Merge "ARM read barrier support for concurrent GC in Optimizing."
diff --git a/compiler/common_compiler_test.h b/compiler/common_compiler_test.h
index a121f8b..7b0e5af 100644
--- a/compiler/common_compiler_test.h
+++ b/compiler/common_compiler_test.h
@@ -128,6 +128,7 @@
#define TEST_DISABLED_FOR_READ_BARRIER_WITH_OPTIMIZING_FOR_UNSUPPORTED_INSTRUCTION_SETS() \
if (kUseReadBarrier && GetCompilerKind() == Compiler::kOptimizing) { \
switch (GetInstructionSet()) { \
+ case kThumb2: \
case kX86: \
case kX86_64: \
/* Instruction set has read barrier support. */ \
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 655bbb8..12ab68e 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -34,6 +34,9 @@
namespace art {
+template<class MirrorType>
+class GcRoot;
+
namespace arm {
static bool ExpectedPairLayout(Location location) {
@@ -286,15 +289,6 @@
CodeGeneratorARM* arm_codegen = down_cast<CodeGeneratorARM*>(codegen);
__ Bind(GetEntryLabel());
- if (instruction_->IsCheckCast()) {
- // The codegen for the instruction overwrites `temp`, so put it back in place.
- Register obj = locations->InAt(0).AsRegister<Register>();
- Register temp = locations->GetTemp(0).AsRegister<Register>();
- uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
- __ LoadFromOffset(kLoadWord, temp, obj, class_offset);
- __ MaybeUnpoisonHeapReference(temp);
- }
-
if (!is_fatal_) {
SaveLiveRegisters(codegen, locations);
}
@@ -315,6 +309,8 @@
instruction_,
instruction_->GetDexPc(),
this);
+ CheckEntrypointTypes<
+ kQuickInstanceofNonTrivial, uint32_t, const mirror::Class*, const mirror::Class*>();
arm_codegen->Move32(locations->Out(), Location::RegisterLocation(R0));
} else {
DCHECK(instruction_->IsCheckCast());
@@ -322,6 +318,7 @@
instruction_,
instruction_->GetDexPc(),
this);
+ CheckEntrypointTypes<kQuickCheckCast, void, const mirror::Class*, const mirror::Class*>();
}
if (!is_fatal_) {
@@ -408,6 +405,221 @@
DISALLOW_COPY_AND_ASSIGN(ArraySetSlowPathARM);
};
+// Slow path generating a read barrier for a heap reference.
+class ReadBarrierForHeapReferenceSlowPathARM : public SlowPathCode {
+ public:
+ ReadBarrierForHeapReferenceSlowPathARM(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.:
+ //
+ // __ LoadFromOffset(kLoadWord, out, out, 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 {
+ CodeGeneratorARM* arm_codegen = down_cast<CodeGeneratorARM*>(codegen);
+ LocationSummary* locations = instruction_->GetLocations();
+ Register reg_out = out_.AsRegister<Register>();
+ DCHECK(locations->CanCall());
+ DCHECK(!locations->GetLiveRegisters()->ContainsCoreRegister(reg_out));
+ DCHECK(!instruction_->IsInvoke() ||
+ (instruction_->IsInvokeStaticOrDirect() &&
+ instruction_->GetLocations()->Intrinsified()));
+
+ __ Bind(GetEntryLabel());
+ 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 = index_.AsRegister<Register>();
+ 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 art::arm::Thumb2Assembler::Lsl and
+ // art::arm::Thumb2Assembler::AddConstant 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, index_reg);
+ index_reg = free_reg;
+ index = Location::RegisterLocation(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, TIMES_4);
+ static_assert(
+ sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t),
+ "art::mirror::HeapReference<art::mirror::Object> and int32_t have different sizes.");
+ __ AddConstant(index_reg, index_reg, 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_,
+ Location::RegisterLocation(calling_convention.GetRegisterAt(0)),
+ Primitive::kPrimNot,
+ nullptr);
+ parallel_move.AddMove(obj_,
+ Location::RegisterLocation(calling_convention.GetRegisterAt(1)),
+ Primitive::kPrimNot,
+ nullptr);
+ if (index.IsValid()) {
+ parallel_move.AddMove(index,
+ Location::RegisterLocation(calling_convention.GetRegisterAt(2)),
+ Primitive::kPrimInt,
+ nullptr);
+ codegen->GetMoveResolver()->EmitNativeCode(¶llel_move);
+ } else {
+ codegen->GetMoveResolver()->EmitNativeCode(¶llel_move);
+ __ LoadImmediate(calling_convention.GetRegisterAt(2), offset_);
+ }
+ arm_codegen->InvokeRuntime(QUICK_ENTRY_POINT(pReadBarrierSlow),
+ instruction_,
+ instruction_->GetDexPc(),
+ this);
+ CheckEntrypointTypes<
+ kQuickReadBarrierSlow, mirror::Object*, mirror::Object*, mirror::Object*, uint32_t>();
+ arm_codegen->Move32(out_, Location::RegisterLocation(R0));
+
+ RestoreLiveRegisters(codegen, locations);
+ __ b(GetExitLabel());
+ }
+
+ const char* GetDescription() const OVERRIDE { return "ReadBarrierForHeapReferenceSlowPathARM"; }
+
+ private:
+ Register FindAvailableCallerSaveRegister(CodeGenerator* codegen) {
+ size_t ref = static_cast<int>(ref_.AsRegister<Register>());
+ size_t obj = static_cast<int>(obj_.AsRegister<Register>());
+ for (size_t i = 0, e = codegen->GetNumberOfCoreRegisters(); i < e; ++i) {
+ if (i != ref && i != obj && !codegen->IsCoreCalleeSaveRegister(i)) {
+ return static_cast<Register>(i);
+ }
+ }
+ // We shall never fail to find a free caller-save register, as
+ // there are more than two core caller-save registers on ARM
+ // (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 caller-save 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(ReadBarrierForHeapReferenceSlowPathARM);
+};
+
+// Slow path generating a read barrier for a GC root.
+class ReadBarrierForRootSlowPathARM : public SlowPathCode {
+ public:
+ ReadBarrierForRootSlowPathARM(HInstruction* instruction, Location out, Location root)
+ : instruction_(instruction), out_(out), root_(root) {}
+
+ void EmitNativeCode(CodeGenerator* codegen) OVERRIDE {
+ LocationSummary* locations = instruction_->GetLocations();
+ Register reg_out = out_.AsRegister<Register>();
+ DCHECK(locations->CanCall());
+ DCHECK(!locations->GetLiveRegisters()->ContainsCoreRegister(reg_out));
+ DCHECK(instruction_->IsLoadClass() || instruction_->IsLoadString());
+
+ __ Bind(GetEntryLabel());
+ SaveLiveRegisters(codegen, locations);
+
+ InvokeRuntimeCallingConvention calling_convention;
+ CodeGeneratorARM* arm_codegen = down_cast<CodeGeneratorARM*>(codegen);
+ arm_codegen->Move32(Location::RegisterLocation(calling_convention.GetRegisterAt(0)), root_);
+ arm_codegen->InvokeRuntime(QUICK_ENTRY_POINT(pReadBarrierForRootSlow),
+ instruction_,
+ instruction_->GetDexPc(),
+ this);
+ CheckEntrypointTypes<kQuickReadBarrierForRootSlow, mirror::Object*, GcRoot<mirror::Object>*>();
+ arm_codegen->Move32(out_, Location::RegisterLocation(R0));
+
+ RestoreLiveRegisters(codegen, locations);
+ __ b(GetExitLabel());
+ }
+
+ const char* GetDescription() const OVERRIDE { return "ReadBarrierForRootSlowPathARM"; }
+
+ private:
+ HInstruction* const instruction_;
+ const Location out_;
+ const Location root_;
+
+ DISALLOW_COPY_AND_ASSIGN(ReadBarrierForRootSlowPathARM);
+};
+
#undef __
#define __ down_cast<ArmAssembler*>(GetAssembler())->
@@ -581,7 +793,7 @@
LOG(FATAL) << "Unreachable type " << type;
}
- return Location();
+ return Location::NoLocation();
}
void CodeGeneratorARM::SetupBlockedRegisters(bool is_baseline) const {
@@ -820,7 +1032,7 @@
LOG(FATAL) << "Unexpected parameter type " << type;
break;
}
- return Location();
+ return Location::NoLocation();
}
Location InvokeDexCallingConventionVisitorARM::GetReturnLocation(Primitive::Type type) const {
@@ -847,7 +1059,7 @@
}
case Primitive::kPrimVoid:
- return Location();
+ return Location::NoLocation();
}
UNREACHABLE();
@@ -1762,29 +1974,39 @@
void InstructionCodeGeneratorARM::VisitInvokeInterface(HInvokeInterface* invoke) {
// TODO: b/18116999, our IMTs can miss an IncompatibleClassChangeError.
- Register temp = invoke->GetLocations()->GetTemp(0).AsRegister<Register>();
+ LocationSummary* locations = invoke->GetLocations();
+ Register temp = locations->GetTemp(0).AsRegister<Register>();
+ Register hidden_reg = locations->GetTemp(1).AsRegister<Register>();
uint32_t method_offset = mirror::Class::EmbeddedImTableEntryOffset(
invoke->GetImtIndex() % mirror::Class::kImtSize, kArmPointerSize).Uint32Value();
- LocationSummary* locations = invoke->GetLocations();
Location receiver = locations->InAt(0);
uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
- // Set the hidden argument.
- __ LoadImmediate(invoke->GetLocations()->GetTemp(1).AsRegister<Register>(),
- invoke->GetDexMethodIndex());
+ // Set the hidden argument. This is safe to do this here, as R12
+ // won't be modified thereafter, before the `blx` (call) instruction.
+ DCHECK_EQ(R12, hidden_reg);
+ __ LoadImmediate(hidden_reg, invoke->GetDexMethodIndex());
- // temp = object->GetClass();
if (receiver.IsStackSlot()) {
__ LoadFromOffset(kLoadWord, temp, SP, receiver.GetStackIndex());
+ // /* HeapReference<Class> */ temp = temp->klass_
__ LoadFromOffset(kLoadWord, temp, temp, class_offset);
} else {
+ // /* HeapReference<Class> */ temp = receiver->klass_
__ LoadFromOffset(kLoadWord, temp, receiver.AsRegister<Register>(), 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).
__ MaybeUnpoisonHeapReference(temp);
// temp = temp->GetImtEntryAt(method_offset);
- uint32_t entry_point = ArtMethod::EntryPointFromQuickCompiledCodeOffset(
- kArmWordSize).Int32Value();
+ uint32_t entry_point =
+ ArtMethod::EntryPointFromQuickCompiledCodeOffset(kArmWordSize).Int32Value();
__ LoadFromOffset(kLoadWord, temp, temp, method_offset);
// LR = temp->GetEntryPoint();
__ LoadFromOffset(kLoadWord, LR, temp, entry_point);
@@ -3407,6 +3629,9 @@
Register out_lo,
Register out_hi) {
if (offset != 0) {
+ // Ensure `out_lo` is different from `addr`, so that loading
+ // `offset` into `out_lo` does not clutter `addr`.
+ DCHECK_NE(out_lo, addr);
__ LoadImmediate(out_lo, offset);
__ add(IP, addr, ShifterOperand(out_lo));
addr = IP;
@@ -3594,14 +3819,26 @@
void LocationsBuilderARM::HandleFieldGet(HInstruction* instruction, const FieldInfo& field_info) {
DCHECK(instruction->IsInstanceFieldGet() || instruction->IsStaticFieldGet());
+
+ bool object_field_get_with_read_barrier =
+ kEmitCompilerReadBarrier && (field_info.GetFieldType() == 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());
bool volatile_for_double = field_info.IsVolatile()
&& (field_info.GetFieldType() == Primitive::kPrimDouble)
&& !codegen_->GetInstructionSetFeatures().HasAtomicLdrdAndStrd();
- bool overlap = field_info.IsVolatile() && (field_info.GetFieldType() == Primitive::kPrimLong);
+ // The output overlaps in case of volatile long: we don't want the
+ // code generated by GenerateWideAtomicLoad to overwrite the
+ // object's location. Likewise, in the case of an object field get
+ // with read barriers enabled, we do not want the load to overwrite
+ // the object's location, as we need it to emit the read barrier.
+ bool overlap = (field_info.IsVolatile() && (field_info.GetFieldType() == Primitive::kPrimLong)) ||
+ object_field_get_with_read_barrier;
if (Primitive::IsFloatingPointType(instruction->GetType())) {
locations->SetOut(Location::RequiresFpuRegister());
@@ -3667,7 +3904,8 @@
DCHECK(instruction->IsInstanceFieldGet() || instruction->IsStaticFieldGet());
LocationSummary* locations = instruction->GetLocations();
- Register base = locations->InAt(0).AsRegister<Register>();
+ Location base_loc = locations->InAt(0);
+ Register base = base_loc.AsRegister<Register>();
Location out = locations->Out();
bool is_volatile = field_info.IsVolatile();
bool atomic_ldrd_strd = codegen_->GetInstructionSetFeatures().HasAtomicLdrdAndStrd();
@@ -3747,7 +3985,7 @@
}
if (field_type == Primitive::kPrimNot) {
- __ MaybeUnpoisonHeapReference(out.AsRegister<Register>());
+ codegen_->MaybeGenerateReadBarrier(instruction, out, out, base_loc, offset);
}
}
@@ -3891,20 +4129,31 @@
}
void LocationsBuilderARM::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 InstructionCodeGeneratorARM::VisitArrayGet(HArrayGet* instruction) {
LocationSummary* locations = instruction->GetLocations();
- Register obj = locations->InAt(0).AsRegister<Register>();
+ Location obj_loc = locations->InAt(0);
+ Register obj = obj_loc.AsRegister<Register>();
Location index = locations->InAt(1);
Primitive::Type type = instruction->GetType();
@@ -3967,8 +4216,9 @@
case Primitive::kPrimInt:
case Primitive::kPrimNot: {
- static_assert(sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t),
- "art::mirror::HeapReference<mirror::Object> and int32_t have different sizes.");
+ static_assert(
+ sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t),
+ "art::mirror::HeapReference<mirror::Object> and int32_t have different sizes.");
uint32_t data_offset = mirror::Array::DataOffset(sizeof(int32_t)).Uint32Value();
Register out = locations->Out().AsRegister<Register>();
if (index.IsConstant()) {
@@ -4031,8 +4281,17 @@
codegen_->MaybeRecordImplicitNullCheck(instruction);
if (type == Primitive::kPrimNot) {
- Register out = locations->Out().AsRegister<Register>();
- __ MaybeUnpoisonHeapReference(out);
+ static_assert(
+ sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t),
+ "art::mirror::HeapReference<art::mirror::Object> and int32_t have different sizes.");
+ uint32_t data_offset = mirror::Array::DataOffset(sizeof(int32_t)).Uint32Value();
+ Location out = locations->Out();
+ if (index.IsConstant()) {
+ uint32_t offset = (index.GetConstant()->AsIntConstant()->GetValue() << TIMES_4) + data_offset;
+ codegen_->MaybeGenerateReadBarrier(instruction, out, out, obj_loc, offset);
+ } else {
+ codegen_->MaybeGenerateReadBarrier(instruction, out, out, obj_loc, data_offset, index);
+ }
}
}
@@ -4041,11 +4300,16 @@
bool needs_write_barrier =
CodeGenerator::StoreNeedsWriteBarrier(value_type, instruction->GetValue());
- bool may_need_runtime_call = instruction->NeedsTypeCheck();
+ 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,
- may_need_runtime_call ? 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(value_type)) {
@@ -4053,20 +4317,20 @@
} else {
locations->SetInAt(2, Location::RequiresRegister());
}
-
if (needs_write_barrier) {
// Temporary registers for the write barrier.
locations->AddTemp(Location::RequiresRegister()); // Possibly used for ref. poisoning too.
- locations->AddTemp(Location::RequiresRegister());
+ locations->AddTemp(Location::RequiresRegister()); // Possibly used for read barrier too.
}
}
void InstructionCodeGeneratorARM::VisitArraySet(HArraySet* instruction) {
LocationSummary* locations = instruction->GetLocations();
- Register array = locations->InAt(0).AsRegister<Register>();
+ Location array_loc = locations->InAt(0);
+ Register array = array_loc.AsRegister<Register>();
Location index = locations->InAt(1);
Primitive::Type value_type = instruction->GetComponentType();
- 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());
@@ -4103,7 +4367,8 @@
case Primitive::kPrimNot: {
uint32_t data_offset = mirror::Array::DataOffset(sizeof(int32_t)).Uint32Value();
- Register value = locations->InAt(2).AsRegister<Register>();
+ Location value_loc = locations->InAt(2);
+ Register value = value_loc.AsRegister<Register>();
Register source = value;
if (instruction->InputAt(2)->IsNullConstant()) {
@@ -4117,6 +4382,8 @@
__ add(IP, array, ShifterOperand(index.AsRegister<Register>(), LSL, TIMES_4));
__ StoreToOffset(kStoreWord, source, IP, data_offset);
}
+ DCHECK(!needs_write_barrier);
+ DCHECK(!may_need_runtime_call_for_type_check);
break;
}
@@ -4129,7 +4396,7 @@
Label done;
SlowPathCode* slow_path = nullptr;
- if (may_need_runtime_call) {
+ if (may_need_runtime_call_for_type_check) {
slow_path = new (GetGraph()->GetArena()) ArraySetSlowPathARM(instruction);
codegen_->AddSlowPath(slow_path);
if (instruction->GetValueCanBeNull()) {
@@ -4149,23 +4416,63 @@
__ Bind(&non_zero);
}
- __ LoadFromOffset(kLoadWord, temp1, array, class_offset);
- codegen_->MaybeRecordImplicitNullCheck(instruction);
- __ MaybeUnpoisonHeapReference(temp1);
- __ LoadFromOffset(kLoadWord, temp1, temp1, component_offset);
- __ LoadFromOffset(kLoadWord, temp2, value, class_offset);
- // No need to poison/unpoison, we're comparing two poisoined references.
- __ cmp(temp1, ShifterOperand(temp2));
- if (instruction->StaticTypeOfArrayIsObjectArray()) {
- Label do_put;
- __ b(&do_put, EQ);
- __ MaybeUnpoisonHeapReference(temp1);
- __ LoadFromOffset(kLoadWord, temp1, temp1, super_offset);
- // No need to poison/unpoison, we're comparing against null.
- __ CompareAndBranchIfNonZero(temp1, slow_path->GetEntryLabel());
- __ Bind(&do_put);
+ if (kEmitCompilerReadBarrier) {
+ // When read barriers are enabled, the type checking
+ // instrumentation requires two read barriers:
+ //
+ // __ Mov(temp2, temp1);
+ // // /* HeapReference<Class> */ temp1 = temp1->component_type_
+ // __ LoadFromOffset(kLoadWord, temp1, temp1, component_offset);
+ // codegen_->GenerateReadBarrier(
+ // instruction, temp1_loc, temp1_loc, temp2_loc, component_offset);
+ //
+ // // /* HeapReference<Class> */ temp2 = value->klass_
+ // __ LoadFromOffset(kLoadWord, temp2, value, class_offset);
+ // codegen_->GenerateReadBarrier(
+ // instruction, temp2_loc, temp2_loc, value_loc, class_offset, temp1_loc);
+ //
+ // __ cmp(temp1, ShifterOperand(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(slow_path->GetEntryLabel(), NE);
+ // /* HeapReference<Class> */ temp1 = array->klass_
+ __ LoadFromOffset(kLoadWord, temp1, array, class_offset);
+ codegen_->MaybeRecordImplicitNullCheck(instruction);
+ __ MaybeUnpoisonHeapReference(temp1);
+
+ // /* HeapReference<Class> */ temp1 = temp1->component_type_
+ __ LoadFromOffset(kLoadWord, temp1, temp1, component_offset);
+ // /* HeapReference<Class> */ temp2 = value->klass_
+ __ LoadFromOffset(kLoadWord, temp2, value, class_offset);
+ // If heap poisoning is enabled, no need to unpoison `temp1`
+ // nor `temp2`, as we are comparing two poisoned references.
+ __ cmp(temp1, ShifterOperand(temp2));
+
+ if (instruction->StaticTypeOfArrayIsObjectArray()) {
+ Label do_put;
+ __ b(&do_put, EQ);
+ // If heap poisoning is enabled, the `temp1` reference has
+ // not been unpoisoned yet; unpoison it now.
+ __ MaybeUnpoisonHeapReference(temp1);
+
+ // /* HeapReference<Class> */ temp1 = temp1->super_class_
+ __ LoadFromOffset(kLoadWord, temp1, temp1, super_offset);
+ // If heap poisoning is enabled, no need to unpoison
+ // `temp1`, as we are comparing against null below.
+ __ CompareAndBranchIfNonZero(temp1, slow_path->GetEntryLabel());
+ __ Bind(&do_put);
+ } else {
+ __ b(slow_path->GetEntryLabel(), NE);
+ }
}
}
@@ -4189,7 +4496,7 @@
__ StoreToOffset(kStoreWord, source, IP, data_offset);
}
- if (!may_need_runtime_call) {
+ if (!may_need_runtime_call_for_type_check) {
codegen_->MaybeRecordImplicitNullCheck(instruction);
}
@@ -4618,7 +4925,8 @@
CodeGenerator::CreateLoadClassLocationSummary(
cls,
Location::RegisterLocation(calling_convention.GetRegisterAt(0)),
- Location::RegisterLocation(R0));
+ Location::RegisterLocation(R0),
+ /* code_generator_supports_read_barrier */ true);
}
void InstructionCodeGeneratorARM::VisitLoadClass(HLoadClass* cls) {
@@ -4632,21 +4940,42 @@
return;
}
- Register out = locations->Out().AsRegister<Register>();
+ Location out_loc = locations->Out();
+ Register out = out_loc.AsRegister<Register>();
Register current_method = locations->InAt(0).AsRegister<Register>();
+
if (cls->IsReferrersClass()) {
DCHECK(!cls->CanCallRuntime());
DCHECK(!cls->MustGenerateClinitCheck());
- __ LoadFromOffset(
- kLoadWord, out, current_method, ArtMethod::DeclaringClassOffset().Int32Value());
+ uint32_t declaring_class_offset = ArtMethod::DeclaringClassOffset().Int32Value();
+ if (kEmitCompilerReadBarrier) {
+ // /* GcRoot<mirror::Class>* */ out = &(current_method->declaring_class_)
+ __ AddConstant(out, current_method, declaring_class_offset);
+ // /* mirror::Class* */ out = out->Read()
+ codegen_->GenerateReadBarrierForRoot(cls, out_loc, out_loc);
+ } else {
+ // /* GcRoot<mirror::Class> */ out = current_method->declaring_class_
+ __ LoadFromOffset(kLoadWord, out, current_method, declaring_class_offset);
+ }
} else {
DCHECK(cls->CanCallRuntime());
+ // /* GcRoot<mirror::Class>[] */ out =
+ // current_method.ptr_sized_fields_->dex_cache_resolved_types_
__ LoadFromOffset(kLoadWord,
out,
current_method,
ArtMethod::DexCacheResolvedTypesOffset(kArmPointerSize).Int32Value());
- __ LoadFromOffset(kLoadWord, out, out, 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]
+ __ AddConstant(out, out, cache_offset);
+ // /* mirror::Class* */ out = out->Read()
+ codegen_->GenerateReadBarrierForRoot(cls, out_loc, out_loc);
+ } else {
+ // /* GcRoot<mirror::Class> */ out = out[type_index]
+ __ LoadFromOffset(kLoadWord, out, out, cache_offset);
+ }
SlowPathCode* slow_path = new (GetGraph()->GetArena()) LoadClassSlowPathARM(
cls, cls, cls->GetDexPc(), cls->MustGenerateClinitCheck());
@@ -4701,13 +5030,35 @@
codegen_->AddSlowPath(slow_path);
LocationSummary* locations = load->GetLocations();
- Register out = locations->Out().AsRegister<Register>();
+ Location out_loc = locations->Out();
+ Register out = out_loc.AsRegister<Register>();
Register current_method = locations->InAt(0).AsRegister<Register>();
- __ LoadFromOffset(
- kLoadWord, out, current_method, ArtMethod::DeclaringClassOffset().Int32Value());
+
+ uint32_t declaring_class_offset = ArtMethod::DeclaringClassOffset().Int32Value();
+ if (kEmitCompilerReadBarrier) {
+ // /* GcRoot<mirror::Class>* */ out = &(current_method->declaring_class_)
+ __ AddConstant(out, current_method, declaring_class_offset);
+ // /* mirror::Class* */ out = out->Read()
+ codegen_->GenerateReadBarrierForRoot(load, out_loc, out_loc);
+ } else {
+ // /* GcRoot<mirror::Class> */ out = current_method->declaring_class_
+ __ LoadFromOffset(kLoadWord, out, current_method, declaring_class_offset);
+ }
+
+ // /* GcRoot<mirror::String>[] */ out = out->dex_cache_strings_
__ LoadFromOffset(kLoadWord, out, out, mirror::Class::DexCacheStringsOffset().Int32Value());
- __ LoadFromOffset(kLoadWord, out, out, CodeGenerator::GetCacheOffset(load->GetStringIndex()));
- // TODO: We will need a read barrier here.
+
+ size_t cache_offset = CodeGenerator::GetCacheOffset(load->GetStringIndex());
+ if (kEmitCompilerReadBarrier) {
+ // /* GcRoot<mirror::String>* */ out = &out[string_index]
+ __ AddConstant(out, out, cache_offset);
+ // /* mirror::String* */ out = out->Read()
+ codegen_->GenerateReadBarrierForRoot(load, out_loc, out_loc);
+ } else {
+ // /* GcRoot<mirror::String> */ out = out[string_index]
+ __ LoadFromOffset(kLoadWord, out, out, cache_offset);
+ }
+
__ CompareAndBranchIfZero(out, slow_path->GetEntryLabel());
__ Bind(slow_path->GetExitLabel());
}
@@ -4750,41 +5101,45 @@
void LocationsBuilderARM::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;
- break;
- case TypeCheckKind::kUnresolvedCheck:
- case TypeCheckKind::kInterfaceCheck:
- call_kind = LocationSummary::kCall;
+ call_kind =
+ kEmitCompilerReadBarrier ? LocationSummary::kCallOnSlowPath : LocationSummary::kNoCall;
break;
case TypeCheckKind::kArrayCheck:
+ case TypeCheckKind::kUnresolvedCheck:
+ case TypeCheckKind::kInterfaceCheck:
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 TypeCheckSlowPathARM uses this register too.
- locations->SetOut(Location::RequiresRegister(), Location::kOutputOverlap);
- } else {
- InvokeRuntimeCallingConvention calling_convention;
- locations->SetInAt(1, Location::RegisterLocation(calling_convention.GetRegisterAt(0)));
- locations->SetInAt(0, Location::RegisterLocation(calling_convention.GetRegisterAt(1)));
- locations->SetOut(Location::RegisterLocation(R0));
+ 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 TypeCheckSlowPathARM 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 InstructionCodeGeneratorARM::VisitInstanceOf(HInstanceOf* instruction) {
LocationSummary* locations = instruction->GetLocations();
- Register obj = locations->InAt(0).AsRegister<Register>();
+ Location obj_loc = locations->InAt(0);
+ Register obj = obj_loc.AsRegister<Register>();
Register cls = locations->InAt(1).AsRegister<Register>();
- Register out = locations->Out().AsRegister<Register>();
+ Location out_loc = locations->Out();
+ Register out = out_loc.AsRegister<Register>();
uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
uint32_t super_offset = mirror::Class::SuperClassOffset().Int32Value();
uint32_t component_offset = mirror::Class::ComponentTypeOffset().Int32Value();
@@ -4798,15 +5153,9 @@
__ CompareAndBranchIfZero(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;
- __ LoadFromOffset(kLoadWord, target, obj, class_offset);
- __ MaybeUnpoisonHeapReference(target);
+ // /* HeapReference<Class> */ out = obj->klass_
+ __ LoadFromOffset(kLoadWord, out, obj, class_offset);
+ codegen_->MaybeGenerateReadBarrier(instruction, out_loc, out_loc, obj_loc, class_offset);
switch (instruction->GetTypeCheckKind()) {
case TypeCheckKind::kExactCheck: {
@@ -4817,13 +5166,23 @@
__ b(&done);
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.
Label loop;
__ 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 = temp_loc.AsRegister<Register>();
+ __ Mov(temp, out);
+ }
+ // /* HeapReference<Class> */ out = out->super_class_
__ LoadFromOffset(kLoadWord, out, out, super_offset);
- __ 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`.
__ CompareAndBranchIfZero(out, &done);
__ cmp(out, ShifterOperand(cls));
@@ -4834,14 +5193,24 @@
}
break;
}
+
case TypeCheckKind::kClassHierarchyCheck: {
// Walk over the class hierarchy to find a match.
Label loop, success;
__ Bind(&loop);
__ cmp(out, ShifterOperand(cls));
__ b(&success, EQ);
+ 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 = temp_loc.AsRegister<Register>();
+ __ Mov(temp, out);
+ }
+ // /* HeapReference<Class> */ out = out->super_class_
__ LoadFromOffset(kLoadWord, out, out, super_offset);
- __ MaybeUnpoisonHeapReference(out);
+ codegen_->MaybeGenerateReadBarrier(instruction, out_loc, out_loc, temp_loc, super_offset);
__ CompareAndBranchIfNonZero(out, &loop);
// If `out` is null, we use it for the result, and jump to `done`.
__ b(&done);
@@ -4852,14 +5221,24 @@
}
break;
}
+
case TypeCheckKind::kArrayObjectCheck: {
// Do an exact check.
Label exact_check;
__ cmp(out, ShifterOperand(cls));
__ b(&exact_check, EQ);
- // 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 = temp_loc.AsRegister<Register>();
+ __ Mov(temp, out);
+ }
+ // /* HeapReference<Class> */ out = out->component_type_
__ LoadFromOffset(kLoadWord, out, out, component_offset);
- __ 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`.
__ CompareAndBranchIfZero(out, &done);
__ LoadFromOffset(kLoadUnsignedHalfword, out, out, primitive_offset);
@@ -4870,11 +5249,12 @@
__ b(&done);
break;
}
+
case TypeCheckKind::kArrayCheck: {
__ cmp(out, ShifterOperand(cls));
DCHECK(locations->OnlyCallsOnSlowPath());
- slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM(
- instruction, /* is_fatal */ false);
+ slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM(instruction,
+ /* is_fatal */ false);
codegen_->AddSlowPath(slow_path);
__ b(slow_path->GetEntryLabel(), NE);
__ LoadImmediate(out, 1);
@@ -4883,13 +5263,25 @@
}
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 & 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()) TypeCheckSlowPathARM(instruction,
+ /* is_fatal */ false);
+ codegen_->AddSlowPath(slow_path);
+ __ b(slow_path->GetEntryLabel());
if (zero.IsLinked()) {
__ b(&done);
}
@@ -4915,57 +5307,61 @@
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;
- break;
- case TypeCheckKind::kUnresolvedCheck:
- case TypeCheckKind::kInterfaceCheck:
- call_kind = LocationSummary::kCall;
+ 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::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 TypeCheckSlowPathARM uses this register too.
+ LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary(instruction, call_kind);
+ locations->SetInAt(0, Location::RequiresRegister());
+ locations->SetInAt(1, Location::RequiresRegister());
+ // Note that TypeCheckSlowPathARM uses this "temp" register too.
+ 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());
- } else {
- InvokeRuntimeCallingConvention calling_convention;
- locations->SetInAt(1, Location::RegisterLocation(calling_convention.GetRegisterAt(0)));
- locations->SetInAt(0, Location::RegisterLocation(calling_convention.GetRegisterAt(1)));
}
}
void InstructionCodeGeneratorARM::VisitCheckCast(HCheckCast* instruction) {
LocationSummary* locations = instruction->GetLocations();
- Register obj = locations->InAt(0).AsRegister<Register>();
+ Location obj_loc = locations->InAt(0);
+ Register obj = obj_loc.AsRegister<Register>();
Register cls = locations->InAt(1).AsRegister<Register>();
- Register temp = locations->WillCall()
- ? Register(kNoRegister)
- : locations->GetTemp(0).AsRegister<Register>();
-
+ Location temp_loc = locations->GetTemp(0);
+ Register temp = temp_loc.AsRegister<Register>();
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();
- SlowPathCode* slow_path = nullptr;
- if (!locations->WillCall()) {
- slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARM(
- 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();
+ SlowPathCode* type_check_slow_path =
+ new (GetGraph()->GetArena()) TypeCheckSlowPathARM(instruction,
+ is_type_check_slow_path_fatal);
+ codegen_->AddSlowPath(type_check_slow_path);
Label done;
// Avoid null check if we know obj is not null.
@@ -4973,76 +5369,159 @@
__ CompareAndBranchIfZero(obj, &done);
}
- if (locations->WillCall()) {
- __ LoadFromOffset(kLoadWord, obj, obj, class_offset);
- __ MaybeUnpoisonHeapReference(obj);
- } else {
- __ LoadFromOffset(kLoadWord, temp, obj, class_offset);
- __ MaybeUnpoisonHeapReference(temp);
- }
+ // /* HeapReference<Class> */ temp = obj->klass_
+ __ LoadFromOffset(kLoadWord, temp, 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, ShifterOperand(cls));
// Jump to slow path for throwing the exception or doing a
// more involved array check.
- __ b(slow_path->GetEntryLabel(), NE);
+ __ b(type_check_slow_path->GetEntryLabel(), NE);
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.
- Label loop;
+ 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 = temp2_loc.AsRegister<Register>();
+ __ Mov(temp2, temp);
+ }
+ // /* HeapReference<Class> */ temp = temp->super_class_
__ LoadFromOffset(kLoadWord, temp, temp, super_offset);
- __ MaybeUnpoisonHeapReference(temp);
- // Jump to the slow path to throw the exception.
- __ CompareAndBranchIfZero(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.
+ __ CompareAndBranchIfNonZero(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_
+ __ LoadFromOffset(kLoadWord, temp, 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, ShifterOperand(cls));
__ b(&loop, NE);
break;
}
+
case TypeCheckKind::kClassHierarchyCheck: {
// Walk over the class hierarchy to find a match.
Label loop;
__ Bind(&loop);
__ cmp(temp, ShifterOperand(cls));
__ b(&done, EQ);
+
+ 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 = temp2_loc.AsRegister<Register>();
+ __ Mov(temp2, temp);
+ }
+ // /* HeapReference<Class> */ temp = temp->super_class_
__ LoadFromOffset(kLoadWord, temp, temp, super_offset);
- __ 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.
__ CompareAndBranchIfNonZero(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_
+ __ LoadFromOffset(kLoadWord, temp, 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.
+ Label check_non_primitive_component_type;
__ cmp(temp, ShifterOperand(cls));
__ b(&done, EQ);
- // 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 = temp2_loc.AsRegister<Register>();
+ __ Mov(temp2, temp);
+ }
+ // /* HeapReference<Class> */ temp = temp->component_type_
__ LoadFromOffset(kLoadWord, temp, temp, component_offset);
- __ MaybeUnpoisonHeapReference(temp);
- __ CompareAndBranchIfZero(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.
+ __ CompareAndBranchIfNonZero(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_
+ __ LoadFromOffset(kLoadWord, temp, 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);
__ LoadFromOffset(kLoadUnsignedHalfword, temp, temp, primitive_offset);
- static_assert(Primitive::kPrimNot == 0, "Expected 0 for kPrimNot");
- __ CompareAndBranchIfNonZero(temp, slow_path->GetEntryLabel());
+ static_assert(Primitive::kPrimNot == 0, "Expected 0 for art::Primitive::kPrimNot");
+ __ CompareAndBranchIfZero(temp, &done);
+ // Same comment as above regarding `temp` and the slow path.
+ // /* HeapReference<Class> */ temp = obj->klass_
+ __ LoadFromOffset(kLoadWord, temp, 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 &
+ // 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 LocationsBuilderARM::VisitMonitorOperation(HMonitorOperation* instruction) {
@@ -5216,6 +5695,82 @@
}
}
+void CodeGeneratorARM::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.
+ SlowPathCode* slow_path = new (GetGraph()->GetArena())
+ ReadBarrierForHeapReferenceSlowPathARM(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 CodeGeneratorARM::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) {
+ __ UnpoisonHeapReference(out.AsRegister<Register>());
+ }
+}
+
+void CodeGeneratorARM::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.
+ SlowPathCode* slow_path =
+ new (GetGraph()->GetArena()) ReadBarrierForRootSlowPathARM(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());
+}
+
HInvokeStaticOrDirect::DispatchInfo CodeGeneratorARM::GetSupportedInvokeStaticOrDirectDispatch(
const HInvokeStaticOrDirect::DispatchInfo& desired_dispatch_info,
MethodReference target_method) {
@@ -5299,10 +5854,11 @@
method_reg = reg;
__ LoadFromOffset(kLoadWord, reg, SP, kCurrentMethodStackOffset);
}
- // temp = current_method->dex_cache_resolved_methods_;
- __ LoadFromOffset(
- kLoadWord, reg, method_reg, ArtMethod::DexCacheResolvedMethodsOffset(
- kArmPointerSize).Int32Value());
+ // /* ArtMethod*[] */ temp = temp.ptr_sized_fields_->dex_cache_resolved_methods_;
+ __ LoadFromOffset(kLoadWord,
+ reg,
+ method_reg,
+ ArtMethod::DexCacheResolvedMethodsOffset(kArmPointerSize).Int32Value());
// temp = temp[index_in_cache]
uint32_t index_in_cache = invoke->GetTargetMethod().dex_method_index;
__ LoadFromOffset(kLoadWord, reg, reg, CodeGenerator::GetCachePointerOffset(index_in_cache));
@@ -5346,10 +5902,17 @@
LocationSummary* locations = invoke->GetLocations();
Location receiver = locations->InAt(0);
uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
- // temp = object->GetClass();
DCHECK(receiver.IsRegister());
+ // /* HeapReference<Class> */ temp = receiver->klass_
__ LoadFromOffset(kLoadWord, temp, receiver.AsRegister<Register>(), 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).
__ MaybeUnpoisonHeapReference(temp);
// temp = temp->GetMethodAt(method_offset);
uint32_t entry_point = ArtMethod::EntryPointFromQuickCompiledCodeOffset(
diff --git a/compiler/optimizing/code_generator_arm.h b/compiler/optimizing/code_generator_arm.h
index 32bfe0f..89de4f8 100644
--- a/compiler/optimizing/code_generator_arm.h
+++ b/compiler/optimizing/code_generator_arm.h
@@ -373,6 +373,51 @@
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 MethodToLiteralMap = ArenaSafeMap<MethodReference, Literal*, MethodReferenceComparator>;
diff --git a/compiler/optimizing/intrinsics_arm.cc b/compiler/optimizing/intrinsics_arm.cc
index 0a5acc3..d2017da 100644
--- a/compiler/optimizing/intrinsics_arm.cc
+++ b/compiler/optimizing/intrinsics_arm.cc
@@ -44,7 +44,23 @@
bool IntrinsicLocationsBuilderARM::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
+ // IntrinsicSlowPathARM slow path. Currently this approach
+ // does not work when using read barriers, as the emitted
+ // calling sequence will make use of another slow path
+ // (ReadBarrierForRootSlowPathARM for HInvokeStaticOrDirect,
+ // ReadBarrierSlowPathARM 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 __ assembler->
@@ -662,20 +678,23 @@
(type == Primitive::kPrimLong) ||
(type == Primitive::kPrimNot));
ArmAssembler* assembler = codegen->GetAssembler();
- Register base = locations->InAt(1).AsRegister<Register>(); // Object pointer.
- Register offset = locations->InAt(2).AsRegisterPairLow<Register>(); // Long offset, lo part only.
+ Location base_loc = locations->InAt(1);
+ Register base = base_loc.AsRegister<Register>(); // Object pointer.
+ Location offset_loc = locations->InAt(2);
+ Register offset = offset_loc.AsRegisterPairLow<Register>(); // Long offset, lo part only.
+ Location trg_loc = locations->Out();
if (type == Primitive::kPrimLong) {
- Register trg_lo = locations->Out().AsRegisterPairLow<Register>();
+ Register trg_lo = trg_loc.AsRegisterPairLow<Register>();
__ add(IP, base, ShifterOperand(offset));
if (is_volatile && !codegen->GetInstructionSetFeatures().HasAtomicLdrdAndStrd()) {
- Register trg_hi = locations->Out().AsRegisterPairHigh<Register>();
+ Register trg_hi = trg_loc.AsRegisterPairHigh<Register>();
__ ldrexd(trg_lo, trg_hi, IP);
} else {
__ ldrd(trg_lo, Address(IP));
}
} else {
- Register trg = locations->Out().AsRegister<Register>();
+ Register trg = trg_loc.AsRegister<Register>();
__ ldr(trg, Address(base, offset));
}
@@ -684,14 +703,18 @@
}
if (type == Primitive::kPrimNot) {
- Register trg = locations->Out().AsRegister<Register>();
- __ 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());
@@ -936,6 +959,7 @@
__ Bind(&loop_head);
__ ldrex(tmp_lo, tmp_ptr);
+ // TODO: Do we need a read barrier here when `type == Primitive::kPrimNot`?
__ subs(tmp_lo, tmp_lo, ShifterOperand(expected_lo));
@@ -964,7 +988,11 @@
// 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;
}
@@ -1400,6 +1428,10 @@
}
}
+// TODO: Implement read barriers in the SystemArrayCopy intrinsic.
+// Note that this code path is not used (yet) because we do not
+// intrinsify methods that can go into the IntrinsicSlowPathARM
+// slow path.
void IntrinsicCodeGeneratorARM::VisitSystemArrayCopy(HInvoke* invoke) {
ArmAssembler* assembler = GetAssembler();
LocationSummary* locations = invoke->GetLocations();
diff --git a/compiler/optimizing/optimizing_compiler.cc b/compiler/optimizing/optimizing_compiler.cc
index 27ee472..2204921 100644
--- a/compiler/optimizing/optimizing_compiler.cc
+++ b/compiler/optimizing/optimizing_compiler.cc
@@ -383,10 +383,11 @@
|| instruction_set == kX86_64;
}
-// Read barrier are supported only on x86 and x86-64 at the moment.
+// Read barrier are supported only on ARM, 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 == kX86
+ return instruction_set == kThumb2
+ || instruction_set == kX86
|| instruction_set == kX86_64;
}
@@ -668,8 +669,8 @@
CompilerDriver* compiler_driver = GetCompilerDriver();
InstructionSet instruction_set = compiler_driver->GetInstructionSet();
- // Always use the thumb2 assembler: some runtime functionality (like implicit stack
- // overflow checks) assume thumb2.
+ // Always use the Thumb-2 assembler: some runtime functionality
+ // (like implicit stack overflow checks) assume Thumb-2.
if (instruction_set == kArm) {
instruction_set = kThumb2;
}
diff --git a/test/run-test b/test/run-test
index 10ec310..d0da34e 100755
--- a/test/run-test
+++ b/test/run-test
@@ -669,9 +669,9 @@
# -------------------------------
# Return whether the Optimizing compiler has read barrier support for ARCH.
function arch_supports_read_barrier() {
- # Optimizing has read barrier support for x86 and x86-64 at the
+ # Optimizing has read barrier support for ARM, x86 and x86-64 at the
# moment.
- [ "x$1" = xx86 ] || [ "x$1" = xx86_64 ]
+ [ "x$1" = xarm ] || [ "x$1" = xx86 ] || [ "x$1" = xx86_64 ]
}
# Tests named '<number>-checker-*' will also have their CFGs verified with