Clean up the runtime read barrier and fix fake address dependency.
- Rename GetReadBarrierPointer to GetReadBarrierState.
- Change its return type to uint32_t.
- Fix the runtime fake address dependency for arm/arm64 using inline
asm.
- Drop ReadBarrier::black_ptr_ and some brooks code.
Bug: 12687968
Test: test-art with CC, Ritz EAAC, libartd boot on N9.
Change-Id: I595970db825db5be2e98ee1fcbd7696d5501af55
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index fcabeea..49f33d2 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -6535,7 +6535,7 @@
// uint32_t rb_state = Lockword(obj->monitor_).ReadBarrierState();
// lfence; // Load fence or artificial data dependency to prevent load-load reordering
// HeapReference<Object> ref = *src; // Original reference load.
- // bool is_gray = (rb_state == ReadBarrier::gray_ptr_);
+ // bool is_gray = (rb_state == ReadBarrier::GrayState());
// if (is_gray) {
// ref = ReadBarrier::Mark(ref); // Performed by runtime entrypoint slow path.
// }
@@ -6553,14 +6553,13 @@
uint32_t monitor_offset = mirror::Object::MonitorOffset().Int32Value();
// Given the numeric representation, it's enough to check the low bit of the rb_state.
- static_assert(ReadBarrier::white_ptr_ == 0, "Expecting white to have value 0");
- static_assert(ReadBarrier::gray_ptr_ == 1, "Expecting gray to have value 1");
- static_assert(ReadBarrier::black_ptr_ == 2, "Expecting black to have value 2");
+ static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+ static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
constexpr uint32_t gray_byte_position = LockWord::kReadBarrierStateShift / kBitsPerByte;
constexpr uint32_t gray_bit_position = LockWord::kReadBarrierStateShift % kBitsPerByte;
constexpr int32_t test_value = static_cast<int8_t>(1 << gray_bit_position);
- // if (rb_state == ReadBarrier::gray_ptr_)
+ // if (rb_state == ReadBarrier::GrayState())
// ref = ReadBarrier::Mark(ref);
// At this point, just do the "if" and make sure that flags are preserved until the branch.
__ testb(Address(obj, monitor_offset + gray_byte_position), Immediate(test_value));