Some read barrier clean-up in Optimizing.
These changes make the read barrier compiler instrumentation
code more uniform among the ARM, ARM64, x86 and x86-64 back
ends.
Bug: 12687968
Change-Id: I6b1c0cf2bc22ed6cd6b14754136bef4a2a036ea5
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 31f3660..2ce2d91 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -4663,13 +4663,13 @@
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 || object_array_set_with_read_barrier) ?
+ (may_need_runtime_call_for_type_check || object_array_set_with_read_barrier) ?
LocationSummary::kCallOnSlowPath :
LocationSummary::kNoCall);
@@ -4698,7 +4698,7 @@
Location index = locations->InAt(1);
Location value = locations->InAt(2);
Primitive::Type value_type = instruction->GetComponentType();
- bool may_need_runtime_call = instruction->NeedsTypeCheck();
+ bool may_need_runtime_call_for_type_check = instruction->NeedsTypeCheck();
bool needs_write_barrier =
CodeGenerator::StoreNeedsWriteBarrier(value_type, instruction->GetValue());
uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
@@ -4750,7 +4750,7 @@
__ movl(address, Immediate(0));
codegen_->MaybeRecordImplicitNullCheck(instruction);
DCHECK(!needs_write_barrier);
- DCHECK(!may_need_runtime_call);
+ DCHECK(!may_need_runtime_call_for_type_check);
break;
}
@@ -4759,7 +4759,7 @@
NearLabel done, not_null, do_put;
SlowPathCode* slow_path = nullptr;
CpuRegister temp = locations->GetTemp(0).AsRegister<CpuRegister>();
- if (may_need_runtime_call) {
+ if (may_need_runtime_call_for_type_check) {
slow_path = new (GetGraph()->GetArena()) ArraySetSlowPathX86_64(instruction);
codegen_->AddSlowPath(slow_path);
if (instruction->GetValueCanBeNull()) {
@@ -4837,7 +4837,7 @@
} else {
__ movl(address, register_value);
}
- if (!may_need_runtime_call) {
+ if (!may_need_runtime_call_for_type_check) {
codegen_->MaybeRecordImplicitNullCheck(instruction);
}
@@ -5626,7 +5626,7 @@
case TypeCheckKind::kUnresolvedCheck:
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
+ // into the slow path for the unresolved and interface check
// cases.
//
// We cannot directly call the InstanceofNonTrivial runtime
@@ -5857,8 +5857,8 @@
case TypeCheckKind::kUnresolvedCheck:
case TypeCheckKind::kInterfaceCheck:
- // We always go into the type check slow path for the unresolved &
- // interface check cases.
+ // 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
@@ -6120,6 +6120,8 @@
// Plain GC root load with no read barrier.
// /* GcRoot<mirror::Object> */ root = *(obj + offset)
__ movl(root_reg, Address(obj, offset));
+ // Note that GC roots are not affected by heap poisoning, thus we
+ // do not have to unpoison `root_reg` here.
}
}
@@ -6182,7 +6184,9 @@
// Note: the original implementation in ReadBarrier::Barrier is
// slightly more complex as:
// - it implements the load-load fence using a data dependency on
- // the high-bits of rb_state, which are expected to be all zeroes;
+ // the high-bits of rb_state, which are expected to be all zeroes
+ // (we use CodeGeneratorX86_64::GenerateMemoryBarrier instead
+ // here, which is a no-op thanks to the x86-64 memory model);
// - it performs additional checks that we do not do here for
// performance reasons.