Improve documentation and assertions of read barrier instrumentation.
For ARM, x86, x86-64 back ends. The case of the ARM64 back
end is already handled in
https://android-review.googlesource.com/#/c/197870/.
Bug: 12687968
Change-Id: I6df1128cc100cbdb89020876e1a54de719508be3
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 2ce2d91..fd18834 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -5490,7 +5490,7 @@
Location cls = locations->InAt(1);
Location out_loc = locations->Out();
CpuRegister out = out_loc.AsRegister<CpuRegister>();
- Location temp_loc = TypeCheckNeedsATemporary(type_check_kind) ?
+ Location maybe_temp_loc = TypeCheckNeedsATemporary(type_check_kind) ?
locations->GetTemp(0) :
Location::NoLocation();
uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
@@ -5508,7 +5508,7 @@
}
// /* HeapReference<Class> */ out = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, out_loc, obj_loc, class_offset, temp_loc);
+ GenerateReferenceLoadTwoRegisters(instruction, out_loc, obj_loc, class_offset, maybe_temp_loc);
switch (type_check_kind) {
case TypeCheckKind::kExactCheck: {
@@ -5537,7 +5537,7 @@
NearLabel loop, success;
__ Bind(&loop);
// /* HeapReference<Class> */ out = out->super_class_
- GenerateReferenceLoadOneRegister(instruction, out_loc, super_offset, temp_loc);
+ GenerateReferenceLoadOneRegister(instruction, out_loc, super_offset, maybe_temp_loc);
__ testl(out, out);
// If `out` is null, we use it for the result, and jump to `done`.
__ j(kEqual, &done);
@@ -5567,7 +5567,7 @@
}
__ j(kEqual, &success);
// /* HeapReference<Class> */ out = out->super_class_
- GenerateReferenceLoadOneRegister(instruction, out_loc, super_offset, temp_loc);
+ GenerateReferenceLoadOneRegister(instruction, out_loc, super_offset, maybe_temp_loc);
__ testl(out, out);
__ j(kNotEqual, &loop);
// If `out` is null, we use it for the result, and jump to `done`.
@@ -5592,7 +5592,7 @@
__ j(kEqual, &exact_check);
// Otherwise, we need to check that the object's class is a non-primitive array.
// /* HeapReference<Class> */ out = out->component_type_
- GenerateReferenceLoadOneRegister(instruction, out_loc, component_offset, temp_loc);
+ GenerateReferenceLoadOneRegister(instruction, out_loc, component_offset, maybe_temp_loc);
__ testl(out, out);
// If `out` is null, we use it for the result, and jump to `done`.
__ j(kEqual, &done);
@@ -5708,7 +5708,7 @@
Location cls = locations->InAt(1);
Location temp_loc = locations->GetTemp(0);
CpuRegister temp = temp_loc.AsRegister<CpuRegister>();
- Location temp2_loc = TypeCheckNeedsATemporary(type_check_kind) ?
+ Location maybe_temp2_loc = TypeCheckNeedsATemporary(type_check_kind) ?
locations->GetTemp(1) :
Location::NoLocation();
uint32_t class_offset = mirror::Object::ClassOffset().Int32Value();
@@ -5735,7 +5735,7 @@
}
// /* HeapReference<Class> */ temp = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, temp2_loc);
+ GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
switch (type_check_kind) {
case TypeCheckKind::kExactCheck:
@@ -5758,7 +5758,7 @@
NearLabel loop, compare_classes;
__ Bind(&loop);
// /* HeapReference<Class> */ temp = temp->super_class_
- GenerateReferenceLoadOneRegister(instruction, temp_loc, super_offset, temp2_loc);
+ GenerateReferenceLoadOneRegister(instruction, temp_loc, super_offset, maybe_temp2_loc);
// If the class reference currently in `temp` is not null, jump
// to the `compare_classes` label to compare it with the checked
@@ -5771,7 +5771,8 @@
// going into the slow path, as it has been overwritten in the
// meantime.
// /* HeapReference<Class> */ temp = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, temp2_loc);
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
__ jmp(type_check_slow_path->GetEntryLabel());
__ Bind(&compare_classes);
@@ -5798,7 +5799,7 @@
__ j(kEqual, &done);
// /* HeapReference<Class> */ temp = temp->super_class_
- GenerateReferenceLoadOneRegister(instruction, temp_loc, super_offset, temp2_loc);
+ GenerateReferenceLoadOneRegister(instruction, temp_loc, super_offset, maybe_temp2_loc);
// If the class reference currently in `temp` is not null, jump
// back at the beginning of the loop.
@@ -5810,7 +5811,8 @@
// going into the slow path, as it has been overwritten in the
// meantime.
// /* HeapReference<Class> */ temp = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, temp2_loc);
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
__ jmp(type_check_slow_path->GetEntryLabel());
break;
}
@@ -5828,7 +5830,7 @@
// Otherwise, we need to check that the object's class is a non-primitive array.
// /* HeapReference<Class> */ temp = temp->component_type_
- GenerateReferenceLoadOneRegister(instruction, temp_loc, component_offset, temp2_loc);
+ GenerateReferenceLoadOneRegister(instruction, temp_loc, component_offset, maybe_temp2_loc);
// If the component type is not null (i.e. the object is indeed
// an array), jump to label `check_non_primitive_component_type`
@@ -5842,7 +5844,8 @@
// going into the slow path, as it has been overwritten in the
// meantime.
// /* HeapReference<Class> */ temp = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, temp2_loc);
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
__ jmp(type_check_slow_path->GetEntryLabel());
__ Bind(&check_non_primitive_component_type);
@@ -5850,7 +5853,8 @@
__ j(kEqual, &done);
// Same comment as above regarding `temp` and the slow path.
// /* HeapReference<Class> */ temp = obj->klass_
- GenerateReferenceLoadTwoRegisters(instruction, temp_loc, obj_loc, class_offset, temp2_loc);
+ GenerateReferenceLoadTwoRegisters(
+ instruction, temp_loc, obj_loc, class_offset, maybe_temp2_loc);
__ jmp(type_check_slow_path->GetEntryLabel());
break;
}
@@ -6020,23 +6024,24 @@
void InstructionCodeGeneratorX86_64::GenerateReferenceLoadOneRegister(HInstruction* instruction,
Location out,
uint32_t offset,
- Location temp) {
+ Location maybe_temp) {
CpuRegister out_reg = out.AsRegister<CpuRegister>();
if (kEmitCompilerReadBarrier) {
+ DCHECK(maybe_temp.IsRegister()) << maybe_temp;
if (kUseBakerReadBarrier) {
// Load with fast path based Baker's read barrier.
// /* HeapReference<Object> */ out = *(out + offset)
codegen_->GenerateFieldLoadWithBakerReadBarrier(
- instruction, out, out_reg, offset, temp, /* needs_null_check */ false);
+ instruction, out, out_reg, offset, maybe_temp, /* needs_null_check */ false);
} else {
// Load with slow path based read barrier.
- // Save the value of `out` into `temp` before overwriting it
+ // Save the value of `out` into `maybe_temp` before overwriting it
// in the following move operation, as we will need it for the
// read barrier below.
- __ movl(temp.AsRegister<CpuRegister>(), out_reg);
+ __ movl(maybe_temp.AsRegister<CpuRegister>(), out_reg);
// /* HeapReference<Object> */ out = *(out + offset)
__ movl(out_reg, Address(out_reg, offset));
- codegen_->GenerateReadBarrierSlow(instruction, out, out, temp, offset);
+ codegen_->GenerateReadBarrierSlow(instruction, out, out, maybe_temp, offset);
}
} else {
// Plain load with no read barrier.
@@ -6050,15 +6055,16 @@
Location out,
Location obj,
uint32_t offset,
- Location temp) {
+ Location maybe_temp) {
CpuRegister out_reg = out.AsRegister<CpuRegister>();
CpuRegister obj_reg = obj.AsRegister<CpuRegister>();
if (kEmitCompilerReadBarrier) {
if (kUseBakerReadBarrier) {
+ DCHECK(maybe_temp.IsRegister()) << maybe_temp;
// Load with fast path based Baker's read barrier.
// /* HeapReference<Object> */ out = *(obj + offset)
codegen_->GenerateFieldLoadWithBakerReadBarrier(
- instruction, out, obj_reg, offset, temp, /* needs_null_check */ false);
+ instruction, out, obj_reg, offset, maybe_temp, /* needs_null_check */ false);
} else {
// Load with slow path based read barrier.
// /* HeapReference<Object> */ out = *(obj + offset)