Object::ClassOffset(); Offset entry_point = ArtMethod::EntryPointFromQuickCompiledCodeOffset(kArm64WordSize); @@ -2884,14 +3360,22 @@ void InstructionCodeGeneratorARM64::VisitInvokeInterface(HInvokeInterface* invok scratch_scope.Exclude(ip1); __ Mov(ip1, invoke->GetDexMethodIndex()); - // temp = object->GetClass(); if (receiver.IsStackSlot()) { __ Ldr(temp.W(), StackOperandFrom(receiver)); + // /* HeapReference<Class> */ temp = temp->klass_ __ Ldr(temp.W(), HeapOperand(temp.W(), class_offset)); } else { + // /* HeapReference<Class> */ temp = receiver->klass_ __ Ldr(temp.W(), HeapOperandFrom(receiver, class_offset)); } codegen_->MaybeRecordImplicitNullCheck(invoke); + // Instead of simply (possibly) unpoisoning `temp` here, we should + // emit a read barrier for the previous class reference load. + // However this is not required in practice, as this is an + // intermediate/temporary reference and because the current + // concurrent copying collector keeps the from-space memory + // intact/accessible until the end of the marking phase (the + // concurrent copying collector may not in the future). GetAssembler()->MaybeUnpoisonHeapReference(temp.W()); // temp = temp->GetImtEntryAt(method_offset); __ Ldr(temp, MemOperand(temp, method_offset)); @@ -3013,7 +3497,7 @@ void CodeGeneratorARM64::GenerateStaticOrDirectCall(HInvokeStaticOrDirect* invok __ Ldr(reg.X(), MemOperand(sp, kCurrentMethodStackOffset)); } - // temp = current_method->dex_cache_resolved_methods_; + // /* ArtMethod*[] */ temp = temp.ptr_sized_fields_->dex_cache_resolved_methods_; __ Ldr(reg.X(), MemOperand(method_reg.X(), ArtMethod::DexCacheResolvedMethodsOffset(kArm64WordSize).Int32Value())); @@ -3068,8 +3552,16 @@ void CodeGeneratorARM64::GenerateVirtualCall(HInvokeVirtual* invoke, Location te BlockPoolsScope block_pools(GetVIXLAssembler()); DCHECK(receiver.IsRegister()); + // /* HeapReference<Class> */ temp = receiver->klass_ __ Ldr(temp.W(), HeapOperandFrom(receiver, class_offset)); MaybeRecordImplicitNullCheck(invoke); + // Instead of simply (possibly) unpoisoning `temp` here, we should + // emit a read barrier for the previous class reference load. + // However this is not required in practice, as this is an + // intermediate/temporary reference and because the current + // concurrent copying collector keeps the from-space memory + // intact/accessible until the end of the marking phase (the + // concurrent copying collector may not in the future). GetAssembler()->MaybeUnpoisonHeapReference(temp.W()); // temp = temp->GetMethodAt(method_offset); __ Ldr(temp, MemOperand(temp, method_offset)); @@ -3182,7 +3674,8 @@ void LocationsBuilderARM64::VisitLoadClass(HLoadClass* cls) { CodeGenerator::CreateLoadClassLocationSummary( cls, LocationFrom(calling_convention.GetRegisterAt(0)), - LocationFrom(vixl::x0)); + LocationFrom(vixl::x0), + /* code_generator_supports_read_barrier */ true); } void InstructionCodeGeneratorARM64::VisitLoadClass(HLoadClass* cls) { @@ -3195,18 +3688,39 @@ void InstructionCodeGeneratorARM64::VisitLoadClass(HLoadClass* cls) { return; } + Location out_loc = cls->GetLocations()->Out(); Register out = OutputRegister(cls); Register current_method = InputRegisterAt(cls, 0); if (cls->IsReferrersClass()) { DCHECK(!cls->CanCallRuntime()); DCHECK(!cls->MustGenerateClinitCheck()); - __ Ldr(out, MemOperand(current_method, ArtMethod::DeclaringClassOffset().Int32Value())); + uint32_t declaring_class_offset = ArtMethod::DeclaringClassOffset().Int32Value(); + if (kEmitCompilerReadBarrier) { + // /* GcRoot<mirror::Class>* */ out = &(current_method->declaring_class_) + __ Add(out.X(), current_method.X(), declaring_class_offset); + // /* mirror::Class* */ out = out->Read() + codegen_->GenerateReadBarrierForRoot(cls, out_loc, out_loc); + } else { + // /* GcRoot<mirror::Class> */ out = current_method->declaring_class_ + __ Ldr(out, MemOperand(current_method, declaring_class_offset)); + } } else { DCHECK(cls->CanCallRuntime()); MemberOffset resolved_types_offset = ArtMethod::DexCacheResolvedTypesOffset(kArm64PointerSize); + // /* GcRoot<mirror::Class>[] */ out = + // current_method.ptr_sized_fields_->dex_cache_resolved_types_ __ Ldr(out.X(), MemOperand(current_method, resolved_types_offset.Int32Value())); - __ Ldr(out, MemOperand(out.X(), CodeGenerator::GetCacheOffset(cls->GetTypeIndex()))); - // TODO: We will need a read barrier here. + + size_t cache_offset = CodeGenerator::GetCacheOffset(cls->GetTypeIndex()); + if (kEmitCompilerReadBarrier) { + // /* GcRoot<mirror::Class>* */ out = &out[type_index] + __ Add(out.X(), out.X(), cache_offset); + // /* mirror::Class* */ out = out->Read() + codegen_->GenerateReadBarrierForRoot(cls, out_loc, out_loc); + } else { + // /* GcRoot<mirror::Class> */ out = out[type_index] + __ Ldr(out, MemOperand(out.X(), cache_offset)); + } SlowPathCodeARM64* slow_path = new (GetGraph()->GetArena()) LoadClassSlowPathARM64( cls, cls, cls->GetDexPc(), cls->MustGenerateClinitCheck()); @@ -3261,12 +3775,35 @@ void InstructionCodeGeneratorARM64::VisitLoadString(HLoadString* load) { SlowPathCodeARM64* slow_path = new (GetGraph()->GetArena()) LoadStringSlowPathARM64(load); codegen_->AddSlowPath(slow_path); + Location out_loc = load->GetLocations()->Out(); Register out = OutputRegister(load); Register current_method = InputRegisterAt(load, 0); - __ Ldr(out, MemOperand(current_method, ArtMethod::DeclaringClassOffset().Int32Value())); - __ Ldr(out.X(), HeapOperand(out, mirror::Class::DexCacheStringsOffset())); - __ Ldr(out, MemOperand(out.X(), CodeGenerator::GetCacheOffset(load->GetStringIndex()))); - // TODO: We will need a read barrier here. + + uint32_t declaring_class_offset = ArtMethod::DeclaringClassOffset().Int32Value(); + if (kEmitCompilerReadBarrier) { + // /* GcRoot<mirror::Class>* */ out = &(current_method->declaring_class_) + __ Add(out.X(), current_method.X(), declaring_class_offset); + // /* mirror::Class* */ out = out->Read() + codegen_->GenerateReadBarrierForRoot(load, out_loc, out_loc); + } else { + // /* GcRoot<mirror::Class> */ out = current_method->declaring_class_ + __ Ldr(out, MemOperand(current_method, declaring_class_offset)); + } + + // /* GcRoot<mirror::String>[] */ out = out->dex_cache_strings_ + __ Ldr(out.X(), HeapOperand(out, mirror::Class::DexCacheStringsOffset().Uint32Value())); + + size_t cache_offset = CodeGenerator::GetCacheOffset(load->GetStringIndex()); + if (kEmitCompilerReadBarrier) { + // /* GcRoot<mirror::String>* */ out = &out[string_index] + __ Add(out.X(), out.X(), cache_offset); + // /* mirror::String* */ out = out->Read() + codegen_->GenerateReadBarrierForRoot(load, out_loc, out_loc); + } else { + // /* GcRoot<mirror::String> */ out = out[string_index] + __ Ldr(out, MemOperand(out.X(), cache_offset)); + } + __ Cbz(out, slow_path->GetEntryLabel()); __ Bind(slow_path->GetExitLabel()); } @@ -3988,6 +4525,82 @@ void InstructionCodeGeneratorARM64::VisitPackedSwitch(HPackedSwitch* switch_inst } } +void CodeGeneratorARM64::GenerateReadBarrier(HInstruction* instruction, + Location out, + Location ref, + Location obj, + uint32_t offset, + Location index) { + DCHECK(kEmitCompilerReadBarrier); + + // If heap poisoning is enabled, the unpoisoning of the loaded + // reference will be carried out by the runtime within the slow + // path. + // + // Note that `ref` currently does not get unpoisoned (when heap + // poisoning is enabled), which is alright as the `ref` argument is + // not used by the artReadBarrierSlow entry point. + // + // TODO: Unpoison `ref` when it is used by artReadBarrierSlow. + SlowPathCodeARM64* slow_path = new (GetGraph()->GetArena()) + ReadBarrierForHeapReferenceSlowPathARM64(instruction, out, ref, obj, offset, index); + AddSlowPath(slow_path); + + // TODO: When read barrier has a fast path, add it here. + /* Currently the read barrier call is inserted after the original load. + * However, if we have a fast path, we need to perform the load of obj.LockWord *before* the + * original load. This load-load ordering is required by the read barrier. + * The fast path/slow path (for Baker's algorithm) should look like: + * + * bool isGray = obj.LockWord & kReadBarrierMask; + * lfence; // load fence or artificial data dependence to prevent load-load reordering + * ref = obj.field; // this is the original load + * if (isGray) { + * ref = Mark(ref); // ideally the slow path just does Mark(ref) + * } + */ + + __ B(slow_path->GetEntryLabel()); + __ Bind(slow_path->GetExitLabel()); +} + +void CodeGeneratorARM64::MaybeGenerateReadBarrier(HInstruction* instruction, + Location out, + Location ref, + Location obj, + uint32_t offset, + Location index) { + if (kEmitCompilerReadBarrier) { + // If heap poisoning is enabled, unpoisoning will be taken care of + // by the runtime within the slow path. + GenerateReadBarrier(instruction, out, ref, obj, offset, index); + } else if (kPoisonHeapReferences) { + GetAssembler()->UnpoisonHeapReference(WRegisterFrom(out)); + } +} + +void CodeGeneratorARM64::GenerateReadBarrierForRoot(HInstruction* instruction, + Location out, + Location root) { + DCHECK(kEmitCompilerReadBarrier); + + // Note that GC roots are not affected by heap poisoning, so we do + // not need to do anything special for this here. + SlowPathCodeARM64* slow_path = + new (GetGraph()->GetArena()) ReadBarrierForRootSlowPathARM64(instruction, out, root); + AddSlowPath(slow_path); + + // TODO: Implement a fast path for ReadBarrierForRoot, performing + // the following operation (for Baker's algorithm): + // + // if (thread.tls32_.is_gc_marking) { + // root = Mark(root); + // } + + __ B(slow_path->GetEntryLabel()); + __ Bind(slow_path->GetExitLabel()); +} + #undef __ #undef QUICK_ENTRY_POINT diff --git a/compiler/optimizing/code_generator_arm64.h b/compiler/optimizing/code_generator_arm64.h index 881afcc123..7950f078ad 100644 --- a/compiler/optimizing/code_generator_arm64.h +++ b/compiler/optimizing/code_generator_arm64.h @@ -424,6 +424,51 @@ class CodeGeneratorARM64 : public CodeGenerator { void EmitLinkerPatches(ArenaVector<LinkerPatch>* linker_patches) OVERRIDE; + // Generate a read barrier for a heap reference within `instruction`. + // + // A read barrier for an object reference read from the heap is + // implemented as a call to the artReadBarrierSlow runtime entry + // point, which is passed the values in locations `ref`, `obj`, and + // `offset`: + // + // mirror::Object* artReadBarrierSlow(mirror::Object* ref, + // mirror::Object* obj, + // uint32_t offset); + // + // The `out` location contains the value returned by + // artReadBarrierSlow. + // + // When `index` is provided (i.e. for array accesses), the offset + // value passed to artReadBarrierSlow is adjusted to take `index` + // into account. + void GenerateReadBarrier(HInstruction* instruction, + Location out, + Location ref, + Location obj, + uint32_t offset, + Location index = Location::NoLocation()); + + // If read barriers are enabled, generate a read barrier for a heap reference. + // If heap poisoning is enabled, also unpoison the reference in `out`. + void MaybeGenerateReadBarrier(HInstruction* instruction, + Location out, + Location ref, + Location obj, + uint32_t offset, + Location index = Location::NoLocation()); + + // Generate a read barrier for a GC root within `instruction`. + // + // A read barrier for an object reference GC root is implemented as + // a call to the artReadBarrierForRootSlow runtime entry point, + // which is passed the value in location `root`: + // + // mirror::Object* artReadBarrierForRootSlow(GcRoot<mirror::Object>* root); + // + // The `out` location contains the value returned by + // artReadBarrierForRootSlow. + void GenerateReadBarrierForRoot(HInstruction* instruction, Location out, Location root); + private: using Uint64ToLiteralMap = ArenaSafeMap<uint64_t, vixl::Literal<uint64_t>*>; using MethodToLiteralMap = ArenaSafeMap<MethodReference, diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc index 059abf090d..b04dcceb05 100644 --- a/compiler/optimizing/intrinsics_arm64.cc +++ b/compiler/optimizing/intrinsics_arm64.cc @@ -143,7 +143,23 @@ class IntrinsicSlowPathARM64 : public SlowPathCodeARM64 { bool IntrinsicLocationsBuilderARM64::TryDispatch(HInvoke* invoke) { Dispatch(invoke); LocationSummary* res = invoke->GetLocations(); - return res != nullptr && res->Intrinsified(); + if (res == nullptr) { + return false; + } + if (kEmitCompilerReadBarrier && res->CanCall()) { + // Generating an intrinsic for this HInvoke may produce an + // IntrinsicSlowPathARM64 slow path. Currently this approach + // does not work when using read barriers, as the emitted + // calling sequence will make use of another slow path + // (ReadBarrierForRootSlowPathARM64 for HInvokeStaticOrDirect, + // ReadBarrierSlowPathARM64 for HInvokeVirtual). So we bail + // out in this case. + // + // TODO: Find a way to have intrinsics work with read barriers. + invoke->SetLocations(nullptr); + return false; + } + return res->Intrinsified(); } #define __ masm-> @@ -818,9 +834,12 @@ static void GenUnsafeGet(HInvoke* invoke, (type == Primitive::kPrimLong) || (type == Primitive::kPrimNot)); vixl::MacroAssembler* masm = codegen->GetAssembler()->vixl_masm_; - Register base = WRegisterFrom(locations->InAt(1)); // Object pointer. - Register offset = XRegisterFrom(locations->InAt(2)); // Long offset. - Register trg = RegisterFrom(locations->Out(), type); + Location base_loc = locations->InAt(1); + Register base = WRegisterFrom(base_loc); // Object pointer. + Location offset_loc = locations->InAt(2); + Register offset = XRegisterFrom(offset_loc); // Long offset. + Location trg_loc = locations->Out(); + Register trg = RegisterFrom(trg_loc, type); bool use_acquire_release = codegen->GetInstructionSetFeatures().PreferAcquireRelease(); MemOperand mem_op(base.X(), offset); @@ -837,13 +856,18 @@ static void GenUnsafeGet(HInvoke* invoke, if (type == Primitive::kPrimNot) { DCHECK(trg.IsW()); - codegen->GetAssembler()->MaybeUnpoisonHeapReference(trg); + codegen->MaybeGenerateReadBarrier(invoke, trg_loc, trg_loc, base_loc, 0U, offset_loc); } } static void CreateIntIntIntToIntLocations(ArenaAllocator* arena, HInvoke* invoke) { + bool can_call = kEmitCompilerReadBarrier && + (invoke->GetIntrinsic() == Intrinsics::kUnsafeGetObject || + invoke->GetIntrinsic() == Intrinsics::kUnsafeGetObjectVolatile); LocationSummary* locations = new (arena) LocationSummary(invoke, - LocationSummary::kNoCall, + can_call ? + LocationSummary::kCallOnSlowPath : + LocationSummary::kNoCall, kIntrinsified); locations->SetInAt(0, Location::NoLocation()); // Unused receiver. locations->SetInAt(1, Location::RequiresRegister()); @@ -1057,6 +1081,9 @@ static void GenCas(LocationSummary* locations, Primitive::Type type, CodeGenerat if (use_acquire_release) { __ Bind(&loop_head); __ Ldaxr(tmp_value, MemOperand(tmp_ptr)); + // TODO: Do we need a read barrier here when `type == Primitive::kPrimNot`? + // Note that this code is not (yet) used when read barriers are + // enabled (see IntrinsicLocationsBuilderARM64::VisitUnsafeCASObject). __ Cmp(tmp_value, expected); __ B(&exit_loop, ne); __ Stlxr(tmp_32, value, MemOperand(tmp_ptr)); @@ -1065,6 +1092,9 @@ static void GenCas(LocationSummary* locations, Primitive::Type type, CodeGenerat __ Dmb(InnerShareable, BarrierWrites); __ Bind(&loop_head); __ Ldxr(tmp_value, MemOperand(tmp_ptr)); + // TODO: Do we need a read barrier here when `type == Primitive::kPrimNot`? + // Note that this code is not (yet) used when read barriers are + // enabled (see IntrinsicLocationsBuilderARM64::VisitUnsafeCASObject). __ Cmp(tmp_value, expected); __ B(&exit_loop, ne); __ Stxr(tmp_32, value, MemOperand(tmp_ptr)); @@ -1090,7 +1120,11 @@ void IntrinsicLocationsBuilderARM64::VisitUnsafeCASObject(HInvoke* invoke) { // The UnsafeCASObject intrinsic does not always work when heap // poisoning is enabled (it breaks run-test 004-UnsafeTest); turn it // off temporarily as a quick fix. + // // TODO(rpl): Fix it and turn it back on. + // + // TODO(rpl): Also, we should investigate whether we need a read + // barrier in the generated code. if (kPoisonHeapReferences) { return; } diff --git a/compiler/optimizing/optimizing_compiler.cc b/compiler/optimizing/optimizing_compiler.cc index dec08d8978..8440813a87 100644 --- a/compiler/optimizing/optimizing_compiler.cc +++ b/compiler/optimizing/optimizing_compiler.cc @@ -391,10 +391,11 @@ static bool IsInstructionSetSupported(InstructionSet instruction_set) { || instruction_set == kX86_64; } -// Read barrier are supported only on ARM, x86 and x86-64 at the moment. +// Read barrier are supported on ARM, ARM64, x86 and x86-64 at the moment. // TODO: Add support for other architectures and remove this function static bool InstructionSetSupportsReadBarrier(InstructionSet instruction_set) { - return instruction_set == kThumb2 + return instruction_set == kArm64 + || instruction_set == kThumb2 || instruction_set == kX86 || instruction_set == kX86_64; } |