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

1 files changed, 4 insertions, 5 deletions

diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index be65f89ef1..57823c9684 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -6843,7 +6843,7 @@ void CodeGeneratorARM::GenerateReferenceLoadWithBakerReadBarrier(HInstruction* i
   //   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.
   //   }
@@ -6919,14 +6919,13 @@ void CodeGeneratorARM::GenerateReferenceLoadWithBakerReadBarrier(HInstruction* i
   }
   AddSlowPath(slow_path);
 
-  // if (rb_state == ReadBarrier::gray_ptr_)
+  // if (rb_state == ReadBarrier::GrayState())
   //   ref = ReadBarrier::Mark(ref);
   // Given the numeric representation, it's enough to check the low bit of the
   // rb_state. We do that by shifting the bit out of the lock word with LSRS
   // which can be a 16-bit instruction unlike the TST immediate.
-  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");
   __ Lsrs(temp_reg, temp_reg, LockWord::kReadBarrierStateShift + 1);
   __ b(slow_path->GetEntryLabel(), CS);  // Carry flag is the last bit shifted out by LSRS.
   __ Bind(slow_path->GetExitLabel());