Rename art::ReadBarrier::WhiteState as art::ReadBarrier::NonGrayState.

The read barrier state recorded in object's lockword used to be a
three-state value (white/gray/black), which was turned into a
two-state value (white/gray), where the "black" state was conceptually
merged into the "white" state. This change renames the "white" state
as "non-gray" and adjusts corresponding comments.

Test: art/test.py
Change-Id: I2a17ed15651bdbbe99270c1b81b4d78a1c2c132b
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 15e3d27..462225a 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -6162,7 +6162,7 @@
   // Load the lock word containing the rb_state.
   __ Ldr(ip0.W(), lock_word);
   // Given the numeric representation, it's enough to check the low bit of the rb_state.
-  static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+  static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
   static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
   __ Tbnz(ip0.W(), LockWord::kReadBarrierStateShift, slow_path);
   static_assert(
diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index f624216..d811e07 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -899,7 +899,7 @@
     // 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::WhiteState() == 0, "Expecting white to have value 0");
+    static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
     static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
     __ Lsrs(temp1_, temp1_, LockWord::kReadBarrierStateShift + 1);
     __ B(cc, GetExitLabel());  // Carry flag is the last bit shifted out by LSRS.
@@ -9661,7 +9661,7 @@
   // Load the lock word containing the rb_state.
   __ Ldr(ip, lock_word);
   // Given the numeric representation, it's enough to check the low bit of the rb_state.
-  static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+  static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
   static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
   __ Tst(ip, Operand(LockWord::kReadBarrierStateMaskShifted));
   __ B(ne, slow_path, /* is_far_target */ false);
diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index 476e8ab..aed334b 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -7454,7 +7454,7 @@
   // Given the numeric representation, it's enough to check the low bit of the
   // rb_state. We do that by shifting the bit into the sign bit (31) and
   // performing a branch on less than zero.
-  static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+  static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
   static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
   static_assert(LockWord::kReadBarrierStateSize == 1, "Expecting 1-bit read barrier state size");
   __ Sll(temp_reg, temp_reg, 31 - LockWord::kReadBarrierStateShift);
diff --git a/compiler/optimizing/code_generator_mips64.cc b/compiler/optimizing/code_generator_mips64.cc
index c05f627..72318e9 100644
--- a/compiler/optimizing/code_generator_mips64.cc
+++ b/compiler/optimizing/code_generator_mips64.cc
@@ -5570,7 +5570,7 @@
   // Given the numeric representation, it's enough to check the low bit of the
   // rb_state. We do that by shifting the bit into the sign bit (31) and
   // performing a branch on less than zero.
-  static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+  static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
   static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
   static_assert(LockWord::kReadBarrierStateSize == 1, "Expecting 1-bit read barrier state size");
   __ Sll(temp_reg, temp_reg, 31 - LockWord::kReadBarrierStateShift);
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 63bd841..df00ec7 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -7757,7 +7757,7 @@
   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::WhiteState() == 0, "Expecting white to have value 0");
+  static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray 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;
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 0bd7319..ae2a000 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -7050,7 +7050,7 @@
   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::WhiteState() == 0, "Expecting white to have value 0");
+  static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray 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;
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index 74d4a8f..a657b58 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -2739,7 +2739,7 @@
         codegen_->AddSlowPath(read_barrier_slow_path);
 
         // Given the numeric representation, it's enough to check the low bit of the rb_state.
-        static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+        static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
         static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
         __ Tbnz(tmp, LockWord::kReadBarrierStateShift, read_barrier_slow_path->GetEntryLabel());
 
diff --git a/compiler/optimizing/intrinsics_arm_vixl.cc b/compiler/optimizing/intrinsics_arm_vixl.cc
index b920750..53b0aa2 100644
--- a/compiler/optimizing/intrinsics_arm_vixl.cc
+++ b/compiler/optimizing/intrinsics_arm_vixl.cc
@@ -2205,7 +2205,7 @@
       // 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::WhiteState() == 0, "Expecting white to have value 0");
+      static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray to have value 0");
       static_assert(ReadBarrier::GrayState() == 1, "Expecting gray to have value 1");
       __ Lsrs(temp2, temp2, LockWord::kReadBarrierStateShift + 1);
       // Carry flag is the last bit shifted out by LSRS.
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index 98cea35..5c7be54 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -2781,7 +2781,7 @@
     __ j(kEqual, &done);
 
     // Given the numeric representation, it's enough to check the low bit of the rb_state.
-    static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+    static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray 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;
diff --git a/compiler/optimizing/intrinsics_x86_64.cc b/compiler/optimizing/intrinsics_x86_64.cc
index ac6eab0..b5afe93 100644
--- a/compiler/optimizing/intrinsics_x86_64.cc
+++ b/compiler/optimizing/intrinsics_x86_64.cc
@@ -1143,7 +1143,7 @@
     __ j(kEqual, &done);
 
     // Given the numeric representation, it's enough to check the low bit of the rb_state.
-    static_assert(ReadBarrier::WhiteState() == 0, "Expecting white to have value 0");
+    static_assert(ReadBarrier::NonGrayState() == 0, "Expecting non-gray 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;