Improve ArraySet codegen.
Simplify the reference case to emit fewer instructions and
take at most one branch in the main path.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: aosp_taimen-userdebug boots.
Test: testrunner.py --target --optimizing
Bug: 32489401
Change-Id: I9d76b7795ec01e6245ed3184cd8d384389e5070d
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 3086882..d206669 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -2497,12 +2497,10 @@
void LocationsBuilderARM64::VisitArraySet(HArraySet* instruction) {
DataType::Type value_type = instruction->GetComponentType();
- bool may_need_runtime_call_for_type_check = instruction->NeedsTypeCheck();
+ bool needs_type_check = instruction->NeedsTypeCheck();
LocationSummary* locations = new (GetGraph()->GetAllocator()) LocationSummary(
instruction,
- may_need_runtime_call_for_type_check ?
- LocationSummary::kCallOnSlowPath :
- LocationSummary::kNoCall);
+ needs_type_check ? LocationSummary::kCallOnSlowPath : LocationSummary::kNoCall);
locations->SetInAt(0, Location::RequiresRegister());
locations->SetInAt(1, Location::RegisterOrConstant(instruction->InputAt(1)));
if (IsConstantZeroBitPattern(instruction->InputAt(2))) {
@@ -2517,7 +2515,7 @@
void InstructionCodeGeneratorARM64::VisitArraySet(HArraySet* instruction) {
DataType::Type value_type = instruction->GetComponentType();
LocationSummary* locations = instruction->GetLocations();
- bool may_need_runtime_call_for_type_check = instruction->NeedsTypeCheck();
+ bool needs_type_check = instruction->NeedsTypeCheck();
bool needs_write_barrier =
CodeGenerator::StoreNeedsWriteBarrier(value_type, instruction->GetValue());
@@ -2530,7 +2528,7 @@
MacroAssembler* masm = GetVIXLAssembler();
if (!needs_write_barrier) {
- DCHECK(!may_need_runtime_call_for_type_check);
+ DCHECK(!needs_type_check);
if (index.IsConstant()) {
offset += Int64FromLocation(index) << DataType::SizeShift(value_type);
destination = HeapOperand(array, offset);
@@ -2562,128 +2560,105 @@
}
} else {
DCHECK(!instruction->GetArray()->IsIntermediateAddress());
- vixl::aarch64::Label done;
- SlowPathCodeARM64* slow_path = nullptr;
- {
- // We use a block to end the scratch scope before the write barrier, thus
- // freeing the temporary registers so they can be used in `MarkGCCard`.
+
+ bool can_value_be_null = instruction->GetValueCanBeNull();
+ vixl::aarch64::Label do_store;
+ if (can_value_be_null) {
+ __ Cbz(Register(value), &do_store);
+ }
+
+ if (needs_type_check) {
+ SlowPathCodeARM64* slow_path =
+ new (codegen_->GetScopedAllocator()) ArraySetSlowPathARM64(instruction);
+ codegen_->AddSlowPath(slow_path);
+
+ const uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
+ const uint32_t super_offset = mirror::Class::SuperClassOffset().Int32Value();
+ const uint32_t component_offset = mirror::Class::ComponentTypeOffset().Int32Value();
+
UseScratchRegisterScope temps(masm);
Register temp = temps.AcquireSameSizeAs(array);
- if (index.IsConstant()) {
- offset += Int64FromLocation(index) << DataType::SizeShift(value_type);
- destination = HeapOperand(array, offset);
- } else {
- destination = HeapOperand(temp,
- XRegisterFrom(index),
- LSL,
- DataType::SizeShift(value_type));
+ Register temp2 = temps.AcquireSameSizeAs(array);
+
+ // Note that when Baker read barriers are enabled, the type
+ // checks are performed without read barriers. This is fine,
+ // even in the case where a class object is in the from-space
+ // after the flip, as a comparison involving such a type would
+ // not produce a false positive; it may of course produce a
+ // false negative, in which case we would take the ArraySet
+ // slow path.
+
+ // /* HeapReference<Class> */ temp = array->klass_
+ {
+ // Ensure that between load and MaybeRecordImplicitNullCheck there are no pools emitted.
+ EmissionCheckScope guard(GetVIXLAssembler(), kMaxMacroInstructionSizeInBytes);
+ __ Ldr(temp, HeapOperand(array, class_offset));
+ codegen_->MaybeRecordImplicitNullCheck(instruction);
}
+ GetAssembler()->MaybeUnpoisonHeapReference(temp);
- uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
- uint32_t super_offset = mirror::Class::SuperClassOffset().Int32Value();
- uint32_t component_offset = mirror::Class::ComponentTypeOffset().Int32Value();
+ // /* 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 (may_need_runtime_call_for_type_check) {
- slow_path = new (codegen_->GetScopedAllocator()) ArraySetSlowPathARM64(instruction);
- codegen_->AddSlowPath(slow_path);
- if (instruction->GetValueCanBeNull()) {
- vixl::aarch64::Label non_zero;
- __ Cbnz(Register(value), &non_zero);
- if (!index.IsConstant()) {
- __ Add(temp, array, offset);
- }
- {
- // Ensure that between store and MaybeRecordImplicitNullCheck there are no pools
- // emitted.
- EmissionCheckScope guard(GetVIXLAssembler(), kMaxMacroInstructionSizeInBytes);
- __ Str(wzr, destination);
- codegen_->MaybeRecordImplicitNullCheck(instruction);
- }
- __ B(&done);
- __ Bind(&non_zero);
- }
-
- // Note that when Baker read barriers are enabled, the type
- // checks are performed without read barriers. This is fine,
- // even in the case where a class object is in the from-space
- // after the flip, as a comparison involving such a type would
- // not produce a false positive; it may of course produce a
- // false negative, in which case we would take the ArraySet
- // slow path.
-
- Register temp2 = temps.AcquireSameSizeAs(array);
- // /* HeapReference<Class> */ temp = array->klass_
- {
- // Ensure that between load and MaybeRecordImplicitNullCheck there are no pools emitted.
- EmissionCheckScope guard(GetVIXLAssembler(), kMaxMacroInstructionSizeInBytes);
- __ Ldr(temp, HeapOperand(array, class_offset));
- codegen_->MaybeRecordImplicitNullCheck(instruction);
- }
+ if (instruction->StaticTypeOfArrayIsObjectArray()) {
+ __ B(eq, slow_path->GetExitLabel());
+ // If heap poisoning is enabled, the `temp` reference has
+ // not been unpoisoned yet; unpoison it now.
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);
- temps.Release(temp2);
-
- if (instruction->StaticTypeOfArrayIsObjectArray()) {
- vixl::aarch64::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());
- }
- }
-
- if (kPoisonHeapReferences) {
- Register temp2 = temps.AcquireSameSizeAs(array);
- DCHECK(value.IsW());
- __ Mov(temp2, value.W());
- GetAssembler()->PoisonHeapReference(temp2);
- source = temp2;
- }
-
- if (!index.IsConstant()) {
- __ Add(temp, array, offset);
+ // /* 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());
} else {
- // We no longer need the `temp` here so release it as the store below may
- // need a scratch register (if the constant index makes the offset too large)
- // and the poisoned `source` could be using the other scratch register.
- temps.Release(temp);
+ __ B(ne, slow_path->GetEntryLabel());
}
- {
- // Ensure that between store and MaybeRecordImplicitNullCheck there are no pools emitted.
- EmissionCheckScope guard(GetVIXLAssembler(), kMaxMacroInstructionSizeInBytes);
- __ Str(source, destination);
-
- if (!may_need_runtime_call_for_type_check) {
- codegen_->MaybeRecordImplicitNullCheck(instruction);
- }
- }
- }
-
- codegen_->MarkGCCard(array, value.W(), instruction->GetValueCanBeNull());
-
- if (done.IsLinked()) {
- __ Bind(&done);
- }
-
- if (slow_path != nullptr) {
__ Bind(slow_path->GetExitLabel());
}
+
+ codegen_->MarkGCCard(array, value.W(), /* value_can_be_null= */ false);
+
+ UseScratchRegisterScope temps(masm);
+ if (kPoisonHeapReferences) {
+ Register temp_source = temps.AcquireSameSizeAs(array);
+ DCHECK(value.IsW());
+ __ Mov(temp_source, value.W());
+ GetAssembler()->PoisonHeapReference(temp_source);
+ source = temp_source;
+ }
+
+ if (can_value_be_null) {
+ DCHECK(do_store.IsLinked());
+ __ Bind(&do_store);
+ }
+
+ if (index.IsConstant()) {
+ offset += Int64FromLocation(index) << DataType::SizeShift(value_type);
+ destination = HeapOperand(array, offset);
+ } else {
+ Register temp_base = temps.AcquireSameSizeAs(array);
+ __ Add(temp_base, array, offset);
+ destination = HeapOperand(temp_base,
+ XRegisterFrom(index),
+ LSL,
+ DataType::SizeShift(value_type));
+ }
+
+ {
+ // Ensure that between store and MaybeRecordImplicitNullCheck there are no pools emitted.
+ EmissionCheckScope guard(GetVIXLAssembler(), kMaxMacroInstructionSizeInBytes);
+ __ Str(source, destination);
+
+ if (can_value_be_null || !needs_type_check) {
+ codegen_->MaybeRecordImplicitNullCheck(instruction);
+ }
+ }
}
}